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SDLRC - Scientific Articles all years by Author - J


The Sheahan Diamond Literature Reference Compilation
The Sheahan Diamond Literature Reference Compilation is compiled by Patricia Sheahan who publishes on a monthly basis a list of new scientific articles related to diamonds as well as media coverage and corporate announcementscalled the Sheahan Diamond Literature Service that is distributed as a free pdf to a list of followers. Pat has kindly agreed to allow her work to be made available as an online digital resource at Kaiser Research Online so that a broader community interested in diamonds and related geology can benefit. The references are for personal use information purposes only; when available a link is provided to an online location where the full article can be accessed or purchased directly. Reproduction of this compilation in part or in whole without permission from the Sheahan Diamond Literature Service is strictly prohibited. Return to Diamond Resource Center
Sheahan Diamond Literature Reference Compilation - Scientific Articles by Author for all years
A-An Ao+ B-Bd Be-Bk Bl-Bq Br+ C-Cg Ch-Ck Cl+ D-Dd De-Dn Do+ E F-Fn Fo+ G-Gh Gi-Gq Gr+ H-Hd He-Hn Ho+ I J K-Kg Kh-Kn Ko-Kq Kr+ L-Lh
Li+ M-Maq Mar-Mc Md-Mn Mo+ N O P-Pd Pe-Pn Po+ Q R-Rh Ri-Rn Ro+ S-Sd Se-Sh Si-Sm Sn-Ss St+ T-Th Ti+ U V W-Wg Wh+ X Y Z
Sheahan Diamond Literature Reference Compilation - Media/Corporate References by Name for all years
A B C D-Diam Diamonds Diamr+ E F G H I J K L M N O P Q R S T U V W X Y Z
Tips for Users
Posted/Published Reference CodesThe SDLRC provides 3 types of references identified in the reference code. DS for scientific article, DM for a media article, and DC for a corporate announcement. Consider DS0512-0001. The DS stands for "diamond scientific". 05 stands for 2005, the year the reference was posted. 12 represents the month the reference was posted. For all years prior to 2015 the default month is 12. -0001 is the reference's identifier and it does not mean anything. The number below the refence code, ie 2015, is the year the article was published. Note that the posted year may sometimes be later than the published year.
Sort OrderReferences are sorted by the "author" name and when the reference was posted to the compilation.
Most RecentIf the reference code is highlighted yellow, the reference was made available through the most recent monthly compilation of new literature. Use this to check out new references. When new references are posted, we make it our priority to track down an online link and obtain an abstract. With regard to older references, tracking down an abstract and an online link is a work in progress.
Link to external location of article: If the title has a link, it means we have found a location online where you can either retrieve the full article free, or purchase access to it. The Sheahan Diamond Literature Service is not a technical article procurement service; if you want a restricted article, you must deal directly with the vendor who controls the copyright to the article.
Searching this page for a specific term or authorIn your Firefox browser click Edit in the menu bar and then Find. In the Find box that shows up at the bottom of the web page enter your search term. Firefox will highlight all occurrences. This is particularly helpful when the author you are seeking was not the lead author by whom the compilation is sorted.
Sending or sharing a referenceThe left column (Posted/Published) has an embedded hyperlink for each reference. In Firefox, if you right click on it, you can obtain the link url for that reference's location within the page, which you can copy and paste into an email or any other document. You can also use the "share this link" option to tweet, facebook etc the link.
Author Index
A-An Ao+ B-Bd Be-Bk Bl-Bq Br+ C-Cg Ch-Ck Cl+ D-Dd De-Dn Do+ E F-Fn Fo+ G-Gh Gi-Gq Gr+ H-Hd He-Hn Ho+ I J K-Kg Kh-Kn Ko-Kq Kr+ L-Lh
Li+ M-Maq Mar-Mc Md-Mn Mo+ N O P-Pd Pe-Pn Po+ Q R-Rh Ri-Rn Ro+ S-Sd Se-Sh Si-Sm Sn-Ss St+ T-Th Ti+ U V W-Wg Wh+ X Y Z
Sheahan Diamond Literature Reference Compilation - Scientific Articles by Author for all years - J
Posted/
Published
AuthorTitleSourceRegionKeywords
DS201904-0758
2019
J.Maunder, B. Hunen, J., Bouihol, P., Magni, V.Modeling slab temperature: a reevaluation of the thermal parameter.Geochemistry, Geophysics, Geosystems, Vol. 20, 2, pp. 673-687.MantleThermometry

Abstract: We reevaluate the effects of slab age, speed, and dip on slab temperature with numerical models. The thermal parameter ? = t v sin ?, where t is age, v is speed, and ? is angle, is traditionally used as an indicator of slab temperature. However, we find that an empirically derived quantity, in which slab temperature T ? log (t?av?b) , is more accurate at depths <120 km, with the constants a and b depending on position within the slab. Shallower than the decoupling depth (~70-80 km), a~1 and b~0, that is, temperature is dependent on slab age alone. This has important implications for the early devolatilization of slabs in the hottest (youngest) cases and for shallow slab seismicity. At subarc depths (~100 km), within the slab mantle, a~1 and b~0 again. However, for the slab crust, now a~0.5 and b~1, that is, speed has the dominant effect. This is important when considering the generation of arc magmatism, and in particular, slab melting and the generation of slab?derived melange diapirs. Moving deeper into the Earth, the original thermal parameter performs well as a temperature indicator, initially in the core of the slab (the region of interest for deep water cycling). Finally, varying the decoupling depth between 40 and 100 km has a dominant effect on slab temperatures down to 140?km depth, but only within the slab crust. Slab mantle temperature remains primarily dependent on age.
DS202205-0702
2022
J. SealesLenardic, A., J. SealesInternal planetary feedbacks, mantle dynamics, and plate tectonics.Researchgate preprint Chapter from book Elsevier, March 61p. PdfMantlegeodynamics

Abstract: Isolating planetary feedbacks, and feedback analysis, are prevalent aspects of climate and Earth surface process science. An under appreciation of internal planet feedbacks, and feedback analysis for plate tectonics research, motivate this chapter. We review feedbacks that influence the Earth's thermal evolution and expand them to include magmatic history and planetary water budgets. The predictions from feedback models are shown to be consistent with petrological constraints on the Earth's cooling. From there, we isolate feedbacks that connect structural elements within the mantle dynamics and plate tectonics system. The feedbacks allow for a reciprocal causality between plates, plumes, the asthenosphere, and mantle flow patterns, with each element being co-dependent on the others. The linked elements and feedbacks define plate tectonics are part of a self-sustaining flow system that can bootstrap itself into existence. Within that framework, plate tectonics involves the co-arising of critical system factors. No single factor is the cause of another. Rather, they emerge with the links between them and the generation of functional elements coincides, within relatively narrow time windows, with the co-emergence of factors that are critical for the maintenance of the elements themselves. What emerges is not a tectonic state but a process. That is, a set of feedbacks that can transform the tectonics of a planet and/or maintain plate tectonics. The feedback functions are not permanent but can operate over extended time frames such that plate tectonics can remain stable. The nature of the feedbacks, and their stability, can be studied at various levels of detail but questions of origin can become ill-defined. Observational tests of a feedback framework for plate tectonics and mantle dynamics are presented, along with research paths that apply feedback methodology to solid planet dynamics and comparative planetology.
DS1975-1081
1979
J.C. Hill &associationJ.C. Hill &associationProposals for the Survey and Evaluation of Offshore Diamondiferous Gravel Deposits in the Hondeklipbaai Area of South Africa.Unpubl. Report., 20P.South AfricaProspecting, Exploration
DS1860-0631
1889
Jaap, A.H.Jaap, A.H.Days with Industrials. Adventures and Experiences Among Curious Industries.London: Trubner And Co., Africa, South AfricaTravelogue
DS201505-0242
2015
Jablon, M.Jablon, M., Navon, O.The role of high density Micro inclusion fluids in the growth of monocrystalline diamonds.Israel Geological Society, Abstracts 1p.Africa, Guinea, South AfricaFibrous diamonds
DS1996-0712
1996
JablonskiKamperman, M., Danyushevskey, L.V., Taylor, W., JablonskiDirect oxygen measurements of chromium rich spinel: implications for spinelstoichiometry.American Mineralogist, Vol. 81, Sept-Oct., pp. 1186-1194.AustraliaDiamond indicator spinel, Deposit -Aries, Argyle
DS1984-0118
1984
Jablonwo, J.Ashburn, A., Jablonwo, J.Japan Pushes into Diamond TurningAmerican Machinery, Vol. 128, No. 12, DECEMBER PP. 75-79.JapanIndustrial
DS1995-0800
1995
Jachens, R.C.Hildenbrand, T.G., Jachens, R.C., Simpson, R.W.Insights on lithospheric structures within the stable craton, USA based on magnetic and gravity data.Iagod Giant Ore Deposits Workshop, J. Kutina, 6p.MidcontinentCraton, Geophysics -magnetics, gravity
DS1997-0505
1997
Jachens, R.C.Hildenbrand, T.G., Jachens, R.C., Simpson, R.W.Insights on lithospheric structures within the stable craton USA, based on magnetic and gravity data.Global Tectonics and Metallogeny, Vol. 6, No. 2, March pp. 113-118.MidcontinentMantle structure, Geophysics - magnetics, gravity
DS1860-0758
1892
Jack, R.L.Jack, R.L.On the Sapphire Deposits and the Gold and Silver Mines Near west Marsfield. GilbertonQueensland Geological Survey Publn., No. 16, P. 81.Australia, QueenslandSapphire
DS1989-1406
1989
JacksonSmith, C.B., Allsopp, H.L., Garvie, O.G., Kramers, J.D., JacksonNote on the uranium-lead (U-Pb) (U-Pb) perovskite method for dating kimberlites: examples fromChemical Geology, Vol. 79, pp. 137-145South Africa, Northwest TerritoriesGeochronology, Perovskite
DS1997-1211
1997
JacksonVilleneuve, M.E., Henderson, J.R., Hrabi, R.B., Jackson2.80-2.58 Ga plutonism and volcanism in the Slave ProvinceGeological Survey of Canada (GSC) Paper, No. 1997-F, pp. 37-60.Northwest TerritoriesGeochronology, Craton - Slave
DS1997-1212
1997
JacksonVilleneuve, M.E., Henderson, J.R., Hrabi, R.B., Jackson2.70 - 2.58 Ga plutonism and volcanism in the Slave Province, District ofMackenzie, Northwest Territories.Geological Society of Canada (GSC) Paper, No. 1997-F, p. 37-60.Northwest TerritoriesGeochronology, Magma activity
DS2001-0102
2001
JacksonBelousova, E.A., Griffin, W.L., Shee, Jackson, O'ReillyTwo age populations of zircons from the Timber Creek kimberlites, as determined by laser ablation ICP MSAustralian Journal of Earth Sciences, Vol. 48, No. 5, Oct. pp. 757-766.AustraliaGeochronology, Deposit - Timber Creek
DS2002-0614
2002
JacksonGriffin, W.L., Wang, X., Jackson, Pearson, O'Reilly, XuZircon chemistry and magma mixing, SE China: in situ analysis of Hf isotopes, Tonglu and Pingtan complexes.Lithos, Vol.61, No.1-4, pp. 237-69., Vol.61, No.1-4, pp. 237-69.China, SoutheastGeochemistry - magma mixing, Geochronology
DS2002-0615
2002
JacksonGriffin, W.L., Wang, X., Jackson, Pearson, O'Reilly, XuZircon chemistry and magma mixing, SE China: in situ analysis of Hf isotopes, Tonglu and Pingtan complexes.Lithos, Vol.61, No.1-4, pp. 237-69., Vol.61, No.1-4, pp. 237-69.China, SoutheastGeochemistry - magma mixing, Geochronology
DS2002-1236
2002
JacksonPearson, N.J., Alard, O., Griffin, Jackson, O'ReillyIn situ measurement of Re Os isotopes in mantle sulfides by laser ablation multicollector inductively..Geochimica et Cosmochimica Acta, Vol. 66, 6, pp. 1037-50.Russia, Siberia, Northwest TerritoriesCraton - mass spectrometry, rhenium, osmium, Peridotites
DS2002-1685
2002
JacksonWang, X., Griffin, O'Reilly, Zhou, Xu, Jackson, PearsonMorphology and geochemistry of zircons from late Mesozoic igneous complexes in coastal SE China:Mineralogical Magazine, Vol.66,2,pp. 235-52., Vol.66,2,pp. 235-52.China, southeastPetrogenesis
DS2002-1686
2002
JacksonWang, X., Griffin, O'Reilly, Zhou, Xu, Jackson, PearsonMorphology and geochemistry of zircons from late Mesozoic igneous complexes in coastal SE China:Mineralogical Magazine, Vol.66,2,pp. 235-52., Vol.66,2,pp. 235-52.China, southeastPetrogenesis
DS200712-0204
2007
JacksonCourtier, A.M., Jackson, Lawrence, Wang, Lee, Halama, Warren, Workman, Xu, Hirschmann, Larson, Hart, Lithgo-Bertelloni, Stixrude, ChenCorrelation of seismic and petrologic thermometers suggests deep thermal anomalies beneath hotspots.Earth and Planetary Science Letters, Vol. 264, 1-2, pp. 308-316.MantleGeothermometry
DS1991-0775
1991
Jackson, .E.Jackson, .E.A user's guide to principal componentsWiley Interscience, 569p. approx. $ 70.00GlobalGeostatistics, Book Review
DS1991-0131
1991
Jackson, A.Bloxham, J., Jackson, A.Fluid flow near the surface of earth's outer coreReviews of Geophysics, Vol. 29, No. 1, February pp. 97-120GlobalEarth's core, Core/mantle
DS201509-0415
2015
Jackson, A-L.Magee, C., Mahaaj, S.M., Wrona, T., Jackson, A-L.Controls on the expression of igneous intrusions in seismic reflection data.Geosphere, Vol. 11, 4, pp. 1024-1041.MantleMagmatism

Abstract: The architecture of subsurface magma plumbing systems influences a variety of igneous processes, including the physiochemical evolution of magma and extrusion sites. Seismic reflection data provides a unique opportunity to image and analyze these subvolcanic systems in three dimensions and has arguably revolutionized our understanding of magma emplacement. In particular, the observation of (1) interconnected sills, (2) transgressive sill limbs, and (3) magma flow indicators in seismic data suggest that sill complexes can facilitate significant lateral (tens to hundreds of kilometers) and vertical (<5 km) magma transport. However, it is often difficult to determine the validity of seismic interpretations of igneous features because they are rarely drilled, and our ability to compare seismically imaged features to potential field analogues is hampered by the limited resolution of seismic data. Here we use field observations to constrain a series of novel seismic forward models that examine how different sill morphologies may be expressed in seismic data. By varying the geologic architecture (e.g., host-rock lithology and intrusion thickness) and seismic properties (e.g., frequency), the models demonstrate that seismic amplitude variations and reflection configurations can be used to constrain intrusion geometry. However, our results also highlight that stratigraphic reflections can interfere with reflections generated at the intrusive contacts, and may thus produce seismic artifacts that could be misinterpreted as real features. This study emphasizes the value of seismic data to understanding magmatic systems and demonstrates the role that synthetic seismic forward modeling can play in bridging the gap between seismic data and field observations.
DS201708-1676
2017
Jackson, C.Jackson, C.New insights into volatile-rich mantle metasomatism at the Bultfontein diamond mine, Kimberley, South Africa.11th. International Kimberlite Conference, PosterAfrica, South Africadeposit - Bultfontein
DS201709-2002
2017
Jackson, C.Jackson, C., Gibson, S.New insights into sulfur-rich mantle metasomatism at Bultfontein, Kimberley.Goldschmidt Conference, abstract 1p.Africa, South Africadeposit - Bultfontein

Abstract: Metasomatised regions of Earth’s sub-continental lithospheric mantle potentially represent a large volatile reservoir. Nevertheless, the mechanisms involved in the storage and upward transport of volatiles such as C and S, from the convecting mantle and/or subducting slabs, are poorly understood. We have carried out a systematic microanalytical study of a suite of sulfide-rich mantle peridotites from the Bultfontein diamond mine, Kimberley. EDS mapping of large (>2mm), interstitial base metal sulfides in the Bultfontein xenoliths has identified distinct Ni-rich regions (pentlandite). The Ni-rich sulfides are adjacent to olivine with Ni poor rims (<0.2 wt% NiO). Diffusion profiles between the protolith olivines and adjacent sulfides are used to estimate the timing of the S-rich metasomatic event. The presence of large unequilibrated olivine indicates that Nisulfides were introduced immediately prior to kimberlite emplacement. The calculated composition of melt in equilibrium with metasomatic clinopyroxenes in the Bultfontein sulphide-bearing peridotites shows a strong correlation to high-density carbonatitic fluids trapped in diamonds. This association is extended by the wealth of metasomatic sulfides in the Bultfontein xenoliths. Moreover, Ni-rich sulfides (~25 wt%) are the most common mineral inclusion in peridotitic diamonds, implying that diamonds crystallise from a S-saturated fluid. Many studies attribute the metasomatism at Bultfontein to silicate melts associated with the kimberlite, but we explore the possibility of metasomatism by reactive percolation of a volatile-rich agent with carbonatitic affinity. The S-rich nature of the metasomatism and the correlation with diamond high-density fluids has great implications for the transport of volatiles from the deep mantle to shallow regions of the craton.
DS201807-1510
2018
Jackson, C.A-L.Magee, C., Stevenson, C.T.E., Ebmeier, S.K., Keir, D., Hammond, J.O.S., Gottsmann, J.H., Whaler, K.A., Schofield, N., Jackson, C.A-L., Petronis, M.S., O'Driscoll, B., Morgan, J., Cruden, A., Vollgger, S.A., Dering, G., Micklethwaite, S., Jackson, M.D.Magma plumbing systems: a geophysical perspective. InSAR, GPS, GNSS, FWI, UAVsJournal of Petrology, in press available, 99p.Mantlemagmatism - geophysics

Abstract: Over the last few decades, significant advances in using geophysical techniques to image the structure of magma plumbing systems have enabled the identification of zones of melt accumulation, crystal mush development, and magma migration. Combining advanced geophysical observations with petrological and geochemical data has arguably revolutionised our understanding of, and afforded exciting new insights into, the development of entire magma plumbing systems. However, divisions between the scales and physical settings over which these geophysical, petrological, and geochemical methods are applied still remain. To characterise some of these differences and promote the benefits of further integration between these methodologies, we provide a review of geophysical techniques and discuss how they can be utilised to provide a structural context for and place physical limits on the chemical evolution of magma plumbing systems. For example, we examine how Interferometric Synthetic Aperture Radar (InSAR), coupled with Global Positioning System (GPS) and Global Navigation Satellite System (GNSS) data, and seismicity may be used to track magma migration in near real-time. We also discuss how seismic imaging, gravimetry, and electromagnetic data can identify contemporary melt zones, magma reservoirs, and, or, crystal mushes. These techniques complement seismic reflection data and rock magnetic analyses that delimit the structure and emplacement of ancient magma plumbing systems. For each of these techniques, with the addition of full-waveform inversion (FWI), the use of Unmanned Aerial Vehicles (UAVs), and the integration of geophysics with numerical modelling, we discuss potential future directions. We show that approaching problems concerning magma plumbing systems from an integrated petrological, geochemical, and geophysical perspective will undoubtedly yield important scientific advances, providing exciting future opportunities for the volcanological community.
DS201810-2331
2018
Jackson, C.G.Jackson, C.G., Gibson, S.A.Preservation of systematic Ni and Cr heterogeneity in otherwise homogeneous mantle olivine: implications for timescales of post-metasomatism re-equilibration.Lithos, Vol. 318-319. pp. 448-463.Africa, South Africadeposit - Bultfontein

Abstract: The flux of elements into Earth's sub-continental lithospheric mantle is facilitated by the passage of small-fraction melts that either crystallise new phases or react with pre-existing minerals.Metasomatised peridotite records the end product of this exchange but rarely captures the process in the act due to subsolidus re-equilibration. We present the results of a systematic investigation of a metasomatic melt channel preserved in a mantle peridotite from the Late Cretaceous Bultfontein kimberlite (Kaapvaal craton) that shows rare direct evidence of the melt-rock reaction processes. We show that the metasomatic proto-kimberlite melt underwent variable crystallisation of clinopyroxene, sulfides, phlogopite, spinel and zircon together with interaction and diffusive exchange with the surrounding olivine-rich mantle. Element profiles across large olivine porphyroclasts (Fo88) show significant core-to-rim variations in Ni (NiO?=?0.18-0.32?wt%) and Cr (Cr?=?35-60?ppm), while concentrations of all other elements (e.g. Mg, Fe, Mn, Co, V)are remarkably homogeneous. Electron backscatter diffraction analysis shows that the disequilibrium of Ni and Cr is greatest where the crystal contains large components of the [100] and [010] axes. The disequilibrium is preserved in certain orientations because diffusion of Ni and Cr in olivine is more anisotropic than Fe-Mg and Mn, and slower in the [100] and [010] directions. We present the first observations of Ni and Cr decoupling from other elements in mantle olivine and suggest that this is a consequence of: (i)changing mineral-melt concentration gradients associated with the reactive percolation of a precursory kimberlite melt; and (ii) late-stage sulfide and spinel precipitation. We use the diffusion limited re-equilibration of Ni in olivine to quantify the timing of metasomatism prior to xenolith entrainment by the host kimberlite. Our modelling indicates that reactive percolation occurred on the order of 103-105?years prior to entrainment; this provides an additional line of support for the hypothesis that a period of metasomatism by proto-kimberlite melts precedes the final kimberlite ascent to the surface. The broader implication of our finding of variable rates of minor element diffusion in natural olivine is that it highlights the importance of anisotropy and the impact of changing local concentration gradients during subsolidus re-equilibration.
DS201812-2821
2018
Jackson, C.G.Jackson, C.G., Gibson, S.A.Preservation of systematic Ni and Cr heterogeneity in otherwise homogeneous mantle olivine: implications for timescales of post-metasomatism re-equilibrium.Lithos, Vol. 318-319, pp. 448-463.Africa, South Africadeposit - Bultfontein

Abstract: The flux of elements into Earth’s sub-continental lithospheric mantle is facilitated by the passage of small-fraction melts that either crystallise new phases or react with pre-existing minerals. Metasomatised peridotite records the end product of this exchange but rarely captures the process in the act due to subsolidus re-equilibration. We present the results of a systematic investigation of a metasomatic melt channel preserved in a mantle peridotite from the Late Cretaceous Bultfontein kimberlite (Kaapvaal craton) that shows rare direct evidence of the melt-rock reaction processes. We show that the metasomatic proto-kimberlite melt underwent variable crystallisation of clinopyroxene, sulfides, phlogopite, spinel and zircon together with interaction and diffusive exchange with the surrounding olivine-rich mantle. Element profiles across large olivine porphyroclasts (Fo88) show significant core-to-rim variations in Ni (NiO = 0.18-0.32 wt.%) and Cr (Cr = 35-60 ppm), while concentrations of all other elements (e.g. Mg, Fe, Mn, Co, V) are remarkably homogeneous. Electron backscatter diffraction analysis shows that the disequilibrium of Ni and Cr is greatest where the crystal contains large components of the [100] and [010] axes. The disequilibrium is preserved in certain orientations because diffusion of Ni and Cr in olivine is more anisotropic than Fe-Mg and Mn, and slower in the [100] and [010] directions. We present the first observations of Ni and Cr decoupling from other elements in mantle olivine and suggest that this is a consequence of: (i) changing mineral-melt concentration gradients associated with the reactive percolation of a precursory kimberlite melt; and (ii) late-stage sulfide and spinel precipitation. We use the diffusion limited re-equilibration of Ni in olivine to quantify the timing of metasomatism prior to xenolith entrainment by the host kimberlite. Our modelling indicates that reactive percolation occurred on the order of 103-105 years prior to entrainment; this provides an additional line of support for the hypothesis that a period of metasomatism by proto-kimberlite melts precedes the final kimberlite ascent to the surface. The broader implication of our finding of variable rates of minor element diffusion in natural olivine is that it highlights the importance of anisotropy and the impact of changing local concentration gradients during subsolidus re-equilibration.
DS201803-0455
2018
Jackson, C.R.Jackson, C.R., Bennett, N.R., Du, Z., Cottrell, E., Fei, Y.Early episodes of high pressure core formation preserved in plume mantle.Nature , Vol. 553, 7689, pp. 491-495.Mantleplumes

Abstract: The decay of short-lived iodine (I) and plutonium (Pu) results in xenon (Xe) isotopic anomalies in the mantle that record Earth’s earliest stages of formation1,2,3,4,5,6,7,8. Xe isotopic anomalies have been linked to degassing during accretion2,3,4, but degassing alone cannot account for the co-occurrence of Xe and tungsten (W) isotopic heterogeneity in plume-derived basalts9,10 and their long-term preservation in the mantle. Here we describe measurements of I partitioning between liquid Fe alloys and liquid silicates at high pressure and temperature and propose that Xe isotopic anomalies found in modern plume rocks (that is, rocks with elevated 3He/4He ratios) result from I/Pu fractionations during early, high-pressure episodes of core formation. Our measurements demonstrate that I becomes progressively more siderophile as pressure increases, so that portions of mantle that experienced high-pressure core formation will have large I/Pu depletions not related to volatility. These portions of mantle could be the source of Xe and W anomalies observed in modern plume-derived basalts2,3,4,9,10. Portions of mantle involved in early high-pressure core formation would also be rich in FeO11,12, and hence denser than ambient mantle. This would aid the long-term preservation of these mantle portions, and potentially points to their modern manifestation within seismically slow, deep mantle reservoirs13 with high 3He/4He ratios.
DS201706-1104
2017
Jackson, C.R.M.Smye, A.J., Jackson, C.R.M., Konrad-Schnolke, M., Hesse, M.A., Parman, S.W., Shuster, D.L., Ballentine, C.J.Noble gases recycled into the mantle through cold subduction zones.Earth and Planetary Science Letters, Vol. 471, pp. 65-73.Mantlegeochemistry, water cycle

Abstract: Subduction of hydrous and carbonated oceanic lithosphere replenishes the mantle volatile inventory. Substantial uncertainties exist on the magnitudes of the recycled volatile fluxes and it is unclear whether Earth surface reservoirs are undergoing net-loss or net-gain of H2O and CO2. Here, we use noble gases as tracers for deep volatile cycling. Specifically, we construct and apply a kinetic model to estimate the effect of subduction zone metamorphism on the elemental composition of noble gases in amphibole - a common constituent of altered oceanic crust. We show that progressive dehydration of the slab leads to the extraction of noble gases, linking noble gas recycling to H2O. Noble gases are strongly fractionated within hot subduction zones, whereas minimal fractionation occurs along colder subduction geotherms. In the context of our modelling, this implies that the mantle heavy noble gas inventory is dominated by the injection of noble gases through cold subduction zones. For cold subduction zones, we estimate a present-day bulk recycling efficiency, past the depth of amphibole breakdown, of 5-35% and 60-80% for 36Ar and H2O bound within oceanic crust, respectively. Given that hotter subduction dominates over geologic history, this result highlights the importance of cooler subduction zones in regassing the mantle and in affecting the modern volatile budget of Earth's interior.
DS202012-2221
2021
Jackson, C.R.M.Jackson, C.R.M., Cottrell, E., Andrews, B.Warm and oxidizing slabs limit ingassing efficiency of nitrogen to the mantle.Earth and Planetary Letters, Vol. 553, 116515, 12p. PdfMantlenitrogen

Abstract: Nitrogen is a major and essential component of Earth's atmosphere, yet relative to other volatile elements, there are relatively few experimental constraints on the pathways by which nitrogen cycles between Earth's interior and exterior. We report mineral-melt and mineral-fluid partitioning experiments to constrain the behavior of nitrogen during slab dehydration and sediment melting processes. Experiments reacted rhyolitic melts with silicate and oxide minerals, in the presence of excess aqueous fluid, over temperatures between 725-925 °C and pressures between 0.2 and 2.3 GPa. Oxygen fugacity ranged between iron metal saturation (?NNO-5) to that in excess of primitive arc basalts (?NNO+2). Our experiments demonstrate that hydrous fluid is the preferred phase for nitrogen over minerals (biotite, K-feldspar, and amphibole) and rhyolitic melts across all conditions explored. Relatively large effects of pressure (?log()/?(GPa/K) = 761 ± 68 (1?), ?log()/?(GPa/K) = 462 ± 169) and moderate effects of oxygen fugacity (NNO = -0.20 ± 0.04, ?logNNO = -0.10 ± 0.04) modulate partitioning of nitrogen. We further document negligible partitioning effects related to mineral composition or Cl content of hydrous fluid. Of the minerals investigated, biotite has the largest affinity for N and should control the retention of N in slabs where present. Application of partitioning data to slab dehydration PT paths highlights the potential for highly incompatible behavior ( < 0.1) from the slab along warmer and oxidized (NNO+1) subduction geotherms, whereas dehydration along reduced and cooler geotherms will extract moderate amounts of nitrogen ( > 0.1). We find that slab melting is less effective at extracting N from slabs than fluid loss, at least under oxidized conditions (NNO+1). Ultimately, the conditions under which slabs lose fluid strongly affect the distribution of nitrogen between Earth's interior and exterior.
DS1859-0133
1859
Jackson, C.T.Jackson, C.T.Sur la Bornite de DahlOnega et sur Les Diamants de l'etat De Georgie.Academy of Science Paris COMPTES RENDUS, Vol. 48, PP. 850-851. ALSO American Journal of Science, N.S. 2, Vol. 27United States, Appalachia, GeorgiaDiamond Occurrence
DS201212-0361
2012
Jackson, D.Kjarsgaard, B.A., Mather, D.G., Pearson, S., Jackson, D., Crabtree, D., Creighton, S.CR-diopside and Cr-pyrope xenocryst thermobarometry revisited: applications to lithosphere studies and diamond exploration.10th. International Kimberlite Conference Feb. 6-11, Bangalore India, AbstractCanadaGeobarometry
DS1982-0290
1982
Jackson, D.E.Jackson, D.E.Petrogenesis of a shallow level kimberlite from Taughannock Creek, NewYorkMsc. Thesis University of Of Tennessee, Knoxville, Tn, 71pGlobalKimberlite, Petrology
DS1982-0291
1982
Jackson, D.E.Jackson, D.E., Hunter, R.H., Taylor, L.A.A Mesozoic Window Into the Sub-appalachian Mantle: Kimberlite from the Eastern United States.Geological Society of America (GSA), Vol. 14, No. 1-2, P. 28, (abstract.).United States, Appalachia, New YorkKimberlite, Dike, Devonian, Shale, Garnet
DS1982-0292
1982
Jackson, D.E.Jackson, D.E., Hunter, R.H., Taylor, L.A.Shallow Level Kimberlite from the Northeastern United States (us): an Unusual Mantle Sample.Eos, Vol. 63, PP. 463-464.United States, Appalachia, New YorkBlank
DS1986-0326
1986
Jackson, D.G.Haebig, A.E., Jackson, D.G.Geochemical expression of some west Australian kimberlites andlamproitesProceedings of the Fourth International Kimberlite Conference, Held Perth, Australia, No. 16, pp. 466-468AustraliaDiamond exploration
DS1970-0101
1970
Jackson, E.D.Jackson, E.D., Wright, T.L.Xenoliths in the Honolulu Volcanic Series, HawaiiJournal of Petrology, Vol. 11, P. 405.United States, HawaiiBlank
DS1989-0367
1989
Jackson, G.D.Dostal, J., Jackson, G.D., Galley, A.Geochemistry of Neohelikian Nauyat plateau basalts, Borden rift basin, northwestern Baffin Island.Canadian Journal of Earth Sciences, Vol. 26, pp. 2214-23.Northwest Territories, Baffin IslandBasalts
DS1995-0570
1995
Jackson, G.D.Frisch, T., Jackson, G.D., et al.uranium-lead (U-Pb) ages of zircon from the Kolvitsa gabbro anorthosite complex, southern Kola PeninsulaPetrology, Vol. 3, No. 3, May-June pp. 219-225RussiaGeochronology, Anorthosite
DS2000-0436
2000
Jackson, G.D.Jackson, G.D., Berman, R.G.Precambrian metamorphic and tectonic evolution of northern Baffin Island, Nunuvut Canada.Can. Mineralog., Vol. 38, No. 2, Apr. pp. 399-422.Northwest Territories, Nunavut, Baffin IslandTectonics - metamorphism
DS200612-1358
2006
Jackson, G.D.St.Onge, M.R., Jackson, G.D., Henderson, I.Geology, Baffin Island south of 70 N and east of 80 W.Geological Survey of Canada, No. 4931, 1 CD $ 9.10Canada, NunavutBedrock data
DS1992-0761
1992
Jackson, H.R.Jackson, H.R., Dickie, K., Marillier, F.A seismic reflection study of northern Baffin Bay: implication for tectonicevolutionCanadian Journal of Earth Sciences, Vol. 29, No. 11, November, pp. 2353-2369GlobalGeophysics -seismics, Tectonics
DS1994-0813
1994
Jackson, H.R.Jackson, H.R., Reid, I.Crustal thickness variations between Greenland and Ellesmere Island margins detremined from seismic...Canadian Journal of Earth Sciences, Vol. 31, pp. 1407-18.Greenland, Northwest Territories, Ellesmere IslandGeophysics - seismics, Crust
DS1990-0749
1990
Jackson, I.Jackson, I., Rudnick, R.L., O'Reilly, S.Y., Bezant, C.Measured and calculated elastic wave velocities for xenoliths from the lower crust and upper mantleTectonophysics, Vol. 174, No. 1/2, March 1, pp. 207-210GlobalMantle, Xenoliths -physics
DS1991-1424
1991
Jackson, I.Rigden, S.M., Gwanmesia, G.D., Fitzgerald, J.D., Jackson, I.Spinel elasticity and seismic structure of the transition zone of themantleNature, Vol. 354, No. 6349, Nove. 14, pp. 143-145MantleSpinels, Geophysics -seismics
DS1996-0671
1996
Jackson, I.Jackson, I.The composition of the earth's mantle: insights from laboratory measurements of seismic wave speeds.Geological Society of Australia 13th. Convention held Feb., No. 41, abstracts p.215.MantleGeophysics -seismic, Lithosphere
DS2000-0437
2000
Jackson, I.Jackson, I.Geophysics: taking the Earth's temperatureNature, Vol. 406, No. 6795, Aug. 3, p. 470.GlobalGeophysics, Geothermometry
DS2000-0545
2000
Jackson, I.Kung, J., Rogden, S.M., Jackson, I.Silicate perovskite analogue ScALO3; temperature dependence of elastic moduli.Physical Earth and Planetary Interiors, Vol. 120, No. 4, Aug. 1, pp. 299-314.GlobalPerovskite - experimental petrology
DS2001-0410
2001
Jackson, I.Gregoire, M., Jackson, I., O'Reilly, S.Y., Cottin, J.Y.The lithospheric mantle beneath Kerguelen Islands: petrological and petrophysical characteristics....Contributions to Mineralogy and Petrology, Vol. 142, No. 2, Nov. pp. 244-59.Indian Ocean, Kerguelen IslandsMantle mafic rock types - correlation with profiles, Geophysics - seismics
DS200412-0535
2004
Jackson, I.Faul, U., Jackson, I., Fitzgerald, J.Viscoelasticity of olivine and implications for the upper mantle.Lithos, ABSTRACTS only, Vol. 73, p. S33. abstractUnited States, New MexicoSan Carlos olivine
DS200512-0280
2005
Jackson, I.Faul, U.H., Jackson, I.The seismological signature of temperature and grain size variations in the upper mantle.Earth and Planetary Science Letters, Vol. 234, 1-2, pp. 119-134.MantleGeophysics - seismics
DS200612-0816
2006
Jackson, I.Liebermann, R.C., Kung, J., Li, B., Jackson, I.Elastic properties of pyroxene polymorphs of MgSiO3 and implications for seismic models and discontinuities in the Earth's upper mantle.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 18, abstract only.MantleGeophysics - seismic
DS201804-0681
2018
Jackson, I.Cline, C.J. II, Faul, U.H., David, E.C., Berry, A.J., Jackson, I.Redox influenced seismic properties of upper mantle olivine.Nature, Vol. 555, March 15, pp. 255-258.Mantlegeophysics - seismics

Abstract: Lateral variations of seismic wave speeds and attenuation (dissipation of strain energy) in the Earth’s upper mantle have the potential to map key characteristics such as temperature, major-element composition, melt fraction and water content1,2,3. The inversion of these data into meaningful representations of physical properties requires a robust understanding of the micromechanical processes that affect the propagation of seismic waves2,3. Structurally bound water (hydroxyl) is believed to affect seismic properties2,3 but this has yet to be experimentally quantified. Here we present a comprehensive low-frequency forced-oscillation assessment of the seismic properties of olivine as a function of water content within the under-saturated regime that is relevant to the Earth’s interior. Our results demonstrate that wave speeds and attenuation are in fact strikingly insensitive to water content. Rather, the redox conditions imposed by the choice of metal sleeving, and the associated defect chemistry, appear to have a substantial influence on the seismic properties. These findings suggest that elevated water contents are not responsible for low-velocity or high-attenuation structures in the upper mantle. Instead, the high attenuation observed in hydrous and oxidized regions of the upper mantle (such as above subduction zones) may reflect the prevailing oxygen fugacity. In addition, these data provide no support for the hypothesis whereby a sharp lithosphere-asthenosphere boundary is explained by enhanced grain boundary sliding in the presence of water.
DS1989-0404
1989
Jackson, J.England, P., Jackson, J.Active deformation of the continentsAnnual Rev. Earth. Planet. Sci, Vol. 17, pp. 197-226GlobalTectonics, Mantle
DS1993-0727
1993
Jackson, J.Jackson, J., Blenkinsop, T.The Malawi Earthquake of March 10, 1989: deep faulting within the East African Rift systemTectonics, Vol. 12, No. 5, Oct. pp. 1131-39.East Africa, MalawiTectonics, Rifting
DS2002-0755
2002
Jackson, J.Jackson, J.Faulting, flow and the strength of the continental lithosphereInternational Geology Review, Vol. 44, 1, pp. 39-61.India, China, TibetTectonics - structure
DS2002-0756
2002
Jackson, J.Jackson, J.Strength of the continental lithosphere: time to abandon the jelly sandwich?Gsa Today, Sept. pp. 4-9.India, China, TibetTectonics, geodynamics, lithosphere
DS2002-1033
2002
Jackson, J.McKenzie, D., Jackson, J.Conditions for flow in the continental crustTectonics, Vol. 21, No. 6, 10.1029/2001TC001394MantleTectonics, Heat flow
DS200512-0470
2005
Jackson, J.Jackson, J.Mountain roots and the survival of cratons.Astronomy and Geophysics, Vol. 46, 2, pp. 2.33-2.36.MantleCraton
DS200512-0705
2005
Jackson, J.McKenzie, D., Jackson, J., Priestley, K.Thermal structure of oceanic and continental lithosphere.Earth and Planetary Science Letters, Vol. 233, 3-4, May 15, pp. 337-349.Mantle, CanadaGeothermometry, mantle rheology, heat flow
DS200712-0292
2006
Jackson, J.Emmerson, B., Jackson, J., McKensie, D., Priestley, K.Seismicity, structure and rheology of the lithosphere in the Lake Baikal region.Geophysical Journal International, Vol. 167, 3, Dec. 1, pp. 1233-1272.RussiaGeophysics - seismics
DS200812-0513
2008
Jackson, J.Jackson, J., McKenzie, D., Priestley, K., Emmerson, B.New views on the structure and rheology of the lithosphere.Journal Geological Society of London, Vol. 165, 2, pp. 453-466.MantleTectonics
DS200812-0923
2008
Jackson, J.Priestly, K., Jackson, J., McKenzie, D.Lithospheric structure and deep earthquakes beneath India, the Himalaya and southern Tibet.Geophysical Journal International, Vol. 172, 1, pp. 345-362.IndiaGeophysics - seismics
DS201312-0044
2013
Jackson, J.Ayuso, R., Tucker, R., Peters, S., Foley, N., Jackson, J., Robinson, S., Bove, M.Preliminary radiogenic isotope study on the origin of the Khanneshin carbonatite complex, Helmand Province, Afghanistan.Journal of Geochemical Exploration, Vol. 133, pp. 6-14.AfghanistanCarbonatite
DS202202-0195
2022
Jackson, J.Jackson, J., McKenzie, D.The exfoliation of cratonic Australia in earthquakes.Earth and planetary Science Letters, Vol. 578, 117305, 11p. PdfAustraliacratons

Abstract: The cratonic shield system of central and western Australia, with its lithosphere up to 200 km thick, is geologically similar to other ancient, stable continental interiors. But since 1968 it has experienced a number of moderate-sized (5.0-6.6) earthquakes characterised by the extreme shallowness of their sources (the deepest is 8 km and most are shallower than 4 km). At least 11 of these have produced co-seismic faulting, often very long compared to their depth, with typically no evidence of previous movement on those faults in either the local geomorphology or paleoseismological trenching. Other earthquakes show that cratonic Australia, like other shield regions, has a seismogenic layer about 30-40 km thick, but the intense very shallow seismicity in the region of thickest lithosphere stands out and is unusual. A clue to the origin of these shallow earthquakes lies in their association with some of the largest continental gravity anomalies outside the forelands of young orogenic belts, yet in essentially flat topography. The wavelength of the gravity anomalies (?240 km) is large compared with the seismogenic thickness (?30 km) of the lithosphere, and their amplitude is ?50 mGals. These anomalies need stresses to support them, which can be estimated by a simple model of a flexed elastic plate that reproduces the essential features of the earthquakes, including their focal mechanisms and shallow depth limit. The model shows that the maxima of the compressive stress occur beneath the maxima and minima of the gravity, on the upper and lower boundaries of the layer respectively. Perhaps surprisingly, the magnitude of such stresses is considerably greater than most estimates of the regional stress within plates. The maxima of the shear stress occur on planes with dips of 45°. The locations and mechanisms of the earthquakes show the same features. We conclude that the earthquakes release stored elastic stresses in an exfoliation process, perhaps activated by a reduction in strength through weathering, erosion or some other process.
DS1984-0373
1984
Jackson, J.A.Jackson, J.A.Carbon: Pencil Lead and GemsEarth Scince., Vol. 37, No. 2, SUMMER PP. 16-18.GlobalDiamonds
DS1995-0119
1995
Jackson, J.A.Bates, R.L., Jackson, J.A.Glossary of geology on CD-ROMAmerican Geological Institute, GlobalBook -CD ROM., Glossary
DS2000-0606
2000
Jackson, J.A.Maggi, A., Jackson, J.A., McKenszie, D., Priestley, K.Earthquake focal depths, effective elastic thickness and the strength of the continental lithosphere.Geology, Vol. 28, No. 6, June pp. 495-8.MantleEarthquakes - crustal thickness, Seismogenic crust
DS2002-0757
2002
Jackson, J.A.Jackson, J.A.Using earthquakes for continental tectonic geologyInternational Geophysics Series, Vol. 81, A, pp. 491-504.MantleTectonics
DS201112-0219
2011
Jackson, J.A.Craig, T.J., Jackson, J.A., Priestley, K., McKenzie, D.Earthquake distribution patterns in Africa: their relationship to variations in lithospheric and geological structure, and their rheological implicationGeophysical Journal International, Vol. 185, 1, pp. 403-404.AfricaGeophysics - seismics
DS200712-0474
2007
Jackson, J.M.Jackson, J.M., Sturhahn, W., Lerche, M., Li, J.Electronic structure of iron in aluminous ferromagnesium silicate perovskite under lower mantle conditions.Frontiers in Mineral Sciences 2007, Joint Meeting of Mineralogical societies Held June 26-28, Cambridge, Abstract Volume p.146.MantlePerovskite
DS200712-0475
2007
Jackson, J.M.Jackson, J.M., Sturhahn, W., Lerche, M., Li, J.Electronic structure of iron in aluminous ferromagnesium silicate perovskite under lower mantle conditions.Frontiers in Mineral Sciences 2007, Joint Meeting of Mineralogical societies Held June 26-28, Cambridge, Abstract Volume p.146.MantlePerovskite
DS200912-0802
2008
Jackson, J.M.Wagner, L.B., Anderson, M.L., Jackson, J.M., Beck, S.L., Zandt,G.Seismic evidence for orthopyroxene enrichment in the continental lithosphere.Geology, Vol. 36, 12, Dec. pp. 936=938.MantleGeophysics - seismics
DS201312-0895
2013
Jackson, J.M.Sun, D., Helmberger, D.V., Jackson, J.M., Clayton, R.W.Rolling hills on the core-mantle boundary.Earth and Planetary Science Letters, Vol. 361, pp. 333-342.MantleCMB - structure
DS201606-1118
2016
Jackson, J.M.Solomatova, N.V., Jackson, J.M., Sturhahn, W., Wicks, J.K., Zhao, J., Toellner, T.S., Kalkan, B., Steinhardt, W.M.Equation of state and spin crossover of ( Mg,Fe)O at high pressure, with implications for explaining topographic relief at the core mantle boundary.American Mineralogist, Vol. 101, 5, pp. 1084-1093.MantleCore, mantle boundary
DS201709-2071
2017
Jackson, J.M.Wicks, J.K., Jackson, J.M., Struhahn, W., Zhang, D.Sound velocity and sensity of magnesiowustites: implications for ultralow velocity zone topography.Geophysics Research Letters, Vol. 44, 5, pp. 2148-2158.Mantlegeophysics - seismics

Abstract: We explore the effect of Mg/Fe substitution on the sound velocities of iron-rich (Mg1 ? xFex)O, where x = 0.84, 0.94, and 1.0. Sound velocities were determined using nuclear resonance inelastic X-ray scattering as a function of pressure, approaching those of the lowermost mantle. The systematics of cation substitution in the Fe-rich limit has the potential to play an important role in the interpretation of seismic observations of the core-mantle boundary. By determining a relationship between sound velocity, density, and composition of (Mg,Fe)O, this study explores the potential constraints on ultralow-velocity zones at the core-mantle boundary.
DS201810-2313
2018
Jackson, J.M.Finkelstein, G.J., Jackson, J.M., Said, A., Alatas, A., Leu, B.M., Sturhahn, W., Toellner, T.S.Strongly anisotropic magnesiowustite in Earth's lower mantle. Journal of Geophysical Research Solid Earth, doi.org/10.1029/ 2017JB015349Mantlecore mantle boundary

Abstract: The juxtaposition of a liquid iron?dominant alloy against a mixture of silicate and oxide minerals at Earth's core?mantle boundary is associated with a wide range of complex seismological features. One category of observed structures is ultralow?velocity zones, which are thought to correspond to either aggregates of partially molten material or solid, iron?enriched assemblages. We measured the phonon dispersion relations of (Mg,Fe) O magnesiowüstite containing 76 mol % FeO, a candidate ultralow?velocity zone phase, at high pressures using high?energy resolution inelastic X?ray scattering. From these measurements, we find that magnesiowüstite becomes strongly elastically anisotropic with increasing pressure, potentially contributing to a significant proportion of seismic anisotropy detected near the base of the mantle.
DS201904-0771
2019
Jackson, J.M.Reali, R., Jackson, J.M., Van Orman, J., Bower, D.J., Carrez, P., Cordier, P.Modeling viscosity of ( Mg, Fe)O at lowermost mantle conditions.Physics of the Earth and Planetary Interiors, Vol. 287, pp. 65-75.Mantlecore-mantle boundary

Abstract: The viscosity of the lower mantle results from the rheological behavior of its two main constituent minerals, aluminous (Mg,Fe)SiO3 bridgmanite and (Mg,Fe)O ferropericlase. Understanding the transport properties of lower mantle aggregates is of primary importance in geophysics and it is a challenging task, due to the extreme time-varying conditions to which such aggregates are subjected. In particular, viscosity is a crucial transport property that can vary over several orders of magnitude. It thus has a first-order control on the structure and dynamics of the mantle. Here we focus on the creep behavior of (Mg,Fe)O at the bottom of the lower mantle, where the presence of thermo-chemical anomalies such as ultralow-velocity zones (ULVZ) may significantly alter the viscosity contrast characterizing this region. Two different iron concentrations of (Mg1-xFex)O are considered: one mirroring the average composition of ferropericlase throughout most of the lower mantle (x?=?0.20) and another representing a candidate magnesiowüstite component of ULVZs near the base of the mantle (x?=?0.84). The investigated pressure-temperature conditions span from 120?GPa and 2800?K, corresponding to the average geotherm at this depth, to core-mantle boundary conditions of 135?GPa and 3800?K. In this study, dislocation creep of (Mg,Fe)O is investigated by dislocation dynamics (DD) simulations, a modeling tool which considers the collective motion and interactions of dislocations. To model their behavior, a 2.5 dimensional dislocation dynamics approach is employed. Within this method, both glide and climb mechanisms can be taken into account, and the interplay of these features results in a steady-state condition. This allows the retrieval of the creep strain rates at different temperatures, pressures, applied stresses and iron concentrations across the (Mg,Fe)O solid solution, providing information on the viscosity for these materials. A particularly low viscosity is obtained for magnesiowüstite with respect to ferropericlase, the difference being around 10 orders of magnitude. Thus, the final section of this work is devoted to the assessment of the dynamic implications of such a weak phase within ULVZs, in terms of the viscosity contrast with respect to the surrounding lowermost mantle.
DS1975-0106
1975
Jackson, K.C.Howard, J.M., Jackson, K.C.Petrography of the Potash Sulfur Springs Intrusion, Garlandcounty, Arkansaw.Geological Society of America (GSA), Vol. 7, No. 2, PP. 173-174. (abstract.).United States, Gulf Coast, Arkansas, Garland CountyPetrography
DS1975-0604
1977
Jackson, K.C.Robison, E.C., Steele, K.F., Jackson, K.C.Geochemistry of Lamprophyric Rocks, Eastern Ouachita Mountains, Arkansaw.Geological Society of America (GSA), Vol. 9, No. 1, PP. 69-70.United States, Oklahoma, Gulf Coast, Arkansas, Garland CountyPetrology, Geochemistry
DS1975-0769
1978
Jackson, K.C.Jackson, K.C.Arkansaw Syenites, Fenitized Crustal Material?Geological Society of America (GSA), Vol. 10, No. 1, PP. 7-8.United States, Gulf Coast, Arkansas, Hot Spring County, Garland CountyMagnet Cove, Potash Sulfur Springs, Petrology
DS1975-1232
1979
Jackson, K.C.Steele, K.F., Jackson, K.C., Van buren, W.Geochemical Comparison of Arkansaw SyeniteGeological Society of America (GSA), Vol. 11, No. 2, P. 166. (abstract.).United States, Gulf Coast, Arkansas, Garland County, Hot Spring CountyMagnet Cove, Potash Sulfur Springs, Geochemistry
DS1975-0297
1976
Jackson, K.D.Jackson, K.D., Steele, K.F.New Dat a on Some Arkansaw Igneous RocksGeological Society of America (GSA), Vol. 8, No. 1, PP. 25-26. (abstract.).United States, Gulf Coast, Arkansas, Garland CountyGeochemistry
DS201603-0396
2016
Jackson, K.G.Long, M.D., Jackson, K.G., McNamara, J.F.SKS splitting beneath transportable array stations in eastern North America and the signature of past lithospheric deformation.Geochemistry, Geophysics, Geosystems: G3, Vol. 17, 1, pp. 2-15.United StatesGeophysics - seismics

Abstract: Seismic anisotropy in the upper mantle beneath continental interiors is generally complicated, with contributions from both the lithosphere and the asthenosphere. Previous studies of SKS splitting beneath the eastern United States have yielded evidence for complex and laterally variable anisotropy, but until the recent arrival of the USArray Transportable Array (TA) the station coverage has been sparse. Here we present SKS splitting measurements at TA stations in eastern North America and compare the measured fast directions with indicators such as absolute plate motion, surface geology, and magnetic lineations. We find few correlations between fast directions and absolute plate motion, except in the northeastern U.S. and southern Canada, where some stations exhibit variations in apparent splitting with backazimuth that would suggest multiple layers of anisotropy. A region of the southeastern U.S. is dominated by null SKS arrivals over a range of backazimuths, consistent with previous work. We document a pattern of fast directions parallel to the Appalachian mountain chain, suggesting a contribution from lithospheric deformation associated with Appalachian orogenesis. Overall, our measurements suggest that upper mantle anisotropy beneath the eastern United States is complex, with likely contributions from both asthenospheric and lithospheric anisotropy in many regions.
DS1950-0013
1950
Jackson, L.Belshaw, J.P., Jackson, L.Mining for Diamonds, Sapphires and Emeralds in Northern New south Wales.Armidale: New England University Reg. Res., No. 2, (UNPUBL.).AustraliaDiamond
DS1970-0940
1974
Jackson, M.Jackson, M.Gems, the Beautiful InvestmentDallas: R. Larry Kuehn Prod., 52P.GlobalKimberlite
DS1975-0751
1978
Jackson, M.Van De Graaff, W.J.E., Crowe, R.W.A., Bunting, J.A., Jackson, M.Relic Early Cainozoic Drainages in Arid Western AustraliaZeitschr. Geomorph., Vol. 21, No. 4, PP. 379-400.Australia, Western AustraliaDiamond, Geomorphology
DS1986-0392
1986
Jackson, M.Jackson, M., Van der Voo, R.A paleomagnetic estimate of the age and thermal history of the Kentland Indiana cryptoexplosion structureJournal of Geology, Vol. 94, No. 5, September pp. 713-724IndianaPaleomagnetics, Geophysics, Thermobarometry
DS1989-0967
1989
Jackson, M.McCabe, C., Jackson, M., Suffer, B.Regional patterns of magnetite authigenesis in the Appalachian basin:implications for the mechanism of late Paleozoic remagnetizationJournal of Geophys. Research, Vol. 94, No. B8, August 10, pp. 10, 429-10, 443AppalachiaGeophysics, Paleomagnetism
DS1991-0776
1991
Jackson, M.Jackson, M.Anisotropy of magnetic remanence- a brief review of mineralogical physical origins and geological applications, and comparison with susceptibilityanisotropPure and Applied Geophysics, Vol. 136, No. 1, May pp. 1-28GlobalReview, Anisotropy
DS1994-0814
1994
Jackson, M.Jackson, M.Mining on the edge of Yellowstone Park... extracted from an environmental management study.Crs Perspectives, No. 48, February pp. 2-15Montana, Ontario, Quebec, BrazilEnvironmental study, gold, Deposit -Mineral Hill
DS2003-0626
2003
Jackson, M.Iverson, N.R., Cohen, D., Hooyer, T.S., Fischer, U.H., Jackson, M., Moore, P.L.Effects of basal debris on glacier flowScience, No. 5629, July 4, pp. 81-83.GlobalGeomorphology
DS200412-0884
2003
Jackson, M.Iverson, N.R., Cohen, D., Hooyer, T.S., Fischer, U.H., Jackson, M., Moore, P.L., Lappegard, G., Kohler, J.Effects of basal debris on glacier flow.Science, No. 5629, July 4, pp. 81-83.TechnologyGeomorphology
DS200512-0286
2005
Jackson, M.Ferr, E.C., Tikoff, B., Jackson, M.The magnetic anistropy of mantle peridotites: examples from the Twin Sisters dunite, Washington.Tectonophysics, Vol. 398, 3-4, pp. 141-166.United States, WashingtonPeridotite - not specific to diamonds
DS200512-0289
2005
Jackson, M.Ferre, E.C., Tikoff, B., Jackson, M.The magnetic anisotropy of mantle peridotites: examples from the Twin Sisters dunite, Washington.Tectonophysics, Vol. 398, 3-4, April 13, pp. 141-166.United States, WashingtonGeophysics - AMS magnetometer, not specific to diamond
DS202202-0217
2022
Jackson, M.Sparks, R.S.J., Blundym J.D., Cashman, K.V., Jackson, M., Rust, A., Wilson, C.J.N.Large silicic magma bodies and very large magnitude explosive eruptions. *** not specific to diamondsBulletin of Volcanology, Vol. 84, 8, 6p. PdfMantlemagmatism

Abstract: Over the last 20 years, new concepts have emerged into understanding the processes that lead to build up to large silicic explosive eruptions based on integration of geophysical, geochemical, petrological, geochronological and dynamical modelling. Silicic melts are generated within magma systems extending throughout the crust by segregation from mushy zones. Segregated melt layers become unstable and can assemble into ephemeral upper crustal magma chambers rapidly prior to eruption. In the next 10 years, we can expect major advances in dynamical models as well as in analytical and geophysical methods, which need to be underpinned in field research.
DS201312-0117
2013
Jackson, M.A.Cabral, R.A., Jackson, M.A., Rose-Kaga, E.F., Koga, K.T., Whitehouse, MJ., Antonelli, M.A., Farquhar, J., Day, J.M.D., Hauri, E.H.Anomalous sulphur isotopes in plume lavas reveal deep mantle storage of Archean crust.Nature, Vol. 496, April 25, pp. 490-493.Mantle, Cook IslandsSubduction
DS1991-1663
1991
Jackson, M.C.Stone, D., Kamineni, D.C., Jackson, M.C.Geology of the Atikokan areaGeological Association of Canada (GAC) Annual Meeting held Toronto May 1991, Guidebook, No. A7, 27pOntarioStructure, Steep Rock Group
DS1992-1483
1992
Jackson, M.C.Stone, D., Kamineni, D.C., Jackson, M.C.Precambrian geology of the Atikokan area, northwestern OntarioGeological Survey of Canada, Bulletin. No. 405, 106p. $ 23.95OntarioAtikokan area, Precambrian geology
DS201212-0687
2012
Jackson, M.D.Solano, J.M.S., Jackson, M.D., Sparks, R.S.J., Blundy, J.D., Annen, C.Melt segregation in deep crustal hot zones: a mechanism for chemical differentiation, crustal assimilation and the formation of evolved magmas.Journal of Petrology, Vol. 53, 10, pp. 1999-2026.MantleHotspots, magmatism
DS201807-1510
2018
Jackson, M.D.Magee, C., Stevenson, C.T.E., Ebmeier, S.K., Keir, D., Hammond, J.O.S., Gottsmann, J.H., Whaler, K.A., Schofield, N., Jackson, C.A-L., Petronis, M.S., O'Driscoll, B., Morgan, J., Cruden, A., Vollgger, S.A., Dering, G., Micklethwaite, S., Jackson, M.D.Magma plumbing systems: a geophysical perspective. InSAR, GPS, GNSS, FWI, UAVsJournal of Petrology, in press available, 99p.Mantlemagmatism - geophysics

Abstract: Over the last few decades, significant advances in using geophysical techniques to image the structure of magma plumbing systems have enabled the identification of zones of melt accumulation, crystal mush development, and magma migration. Combining advanced geophysical observations with petrological and geochemical data has arguably revolutionised our understanding of, and afforded exciting new insights into, the development of entire magma plumbing systems. However, divisions between the scales and physical settings over which these geophysical, petrological, and geochemical methods are applied still remain. To characterise some of these differences and promote the benefits of further integration between these methodologies, we provide a review of geophysical techniques and discuss how they can be utilised to provide a structural context for and place physical limits on the chemical evolution of magma plumbing systems. For example, we examine how Interferometric Synthetic Aperture Radar (InSAR), coupled with Global Positioning System (GPS) and Global Navigation Satellite System (GNSS) data, and seismicity may be used to track magma migration in near real-time. We also discuss how seismic imaging, gravimetry, and electromagnetic data can identify contemporary melt zones, magma reservoirs, and, or, crystal mushes. These techniques complement seismic reflection data and rock magnetic analyses that delimit the structure and emplacement of ancient magma plumbing systems. For each of these techniques, with the addition of full-waveform inversion (FWI), the use of Unmanned Aerial Vehicles (UAVs), and the integration of geophysics with numerical modelling, we discuss potential future directions. We show that approaching problems concerning magma plumbing systems from an integrated petrological, geochemical, and geophysical perspective will undoubtedly yield important scientific advances, providing exciting future opportunities for the volcanological community.
DS201901-0042
2018
Jackson, M.D.Jackson, M.D., Blundy, J., Sparks, R.S.J. Chemical differentiation, cold storage and remobilization of magma in the Earth's crust.Nature, Vol. 564, pp. 405-409.Mantlemagmatism

Abstract: The formation, storage and chemical differentiation of magma in the Earth’s crust is of fundamental importance in igneous geology and volcanology. Recent data are challenging the high-melt-fraction ‘magma chamber’ paradigm that has underpinned models of crustal magmatism for over a century, suggesting instead that magma is normally stored in low-melt-fraction "mush reservoirs". A mush reservoir comprises a porous and permeable framework of closely packed crystals with melt present in the pore space1,10. However, many common features of crustal magmatism have not yet been explained by either the ‘chamber’ or ‘mush reservoir’ concepts. Here we show that reactive melt flow is a critical, but hitherto neglected, process in crustal mush reservoirs, caused by buoyant melt percolating upwards through, and reacting with, the crystals. Reactive melt flow in mush reservoirs produces the low-crystallinity, chemically differentiated (silicic) magmas that ascend to form shallower intrusions or erupt to the surface. These magmas can host much older crystals, stored at low and even sub-solidus temperatures, consistent with crystal chemistry data. Changes in local bulk composition caused by reactive melt flow, rather than large increases in temperature, produce the rapid increase in melt fraction that remobilizes these cool- or cold-stored crystals. Reactive flow can also produce bimodality in magma compositions sourced from mid- to lower-crustal reservoirs. Trace-element profiles generated by reactive flow are similar to those observed in a well studied reservoir now exposed at the surface. We propose that magma storage and differentiation primarily occurs by reactive melt flow in long-lived mush reservoirs, rather than by the commonly invoked process of fractional crystallization in magma chambers.
DS2000-0438
2000
Jackson, M.G.Jackson, M.G., Ihinger, P.D.Carbonatite expulsion from a lamprophyre: an integrated geochemical study of dike wall rock interaction.Geological Society of America (GSA) Abstracts, Vol. 32, No. 7, p.A-436.GlobalCarbonatite
DS200712-0862
2007
Jackson, M.G.Putirka, K.D., Perfit, M., Ryerson, F.J., Jackson, M.G.Ambient and excess mantle temperatures, olivine thermometry and active vs. passive upwelling.Chemical Geology, Vol. 241, 3-4, pp. 177-206.MantleGeothermometry
DS201112-0131
2011
Jackson, M.G.Cabral, R.A., Jackson, M.G., Rose-Koga, E.F., Fay, J.M.D., Shimizu, N.Volatile and trace element abundances in HIMU melt inclusions.Goldschmidt Conference 2011, abstract p.610.Polynesia, Cook IslandsWater, carbonatite
DS201112-0144
2011
Jackson, M.G.Carlson, R.W., Jackson, M.G.Implications of a non-chrondritic primitive mantle for chemical geodynamics.Goldschmidt Conference 2011, abstract p.624.Canada, Nunavut, Baffin IslandTrace element characteristics
DS201112-0469
2011
Jackson, M.G.Jackson, M.G., Carlson, R.W.A new starting point for the mantle's geochemical reservoirs.Goldschmidt Conference 2011, abstract p.1093.MantleGeochemistry
DS201511-1845
2015
Jackson, M.G.Jellinek, A.M., Jackson, M.G.Connections between bulk composition, geodynamics and habitability of Earth.Nature Geoscience, Vol. 8, pp. 587-593.MantleGeodynamics

Abstract: The bulk composition of the silicate part of Earth has long been linked to chondritic meteorites. Ordinary chondrites — the most abundant meteorite class — are thought to represent planetary building materials. However, a landmark discovery showed that the 142Nd/144Nd ratio of the accessible parts of the modern terrestrial mantle on Earth is greater than that of ordinary chondrites. If Earth was derived from these precursors, mass balance requires that a missing reservoir with 142Nd/144Nd lower than ordinary chondrites was isolated from the accessible mantle within 20 to 30 million years of accretion. This reservoir would host the equivalent of the modern continents' budget of radioactive heat-producing elements (uranium, thorium and potassium), yet has not been discovered. We argue that this reservoir could have been lost to space by ablation from early impactors. If so, Earth's radiogenic heat generation is between 18 and 45% lower than estimates based on a chondritic composition. Calculations of Earth's thermal history that incorporate such reduced radiogenic heating are consistent with a transition to the current plate tectonic mode in the past 2.5 billion years or so, a late onset of the dynamo and an evolving rate of volcanic outgassing consistent with Earth's long-term habitable climate. Reduced heat production compared with Venus and Mars could also explain aspects of the differences between the current climatic regimes of these planets and Earth.
DS201606-1110
2016
Jackson, M.G.Rizo, H., Walker, R.J., Carlson, R.W., Horan, M.F., Mukhopadhyay, S., Manthos, V., Francis, D., Jackson, M.G.Preservation of Earth forming events in the tungsten isotopic composition of modern flood basalts…… ancient rocksScience, Vol. 352, no. 6287, May 13, pp. 809-812.Canada, Nunavut, Baffin IslandGeochronology

Abstract: How much of Earth's compositional variation dates to processes that occurred during planet formation remains an unanswered question. High-precision tungsten isotopic data from rocks from two large igneous provinces, the North Atlantic Igneous Province and the Ontong Java Plateau, reveal preservation to the Phanerozoic of tungsten isotopic heterogeneities in the mantle. These heterogeneities, caused by the decay of hafnium-182 in mantle domains with high hafnium/tungsten ratios, were created during the first ~50 million years of solar system history, indicating that portions of the mantle that formed during Earth’s primary accretionary period have survived to the present
DS201703-0409
2017
Jackson, M.G.Jackson, M.G., Konter, J.G., Becker, T.W.Primordial helium entrained by the hottest mantle plumes.Nature Geoscience, Jan. 7, 1p. PreviewEurope, IcelandHot spots

Abstract: Helium isotopes provide an important tool for tracing early-Earth, primordial reservoirs that have survived in the planet’s interior1, 2, 3. Volcanic hotspot lavas, like those erupted at Hawaii and Iceland, can host rare, high 3He/4He isotopic ratios (up to 50 times4 the present atmospheric ratio, Ra) compared to the lower 3He/4He ratios identified in mid-ocean-ridge basalts that form by melting the upper mantle (about 8Ra; ref. 5). A long-standing hypothesis maintains that the high-3He/4He domain resides in the deep mantle6, 7, 8, beneath the upper mantle sampled by mid-ocean-ridge basalts, and that buoyantly upwelling plumes from the deep mantle transport high-3He/4He material to the shallow mantle beneath plume-fed hotspots. One problem with this hypothesis is that, while some hotspots have 3He/4He values ranging from low to high, other hotspots exhibit only low 3He/4He ratios. Here we show that, among hotspots suggested to overlie mantle plumes9, 10, those with the highest maximum 3He/4He ratios have high hotspot buoyancy fluxes and overlie regions with seismic low-velocity anomalies in the upper mantle11, unlike plume-fed hotspots with only low maximum 3He/4He ratios. We interpret the relationships between 3He/4He values, hotspot buoyancy flux, and upper-mantle shear wave velocity to mean that hot plumes—which exhibit seismic low-velocity anomalies at depths of 200 kilometres—are more buoyant and entrain both high-3He/4He and low-3He/4He material. In contrast, cooler, less buoyant plumes do not entrain this high-3He/4He material. This can be explained if the high-3He/4He domain is denser than low-3He/4He mantle components hosted in plumes, and if high-3He/4He material is entrained from the deep mantle only by the hottest, most buoyant plumes12. Such a dense, deep-mantle high-3He/4He domain could remain isolated from the convecting mantle13, 14, which may help to explain the preservation of early Hadean (>4.5 billion years ago) geochemical anomalies in lavas sampling this reservoir1, 2, 3.
DS201808-1780
2018
Jackson, M.G.Putirka, K., Tao, Y., Hari, K.R., Perfit, M., Jackson, M.G., Arevalo, Jr. R.The mantle source of thermal plumes: trace and minor element & major oxides of primitive liquids ( and why olivine compositions don't matter).minoscam.org, doi.org/10.2138/am-2018-6192 59p.Mantleforsterite

Abstract: We estimate the mantle source compositions for mantle plumes, and by implication Earth’s lower mantle, by: (a) measuring trace (e.g, Sc, V, Cu) and minor (e.g., Ca, Mn, Ni) element concentrations of high forsterite olivine grains from several plume localities, (b) estimating the parent liquid compositions from which they crystallized, (c) calculating mantle potential temperatures and degrees of partial melting and (d) estimating trace element compositions of depleted and enriched mantle sources. Our sample set includes two continental flood basalt provinces (Emeishan and Deccan), a flood basalt that erupted in a continental rift setting (Baffin Island), our type example of a thermal mantle plume (Hawaii) and lavas from the Siqueiros Transform at the East Pacific Rise, which represent the mid-ocean ridge system. We also present olivine compositions for the peridotite xenoliths from Kilbourne Hole, New Mexico, USA, which are commonly used as primary and secondary analytical standards. We find that trace elements in lava-hosted olivine grains are too far removed from their mantle source to provided anything but greatly hindered views of such. Olivine compositions reflect not only evolving liquid compositions (including partial melting conditions and later fractionation), but also evolving Ol+liq partition coefficients, which mostly increase with decreasing T during crystallization. Mantle compositions, delimited by maximum forsterite contents and estimates of parental magmas (and experimentally determined partition coefficients) indicate that our selected plumes reflect some combination of (1) a depleted mantle source that is quite similar to that obtained by other methods, and (2) a variably enriched plume source that is more enriched than current estimates of pyrolite. The enriched plume mantle sources can be explained remarkably well as a mixture of subducted mid-ocean ridge basalt (MORB; Gale et al. 2013) and depleted MORB mantle (DM; Salters and Stracke 2004), with MORB:DM ratios of 1:5 to 1:4. These ratios are most sensitive to estimates of melt fraction where plume parental magmas are last equilibrated with their mantle source, but are nonetheless consistent across a wide range of chemically very different elements, and estimates of MORB and DM obtained by very different means. Baffin Island is of particular interest. Like prior studies, we verify a high mantle potential temperature (Tp) of 1630oC (compared to Tp = 1320-1420oC for MORB from Cottrell and Kelley 2011 for Ol of Fo89.3-91.4). The Baffin source is also within error the same as DM with respect to trace elements, although still isotopically distinct; Baffin appears to be sourced in something that is akin to DM that lies at the base of the mantle, where plumes acquire their excess heat. Thus while part of our analysis supports the concept of a "slab graveyard" at the bottom of the lower mantle (e.g., Wyession 1996), that cemetery is by no means ubiquitous at the CMB: subducted slabs are either unevenly interred, or efficiently excavated by later upwellings.
DS202008-1393
2020
Jackson, M.G.Giuliani, A., Jackson, M.G., Fitzpayne, A.The role of FOZO-PREMA in kimberlite genesis. Goldschmidt 2020, 1p. AbstractMantlekimberlite

Abstract: FOZO-PREMA is an ubiquitous component of oceanic basalts and was originally defined by the convergence of Sr- Nd-Pb isotope trends of ocean island basalts (OIBs) from individual island-seamount chains [1]. FOZO-PREMA is also widespread in juvenile continental magmas, which argue for a global relevance of this component irrespective of the tectonic settings. Early studies proposed that FOZO-PREMA could be a physically discrete reservoir derived from depletion of primitive mantle based on the combination of geochemically depleted 143Nd/144Nd combined with elevated 3He/4He ratios [2]. Conversely, later models showed that isotopic compositions spanning the FOZO-PREMA field can be obtained by mixing recycled oceanic crust and mantle material previously depleted by crust extraction [3]. Kimberlites can provide a new perspective on this debate because a recent study of the Nd and Hf isotope compositions of kimberlite through time shows that these magmas sample a deep, long-lived, homogeneous reservoir, which might contain remnants of early Earth differentiation processes [4]. We critically review the Sr, Nd and Hf isotope compositions of kimberlites that were emplaced from ~2.1 Ga. After screening kimberlite isotopic data for the effects of lithospheric contamination and secondary alteration, we show that kimberlites through time have been derived from a mantle source with FOZO-PREMA composition. This observation makes it unlikely that FOZO-PREMA derives from continuous mixing of depleted and recycled components because the composition of subducted lithologies, pressure and temperature conditions in subduction zones, and temperature and oxygen fugacity conditions of the convective mantle have changed throughout Earth history. We therefore conclude that FOZO-PREMA is a long-lived component of Earth’s mantle, which must have existed for at least the last 2.1 Ga, the wider implications of which will be discussed.
DS202102-0193
2020
Jackson, M.G.Giuliani, A., Jackson, M.G., Fitzpayne, A., Dalton, H.Remnants of early Earth differentiation in the deepest mantle-derived lavas. ( kimberlite source)PNAS, Vol. 118, 1 e201521118, 9p. PdfMantlekimberlite

Abstract: The noble gas isotope systematics of ocean island basalts suggest the existence of primordial mantle signatures in the deep mantle. Yet, the isotopic compositions of lithophile elements (Sr, Nd, Hf) in these lavas require derivation from a mantle source that is geochemically depleted by melt extraction rather than primitive. Here, this apparent contradiction is resolved by employing a compilation of the Sr, Nd, and Hf isotope composition of kimberlites—volcanic rocks that originate at great depth beneath continents. This compilation includes kimberlites as old as 2.06 billion years and shows that kimberlites do not derive from a primitive mantle source but sample the same geochemically depleted component (where geochemical depletion refers to ancient melt extraction) common to most oceanic island basalts, previously called PREMA (prevalent mantle) or FOZO (focal zone). Extrapolation of the Nd and Hf isotopic compositions of the kimberlite source to the age of Earth formation yields a 143Nd/144Nd-176Hf/177Hf composition within error of chondrite meteorites, which include the likely parent bodies of Earth. This supports a hypothesis where the source of kimberlites and ocean island basalts contains a long-lived component that formed by melt extraction from a domain with chondritic 143Nd/144Nd and 176Hf/177Hf shortly after Earth accretion. The geographic distribution of kimberlites containing the PREMA component suggests that these remnants of early Earth differentiation are located in large seismically anomalous regions corresponding to thermochemical piles above the core-mantle boundary. PREMA could have been stored in these structures for most of Earth’s history, partially shielded from convective homogenization.
DS202104-0578
2020
Jackson, M.G.Giuliani, A., Jackson, M.G., Fitzpayne, A., Dalton, H.Remnants of early Earth differentiation in the deepest mantle-derived lavas.Proceedings of the National Academy of Sciences PNAS, Vol. 118, 1 e201521118 9p. PdfMantlekimberlite

Abstract: The noble gas isotope systematics of ocean island basalts suggest the existence of primordial mantle signatures in the deep mantle. Yet, the isotopic compositions of lithophile elements (Sr, Nd, Hf) in these lavas require derivation from a mantle source that is geochemically depleted by melt extraction rather than primitive. Here, this apparent contradiction is resolved by employing a compilation of the Sr, Nd, and Hf isotope composition of kimberlites—volcanic rocks that originate at great depth beneath continents. This compilation includes kimberlites as old as 2.06 billion years and shows that kimberlites do not derive from a primitive mantle source but sample the same geochemically depleted component (where geochemical depletion refers to ancient melt extraction) common to most oceanic island basalts, previously called PREMA (prevalent mantle) or FOZO (focal zone). Extrapolation of the Nd and Hf isotopic compositions of the kimberlite source to the age of Earth formation yields a 143Nd/144Nd-176Hf/177Hf composition within error of chondrite meteorites, which include the likely parent bodies of Earth. This supports a hypothesis where the source of kimberlites and ocean island basalts contains a long-lived component that formed by melt extraction from a domain with chondritic 143Nd/144Nd and 176Hf/177Hf shortly after Earth accretion. The geographic distribution of kimberlites containing the PREMA component suggests that these remnants of early Earth differentiation are located in large seismically anomalous regions corresponding to thermochemical piles above the core-mantle boundary. PREMA could have been stored in these structures for most of Earth’s history, partially shielded from convective homogenization.
DS202202-0187
2022
Jackson, M.G.Bao, X., Lithgow-Bertelloni, C.R., Jackson, M.G., Romanowicz, B.On the relative temperatures of Earth's volcanic hotspots and mid-ocean ridges. ** not specific to diamondsScience, Vol. 375, 6576, pp. 57-61.Mantleplumes

Abstract: Volcanic hotspots are thought to be fed by hot, active upwellings from the deep mantle, with excess temperatures (Tex) ~100° to 300°C higher than those of mid-ocean ridges. However, Tex estimates are limited in geographical coverage and often inconsistent for individual hotspots. We infer the temperature of oceanic hotspots and ridges simultaneously by converting seismic velocity to temperature. We show that while ~45% of plume-fed hotspots are hot (Tex ? 155°C), ~15% are cold (Tex ? 36°C) and ~40% are not hot enough to actively upwell (50°C ? Tex ? 136°C). Hot hotspots have an extremely high helium-3/helium-4 ratio and buoyancy flux, but cold hotspots do not. The latter may originate at upper mantle depths. Alternatively, the deep plumes that feed them may be entrained and cooled by small-scale convection.
DS1970-0948
1974
Jackson, M.P.A.Kroner, A., Jackson, M.P.A.Geological Reconnaissance of the Coast between Luederitz And Marble Point Southwest Africa.Precambr. Res. Unit University Cape Town., Bulletin. No. 15, PP. 79-103.Southwest Africa, NamibiaGeology, Littoral Diamond Placers
DS1975-0298
1976
Jackson, M.P.A.Jackson, M.P.A.High Grade Metamorphism and Migmatization of the Namaqua Metamorphic Complex Around Aus in the Southern Namib Desert, South West Africa.Precamb. Res. Unit. University Cape Town., Bulletin. No. 18, 299P.Southwest Africa, NamibiaRegional Geology
DS1994-0815
1994
Jackson, M.P.A.Jackson, M.P.A., Vendeville, B.C.Regional extension as a geologic trigger for diapirisMGeological Society of America Bulletin, Vol. 106, No. 1, January pp. 57-73GlobalTectonics, Salt diapirs
DS200612-0629
2005
Jackson, M.P.A.Jackson, M.P.A., Hudec, M.R., Hegarty, K.A.The great West African Tertiary coastal uplift: fact or fiction? A perspective from the Angola Rift.Tectonics, Vol. 24, 6, TC6013. 10.1029/2005 TC1836Africa, West Africa, AngolaGeomorphology
DS1989-0076
1989
Jackson, P.D.Baria, R., Jackson, P.D., McCann, D.M.Further development of a high frequency seismic source for use inboreholesGeophysical Prospecting, Vol. 37, No. 1, January pp. 31-52GlobalGeophysics, Seismic - drillholes
DS1982-0293
1982
Jackson, P.L.Jackson, P.L.Appraisal of Land sat Lineaments As Faults in Western Kentucky. Final Report.National Technical Information Service DOE MC 16463-1324., 71P.GlobalMid-continent, Geophysics
DS1989-0655
1989
Jackson, R.D.Holm, R.G., Jackson, R.D., Yuan, B.Surface reflectance factor retrieval from thematic mapper dataRemote Sensing Environ, Vol. 27, pp. 47-57. Database # 17792GlobalRemote Sensing, TEM.
DS200912-0245
2009
Jackson, R.H.Gerlings, J., Funck, T., Jackson, R.H., Louden, K.E., Klingelhofer, F.Seismic evidence for plume derived volcanism during formation of the continental margin in southern Davis Strait and northern Labrador Sea.Geophysical Journal International, Vol. 176, 3, pp. 980-994.CanadaPlume
DS1970-0102
1970
Jackson, S.Jackson, S.The Great BarnatoLondon: Heinemann., 278P., ILLUS.South AfricaBiography, Kimberley
DS1998-0671
1998
Jackson, S.Jackson, S., Davies, R.Trace elements in the carbon of your choice by LAM ICP MSGemoc 1998 Annual Report, p. 28. abstractMantleDiamond inclusions
DS1998-1156
1998
Jackson, S.Petibon, C.M., Kjarsgaard, B., Jenner, G., Jackson, S.Liquidus phase relationships of a silicate bearing natro carbonatite from Oldoinyo Lengai at 20, 100 Mpa.Journal of Petrology, Vol. 39, No. 11-12, Nov-Dec. pp. 2137-51.TanzaniaCarbonatite, Deposit - Oldoinyo Lengai
DS2001-0517
2001
Jackson, S.Jackson, S., Davies, R., Griffin, B.Diamond fingerprints - for science and peaceGemoc Annual Report 2000, p. 23.GlobalMicroprobe analysis, Conflict diamonds
DS2003-1151
2003
Jackson, S.Rege, S., Davies, R.M., Griffin, W.L., Jackson, S., O'Reilly, S.Y.Trace element analysis of diamonds by LAM ICPMS: preliminary results8 Ikc Www.venuewest.com/8ikc/program.htm, Session 3, AbstractRussia, Siberia, Australia, Brazil, Northwest TerritoriesDiamonds - database 115, Geochemistry
DS200412-1648
2003
Jackson, S.Rege, S., Davies, R.M., Griffin, W.L., Jackson, S., O'Reilly, S.Y.Trace element analysis of diamonds by LAM ICPMS: preliminary results.8 IKC Program, Session 3, AbstractRussia, Siberia, AustraliaDiamonds - database 115 Geochemistry
DS201012-0476
2010
Jackson, S.Mather, K.A., Pearson, D.G., Kjarsgaard, B.A., Jackson, S.Understanding the lithosphere beneath Arctic Canada - an example from the N. Slave craton.38th. Geoscience Forum Northwest Territories, Abstract p. 65.Canada, Northwest TerritoriesDeposit - Artemisia
DS201012-0632
2010
Jackson, S.Robles-Cruz, S.E., Escayola, M., Melgarejo, J.C., Watangua, M., Gali, S., Goncalves, O.A., Jackson, S.Disclosed dat a from mantle xenoliths of Angolan kimberlites based on LA-ICP-MS analyses. Catoca and Cucumbi-79International Mineralogical Association meeting August Budapest, abstract p. 553.Africa, AngolaPetrology
DS201212-0318
2012
Jackson, S.Hunt, L.,Stachel, T., Pearson, D.G., Jackson, S., McLean, H., Kjarsgaard, B.The origin of websterites at Diavik diamondmine, Canada, and the realationship to diamond growth.10th. International Kimberlite Conference Feb. 6-11, Bangalore India, AbstractCanada, Northwest TerritoriesDeposit - Diavik
DS201212-0590
2012
Jackson, S.Robles-Cruz, S.E., Escayola, M., Jackson, S., Gali, S., Pervov, S., Watanga, M., Goncalves, A., Melgarejo, J.C.U-Pb SHRIMP geochronology of zircon from the Catoca kimberlite, Angola: implications for diamond exploration.Chemical Geology, Vol. 310-311, pp. 137-147.Africa, AngolaDeposit - Catoca
DS201810-2342
2018
Jackson, S.Lawley, C., Kjarsgaard, B., Jackson, S., Yang, Z., Petts, D., Roots, E.Trace metal and isotopic depth profiles through the Abitibi. Kirkland Lake kimberlite field.Lithos, Vol. 314-315, pp. 520-533.Canada, Ontariodeposit - Kirkland Lake

Abstract: Geophysical imaging of trans-lithospheric structures provide a spatial link between ore deposits in the crust and the underlying cratonic mantle. However, the deep lithosphere's role in ore deposit genesis remains poorly understood because remotely acquired datasets do not provide any direct constraints on the behaviour of ore elements within these mantle-roots. The abundance and behaviour of ore elements governs the metallic endowment of the cratonic mantle and the economic potential of mantle-derived magmas. Herein we present in situ electron probe microanalysis (EPMA) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) geochemical datasets for clinopyroxene and olivine mantle xenocrysts from the Jurassic Kirkland Lake kimberlite field, Abitibi greenstone belt, Canada. We specifically focus on unconventional trace elements, including ore elements with chalcophile and/or siderophile affinities (Ag-As-Au-Bi-Cu-Mo-Pb-Pt-Pd-Sb-Se-Sn-Te-W-Zn). Robust principal component analysis suggests that low-T, large-ion lithophile element alteration (Ba-Sr), which likely occurred during kimberlite emplacement, represents the largest source of variance for the xenocryst dataset. PT-dependent element partitioning during sub-solidus equilibration represents the second most important control on olivine and clinopyroxene chemistry. We demonstrate that least-altered, high-PT mantle silicates are, in fact, a significant mineral host for a range of ore elements (Cu-Zn ± Ag ± As ± Se ± Sn ± Mo) within equilibrated, garnet peridotite at depth (70-190 km). Statistical analysis of the raw, individual mass sweeps for each LA-ICP-MS signal suggest that the most abundant ore elements (Cu-Zn) occur predominantly as PT-dependent substitution reactions with the dominant mineral-forming elements, rather than as inclusions. A subset of high-PT olivine (160-180 km) yields Fe-Ni-S-poor and Na (Au ± Pt ± Pd)-rich compositions, which may reflect metasomatism, sulphide segregation and trapping of precious metal-bearing fluids at the base of the lithosphere. These anomalous mantle fragments possibly represent the first, direct sampling of precious metal-modified mantle peridotite beneath the Abitibi. Mid-PT olivine xenocrysts (70-120 km), which yield Mg-rich and high field-strength element-poor compositions, document a highly melt-depleted segment of mantle peridotite coincident with and below a shallow-dipping, low-seismic-velocity anomaly and conductive feature of the Kirkland Lake mid-lithosphere at 70-100 km. We speculate that the trace element signature of mid-PT xenocrysts documents the re-distribution of high-charge and incompatible elements from refractory garnet peridotite to phlogopite- and/or amphibole-bearing peridotite with conductive metasomatic up-flow zones. The rapid, sub-solidus diffusion of elements at high-T suggest that these processes likely occurred during, and/or immediately preceding, kimberlite volcanism. New in situ Pb isotope analyses of clinopyroxene xenocrysts sampled from metasomatized, low-Al garnet peridotite, however, also document ancient metasomatic events that likely pre-date Jurassic kimberlitic volcanism by at least one billion years.
DS1994-0816
1994
Jackson, S.A.Jackson, S.A.Diamond exploration in North America: status report January 1994Preprint of talk given at Dregs Meeting Feb. 1994., 1p text and 2 maps.United States, CanadaNews item
DS1992-0762
1992
Jackson, S.E.Jackson, S.E., et al.The application of laser-ablation microprobe - inductively coupled plasma-mass spectrometry (LAM-ICP-MS) to in situ trace element determinationsCanadian Mineralogist, Vol. 30, Pt. 4, December, pp. 1049-1064GlobalSpectrometry, Overview and examples in specific minerals
DS1992-0763
1992
Jackson, S.E.Jackson, S.E., et al.The application of laser-ablation microprobe -inductively coupled plasma-mass spectrometry (LAM-ICP-MS) to in situ trace element determinationsCanadian Mineralogist, Vol. 30, Pt. 4, December pp. 1049-1064GlobalSpectrometry, Overview -uses garnet not specific to diamond interests
DS1993-0924
1993
Jackson, S.E.Longerich, H.P., Jackson, S.E., Fryer, B.J., Strong, D.F.The laser ablation microprobe-inductively coupled plasma-massspectrometerGeoscience Canada, Vol. 20, No. 1, March pp. 21-25GlobalSpectrometry, Exploration techniques
DS1996-0460
1996
Jackson, S.E.Foley, S.F., Jackson, S.E., Jenner, G.A.Trace element partition coefficients for clinopyroxene and phlogopite in an alkaline lamprophyre from NewfoundlandGeochimica et Cosmochimica Acta, Vol. 60, No. 4, Feb. 1, pp. 629-638.NewfoundlandLamprophyre, Microscopy
DS1997-0904
1997
Jackson, S.E.Petibon, C.M., Jenner, G.A., Jackson, S.E., Kjarsgaard, B.Petrogenesis of Oldoinyo Lengai carbonatites: constraints from trace element partition coefficients.Geological Association of Canada (GAC) Abstracts, TanzaniaCarbonatite, Deposit - Oldoinyo Lengai
DS200412-0034
2004
Jackson, S.E.Andersen, T., Griffin, W.L., Jackson, S.E., Knudsen, T.L., Pearson, N.J.Mid-Proterozoic magmatic arc evolution at the southwest margin of the Baltic Shield.Lithos, Vol. 73, 3-4, April pp. 289-318.Europe, Norway, Baltic ShieldMagmatism, Laser ablation, geochronology
DS200612-0501
2006
Jackson, S.E.Griffin, W.L., Rege, S., O'Reilly, S.Y., Jackson, S.E., Pearson, N.J., Zedgenizov, D., Kurat, G.Trace element patterns of diamond: toward a unified genetic model.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 218. abstract only.TechnologyDiamond genesis geochemistry
DS200612-1528
2006
Jackson, S.E.Wieland, P.R., Beyer, E., Jackson, S.E., Pearson, N.J., O'Reilly, S.Y.Evaluation of a method of the separation of Ni in geological samples.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 19 abstract only.TechnologyGeochemistry - nickel
DS200812-0829
2008
Jackson, S.E.O'Reilly, S.Y., Griffin, W.L., Pearson, N.J., Jackson, S.E., Belousova, E.A., Alard, O., Saeed, A.Taking the pulse of the Earth: linking crustal and mantle events.Australian Journal of Earth Sciences, Vol. 55, pp. 983-995.MantleGeochronology
DS200812-0945
2008
Jackson, S.E.Rege, S., Griffin, W.L., Kurat, G., Jackson, S.E., Pearson, N.J., OReilly, S.Y.Trace element geochemistry of diamondite: crystallization of diamond from kimberlite carbonatite melts.Lithos, Vol. 106, 1-2, pp. 39-54.TechnologyDiamondite
DS201112-0862
2011
Jackson, S.E.Riches, A.J.V., Pearson, D.G., Kjarsgaard, B.A., Jackson, S.E., Stachel, T., Armstrong, J.P.Deep lithosphere beneath the Rae Craton: peridotite xenoliths from Repulse Bay, Nunavut.Yellowknife Geoscience Forum Abstracts for 2011, abstract p. 74-75.Canada, Nunavut, Victoria Island, Parry PeninsulaMineralogy
DS201212-0585
2012
Jackson, S.E.Riches, A.J.V., Pearson, D.G., Stern, R.A., Ickert, R.B., Kjarsgaard, B.A., Jackson, S.E., Ishikawa, A.Multi-stage metasomatism of a Roberts Victor eclogite linked to the formation and destruction of diamond.10th. International Kimberlite Conference Feb. 6-11, Bangalore India, AbstractAfrica, South AfricaDeposit - Roberts Victor
DS201412-0315
2014
Jackson, S.E.Griffin, W.L., Pearson, N.J., Andersen, T., Jackson, S.E., O'Reilly, S.Y., Zhang, M.Sources of cratonic metasomatic fluids: In-situ LA-MC-ICPMS analysis of Sr, Nd and Pb isotopes in Lima from the Jagersfontein kimberlite.American Journal of Science, Vol. 314, pp. 435-461.Africa, South AfricaDeposit - Jagersfontein
DS201511-1847
2015
Jackson, S.E.Julian, B.R., Foulger, G.R., Hatfield, O., Jackson, S.E., Simpson, E., Einbeck, J., Moore, A.Hotspots in hindsight. Mentions kimberlitesGeological Society of America Special Paper, No. 514, pp. SPE514-08.MantleHotspots

Abstract: Thorne et al. (2004), Torsvik et al. (2010; 2006) and Burke et al. (2008) have suggested that the locations of melting anomalies ("hot spots") and the original locations of large igneous provinces ("LIPs") and kimberlite pipes, lie preferentially above the margins of two "large lower-mantle shear velocity provinces", or LLSVPs, near the bottom of the mantle, and that the geographical correlations have high confidence levels (> 99.9999%) (Burke et al., 2008, Fig. 5). They conclude that the LLSVP margins are "Plume-Generation Zones", and that deep-mantle plumes cause hot spots, LIPs, and kimberlites. This conclusion raises questions about what physical processes could be responsible, because, for example, the LLSVPs are apparently dense and not abnormally hot (Trampert et al., 2004). The supposed LIP-hot spot-LLSVP correlations probably are examples of the "Hindsight Heresy" (Acton, 1959), of performing a statistical test using the same data sample that led to the initial formulation of a hypothesis. In this process, an analyst will consider and reject many competing hypotheses, but will not adjust statistical assessments correspondingly. Furthermore, an analyst will test extreme deviations of the data, , but not take this fact into account. "Hindsight heresy" errors are particularly problematical in Earth science, where it often is impossible to conduct controlled experiments. For random locations on the globe, the number of points within a specified distance of a given curve follows a cumulative binomial distribution. We use this fact to test the statistical significance of the observed hot spot-LLSVP correlation using several hot-spot catalogs and mantle models. The results indicate that the actual confidence levels of the correlations are two or three orders of magnitude smaller than claimed. The tests also show that hot spots correlate well with presumably shallowly rooted features such as spreading plate boundaries. Nevertheless, the correlations are significant at confidence levels in excess of 99%. But this is confidence that the null hypothesis of random coincidence is wrong. It is not confidence about what hypothesis is correct. The correlations probably are symptoms of as-yet-unidentified processes.
DS201601-0040
2015
Jackson, S.E.Riches, A.J.V., Ickert, R.B., Pearson, D.G., Stern, R.A., Jackson, S.E., Ishikawa, A.In situ oxygen isotope, major-, and trace element constraints on the metasomatic modification and crustal origin of a Diamondiferous eclogite from Roberts Victor, Kaapvaal Craton.Geochimica et Cosmochimica Acta, in press available, 45p.Africa, South AfricaDeposit - Roberts Victor
DS201603-0417
2016
Jackson, S.E.Riches, A.J.V., Ickert, R.B., Pearson, D.G., Stern, R.A., Jackson, S.E., Ishikawa, A., Kjarsgaard, B.A., Gurney, J.J.In situ oxygen-isotope, major, and trace element constraints on the metasomatic modification and crust origin of a Diamondiferous eclogite from Roberts Victor, Kaapvaal craton.Geochimica et Cosmochimica Acta, Vol. 174, pp. 345-359.Africa, South AfricaDeposit - Roberts Victor
DS201809-2054
2018
Jackson, S.E.Lawley, C.J.M., Kjarsgaard, B.A., Jackson, S.E., Yang, Z., Petts, D.C.Olivine and clinopyroxene mantle xenocryst geochemistry from the Kirkland Lake kimberlite field, Ontario.Geological Survey of Canada, Open File 8376, 9p.Canada, Ontariogeochemistry
DS201908-1773
2019
Jackson, S.E.Bussweiler, Y., Giuliani, A., Greig, A., Kjarsgaard, B.A., Petts, D., Jackson, S.E., Barrett, N., Luo, Y., Pearson, D.G.Trace element analysis of high-Mg olivine by LA-ICP-MS - characterization of natural olivine standards for matrix-matched calibration and application to mantle peridotites.Chemical Geology, Vol. 524, pp. 136-157.Mantleperidotite

Abstract: The trace element composition of olivine is becoming increasingly important in petrological studies due to the ubiquity of olivine in the Earth's upper mantle and in primitive magmatic rocks. The LA-ICP-MS method allows for the routine analysis of trace elements in olivine to sub-ppm levels, but a major drawback of this method is the lack of knowledge about possible downhole fractionation effects when non matrix-matched calibration is used. In this contribution, we show that matrix-matched (i.e., olivine-based) calibration is preferable for small laser spot sizes (<100??m) due to significant laser-induced inter-element fractionation between olivine and commonly used silicate glass calibration materials, e.g., NIST SRM 612, GSD-1G and BHVO-2G. As a result, we present two Mg-rich natural olivine standards (355OL and SC-GB) that have been characterized by independent methods (EPMA, solution ICP-MS), and by LA-ICP-MS in four different laboratories. These natural olivines have been used 1) as primary standards for the matrix-matched calibration of olivine samples for most elements of interest (e.g., Li, Na, Al, P, Ca, Sc, Ti, V, Cr, Mn, Co, Ni, Cu, Zn), and 2) as secondary standards to assess the accuracy of results. Comparison of olivine- and silicate glass-calibrated results for natural peridotitic olivine reveals that matrix-matched calibration is essential when using small laser spot sizes (<100??m) in order to mitigate downhole fractionation effects for certain elements, especially Na, P, Mn, Co, Ni and Zn. If matrix-matched calibration is not feasible, we recommend that spot sizes of ?100??m, laser fluence of ?4.0?J/cm2, and total laser shot counts of ?250 (e.g., 5?Hz repetition rate for 50?s) are used in order to minimize fractionation effects between olivine and silicate glass calibration materials. We demonstrate the applicability of matrix-matched calibration on olivine from a suite of different mantle peridotite xenoliths sampled by kimberlites and alkali basalts from on-craton and off-craton localities.
DS202002-0202
2020
Jackson, S.E.Lawley, C.J.M., Pearson, G., Waterton, P., Zagorevski, A., Bedard, J.H., Jackson, S.E., Petts, D.C., Kjarsgaard, B.A., Zhang, S., Wright, D.Element and isotopic signature of re-fertilized mantle peridotite as determined by nanopower and olivine LA-ICPMS analyses.Chemical Geology, DOI:101016/ j.chemgeo.2020.119464Mantleperidotite

Abstract: The lithospheric mantle should be depleted in base- and precious-metals as these elements are transferred to the crust during partial melting. However, some melt-depleted mantle peridotites are enriched in these ore-forming elements. This may reflect re-fertilization of the mantle lithosphere and/or sequestering of these elements by residual mantle phase(s). Both processes remain poorly understood because of the low abundances of incompatible elements in peridotite and the nugget-like distribution of digestion-resistant mantle phases that pose analytical challenges for conventional geochemical methods. Herein we report new major and trace element concentrations for a suite of mantle peridotite and pyroxenite samples from the Late Permian to Middle Triassic Nahlin ophiolite (Cache Creek terrane, British Columbia, Canada) using Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICPMS) analysis of nanoparticulate powders and olivine. Compatible to moderately incompatible element concentrations suggest that Nahlin ophiolite peridotites represent residues after ?20% melt extraction. Pyroxenite dykes and replacive dunite bands are folded and closely intercalated with residual harzburgite. These field relationships, coupled with the presence of intergranular base metal sulphide, clinopyroxene and Cr-spinel at the microscale, point to percolating melts that variably re-fertilized melt-depleted mantle peridotite. Radiogenic Pb (206Pb/204Pb?=?15.402-19.050; 207Pb/204Pb?=?15.127-15.633; 208Pb/204Pb?=?34.980-38.434; n?=?45) and Os (187Os/188Os 0.1143-0.5745; n?=?58) isotope compositions for a subset of melt-depleted peridotite samples further support metasomatic re-fertilization of these elements. Other ore-forming elements are also implicated in these metasomatic reactions because some melt-depleted peridotite samples are enriched relative to the primitive mantle, opposite to their expected behaviour during partial melting. New LA-ICPMS analysis of fresh olivine further demonstrates that a significant proportion of the highly incompatible element budget for the most melt-depleted rocks is either hosted by, and/or occurs as trapped inclusions within, the olivine-rich residues. Trapped phases from past melting and/or re-fertilization events are the preferred explanation for unradiogenic Pb isotope compositions and Paleozoic to Paleoproterozoic Re-depletion model ages, which predate the Nahlin ophiolite by over one billion years.
DS202205-0726
2022
Jackson, S.E.Veglio, C., Lawley, C.J.M., Kjarsgaard, B., Petts, D., Pearson, G., Jackson, S.E.Olivine xenocrysts reveal carbonated mid-lithosphere in the northern Slave craton.Lithos, 10.1016/j.lithos.2022.106633, 14p. PdfCanada, Northwest Territoriesolivine

Abstract: The cold, rigid, and melt-depleted mantle underlying Archean cratons plays an important role in the preservation of the overlying continental crust and is one of the main sources of diamonds. However, with the possible exception of rare earth elements (REE) and platinum group-elements (PGE), the concentrations and host mineral phases for many other critical trace elements within lithospheric mantle remain very poorly understood. Here we address that knowledge gap, presenting new electron microprobe and laser-ablation inductively-coupled-plasma mass-spectrometry results for a suite of mantle xenoliths (n = 12) and olivine xenocrysts (n = 376) from the Jericho, Muskox, and Voyageur kimberlites (northern Slave craton, Canada). Low-temperature (<1000 °C) harzburgite xenoliths and olivine xenocrysts suggest that the shallowest portions of the garnet-bearing mantle (?160 km) underlying the northern Slave craton is chemically depleted and becomes increasing re-fertilized from 160 to 200 km. High-temperature (>1000 °C) garnet and clinopyroxene crystals with Ti/Eu ratios > > 1000, and olivine xenocrysts suggest that interaction with ultramafic silicate melts is the most likely mechanism to re-fertilize melt-depleted peridotite with incompatible elements toward the base of the lithosphere (~200 km). In contrast, lower temperature garnet and clinopyroxene with Ti/Eu ratios <1000 are more likely related to metasomatism by carbonatitic melts and/or fluids. Carbonatitic metasomatism is also interpreted as the preferred explanation for the trend of Nb (4 ppm)- and Ta (185 ppb)-rich concentrations of olivine xenocrysts sampled from mid-lithosphere depths (~140 km). With the exception of a few elements that substitute into the olivine crystal structure during sub-solidus re-equilibration (e.g., Ca, Cr, Cu, Na, Sc, V, Zn), most other olivine-hosted trace elements do not systematically vary with depth. Instead, we interpret olivine-hosted trace element concentrations that are significantly above the analytical detection and/or quantification limits to reflect trapped fluid (e.g., As, Mo, Sb, Sn), base-metal sulphide (e.g., Ag, Au, Bi, Pd, Pt, Se, Te), and other mineral inclusions (e.g., U, Th) rather than enrichments of these elements due to substitution reactions or analytical artefacts. We interpret that these inclusions occur in olivine throughout the garnet stability field, but are relatively rare. As a result, these trapped carbonatitic, proto-kimberlite, and/or other ultramafic silicate melts do not represent a significant source for the suite of trace elements that become enriched to economic levels in the crust.
DS1994-0532
1994
Jackson, S.F.Foley, S.F., Jenner, G.A., Jackson, S.F., Fryer, B.J.Trace element partition coefficients phlogopite, clinopyroxene and matrixin alkaline lamprophyre.Mineralogical Magazine, Vol. 58A, pp. 280-281. AbstractNewfoundlandLamprophyre, Alkaline rocks -Notre Dame Bay
DS1990-0750
1990
Jackson, S.L.Jackson, S.L., Sutcliffe, R.H.Central Superior Province geology: evidence for an allochthonous, ensimatic, southern Abitibi greenstone beltCanadian Journal of Earth Sciences, Vol. 27, No. 4, April pp. 582-589OntarioTectonics -Superior, Abitibi greenstone belt
DS1991-0309
1991
Jackson, S.L.Corfu, F., Jackson, S.L., Sutcliffe, R.H.uranium-lead (U-Pb) (U-Pb) ages and tectonic significance of late Archean alkalic magmatism and nonmarine sedimentation: Timiskaming Group, southern Abitibi belt, OntarioCanadian Journal of Earth Sciences, Vol. 28, No. 4, April pp. 489-503OntarioTectonics, Geochronology
DS1994-0817
1994
Jackson, S.L.Jackson, S.L., Fyon, J.A., Corfu, F.Review of Archean supracrustal assemblages of the southern Abitibi Greenstone belt in Ontario, Canada: products of microplate interaction within alarge scale platePrecambrian Research, Vol. 65, No. 1-4, January pp. 183-206OntarioAbitibi greenstone belt, Tectonics
DS1992-0434
1992
Jackson, V.Epp, H., Jackson, V.Satellite remote sensing in the search for kimberlite pipes in the Northwest TerritoriesNorthwest Territories Geoscience Forum held November 25, 26th. 1992, poster, AbstractNorthwest TerritoriesGeophysics, Remote sensing
DS2003-0098
2003
Jackson, V.Bennett, V., Jackson, V., Rivers, T., Tubrett, M., Relf, C.Mapping lower crustal age domains utilizing LAM ICP MS U-Pb dating of inherited31st Yellowknife Geoscience Forum, p. 5. (abst.NunavutGeochronology, Tectonics, SRT
DS200412-0133
2003
Jackson, V.Bennett, V., Jackson, V., Rivers, T., Tubrett, M., Relf, C.Mapping lower crustal age domains utilizing LAM ICP MS U-Pb dating of inherited zircons: a new diamond exploration tool?31st Yellowknife Geoscience Forum, p. 5. (abst.Canada, NunavutGeochronology, Tectonics, SRT
DS201911-2551
2019
Jackson, V.Ootes, L., Sandemann, H., Cousens, B.L.,Luo, Y., Pearson, D.G., Jackson, V.Pyroxenite magma conduits ( ca 1.86 Ga) in Wopmay orogen and Slave craton: petrogenetic constrainst from whole rock and mineral chemistry.Lithos, in press available, 54p.Canada, Northwest Territorieslamprophyres
DS1994-0585
1994
Jackson, V.A.Gebert, J.S., Jackson, V.A.Preliminary compilation of the Point Lake Contwyoto Napultulik Kathawachaga Lakes area.Diand., EGS 1994-2, map.Northwest TerritoriesGeology
DS200612-0121
2006
Jackson, V.A.Bennett, V., Jackson, V.A., Rivers, T., Relf, C., Horan, P., Tubrett, M.Geology and U Pb geochronology of the Neoarchean Snare River terrane: tracking evolving tectonic regimes and crustal growth mechanisms.Canadian Journal of Earth Sciences, Vol. 42, 6, pp. 895-934.Canada, Northwest TerritoriesGeochronology
DS200912-0723
2009
Jackson, V.A.Spratt, J.E., Jones, A.G., Jackson, V.A., Collins, L., Avdeeva, A.Lithospheric geometry of the Wopmay orogen from a Slave Craton to Bear province magnetotelluric transect.Journal of Geophysical Research, Vol. 114, B1 B01101.CanadaGeophysics - magnetotellurics
DS201412-0636
2014
Jackson, V.A.Normandeau, P.X., Mcmartin, L., Jackson, V.A., Corriveau, L., Paquette, J.Kimberlite indicator minerals and gold grains in till from the Great Bear magmatic zone and Wopmay metamorphic zone, Northwest Territories, Canada.2014 Yellowknife Geoscience Forum Poster, p. 97, abstractCanada, Northwest TerritoriesKIMs in till
DS201707-1354
2017
Jackson, V.A.Ootes, L., Jackson, V.A., Davis, W.J., Bennett, V., Smar, L., Cousens, B.L.Parentage of Archean basement within a Paleoproterozoic orogen and implications for on-craton diamond preservation: Slave craton and Wopmay orogen, northwest Canada.Canadian Journal of Earth Sciences, Vol. 54, pp. 203-232.Canada, Northwest Territorieskimberlite

Abstract: The Wopmay orogen is a Paleoproterozoic accretionary belt preserved to the west of the Archean Slave craton, northwest Canada. Reworked Archean crystalline basement occurs in the orogen, and new bedrock mapping, U–Pb geochronology, and Sm–Nd isotopic data further substantiate a Slave craton parentage for this basement. Detrital zircon results from unconformably overlying Paleoproterozoic supracrustal rocks also support a Slave craton provenance. Rifting of the Slave margin began at ca. 2.02 Ga with a second rift phase constrained between ca. 1.92 and 1.89 Ga, resulting in thermal weakening of the Archean basement and allowing subsequent penetrative deformation during the Calderian orogeny (ca. 1.88–1.85 Ga). The boundary between the western Slave craton and the reworked Archean basement in the southern Wopmay orogen is interpreted as the rifted cratonic margin, which later acted as a rigid backstop during compressional deformation. Age-isotopic characteristics of plutonic phases track the extent and evolution of these processes that left penetratively deformed Archean basement, Paleoproterozoic cover, and plutons in the west, and “rigid” Archean Slave craton to the east. Diamond-bearing kimberlite occurs across the central and eastern parts of the Slave craton, but kimberlite (diamond bearing or not) has not been documented west of ?114°W. It is proposed that while the crust of the western Slave craton escaped thermal weakening, the mantle did not and was moved out of the diamond stability field. The Paleoproterozoic extension–convergence cycle preserved in the Wopmay orogen provides a reasonable explanation as to why the western Slave craton appears to be diamond sterile.
DS1994-0818
1994
Jackson, W.D.Jackson, W.D., Christiansen, G.International strategic minerals inventory summar report -rare earthoxidesUnited States Geological Survey (USGS) Circ, No. 930-N, 70pUnited States, GlobalEconomics, Rare earths
DS202108-1302
2021
Jacob, B.Pamato, M.G., Novella, D., Jacob, B., Oliveira, B., Pearson, D.G.Petrogenetic sulfide inclusions in diamonds date the diamond formation event using Re-Os isotopes.Geology, Vol. 49, pp. 941-945.Canada, Ontario, Nunavutdeposit - Victor, Jericho

Abstract: Sulfides are the most abundant inclusions in diamonds and a key tool for dating diamond formation via Re-Os isotopic analyses. The manner in which fluids invade the continental lithospheric mantle and the time scale at which they equilibrate with preexisting (protogenetic) sulfides are poorly understood yet essential factors to understanding diamond formation and the validity of isotopic ages. We investigated a suite of sulfide-bearing diamonds from two Canadian cratons to test the robustness of Re-Os in sulfide for dating diamond formation. Single crystal X-ray diffraction (XRD) allowed determination of the original monosulfide solid-solution (Mss) composition stable in the mantle, indicating subsolidus conditions of encapsulation, and providing crystallographic evidence supporting a protogenetic origin of the inclusions. The results, coupled with a diffusion model, indicate Re-Os isotope equilibration is sufficiently fast in sulfide inclusions with typical grain size, at mantle temperatures, for the system to be reset by the diamond-forming event. This confirms that even if protogenetic, the Re-Os isochrons defined by these minerals likely reflect the ages of diamond formation, and this result highlights the power of this system to date the timing of fluid migration in mantle lithosphere.
DS1991-0777
1991
Jacob, D.Jacob, D., Jagoutz, E., Sobolev, N.V.A diamond graphite bearing eclogitic xenolith from Roberts Victor-indication for petrogenesis from lead, neodymium, and Sr isotopesProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 190-192South AfricaGeochronology, Geochemistry
DS1993-0728
1993
Jacob, D.Jacob, D., Jagoutz, E., et al.Diamondiferous eclogites from Siberia: ancient oceanic crustAmerican Geophysical Union, EOS, supplement Abstract Volume, October, Vol. 74, No. 43, October 26, abstract p. 637.Russia, SiberiaEclogite
DS1994-0819
1994
Jacob, D.Jacob, D., Jagoutz, E.A diamond graphite bearing eclogitic xenoliths from Roberts Victor (SouthAfrica) -indication for petrogenesis from lead neodymium and Sr isotopes.Proceedings of Fifth International Kimberlite Conference, Vol. 1, pp. 304-317.South AfricaGeochronology, Deposit -Roberts Victor
DS1994-0820
1994
Jacob, D.Jacob, D., Jagoutz, E., Lowry, D., Mattey, D., KudrjavtsevaDiamondiferous eclogites from Siberia: remnants of Archean oceanic crustGeochimica et Cosmochimica Acta, Vol. 58, 23, pp. 5191-207.Russia, SiberiaEclogites, Deposit -Udachnaya
DS1998-0672
1998
Jacob, D.Jacob, D., Jagoutz, E., Zinngrebe, E., Snyder, TaylorComment and reply on the origins of Yakutian eclogite xenolithsJournal of Petrology, Vol. 39, No. 8, Aug. 1, pp. 1527-1539.Russia, YakutiaEclogites, Diamond genesis
DS1998-1648
1998
Jacob, D.Zinngrebe, E., Jacob, D., Ramos, Z., Smith, C.B.A model for eclogite peridotite interactions: activity driven with evidence from Zero eclogiteMineralogical Magazine, Goldschmidt abstract, Vol. 62A, p. 1705-6.South AfricaSubduction, eclogite, Deposit - Zero
DS200412-0563
2004
Jacob, D.Foley, S., Vannucci, R., Jacob, D., Tiepolo, M.The geochemical signature and origin of Archean TTG gneisses: melting of amphibolite or eclogite?Lithos, ABSTRACTS only, Vol. 73, p. S38. abstractTechnologySubduction
DS200612-0630
2006
Jacob, D.Jacob, D., Resiberg, L., Yaxley, G.Processes of mantle refertilization and modification.Goldschmidt Conference 16th. Annual, S5-05 theme abstract 1/8p. goldschmidt2006.orgMantleCraton
DS201112-0433
2011
Jacob, D.Hettmann, K., Marks, M., Kressing, K., Zack, T., Wenzel, T., Rehkamper, M., Jacob, D., Markl, G.The geochemistry of thallium and its isotopes in a peralkaline magmatic system.Peralk-Carb 2011, workshop held Tubingen Germany June 16-18, PosterTechnologyMagmatism
DS201505-0246
2015
Jacob, D.Griffin, W.L., Gain, S.E.M., Toledo, V., O'Reilly, S.Y., Jacob, D., Pearson, N.J.Corundum, moissanite and super reducing conditions in the upper mantle beneath the lower ( southern) Galilee ( Israel).Israel Geological Society, 1p.posterEurope, IsraelMineralogy
DS201605-0848
2016
Jacob, D.Jacob, D.Insights into subcratonic lithosphere development from banded eclogite xenoliths.DCO Edmonton Diamond Workshop, June 8-10MantleXenoliths
DS201902-0257
2019
Jacob, D.Aulbach, S., Heaman, L.M., Jacob, D., Viljoen, K.S.Ages and sources of mantle eclogites: ID-TIMS and in situ MC-ICPMS Pb-Sr isotope systematics of clinopyroxene.Chemical Geology, Vol. 503, pp. 15-28.Africa, South Africa, Zimbabwe, Sierra Leonedeposit - Lace, Orapa, Koidu

Abstract: Strontium and Pb isotopic compositions of clinopyroxene (cpx) in selected samples from three well-characterised eclogite suites with oceanic crustal protoliths (Lace/Kaapvaal craton, Orapa/Zimbabwe craton and Koidu/West African craton) were acquired by high-precision isotope dilution thermal ionisation mass spectrometry (ID-TIMS) and in situ multicollector-laser ablation-inductively-coupled plasma mass spectrometry (MC-LA-ICPMS). The aims of this study are twofold: (1) assess their utility to obtain formation or resetting age constraints and identify elemental signatures that enhance the chances of successful age dating, and (2) to confirm the veracity and utility of results obtained by novel MC-LA-ICPMS techniques. Strontium-Pb isotope systematics of eclogitic cpx measured in this study are decoupled and may reflect addition of unsupported radiogenic Sr during seawater alteration or interaction with oceanic sediments in subduction mélanges, and/or disturbance due to mantle metasomatism, to which the more incompatible Pb is more susceptible. Despite a complex history, subsets of samples yield meaningful model dates. Clinopyroxene fractions from Lace with high Pb contents (3-6?ppm), unradiogenic Pb isotopic compositions (206Pb/204Pb?=?13.57-13.52) and low 238U/204Pb (1.0-1.5) give single-stage model Pb dates of 2.90-2.84?Ga. In contrast, samples from Orapa plot to the right of the Geochron and do not yield meaningful Pb model ages. However, these data do define secondary isochrons that can be modelled to yield minimum age constraints on major events affecting the cratonic lithosphere. Within the uncertainties, the resultant 2.18?±?0.45?Ga age obtained for Koidu eclogites reflect disturbance of the Pb isotope system due to subduction beneath the craton linked to the Eburnean orogeny, while they retained their unradiogenic 87Sr/86Sr (0.7016). Similarly, the age for samples from Orapa (2.20?±?0.54?Ga) is interpreted as an overprint age related to Palaeoproterozoic accretion at the western craton margin. Gabbroic eclogites (Eu/Eu*?>?1) with plagioclase-rich protoliths having low time-integrated Rb/Sr and U/Pb retain the least radiogenic Sr and, in part, Pb. High model ? (9.0 to 9.1) for several eclogites from Lace with elevated LREE, Th and Pb abundances reflects ca. 3.0?Ga addition of a sedimentary component, possibly derived from reworking of a high-? basaltic protocrust, as observed on other cratons. We suggest that sample targeting can be usefully guided by fast-throughput in situ LA-ICPMS techniques, which largely yield results identical to ID-TIMS, albeit at lower precision, and which can further help identify kimberlite contamination in the mineral separates used for solution work.
DS1992-0764
1992
Jacob, D.E.Jacob, D.E., Jagutz, E.Diamondiferous eclogites and mixing of mantle componentsEos Transactions, Vol. 73, No. 14, April 7, supplement abstracts p. 324South AfricaGeochronology, Roberts Victor
DS1993-0729
1993
Jacob, D.E.Jacob, D.E., Jagoutz, E., Sobolev, N.V.Isotopic systematics of subcalcic garnets from SiberiaEos, Transactions, American Geophysical Union, Vol. 74, No. 16, April 20, supplement abstract p. 320Russia, SiberiaGeochemistry -garnets, Geochronology
DS1994-0821
1994
Jacob, D.E.Jacob, D.E., Jagoutz, E., Lowry, D., et al.Diamondiferous eclogites from Udachnaya: a subducted component in the Siberian upper mantle.Mineralogical Magazine, Vol. 58A, pp. 448-449. AbstractRussia, SiberiaEclogites, diamond genesis, Deposit -Udachnaya
DS1995-0862
1995
Jacob, D.E.Jacob, D.E., Jagoutz, E., Sobolev, N.V., Sorowka, A.Isotopic analysis ( Samarium/neodymium, Rubidium-Strontium and Uranium/lead) of single subcalcic garnet grains from Yakutian kimberlites.Proceedings of the Sixth International Kimberlite Conference Abstracts, pp. 257-259.Russia, YakutiaGeochemistry, isotopes, Geochronology -garnets
DS1998-0673
1998
Jacob, D.E.Jacob, D.E., Foley, S.F.Evidence for Archean ocean crust with Island Arc signature from diamondiferous eclogite xenoliths.7th International Kimberlite Conference Abstract, pp. 358-60.South Africa, Russia, YakutiaXenoliths, Deposit - Udachnaya, Finsch, Jagersfontein, Kaalvallei
DS1998-0674
1998
Jacob, D.E.Jacob, D.E., Jagoutz, E., Sobolev, N.V.Neodynium and strontium isotopic measurements on single subcalcic garnet grains from Yakutian kimberlites.Neues Jahrbuch f?r Mineralogie Abh., No. 172, pp. 357-379.Russia, YakutiaGeochronology
DS1998-0675
1998
Jacob, D.E.Jacob, D.E., Kjarsgaard, B., Horn, I.Trace element concentrations by laser ablation ICP-MS in subcalcic garnets from Saskatchewan and Somerset Is.7th International Kimberlite Conference Abstract, pp. 361-63.Saskatchewan, Somerset IslandGeochemistry, Deposit - Fort a la Corne
DS1998-0676
1998
Jacob, D.E.Jacob, D.E., Mattey, D.P.Geochemistry of layered kyanite bearing eclogites froim the Roberts Victormine.7th International Kimberlite Conference Abstract, pp. 364-5.South AfricaGeochemistry - garnets, Deposit - Roberts Victor
DS1999-0328
1999
Jacob, D.E.Jacob, D.E., Foley, S.F.Evidence for Archean ocean crust with low high field strength element signature - Diamondiferous eclogiticLithos, Vol. 48, No. 1-4, Sept. pp. 317-GlobalEclogites, xenoliths, Mineral chemistry
DS2001-0518
2001
Jacob, D.E.Jacob, D.E.Evidence for the geochemistry and petrology of Late Archean oceanic crust from mantle eclogite xenoliths.Geological Association of Canada (GAC) Annual Meeting Abstracts, Vol. 26, p.70, abstract.GlobalEclogites
DS2003-0415
2003
Jacob, D.E.Foley, S.F., Buhre, S., Jacob, D.E.Evolution of the Archean crust by delamination and shallow subductionNature, No. 6920, Jan 16, pp. 249-51.MantleSubduction
DS2003-0416
2003
Jacob, D.E.Foley, S.F., Buhre, S., Jacob, D.E., Rehfeldt, T.Pyroxenite and dunite xenoliths as metamorphosed cumulates from the Archean lower8ikc, Www.venuewest.com/8ikc/program.htm, Session 2, POSTER abstractGlobalEclogites and Diamonds
DS2003-0630
2003
Jacob, D.E.Jacob, D.E.The origin of eclogite xenoliths from the Earth's mantle8 Ikc Www.venuewest.com/8ikc/program.htm, Session 2, AbstractGlobalEclogites, diamonds - petrogenetic, Review
DS2003-0631
2003
Jacob, D.E.Jacob, D.E., Fung, A., Jagoutz, E., Pearson, D.G.Petrology and geochemistry of eclogite xenoliths from the Ekati kimberlite area8ikc, Www.venuewest.com/8ikc/program.htm, Session 2, POSTER abstractNorthwest TerritoriesEclogites and Diamonds, Deposit - Ekati
DS2003-0632
2003
Jacob, D.E.Jacob, D.E., Schmickler, B., Schulze, D.J.Trace element geochemistry of coesite bearing eclogites from the Roberts VictorLithos, Vol. 71, 2-4, pp. 337-351.South AfricaGeochemistry - deposit
DS2003-1020
2003
Jacob, D.E.Nowell, G.M., Pearson, D.G., Jacob, D.E., Spetsius, S., Nixon, P.H., HaggertyThe origin of alkremites and related rocks: a Lu Hf Rb Sr and Sm Nd isotope study8ikc, Www.venuewest.com/8ikc/program.htm, Session 4, POSTER abstractRussia, YakutiaMantle geochemistry, Deposit - Udachnaya
DS200412-0888
2003
Jacob, D.E.Jacob, D.E.The origin of eclogite xenoliths from the Earth's mantle.8 IKC Program, Session 2, AbstractTechnologyEclogite, diamonds - petrogenetic Review
DS200412-0889
2004
Jacob, D.E.Jacob, D.E.Nature and origin of eclogite xenoliths from kimberlites.Lithos, Vol. 77, 1-4, Sept. pp. 295-316.Africa, South Africa, Sierra LeoneKuruman, Koidu, mineral chemistry, isotopes, mantle
DS200412-0890
2004
Jacob, D.E.Jacob, D.E., Kronz, A., Viljoen, K.S.Cohenite, native iron and troilite inclusions in garnets from polycrystalline diamond aggregates.Contributions to Mineralogy and Petrology, Vol. 146, 5, pp. 566-76.Africa, South AfricaDiamond inclusions
DS200412-0891
2003
Jacob, D.E.Jacob, D.E., Schmickler, B., Schulze, D.J.Trace element geochemistry of coesite bearing eclogites from the Roberts Victor kimberlite, Kaapvaal Craton.Lithos, Vol. 71, 2-4, pp. 337-351.Africa, South AfricaGeochemistry - deposit
DS200412-1754
2004
Jacob, D.E.Schmickler, B., Jacob, D.E., Foley, S.F.Eclogite xenoliths from the Kuruman kimberlites, South Africa: geochemical fingerprinting of deep subduction and cumulate procesLithos, Vol. 75, 1-2, July pp. 173-207.Africa, South AfricaSubduction, Zero, petrogenetic processes
DS200512-0471
2005
Jacob, D.E.Jacob, D.E., Bizimis, M., Salters, V.J.M.Lu Hf and geochemical systematics of recycled ancient oceanic crust: evidence from Roberts Victor eclogites.Contributions to Mineralogy and Petrology, Vol. 148, 6, pp. 707-720.Africa, South AfricaGeochemistry
DS200612-0403
2006
Jacob, D.E.Foley, S.F., Andronikov, A.V., Jacob, D.E., Melzer, S.Evidence from Antarctic mantle peridotite xenoliths for changes in mineralogy, geochemistry and geothermal gradients beneath a developing rift.Geochimica et Cosmochimica Acta, Vol. 70, 12, June pp. 3096-3120.AntarcticaGeothermometry
DS200612-0631
2006
Jacob, D.E.Jacob, D.E., Foley, S.F., Andonikov, A.V.Re-enrichment of cratonic lithospheric mantle beneath an evolving rift: mantle xenoliths from East Antarctica.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 285. abstract only.AntarcticaXenolith - geochemistry
DS200712-0883
2006
Jacob, D.E.Rehfeldt, T., Foley, S.F., Jacob, D.E.Restoration of premetasomatic protolith compositions in mantle xenoliths.Geochimica et Cosmochimica Acta, In press availableMantleMetasomatism
DS200712-0884
2007
Jacob, D.E.Rehfeldt, T., Foley, S.F., Jacob, D.E., Carlson, R.W.Characterizing Fe rich dunite xenoliths as cumulates of Phanerozoic and Archean flood basalt magmatism.Plates, Plumes, and Paradigms, 1p. abstract p. A827.Africa, South AfricaKimberley Cluster
DS200712-0885
2007
Jacob, D.E.Rehfeldt, T., Jacob, D.E., Carlson, R.W., Foley, S.F.Fe rich dunite xenoliths from South African kimberlites: cumulates from Karoo flood basalts.Journal of Petrology, Vol. 48, 7, pp. 1387-1409.Africa, South AfricaMineral chemistry
DS200812-0362
2008
Jacob, D.E.Foley, S.F., Jacob, D.E.Trace element and isotopic effects of mantle metasomatism by carbonatitic and alkaline silicate melts in the lower cratonic mantle lithosphere.9IKC.com, 3p. extended abstractMantleMelting
DS200812-0363
2008
Jacob, D.E.Foley, S.F., Yaxley, G.M., Rosenthal, A., Rapp, R.P., Jacob, D.E.Experimental melting of peridotites in the presence of CO2 and H2O at 40 - 60 kbar.9IKC.com, 3p. extended abstractTechnologyPeridotite - melting
DS200812-0948
2008
Jacob, D.E.Rehfeldt, T., Foley, S.F., Jacob, D.E., Carlson, R.W., Lowry, D.Contrasting types of metasomatism in dunite, wehrlite and websterite xenoliths from Kimberley, South Africa.Geochimica et Cosmochimica Acta, Vol. 73, 23, Dec. 1. pp. 5722-5756.Africa, South AfricaDeposit - Kimberley
DS200812-0949
2007
Jacob, D.E.Rehfeldt, T., Jacob, D.E., Carlson, R.W., Foley, S.F.Fe rich dunite xenoliths from South African kimberlites: cumulates from Karoo flood basalts.Journal of Petrology, Vol. 48, pp. 1387-1409.Africa, South AfricaXenoliths
DS200912-0081
2009
Jacob, D.E.Buhre, S., Jacob, D.E., Foley, S.F.Delayed continental crust formation on a hot Archean Earth.Goldschmidt Conference 2009, p. A171 Abstract.MantleMelting
DS200912-0608
2008
Jacob, D.E.Rahfeldt, T., Foley, S.F., Jacob, D.E., Carlson, R.W., Lowry, D.Contrasting types of metasomatism in dunite, wherlite and websterite xenoliths from Kimberley, South Africa.Geochimica et Cosmochimica Acta, Vol. 72, 5722-36.Africa, South AfricaDeposit - Kimberley
DS201012-0204
2010
Jacob, D.E.Foley, S.F., Jacob, D.E., O'Neill, H.St.C.Trace element variations in olivine phenocrysts from Ugand an potassic rocks as clues to the chemical characteristics of parental magmas.Contributions to Mineralogy and Petrology, In press available, 20p.Africa, UgandaGeochemistry - East African Rift
DS201012-0205
2009
Jacob, D.E.Foley, S.F., Yaxley, G.M., Rosenthal, A., Buhre, S., Kisseeva, E.S., Rapp, R.P., Jacob, D.E.The composition of near solidus melts of peridotite in the presence of CO2 and H2O between 40 and 60 kbar.Lithos, Vol. 112 S pp. 274-283.MantleMineral chemistry
DS201012-0243
2010
Jacob, D.E.Gonzaga, R.G., Lowry, D., Jacob, D.E., Le Roex, A., Schulze, D., Menzies, M.A.Eclogites and garnet pyroxenes: similarities and differences.Journal of Volcanology and Geothermal Research, Vol. 190, 1-2 pp. 235-247.TechnologyEclogite
DS201012-0244
2010
Jacob, D.E.Gonzaga, R.G., Menzies, M.A., Thirwala, M.F., Jacob, D.E., Le Roex, A.Eclogites and garnet pyroxenites: problems resolving provenance using Lu-Hf, Sm-Nd and Rb-Sr isotope systems.Journal of Petrology, Vol. 51, 1-2, pp. 513-535.MantleGeochronology
DS201012-0317
2010
Jacob, D.E.Jacob, D.E., Wirth, R., Enzmann, F., Kronz, A.Combined FIB/TEM and microcomputer tomography of polycrystalline diamond ( framesite) from Orapa, Botswana.International Mineralogical Association meeting August Budapest, abstract p. 178.Africa, BotswanaFramesite
DS201012-0621
2010
Jacob, D.E.Rehfeldt, T., Foley, S.F., Jacob, D.E., Pearson, D.G.Trace elements in mantle olivine and orthopyroxene from the North Atlantic and Kaapvaal Cratons.Goldschmidt 2010 abstracts, abstractAfrica, South Africa, EuropeGeochemistry
DS201112-0326
2011
Jacob, D.E.Foley, S.F., Jacob, D.E., O'Neill, H.St.C.Trace element variations in olivine phenocrysts from Ugand an potassic rocks as clues to the chemical characteristics of parental magma.Contributions to Mineralogy and Petrology, Vol, 167, 1, July pp. 1-20.Africa, UgandaAlkaline rocks, magmatism
DS201112-0470
2011
Jacob, D.E.Jacob, D.E., Wirth, R., Enzmann, F.Polycrystalline diamonds witness redox processes in the Earth's mantle.Goldschmidt Conference 2011, abstract p.1095.Africa, BotswanaDeposit - Orapa
DS201112-0471
2011
Jacob, D.E.Jacob, D.E., Wirth, R., Enzmann, F., Kronz, A., Schreiber, A.Nano-inclusion suite and high resolution micro-computed tomography of polycrystalline diamond (framesite) from Orapa, Botswana.Earth and Planetary Science Letters, Vol. 308, 3-4, pp. 307-316.Africa, BotswanaInclusions
DS201112-0472
2011
Jacob, D.E.Jacob, D.E., Wirth, R., Enzmann, F., Kronz, A., Schrieber, A.Nano-inclusion suite and high resolution micro-computed-tomography of polycrystalline diamond (framesite) from Orapa, Botswana.Earth and Planetary Science Letters, Vol. 308, 3-4, pp. 307-316.Africa, BotswanaDeposit - Orapa
DS201112-0924
2011
Jacob, D.E.Schilling, J., Marks, m.A.W., Wenzel, T., Vennenmann, T., Horvth, L., Tarassof, P., Jacob, D.E., Markl, G.The magmatic to hydrothermal evolution of the intrusive Mont Sainte Hilaire Complex: insights into the late stage evolution of peralkaline rocks.Journal of Petrology, Vol. 52, 11. pp. 2147-2185.Canada, QuebecAlkaline rocks, carbonatite
DS201312-0017
2013
Jacob, D.E.Ammannati, E., Foley, S.F., Avanzinelli, R., Jacob, D.E., Conticelli, S.Trace elements in olivine characterize the mantle source of subduction related potassic magmas.Goldschmidt 2013, AbstractMantleSubduction
DS201312-0271
2013
Jacob, D.E.Foley, S.F., Prelevic, D., Rehfeldt, T., Jacob, D.E.Minor and trace elements in olivines as probes into early igneous and mantle melting.Earth and Planetary Science Letters, Vol. 363, pp. 181-191.MantleMetasomatism
DS201312-0280
2013
Jacob, D.E.Fritschle, T., Prelevic, D., Foley, S.F., Jacob, D.E.Petrological characterization of the mantle source of Mediterranean lamproites: indications from major and trace elements of phlogopite.Chemical Geology, Vol. 353, pp. 267-279.Europe, SpainLamproite
DS201412-0086
2014
Jacob, D.E.Bussweiler, Y., Foley, S.F., Prelevic, D., Jacob, D.E., Pearson, D.G., Stachel, T.Olivine as a petrogenetic and exploration indicator in Lac de Gras kimberlites.2014 Yellowknife Geoscience Forum, p. 20, 21 abstractCanada, Northwest TerritoriesDeposit - Ekati
DS201412-0415
2014
Jacob, D.E.Jacob, D.E., Dobrrzhinetskaya, L., Wirth, R.New insight into polycrystalline diamond genesis from modern nanoanalytical techniques. Earth Science Reviews, Vol. 136, Sept. pp. 21-35.MantleDiamond, carbonado, UHP, subduction
DS201412-0870
2013
Jacob, D.E.Sommer, H., Wan,Y., Kroner, A., Xie, H., Jacob, D.E.Shrimp zircon ages and petrology of lower crustal granulite xenoliths from the Letseng-La-Terae kimberlite, Lesotho: further evidence for a Namaquanatal connection.South Africa Journal of Geology, Vol. 116, 2, pp. 183-198.Africa, LesothoDeposit - Letseng
DS201504-0187
2015
Jacob, D.E.Bussweiler, Y., Foley, S.F., Prelevic, D., Jacob, D.E.The olivine macrocryst problem: new insights from minor and trace element compositions of olivine from Lac de Gras kimberlites, Canada.Lithos, Vol. 220-223, pp. 238-252.Canada, Northwest TerritoriesDeposit - Ekati field

Abstract: This study presents detailed petrographical and geochemical investigations on remarkably fresh olivines in kimberlites from the EKATI Diamond Mine- located in the Tertiary/Cretaceous Lac de Gras kimberlite field within the Slave craton of Canada. Olivine, constituting about 42 vol.% of the analyzed samples, can be divided into two textural groups: (i) macrocrystic olivines, > 100 ?m sub-rounded crystals and (ii) groundmass olivines, < 100 ?m subhedral crystals. Olivines from both populations define two distinct chemical trends; a “ "mantle trend" with angular cores, showing low Ca (< 0.1 wt.% CaO) and high Ni (0.3-0.4 wt.% NiO) at varying Mg# (0.86-0.93), contrasts with a "melt trend" typified by thin (< 100 ?m) rims with increasing Ca (up to 1.0 wt.% CaO) and decreasing Ni (down to 0.1 wt.% NiO) contents at constant Mg# (~ 0.915). These findings are in agreement with recent studies suggesting that virtually all olivine is composed of xenocrystic (i.e. mantle-related) cores with phenocrystic (i.e. melt-related) overgrowths, thereby challenging the traditional view that the origin of kimberlitic olivine can be distinguished based on size and morphology. The two main trends can be further resolved into sub-groups refining the crystallization history of olivine; the mantle trend indicates a multi-source origin that samples the layered lithosphere below the Slave craton, whereas the melt trend represents multi-stage crystallization comprising a differentiation trend starting at mantle conditions and a second trend controlled by the crystallization of additional phases (e.g. chromite) and changing magma conditions (e.g. oxidation). These trends are also seen in the concentrations of trace elements not routinely measured in olivine (e.g. Na, P, Ti, Co, Sc, Zr). Trace element mapping with LA-ICP-MS reveals the distribution of these elements within olivine grains. The trace element distribution between the two trends appears to be consistent with phenocrystic olivine overgrowths mainly originating from dissolved orthopyroxene, showing enrichment in Zr, Ga, Nb, Sc, V, P, Al, Ti, Cr, Ca and Mn in the melt trend. In a sample of magmatic kimberlite from the Leslie pipe, the amount of xenocrystic and phenocrystic olivine is estimated to be around 23 vol.% and 19 vol.%, respectively. Subtraction of this xenocrystic olivine from the Leslie bulk composition, aimed at estimating the parental kimberlite melt, results in a minor decrease of Mg# (by about 0.01) and SiO2 content (by about 3 wt.%), whereas CaO increases (by about 3 wt.%).
DS201508-0350
2015
Jacob, D.E.Dongre, A.N., Jacob, D.E., Stern, R.A.Subduction related origin of eclogite xenoliths from the Wajrakarur kimberlite field, Eastern Dharwar craton, southern India: constraints from petrology and geochemistry.Geochimica et Cosmochimica Acta, Vol. 166, pp. 165-188.IndiaDeposit - Wajrakarur
DS201606-1093
2015
Jacob, D.E.Howell, D., Griffin, W.L., Yang, J., Gain, S., Stern, R.A., Huang, J-X., Jacob, D.E., Xu, X., Stokes, A.J., O'Reilly, S.Y., Pearson, N.J.Diamonds in ophiolites: contamination or a new diamond growth environment?Earth and Planetary Science Letters, Vol. 430, pp. 284-295.Asia, TibetLuobusa Massif Type Iib

Abstract: For more than 20 years, the reported occurrence of diamonds in the chromites and peridotites of the Luobusa massif in Tibet (a complex described as an ophiolite) has been widely ignored by the diamond research community. This skepticism has persisted because the diamonds are similar in many respects to high-pressure high-temperature (HPHT) synthetic/industrial diamonds (grown from metal solvents), and the finding previously has not been independently replicated. We present a detailed examination of the Luobusa diamonds (recovered from both peridotites and chromitites), including morphology, size, color, impurity characteristics (by infrared spectroscopy), internal growth structures, trace-element patterns, and C and N isotopes. A detailed comparison with synthetic industrial diamonds shows many similarities. Cubo-octahedral morphology, yellow color due to unaggregated nitrogen (C centres only, Type Ib), metal-alloy inclusions and highly negative View the MathML source?C13 values are present in both sets of diamonds. The Tibetan diamonds (n=3n=3) show an exceptionally large range in View the MathML source?N15 (?5.6 to +28.7‰+28.7‰) within individual crystals, and inconsistent fractionation between {111} and {100} growth sectors. This in contrast to large synthetic HPHT diamonds grown by the temperature gradient method, which have with View the MathML source?N15=0‰ in {111} sectors and +30‰+30‰ in {100} sectors, as reported in the literature. This comparison is limited by the small sample set combined with the fact the diamonds probably grew by different processes. However, the Tibetan diamonds do have generally higher concentrations and different ratios of trace elements; most inclusions are a NiMnCo alloy, but there are also some small REE-rich phases never seen in HPHT synthetics. These characteristics indicate that the Tibetan diamonds grew in contact with a C-saturated Ni-Mn-Co-rich melt in a highly reduced environment. The stable isotopes indicate a major subduction-related contribution to the chemical environment. The unaggregated nitrogen, combined with the lack of evidence for resorption or plastic deformation, suggests a short (geologically speaking) residence in the mantle. Previously published models to explain the occurrence of the diamonds, and other phases indicative of highly reduced conditions and very high pressures, have failed to take into account the characteristics of the diamonds and the implications for their formation. For these diamonds to be seriously considered as the result of a natural growth environment requires a new understanding of mantle conditions that could produce them.
DS201606-1102
2016
Jacob, D.E.Kvassnytsya, V., Wirth, R., Piazolo, S., Jacob, D.E., Trimby, P.Surface morphology and structural types of natural impact apographitic diamonds. IN RUSSIANSverkhtverdie Materiali ( Ukraine) in RUSSIAN, No. 2, pp. 3-17.TechnologyMorphology of lonsdaleite, diamond

Abstract: External and internal morphologies of natural impact apographitic diamonds (paramorphoses) have been studied. The (0001) surface morphology of the paramorphoses reflects their phase composition and the structural relationship of its constituting phases. Growth and etch figures together with the elements of crystal symmetry of lonsdaleite and diamond are developed on these surfaces. The crystal size of lonsdaleite is up to 100 nm, and that of diamond is up to 300 nm. Two types of structural relations between graphite, lonsdaleite, and diamond in the paramorphoses are observed: the first type (black, black-gray, colorless and yellowish paramorphoses): the (0001) graphite face is parallel to the (100) lonsdaleite face and parallel to (111) diamond; the second type (milky-white paramorphoses): the (0001) graphite is parallel to the (100) lonsdaleite and parallel to the (112) diamond. The first type of the paramorphoses contains lonsdaleite, diamond, graphite or diamond, lonsdaleite, the second type of the paramorphoses contains predominantly diamond. The direct phase transition of graphite ? lonsdaleite and/or graphite ?diamond occurred in the paramorphoses of the first type. A successive phase transition graphite ? lonsdaleite ? diamond was observed in the paramorphoses of the second type. The structure of the paramorphoses of this type shows characteristic features of recrystallization.
DS201607-1303
2016
Jacob, D.E.Jacob, D.E., Piazolo, S., Screiber, A., Trimby, P.Redox-freezing and nucleation of diamond via magnetite formation in the Earth's mantle.Nature Communications, Vol. 7, June 21, 7p.Africa, BotswanaDeposit - Orapa

Abstract: Diamonds and their inclusions are unique probes into the deep Earth, tracking the deep carbon cycle to >800?km. Understanding the mechanisms of carbon mobilization and freezing is a prerequisite for quantifying the fluxes of carbon in the deep Earth. Here we show direct evidence for the formation of diamond by redox reactions involving FeNi sulfides. Transmission Kikuchi Diffraction identifies an arrested redox reaction from pyrrhotite to magnetite included in diamond. The magnetite corona shows coherent epitaxy with relict pyrrhotite and diamond, indicating that diamond nucleated on magnetite. Furthermore, structures inherited from h-Fe3O4 define a phase transformation at depths of 320 -330?km, the base of the Kaapvaal lithosphere. The oxidation of pyrrhotite to magnetite is an important trigger of diamond precipitation in the upper mantle, explaining the presence of these phases in diamonds.
DS201609-1701
2016
Jacob, D.E.Aulbach, S., Jacob, D.E.Major and trace elements in cratonic mantle eclogites and pyroxenites reveal heterogeneous sources and metamorphic processing of low pressure protoliths.Lithos, Vol. 262, pp. 586-605.MantleEclogite

Abstract: There is a growing body of evidence for the origin of cratonic mantle eclogite xenoliths by low-pressure formation in now-recycled ocean floors. Because they have protoliths ultimately derived from the convecting mantle, their study can potentially yield unprecedented insights into as yet little-understood palaeo-geodynamic regimes, once primary (fractional crystallisation, accumulation, mixing) and secondary processes (kimberlite infiltration, metasomatism) affecting their compositions are understood. This is achieved using diagnostic concentrations or ratios of the analytically and geologically most robust elements (major and minor elements, transition metals, REE), and aided by comparison to natural and modelled analogues. Here, mineral compositions taken from the literature were used to reconstruct bulk rocks and assign the samples to eclogites (further divided into high-Mg, low-Mg and high-Ca types), pyroxenites and their gabbroic (Eu* > 1.05) counterparts. Various protolith types - formed predominantly by < 1 GPa crystallisation from broadly picritic magmas leaving garnet-poor mantle sources - are identified: (1) Many high-Mg eclogites lie on modelled crystallisation trends between 0.5 and < 1 GPa. Some have elevated FeO contents with lower SiO2 and CaO possibly requiring Fe-rich pyroxenite heterogeneities in their mantle source. (2) Many high-Ca eclogites may be the differentiated (higher Na2O, TiO2 and FeO at lower MgO) equivalents of high-Mg eclogites, following modelled crystallisation trends at somewhat lower pressure (0.05 to 0.5 GPa). Other high-Ca eclogites with low FeO were produced during interaction with fluids and melts in mélange-type settings. (3) Low-Mg eclogites, with intermediate MgO content, are too FeO-rich to be intermediary crystallisation products of the same parental melt and are ascribed to melting out of Fe-rich lithologies possibly related to recycling of eclogite and/or contamination with ferromanganese sediments. (4) The positive Eu anomalies in gabbroic eclogites require accumulation of substantial amounts of plagioclase, consistent with their low FeO and TiO2 contents, but their simultaneously low MgO contents suggest that they interacted with residual melts. (5) The elevated CaO and low Al2O3 in pyroxenite may indicate clinopyroxene-rich high- or low-pressure cumulate protoliths, but high Cr2O3 and MgO, combined with low HREE and high LREE in many of these samples, suggests formation by hybridisation of eclogite-derived melt with peridotite.
DS201610-1860
2016
Jacob, D.E.Forster, M.W., Prelevic, D., Schmuck, H.R., Jacob, D.E.Melting and dynamic metasomatism of mixed harzburgite + glimmerite mantle source: implications for the genesis of orogenic potassic magmas.Chemical Geology, in press available 10p.MantleUltrapotassic magmas

Abstract: Tectonically young, orogenic settings are commonly the sites of post-collisional silica-rich ultrapotassic magmas with extreme K2O-contents of up to 9 wt% and K2O/Na2O > 2. Many experimental studies investigating the generation of these melts have concentrated on melting of homogenous phlogopite bearing peridotites, whereas geochemical signatures indicate the involvement of at least two types of source rocks: ultra-depleted and K and trace elements-enriched ones. We report the results of melting experiments at 1-2 GPa of mixed glimmerite and harzburgite, in which these rock types make up two halves each capsule. Melting begins in the glimmerite, and its metasomatic effects on the harzburgite are apparent at 1100 °C even before melt pools are visible. The first melts are Na-rich, seen in zoning of olivines and as growth of clinopyroxene in the harzburgite, but change at higher degrees of melting to produce a typical lamproite-like melt with K2O > 10 wt%. A major advantage of this study is the preservation of distinct melts in different parts of the capsule, which reflect a process of dynamic metasomatism: within the harzburgite matrix, the infiltrating melt derived from melting of the glimmerite changes consistently with the distance of travel through the harzburgite, enabling quantification of the metasomatic effects as an increase in SiO2 and K2O. This results principally from assimilation of orthopyroxene, which increases the Ol/Opx ratio of the residual harzburgite. The effects of quench olivine growth are recognizable and can be quantified due to a step-change in composition at the glimmerite/harzburgite border: the large total surface area of olivine and small melt fraction mean that the amount of quench olivine is high within the harzburgite, but negligible in the almost completely molten glimmerite. Melts of the glimmerite contain up to 8-10 wt% K2O and 53 wt% SiO2, which increase to 55-56 wt% after interaction with the harzburgite. Mediterranean lamproites resemble melts of glimmerite, whereas melts that have interacted with harzburgite are more similar to less potassic, but more SiO2-rich shoshonites of the Mediterranean region.
DS201705-0877
2017
Jacob, D.E.Sommer, H., Jacob, D.E., Stern, R.A., Petts, D., Mattey, D.P., Pearson, D.G.Fluid induced transition from banded kyanite to bimineralic eclogite and implications for the evolution of cratons.Geochimica et Cosmochimica Acta, in press available 55p.Africa, South AfricaDeposit - Roberts Victor

Abstract: Heterogeneous, modally banded kyanite-bearing and bimineralic eclogites from the lithospheric mantle, collected at the Roberts Victor Diamond mine (South Africa), show a reaction texture in which kyanite is consumed. Geothermobarometric calculations using measured mineral compositions in Perple_X allowed the construction of a P-T path showing a steep, cool prograde metamorphic gradient of 2 °C/km to reach peak conditions of 5.8 GPa and 890 °C for the kyanite eclogite. The kyanite-out reaction formed bimineralic eclogite and is probably an integral part of the mineralogical evolution of most archetypal bimineralic eclogites at Roberts Victor and potentially elsewhere. The kyanite-out reaction occured at close to peak pressure (5.3 GPa) and was associated with a rise in temperature to 1380 °C. Mass balance calculations show that upon breakdown, the kyanite component is fully accommodated in garnet and omphacite via a reaction system with low water fugacity that required restricted fluid influx from metasomatic sources. The ?18O values of garnets are consistently higher than normal mantle values. Each sample has its characteristic trend of ?18O variance between garnets in the kyanite-bearing sections and those in the bimineralic parts covering a range between 5.1‰ and 6.8‰. No systematic change in O-isotope signature exists across the sample population. Differences in garnet trace element signatures between differing lithologies in the eclogites are significant. Grossular-rich garnets coexisting with kyanite have strong positive Eu-anomalies and low Gd/Yb ratios, while more pyrope-rich garnets in the bimineralic sections have lost their positive Eu-anomaly, have higher Gd/Yb ratios and generally higher heavy rare earth element contents. Garnets in the original kyanite-bearing portions thus reflect the provenance of the rocks as metamorphosed gabbros/troctolites. The kyanite-out reaction was most likely triggered by a heating event in the subcratonic lithosphere. As kyanite contains around 100 ppm of H2O it is suggested that the kyanite-out reaction, once initiated by heating and restricted metasomatic influx, was promoted by the release of water contained in the kyanite. The steep (high-P low-T) prograde P-T path defining rapid compression at low heating rates is atypical for subduction transport of eclogites into the lithospheric mantle. Such a trajectory is best explained in a model where strong lateral compression forces eclogites downward to higher pressures, supporting models of cratonic lithosphere formation by lateral collision and compression.
DS201707-1323
2017
Jacob, D.E.Forster, M.W., Orelevic, D., Schmuck, H.R., Buhre, S., Veter, M., Mertz-Kraus, R., Foley, S.F., Jacob, D.E.Melting and dynamic metasomatism of mixed harzburgite + glimmerite mantle source: implications for the genesis of orogenic potassic magmas.Chemical Geology, Vol. 455, pp. 182-191.Mantlemetasomatism

Abstract: Tectonically young, orogenic settings are commonly the sites of post-collisional silica-rich ultrapotassic magmas with extreme K2O-contents of up to 9 wt% and K2O/Na2O > 2. Many experimental studies investigating the generation of these melts have concentrated on melting of homogenous phlogopite bearing peridotites, whereas geochemical signatures indicate the involvement of at least two types of source rocks: ultra-depleted and K and trace elements-enriched ones. We report the results of melting experiments at 1–2 GPa of mixed glimmerite and harzburgite, in which these rock types make up two halves each capsule. Melting begins in the glimmerite, and its metasomatic effects on the harzburgite are apparent at 1100 °C even before melt pools are visible. The first melts are Na-rich, seen in zoning of olivines and as growth of clinopyroxene in the harzburgite, but change at higher degrees of melting to produce a typical lamproite-like melt with K2O > 10 wt%. A major advantage of this study is the preservation of distinct melts in different parts of the capsule, which reflect a process of dynamic metasomatism: within the harzburgite matrix, the infiltrating melt derived from melting of the glimmerite changes consistently with the distance of travel through the harzburgite, enabling quantification of the metasomatic effects as an increase in SiO2 and K2O. This results principally from assimilation of orthopyroxene, which increases the Ol/Opx ratio of the residual harzburgite. The effects of quench olivine growth are recognizable and can be quantified due to a step-change in composition at the glimmerite/harzburgite border: the large total surface area of olivine and small melt fraction mean that the amount of quench olivine is high within the harzburgite, but negligible in the almost completely molten glimmerite. Melts of the glimmerite contain up to 8–10 wt% K2O and 53 wt% SiO2, which increase to 55–56 wt% after interaction with the harzburgite. Mediterranean lamproites resemble melts of glimmerite, whereas melts that have interacted with harzburgite are more similar to less potassic, but more SiO2-rich shoshonites of the Mediterranean region.
DS201709-1956
2017
Jacob, D.E.Aulbach, S., Jacob, D.E., Cartigny, P., Stern, R.A., Simonetti, S.S., Worner, G., Viljoen, K.S.Eclogite xenoliths from Orapa: ocean crust recycling, mantle metasomatism and carbon cycling at the western Zimbabwe craton margin.Geochimica et Cosmochimica Acta, Vol. 213, pp. 574-592.Africa, Botswanadeposit - Orapa

Abstract: Major- and trace-element compositions of garnet and clinopyroxene, as well as 87Sr/86Sr in clinopyroxene and ?18O in garnet in eclogite and pyroxenite xenoliths from Orapa, at the western margin of the Zimbabwe craton (central Botswana), were investigated in order to trace their origin and evolution in the mantle lithosphere. Two groups of eclogites are distinguished with respect to 87Sr/86Sr: One with moderate ratios (0.7026-0.7046) and another with 87Sr/86Sr >0.7048 to 0.7091. In the former group, heavy ?18O attests to low-temperature alteration on the ocean floor, while 87Sr/86Sr correlates with indices of low-pressure igneous processes (Eu/Eu?, Mg#, Sr/Y). This suggests relatively undisturbed long-term ingrowth of 87Sr at near-igneous Rb/Sr after metamorphism, despite the exposed craton margin setting. The high-87Sr/86Sr group has mainly mantle-like ?18O and is suggested to have interacted with a small-volume melt derived from an aged phlogopite-rich metasome. The overlap of diamondiferous and graphite-bearing eclogites and pyroxenites over a pressure interval of ?3.2 to 4.9 GPa is interpreted as reflecting a mantle parcel beneath Orapa that has moved out of the diamond stability field, due to a change in geotherm and/or decompression. Diamondiferous eclogites record lower median 87Sr/86Sr (0.7039) than graphite-bearing samples (0.7064) and carbon-free samples (0.7051), suggesting that interaction with the - possibly oxidising - metasome-derived melt caused carbon removal in some eclogites, while catalysing the conversion of diamond to graphite in others. This highlights the role of small-volume melts in modulating the lithospheric carbon cycle. Compared to diamondiferous eclogites, eclogitic inclusions in diamonds are restricted to high FeO and low SiO2, CaO and Na2O contents, they record higher equilibrium temperatures and garnets have mostly mantle-like O isotopic composition. We suggest that this signature was imparted by a sublithospheric melt with contributions from a clinopyroxene-rich source, possibly related to the ca. 2.0 Ga Bushveld event.
DS201709-2003
2017
Jacob, D.E.Jacob, D.E., Stern, R.A., Chapman, J., Piazoli, S.Insights into diamond formation from polycrystalline diamond aggregates. DiamonditesGoldschmidt Conference, abstract 1p.Africa, South Africadeposit - Venetia

Abstract: Polycrystalline diamond aggregates (diamondites) are produced by rapid crystal nucleation caused by extreme carbon supersaturation in mantle fluids. They may form episodically and under variable chemical conditions, providing snapshots of diamond formation in the Earth’s mantle. Diamondites, thus, represent an extreme end member of diamond formation mechanisms, while forming via the same processes and ingredients as the gem-sized diamonds. We present results on a large suite of diamondites from the Venetia mine (South Africa), comprising a complete characterisation of the diamonds and their silicate inclusions and intergrowths. The highlighted characteristic of this sample suite is its heterogeneity in all aspects, from affiliated silicate to diamond composition and texture of the diamond aggregates. The diamond grains in the samples are intergrown with silicates (garnets, clinopyroxenes, phlogopites) comprising a websteritic-eclogitic and a peridotiticpyroxenitic suite of minerals. Diamonds, regardless of their affiliation based on their silicate phases, overlap in carbon and nitrogen composition and have ?13C values between -28 and -8 ‰, ?15N values of 0.8 to 16.3 ‰ and nitrogen contents of 4 to 2329 ppm. The entire range of carbon and nitrogen variability of the suite is also reflected in some individual samples. Cathodoluminescence imaging visualizes different zones in the samples that can be interpreted as different growth events with differing nitrogen contents and ?15N decoupled from ?13C values, in line with the variability off nitrogen aggregation states. Electron backscatter diffraction analyses identify an original texture of randomly intergrown diamond grains that is partly changed by deformation and newly grown smaller diamond grains. The large overall variability suggesting episodic formation of diamondite with nitrogen from crustal sources.
DS201709-2056
2017
Jacob, D.E.Sommer, H., Jacob, D.E., Stern, R.A., Petts, D., Mattey, D.P., Pearson, D.G.Fluid induced transition from banded kyanite to bimineralic eclogite and implications for the evolution of cratons.Goldschmidt Conference, abstract 1p.Africa, South Africadeposit - Roberts Victor

Abstract: Heterogeneous, modally banded kyanite-bearing and bimineralic eclogites from the lithospheric mantle, collected at the Roberts Victor Diamond mine (South Africa), show a reaction texture in which kyanite is consumed. Geothermobarometric calculations using measured mineral compositions in Perple_X allowed the construction of a P-T path showing a steep, cool prograde metamorphic gradient of 2 °C/km to reach peak conditions of 5.8 GPa and 890 °C for the kyanite eclogite. The kyanite-out reaction formed bimineralic eclogite and is probably an integral part of the mineralogical evolution of most archetypal bimineralic eclogites at Roberts Victor and potentially elsewhere. The kyanite-out reaction occured at close to peak pressure (5.3 GPa) and was associated with a rise in temperature to 1380 °C. Mass balance calculations show that upon breakdown, the kyanite component is fully accommodated in garnet and omphacite via a reaction system with low water fugacity that required restricted fluid influx from metasomatic sources. The ?18O values of garnets are consistently higher than normal mantle values. Each sample has its characteristic trend of ?18O variance between garnets in the kyanite-bearing sections and those in the bimineralic parts covering a range between 5.1‰ and 6.8‰. No systematic change in O-isotope signature exists across the sample population. Differences in garnet trace element signatures between differing lithologies in the eclogites are significant. Grossular-rich garnets coexisting with kyanite have strong positive Eu-anomalies and low Gd/Yb ratios, while more pyrope-rich garnets in the bimineralic sections have lost their positive Eu-anomaly, have higher Gd/Yb ratios and generally higher heavy rare earth element contents. Garnets in the original kyanite-bearing portions thus reflect the provenance of the rocks as metamorphosed gabbros/troctolites. The kyanite-out reaction was most likely triggered by a heating event in the subcratonic lithosphere. As kyanite contains around 100 ppm of H2O it is suggested that the kyanite-out reaction, once initiated by heating and restricted metasomatic influx, was promoted by the release of water contained in the kyanite. The steep (high-P low-T) prograde P-T path defining rapid compression at low heating rates is atypical for subduction transport of eclogites into the lithospheric mantle. Such a trajectory is best explained in a model where strong lateral compression forces eclogites downward to higher pressures, supporting models of cratonic lithosphere formation by lateral collision and compression.
DS201710-2212
2017
Jacob, D.E.Aulbach, S., Jacob, D.E., Cartigny, P., Stern, R.A., Simonetti, S.S., Womer, G., Viljoen, K.S.Eclogite xenoliths from Orapa: Ocean crust recycling, mantle metasomatism and carbon cycling at the western Zimbabwe craton margin.Geochimica et Cosmochinica Acta, Vol. 213, pp. 574-592.Africa, Botswanadeposit - Orapa

Abstract: Major- and trace-element compositions of garnet and clinopyroxene, as well as 87Sr/86Sr in clinopyroxene and ?18O in garnet in eclogite and pyroxenite xenoliths from Orapa, at the western margin of the Zimbabwe craton (central Botswana), were investigated in order to trace their origin and evolution in the mantle lithosphere. Two groups of eclogites are distinguished with respect to 87Sr/86Sr: One with moderate ratios (0.7026-0.7046) and another with 87Sr/86Sr >0.7048 to 0.7091. In the former group, heavy ?18O attests to low-temperature alteration on the ocean floor, while 87Sr/86Sr correlates with indices of low-pressure igneous processes (Eu/Eu?, Mg#, Sr/Y). This suggests relatively undisturbed long-term ingrowth of 87Sr at near-igneous Rb/Sr after metamorphism, despite the exposed craton margin setting. The high-87Sr/86Sr group has mainly mantle-like ?18O and is suggested to have interacted with a small-volume melt derived from an aged phlogopite-rich metasome. The overlap of diamondiferous and graphite-bearing eclogites and pyroxenites over a pressure interval of ?3.2 to 4.9 GPa is interpreted as reflecting a mantle parcel beneath Orapa that has moved out of the diamond stability field, due to a change in geotherm and/or decompression. Diamondiferous eclogites record lower median 87Sr/86Sr (0.7039) than graphite-bearing samples (0.7064) and carbon-free samples (0.7051), suggesting that interaction with the - possibly oxidising - metasome-derived melt caused carbon removal in some eclogites, while catalysing the conversion of diamond to graphite in others. This highlights the role of small-volume melts in modulating the lithospheric carbon cycle. Compared to diamondiferous eclogites, eclogitic inclusions in diamonds are restricted to high FeO and low SiO2, CaO and Na2O contents, they record higher equilibrium temperatures and garnets have mostly mantle-like O isotopic composition. We suggest that this signature was imparted by a sublithospheric melt with contributions from a clinopyroxene-rich source, possibly related to the ca. 2.0 Ga Bushveld event.
DS201804-0689
2018
Jacob, D.E.Forster, M.W., Prelevic, D., Schmuck, H.R., Buhre, S., Marschall, H.R., Mertz-Kraus, R., Jacob, D.E.Melting phologopite rich MARID: lamproites and the role of alkalis in olivine liquid Ni partioning.Chemical Geology, Vol. 476, 1, pp. 429-440.Technologylamproites

Abstract: In this study, we show how veined lithospheric mantle is involved in the genesis of ultrapotassic magmatism in cratonic settings. We conducted high pressure experiments to simulate vein + wall rock melting within the Earth's lithospheric mantle by reacting assemblages of harzburgite and phlogopite-rich hydrous mantle xenoliths. These comprised a mica-, amphibole-, rutile-, ilmenite-, diopside (MARID) assemblage at 3-5 GPa and 1325-1450 °C. Melting of the MARID assemblages results in infiltration of melt through the harzburgite, leading to its chemical alteration. At 3 and 4 GPa, melts are high in K2O (> 9 wt%) with K2O/Na2O > > 2 comparable to anorogenic lamproites. Higher pressures and temperatures (5 GPa/1450 °C) lead to increasing MgO contents of the melt and to some extent lower K2O contents (5-7 wt%) at equally high K2O/Na2O ratios. Our experiments provide insights into the role of alkalis in nickel-partitioning (DNi) between olivine and ultrapotassic melt. We observe that the high contents of Na, K, and Al are indicative of high DNi values, implying that the melt polymerization is the dominant factor influencing the olivine/melt nickel partitioning. The change of DNi as a function of melt composition results in a pressure independent, empirical geothermometer: Element oxides represent the composition of the glass (in wt%), and DNi is the liquid/olivine Ni-partitioning coefficient. We propose that this geothermometer is applicable to all natural silicate melts that crystallized olivine in a temperature interval between 1000 and 1600 °C. Application to glass-olivine pairs from calc-alkaline settings (Mexico), MORB (East Pacific Rise), and OIB (Hawaii) yielded reasonable values of 996-1199 °C, 1265 °C, and 1330 °C, respectively.
DS201809-1991
2017
Jacob, D.E.Aulbach, S., Jacob, D.E., Cartigny, P., Stern, R.A., Simonetti, S.S., Worner, G., Viljoen, K.S.Eclogite xenoliths from Orapa: Ocean crust recycling, mantle metasomatism and carbon cycling at the western Zimbabwe craton margin.Geochimica et Cosmochimica Acta, Vol. 213, 1, pp. 574-592.Africa, Botswanadeposit - Orapa

Abstract: Major- and trace-element compositions of garnet and clinopyroxene, as well as 87Sr/86Sr in clinopyroxene and ?18O in garnet in eclogite and pyroxenite xenoliths from Orapa, at the western margin of the Zimbabwe craton (central Botswana), were investigated in order to trace their origin and evolution in the mantle lithosphere. Two groups of eclogites are distinguished with respect to 87Sr/86Sr: One with moderate ratios (0.7026-0.7046) and another with 87Sr/86Sr >0.7048 to 0.7091. In the former group, heavy ?18O attests to low-temperature alteration on the ocean floor, while 87Sr/86Sr correlates with indices of low-pressure igneous processes (Eu/Eu?, Mg#, Sr/Y). This suggests relatively undisturbed long-term ingrowth of 87Sr at near-igneous Rb/Sr after metamorphism, despite the exposed craton margin setting. The high-87Sr/86Sr group has mainly mantle-like ?18O and is suggested to have interacted with a small-volume melt derived from an aged phlogopite-rich metasome. The overlap of diamondiferous and graphite-bearing eclogites and pyroxenites over a pressure interval of ?3.2 to 4.9 GPa is interpreted as reflecting a mantle parcel beneath Orapa that has moved out of the diamond stability field, due to a change in geotherm and/or decompression. Diamondiferous eclogites record lower median 87Sr/86Sr (0.7039) than graphite-bearing samples (0.7064) and carbon-free samples (0.7051), suggesting that interaction with the - possibly oxidising - metasome-derived melt caused carbon removal in some eclogites, while catalysing the conversion of diamond to graphite in others. This highlights the role of small-volume melts in modulating the lithospheric carbon cycle. Compared to diamondiferous eclogites, eclogitic inclusions in diamonds are restricted to high FeO and low SiO2, CaO and Na2O contents, they record higher equilibrium temperatures and garnets have mostly mantle-like O isotopic composition. We suggest that this signature was imparted by a sublithospheric melt with contributions from a clinopyroxene-rich source, possibly related to the ca. 2.0 Ga Bushveld event.
DS201809-2044
2018
Jacob, D.E.Jacob, D.E., Stern, R.A., Stachel, T., Piazolo, S.Polycrystalline diamonds and their mantle derived mineral and fluid intergrowths. (Aggregates, framesites, boart, diamondite)Goldschmidt Conference, 1p. AbstractAfrica, South Africadeposit - Venetia

Abstract: Polycrystalline diamond aggregates (framesites, boart, diamondite) are an understudied variety of mantle diamond, but can make up 20% of the production in some Group I kimberlites. Their polycrystalline nature indicates rapid precipitation from carbon-oversaturated fluids and individual PDAs often contain a chemically heterogeneous suite of websteritic and pyroxenitic inclusions and minerals intimately intergrown with the diamond crystals. Geochemical and microstructural evidence suggests that fluid-driven redox reactions with lithospheric material occurring episodically over millions of years play a major role in freezing carbon in the subcratonic lithosphere (Jacob et al., 2000; 2016; Mikhail et al., 2014). A suite of 39 samples from the Venetia kimberlite pipe in South Africa allows a more detailed look at the diamondforming fluids. 13C values in the diamonds measured by secondary ion mass spectrometry range from +2 to -28 and cover the entire range for PDA from the literature. Nitrogen concentrations are mostly very low (less than 100 at ppm), but reach up to 2660 at ppm in individual samples. These high nitrogen concentrations in concert with mostly positive 15N values of up to +17 and some very negative 3C values suggest crustal material as the source of the nitrogen and the carbon. However, detailed analysis of the sample provides evidence for a more complex growth history followed by alteration. Individual diamond crystals show complex growth zonations by cathodoluminescence imaging that can be related with the carbon and nitrogen isotopic compositions and points to growth incorporating several pulses of carbon-nitrogen fluid with distinct isotopic compositions. Most of these growth events show decoupled carbon and nitrogen systematics. In addition, EBSD identifies deformation and recrystallization and nitrogen aggregation states range from pure IaA to pure IaB, supporting a heterogeneous and episodic growth history.
DS201810-2307
2018
Jacob, D.E.Cruz-Uribe, A.M., Feineman, M.D., Zack, T., Jacob, D.E.Asssessing trace element (dis) equilibrium and the application of single element thermometers in metamorphic rocks.Lithos, Vol. 314-315, pp. 1-15.Globalthermobarometry

Abstract: Empirical and experimental calibration of single element solubility thermometers, such as Zr-in-rutile, Zr-in-titanite, Ti-in-zircon, and Ti-in-quartz, within the past 13 years has greatly expanded our ability to assess the pressure and temperature conditions of individual minerals associated with specific textures in metamorphic rocks. Combined with advances in in situ techniques for analyzing trace concentrations, this has led to an increase in the combined use of single element thermometers, geochronometers, and isotope ratios, often simultaneously, in metamorphic minerals. Here we review the calibration and application of single element thermometers at the pressure and temperature conditions of interest in metamorphic rocks. We discuss to what extent accessory phase equilibrium and trace element equilibrium are attained in metamorphic systems, and the thermodynamic and kinetic framework within which trace element equilibrium is assessed. As an example, we present a comprehensive study of trace element distribution during rutile replacement by titanite in rocks that experienced high-temperature amphibolite-facies overprinting and those that underwent low-temperature blueschist-facies overprinting from a variety of subduction-related terranes worldwide. We find that trace element distributions approach equilibrium partition coefficients in rocks from amphibolite-facies overprinted terranes, whereas trace element distributions do not approach equilibrium in rocks that experienced blueschist-facies overprinting. We caution that single element thermometers that rely upon slow-diffusing high field strength elements should not be applied to rocks equilibrated at <600 °C unless attainment of trace element equilibrium can be demonstrated.
DS201812-2776
2019
Jacob, D.E.Aulbach, S., Heaman, L.M., Jacob, D.E., Viljoen, K.S.Ages and sources of mantle eclogites: ID-TIMS and in situ MC-ICPMS Pb-Sr isotope sytematics of clinopyroxene.Chemical Geology, Vol. 503, pp. 15-28.Mantleeclogite

Abstract: Strontium and Pb isotopic compositions of clinopyroxene (cpx) in selected samples from three well-characterised eclogite suites with oceanic crustal protoliths (Lace/Kaapvaal craton, Orapa/Zimbabwe craton and Koidu/West African craton) were acquired by high-precision isotope dilution thermal ionisation mass spectrometry (ID-TIMS) and in situ multicollector-laser ablation-inductively-coupled plasma mass spectrometry (MC-LA-ICPMS). The aims of this study are twofold: (1) assess their utility to obtain formation or resetting age constraints and identify elemental signatures that enhance the chances of successful age dating, and (2) to confirm the veracity and utility of results obtained by novel MC-LA-ICPMS techniques. Strontium-Pb isotope systematics of eclogitic cpx measured in this study are decoupled and may reflect addition of unsupported radiogenic Sr during seawater alteration or interaction with oceanic sediments in subduction mélanges, and/or disturbance due to mantle metasomatism, to which the more incompatible Pb is more susceptible. Despite a complex history, subsets of samples yield meaningful model dates. Clinopyroxene fractions from Lace with high Pb contents (36?ppm), unradiogenic Pb isotopic compositions (206Pb/204Pb?=?13.5713.52) and low 238U/204Pb (1.01.5) give single-stage model Pb dates of 2.902.84?Ga. In contrast, samples from Orapa plot to the right of the Geochron and do not yield meaningful Pb model ages. However, these data do define secondary isochrons that can be modelled to yield minimum age constraints on major events affecting the cratonic lithosphere. Within the uncertainties, the resultant 2.18?±?0.45?Ga age obtained for Koidu eclogites reflect disturbance of the Pb isotope system due to subduction beneath the craton linked to the Eburnean orogeny, while they retained their unradiogenic 87Sr/86Sr (0.7016). Similarly, the age for samples from Orapa (2.20?±?0.54?Ga) is interpreted as an overprint age related to Palaeoproterozoic accretion at the western craton margin. Gabbroic eclogites (Eu/Eu*?>?1) with plagioclase-rich protoliths having low time-integrated Rb/Sr and U/Pb retain the least radiogenic Sr and, in part, Pb. High model ? (9.0 to 9.1) for several eclogites from Lace with elevated LREE, Th and Pb abundances reflects ca. 3.0?Ga addition of a sedimentary component, possibly derived from reworking of a high-? basaltic protocrust, as observed on other cratons. We suggest that sample targeting can be usefully guided by fast-throughput in situ LA-ICPMS techniques, which largely yield results identical to ID-TIMS, albeit at lower precision, and which can further help identify kimberlite contamination in the mineral separates used for solution work.
DS201905-1062
2019
Jacob, D.E.Nestola, F., Jacob, D.E., Pamato, M.G., Pasqualatto, L., Oliveira, B., Greene, S., Perritt, S., Chinn, I., Milani, S., Kueter, N., Sgreva, N., Nimis, P., Secco, L., Harris, J.W.Protogenetic garnet inclusions and the age of diamonds.Geology, doi.10.1130/G45781.1Mantlediamond inclusions

Abstract: Diamonds are the deepest accessible “fragments” of Earth, providing records of deep geological processes. Absolute ages for diamond formation are crucial to place these records in the correct time context. Diamond ages are typically determined by dating inclusions, assuming that they were formed simultaneously with their hosts. One of the most widely used mineral inclusions for dating diamond is garnet, which is amenable to Sm-Nd geochronology and is common in lithospheric diamonds. By investigating worldwide garnet-bearing diamonds, we provide crystallographic evidence that garnet inclusions that were previously considered to be syngenetic may instead be protogenetic, i.e., they were formed before the host diamond, raising doubts about the real significance of many reported diamond “ages.” Diffusion modeling at relevant pressures and temperatures, however, demonstrates that isotopic resetting would generally occur over geologically short time scales. Therefore, despite protogenicity, the majority of garnet-based ages should effectively correspond to the time of diamond formation. On the other hand, our results indicate that use of large garnet inclusions (e.g., >100 ?m) and diamond hosts formed at temperatures lower than ?1000 °C is not recommended for diamond age determinations.
DS201912-2825
2020
Jacob, D.E.Shirey, S.B., Smit, K.V., Pearson, D.G., Walter, M.J., Aulbach, S., Brenker, F.E., Bureau, H., Burnham, A.D., Cartigny, P., Chacko, T., Frost, D.J., Hauri, E.H., Jacob, D.E., Jacobsen, S.D., Kohn, S.C., Luth, R.W., Mikhail, S., Navon, O., Nestola, F., NimDiamonds and the mantle geodynamics of carbon: deep mantle carbon and evolution from the diamond record.IN: Deep carbon: past to present, Orcutt, Daniel, Dasgupta eds., pp. 89-128.Mantlegeodynamics

Abstract: The science of studying diamond inclusions for understanding Earth history has developed significantly over the past decades, with new instrumentation and techniques applied to diamond sample archives revealing the stories contained within diamond inclusions. This chapter reviews what diamonds can tell us about the deep carbon cycle over the course of Earth’s history. It reviews how the geochemistry of diamonds and their inclusions inform us about the deep carbon cycle, the origin of the diamonds in Earth’s mantle, and the evolution of diamonds through time.
DS202001-0039
2020
Jacob, D.E.Shirey, S.B., Smit, K.V., Pearson, D.G., Walter, M.J., Aulbach, S., Brenker, F.E., Bureau, H., Burnham, A.D., Cartigny, P., Chacko, T., Frost, D.J., Hauri, E.H., Jacob, D.E., Jacobsen, S.D., Kohn, S.C., Luth, R.W., Mikhail, S., Navon, O., Nestola, F., NimDiamonds and mantle geodynamics of carbon: IN: Deep Carbon: past to present. Editors Orcutt, Danielle, Dasgupta, pp. 89-128.Mantlegeodynamics

Abstract: The science of studying diamond inclusions for understanding Earth history has developed significantly over the past decades, with new instrumentation and techniques applied to diamond sample archives revealing the stories contained within diamond inclusions. This chapter reviews what diamonds can tell us about the deep carbon cycle over the course of Earth’s history. It reviews how the geochemistry of diamonds and their inclusions inform us about the deep carbon cycle, the origin of the diamonds in Earth’s mantle, and the evolution of diamonds through time.
DS202004-0519
2020
Jacob, D.E.Howell, D., Stachel, T., Stern, R.A., Pearson, D.G., Nestola, F., Hardman, M.F., Harris, J.W., Jaques, A.L., Shirery, S.B., Cartigny, P., Smit, K.V., Aulbach, S., Brenker, F.E., Jacob, D.E., Thomassot, E., Walter, M.J., Navon, O.Deep carbon through time: Earth's diamond record and its implications for carbon cycling and fluid speciation in the mantle.(peridotite and eclogite used)Geochimica et Cosmochimica Acta, Vol. 275, pp. 99-122.Mantlecarbon

Abstract: Diamonds are unrivalled in their ability to record the mantle carbon cycle and mantle fO2 over a vast portion of Earth’s history. Diamonds’ inertness and antiquity means their carbon isotopic characteristics directly reflect their growth environment within the mantle as far back as ?3.5 Ga. This paper reports the results of a thorough secondary ion mass spectrometry (SIMS) carbon isotope and nitrogen concentration study, carried out on fragments of 144 diamond samples from various locations, from ?3.5 to 1.4 Ga for P [peridotitic]-type diamonds and 3.0 to 1.0 Ga for E [eclogitic]-type diamonds. The majority of the studied samples were from diamonds used to establish formation ages and thus provide a direct connection between the carbon isotope values, nitrogen contents and the formation ages. In total, 908 carbon isotope and nitrogen concentration measurements were obtained. The total ?¹³C data range from ?17.1 to ?1.9 ‰ (P = ?8.4 to ?1.9 ‰; E = ?17.1 to ?2.1‰) and N contents range from 0 to 3073 at. ppm (P = 0 to 3073 at. ppm; E = 1 to 2661 at. ppm). In general, there is no systematic variation with time in the mantle carbon isotope record since > 3 Ga. The mode in ?¹³C of peridotitic diamonds has been at ?5 (±2) ‰ since the earliest diamond growth ?3.5 Ga, and this mode is also observed in the eclogitic diamond record since ?3 Ga. The skewness of eclogitic diamonds’ ?¹³C distributions to more negative values, which the data establishes began around 3 Ga, is also consistent through time, with no global trends apparent. No isotopic and concentration trends were recorded within individual samples, indicating that, firstly, closed system fractionation trends are rare. This implies that diamonds typically grow in systems with high excess of carbon in the fluid (i.e. relative to the mass of the growing diamond). Any minerals included into diamond during the growth process are more likely to be isotopically reset at the time of diamond formation, meaning inclusion ages would be representative of the diamond growth event irrespective of whether they are syngenetic or protogenetic. Secondly, the lack of significant variation seen in the peridotitic diamonds studied is in keeping with modeling of Rayleigh isotopic fractionation in multicomponent systems (RIFMS) during isochemical diamond precipitation in harzburgitic mantle. The RIFMS model not only showed that in water-maximum fluids at constant depths along a geotherm, fractionation can only account for variations of <1‰, but also that the principal ?¹³C mode of ?5 ± 1‰ in the global harzburgitic diamond record occurs if the variation in fO2 is only 0.4 log units. Due to the wide age distribution of P-type diamonds, this leads to the conclusion that the speciation and oxygen fugacity of diamond forming fluids has been relatively consistent. The deep mantle has therefore generated fluids with near constant carbon speciation for 3.5 Ga.
DS202008-1398
2020
Jacob, D.E.Greene, S., Jacob, D.E., O'Reilly, S.Y., Henry, H., Pinter, Z., Heaman, L.Extensive prekimberlitic lithosphere modification recorded in Jericho mantle xenoliths in kimberlites, Slave Craton.Goldschmidt 2020, 1p. AbstractCanada, Northwest Territoriesdeposit - Jericho

Abstract: Wehrlite and pyroxenite xenoliths and megacrysts from the Jericho kimberlite were analyzed by ?XRF and EBSD, and for major elements, trace elements, and isotopes (Pb-Sr- O) in major phases. Thermobarometry places these samples at 60 - 180 km and 600 - 1200 ??C. While modes and textures vary, many samples have olivine-olivine grain boundaries with straight edges and 120° angle junctions, indicating granoblastic recrystallisation, while clinopyroxene and orthopyroxene are complexly intergrown. Clinopyroxene twins and subgrains recording orientations distinct from the encapsulating grain were detected using EBSD and are inferred to represent recent modification processes. Several distinct garnet compositions were measured, with multiple thin garnet rims in some samples suggesting possible successive stages of garnet crystallisation. Complex chromium zoning in garnet is detected by ?XRF in several samples (fig.1). Pb-Pb ages for most samples are similar to the age of kimberlite entrainment (173 Ma), but the shallowest pyroxenite sample preserves the most radiogenic Pb composition, intercecting concordia at 0.7 - 1.1 Ga, and is the only sample with ?18O above the mantle range (6.2±0.1 ‰). The deepest sample has the lowest ?18O (5.5±0.1 ‰) and radiogenic 87Sr/86Sr similar to MARID rocks (0.709±1 ‰). These results suggest the Jericho lithosphere experienced several melt/fluid injection events that modified substantial portions of the sampled section soon before kimberlite entrainment.
DS202102-0212
2021
Jacob, D.E.Otter, L.M., Forster, M.W., Belousova, E., O'Reilly, P., Nowak, D., Parlk, S., Clar, S., Foley, S.F., Jacob, D.E.GGR cutting-edge review nanoscale chemical imaging by photo-induced force microscopy: technical aspects and application to the geosciences. ( not specific to diamonds)Geostandards and Geoanalytical Research, doi:10.111/ GGR.12373. 51p. PdfGlobalspectroscopy, mineralogy

Abstract: Photo?induced force microscopy (PiFM) is a new?frontier technique that combines the advantages of atomic force microscopy with infrared spectroscopy and allows for the simultaneous acquisition of 3D topographic data with molecular chemical information at high spatial (~ 5 nm) and spectral (~ 1 cm?1) resolution at the nanoscale. This non?destructive technique is time efficient as it requires only conventional mirror?polishing and has fast mapping rates on the order of a few minutes that allow the study of dynamic processes via time series. Here, we review the method’s historical development, working principle, data acquisition, evaluation, and provide a comparison with traditional geochemical methods. We review PiFM studies in the areas of materials science, chemistry, and biology. In addition, we provide the first applications for geochemical samples including the visualisation of faint growth zonation in zircons, the identification of fluid speciation in high?pressure experimental samples, and of nanoscale organic phases in biominerals. We demonstrate that PiFM analysis is a time? and cost?efficient technique combining high?resolution surface imaging with molecular chemical information at the nanoscale and, thus, complements and expands traditional geochemical methods.
DS202107-1128
2019
Jacob, D.E.Shirey, S.B., Smit, K.V., Pearson, D.G., Walter, M.J., Aulbach, S., Brenker, F.E., Bureau, H., Burnham, A.D., Cartigny, P., Chacko, T., Frost, D.J., Hauri, E.H., Jacob, D.E., Jacobsen, S.D., Kohn, S.C., Luth, R.W., Mikhail, S., Navon, O.. Nestola, F., NimDiamonds and mantle geodynamics of carbon.Deep Carbon - Cambridge University Press , Cambridge.org 40p. PdfMantlecarbon
DS1987-0314
1987
Jacob, H.L.Jacob, H.L.Inventaire des gisements de mineraux industriels off rant un potentiel pourla production de minerales.Quebec Department of Mines, MB 87-43, 68p.QuebecIndustrial minerals
DS1998-0677
1998
Jacob, H.L.Jacob, H.L.Caracterisation de gites de syenite a nepheline comme source de materiaux feldspathiques.Quebec Department of Mines, DP 98-05, p. 52.QuebecGeology, nepheline syenite
DS200612-0632
2006
Jacob, J.Jacob, J., Ward, J.D., Bluck, B.J., Scholz, R.A., Frimmel, H.E.Some observations on Diamondiferous bedrock gully trapsites on Late Cainozoic, marine cut platforms of the Sperrgebiet, Namibia.Ore Geology Reviews, Vol. 28, 4, pp. 493-506.Africa, NamibiaGeomorphology, alluvials, placers
DS201412-0417
2014
Jacob, J.Jacob, J.The Namibian megaplacer: 106 years on and still going strong.GSSA Kimberley Diamond Symposium and Trade Show provisional programme, Sept. 11, title onlyAfrica, NamibiaAlluvials
DS201412-0418
2014
Jacob, J.Jacob, J., Prins, C., Oelofsen, A.Determination of sampling configuration for near shore Diamondiferous gravel occurrence using geostatistical methods. Mining area no. 1 - linear beach NamdebJournal of South African Institute of Mining and Metallurgy, Vol. 114, Jan. pp. 31-38.Africa, NamibiaSampling - geostatistics
DS201605-0849
2016
Jacob, J.Jacob, J.Using the proportion of barren samples as a proxy for minimum grade in a Diamondiferous linear beach deposit - an application of the Nachman model.Diamonds Still Sparkling SAIMM 2016 Conference, Mar. 14-17, pp. 47-56.Africa, NamibiaGeostatistics
DS201609-1716
2016
Jacob, J.De Wit, M., Bhebhe, Z., Davidson, J., Haggerty, S.E., Hundt, P., Jacob, J., Lynn, M., Marshall, T.R., Skinner, C., Smithson, K., Stiefenhofer, J., Robert, M., Revitt, A., Spaggiari, R., Ward, J.Overview of diamonds resources in Africa.Episodes, Vol. 9, 2, pp. 198-238.AfricaDiamond resources - overview

Abstract: From the discovery of diamonds in South Africa in 1866 until the end of 2013, Africa is estimated to have produced almost 3.2 Bct out of a total global production of 5.03 Bct, or 63.6% of all diamonds that have ever been mined. In 2013 African countries ranked 2nd (Botswana), 3rd (DRC), 6th (Zimbabwe), 7th (Angola), 8th (South Africa), and 9th (Namibia), in terms of carat production and 1st (Botswana), 4th (Namibia), 5th (Angola), 6th (South Africa), 7th (Zimbabwe), and 9th (DRC), in terms of value of the diamonds produced. In 2013 Africa produced 70.6 Mct out of a global total of 130.5 Mct or 54.1%, which was valued at US$ 8.7 billion representing 61.5% of the global value of US$ 14.1 billion.
DS201612-2306
2016
Jacob, J.Jacob, J.Using the proportion of barren samples as a proxy for minimum grade in a Diamondiferous linear beach deposit - an application of the Nachman model.Journal of South African Institute of Mining and Metallurgy, Vol. 116, Aug. pp. 731-737.Africa, NamibiaDeposit - marine placers

Abstract: Over the past 80 years, the Namibian diamondiferous marine placer has been studied extensively to develop solutions for mining and sampling challenges. The types of studies include the statistical modelling of the distributions of the stone counts per sample; investigating the relationship between geology and the grade distribution; assessing the quality potential of the entrapment of the available diamond pulse; using predetermined acceptability of barren samples (zero proportion (Zp) samples) to model distributions; optimal sample sizes; and more. During early-stage project evaluation it is more important to find out if a particular area is likely to be above a specific cut-off grade than to focus on sampling for the purpose of accurate resource estimation. Previous work using mixed Poisson and Sichel distributions to model the abundant onshore diamond data has been very successful in modelling the long-tailed nature of these linear beach deposits. The means of these distributions are, however, sensitive to extreme values. Technical and cost constraints prevent a similar scale of sample collection in an adjacent, geologically equivalent, submerged beach environment. A method not sensitive to extreme values is thus required to make early-stage assessments of the likelihood that the grade of a particular target is above a minimum cut-off grade. The Nachman model describes the functional relationship between the mean population density and proportion of barren patches ( Zp) in a patchy environment. A prerequisite for using the Nachman model is that the underlying data must be modelled using a negative binomial distribution (NBD). The case study data is from an analogous area adjacent to the exploration target and meets the NBD requirement. It is thus appropriate to apply the Nachman model. The Nachman model provides an opportunity to use the observed Zpto predict the mean grade for an area at the very early stage of an exploration project. In future, early-stage exploration data from a homogenous geological zone exhibiting characteristics of the Nachman model assumptions can thus be used to rank and target those areas that show potential to be above the minimum required grade cut-off for follow-up sampling and inclusion in the mine planning cycle.
DS201612-2307
2016
Jacob, J.Jacob, J., Prins, C.Construction of an expert opinion based virtual orebody for a Diamondiferous linear beach deposit.Journal of South African Institute of Mining and Metallurgy, Vol. 116, July pp. 629-635.Africa, NamibiaDeposit - marine placers

Abstract: During early-stage diamond exploration projects, hard data underpinning spatial continuity is often very limited. An extreme example of this is a submerged diamondiferous marine placer target area alongside a current onshore mining area in southwestern Namibia. Although an abundance of geological and grade data exists for the adjacent onshore mining area, the target area itself contains no such information. Despite this apparent abundance of data, it is extremely difficult to obtain a variogram (Prins and Jacob, 2014) for use in this study area. The use of traditional simulation techniques is further hindered by the fact that diamond entrapment within the highly gullied footwall is non-stationary. An alternative approach for creating a simulated virtual orebody (VOB) is thus required in order to enable the assessment of sampling strategies. This paper demonstrates how expert opinion is used to generate a composite probability map for diamond concentration using a greyscale hand-sketching technique. The probability map is subsequently calibrated and populated using the diamond distribution for different raised beaches obtained from analog data based on sample results adjacent to the target area. The resultant grade simulation is used to test different sample scenarios and is a first step towards determining an appropriate sampling strategy for the target area. The VOB is used to analyse and rank the efficiency of different sampling strategies for grade determination of submerged diamondiferous linear beach exploration targets.
DS201702-0217
2017
Jacob, J.Jacob, J.Overview of the Namibian diamond megaplacer: past, present and future potential.PDAC 2017, March 6, 1p. AbstractAfrica, NamibiaAlluvials
DS201709-2004
2016
Jacob, J.Jacob, J., Prins, C.Construction of an expert opinion based virtual orebody for a Diamondiferous linear beach deposit. South African Institute of Mining and Metallurgy, Vol. 116, 7, pp. 629-336.Africa, Namibiatechnology, alluvials
DS201709-2005
2016
Jacob, J.Jacob, J., Prins, C.Using the proportion of barren samples as a proxy for minimum grade in a Diamondiferous linear beach deposit - an application of the Nachman model.South African Institute of Mining and Metallurgy, Vol. 116, 8, pp. 731-737.Africa, Namibiadeposit - Orange River

Abstract: Over the past 80 years, the Namibian diamondiferous marine placer has been studied extensively to develop solutions for mining and sampling challenges. The types of studies include the statistical modelling of the distributions of the stone counts per sample; investigating the relationship between geology and the grade distribution; assessing the quality potential of the entrapment of the available diamond pulse; using predetermined acceptability of barren samples (zero proportion (Zp) samples) to model distributions; optimal sample sizes; and more. During early-stage project evaluation it is more important to find out if a particular area is likely to be above a specific cut-off grade than to focus on sampling for the purpose of accurate resource estimation. Previous work using mixed Poisson and Sichel distributions to model the abundant onshore diamond data has been very successful in modelling the long-tailed nature of these linear beach deposits. The means of these distributions are, however, sensitive to extreme values. Technical and cost constraints prevent a similar scale of sample collection in an adjacent, geologically equivalent, submerged beach environment. A method not sensitive to extreme values is thus required to make early-stage assessments of the likelihood that the grade of a particular target is above a minimum cut-off grade. The Nachman model describes the functional relationship between the mean population density and proportion of barren patches ( Zp) in a patchy environment. A prerequisite for using the Nachman model is that the underlying data must be modelled using a negative binomial distribution (NBD). The case study data is from an analogous area adjacent to the exploration target and meets the NBD requirement. It is thus appropriate to apply the Nachman model. The Nachman model provides an opportunity to use the observed Zpto predict the mean grade for an area at the very early stage of an exploration project. In future, early-stage exploration data from a homogenous geological zone exhibiting characteristics of the Nachman model assumptions can thus be used to rank and target those areas that show potential to be above the minimum required grade cut-off for follow-up sampling and inclusion in the mine planning cycle.
DS201907-1552
2019
Jacob, J.Jacob, J., Grobbelaar, G.Onshore and nearshore diamond mining on the south-western coast of Namibia: recent activities and future exploration techniques.Journal of Gemmology, Vol. 36, 6, pp. 524-533.Africa, Namibiamining
DS1994-1565
1994
Jacob, J.P.Sears, J.W., Jacob, J.P., Poage, M.A., Sims, J.L., Skinner, L.L.Mid-continent rift analog for middle Proterozoic belt basinGeological Society of America Abstracts, Vol. 26, No. 6, April p. 62. Abstract.GlobalTectonics, Midcontinent
DS1995-0863
1995
Jacob, K.H.Jacob, K.H., et al.Self organization of mineral fabricsFractal Distribution, pp. 259-268GlobalFractals, Patterned mineral fabrics
DS2003-0633
2003
Jacob, K.H.Jacob, K.H.New concepts in global tectonicsErzmetall, Vol. 56, 1, pp. 35-8.GlobalTectonics
DS1999-0329
1999
Jacob, R.J.Jacob, R.J., Bluck, B.J., Ward, J.D.Tertiary age Diamondiferous fluvial deposits of the Lower Orange RiverValley, southwestern Africa.Economic Geology, Vol. 94, No. 5, Aug. pp. 749-58.South AfricaDiamond alluvials, Orange River area
DS201712-2695
2005
Jacob, R.J.Jacob, R.J.The erosional and Cainozoic deposition history of the Lower Orange River southwestern Africa.Thesis, Phd. University of Glasgow, 178p. PdfAfrica, South Africadeposit - Lower Orange River

Abstract: A series of terraces flanking the Lower Orange River in the study area were deposited after ca. 90% of the incision had occurred, thus only the late stage incision/depositional history of this margin is able to be addressed here. Two principal suites of river terraces are distinguished by their palaeo-courses, bedrock strath levels, overall geometry and clast assemblages: an older, higher lying Proto suite and a younger Meso suite. The Proto suite represents a long, post-Eocene, through the Oligocene into the Early Miocene, phase of incision, followed by a prolonged period of aggradation where up to 90 m of fluvial, diamondiferous deposits accumulated during the Early-Middle Miocene. The Meso suite of deposits represents shorter phrases of incision and aggradation in the Pilo-Pleistocene. The Proto and Meso deposits were built in response to both base level rise and increased supply of material from tributaries draining the Great Escarpment locally, with clast assemblage and downstream fining data indicating the latter to be the more important variable. River incision into bedrock is a topic of great interest to fluvial geomorphologists, although most data are derived from active tectonic settings. The incision of a large river into a plateau surface is relatively rare, the best known example being the Colorado River in the young (6 Ma) Grand Canyon. The Orange River in the study area represents a long-lived example of this setting, with the present day dissected topography having evolved from more confined canyon-like walls following the early incision of the Orange River in the Early Tertiary. Although a long-lived incision, the modern channel is not graded in the study area, and is actively incising. The world-wide dataset of incision rates in modern rivers indicates that the Orange River could have completed its entire incision within less than a million years. The continued downcutting of this river so long after the initial incision event is indicative of the roles of intermittent, ongoing epeirogenesis and/or eustatic influences (both of which cannot be proven at this stage), tributary input from the plateau rim (Great Escarpment) or merely the long tag time involved in landscape adjustment following incision into a plateau surface.
DS201803-0466
2018
Jacob, R.J.Nakashole, A.N., Hodgson, D.M., Chapman, R.J., Morgan, D.J., Jacob, R.J.Long term controls on continental scale bedrock river terrace deposition from integrated clast and heavy mineral assemblage analysis: an example from the Lower Orange River, Namibia. ( Diamondiferous gravel terraces)Sedimentary Geology, Vol. 364, pp. 103-120.Africa, Namibiadeposit - Orange River

Abstract: Establishing relationships between the long-term landscape evolution of drainage basins and the fill of sedimentary basins benefits from analysis of bedrock river terrace deposits. These fragmented detrital archives help to constrain changes in river system character and provenance during sediment transfer from continents (source) to oceans (sink). Thick diamondiferous gravel terrace deposits along the lower Orange River, southern Namibia, provide a rare opportunity to investigate controls on the incision history of a continental-scale bedrock river. Clast assemblage and heavy mineral data from seven localities permit detailed characterisation of the lower Orange River gravel terrace deposits. Two distinct fining-upward gravel terrace deposits are recognised, primarily based on mapped stratigraphic relationships (cross-cutting relationships) and strath and terrace top elevations, and secondarily on the proportion of exotic clasts, referred to as Proto Orange River deposits and Meso Orange River deposits. The older early to middle Miocene Proto Orange River gravels are thick (up to 50 m) and characterised by a dominance of Karoo Supergroup shale and sandstone clasts, whereas the younger Plio-Pleistocene Meso Orange River gravels (6-23 m thick) are characterised by more banded iron formation clasts. Mapping of the downstepping terraces indicates that the Proto gravels were deposited by a higher sinuosity river, and are strongly discordant to the modern Orange River course, whereas the Meso deposits were deposited by a lower sinuosity river. The heavy minerals present in both units comprise magnetite, garnet, amphibole, epidote and ilmenite, with rare titanite and zircon grains. The concentration of amphibole-epidote in the heavy minerals fraction increases from the Proto to the Meso deposits. The decrease in incision depths, recorded by deposit thicknesses above strath terraces, and the differences in clast character (size and roundness) and type between the two units, are ascribed to a more powerful river system during Proto-Orange River time, rather than reworking of older deposits, changes in provenance or climatic variations. In addition, from Proto- to Meso-Orange River times there was an increase in the proportion of sediments supplied from local bedrock sources, including amphibole-epidote in the heavy mineral assemblages derived from the Namaqua Metamorphic Complex. This integrated study demonstrates that clast assemblages are not a proxy for the character of the matrix, and vice versa, because they are influenced by the interplay of different controls. Therefore, an integrated approach is needed to improve prediction of placer mineral deposits in river gravels, and their distribution in coeval deposits downstream.
DS1988-0322
1988
Jacobberger, P.A.Jacobberger, P.A.Mapping abandoned river channels in Mali through directional filtering of thematic mapper dataRemote Sensing of Environment, Vol. 26, pp. 161-170GlobalRemote Sensing, TEM.
DS2002-0848
2002
Jacobi, R.D.Kim, J., Jacobi, R.D.Boninites: characteristics and tectonic constraints, northeastern AppalachiansPhysics and Chemistry of Earth, Vol.27,pt.A,B,C,1-3,pp.109-47.AppalachiaTectonics, Boninites
DS2002-0849
2002
Jacobi, R.D.Kim, J., Jacobi, R.D.Boninites: characteristics and tectonic constraints, northeastern AppalachiansPhysics and Chemistry of the Earth, Vol. 27, pp.109-147.Quebec, Labrador, NewfoundlandTectonics, Boninites
DS202105-0781
2021
Jacobs, D.E.Pamato, M.G., Novella, D., Jacobs, D.E., Oliveira, B., Pearson, D.G., Greene, S., Alfonso, J.C., Favero, M., Stachel, T., Alvaro, M., Nestola, F.Protogenetic sulfide inclusions in diamonds date the diamond formation event using Re-Os isotopes. Victor, JerichoGeology , Vol. 49, 4, 5p. Canada, Ontario, Nunavutdiamond inclusions

Abstract: Sulfides are the most abundant inclusions in diamonds and a key tool for dating diamond formation via Re-Os isotopic analyses. The manner in which fluids invade the continental lithospheric mantle and the time scale at which they equilibrate with preexisting (protogenetic) sulfides are poorly understood yet essential factors to understanding diamond formation and the validity of isotopic ages. We investigated a suite of sulfide-bearing diamonds from two Canadian cratons to test the robustness of Re-Os in sulfide for dating diamond formation. Single-crystal X-ray diffraction (XRD) allowed determination of the original monosulfide solid-solution (Mss) composition stable in the mantle, indicating subsolidus conditions of encapsulation, and providing crystallographic evidence supporting a protogenetic origin of the inclusions. The results, coupled with a diffusion model, indicate Re-Os isotope equilibration is sufficiently fast in sulfide inclusions with typical grain size, at mantle temperatures, for the system to be reset by the diamond-forming event. This confirms that even if protogenetic, the Re-Os isochrons defined by these minerals likely reflect the ages of diamond formation, and this result highlights the power of this system to date the timing of fluid migration in mantle lithosphere.
DS1950-0180
1954
Jacobs, D.S.Jacobs, D.S.Die Geskiedenis Van die Mynwese in die O.v.s. Tussen die Jare 1854 En 1899 ,met Spesiale Verwysing Na die Diamantbedryf.M.a. Thesis, Unisa, Bloemfontein., 136P.South AfricaMining History
DS1910-0193
1911
Jacobs, E.Jacobs, E.Diamonds in British Columbia; April, 1911Engineering and Mining Journal, Vol. 91, APRIL 22ND. PP. 797-798. ALSO Canadian MiningCanada, British ColumbiaHistory
DS1860-0340
1880
Jacobs, H.Jacobs, H., Chatrian, N.Monographie du DiamantAnvers: Legros, Also: Paris: Seppelt., 211P. PP. 69-74.GlobalGemology
DS1860-0440
1884
Jacobs, H.Jacobs, H., Chatrian, N.Le Diamant (1884)Paris: Masson, G. Editeur, Libraire De L'academie De Medicin, 358P. PP. 353-374.Africa, South Africa, Global, Borneo, Brazil, India, United StatesGemology
DS1993-0730
1993
Jacobs, J.Jacobs, J., Thomas, R.J., Weber, K.Accretion and indentation tectonics at the southern edge of the Kaapvaal craton during the Kilbaran (Grenville) orogenyGeology, Vol. 21, No. 3, March pp. 203-206Zimbabwe, southern AfricaTectonics, Orogeny, Kaapval Craton
DS1994-0822
1994
Jacobs, J.Jacobs, J., Thomas, R.J.Oblique collision at about 1.1 Ga along the southern margin of the Kaapvaalcontinent, southeast AfricaGeologische Rundschau, Vol. 83, No. 2, July pp. 322-333AfricaTectonics, Kaapval craton
DS1996-0672
1996
Jacobs, J.Jacobs, J., Thomas, R.J.Pan African rejuvenation of the C. 1.1 Ga Natal metamorphic Province (SouthAfrica): K-Ar muscovite..Journal of the Geological Society of London, Vol. 153, pt. 6, pp. 971-978South Africametamorphism, Natal Province
DS1997-0548
1997
Jacobs, J.Jacobs, J., Falter, M., Jessberger, E.K.40 Ar-39 Ar thermochronological constraints on the structural evolution of the Mesoproterozoic Natal...Precambrian Research, Vol. 86, No. 1/2, Dec. 15, pp. 71-92GlobalMetamorphic province, Argon, Tectonics, structure
DS1999-0330
1999
Jacobs, J.Jacobs, J., Thomas, R.J., Henjes-Kunst, F.Age and thermal evolution of the Mesoproterozoic Cape Meredith Complex, West Falkland.Journal of Geological Society of London, Vol. 156, No. 3, May pp. 917-28.GlobalGeochronology
DS2001-0519
2001
Jacobs, J.Jacobs, J., Thomas, R.J.A titanite fission track profile across the southeastern Archean Kaapvaal CratonJournal of African Earth Sciences, Vol.33,2,pp.323-33., Vol.33,2,pp.323-33.South AfricaGeochronology, Craton - Kaapvaal
DS2001-0520
2001
Jacobs, J.Jacobs, J., Thomas, R.J.A titanite fission track profile across the southeastern Archean Kaapvaal CratonJournal of African Earth Sciences, Vol.33,2,pp.323-33., Vol.33,2,pp.323-33.South AfricaGeochronology, Craton - Kaapvaal
DS2001-0521
2001
Jacobs, J.Jacobs, J., Thomas, R.J.A titanite fission track profile across southeastern Archean Kaapvaal Craton and the Mesoproterozoic NatalJournal of African Earth Sciences, Vol.33,2,Aug.pp.323-34.South AfricaTectonism, Metamorphism
DS2003-0634
2003
Jacobs, J.Jacobs, J., Bauer, W., Fanning, C.M.New age constraints for Grenville age metamorphism in western central Dronning MaudInternational Journal of Earth Sciences, Vol. 92, No. 3, July pp. 301-315.Antarctica, RodiniaGeochronology, Orogeny, Laurentia
DS200412-0892
2003
Jacobs, J.Jacobs, J., Bauer, W., Fanning, C.M.New age constraints for Grenville age metamorphism in western central Dronning Maud Land ( east Antarctica) and implications forInternational Journal of Earth Sciences, Vol. 92, no. 3, July pp. 301-315.Antarctica, RodiniaGeochronology Orogeny, Laurentia
DS200412-2185
2003
Jacobs, J.Yoshida, M., Jacobs, J., Santosh, M., Rajesh, H.M.Role of Pan African events in the Circum East Antarctic Orogen of East Gondwana: a critical overview.Proterozoic East Gondwana: Supercontinent assembly and Breakup. Ed. Yoshida , Geological Society of London Spe, No. 206, pp. 57-76.AntarcticaPlume, tectonics
DS200612-0375
2005
Jacobs, J.Emmel, B., Jacobs, J., Kastowski, M., Graser, G.Phanerozoic upper crustal tectonothermal development of basement rocks from central Madagascar: an integrated fission track and structural study.Tectonophysics, in pressAfrica, MadagascarGeothermometry, Gondwana
DS201604-0636
2016
Jacobs, J.Thomas, R.J, Spencer, C., Bushi, A.M., Baglow, N., Gerrit de Kock, B., Hortswood, M.S.A., Hollick, L., Jacobs, J., Kajara, S., Kaminhanda, G., Key, R.M., Magana, Z., McCourt, M.W., Momburi, P., Moses, F., Mruma, A., Myamilwa, Y., Roberts, N.M.W., HamisiGeochronology of the centra Tanzania craton and its southern and eastern orogenic margins.Precambrian Research, in press available 57p.Africa, TanzaniaGeochronology

Abstract: Geological mapping and zircon U-Pb/Hf isotope data from 35 samples from the central Tanzania Craton and surrounding orogenic belts to the south and east allow a revised model of Precambrian crustal evolution of this part of East Africa. The geochronology of two studied segments of the craton shows them to be essentially the same, suggesting that they form a contiguous crustal section dominated by granitoid plutons. The oldest orthogneisses are dated at ca. 2820 Ma (Dodoma Suite) and the youngest alkaline syenite plutons at ca. 2610 Ma (Singida Suite). Plutonism was interrupted by a period of deposition of volcano-sedimentary rocks metamorphosed to greenschist facies, directly dated by a pyroclastic metavolcanic rock which gave an age of ca. 2725 Ma. This is supported by detrital zircons from psammitic metasedimentary rocks, which indicate a maximum depositional age of ca. 2740 Ma, with additional detrital sources 2820 and 2940 Ma. Thus, 200 Ma of episodic magmatism in this part of the Tanzania Craton was punctuated by a period of uplift, exhumation, erosion and clastic sedimentation/volcanism, followed by burial and renewed granitic to syenitic magmatism. In eastern Tanzania (Handeni block), in the heart of the East African Orogen, all the dated orthogneisses and charnockites (apart from those of the overthrust Neoproterozoic granulite nappes), have Neoarchaean protolith ages within a narrow range between 2710 and 2630 Ma, identical to (but more restricted than) the ages of the Singida Suite. They show evidence of Ediacaran "Pan-African" isotopic disturbance, but this is poorly defined. In contrast, granulite samples from the Wami Complex nappe were dated at ca. 605 and ca. 675 Ma, coeval with previous dates of the "Eastern Granulites" of eastern Tanzania and granulite nappes of adjacent NE Mozambique. To the south of the Tanzania Craton, samples of orthogneiss from the northern part of the Lupa area were dated at ca. 2730 Ma and clearly belong to the Tanzania Craton. However, granitoid samples from the southern part of the Lupa "block" have Palaeoproterozoic (Ubendian) intrusive ages of ca. 1920 Ma. Outcrops further south, at the northern tip of Lake Malawi, mark the SE continuation of the Ubendian belt, albeit with slightly younger ages of igneous rocks (ca. 1870-1900 Ma) which provide a link with the Ponte Messuli Complex, along strike to the SE in northern Mozambique. In SW Tanzania, rocks from the Mgazini area gave Ubendian protolith ages of ca. 1980-1800 Ma, but these rocks underwent Late Mesoproterozoic high-grade metamorphism between 1015 and 1040 Ma. One granitoid gave a crystallisation age of ca. 1080 Ma correlating with known Mesoproterozoic crust to the east in SE Tanzania and NE Mozambique. However, while the crust in the Mgazini area was clearly one of original Ubendian age, reworked and intruded by granitoids at ca. 1 Ga, the crust of SE Tanzania is a mixed Mesoproterozoic terrane and a continuation from NE Mozambique. Hence the Mgazini area lies at the edge of the Ubendian belt which was re-worked during the Mesoproterozoic orogen (South Irumide belt), providing a further constraint on the distribution of ca. 1 Ga crust in SE Africa. Hf data from near-concordant analyses of detrital zircons from a sample from the Tanzania Craton lie along a Pb-loss trajectory (Lu/Hf = 0), extending back to ?3.9 Ga. This probably represents the initial depleted mantle extraction event of the cratonic core. Furthermore, the Hf data from all igneous samples, regardless of age, from the entire study area (including the Neoproterozoic granulite nappes) show a shallow evolution trend (Lu/Hf = 0.028) extending back to the same mantle extraction age. This implies the entire Tanzanian crust sampled in this study represents over 3.5 billion years of crustal reworking from a single crustal reservoir and that the innermost core of the Tanzanian Craton that was subsequently reworked was composed of a very depleted, mafic source with a very high Lu/Hf ratio. Our study helps to define the architecture of the Tanzanian Craton and its evolution from a single age-source in the early Eoarchaean.
DS201710-2219
2017
Jacobs, J.Cerantola, V., Bykova, E., Kupenko, I., Merlini, M., Ismailova, L., McCammon, C., Bykov, M., Chumakov, A.I., Petitgirard, S., Kantor, I., Svityk, V., Jacobs, J., Hanfland, M., Mezouar, M., Prescher, C., Ruffer, R., Prakapenka, V.B., Duvbovinsky, L.How iron carbonates help form diamonds.Nature Communications, July 18 #15960Mantlecarbonate inclusions
DS1991-0778
1991
Jacobs, J.A.Jacobs, J.A.The deep interior of the earthChapman and Hall, 160p. approx. $ 30.00 United StatesGlobalBook -ad, Deep interior of the earth
DS1992-0765
1992
Jacobs, J.A.Jacobs, J.A.The earth's core in a nutshellNature, Vol. 356, No. 6367, March 26, p. 286-287MantleCore, Geophysics, seismics
DS1995-0864
1995
Jacobs, J.A.Jacobs, J.A.The earth's inner core and the geodynamo: determining their roles in theearth's history.Eos, Vol. 76, No. 25, June 20, p. 249, 253.MantleGeomagnetisM., Boundary conditions
DS1997-0549
1997
Jacobs, J.A.Jacobs, J.A.The earth's inner coreTerra Nova, Vol. 9, pp. 140-143.MantleGeodynamics, anisotropy, Inner core
DS1940-0116
1946
Jacobs, J.F.Jacobs, J.F.Diamante. #1Bloemfontein: Nas. Pers. Kennis Vir Almal, SER. No. 39. PP. 9-87.South AfricaHistory, Diamond
DS2003-0929
2003
Jacobs, P.Mees, F., Swennen, R., Van Geet, M., Jacobs, P.Applications of X ray computed tomography in the GeosciencesGeological Society of London Publ., http://bookshop.geolsoc.org.uk, SP 215, 256p. approx. $110.USGlobalBook - tomography - general interest
DS200412-1288
2003
Jacobs, P.Mees, F., Swennen, R., Van Geet, M., Jacobs, P.Applications of X ray computed tomography in the Geosciences.Geological Society of London , SP 215, 256p. approx. $110.USTechnologyBook - tomography
DS200812-0560
2008
Jacobs, P.Kervyn, M., Ernst, G.G., Harris, A.J.L., Belton, F., Mbede, E., Jacobs, P.Thermal remote sensing of the low intensity carbonatite volcanism of Oldoinyo Lengai, Tanzania,International Journal of Remote Sensing, Vol. 29, 22, pp. 6467-6499.Africa, TanzaniaCarbonatite
DS1992-0766
1992
Jacobs, S.S.Jacobs, S.S.Is the Antarctic ice sheet growing?Nature, Vol. 360, November 5, pp. 29-33AntarcticaGeomorphology, Review article on glacial activity
DS200612-0633
2006
Jacobs, T.Jacobs, T.Any diamonds in the diagnostic coal?Nature Biotechnology, Vol. 24, 8, p. 930. (1p).TechnologyCarbon - coal
DS201511-1851
2015
Jacobsen, B.Kaminsky, F., Matzel, J., Jacobsen, B., Hutcheon, I., Wirth, R.Isotopic fractionation of oxygen and carbin in decomposed lower-mantle inclusions in diamond. Rio Soriso Mineralogy and Petrology, DOI 10. 1007/s00710-015-0401-7South America, Brazil, Mato GrossoJuina area

Abstract: Two carbonatitic mineral assemblages, calcite + wollastonite and calcite + monticellite, which are encapsulated in two diamond grains from the Rio Soriso basin in the Juina area, Mato Grosso State, Brazil, were studied utilizing the NanoSIMS technique. The assemblages were formed as the result of the decomposition of the lower-mantle assemblage calcite + CaSi-perovskite + volatile during the course of the diamond ascent under pressure conditions from 15 to less than 0.8 GPa. The oxygen and carbon isotopic compositions of the studied minerals are inhomogeneous. They fractionated during the process of the decomposition of primary minerals to very varying values: ?18O from ?3.3 to +15.4?‰SMOW and ?13C from ?2.8 to +9.3?VPDB. These values significantly extend the mantle values for these elements in both isotopically-light and isotopically-heavy areas.
DS201602-0235
2015
Jacobsen, B.H.Schiffer, C., Stephenson, R.A., Petersen, K.D., Nielsen, S.B., Jacobsen, B.H., Balling, N., Macdonald, D.I.M.A sub crustal piercing point for North Atlantic reconstructions and tectonic implications.Geology, Vol. 43, 12, pp. 1087-1090.Europe, GreenlandPlate Tectonics

Abstract: Plate tectonic reconstructions are usually constrained by the correlation of lineaments of surface geology and crustal structures. This procedure is, however, largely dependent on and complicated by assumptions on crustal structure and thinning and the identification of the continent-ocean transition. We identify two geophysically and geometrically similar upper mantle structures in the North Atlantic and suggest that these represent remnants of the same Caledonian collision event. The identification of this structural lineament provides a sub-crustal piercing point and hence a novel opportunity to tie plate tectonic reconstructions. Further, this structure coincides with the location of some major tectonic events of the North Atlantic post-orogenic evolution such as the occurrence of the Iceland Melt Anomaly and the separation of the Jan Mayen microcontinent. We suggest that this inherited orogenic structure played a major role in the control of North Atlantic tectonic processes.
DS201605-0850
2016
Jacobsen, S.Jacobsen, S.Earth's deep mantle water cycle: what diamond inclusions might be telling us.DCO Edmonton Diamond Workshop, June 8-10MantleDiamond Inclusions
DS202009-1631
2020
Jacobsen, S.Hyung, E., Jacobsen, S.The 142Nd/144 Nd variations in mantle derived rocks provide constraints on the stirring rate of the mantle from the Hadean to the present.Proceedings of the National Academy of Sciences, Voll. 176, no. 26, 14738-44. pdfMantleplate tectonics

Abstract: Early silicate differentiation events for the terrestrial planets can be traced with the short-lived 146Sm-142Nd system (?100-My half-life). Resulting early Earth-produced 142Nd/144Nd variations are an excellent tracer of the rate of mantle mixing and thus a potential tracer of plate tectonics through time. Evidence for early silicate differentiation in the Hadean (4.6 to 4.0 Ga) has been provided by 142Nd/144Nd measurements of rocks that show both higher and lower (±20 ppm) values than the present-day mantle, demonstrating major silicate Earth differentiation within the first 100 My of solar system formation. We have obtained an external 2? uncertainty at 1.7 ppm for 142Nd/144Nd measurements to constrain its homogeneity/heterogeneity in the mantle for the last 2 Ga. We report that most modern-day mid-ocean ridge basalt and ocean island basalt samples as well as continental crustal rocks going back to 2 Ga are within 1.7 ppm of the average Earth 142Nd/144Nd value. Considering mafic and ultramafic compositions, we use a mantle-mixing model to show that this trend is consistent with a mantle stirring time of about 400 My since the early Hadean. Such a fast mantle stirring rate supports the notion that Earth’s thermal and chemical evolution is likely to have been largely regulated by plate tectonics for most of its history. Some young rocks have 142Nd/144Nd signatures marginally resolved (?3 ppm), suggesting that the entire mantle is not equally well homogenized and that some silicate mantle signatures from an early differentiated mantle (>4.1 Ga ago) are preserved in the modern mantle.
DS1984-0374
1984
Jacobsen, S.B.Jacobsen, S.B., Quick, J.E., Wasserburg, G.J.A Neodymium and Strontium Isotopic Study of the Trinity Peridotite- implic Ations for Mantle Evolution.Earth and Planetary Science Letters, Vol. 68, No. 3, JUNE PP. 361-378.United States, CaliforniaGeochronology
DS1992-0670
1992
Jacobsen, S.B.Harper, C.L.Jr., Jacobsen, S.B.Evidence from coupled 147 Sm-143 neodymium and 146 Sm-142 neodymium systematics for very early (4.5-Gyr) differentiation of the earth's mantleNature, Vol. 360, No. 6406, December 24/31, pp. 728-732GlobalGeochronology, Mantle
DS1992-0767
1992
Jacobsen, S.B.Jacobsen, S.B., Harper, C.J.Isotopic modeling of crust and mantle evolutionV.m. Goldschmidt Conference Program And Abstracts, Held May 8-10th. Reston, p. A 54. abstractMantleGeochronology, Crust
DS1996-0601
1996
Jacobsen, S.B.Harper, C.L., Jacobsen, S.B.Evidence for 182 Hafnium in the Early Solar system and constraints on the time scale of terrestrial accretion and core formation.Geochimica Et Cosmochimica Acta, Vol. 60, No. 7, pp. 1131-53.MantleDensity - core
DS1998-0678
1998
Jacobsen, S.B.Jacobsen, S.B., Yin, Q.Models for the accretion and early differentiation of the EarthMineralogical Magazine, Goldschmidt abstract, Vol. 62A, p. 694-5.MantleAccretion
DS2003-0635
2003
Jacobsen, S.B.Jacobsen, S.B.How old is planet Earth?Science, No. 5625, June 6, p. 1513.EarthGeochronology
DS2003-0636
2003
Jacobsen, S.B.Jacobsen, S.B.Geochemistry - lost terrains of early EarthNature, No. 6926, Feb. 27, pp. 901-2.MantleGeochemistry
DS200412-0893
2003
Jacobsen, S.B.Jacobsen, S.B.How old is planet Earth?Science, No. 5625, June 6, p. 1513.TechnologyGeochronology
DS200412-1457
2004
Jacobsen, S.B.O'Connell, R.J., Kellogg, J.B., Jacobsen, S.B.Heterogeneity and geochemical reservoirs in the mantle.Geochimica et Cosmochimica Acta, 13th Goldschmidt Conference held Copenhagen Denmark, Vol. 68, 11 Supp. July, ABSTRACT p.A558.MantleGeochemistry
DS200512-0472
2005
Jacobsen, S.B.Jacobsen, S.B.The Hf-W isotopic system and the origin of the Earth and Moon.Annual Review of Earth and Planetary Sciences, Vol. 33, May pp. 531-570.Review - geochronology
DS200512-0927
2005
Jacobsen, S.B.Saha, A., Basu, A.R., Jacobsen, S.B., Poreda, R.J., Yin, Q.Z., Yogodzinski, G.M.Slab devolatization and Os and Pb mobility in the mantle wedge of the Kamchatka arc.Earth and Planetary Science Letters, Advanced in press,Russia, KamchatkaGeochronology, slab
DS200912-0331
2009
Jacobsen, S.B.Jacobsen, S.B.The growth of the continental crust: isotopic constraints on timing and rates.Goldschmidt Conference 2009, p. A580 Abstract.MantleGeochronology
DS2003-1300
2003
Jacobsen, S.D.Smyth, J.R., Holl, C.M., Frost, D.J., Jacobsen, S.D., Langenhorst, F.Structural systematics of hydrous ring woodite and water in Earth's interiorAmerican Mineralogist, Vol. 88, 10, Oct. pp. 1402-7.MantleMineralogy
DS200412-0219
2004
Jacobsen, S.D.Bromiley, G.D., Keppler, H., McCammon, C., Bromiley, F.A., Jacobsen, S.D.Hydrogen solubility and speciation in natural gem quality chromian diopside.American Mineralogist, Vol. 89, 6, pp. 941-949.TechnologyPetrology, experimental ( not specific to diamonds)
DS200412-1863
2003
Jacobsen, S.D.Smyth, J.R., Holl, C.M., Frost, D.J., Jacobsen, S.D., Langenhorst, F., McCammon, C.A.Structural systematics of hydrous ring woodite and water in Earth's interior.American Mineralogist, Vol. 88, 10, Oct. pp. 1402-7.MantleMineralogy
DS200512-0638
2005
Jacobsen, S.D.Lin, J.F., Struzhkin, V.V., Jacobsen, S.D., Hu, M.Y., Chow, P., Kung, J., Liu, H., Mao, H., Hemley, R.J.Spin transition of iron in magnesiowustite in the Earth's lower mantle.Nature, No. 7049, July 21, pp. 377-380.MantleMineralogy
DS200612-0327
2006
Jacobsen, S.D.Demouchy, S., Jacobsen, S.D., Gaillard, F., Stern, C.R.Rapid magma ascent recorded by water diffusion profiles in mantle olivine.Geology, Vol. 34, 6, June pp. 429-432.Mantle, South America, ChileMagmatism, xenoliths - not specific to diamonds
DS200712-0476
2007
Jacobsen, S.D.Jacobsen, S.D., Van der Lee, S., Smyth, J.R., Holl, C.M.Detecting hydration in the Earth's mantle.Frontiers in Mineral Sciences 2007, Joint Meeting of Mineralogical societies Held June 26-28, Cambridge, Abstract Volume p.187-188.MantleWater
DS200712-0477
2007
Jacobsen, S.D.Jacobsen, S.D., Van der Lee, S., Smyth, J.R., Holl, C.M.Detecting hydration in the Earth's mantle.Frontiers in Mineral Sciences 2007, Joint Meeting of Mineralogical societies Held June 26-28, Cambridge, Abstract Volume p.187-188.MantleWater
DS201212-0727
2012
Jacobsen, S.D.Thomas, S-M., Bina, C.R., Jacobsen, S.D., Goncharov, A.F.Radiative heat transfer in a hydrous mantle transition zone.Earth and Planetary Science Letters, Vol. 357-358, pp. 130-138.MantleGothermometry
DS201312-0147
2013
Jacobsen, S.D.Chang, Y-Y., Jacobsen, S.D., Lin, J-F., Bina, C.R., Thomas, S-M., Wu, J., Shen, G., Xiao, Y., Chow, P., Frost, D.J., McCammon, C.A., Dera, P.Spin transition off F23+ in Al bearing phase D: an alternative explanation for small scale seismic scatterers in the mid-lower mantle.Earth and Planetary Science Letters, Vol. 382, pp. 1-9.MantleGeophysics, seismics
DS201412-0779
2014
Jacobsen, S.D.Schmandt, B., Jacobsen, S.D., Becker, T.W., Liu, Z., Dueker, K.G.Dehydration melting at the top of the lower mantle.Science, Vol. 344, 6189, June 13, pp. 1265-68.MantleWater in transition zone
DS201603-0368
2015
Jacobsen, S.D.Chang, Y-Y., Jacobsen, S.D., Bina, C.R., Thomas, S-M., Smyth, J.R., Frost, D.J., Boffa Ballaran, T., McCammon, C.A., Hauri, E.H., Inoue, T., Yurimoto, H., Meng, Y., Dera, P.Comparative compressibility of hydrous wadsleyite and ringwoodite: effect of H2O and implications for detecting water in the transition zone.Journal of Geophysical Research,, Vol. 120, 12, pp. 8259-8280.MantleRingwoodite

Abstract: Review of recent mineral physics literature shows consistent trends for the influence of Fe and H2O on the bulk modulus (K0) of wadsleyite and ringwoodite, the major phases of Earth's mantle transition zone (410-660?km). However, there is little consensus on the first pressure derivative, K0??=?(dK/dP)P=0, which ranges from about 4 to >5 across experimental studies and compositions. Here we demonstrate the importance of K0? in evaluating the bulk sound velocity of the transition zone in terms of water content and provide new constraints on the effect of H2O on K0? for wadsleyite and ringwoodite by conducting a comparative compressibility study. In the experiment, multiple crystals of hydrous Fo90 wadsleyite containing 2.0 and 0.25?wt?% H2O were loaded into the same diamond anvil cell, along with hydrous ringwoodite containing 1.4?wt?% H2O. By measuring their pressure-volume evolution simultaneously up to 32?GPa, we constrain the difference in K0? independent of the pressure scale, finding that H2O has no effect on K0?, whereas the effect of H2O on K0 is significant. The fitted K0? values of hydrous wadsleyite (0.25 and 2.0?wt?% H2O) and hydrous ringwoodite (1.4?wt?% H2O) examined in this study were found to be identical within uncertainty, with K0? ~3.7(2). New secondary-ion mass spectrometry measurements of the H2O content of these and previously investigated wadsleyite samples shows the bulk modulus of wadsleyite is reduced by 7.0(5)?GPa/wt?% H2O, independent of Fe content for upper mantle compositions. Because K0? is unaffected by H2O, the reduction of bulk sound velocity in very hydrous regions of transition zone is expected to be on the order of 1.6%, which is potentially detectible in high-resolution, regional seismology studies.
DS201608-1430
2016
Jacobsen, S.D.Palot, M., Jacobsen, S.D., Townsend, J.P., Nestols, F., Marquardt, K., Harris, J.W., Stachel, T., McCammon, C.A., Pearson, D.G.Evidence for H2O bearing fluids in the lower mantle from diamond inclusion.Lithos, in press available 27p.South America, BrazilSao Luis

Abstract: In this study, we report the first direct evidence for water-bearing fluids in the uppermost lower mantle from natural ferropericlase crystal contained within a diamond from São Luíz, Brazil. The ferropericlase exhibits exsolution of magnesioferrite, which places the origin of this assemblage in the uppermost part of the lower mantle. The presence of brucite-Mg(OH)2 precipitates in the ferropericlase crystal reflects the later-stage quenching of H2O-bearing fluid likely in the transition zone, which has been trapped during the inclusion process in the lower mantle. Dehydration melting may be one of the key processes involved in transporting water across the boundary between the upper and lower mantle.
DS201611-2149
2016
Jacobsen, S.D.Zhang, L., Smyth, J.R., Allaz, J., Kawazoe, T., Jacobsen, S.D., Jin, Z.Transition metals in the transition zone: crystal chemistry of minor element substitution in wadsleyite.American Mineralogist, Vol. 101, pp. 2322-2330.TechnologyWadsleyite

Abstract: As the most abundant solid phase at depths of 410-525 km, wadsleyite constitutes a large geochemical reservoir in the Earth. To better understand the implications of minor element substitution and cation ordering in wadsleyite, we have synthesized wadsleyites coexisting with pyroxenes with 2-3 wt% of either TiO2, Cr2O3, V2O3, CoO, NiO, or ZnO under hydrous conditions in separate experiments at 1300 °C and 15 GPa. We have refined the crystal structures of these wadsleyites by single-crystal X-ray diffraction, analyzed the compositions by electron microprobe, and estimated M3 vacancy concentration from b/a cell-parameter ratios. According to the crystal structure refinements, Cr and V show strong preferences for M3 over M1 and M2 sites and significant substitution up to 2.9 at% at the tetrahedral site (T site). Ni, Co, and Zn show site preferences similar to those of Fe with M1? M3 > M2 > T. The avoidance of Ni, Co, and Fe for the M2 site in both wadsleyite and olivine appears to be partially controlled by crystal field stabilization energy (CFSE). The estimated CFSE values of Ni2+, Co2+, and Zn2+ at three distinct octahedral sites show a positive correlation with octahedral occupancy ratios [M2/(M1+M3)]. Ti substitutes primarily into the M3 octahedron, rather than M1, M2, or T sites. Ti, Cr, and V each have greater solubility in wadsleyite than in olivine. Therefore these transition metal cations may be enriched in a melt or an accessory phase if hydrous melting occurs on upward convection across the wadsleyite-olivine boundary and may be useful as indicators of high-pressure origin.
DS201807-1540
2018
Jacobsen, S.D.Zhang, L., Smyth, J.R., Kawazoe, T., Jacobsen, S.D., Qin, S.Transition metals in the transition zone: partitioning of Ni, Co, and Zn between olivine, wadsleyite, ringwoodite, and clineoenstatite.Contributions to Mineralogy and Petrology, 10.1007/ s00410-018-1478-x 10p.Mantlemelting

Abstract: Ni, Co, and Zn are widely distributed in the Earth’s mantle as significant minor elements that may offer insights into the chemistry of melting in the mantle. To better understand the distribution of Ni2+, Co2+, and Zn2+ in the most abundant silicate phases in the transition zone and the upper mantle, we have analyzed the crystal chemistry of wadsleyite (Mg2SiO4), ringwoodite (Mg2SiO4), forsterite (Mg2SiO4), and clinoenstatite (Mg2Si2O6) synthesized at 12-20 GPa and 1200-1400 °C with 1.5-3 wt% of either NiO, CoO, or ZnO in starting materials. Single-crystal X-ray diffraction analyses demonstrate that significant amounts of Ni, Co, and Zn are incorporated in octahedral sites in wadsleyite (up to 7.1 at%), ringwoodite (up to 11.3 at%), olivine (up to 2.0 at%), and clinoenstatite (up to 3.2 at%). Crystal structure refinements indicate that crystal field stabilization energy (CFSE) controls both cation ordering and transition metal partitioning in coexisting minerals. According to electron microprobe analyses, Ni and Co partition preferentially into forsterite and wadsleyite relative to coexisting clinoenstatite. Ni strongly prefers ringwoodite over coexisting wadsleyite with DRw/WdNi?=?4.13. Due to decreasing metal-oxygen distances with rising pressure, crystal field effect on distribution of divalent metal ions in magnesium silicates is more critical in the transition zone relative to the upper mantle. Analyses of Ni partitioning between the major upper-mantle phases implies that Ni-rich olivine in ultramafic rocks can be indicative of near-primary magmas.
DS201907-1524
2019
Jacobsen, S.D.Anzolini, C., Wang, F., Harris, G.A., Locock, A.J., Zhang, D., Nestola, F., Peruzzo, L., Jacobsen, S.D., Pearson, D.G.Nixonite, Na2Ti6O13, a new mineral from a metasomatized mantle garnet pyroxenite from the western Rae Craton, Darby kimberlite field, Canada.American Mineralogist, in press available 26p.Canada, Nunavutdeposit - Darby

Abstract: Nixonite (IMA 2018-133), ideally Na2Ti6O13, is a new mineral found within a heavily-metasomatized pyroxenite xenolith from the Darby kimberlite field, beneath the west central Rae Craton, Canada. It occurs as microcrystalline aggregates, 15 to 40 ?m in length. Nixonite is isostructural with jeppeite, K2Ti6O13, with a structure consisting of edge- and corner-shared titanium-centered octahedra that enclose alkali-metal ions. The Mohs hardness is estimated to be between 5 and 6 by comparison to jeppeite and the calculated density is 3.51(1) g/cm3. Electron microprobe wavelength-dispersive spectroscopic analysis (average of 6 points) yielded: Na2O 6.87, K2O 5.67 CaO 0.57, TiO2 84.99, V2O3 0.31, Cr2O3 0.04, MnO 0.01, Fe2O3 0.26, SrO 0.07, total 98.79 wt%. The empirical formula, based on 13 O atoms, is: (Na1.24K0.67Ca0.06)?1.97(Ti5.96V0.023Fe0.018)?6.00O13 with minor amounts of Cr and Mn. Nixonite is monoclinic, space group C2/m, with unit-cell parameters a = 15.3632(26) Å, b = 3.7782(7) Å, c = 9.1266(15) Å, ? = 99.35(15)º and V = 522.72(1) Å3, Z = 2. Based on the average of seven integrated multi-grain diffraction images, the strongest diffraction lines are [dobs in Å (I in %) (h k l)]: 3.02 (100) (3 1 0) , 3.66 (75) (1 1 0), 7.57 (73) (2 0 0), 6.31 (68) (2 0 -1), 2.96 (63) (3 1 -1), 2.96 (63) (2 0 -3) and 2.71 (62) (4 0 2). The five main Raman peaks of nixonite, in order of decreasing intensity, are at: 863, 280, 664, 135 and 113 cm-1. Nixonite is named after Peter H. Nixon, a renowned scientist in the field of kimberlites and mantle xenoliths. Nixonite occurs within a pyroxenite xenolith in a kimberlite, in association with rutile, priderite, perovskite, freudenbergite and ilmenite. This complex Na-K-Ti rich metasomatic mineral assemblage may have been produced by a fractionated Na-rich kimberlitic melt that infiltrated a mantle-derived garnet pyroxenite and reacted with rutile during kimberlite crystallization.
DS201908-1825
2019
Jacobsen, S.D.Wenz, M.D., Jacobsen, S.D., Zhang, D., Regier, M., Bausch, H.J., Dera, P.K., Rivers, M., Eng, P., Shirey, S.B., Pearson, D.G.Fast identification of mineral inclusions in diamond at GSECARS using synchrotron X-ray microtomography, radiography and diffraction.Journal of Synchrotron Radiation, Vol. 26, doi.org/10.1107 /S1600577519006854 6p. PdfMantlediamond inclusions

Abstract: Mineral inclusions in natural diamond are widely studied for the insight that they provide into the geochemistry and dynamics of the Earth's interior. A major challenge in achieving thorough yet high rates of analysis of mineral inclusions in diamond derives from the micrometre-scale of most inclusions, often requiring synchrotron radiation sources for diffraction. Centering microinclusions for diffraction with a highly focused synchrotron beam cannot be achieved optically because of the very high index of refraction of diamond. A fast, high-throughput method for identification of micromineral inclusions in diamond has been developed at the GeoSoilEnviro Center for Advanced Radiation Sources (GSECARS), Advanced Photon Source, Argonne National Laboratory, USA. Diamonds and their inclusions are imaged using synchrotron 3D computed X-ray microtomography on beamline 13-BM-D of GSECARS. The location of every inclusion is then pinpointed onto the coordinate system of the six-circle goniometer of the single-crystal diffractometer on beamline 13-BM-C. Because the bending magnet branch 13-BM is divided and delivered into 13-BM-C and 13-BM-D stations simultaneously, numerous diamonds can be examined during coordinated runs. The fast, high-throughput capability of the methodology is demonstrated by collecting 3D diffraction data on 53 diamond inclusions from Juína, Brazil, within a total of about 72 h of beam time.
DS201910-2285
2019
Jacobsen, S.D.Meyer, N.A., Wenz, M.D., Walsh, J.P.S., Jacobsen, S.D., Locock, A.J., Harris, J.W.Goldschmidtite, ( K,REE,Sr) (Nb,Cr)03: a new perovskite supergroup mineral found in diamond from Koffiefontein, South Africa.American Mineralogist, Vol. 104, pp. 1345-1350.Africa, South Africadeposit - Koffiefontein

Abstract: Goldschmidtite is a new perovskite-group mineral (IMA No. 2018-034) with the ideal formula (K,REE,Sr)(Nb,Cr)O3. A single grain of goldschmidtite with a maximum dimension of ?100 ?m was found as an inclusion in a diamond from the Koffiefontein pipe in South Africa. In addition to the dark green and opaque goldschmidtite, the diamond contained a Cr-rich augite (websteritic paragenesis) and an intergrowth of chromite, Mg-silicate, and unidentified K-Sr-REE-Nb-oxide. Geothermobarometry of the augite indicates that the depth of formation was ?170 km. The chemical composition of gold-schmidtite determined by electron microprobe analysis (n = 11, WDS, wt%) is: Nb2O5 44.82, TiO2 0.44, ThO2 0.10, Al2O3 0.35, Cr2O3 7.07, La2O3 11.85, Ce2O3 6.18, Fe2O3 1.96, MgO 0.70, CaO 0.04, SrO 6.67, BaO 6.82, K2O 11.53, total 98.53. The empirical formula (expressed to two decimal places) is (K0.50La0.15Sr0.13Ba0.09Ce0.08)?0.95(Nb0.70Cr0.19Fe0.05Al0.01Mg0.04Ti0.01)?1.00O3. Goldschmidtite is cubic, space group Pm3m, with unit-cell parameters: a = 3.9876(1) Å, V = 63.404(6) Å3, Z = 1, resulting in a calculated density of 5.32(3) g/cm3. Goldschmidtite is the K-analog of isolueshite, (Na,La)NbO3. Raman spectra of goldschmidtite exhibit many second-order broad bands at 100 to 700 cm-1 as well as a pronounced peak at 815 cm-1, which is possibly a result of local ordering of Nb and Cr at the B site. The name goldschmidtite is in honor of the eminent geochemist Victor Moritz Goldschmidt (1888-1947), who formalized perovskite crystal chemistry and identified KNbO3 as a perovskite-structured compound.
DS201912-2825
2020
Jacobsen, S.D.Shirey, S.B., Smit, K.V., Pearson, D.G., Walter, M.J., Aulbach, S., Brenker, F.E., Bureau, H., Burnham, A.D., Cartigny, P., Chacko, T., Frost, D.J., Hauri, E.H., Jacob, D.E., Jacobsen, S.D., Kohn, S.C., Luth, R.W., Mikhail, S., Navon, O., Nestola, F., NimDiamonds and the mantle geodynamics of carbon: deep mantle carbon and evolution from the diamond record.IN: Deep carbon: past to present, Orcutt, Daniel, Dasgupta eds., pp. 89-128.Mantlegeodynamics

Abstract: The science of studying diamond inclusions for understanding Earth history has developed significantly over the past decades, with new instrumentation and techniques applied to diamond sample archives revealing the stories contained within diamond inclusions. This chapter reviews what diamonds can tell us about the deep carbon cycle over the course of Earth’s history. It reviews how the geochemistry of diamonds and their inclusions inform us about the deep carbon cycle, the origin of the diamonds in Earth’s mantle, and the evolution of diamonds through time.
DS202001-0039
2020
Jacobsen, S.D.Shirey, S.B., Smit, K.V., Pearson, D.G., Walter, M.J., Aulbach, S., Brenker, F.E., Bureau, H., Burnham, A.D., Cartigny, P., Chacko, T., Frost, D.J., Hauri, E.H., Jacob, D.E., Jacobsen, S.D., Kohn, S.C., Luth, R.W., Mikhail, S., Navon, O., Nestola, F., NimDiamonds and mantle geodynamics of carbon: IN: Deep Carbon: past to present. Editors Orcutt, Danielle, Dasgupta, pp. 89-128.Mantlegeodynamics

Abstract: The science of studying diamond inclusions for understanding Earth history has developed significantly over the past decades, with new instrumentation and techniques applied to diamond sample archives revealing the stories contained within diamond inclusions. This chapter reviews what diamonds can tell us about the deep carbon cycle over the course of Earth’s history. It reviews how the geochemistry of diamonds and their inclusions inform us about the deep carbon cycle, the origin of the diamonds in Earth’s mantle, and the evolution of diamonds through time.
DS202107-1128
2019
Jacobsen, S.D.Shirey, S.B., Smit, K.V., Pearson, D.G., Walter, M.J., Aulbach, S., Brenker, F.E., Bureau, H., Burnham, A.D., Cartigny, P., Chacko, T., Frost, D.J., Hauri, E.H., Jacob, D.E., Jacobsen, S.D., Kohn, S.C., Luth, R.W., Mikhail, S., Navon, O.. Nestola, F., NimDiamonds and mantle geodynamics of carbon.Deep Carbon - Cambridge University Press , Cambridge.org 40p. PdfMantlecarbon
DS200412-0894
2004
Jacobsen, S.R.Jacobsen, S.R., Kellogg, J.B., O'Connell, R.J.Isotopic heterogeneity in the mantle: in search of the final explanation.Geochimica et Cosmochimica Acta, 13th Goldschmidt Conference held Copenhagen Denmark, Vol. 68, 11 Supp. July, ABSTRACT p.A552.MantleGeochronology
DS2002-1109
2002
Jacobshagen, V.Muller, J.P., Kley, J., Jacobshagen, V.Structure and Cenozoic kinematics of the Eastern Cordillera, southern BoliviaTectonics, Vol. 21, No. 5, 10.1029/2001TC001340.BoliviaTectonics - structure
DS2001-0522
2001
Jacobson, C.E.Jacobson, C.E.Using Auto CAD for descriptive geometry exercisesComputers and Geosciences, Vol. 27, No. 1, Feb. pp. 9-15.GlobalComputer - AutoCAD.
DS1940-0182
1948
Jacobson, D.Jacobson, D.Maize Turns to GoldCape Town: Harold Timmins, South AfricaKimberlite, Kimberley, Janlib, Gold
DS1986-0393
1986
Jacobson, D.Jacobson, D.The price of diamonds. ( reprint of 1957 novel)Johannesburg, distributed by Frank Thorold Africana Bookseller, 256p. approx. $ 12.95R.South AfricaHistory
DS1995-1049
1995
Jacobson, E.Lamorey, G., Jacobson, E.Estimation of semivariogram parameters and evaluation of the effects ofdat a sparcityMathematical Geology, Vol. 27, No. 3, pp. 327-358GlobalGeostatistics, Jackknife kriging
DS202102-0185
2020
Jacobson, N.S.Fegley, B., Lodders, K., Jacobson, N.S.Volatile element chemistry during accretion of the Earth.Geochemistry, Vol. 80, doi.org/10.1016/ j.chemer. 2019.125594 40p. PdfMantlegeochemistry

Abstract: We review some issues relevant to volatile element chemistry during accretion of the Earth with an emphasis on historical development of ideas during the past century and on issues we think are important. These ideas and issues include the following: (1) whether or not the Earth accreted hot and the geochemical evidence for high temperatures during its formation, (2) some chemical consequences of the Earth’s formation before dissipation of solar nebular gas, (3) the building blocks of the Earth, (4) the composition of the Earth and its lithophile volatility trend, (5) chemistry of silicate vapor and steam atmospheres during Earth’s formation, (6) vapor - melt partitioning and possible loss of volatile elements, (7) insights from hot rocky extrasolar planets. We include tabulated chemical kinetic data for high-temperature elementary reactions in silicate vapor and steam atmospheres. We finish with a summary of the known and unknown issues along with suggestions for future work.
DS1994-0264
1994
Jacobson, R.S.Carlson, R.L., Jacobson, R.S.Comment on Upper Crustal structure as a function of plate age... by Houtzand EwingJournal of Geophysical Research, Vol. 99, No. B 2, February 10, pp. 3135-3138MantleStructure
DS201604-0600
2016
Jacobson, S.De Vries, J., Nimmo, F., Melosh, H., Jacobson, S., Morbidelli, A., Rubie, D.Impact induced melting during accretion of the Earth.Progress in Earth and Planetary Science, Vol. 3, 7p.MantleMelting

Abstract: Because of the high energies involved, giant impacts that occur during planetary accretion cause large degrees of melting. The depth of melting in the target body after each collision determines the pressure and temperature conditions of metal-silicate equilibration and thus geochemical fractionation that results from core-mantle differentiation. The accretional collisions involved in forming the terrestrial planets of the inner Solar System have been calculated by previous studies using N-body accretion simulations. Here we use the output from such simulations to determine the volumes of melt produced and thus the pressure and temperature conditions of metal-silicate equilibration, after each impact, as Earth-like planets accrete. For these calculations a parameterised melting model is used that takes impact velocity, impact angle and the respective masses of the impacting bodies into account. The evolution of metal-silicate equilibration pressures (as defined by evolving magma ocean depths) during Earth’s accretion depends strongly on the lifetime of impact-generated magma oceans compared to the time interval between large impacts. In addition, such results depend on starting parameters in the N-body simulations, such as the number and initial mass of embryos. Thus, there is the potential for combining the results, such as those presented here, with multistage core formation models to better constrain the accretional history of the Earth.
DS201603-0433
2016
Jacobson, S.A.Young, E.D., Kohl, I.E., Warren, P.H., Rubie, D.C., Jacobson, S.A., Morbidelli, A.Oxygen isotopic evidence for vigorous mixing during the moon forming giant impact.Science, Vol. 6272, pp. 493-496.MantleMeteorite

Abstract: Earth and the Moon are shown here to have indistinguishable oxygen isotope ratios, with a difference in ??17O of ?1 ± 5 parts per million (2 standard error). On the basis of these data and our new planet formation simulations that include a realistic model for primordial oxygen isotopic reservoirs, our results favor vigorous mixing during the giant impact and therefore a high-energy, high-angular-momentum impact. The results indicate that the late veneer impactors had an average ??17O within approximately 1 per mil of the terrestrial value, limiting possible sources for this late addition of mass to the Earth-Moon system.
DS201804-0704
2018
Jacoby, M.Jacoby, M.Carbonate mineral forms diamond on its own. New geological mechanism involving carbonate suggests Earth's lower mantle may be rich in diamond.cen.acs.org, Mar. 5, 1p.Mantlemeteorite

Abstract: When a meteorite slammed into Earth some 50,000 years ago, forming the bowl-shaped Xiuyan crater in northeast China, it left a treasure trove of geochemical research goodies. By applying microscopy and spectroscopy methods to analyze carbonate minerals found there, researchers have uncovered samples of diamond and a new mechanism for its formation.
DS2001-0523
2001
Jacoby, W.Jacoby, W.Mantle plumesJournal of Geodynamics, Vol. 32. No. 1-2, pp. 287-8.MantleHotspots
DS1999-0745
1999
Jacoby, W.R.Trubitsyn, V.P., Rykov, V.V., Jacoby, W.R.A self consistent 2 D model for the dip angle of mantle downflow beneath an overriding continent.Journal of Geodynamics, Vol. 28, No. 2-3, Sept. 2, pp. 215-224.MantleGeophysics - seismics, Subduction
DS200512-0943
2005
Jacome, M.I.Schmitz, M., Martins, A., Izarra, C., Jacome, M.I., Sanchez, J., Rocabado, V.The major features of the crustal structure in northeastern Venezuela from deep wide angle seismic observations and gravity modelling.Tectonophysics, Vol. 399, 1-4, April 27, pp. 109-124.South America, VenezuelaGeophysics - seismics, crustal structure, tectonics
DS201912-2790
2019
Jacq, K.Jacq, K., Giguet-Covex, C., Sabatier, P., Perrette, Y., Fanget, B., Coquin, D., Debret, M., Arnaud, F.High resolution grain size distribution of sediment core with hyperspectral imaging. ( not specific to diamond)Sedimentary Geology, Vol. 393-394, pdfGlobalhyperspectral

Abstract: The study of sediment cores allows for the reconstruction of past climate and environment through physical-chemical analysis. Nevertheless, this interpretation suffers from many drawbacks that can be overcome with the newest technologies. Hyperspectral imaging is one of these and allows a fast, high resolution, and non-destructive analysis of sediment cores. In this study, we use visible and near-infrared hyperspectral imaging to predict particle size fractions and distribution (PSD) at a resolution of 200??m on a previously well-studied sediment core taken from Lake Bourget (Western Alps, France). These predictions agree with previous studies on this core. Then, the PSD was used to estimate sedimentary deposit sources using the PSD unmixing algorithm AnalySize. It permitted estimation of the contribution of five sources (micrite, small and large bio-induced calcite crystals, diatom frustules, detrital particles), which had previously been characterized. The spatial dimension allowed for laminae to be discretized and counted, in agreement with the age-depth model previously established. We then evaluated the particle size and spectral signatures of each of these annual laminae, hence characterizing their physico-chemical composition. These high-resolution data also allowed for estimation of the accumulation rate (cm/year) of each of the main sources in the laminated unit and inferring the trophic status and the presence of instantaneous events of the lake.
DS1991-0779
1991
Jacques, A.L.Jacques, A.L., Hall, A.E., Sheraton, J., Smith, C.B., Roksandic, Z.Peridotitic paragenesis planar octahedral diamonds from the Ellendale lamproite pipes, western AustraliaProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 202-204AustraliaEllendale, Carbon isotope, Diamond morphology
DS1991-0780
1991
Jacques, A.L.Jacques, A.L., Knutson, J., Duncan, R.A review of the carbonatites of AustraliaProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 205-207AustraliaMount Weld, Ponton Creek, Cummins Range, Mundine Well, Mud Tank, Redbank, Walloway
DS201412-0209
2014
Jacques, A.L.Downes, P.J., Demeny, A., Czuppon, G., Jacques, A.L., Verrall, M., Sweetapple, M., Adams, D., McNaughton, N.J., Gwalani, L.G., Griffin, B.J.Stable H-C-O isotope and trace element geochemistry of the Cummins Range carbonatite complex, Kimberley region Western Australia: implications for hydrothermal REE mineralization, carbonatite evolution and mantle source regions.Mineralium Deposita, in press available 28p.AustraliaCarbonatite
DS202001-0021
2019
Jacques, J.F.Jacques, J.F.An eye on diamonds. The way diamonds are utilised for ophthalmic surgery.Gems & Jewellery, Vol. 28, 4, pp. 22-23.GlobalCryo-EM
DS201708-1677
2017
Jacques, L.Jacques, L.Insights into the petrogenesis of the West Kimberley lamproites from trace elements in olivine.11th. International Kimberlite Conference, OralAustralialamproites
DS201710-2245
2017
Jacquet, B.Mallard, C., Jacquet, B., Coltice, N.ADOPT: a tool for automatic detection of tectonic plates at the surface of convection model.Geochemistry, Geophysics, Geosystems, Vol. 18, 8, pp. 3197-3208.Mantletectonics

Abstract: Mantle convection models with plate-like behavior produce surface structures comparable to Earth's plate boundaries. However, analyzing those structures is a difficult task, since convection models produce, as on Earth, diffuse deformation and elusive plate boundaries. Therefore we present here and share a quantitative tool to identify plate boundaries and produce plate polygon layouts from results of numerical models of convection: Automatic Detection Of Plate Tectonics (ADOPT). This digital tool operates within the free open-source visualization software Paraview. It is based on image segmentation techniques to detect objects. The fundamental algorithm used in ADOPT is the watershed transform. We transform the output of convection models into a topographic map, the crest lines being the regions of deformation (plate boundaries) and the catchment basins being the plate interiors. We propose two generic protocols (the field and the distance methods) that we test against an independent visual detection of plate polygons. We show that ADOPT is effective to identify the smaller plates and to close plate polygons in areas where boundaries are diffuse or elusive. ADOPT allows the export of plate polygons in the standard OGR-GMT format for visualization, modification, and analysis under generic softwares like GMT or GPlates.
DS1860-1033
1898
Jacquet, J.B.Jacquet, J.B.Diamonds. In: Appendix No. 12New South Wales Geological Survey Report For 1897, P. 172.Australia, New South WalesDiamond Occurrence
DS1920-0387
1928
Jacquier, G.Jacquier, G.The Formation of Diamonds. Some Theories and Facts According to the Great French Mineralogist H. Moissan.Min. Ind. Magazine (johannesburg), Vol. 7, Dec. 26TH. PP. 413-415.GlobalDiamond Genesis
DS201412-0419
2014
Jacubek, J.Jacubek, J.From dream to reality …. Is it a mine?SRK and Friends Diamond Short Course, March 1, ppt p. 172-208.TechnologyMining methods
DS201906-1345
2019
Jadamec, M.Saylor, J.E., Finzel, E., Jadamec, M.Linking observations and modeling of flat-slab subduction. EOS.100, doi.org/10.1029/ 2019/EO122245United States, Montanasubduction
DS201611-2114
2016
Jadamec, M.A.Jadamec, M.A.Insights into slab-driven mantle flow from advances in three-dimensional modelling.Journal of Geodynamics, Vol. 100, pp. 51-70.MantleSubduction

Abstract: The wealth of seismic observations collected over the past 20 years has raised intriguing questions about the three-dimensional (3D) nature of the mantle flow field close to subduction zones and provided a valuable constraint for how the plate geometry may influence mantle flow proximal to the slab. In geodynamics, there has been a new direction of subduction zone modelling that has explored the 3D nature of slab-driven mantle flow, motivated in part by the observations from shear wave splitting, but also by the observed variations in slab geometries worldwide. Advances in high-performance computing are now allowing for an unprecedented level of detail to be incorporated into numerical models of subduction. This paper summarizes recent advances from 3D geodynamic models that reveal the complex nature of slab-driven mantle flow, including trench parallel flow, toroidal flow around slab edges, mantle upwelling at lateral slab edges, and small scale convection within the mantle wedge. This implies slab-driven mantle deformation zones occur in the asthenosphere proximal to the slab, wherein the mantle may commonly flow in a different direction and rate than the surface plates, implying laterally variable plate-mantle coupling. The 3D slab-driven mantle flow can explain, in part, the lateral transport of geochemical signatures in subduction zones. In addition, high-resolution geographically referenced models can inform the interpretation of slab structure, where seismic data are lacking. The incorporation of complex plate boundaries into high-resolution, 3D numerical models opens the door to a new avenue of research in model construction, data assimilation, and modelling workflows, and gives 3D immersive visualization a new role in scientific discovery.
DS201710-2242
2017
Jadamec, M.A.MacDougall, J.G., Jadamec, M.A., Fischer, K.M.The zone of influence of the subducting slab in the asthenospheric mantle.Journal of Geophysical Research: Solid Earth, Vol. 122, 8, pp. 6599-6624.Mantlesubduction

Abstract: Due to the multidisciplinary nature of combined geodynamics and shear wave splitting studies, there is still much to be understood in terms of isolating the contributions from mantle dynamics to the shear wave splitting signal, even in a two-dimensional (2-D) mantle flow framework. This paper investigates the viscous flow, lattice preferred orientation (LPO) development, and predicted shear wave splitting for a suite of buoyancy-driven subduction models using a non-linear rheology to shed light on the nature of the slab-driven asthenospheric flow and plate-mantle coupling. The slab-driven zone of influence in the mantle, LPO fabric, and resulting synthetic splitting are sensitive to slab strength and slab initial slab dip. The non-linear viscosity formulations leads to dynamic reductions in asthenospheric viscosity extending over 600 km into the mantle wedge and over 300 km behind the trench, with peak flow velocities occurring in models with a weaker slab and moderate slab dip. The olivine LPO fabric in the asthenosphere generally increases in alignment strength with increased proximity to the slab but can be transient and spatially variable on small length scales. The results suggest that LPO formed during initial subduction may persist into the steady state subduction regime. Vertical flow fields in the asthenosphere can produce shear wave splitting variations with back azimuth that deviate from the predictions of uniform trench-normal anisotropy, a result that bears on the interpretation of complexity in shear wave splitting observed in real subduction zones. Furthermore, the models demonstrate the corner flow paradigm should not be equated with a 2-D subduction framework.
DS201801-0026
2017
Jadhav, G.N.Jadhav, G.N., Viladkar, S.G., Goswami, R., Badhe, K.Fluid melt inclusions petrography of primary calcites from carbonatites of Amba Dongar, Gujarat India.Carbonatite-alkaline rocks and associated mineral deposits , Dec. 8-11, abstract p. 15.Indiadeposit - Amba Dongar

Abstract: The Amba Dongar Carbonatite complex consists of sovites which are dominantly composed of calcite along with pyrochlore, phlogopite, apatite, barite, ankerite and haematite and minor opaques such as magnetite, chalcopyrite and pyrite. Two distinct types of texture are present in these carbonatites- a mosaic of equigranular calcite crystals and porphyritic texture. Silicate melt inclusions are observed in primary minerals viz. apatite and calcites. These are small droplets of silicate melt entrapped during the growth of the minerals. In this case carbonatite-alkaline silicate melt inclusions are entrapped predominantly in calcite crystals. Dominantly these calcite host minerals are predominantly containing fluid inclusions along with halite, sylvite and minor nahcolite as daughter crystals. The presence of calcite with nahcolite indicates the coexistence of a Ca-rich, alkali-bearing carbonatite melt phase. The melt inclusions are heated upto 1100 °C and the carbonate melt inclusions appear to be homogenized around 950 °C. This fall within the range of melting temperature of a carbonatite melt. In addition to these, three types of fluid inclusions were also observed in host calcite they are i) monophase, ii) biphase and iii) polyphase types of fluid inclusions. The fluid inclusions contain CO2 gas, Li-K carbonate phases and fergusonite based on Micro-Laser- Raman. Carbon dioxide is the dominant gas phase in most of the fluid inclusions, indicating high temperature and deep mantle source(?). The fluid inclusions have formed from a primary mother liquor that has separated out from the early formed carbonatitic melt. This fluid was either formed just after the formation of melt inclusions or during simultaneous crystallization from a carbonatitic or to be more precise carbonatiticpegmatite melt(?).The presence of both melt and fluid inclusions in these primary calcite host minerals indicates the presence of a carbonatitic-pegmatitic fluid, which must have got separated out from the early formed carbonatite-alkaline silicate magma.
DS1991-1496
1991
Jadhav, P.C.Sant, D.A., Karanth, R.V., Jadhav, P.C.A note on the occurrence of carbonatite dykes in the Lower Narmada ValleyJournal of Geological Society India, Vol. 37, Feb. pp. 119-127IndiaCarbonatite, Petrology
DS1970-0318
1971
Jadia, P.L.Jadia, P.L.Preparation of Diamond Roughs for the MarketIndia Geological Survey Miscellaneous Publishing, No. 19, PP. 203-207.IndiaMineral Economics
DS1970-0319
1971
Jadia, P.L.Jadia, P.L.Diamondiferous Alluvials of RamkheriaIndia Geological Survey Miscellaneous Publishing, No. 19, PP. 86-91.IndiaSampling, Prospecting, Alluvial Placer Deposits
DS1995-1317
1995
Jaeckel, P.Munyanyiwa, H., Kroner, A., Jaeckel, P.uranium-lead (U-Pb) and lead lead single zircon ages for the chrno-enderbites from the Magondimobile beltSouth African Journal of Geology, Vol. 98, No. 1, March pp. 52-57ZimbabweGeochronology, Magondi belt
DS1996-1033
1996
JaegerNewsom, H.E., Sims, Noll, Jaeger, Maehr, BesserraThe depletion of tungsten in the bulk silicate earth: constraints on coreformation.Geochimica et Cosmochimica Acta, Vol. 60, No. 7, pp. 1155-69.MantleGeochemistry - bulk silicate EARTH backscatter electron (BSE) imaging ., Core formation
DS1920-0340
1927
Jaeger, F.Jaeger, F.Die Diamantenwueste SuedwestafrikasZeitschr. Geogr. (leipzig), Vol. 33, PP. 321-329.Southwest Africa, NamibiaGeology, Geomorphology
DS200612-0839
2006
Jaeger-Frank, E.Ludascher, B., Lin, K., Bowers, S., Jaeger-Frank, E., Brodaric, B., Baru, C.Managing scientific dat a: from dat a integration to scientific workflows.In: Sinha, A.K. Geoinformatics: data to knowledge, GSA Special Paper, 397, 397,pp.109-30TechnologyData - not specific to diamonds
DS201012-0318
2010
Jaesok, L.Jaesok, L., Haemycong, J.Lattice preferred orientation of olivine in garnet peridotites from Finsch, South Africa.International Mineralogical Association meeting August Budapest, abstract p. 216.Africa, South AfricaSpectroscopy
DS202004-0500
2020
Jaffal, M.Ba, M.H., Ibough, H., Lo, K., Youbi, N., Jaffal, M., Ernst, R.E., Niang, A.J., Dia, I., Abdeina, E.H., Bensalah, M.K., Boumehdi, M.A., Soderlund, U.Spatial and temporal distribution patterns of Precambrian mafic dyke swarms in northern Mauritania ( West African Craton): analysis and results fro remote sensing interpretation, geographical information systems ( GIS), Google Earth TM images, and regionaArabian Journal of Geosciences, Vol. 13, , 209 orchid.org/ 0000-002-3287-9537Africa, Mauritaniacraton

Abstract: We used remote sensing, geographical information systems, Google Earth™ images, and regional geology in order to (i) improve the mapping of linear structures and understand the chronology of different mafic dyke swarms in the Ahmeyim area that belongs to the Archean Tasiast-Tijirit Terrane of the Reguibat Shield, West African craton, NW Mauritania. The spatial and temporal distributions with the trends of the dyke swarms provide important information about geodynamics. The analysis of the mafic dyke swarms map and statistical data allow us to distinguish four mafic dyke swarm sets: a major swarm trending NE-SW to NNE-SSW (80%) and three minor swarms trending EW to ENE-WSW (9.33%), NW-SE to WNW-ESE (9.06%), and NS (1.3%). The major swarms extend over 35 km while the minor swarms do not exceed 13 km. The Google Earth™ images reveal relative ages through crossover relationships. The major NE-SW to NNE-SSW and the minor NS swarms are the oldest generations emplaced in the Ahemyim area. The NW-SE-oriented swarm dykes which are cutting the two former swarms are emplaced later. The minor E-W to WSW-ENE swarms are probably the youngest. A precise U-Pb baddeleyite age of 2733?±?2 Ma has been obtained for the NNE-SSW Ahmeyim Great Dyke. This dyke is approximately 1500 m wide in some zone and extends for more than 150 km. The distinct mafic dyke swarms being identified in this study can potentially be linked with coeval magmatic events on other cratons around the globe to identify reconstructed LIPs and constrain continental reconstructions.
DS201810-2338
2018
Jaffri, S.H.Khanna, T.C., Sesha Sai, V.V., Jaffri, S.H., Keshav Krishna, A., Korakoppa, M.M.Boninites in the ~3.3 Ga Holenarsipur greenstone belt, western Dharwar Craton, India.MDPI Geosciences, Researchgate 17p.Indiaboninites

Abstract: In this contribution, we present detailed field, petrography, mineral chemistry, and geochemistry of newly identified high-Si high-Mg metavolcanic rocks from the southern part of the ~3.3 Ga Holenarsipur greenstone belt in the western Dharwar craton, India. The rocks occur as conformable bands that were interleaved with the mafic-ultramafic units. The entire volcanic package exhibits uniform foliation pattern, and metamorphosed under greenschist to low grade amphibolite facies conditions. The rocks are extremely fine grained and exhibit relict primary igneous textures. They are composed of orthopyroxene and clinopyroxene phenocrysts with serpentine, talc, and amphibole (altered clinopyroxene). Cr-spinel, rutile, ilmenite, and apatite occur as disseminated minute grains in the groundmass. The mineralogical composition and the geochemical signatures comprising of high SiO2 (~53 wt. %), Mg# (~83), low TiO2 (~0.18 wt. %), and higher than chondritic Al2O3/TiO2 ratio (~26), reversely fractionated heavy rare earth elements (REE) (GdN/YbN ~ 0.8), resulting in concave-up patterns, and positive Zr anomaly, typically resembled with the Phanerozoic boninites. Depletion in the high field strength elements Nb, and Ti relative to Th and the REE in a primitive mantle normalized trace element variation diagram, cannot account for contamination by pre-existing Mesoarchean continental crust present in the study area. The trace element attributes instead suggest an intraoceanic subduction-related tectonic setting for the genesis of these rocks. Accordingly, the Holenarsipur high-Si high-Mg metavolcanic rocks have been identified as boninites. It importantly indicates that the geodynamic process involved in the generation of Archean boninites, was perhaps not significantly different from the widely recognized two-stage melt generation process that produced the Phanerozoic boninites, and hence provides compelling evidence for the onset of Phanerozoic type plate tectonic processes by at least ~3.3 Ga, in the Earth’s evolutionary history.
DS201012-0319
2010
Jafri, S.S.H.Jafri, S.S.H., Moeen, S., Dayal, A.M., Narayana, B.L.High silica lamproite dykes from Schirmacher Oasis, Queen Maud Land, Antarctica.International Dyke Conference Held Feb. 6, India, 1p. AbstractAntarcticaLamproite
DS1989-1078
1989
Jagannadha Rao, S.Murthy Radhakrishna, I.V., Jagannadha Rao, S.A fortran 77 program for inverting gravity anomalies of two dimensional basement structuresComputers and Geosciences, Vol. 15, No. 7, pp. 1149-1156. Database #18197GlobalGeophysics, Tectonics basement structure, Computer- program Fortran 77
DS1993-0731
1993
Jagannadha Rao, S.Jagannadha Rao, S., et al.Automatic inversion of self-potential anomalies of sheet-like bodiesComputers and Geosciences, Vol. 19, No. 1, pp. 61-73IndiaGeophysics -Special Paper, Sulphides, graphite, computer applications
DS2003-0538
2003
Jagger, K.Hamblin, A.P., Stasiuk, L.D., Sweet, L.D., Lockhart, G., Dyck, D.R., Jagger, K.Post kimberlite Eocene strat a in Crater Basin, Lac de Gras, Northwest Territories8ikc, Www.venuewest.com/8ikc/program.htm, Session 1 POSTER abstractNorthwest TerritoriesKimberlite geology and economics, Stratigraphy
DS200712-0478
2007
Jaglinski, T.Jaglinski, T., Kochmann, D., Stone, D., Lakes, R.S.Composite materials with viscoelastic stiffness greater than diamond.Science, No. 5812, Feb. 2, pp. 620-621.TechnologyChemistry
DS1860-0468
1885
Jagnaux, R.Jagnaux, R.Traite Mineralogie Applique Aux Arts l'industrie....Paris: Octave Doin., 883P.GlobalMineralogy
DS2003-0637
2003
Jago, B.Jago, B.Diamond sample processing and dat a interpretationSme Annual Meeting, February 24-26, ( Brief Abstract), 1/8p.GlobalNews item, Technology
DS1980-0182
1980
Jago, B.C.Jago, B.C.Geology of a Portion of the Western Contact Margin, the Coldwell Complex.Bsc. Thesis, Lakehead University, Canada, OntarioAlkaline Rocks, Carbonatite
DS1982-0294
1982
Jago, B.C.Jago, B.C.Mineralogy and Petrology of the Ham Kimberlite, Somerset Island, Northwest Territories, Canada.Thunder Bay: Msc. Thesis, Lakehead University, 235P.Canada, Northwest Territories, Batty BayGarnet, Geothermometry, Geobarometry, Geophysics, Geochemistry
DS1985-0305
1985
Jago, B.C.Jago, B.C., Mitchell, R.H.Mineralogy and petrology of the Ham kimberlite Somerset IslandNorthwestTerritoriesCanadian Mineralogist, Vol. 23, pp. 619-634Northwest TerritoriesBlank
DS1986-0394
1986
Jago, B.C.Jago, B.C., Mitchell, R.H.The statistical classification of kimberlite garnet by devisive cluster analysis and multiple discriminant analysisProceedings of the Fourth International Kimberlite Conference, Held Perth, Australia, No. 16, pp. 42-44Northwest TerritoriesSomserset Island, Geochemistry
DS1987-0315
1987
Jago, B.C.Jago, B.C., Mitchell, R.H.Ultrabasic xenoliths from the Ham kimberlite, Somerset Island,NorthwestTerritoriesCanadian Mineralogist, Vol. 25, pt. 3 September pp. 515-525Northwest TerritoriesGeothermobarometry
DS1987-0316
1987
Jago, B.C.Jago, B.C., Mitchell, R.H.A new garnet classification technique: divisive cluster analysis applied to garnet populations from Somerset Island kimberlites #2Fourth International Kimberlite Conference, In pressNorthwest TerritoriesSomerset Island, Garnet
DS1989-0515
1989
Jago, B.C.Gittins, J., Jago, B.C.Calcitic carbonatite lavas reinterpreted; their significance for magmagenesisNew Mexico Bureau of Mines Bulletin., Continental Magmatism Abstract Volume, Held, Bulletin. No. 131, p. 108. AbstractGlobalCarbonatite
DS1989-0695
1989
Jago, B.C.Jago, B.C., Mitchell, R.H.A new garnet classification technique: divisive cluster analysis applied to garnet populations from Somerset Island kimberlites #1Geological Society of Australia Inc. Blackwell Scientific Publishing, Special, No. 14, Vol. 1, pp. 297-310Northwest Territories, Somerset IslandAnalysis, Garnets
DS1990-0574
1990
Jago, B.C.Gittins, J., Beckett, M.F., Jago, B.C.Composition of the fluid phase accompanying carbonatite magma: a criticalexaminationAmerican Mineralogist, Vol. 75, No. 9-10. Sept.-Oct. pp. 1106-1109QuebecOka, Husereau Hill, Carbonatite
DS1990-0575
1990
Jago, B.C.Gittins, J., Jago, B.C.Carbonatite lavas: the role of fluorine, chlorine and water in carbonatitemagmasTerra, Abstracts of Experimental mineralogy, petrology and, Vol. 2, December abstracts p. 76GlobalCarbonatite, Experimental petrology
DS1990-0751
1990
Jago, B.C.Jago, B.C., Gittins, J.Comparative roles of fluorine and water in carbonatite magma evolutionTerra, Abstracts of Experimental mineralogy, petrology and, Vol. 2, December abstracts p. 82GlobalExperimental Petrology, Carbonatite
DS1991-0578
1991
Jago, B.C.Gittins, J., Jago, B.C.Extrusive carbonatites: their origins reappraised in the light of new experimental dataGeological Magazine, Vol. 128, No. 4, July pp. 301-305GlobalExperimental petrology, Carbonatite
DS1991-0781
1991
Jago, B.C.Jago, B.C.The role of fluorine in the evolution of alkali-bearing carbonatite magma sand the formation of carbonatite-hosted apatite and pyrochlore depositsPh.d. thesis University of Toronto, 410p, MantleGeochemistry, Carbonatite
DS1991-0782
1991
Jago, B.C.Jago, B.C., Gittins, J.The role of fluorine in the crystallization of niobium and phosphorous ores in carbonatitesProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 193-195GlobalPyrochlore, apatite, Experimental petrology
DS1991-0783
1991
Jago, B.C.Jago, B.C., Gittins, J.The role of fluorine in carbonatite magma evolutionNature, Vol. 349, No. 6304, January 3, pp. 56-58TanzaniaCarbonatite, Oldoinyo Lengai -fluorine
DS1992-0576
1992
Jago, B.C.Gittins, J., Beckett, M.F., Jago, B.C.Composition of the fluid phase accompanying carbonatite magmas: acritical examination- replyAmerican Mineralogist, Vol. 77, No. 5, 6, May-June pp. 666-667GlobalCarbonatite, Petrology
DS1992-0577
1992
Jago, B.C.Gittins, J., Jago, B.C.The role of fluorine in the crystallization and evolution of carbonatitemagmasEos Transactions, Vol. 73, No. 14, April 7, supplement abstracts p.349GlobalCarbonatite, Fluorine
DS1993-0732
1993
Jago, B.C.Jago, B.C.Petrology and mineralogy of kimberlite and diamond indicator mineralsQuebec Exploration Conference summaries held September 15-1th. Val d'Or, pp. 3-5GlobalBrief overview petrology
DS1993-0733
1993
Jago, B.C.Jago, B.C.The tentative field identification of kimberlite and what should happennext: a short course definition, classification, petrology, mineralogy andprelim. eval. evalPreprint from author, 34pGlobalKimberlite, Field identification notes
DS1993-0734
1993
Jago, B.C.Jago, B.C., Gittins, J.Pyrochlore crystallization in carbonatites: the role of fluorineSouth African Journal of Geology, Vol. 96, No. 3, Sept. pp. 149-159.TanzaniaCarbonatite -pyrochlore, Petrology -experimental
DS1994-0823
1994
Jago, B.C.Jago, B.C., Gittins, J.Solubility of water in carbonatite magmas and partitioning of Fluorine and Chlorine between magma and aequeous fluid.Geological Association of Canada (GAC) Abstract Volume, Vol. 19, p.GlobalCarbonatite, Petrology -experimental
DS1998-0515
1998
Jago, B.C.Gittins, J., Jago, B.C.Differentiation of natrocarbonatite magma at Oldoinyo Lengai volcano, Tanzania.Mineralogical Magazine, Vol. 62, No. 6, Dec. 1, pp. 759-68.TanzaniaCarbonatite, Deposit - Oldoinyo Lengai
DS1999-0331
1999
Jago, B.C.Jago, B.C., Gittins, J.Manganese and Fluorine bearing rasvumite in natrocarbonatite at Oldoinyo Lengai Tanzania.Mineralogical Magazine, Vol. 63, No. 1, pp. 53-5.TanzaniaCarbonatite, Deposit - Oldoinyo Lengai
DS2000-0439
2000
Jago, B.C.Jago, B.C.Mineralogy and microdiamonds - diamond exploration toolsSociety for Mining, Metallurgy and Exploration (SME) preprint, Feb. 27GlobalDiamond - technology - microdiamonds
DS2001-0524
2001
Jago, B.C.Jago, B.C.Mineralogy and microdiamonds - evaluating a diamond prospectOntario Geological Survey, Northeastern Mineral Symposium, p.12-3, abstract.Ontario, WawaSampling - analyses
DS2002-0758
2002
Jago, B.C.Jago, B.C., Davis, D., Derbuch, H.Diamonds on the Brodeur Peninsula - a new kimberlite province in Nunuvut, CanadaC.i.m. Bulletin, Vol. 95, No. 1061, May, pp. 72-78.Nunavut, Brodeur Peninsula, Baffin IslandGeology, geophysics, petrology, mineralogy, Deposit - Freightrain
DS2003-0638
2003
Jago, B.C.Jago, B.C., Davis, D., Derbuch, H.Diamond indicator mineral chemistry in relation to diamond potential - the Brodeur31st Yellowknife Geoscience Forum, p. 44-5. (abst.Nunavut, Brodeur Peninsula, Somerset IslandMineral chemistry
DS2003-0639
2003
Jago, B.C.Jago, B.C., Lindsay, J., De Belder, D., Davis, D.W.Diamond grade and quality in relation to mineral chemistry of Twin Mining's Jackson31st Yellowknife Geoscience Forum, p. 46. (abst.Nunavut, Brodeur PeninsulaMineral chemistry
DS200412-0895
2003
Jago, B.C.Jago, B.C., Davis, D., Derbuch, H.Diamond indicator mineral chemistry in relation to diamond potential - the Brodeur Peninsula kimberlite province vs Somerset isl31st Yellowknife Geoscience Forum, p. 44-5. (abst.Canada, Nunavut, Brodeur Peninsula, Somerset IslandMineral chemistry
DS200412-0896
2003
Jago, B.C.Jago, B.C., Lindsay, J., De Belder, D., Davis, D.W.Diamond grade and quality in relation to mineral chemistry of Twin Mining's Jackson In let FreightTrain kimberlite, Brodeur Penin31st Yellowknife Geoscience Forum, p. 46. (abst.Canada, Nunavut, Brodeur PeninsulaMineral chemistry
DS201112-0473
1982
Jago, B.C.Jago, B.C.Mineralogy and petrology of the Ham kimberlite, Somerset Island, N.W.T. Canada.Thesis: Msc. Lakehead University, Canada, Northwest TerritoriesThesis - note availability based on request to author
DS1986-0751
1986
JagoutzSmith, C.B., Allsopp, H.L., Kramers, J.D., Gurney, J.J., JagoutzIsotopic and geochemical studies of kimberlitic and included xenolithsProceedings of the Fourth International Kimberlite Conference, Held Perth, Australia, No. 16, pp. 329-331South Africa, BotswanaBlank
DS2000-0886
2000
JagoutzShatskii, V.S., Simonov, Jagoutz, Kozmenko, KurenkovNew dat a on the age of eclogites from the Polar UralsDoklady Academy of Sciences, Vol. 371a, No. 3, Mar-Apr. pp. 534-8.Russia, UralsEclogites, Geochronology
DS1983-0328
1983
Jagoutz, E.Jagoutz, E., Spettel, B., Waenke, H., Dawson, B.Identification of Early Differentiation Processes on the Earth.Meteoritics, Vol. 18, No. 4, PP. 319-320. (abstract.).GlobalGeochemistry, Kimberlite, Ultramafics
DS1984-0375
1984
Jagoutz, E.Jagoutz, E., Dawson, J.B., Hoernes, S., Spettel, B., Waenke, H.Anorthositic Oceanic Crust in the Archean EarthLunar and Planetary Science Conference 15th. Abstract Volume, Vol. 15, pp. 395-396GlobalAnorthosite
DS1986-0395
1986
Jagoutz, E.Jagoutz, E.samarium-neodymium (Sm-Nd) systematics in eclogites from SiberiaProceedings of the Fourth International Kimberlite Conference, Held Perth, Australia, No. 16, pp. 265-266RussiaEclogite
DS1986-0708
1986
Jagoutz, E.Schier, D., Jagoutz, E.Cerium isotopes- new aspects for kimberlite genesis by a newisotopicsystemProceedings of the Fourth International Kimberlite Conference, Held Perth, Australia, No. 16, pp. 318-319South AfricaBlank
DS1987-0689
1987
Jagoutz, E.Smith, C.B., Kramers, J.D., Jagoutz, E.Subcalcic megacrysts in kimberlite: deep lithosphere orasthenosphereorigins?Terra Cognita, Conference abstracts Oceanic and Continental Lithosphere:, Vol. 7, No. 4, Autumn, abstract only p. 624South AfricaBlank
DS1988-0323
1988
Jagoutz, E.Jagoutz, E.neodymium and Strontium systematics in an eclogite xenolith from Tanzania:evidence for frozen mineral equilibration temperatures in the continentallithosphereGeochimica et Cosmochimica Acta, Vol. 52, No. 5, May pp. 1285-194TanzaniaBlank
DS1988-0784
1988
Jagoutz, E.Zindler, A., Jagoutz, E.Mantle cryptologyGeochimica et Cosmochimica Acta, Vol. 52, No. 2, February pp. 319-333GlobalBlank
DS1989-0696
1989
Jagoutz, E.Jagoutz, E., Shatsky, V.S., Sobolev, N.V., Pokhilenko, N.P.lead-neodymium-Sr isotope study of the Kokchetav Massif;the outcrop of the lowerlithosphereDiamond Workshop, International Geological Congress, July 15-16th. editors, pp. 32-35. AbstractRussiaMantle, Geochronology
DS1990-0752
1990
Jagoutz, E.Jagoutz, E., Shatsky, V.S., Sobolev, N.V.Sr-Neodymium-Palladium isotopic study of ultra high pressuret rocks from Kokchetav massifEos, Vol. 71, No. 43, October 23, p. 1707 AbstractRussiaMetamorphic rocks, Diamonds
DS1990-1341
1990
Jagoutz, E.Shatskii, V.S., Jagoutz, E., Sobolev, N.V., Kozmenko, O.A.Geochemical characteristics of crustal rocks subducted into the uppermantleEos, Vol. 71, No. 43, October 23, p. 1707 AbstractRussiaMetamorphic rocks, Diamonds
DS1991-0638
1991
Jagoutz, E.Guther, M., Jagoutz, E.Systematics of isotopic disequilibration temperatures between minerals of low temperature garnet lherzolitesProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 122-124South AfricaGeochronology -isotopes
DS1991-0777
1991
Jagoutz, E.Jacob, D., Jagoutz, E., Sobolev, N.V.A diamond graphite bearing eclogitic xenolith from Roberts Victor-indication for petrogenesis from lead, neodymium, and Sr isotopesProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 190-192South AfricaGeochronology, Geochemistry
DS1991-0925
1991
Jagoutz, E.Kovalenko, V.I., Ionov, D.A., Yarmolyuk, V.V., Jagoutz, E.Isotope dat a on the evolution of the mantle and its correlation with the evolution of the crust in some parts of central AsiaGeochemistry International, Vol. 28, No. 4, pp. 82-92China, RussiaMantle, Geochronology
DS1992-0768
1992
Jagoutz, E.Jagoutz, E.Isotopic systematics of ultra high pressureT rocksProceedings of the 29th International Geological Congress. Held Japan August 1992, Vol. 2, abstract p. 598RussiaDiamond, Crustal rocks
DS1993-0728
1993
Jagoutz, E.Jacob, D., Jagoutz, E., et al.Diamondiferous eclogites from Siberia: ancient oceanic crustAmerican Geophysical Union, EOS, supplement Abstract Volume, October, Vol. 74, No. 43, October 26, abstract p. 637.Russia, SiberiaEclogite
DS1993-0729
1993
Jagoutz, E.Jacob, D.E., Jagoutz, E., Sobolev, N.V.Isotopic systematics of subcalcic garnets from SiberiaEos, Transactions, American Geophysical Union, Vol. 74, No. 16, April 20, supplement abstract p. 320Russia, SiberiaGeochemistry -garnets, Geochronology
DS1993-1442
1993
Jagoutz, E.Shatsky, V.S., Jagoutz, E., Kozmenko, O.A., Blinchik, T.M., Sobolev, N.V.Age and genesis of eclogites from the Kokchetav massif (northernKazakhstan).Russian Geology and Geophysics, Vol. 34, No. 12, pp. 40-50.Russia, KazakhstanGeochronology, Eclogites
DS1994-0674
1994
Jagoutz, E.Gunther, M., Jagoutz, E.Isotopic disequilibration temperatures (Samarium/neodymium, Rubidium-Strontium) between mineral phases of coarse grained, low temperature garnet peridotites from Kimberley Floors.Proceedings of Fifth International Kimberlite Conference, Vol. 1, pp. 354-365.South AfricaPeridotites, Deposit -Kimberley Floors
DS1994-0819
1994
Jagoutz, E.Jacob, D., Jagoutz, E.A diamond graphite bearing eclogitic xenoliths from Roberts Victor (SouthAfrica) -indication for petrogenesis from lead neodymium and Sr isotopes.Proceedings of Fifth International Kimberlite Conference, Vol. 1, pp. 304-317.South AfricaGeochronology, Deposit -Roberts Victor
DS1994-0820
1994
Jagoutz, E.Jacob, D., Jagoutz, E., Lowry, D., Mattey, D., KudrjavtsevaDiamondiferous eclogites from Siberia: remnants of Archean oceanic crustGeochimica et Cosmochimica Acta, Vol. 58, 23, pp. 5191-207.Russia, SiberiaEclogites, Deposit -Udachnaya
DS1994-0821
1994
Jagoutz, E.Jacob, D.E., Jagoutz, E., Lowry, D., et al.Diamondiferous eclogites from Udachnaya: a subducted component in the Siberian upper mantle.Mineralogical Magazine, Vol. 58A, pp. 448-449. AbstractRussia, SiberiaEclogites, diamond genesis, Deposit -Udachnaya
DS1995-0442
1995
Jagoutz, E.Dreibus, G., Jagoutz, E., Wanke, H.Water in the earth's mantleProceedings of the Sixth International Kimberlite Conference Extended Abstracts, p. 141-2.MantleAccretion model -water
DS1995-0700
1995
Jagoutz, E.Gunther, M., Jagoutz, E.Age informations in kimberlite derived low temperature garnet lherzolite xenoliths -what do they mean?Terra Nova, Abstract Vol., p. 334.South AfricaXenoliths, Kimberlite
DS1995-0701
1995
Jagoutz, E.Gunther, M., Jagoutz, E.Ages and processes as reported by isotopes of kimberlite derived low temperature lherzolites.Proceedings of the Sixth International Kimberlite Conference Extended Abstracts, p. 205-7.South Africa, Russia, SiberiaGeochronology, Deposit -Kimberley Floors, Jagersfontein, Udachnaya, Mir
DS1995-0862
1995
Jagoutz, E.Jacob, D.E., Jagoutz, E., Sobolev, N.V., Sorowka, A.Isotopic analysis ( Samarium/neodymium, Rubidium-Strontium and Uranium/lead) of single subcalcic garnet grains from Yakutian kimberlites.Proceedings of the Sixth International Kimberlite Conference Abstracts, pp. 257-259.Russia, YakutiaGeochemistry, isotopes, Geochronology -garnets
DS1995-1720
1995
Jagoutz, E.Shatsky, V.S., Sobolev, N.V., Jagoutz, E., Vavilov, M.A.Ultrahigh pressure metamorphic environment of microdiamondsProceedings of the Sixth International Kimberlite Conference Abstracts, pp. 512-514.Russia, KazakhstanMetamorphic, Deposit -Kokchetav Massif
DS1997-1028
1997
Jagoutz, E.Shatsky, V.S., Jagoutz, E., Kozmenko, O.A.Sm neodymium dating of the high pressure metamorphism of the Maksyutov Complex, southern Urals.Doklady Academy of Sciences, Vol. 353, No. 2, Feb-Mar, pp. 285-8.Russia, UralsGeochronology, ultra high pressure (UHP)
DS1998-0672
1998
Jagoutz, E.Jacob, D., Jagoutz, E., Zinngrebe, E., Snyder, TaylorComment and reply on the origins of Yakutian eclogite xenolithsJournal of Petrology, Vol. 39, No. 8, Aug. 1, pp. 1527-1539.Russia, YakutiaEclogites, Diamond genesis
DS1998-0674
1998
Jagoutz, E.Jacob, D.E., Jagoutz, E., Sobolev, N.V.Neodynium and strontium isotopic measurements on single subcalcic garnet grains from Yakutian kimberlites.Neues Jahrbuch f?r Mineralogie Abh., No. 172, pp. 357-379.Russia, YakutiaGeochronology
DS1998-1246
1998
Jagoutz, E.Roden, M.F., Lazko, E.E., Jagoutz, E.Petrology and geochemistry of peridotite inclusions from the Mirkimberlite, Siberia.7th. Kimberlite Conference abstract, pp. 741-2.Russia, Siberia, YakutiaXenoliths - inclusions, Deposit - Mir
DS1999-0606
1999
Jagoutz, E.Roden, M.F., Lazko, E.E., Jagoutz, E.The role of garnet pyroxenites in the Siberian lithosphere: evidence from the Mir kimberlite.7th International Kimberlite Conference Nixon, Vol. 2, pp. 714-20.Russia, Siberia, YakutiaMineralogy, thermobarometry, mineral chemistry, analyse, Deposit - Mir
DS2003-0631
2003
Jagoutz, E.Jacob, D.E., Fung, A., Jagoutz, E., Pearson, D.G.Petrology and geochemistry of eclogite xenoliths from the Ekati kimberlite area8ikc, Www.venuewest.com/8ikc/program.htm, Session 2, POSTER abstractNorthwest TerritoriesEclogites and Diamonds, Deposit - Ekati
DS2003-0640
2003
Jagoutz, E.Jagoutz, E., Dreibus, G.On the search for 142 Nd in terrestrial rocks8 Ikc Www.venuewest.com/8ikc/program.htm, Session 4, AbstractSouth Africa, Russia, SiberiaMantle geochemistry, Lherzolitic nodules
DS2003-1175
2003
Jagoutz, E.Roden, M., Patino-Douce, A., Lazko, E., Jagoutz, E.Exsolution textures in high pressure garnets, Mir kimberlite, Sibveria8 Ikc Www.venuewest.com/8ikc/program.htm, Session 6, POSTER abstractRussia, SiberiaDeposit - Mir
DS200412-0897
2003
Jagoutz, E.Jagoutz, E., Dreibus, G.On the search for 142 Nd in terrestrial rocks.8 IKC Program, Session 4, AbstractAfrica, South Africa, Russia, SiberiaMantle geochemistry Lherzolitic nodules
DS200412-1680
2003
Jagoutz, E.Roden, M., Patino-Douce, A., Lazko, E., Jagoutz, E.Exsolution textures in high pressure garnets, Mir kimberlite, Sibveria.8 IKC Program, Session 6, POSTER abstractRussia, SiberiaMantle petrology Deposit - Mir
DS200512-0462
2005
Jagoutz, E.Ionov, D.A., Ashchepkov, I., Jagoutz, E.The provenance of fertile off craton lithospheric mantle: Sr Nd isotope chemical composition of garnet and spinel peridotite xenoliths from Vitim, Siberia.Chemical Geology, Vol. 217, 1-2, April 15, pp. 41-75.Russia, SiberiaGeochronology
DS200612-1165
2006
Jagoutz, E.Roden, M.F., Paino-Douce, A.E., Jagoutz, E., Lazko, E.E.High pressure petrogenesis of Mg rich garnet pyroxenites from Mir kimberlite, Russia.Lithos, Vol. 90, 1-2, pp. 77-91.Russia, SiberiaMajorite
DS200612-1166
2006
Jagoutz, E.Roden, M.F., PatinoDouce, A.E., Jagoutz, E., Lazko, E.E.High pressure petrogenesis of Mg rich garnet pyroxenites from Mir kimberlite, Russia.Lithos, Vol.90, 1-2, August pp. 77-91.Russia, YakutiaDeposit - Mir, petrology
DS201907-1572
2019
Jagoutz, E.Shatsky, V., Jagoutz, E., Kozmenko, O., Ragozin, A., Skuzovatov, S., Sobolev, N.The protolith nature of diamondiferous metamorphic rocks of the Kokchetav Massif.Acta Geologica Sinica, Vol. 93, 1, p. 173-Russiadeposit - Kokchetav

Abstract: International Symposium on Deep Earth Exploration and Practices Beijing, China -October24-26, 2018The protolithnatureof diamondiferous metamorphic rocks of the Kokchetav MassifVladislav Shatsky1,2,3, Emil Jagoutz4, Olga Kozmenko1, Alexey Ragozin1,3, Sergei Skuzovatov2and Nikolai Sobolev1,31Sobolev Institute of Geology and Mineralogy SB RAS, Novosibirsk, 630090, Russia, [email protected] Institute of Geochemistry SB RAS, Irkutsk, Russia3Novosibirsk State University, Novosibirsk, Russia4Max Planck Institute for Chemistry, Mainz, GermanyUltra-high-pressure diamondiferous rocks (UHP) of the Kokchetav subduction-collision zone are considered as an idealobject for studying the mobility of elements insubduction zones of the continental type. The compositional diversity of metasedimentary rocks subjected to UHP metamorphism makes it difficult to establish the nature of their protoliths. This, in turn, complicates estimatesof the degree of depletionof the UHP metamorphic rocks relative to the protoliths.To clarify the nature of protholiths of the Kokchetav diamondiferous rocks we studied the geochemical features and Sm-Nd isotopic composition of diamondiferous calc-silicate, garnet-pyroxene rocks, high-alumina metapelitesand barren granite-gneisses.The nine samples of the Kumdy Kol mocrodiamond deposit (one granite-gneiss, 4-calc-silicate rocks, 3-garnet-pyroxenite) yielded aSm-Nd whole-rockisochronageof 1052±44 Ma. This age is close to the age of formation of the granitic gneiss basement of the Kokchetav massif (1.2-1.05 Ga) (Glorie et al., 2015). Therefore, we assume that the protoliths of these rocks were basementrocks. In this interpretation, their geochemical features may not be directly related to the processes of ultrahigh-pressure metamorphism.At the same time, the high-alumina rocks of the Barchinsky area are depleted todifferent degreeswithrespect to LREE and K yieldeda whole-rockisochron with an age of 509 ± 32 Ma, which suggests partial melting of these rocks duringthe exhumation stage.It was previously assumed that metasedimentary rocks of the Kokchetav microcontinent are the protoliths of diamondiferous rocks (Buslov et al., 2015). However, this contradicts with Sm-Nd isotopic data for metasedimentary rocks of quartzite-schist sequences of the Kokchetav microcontinent (Kovach et al., 2017). The metasedimentary rocks of the Sharyk Formation are characterized by variations in the ?Nd(t)from +4.1 to -3.3 and intNd(DM)from 1.9 to 1.25 Ga, whereasin the UHP metamorphic rocks ?Nd(t)varies from -7.6 to -13.2, and the model ages range from 2.7 to 2.3 Ga. These data clearly indicate that the metasedimentary rocks of the Kokchetav massif could not be the protolith of the ultrahigh-pressure rocks.
DS200612-1270
2005
Jagoutz, F.Shatsky, V.S., Buzlukova, L.V., Jagoutz, F., Kozmenko, O.A., Mityukhin, S.I.Structure and evolution of the lower crust of the Daldyn Alakit district in the Yakutian diamond province ( from dat a on xenoliths).Russian Geology and Geophysics, Vol. 46, 12, pp. 1252-1270.Russia, YakutiaPetrology - peridotites
DS201112-0397
2011
Jagoutz, O.Gysi, A.P., Jagoutz, O., Schmidt, M.W., Targuisti, K.Petrogenesis of pyroxenites and melt infiltrations in the ultramafic complex of Beni Bousera, northern Morocco.Journal of Petrology, Vol. 52, 9, pp. 1679-1735.Africa, MoroccoMelting, delamination
DS201112-0398
2011
Jagoutz, O.Gysi, A.P., Jagoutz, O., Schmidt, M.W., Targuisti, K.Petrogenesis of pyroxenites and melt infiltrations in the ultramafic complex of Beni Bousera, northern Morocco.Journal of Petrology, Vol. 52, 9, pp. 1679-1735.Africa, MoroccoMetasomatism
DS201312-0433
2013
Jagoutz, O.Jagoutz, O., Schmidt, M.W.The composition of the foundered complement to the continental crust and re-evaluation of fluxes in arcs.Earth and Planetary Science Letters, Vol. 371-372, June pp. 177-190.MantleGeochronology
DS201412-0006
2014
Jagoutz, O.Alvarez-Valero, A.M., Jagoutz, O., Stanley, J., Manthei, C., Ali Moukadiri, A., Piasecki, A.Crustal attenuation as a tracer for the emplacement of the Beni Bousera ultramafic massif ( Betico-Rifean belt).Geological Society of America Bulletin, Vol. 126, no. 11/12, pp. 1614-1624.Africa, MoroccoBeniBoussera
DS201412-0420
2014
Jagoutz, O.Jagoutz, O.Arc crustal differentiation mechanisms.Earth and Planetary Science Letters, Vol. 396, pp. 267-277.MantleGeodynamics
DS201507-0318
2015
Jagoutz, O.Jagoutz, O., Kelemen, P.B.Role of arc processes in the formation of continental crust.Annual Review of Earth and Planetary Sciences, Vol. 43, pp. 363-404.MantleMagmatism
DS201607-1304
2016
Jagoutz, O.Jagoutz, O., Kelemen, P.B.Role of arc progresses in the formation of continental crust.Annual Review of Earth and Planetary Sciences, Vol. 43, pp. 363-404.MantleMagmatism

Abstract: We review data and recent research on arc composition, focusing on the relatively complete arc crustal sections in the Jurassic Talkeetna arc (south central Alaska) and the Cretaceous Kohistan arc (northwest Pakistan), together with seismic data on the lower crust and uppermost mantle. Whereas primitive arc lavas are dominantly basaltic, the Kohistan crust is clearly andesitic and the Talkeetna crust could be andesitic. The andesitic compositions of the two arc sections are within the range of estimates for the major element composition of continental crust. Calculated seismic sections for Kohistan and Talkeetna provide a close match for the thicker parts of the active Izu arc, suggesting that it, too, could have an andesitic bulk composition. Because andesitic crust is buoyant with respect to the underlying mantle, much of this material represents a net addition to continental crust. Production of bulk crust from a parental melt in equilibrium with mantle olivine or pyroxene requires processing of igneous crust, probably via density instabilities. Delamination of dense cumulates from the base of arc crust, foundering into less dense, underlying mantle peridotite, is likely, as supported by geochemical evidence from Talkeetna and Kohistan. Relamination of buoyant, subducting material—during sediment subduction, subduction erosion, arcarc collision, and continental collision—is also likely.
DS201709-2017
2017
Jagoutz, O.Klein, B.Z., Jagoutz, O., Behn, M.D.Archean crustal compositions promote full mantle convection.Earth and Planetary Science Letters, Vol. 474, pp. 516-526.Mantlesubduction

Abstract: Higher mantle potential temperatures characterized the early Earth, resulting in thicker, more mafic oceanic crust entering subduction systems. This change in the composition of subducted slabs, combined with the enhanced temperature contrast between the slab and ambient mantle, would have altered the buoyancy forces driving subduction in the early Earth. Here we investigate this “compositional effect” through a combination of petrologic and thermal modeling. Specifically, we construct density profiles for sinking slabs under modern and early Earth conditions based on a range of mafic crust and mantle compositions. Slab and mantle densities are then determined from mineral assemblages calculated using the thermodynamic modeling program Perple_X along slab geotherms estimated from an analytic thermal model. Consistent with previous studies, we find that modern MORB compositions are typically less dense than the ambient mantle in the basalt barrier zone, located immediately beneath the mantle transition zone. By contrast, possible early Earth oceanic crust compositions are denser than ambient mantle at all depths down to 1000 km. This compositional effect results in slabs that would have more readily penetrated the transition zone, promoting single-layered convection and effective mantle mixing in the early Earth.
DS1992-0764
1992
Jagutz, E.Jacob, D.E., Jagutz, E.Diamondiferous eclogites and mixing of mantle componentsEos Transactions, Vol. 73, No. 14, April 7, supplement abstracts p. 324South AfricaGeochronology, Roberts Victor
DS202107-1095
2021
JAHCoward, S., Campbell, JAHAnalytics for effective investment in early stage diamond exploration. SAIMM Conference, 36 ppts. PdfGlobaleconomics
DS200512-0650
2004
Jah, B.Liu, X., Jah, B., Liu, D., Dong, S., Li, S.SHRIMP U-Pb zircon dating of a metagabbro and eclogites from western Dabie Shan ( Hong'an Block) Chin a and its tectonic implications.Tectonophysics, Vol. 394, 3-4, Dec. 1-, pp. 171-192.ChinaGeochronology, UHP
DS200812-0758
2008
Jahangiri, A.Moayyed, M., Moazzen, M., Calagari, A.A., Jahangiri, A., Modjarrad, M.Geochemistry and petrogenesis of lamprophyric dykes and the associated rocks from Eslamy Peninsula, NW Iran: implications for deep mantle metasomatism.Chemie der Erde, Vol. 68, 2, pp. 141-154.Europe, IranMetasomatism
DS2001-0175
2001
JahnChavagnac, V., Jahn, Villa, Whitehouse, LiuMultichronometric evidence for an in situ origin of the ultra high pressure metamorphic terrane of Dabie Shan.Journal of Geology, Vol. 109, pp. 633-46.Chinaultra high pressure (UHP), Qinling - Dabie orogenic belt
DS1996-0673
1996
Jahn, B.Jahn, B., Comichet, J., Yui, T.F.Ultrahigh epsilon neodymium eclogites from an ultrahigh pressure metamorphic terrane of China.Chemical Geology, Vol. 127, No. 1-3, Jan. 10, pp. 61-80.ChinaEclogites, Metamorphic rocks
DS2000-0959
2000
Jahn, B.Tsai, C-H., Lo C-H, Liou, J.G., Jahn, B.Evidence against subduction related magmatism for the Jiaoziyan gabbro northern Dabie Shan China.Geology, Vol. 28, No. 10, Oct. pp. 943-6.ChinaSubduction, Dabie Shan area
DS2003-0427
2003
Jahn, B.Fu, B., Touret, J.L., Zheng, Y.F., Jahn, B.Fluid inclusions in granulites, granulitized eclogites and garnet pyroxenites from theLithos, Vol. 70, 3-4, pp. 293-319.ChinaUHP, eclogites
DS2003-0641
2003
Jahn, B.Jahn, B., Fan, Q., Yang, J.J., Henin, O.Petrogenesis of the Maowu pyroxenite eclogite body from the UHP metamorphicLithos, Vol. 70, 3-4, pp. 243-67.ChinaUHP, geochronology
DS200412-0587
2003
Jahn, B.Fu, B., Touret, J.L., Zheng, Y.F., Jahn, B.Fluid inclusions in granulites, granulitized eclogites and garnet pyroxenites from the Dabie Sulu terranes, eastern China.Lithos, Vol. 70, 3-4, pp. 293-319.ChinaUHP, eclogites
DS200412-0898
2003
Jahn, B.Jahn, B., Fan, Q., Yang, J.J., Henin, O.Petrogenesis of the Maowu pyroxenite eclogite body from the UHP metamorphic terrane of Dabie Shan: chemical and isotopic constraLithos, Vol. 70, 3-4, pp. 243-67.ChinaUHP, geochronology
DS200512-0473
2005
Jahn, B.Jahn, B., Liu, X., Yui, T.F., Morin, N., Coz, M.B.High pressure/ultrahigh pressure eclogites from the Hongan Block, east central China: geochemical characterization, isotope disequilibrium, geochronologyContributions to Mineralogy and Petrology, Vol. 149, 5, pp. 499-526.Asia, ChinaUHP
DS1995-0865
1995
Jahn, B.M.Jahn, B.M.NCB-SCB: geochemical and isotopic constraints of coesite bearing eclogites from Sulu and Dabie MtnsTerra Nova, Abstract Vol., p. 339.ChinaCoesite, Eclogite
DS1998-0679
1998
Jahn, B.M.Jahn, B.M., Gruau, G., Rudnik, V.A.Archean crustal evolution of the Aldan Shield, Siberia: geochemical and isotopic constraints.Precambrian Research, Vol. 91, No. 3-4, Aug. pp. 333-364.Russia, Siberia, Aldan ShieldGeochronology, Geochemistry
DS1999-0332
1999
Jahn, B.M.Jahn, B.M., Wu, F., Tsai, C.H.Crust mantle interaction induced by deep subduction of the continentalcrust: geochemical and Sr neodymium isotopicChemical Geology, Vol. 157, No. 1-2, May 3, pp. 119-46.ChinaSubduction, ultramafic intrusions, Dabie Mountains
DS1999-0817
1999
Jahn, B.M.Yang, J.J., Jahn, B.M.Sinking intrusion model for the emplacement of garnet bearing peridotites into continent collision orogens...Geology, Vol. 27, No. 8, Aug. pp. 767-8.MantleSubduction, Petrology - peridotites
DS2000-0573
2000
Jahn, B.M.Liou, J.G., Zhang, R.Y., Jahn, B.M.Petrological and geochemical characteristics of ultrahigh pressure metamorphic rocks Dabie Sulu TerraneInternational Geology Review, Vol. 42, No. 4, Apr 1, pp. 328-52.China, East CentralPetrology, geochemistry, ultra high pressure (UHP), Deposit - Dabie Shan area
DS2000-1038
2000
Jahn, B.M.Yang, J.J., Jahn, B.M.Deep subduction of mantle derived garnet peridotites from Su Lu ultra high pressure metamorphic terrane in China.Igc 30th. Brasil, Aug. abstract only 1p.Chinaultra high pressure (UHP) metamorphism
DS200912-0439
2009
Jahn, B.M.Liou, J.G., Ernst, E.G., Zhang, R.Y., Tsujimori, T., Jahn, B.M.Ultrahigh pressure minerals and metamorphic terranes - the view from China.Journal of Asian Earth Sciences, Vol. 35, 3-4, pp. 199-231.ChinaUHP
DS201112-0173
2011
Jahn, B.M.Chauvel, C., Garcon, M., Arndt, N.T., Gallet, S., Jahn, B.M.Average Nd hf isotopic compositions and model age of the upper continental crust.Goldschmidt Conference 2011, abstract p.646.Africa, South AfricaBeach placers
DS1995-0866
1995
Jahn, B-M.Jahn, B-M., Condie, K.C.Evolution of the Kaapvaal Craton viewed from geochem.,samarium-neodymium (Sm-Nd) isotopic analyses intracratonic pelitesGeochimica et Cosmochimica Acta, Vol. 59, No. 11, pp. 2239-58South AfricaGeochronology, Kaapvaal Craton
DS1996-0262
1996
Jahn, B-m.Chavagnac, V., Jahn, B-m.Coesite bearing eclogites from the Bixiling Complex, Dabie Mountains, China: Sm neodymium ages, geochemical....Chemical Geology, Vol. 133, pp. 29-51.ChinaEclogites, coesites, Deposit -Dabie Mountains
DS2001-0525
2001
Jahn, B-M.Jahn, B-M., Caby, R., Monie, P.The oldest ultra high pressure (UHP) eclogites of the world: age of ultra high pressure (UHP) metamorphism, nature of protoliths and tectonic implic.Chemical Geology, Vol. 178, No. 1-4, pp. 143-58.GlobalEclogites, ultra high pressure (UHP), Geochronology
DS2002-0282
2002
Jahn, B-M.Chen, B., Jahn, B-M., Wei, C.Petrogenesis of Mesozoic granitoids in the Dabie UHP Complex, Central China: trace element and Nd Sr isotopeLithos, Vol. 60, No. 1-2, Jan. pp. 67-88.ChinaUltra high pressure, UHP, Geochronology
DS2003-1560
2003
Jahn, B-M.Zheng, Y-F., Yang, J-J., Gong, B., Jahn, B-M.Partial equilibrium of radiogenic and stable isotope systems in garnet peridotite duringAmerican Mineralogist, Vol. 88, pp. 1633-43.ChinaGeochronology, UHP
DS200412-2155
2004
Jahn, B-M.Xie, Z., Zheng, Y-F., Jahn, B-M., Ballevre, M., Chen, J., Gautier, P., Gao, T., Gong, B., Zhou, J.Sm Nd and Rb Sr dating of pyroxene garnetite from North Dabie in east centra China: problem of isotope disequilibrium due to retChemical Geology, Vol. 206, 1-2, May 28, pp. 137-158.ChinaUHP, eclogite, geochronology
DS200412-2227
2003
Jahn, B-M.Zheng, Y-F., Yang, J-J., Gong, B., Jahn, B-M.Partial equilibrium of radiogenic and stable isotope systems in garnet peridotite during ultrahigh pressure metamorphism.American Mineralogist, Vol. 88, pp. 1633-43.ChinaGeochronology, UHP, Shimafang, Sulu
DS200512-0474
2005
Jahn, B-M.Jahn, B-M., Liu, X., Yui, T-F., Morin, N., Bouhnik-Le Coz, M.High pressure ultrahigh pressure eclogites from the Hong an Block, east central China: geochemical characterization, isotope disequilibrium and geochronological controversy.Contributions to Mineralogy and Petrology, On lineChinaUHP
DS200512-0644
2005
Jahn, B-M.Lin,L.H., Wang, P-L., Lo, C-H., Tsai, C-H., Jahn, B-M.40 Ar 39 Ar thermochronological constraints on the exhumation of ultrahigh pressure metamorphic rocks in the Sulu Terrane of eastern China.International Geology Review, Vol. 47, 7, pp. 872-886.Asia, ChinaUHP
DS200512-1246
2004
Jahn, B-M.Zhang, R.Y., Liou, J.G., Yang, J.S., Liu, L., Jahn, B-M.Garnet peridotites in the UHP Mountain Belts of China.International Geology Review, Vol. 46, 11, pp. 981-1004.China, AsiaUHP
DS200612-1242
2006
Jahn, B-M.Schneider, J., Jahn, B-M., Okamoto, K., Tong, L., Lizuka, Y., Xu, Z.Rb Sr and Sm Nd isotope analyses of CCSD eclogites ( Sulu, China): a test for the closure temperature concept.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 12, abstract only.ChinaUHP, geochronology
DS200712-0479
2007
Jahn, B-m.Jahn, B-m., Chen, B.Dabie Shan UHP metamorphic terrane: Sr Nd Pb isotopic constraint to pre-metamorphic subduction polarity.International Geology Review, Vol. 49, 1, pp. 14-29.ChinaUHP
DS201012-0455
2010
Jahn, B-M.Liu, X., Jahn, B-M., Lou, Y.Diachronous subduction and exhumation of the Tongbai Dabie Sulu HP/UHP metamorphic belt in central China.Goldschmidt 2010 abstracts, posterChinaUHP
DS201112-1053
2011
Jahn, B-M.Tong, L., Jahn, B-M., Zheng, Y-F.Diverse P-T paths of the northern Dabie complex in central Chin a and its reworking in the early Cretaceous.Journal of Asian Earth Sciences, Vol. 42, 4, pp. 633-640.Asia, ChinaUHP
DS201312-0512
2013
Jahn, B-M.Kovach, V.,Salnikova, E., Wang, K-L., Jahn, B-M., Chiu, H-Y., Reznitskiy, L., Kotov, A., Lizuka, Y., Chung, S-L.Zircon ages and Hf isotopic constraints on sources of clastic metasediments of the Slyudyansky high grade complex, southeastern Siberia: implication for continental growth and evolution of the Central Asian orogenic belt.Journal of Asian Earth Sciences, Vol. 62, pp. 18-36.Russia, SiberiaUHP, Geochronology
DS200712-0480
2007
Jahn, S.Jahn, S., Madden, P.A.Modeling Earth materials from crustal to lower mantle conditions: a transferable set of interaction potentials for the CMAS system.Physics of the Earth and Planetary Interiors, Vol. 162, 1-2, pp. 129-139.MantleChemistry
DS200712-0481
2007
Jahn, S.Jahn, S., Madden, P.A.Modeling Earth materials from crustal to lower mantle conditions: a transferable set of interaction potentials for the CMAS system.Physics of the Earth and Planetary Interiors, Vol. 162, 1-2, pp. 129-139.MantleChemistry
DS201212-0278
2012
Jahn, S.Haigis, V., Salanne, M., Jahn, S.Thermal conductivity of minerals in the Earth's lower mantle from molecular dynamics.emc2012 @ uni-frankfurt.de, 1p. AbstractMantleGeothermometry
DS201212-0279
2012
Jahn, S.Haigis, V., Salanne, M., Jahn, S.Thermal conductivity of MgO, MgSiO3 perovskite and post-perovskite in the Earth's deep mantle.Earth and Planetary Science Letters, Vol. 355-356, pp. 102-108.MantleGeothermometry
DS202105-0776
2021
Jahn, S.Martirosyan, N.S., Efthimiopoulos, I., Pennacchioni, L., Wirth, R., Jahn, S., Koch-Muller, M.Effect of catonic substitution on the pressure -induced phase transition in calcium carbonate.American Mineralogist, Vol. 106, pp. 549-558. pdfMantledeep carbon cycle
DS1995-0867
1995
Jahne, B.Jahne, B.Digital image processing.Springer, 396p. approx. $ 75.00GlobalBook -ad, Image processing
DS1940-0183
1948
Jahns, R.H.Jahns, R.H.The Gem Deposits of Southern CaliforniaEng. Sci. Monthly; Gems And Gemology, Vol. 11, No. 2, PP. 6-9; Vol. 6, PP. 6-9, 28, 30.United States, California, West CoastBlank
DS1960-0058
1960
Jahns, R.H.Jahns, R.H.Gem Stones and Allied MineralsIn: Industrial Minerals And Rocks, American Institute of Mining, Metallurgical, And Petroleum Engineers (aime), PP. 383-441.South Africa, Southwest Africa, GlobalDiamonds, Production, Figures
DS1960-0059
1960
Jahns, R.H.Jahns, R.H.Precious Stones (1960)Industrial Minerals And Rocks, American Institute of Mining, PP. 383-441.United States, CanadaBlank
DS2002-0759
2002
Jahren, A.H.Jahren, A.H.The biogeochemical consequences of the mid-Cretaceous superplumeJournal of Geodynamics, Vol.34,2, Sept. pp. 163-76.GlobalBiogeochemistry, Mantle plumes, hot spots
DS1996-0674
1996
Jaillard, E.Jaillard, E., Soler, P.Cretaceous to early Paleocene tectonic evolution of the northern Central Andes 0-10 and its relations geodynaM.Tectonophysics, Vol. 259, No. 1-3, June 30, pp. 41-54Andes, Cordillera, Bolivia, ArgentinaGeodynamics, Tectonics
DS2002-0760
2002
Jaillard, E.Jaillard, E., Herail, G., Monfret, T., Worner, G.Andean geodynamics: main issues and contributions from the 4th. ISAGTectonophysics, Vol.345, 1-4, Feb.15, pp. 1-15.AndesGeodynamics - brief review
DS2001-0424
2001
Jaillard, Yepes et al.Guililer, B., Chatelain, J.L., Jaillard, Yepes et al.Seismological evidence on the geometry of the orogenic system in central northern Ecuador.Geophysical Research Letters, Vol. 28, No. 19, Oct. 1, pp. 3749-52.Ecuador, South AmericaGeophysics - seismics, Tectonics
DS1999-0018
1999
Jaillard. E.Arculus, R.J., Lapierre, H., Jaillard. E.Geochemical window into subduction and accretion processes: Raspas metamorphic complex, Ecuador.Geology, Vol. 27, No. 6, June, pp. 547-50.EcuadorLithosphere, subduction, Geochemistry - Raspas
DS1988-0324
1988
JainJain, Ajai Kumar, Tapi, R.D.Study of carbonatite in the northeast of BarwahDistrict, Khargone, SOURCE[ Vijana Parshad Anusandhan Patrike, (Ind)Vijana Parshad Anusandhan Patrike, (Ind), Vol. 31, No. 2-3, June pp. 89-96IndiaCarbonatite
DS1995-0385
1995
Jain, A.K.Das, J.D. , saraf, A.K., Jain, A.K.Fault tectonics of the Shilong plateau and adjoining regions, north-east India using remote sensing dataInternational Journal of Remote Sensing, Vol. 16, No. 9, June pp. 1633-46IndiaRemote Sensing, Tectonics
DS202005-0730
2020
Jain, A.K.Fareeduddin., Pant, N.C., Gupta, S., Chakraborty, P., Sensarma, S., Jain, A.K., Prasad, G.V.R., Srivastava, P., Rjan, S., Tiwari, V.M.The geodynamic evolution of the Indian subcontinent - an introduction.Episodes ( IUGS), Vol. 43, 1, pp. 1-18.Indiacarbonatite
DS202009-1627
2020
Jain, A.K.Fareeduddin, Pant, N.C., Gupta, S., Chakraborty, P., Sensarma, S., Jain, A.K., Prasad, G.V.R., Srivastava, P., Rajan, S., Tiwari, V.M.The geodynamic evolution of the Indian subcontinent - an introduction.Episodes, Vol. 43, 1, pp. 8p.Indiacarbonatites
DS1982-0295
1982
Jain, B.K.Jain, B.K., Regan, R.D.Integration of Satellite and Conventional Geophysical Dat a with tectonics and Structural Information Over the African Continent.Geoexploration., Vol. 20, No. 3-4, PP. 233-258.Africa, West Africa, Central Africa, East Africa, Southwest AfricaStructure, Tectonics, Remote Sensing
DS201706-1102
2017
Jain, C.Rozel, A.B., Golabek, G.J., Jain, C., Tackley, P.J., Gerya, T.Continental crust formation on early Earth controlled by intrusive magmatism.Nature, online availableMantlegeodynamics

Abstract: The global geodynamic regime of early Earth, which operated before the onset of plate tectonics, remains contentious. As geological and geochemical data suggest hotter Archean mantle temperature1, 2 and more intense juvenile magmatism than in the present-day Earth3, 4, two crust-mantle interaction modes differing in melt eruption efficiency have been proposed: the Io-like heat-pipe tectonics regime dominated by volcanism5, 6 and the “Plutonic squishy lid” tectonics regime governed by intrusive magmatism, which is thought to apply to the dynamics of Venus7, 8, 9. Both tectonics regimes are capable of producing primordial tonalite-trondhjemite-granodiorite (TTG) continental crust5, 10 but lithospheric geotherms and crust production rates as well as proportions of various TTG compositions differ greatly9, 10, which implies that the heat-pipe and Plutonic squishy lid hypotheses can be tested using natural data11. Here we investigate the creation of primordial TTG-like continental crust using self-consistent numerical models of global thermochemical convection associated with magmatic processes. We show that the volcanism-dominated heat-pipe tectonics model results in cold crustal geotherms and is not able to produce Earth-like primordial continental crust. In contrast, the Plutonic squishy lid tectonics regime dominated by intrusive magmatism results in hotter crustal geotherms and is capable of reproducing the observed proportions of various TTG rocks. Using a systematic parameter study, we show that the typical modern eruption efficiency of less than 40 per cent12 leads to the production of the expected amounts of the three main primordial crustal compositions previously reported from field data4, 11 (low-, medium- and high-pressure TTG). Our study thus suggests that the pre-plate-tectonics Archean Earth operated globally in the Plutonic squishy lid regime rather than in an Io-like heat-pipe regime.
DS201905-1047
2019
Jain, C.Jain, C., Rozel, A.B., Tackley, P.J.Quantifying the correlation between mobile continents and elevated temperatures in the subcontinental mantle.Geochemistry, Geophysics, Geosystems, Vol. 20, 3, pp. 1358-1386.Mantlegeothermometry

Abstract: Continents influence the mantle's convective wavelength and the heat flow escaping from the planet's surface. Over the last few decades, many numerical and analytical studies have contributed to the debate about whether the continents can warm up the subcontinental mantle or not and if they do, then to what extent? However, a consensus regarding the exact nature and magnitude of this correlation between continents and elevated temperatures in the subcontinental mantle remains to be achieved. By conducting a systematic parameter study using 2?D global mantle convection simulations with mobile continents, we provide qualitative and quantitative observations on the nature of this correlation. In our incompressible and compressible convection models, we observe the general processes of downwellings bringing cold material into the mantle along continental margins and a subsequent buildup of warm thermal anomalies underneath the continents. We compute the amplitude and degree of this correlation using spectral decomposition of the temperature and composition fields. The dominant degree of correlation evolves with time and changes with continental configuration. Using simple empirical fits, we observe that this correlation decreases with increasing core temperature, number of continents, internal heating, or decreasing reference viscosity. We also report simple regressions of the time dependence of this correlation. Additionally, we show that decompression melting as a result of a mantle upwelling or small?scale sublithospheric convection leads to voluminous volcanism. The emplacement of this dense basalt?eclogite material breaks the continents apart and destroys the correlation.
DS201908-1780
2019
Jain, C.Jain, C., Rozel, A.B., Tackley, P.J., Sanan, P., Gerya, T.V.Growing primordial continental crust self-consistently in global mantle convection models.Gondwana Research, Vol. 73, pp. 96-122.Mantlegeothermometry

Abstract: The majority of continental crust formed during the hotter Archean was composed of Tonalite-Trondhjemite-Granodiorite (TTG) rocks. In contrast to the present-day loci of crust formation around subduction zones and intra-plate tectonic settings, TTGs are formed when hydrated basalt melts at garnet-amphibolite, granulite or eclogite facies conditions. Generating continental crust requires a two step differentiation process. Basaltic magma is extracted from the pyrolytic mantle, is hydrated, and then partially melts to form continental crust. Here, we parameterise the melt production and melt extraction processes and show self-consistent generation of primordial continental crust using evolutionary thermochemical mantle convection models. To study the growth of TTG and the geodynamic regime of early Earth, we systematically vary the ratio of intrusive (plutonic) and eruptive (volcanic) magmatism, initial core temperature, and internal friction coefficient. As the amount of TTG that can be extracted from the basalt (or basalt-to-TTG production efficiency) is not known, we also test two different values in our simulations, thereby limiting TTG mass to 10% or 50% of basalt mass. For simulations with lower basalt-to-TTG production efficiency, the volume of TTG crust produced is in agreement with net crustal growth models but overall crustal (basaltic and TTG) composition stays more mafic than expected from geochemical data. With higher production efficiency, abundant TTG crust is produced, with a production rate far exceeding typical net crustal growth models but the felsic to mafic crustal ratio follows the expected trend. These modelling results indicate that (i) early Earth exhibited a "plutonic squishy lid" or vertical-tectonics geodynamic regime, (ii) present-day slab-driven subduction was not necessary for the production of early continental crust, and (iii) the Archean Earth was dominated by intrusive magmatism as opposed to "heat-pipe" eruptive magmatism.
DS1995-0526
1995
Jain, J.C.Fedorowich, J.S., Jain, J.C., Kerrich, R., Sopuck, V.Trace element analysis of garnet by laser-ablation microprobe ICP-MS....pyrope garnet.Canadian Mineralogist, Vol. 33, No. 2, April pp. 469-480.Wyoming, South AfricaGarnet -mass spectrometry, Deposit -Schaffer, Frank Smith
DS200912-0332
2009
Jain, P.K.Jain, P.K.Mineral royalty in India and its comparison with selected countries.Minerals & Energy - Raw Materials Report, Vol. 23, 3, pp. 119-126.IndiaLegal
DS1975-0585
1977
Jain, R.S.Nautiyal, S.P., Jain, R.S.On the Prospect of Locating New Diamondiferous Areas in IndiIndia Geological Survey Records, Vol. 108, PT. 2, PP. 157-166.IndiaDiamond Occurrences, Prospecting
DS1991-0784
1991
Jaireth, S.Jaireth, S., Sen, A.K., Varma, O.P.Fluid inclusion studies in apatite of the Sung Valley carbonatite northeast India: evidence of melt-fluid immiscibilityJournal of Geological Society India, Vol. 37, June pp. 547-559IndiaCarbonatite, Geochemistry
DS201412-0422
2014
Jaireth, S.Jaireth, S., Hoatson, D.M., Miezitis, Y.Geological setting and resources of the major rare-earth-element deposits in Australia.Ore Geology Reviews, Vol. 61, pp. 72-128.AustraliaREE in alkaline rocks
DS1998-1454
1998
Jakimowicz, J.Taylor, W.R., Reddicliffe, T.H., Jakimowicz, J.Thermobarometry of peridotitic chromium diopside from the Merlin kimberlites -nature of upper mantle..7th International Kimberlite Conference Abstract, pp. 899-901.AustraliaProterozoic, craton, Deposit - Merlin
DS2003-1146
2003
Jakimowicz, J.Reddicliffe, T.H., Jakimowicz, J., Hell, A.J., Robins, J.A.The geology, mineralogy and near surface chacteristics of the Ashmore and Seppelt8ikc, Www.venuewest.com/8ikc/program.htm, Session 1 POSTER abstractAustraliaKimberlite geology and economics, Deposit - Ashmore, Seppelt
DS200912-0489
2009
Jakimowicz, J.McInnes, B.I.A., Evans, N.J., McDonald, B.J., Kinny, P.D., Jakimowicz, J.Zircon U Th Pb He double dating of the Merlin kimberlite field, Northern Territory, Australia.Lithos, In press availableAustraliaDeposit - Merlin
DS201412-0940
2014
Jakins, A.Van der Westhuyzen, P., Bouwer, W., Jakins, A.Current trends in the development of new or optimization of existing diamond processing plants, with focus on beneficiation.South African Institute of Mining and Metallurgy, Vol. 114, July pp. 537-546.TechnologyDiamond processing plants
DS202007-1158
2020
Jakkawanvibul, J.Leelawatanasuk, T., Atichat, W., Pisutha-Arnond, V., Sutthirat, C., Jakkawanvibul, J., GITTwo decades of GIT's ruby and sapphire color standards.incolorMagazine.com, Vol. winter pp. 96-103.Asia, Thailandsapphire colour
DS1996-0675
1996
Jakni, B.Jakni, B., Dautria, J-M., Liotard, J-M., Brigueu, L.Evidence of the presence of a carbonated mantle beneath Bas-Languedoc:peridotitic xenoliths Grand Magnon...C.r. Academy Of Science Paris., *french, Vol. 323, iia, pp. 33-40.FranceXenoliths, Basanites, Leucito-nephelinites
DS1975-1045
1979
Jakob, W.K.O.Gurney, J.J., Jakob, W.K.O., Dawson, J.B.Metacrysts from the Monastery Kimberlite PipeProceedings of Second International Kimberlite Conference, Proceedings Vol. 2, PP. 227-243.South AfricaPetrography
DS1975-0539
1977
Jakob, W.R.O.Jakob, W.R.O.Geochemical Aspects of the Megacryst Suite from the Monastery Kimberlite Pipe.Cape Town: Msc. Thesis, University Cape Town., 81P.South AfricaGeochemistry
DS1996-1132
1996
Jakobsen, R.Postma, D., Jakobsen, R.Redox zonation: equilibrium constraints on the iron (III) SO4 reductioninterface.Geochimica et Cosmochimica Acta, Vol. 60, No. 17, pp. 3169-75.GlobalGeochemistry - redox not specific to diamonds
DS200812-0514
2008
Jakobsson, S.Jakobsson, S., Holloway, J.R.Mantle melting in equilibrium with an iron wustite.. graphite buffered COH fluid.Contributions to Mineralogy and Petrology, Vol. 155, 2, pp. 247-256.MantleMelting
DS1994-0922
1994
Jakop, Z.J.Kjarsgaard, B.A., Spark, R.N., Jakop, Z.J.Preliminary geology Kaola 76D/10Geological Survey of Canada (GSC) Open File, No. 2966, map, 1: 50, 000Northwest TerritoriesGeology
DS1994-0923
1994
Jakop, Z.J.Kjarsgaard, B.A., Spark, R.N., Jakop, Z.J.Geology, Ursula Lake 76D/16Geological Survey of Canada (GSC) Open File, No. 2967, map, 1: 50, 000Northwest TerritoriesGeology
DS1994-0924
1994
Jakop, Z.J.Kjarsgaard, B.A., Spark, R.N., Jakop, Z.J.Preliminary geology Koala District of MackenzieGeological Survey of Canada Open file Map., No. 2966, 1: 50, 000 $ 19.75Northwest TerritoriesGeology map, Koala area
DS1994-0925
1994
Jakop, Z.J.Kjarsgaard, B.A., Spark, R.N., Jakop, Z.J.Preliminary geology Ursula Lake District of MackenzieGeological Survey of Canada Open file Map., No. 2967, 1: 50, 000 $ 19.75Northwest TerritoriesGeology map, Ursula Lake area
DS1995-0868
1995
Jakop, Z.J.Jakop, Z.J.Petrology and heavy mineral concentrate analysis of kimberlites, GuigueTownship, determination-economicCarleton University, BSc. Thesis, 75p.QuebecPetrology, Deposit -Guigue
DS1999-0364
1999
Jakop, Z.J.Kjarsgaard, B.A., Jakop, Z.J., Spark, R.N.Preliminary geology, Exeter Lake 76D/15Geological Survey of Canada (GSC) Open File, No. 3702, map, 1: 50, 000Northwest TerritoriesGeology
DS200512-0541
2005
Jakop, Z.J.Kjarsgaard, B.A., Spark, R.N., Jakop, Z.J.Preliminary geology Koala district of Mackenzie Northwest Territories. Map 76 D 10.Geological Survey of Canada Open File, OF 2966 $ 21.00Canada, Northwest TerritoriesGeology map
DS200512-0542
2005
Jakop, Z.J.Kjarsgaard, B.A., Spark, R.N., Jakop, Z.J.Preliminary geology Ursula Lake district of Mackenzie Northwest Territories. Map 76 D 16.Geological Survey of Canada Open File, OF 2967 $ 21.00Canada, Northwest TerritoriesGeology map
DS201212-0336
2012
Jakovlev, A.V.Jakovlev, A.V., Bushenkova, N.A., Koulakov, I.yu., Dobretsov, N.L.Structure of the upper mantle in the circum-artic region from regional seismic tomography.Russian Geology and Geophysics, Vol. 53, 10. pp. 963-971.RussiaGeophysics - seismic
DS200412-0899
2004
Jakubec, C.Jakubec, C.From exploration geology to mine design.PDAC 2004, 1p. abtract.GlobalMine risk
DS1995-0869
1995
Jakubec, J.Jakubec, J., Milton, A., Siwawa, C.Z., Struik, M.J.P.M.Improvement in blasting techniques at Orapa and Letlhakane diamond Mines -a holistic approach.African Mining 95, Institute of Mining and Metallurgy (IMM) Publishing, pp. 285-304.BotswanaMining, Deposit -Orapa and Letlhakane
DS2003-0642
2003
Jakubec, J.Jakubec, J.Role of geology in project development8 Ikc Www.venuewest.com/8ikc/program.htm, Session 1, AbstractNorthwest TerritoriesPipe emplacement, Deposit - Ekati
DS2003-0643
2003
Jakubec, J.Jakubec, J., Long, L.Underground geotechnical and geological investigation at Ekati diamond mine - Koala8ikc, Www.venuewest.com/8ikc/program.htm, Session 1 POSTER abstractNorthwest TerritoriesKimberlite geology and economics, Deposit - Koalo North
DS200412-0900
2003
Jakubec, J.Jakubec, J.Role of geology in project development.8 IKC Program, Session 1, AbstractCanada, Northwest TerritoriesPipe emplacement Deposit - Ekati
DS200612-0634
2006
Jakubec, J.Jakubec, J.Diamond project management - a holistic approach.CIM Conference and Exhibition, Vancouver - Creating Value with Values, List of talks CIM Magazine, Feb. p. 77.GlobalMining
DS200612-0635
2006
Jakubec, J.Jakubec, J.Kimberlite emplacement model - impact on diamond project development.Emplacement Workshop held September, 5p. extended abstractGlobalMining issues, pipe geometry, Country rock, dilution
DS200812-0515
2008
Jakubec, J.Jakubec, J.Kimberlite emplacement models - the implications for mining projects.Journal of Volcanology and Geothermal Research, Vol. 174, 1-3, pp. 20-28.GlobalEmplacement models, diamond mining
DS201503-0151
2015
Jakubec, J.Jakubec, J., Johnson, M.The Jericho diamond mine - what happened?Vancouver Kimberlite Cluster, Feb. 20, 1p. AbstractCanada, NunavutDeposit - Jericho
DS201708-1678
2017
Jakubec, J.Jakubec, J.Mining for diamonds - history and present.11th. International Kimberlite Conference, OralGlobalBlank
DS201708-1679
2017
Jakubec, J.Jakubec, J.Underground diamond mining at Ekati and Diavik mines.11th. International Kimberlite Conference, PosterCanada, Northwest Territoriesdeposit - Ekati, Diavik
DS202202-0193
2021
Jakubek, R.S.Goodrich, C.A., Nestola, F., Jakubek, R.S.Diamonds in ureilites: the never ending story.Cosmo Elements, 10.2138/gselements.17.4.292 2p. PdfCosmosUreilites
DS201709-2020
2017
JakubovaKotova, J., Fedortchouk, Y., Wirth, R., Whitehouse, M., JakubovaUHP-UHT melting and diamond formation. MicrodiamondsGoldschmidt Conference, abstract 1p.MantleUHP

Abstract: Exhumed ultrahigh-pressure (UHP) terranes, involving slices of deeply subducted crustal rocks, provide unique material for studying material transfer in subduction zones. Diamond-bearing UHP rocks with sedimentary protoliths allow for tracing melting processes at both UHP and UHT including carbon cycling in the Earth. We studied microdiamonds and associated phases in two contrasting lithologies, (1) acid, quartzofeldpathic UHP gneiss composed of garnet, kyanite, feldspar, quartz and biotite, with a high ASI characteristic of sedimentary rocks, and (2) intermediate garnet-clinopyroxene rock containing quartz, feldspar, minor kyanite and biotite, which is metaluminous. Whereas rock (1) contains exclusively single octahedral diamonds with perfect crystal shape in garnet, kyanite (more common) and zircon, the microdiamonds in the rock (2) occur mostly as clusters of cuboid shape in garnet and zircon. Micro-Raman and FIB TEM data document presence of graphite, quartz and rutile at diamond/host interface or in separate multiple solid inclusions (MSI) whereas carbonates are practically absent. The morphology and lack of inclusions reflect relatively slow growth of the octahedral diamonds (rock 1) at lower fluid supersaturation. Individual deep and symmetrical negative trigons (AFM) on the (111) plane suggest dissolution by a residual silicate-carbonate melt. In contrast, polycrystallline character of diamond cuboids (rock 2) along with their common dissolution and formation of numerous tetragonal etch pits reflect relatively rapid growth of these grains from highly supersaturated fluid/melt. Peak P-T conditions for the UHP rocks of ? 1100ºC at 4.5 GPa are located above the phengite dehydration melting curve, where silicate melts are produced and may coexist with carbonate melts. In view of the light carbon isotope composition and lack of carbonates, we suggest that the diamonds crystallized from the graphitized primordial organic matter under reducing conditions at presence of silicate melt.
DS201612-2312
2016
Jakubova, P.Kotkova, J., Fedortchouk, Y., Jakubova, P., Whitehouse, M., Wirth, R.Bohemian microdiamonds: diamond forming media and carbon source.Acta Geologica Sinica, Vol. 90, 1, July abstract P. 217-219.EuropeMicrodiamonds
DS201112-0474
2011
Jakusconek, T.Jakusconek, T.Rough times behind - sparkle ahead. Harry Winston featured and recommended.Scotia Capital Equity Research Report, June 29, 38p.Canada, Northwest Territories, GlobalNews item - Harry Winston
DS201312-0434
2013
Jakusconek, T.Jakusconek, T., et al.Diamond Quarterly Review: The carat chronicles Q1/13.Scotia Capital Equity Research Report, 36p.GlobalReview of companies
DS1989-0697
1989
Jalahi, S.Jalahi, S.Diamond - with a color change garnet inclusionGems and Gemology - Gem Trade Lab Notes, Vol. 25, No. 4, Winter pp. 237-238GlobalDiamond morphology, Diamond inclusion
DS201903-0548
2019
Jalowitski, T.Vieira Conceicao, R., Colombo Carniel, L., Jalowitski, T., Gervasoni, F., Grings Cedeno, D.Geochemistry and geodynamic implications on the source of Parana-Etendeka Large Igneous Province evidenced by the late 128 Ma Rosario-6 kimberlite, southern Brazil.Lithos, Vol. 328-329, pp. 130-145.South America, Brazildeposit - Rosario-6

Abstract: The Rosário-6 is a non-diamondiferous hypabyssal kimberlite located above the Rio de la Plata craton and near the south-eastern edge of the Paraná Basin, in southern Brazil. It is petrographically an inequigranular texture, macrocrystal kimberlite, fresh and the groundmass exhibits a microporphyritic texture and round megacrysts of olivine, which are derived from disaggregated mantle xenoliths. Olivine is also present as macrocrysts, microphenocrysts and in the groundmass together with phlogopite and apatite. These microphenocrysts are immersed in a groundmass of olivine, monticellite, phlogopite, CaTiO3-perovskite, apatite, Mg-chromite and Mg-ulvöspinel and melilite. A mesostasis assemblage of phlogopite, melilite, soda melilite, akermanite and calcium carbonate is segregated from the groundmass. Its geochemical signature is similar to those of transitional kimberlites of Kaapvaal Craton, South Africa, and the U-Pb ages of ~ 128 Ma on perovskite reveal that Rosário-6 kimberlite post-dates the main pulse of volcanism in the Paraná-Etendeka Large Igneous Province (LIP). The high Ti content of some minerals, such as Mg-chromite, Mg-ulvöspinel, phlogopite and melilite, and the presence of perovskite suggest a Ti-rich source. The petrographic, geochemical and isotopic data indicate that the Rosário-6 kimberlite source is a depleted mantle metasomatized by H2O-rich fluids, CO2-rich and silicate melts derived from the recycling of an ancient subducted oceanic plate (eclogite) before the South Atlantic opening. Although several authors indicate the influence of Tristan da Cunha plume for the generation of alkaline magmatism associated to the Paraná-Etendeka flood basalts, our data demonstrates that Tristan da Cunha plume has no chemical contribution to the generation of Rosário-6 kimberlite, except by its thermal influence.
DS202008-1402
2020
Jalowitzki, T.Jalowitzki, T., Gervasoni, F., Sumino, H., Klemme, S., Berndt, J., Dalla Costa, M., Fuck, R.A.Plume subduction events recorded by KS2 kimberlite indicator minerals from Juina, Brazil.Goldschmidt 2020, 1p. AbstractSouth America, Brazil, Mato Grossodeposit - Juina

Abstract: The Cretaceous Juína Kimberlite Province (JKP, 95-92 Ma) is located in the southwest of the Amazonian Craton, northwest of Mato Grosso, Brazil. Here we present new geochemical and isotopic data of garnet (n=187) and zircon (n=25) megacrysts collected from the KS2 kimberlite. The magmatic zircon megacrysts have U-Pb ages of 92.1 ± 0.7 Ma. The chondrite-normalized rare earth element (REE) patterns (LREE
DS202101-0002
2020
Jalowitzki, T.Carniel, L.C., Conceicao, R.V., Klemme, S., Berndt,J., Jalowitzki, T.Origin and redox conditions of the Rosario-6 alnoite of southern Brazil: implications for the state of the mantle during Gondwana breakup.Lithos, Vol. 376-377, 105751, 13p. PdfSouth America, Brazildeposit - Rosario do Sul

Abstract: The Rosário-6 alnöite is an alkaline occurrence that belongs to the Rosário do Sul kimberlitic field, situated in the south-eastern edge of the Paraná Basin, in the South of Brazil, and erupted concomitant or just after the volcanism of the Paraná-Etendeka Large Igneous Province (LIP). Following recent published nomenclature, Rosário-6 was classified as a kimberlite from a deep mantle source with a distinctive inequigranular texture resulting from the presence of olivine macrocrysts set in a finer-grained matrix. Trace element compositions of olivine, monticellite, spinel, phlogopite, perovskite and apatite show an enrichment of Nb, Ce, Ta and U, which implies that the Rosário-6 mantle source was enriched by recycled oceanic crust. The positive anomalies of Rb, Ba and Sr, the enrichment in LREE, and the negative anomalies of HREE in the Rosário-6 minerals, are indicative of a metasomatic process in the mantle source that could be caused by fluids from recycled oceanic crust. Temperature, pressure and redox conditions (fO2) of Rosário-6 crystallization are estimated from olivine, spinel, perovskite and monticellite compositions: Rosário-6 crystallization temperatures using olivine-spinel geothermobarometry were around 1390(±56)°C at a pressure of 2 GPa, and 1405(±56)°C at 3 GPa with ?NNO = 2.8, at pressures constrained by the silica activity limited by the crystallization of monticellite. Using a perovskite oxybarometer, we obtained a larger range of ?NNO (from -2.8 to 3.4), whereas the monticellite oxybarometer results in fO2 of -2.6 to -0.8 ?NNO units. The fO2 indicate that the mantle source of Rosário-6 at the time of crystallization was possibly oxidized by materials from ancient subduction, which may be the cause for Rosário-6's low potential to carry and preserve diamonds. Horizontal tomographic images derived from P-wave velocity data constrain the thickness of the lithosphere in this region and the overall information indicates that mantle cooling at depths below 200 km may have resulted of an accumulation of oceanic plate slabs from old subduction. The geochemical data in conjunction with the geophysical characterizes the conditions of Rosário-6 mineral crystallization and also the mantle of this part of South America during Gondwana breakup.
DS202109-1458
2021
Jalowitzki, T.de Caravlho, L.D.V., Jalowitzki, T., Scholz, R., de Oliveira Gonzales, G., Rocha, M.P., Peeira, R.S., Lana, C., de Castro, P., Queiroga, G., Fuck, R.A.An exotic Cretaceous kimberlite linked to metasomatized lithospheric mantle beneath the southwestern margin of the Sao Francisco Craton, Brazil.Geoscience Frontiers, doi,org/101016/j.gsf.2021.101.28South America, Brazildeposit - Osvaldo Franca 1

Abstract: We present major and trace element compositions of mineral concentrates comprising garnet xenocrysts, ilmenite, phlogopite, spinel, zircon, and uncommon minerals (titanite, calzirtite, anatase, baddeleyite and pyrochlore) of a newly discovered Late Cretaceous kimberlite (U-Pb zircon age 90.0 ± 1.3 Ma; 2?) named Osvaldo França 1, located in the Alto Paranaíba Igneous Province (APIP), southeastern Brazil. Pyrope grains are lherzolitic (Lherz-1, Lherz-2 and Lherz-3), harzburgitic (Harz-3) and wehrlitic (Wehr-2). The pyrope xenocrysts cover a wide mantle column in the subcratonic lithosphere (66-143 km; 20-43 kbar) at relatively low temperatures (811-875 °C). The shallowest part of this mantle is represented by Lherz-1 pyropes (20-32 kbar), which have low-Cr (Cr2O3 = 1.74-6.89 wt.%) and fractionated middle to heavy rare earth elements (MREE-HREE) pattern. The deepest samples are represented by Lherz-2, Lherz-3, Harz-3, and Wehr-2 pyropes (36-43 kbar). They contain high-Cr contents (Cr2O3 = 7.36-11.19 wt.%) and are characterized by sinusoidal (Lherz-2 and Wehr-2) and spoon-like (Lherz-3 and Harz-3) REE patterns. According to their REE and trace elements, pyrope xenocrysts have enriched nature (e.g., Ce and Yb vs. Cr2O3), indicating that the cratonic lithosphere has been affected by a silicate melt with subalkaline/tholeiite composition due to their low Zr, Ti and Y concentrations. Besides minerals with typical kimberlitic signatures, such as ilmenite and zircon, the exotic compositions of phlogopite and ulvöspinel suggest an enriched component in the magma source. The formation of rare mineral phases with strong enrichment of light-REE (LREE) and high field strength elements (HFSE) is attributed to the late-stage kimberlitic melt. We propose a tectonic model where a thermal anomaly, represented by the low-velocity seismic anomaly observed in P-wave seismic tomography images, supplied heat to activate the alkaline magmatism from a metasomatized cratonic mantle source during the late-stages of Gondwana fragmentation and consequent South Atlantic Ocean opening. The metasomatism recorded by mineral phases is a product of long-lived recycling of subducted oceanic plates since the Neoproterozoic (Brasiliano Orogeny) or even older collisional events, contributing to the exotic character of the Osvaldo França 1 kimberlite, as well as to the cratonic lithospheric mantle.
DS201705-0821
2017
Jamal, D.L.Chauque, F.R., Cordani, U.G., Jamal, D.L., Onoe, A.T.The Zimbabwe Craton in Mozambique: a brief review of its geochronological pattern and its relation to the Mozambique Belt.Journal of African Earth Sciences, Vol. 129, pp. 366-379.Africa, MozambiqueCraton, Zimbabwe

Abstract: The eastern margin of the Zimbabwe Craton, along the Mozambique-Zimbabwe border, includes the oldest rocks of west-central Mozambique constituting a large terrain of granite-greenstone type dated between 3000 and 2500 Ma. These rocks consist mainly of gneisses and granitoid rocks of tonalitic-trondhjemitic-granodioritic composition belonging to the Mudzi Metamorphic Complex in the northern part and to the Mavonde Complex in the southern part. The latter is associated with a granite-greenstone terrain, which includes the eastern part of Mutare-Odzi-Manica greenstone belt. A volcano-sedimentary sequences cover, belonging to the apparently Mesoproterozoic and Paleoproterozoic Umkondo and Gairezi groups respectively was deposited along the eastern margin of the craton and is exposed in the territory of Mozambique. The Umkondo minimum age is marked by intrusive dolerite in Zimbabwe dated at 1100 Ma while for the Ghairezi it is still not well established. The Gairezi Group was subjected to progressive metamorphism of Pan-African age. At the margin of the Zimbabwe Craton, in its northern part, metasedimentary units occur representing a passive margin of Neoproterozoic age. They make up the Rushinga Group, which includes felsic metavolcanic rocks dated at ca.800 Ma. Granulites and medium- to high-grade paragneisses, and migmatites of the Chimoio, Macossa and Mungari Groups of Neoproterozoic metamorphic age, overly the ortho-metamorphic pre-existing rock of ca. 1100 Ma, which belongs to the Báruè Magmatic Arc. They characterize the N-S trend Mozambique Belt, which appears to the east of the craton tectonically juxtaposed on the Archean rocks. The maximum age of deposition of these rocks, indicated by U-Pb dating of detrital zircons, is ca. 700 Ma and their minimum age is limited by a few monzonitic Cambrian intrusions dated at ca. 500 Ma. The Neoproterozoic bimodal Guro Suite, dated at ca. 850 Ma and composed of felsic and mafic members characterizes the east-dipping outer rim of the craton margin in the north. The felsic member comprises the Serra Banguatere aplitic granite gneiss-migmatite and the mafic member consists of the Magasso metagabbro and mafic gneiss-migmatite. The geochemical signature and bimodality are all characteristics of anorogenic, A-type granites. The tectono-thermal effects of the Pan-African orogenic event, of approximately 500 Ma, are visible along the margin of the Zimbabwe Craton. Deformation and metamorphism are progressive from the craton towards the belt, from greenschist facies to granulite facies. The main suture in the study area shall be placed along the frontal thrusts of the Mungari and Macossa/Chimoio nappes of Neoproterozoic to Cambrian age. To the west of the suture the rejuvenated margin of the craton occurs, indicated by K-Ar dating. To the east, the Mozambique Belt occurs with its paragneisses of the Neoproterozoic overlaying the Mesoproterozoic granitoids of the Báruè magmatic arc.
DS201909-2099
2019
Jamal, D.L.Turunen, S.T., Luttinen, A.V., Heinonen, J.S., Jamal, D.L.Luenha picrites, central Mozambique - messengers from a mantle plume source of Karoo continental flood basalts?Lithos, Vol. 346-347, 16p. PdfAfrica, Mozambiquepicrites

Abstract: We present geochemical and isotopic (Nd, Sr) data for a picrite lava suite from the Luenha River and adjacent areas in Mozambique. The Luenha picrites represent a previously unknown type of picrites related to the Karoo large igneous province (LIP) and are distinguished by their notably low TiO2 contents (0.3-1.0?wt%) and coupling of high Nb/Y with low Zr/Y and Sm/Yb. Relatively high CaO and low Zn/Fe point to a peridotitic mantle source. Contamination-sensitive incompatible element ratios show that one lava flow is likely to be uncontaminated by the crust and its composition suggests a mantle source with primitive mantle-like incompatible element ratios and mildly depleted isotopic ratios (initial 87Sr/86Sr?=?0.7041 and ?Nd?=?+1.4 at 180?Ma). The primary melts of the Luenha picrites had MgO contents in the range of 13-21?wt%. Our preferred estimate for a primary melt composition (MgO?=?18?wt%) resembles experimental melts of fertile mantle peridotite at 3-4?GPa and indicates liquidus temperature of 1445-1582?°C. Geochemical similarities suggest the Luenha picrites were generated from the same overall primitive mantle-like reservoir that produced the main volume of Karoo flood basalts in the Karoo, Kalahari, and Zambezi basins, whereas the previously identified enriched and depleted (upper) mantle sources of Karoo picrite suites (Mwenezi, Antarctica) were subordinate sources for flood basalts. We propose that the Luenha picrites record melting of a hot, chemically primitive mantle plume source that may have been rooted in the sub-African large low shear velocity province boundary and that such a source might have been the most significant magma source in the Karoo LIP.
DS200912-0333
2009
Jamasmie, C.Jamasmie, C.Nunavut: the epicentre of a new diamond exploration boom in Canada. Peregrine features. Stornoway mentioned.Mining Magazine, July pp. 16-17.Canada, NunavutNews item - Peregrine
DS200812-0637
2008
Jambion, A.Le Guillou, C., Rouzaud, J.N., Bourot-Denise, M., Remusat, L., Jambion, A.Laboratory shock synthesized diamond vs carbons from a differentiated meteorite.Goldschmidt Conference 2008, Abstract p.A532.Urelilite
DS1998-0512
1998
JambonGillet, Ph., Matas, Fiquet, Chamorro, Maryinez, JambonVolatiles in the Earth's mantle: insights from mineral and melt physicsMineralogical Magazine, Goldschmidt abstract, Vol. 62A, p. 521-2.MantleMagnesite, noble gases, volcanism.
DS1987-0441
1987
Jambon, A.Marty, B., Jambon, A.C/3He in volatile fluxes from the solid earth: implications for carbongeodynamicsEarth and Planetary Science Letters, Vol. 83, No. 1-4, May pp. 16-26GlobalGeochemistry
DS1992-0358
1992
Jambon, A.Deruelle, B., Dreibus, G., Jambon, A.Iodine abundances in oceanic basalts: implications for earth dynamicsEarth and Planetary Science Letters, Vol. 108, No. 4, February pp. 217-228GlobalGeochemistry, Oceanic basalts
DS1994-0287
1994
Jambon, A.Chaussidon, M., Jambon, A.Boron content and isotopic composition of oceanic basalts: geochemical and cosmochemical implicationsEarth and Planetary Science Letters, Vol. 121, pp. 277-291MantleOceanic basalts, Geochronology -boron
DS1998-0680
1998
Jambon, A.Jambon, A., Gillet, P., Chamorro, ColticeHelium and argon poor magmas from the under gassed mantleMineralogical Magazine, Goldschmidt abstract, Vol. 62A, p. 705-6.Hawaii, Mantlehelium, Geodynamics
DS2002-0105
2002
Jambon, A.Barrat, J.A., Jambon, A., Bohn, M., Gillet, P., Sautter, V., Gopei, C., Lesourd, M.Petrology and chemistry of the picritic shergottite north west AfricaGeochimica et Cosmochimica Acta, Vol.66, 19, pp.3505-18.West AfricaPicrites
DS201012-0323
2010
Jambon, Agrinier.DavailleJavoy, M., Kaminski, E., Guyot,Andrault, Sanloup, Moreira, Labrosse, Jambon, Agrinier.Davaille, JaupartThe chemical composition of the Earth: enstatite chondrite models.Earth and Planetary Science Letters, Vol. 293, 3-4, pp. 259-268.MantleChemistry
DS1990-0753
1990
Jambor, J.L.Jambor, J.L., Vaughan, D.J.Advanced microcopic studies of ore mineralsMineralogical Association of Canada Short Course Handbook, Vol. 17, 440pBookMicroscopy -ore minerals
DS1990-0754
1990
Jambor, J.L.Jambor, J.L., Vaughan, D.J.Advanced mircorscopic studies of ore mineralsMineralogical Association of Canada Short Course Handbook, Vol. 17, 440pGlobalBook -table of contents, Microscopy -ore minerals
DS1992-1411
1992
Jambor, J.L.Sinclair, W.D., Jambor, J.L., Birkett, T.C.Rare earths and the potential for rare earth deposits in CanadaThe Canadian Institute of Mining, Metallurgy and Petroleum (CIM) Exploration and Mining Geology, Vol. 1, No. 3, July pp. 265-282CanadaEconomics, overview, Rare earths
DS1993-1472
1993
Jambor, J.L.Sinclair, W.D., Jambor, J.L., Birkett, T.C.Rare earth deposits in Canada: alkaline complexes as potential sources of rare earth elements.Rare earth Minerals: chemistry, origin and ore deposits, International Geological Correlation Programme (IGCP) Project, pp. 128-130. abstractCanadaAlkaline rocks, rare earth elements (REE).
DS1994-0172
1994
Jambor, J.L.Blowes, D.W., Jambor, J.L.The environmental geochemistry of sulfide mine wastesMineralogical Association of Canada Short Course, Vol. 22, 110p. $ 30.00GlobalEnvironmental geochemistry, Table of contents, Mine wastes
DS2003-0063
2003
Jambor, J.L.Baker, M.J., Blowes, D.W., Logsdon, M.J., Jambor, J.L.Environmental geochemistry of kimberlite materials: Diavik diamonds project, Lac deExploration Mining Geology ( C.I.M.), Vol. 10, 3, pp. 155-63.Northwest TerritoriesGeochemistry - whole rock analyses, ABA results, Deposit - Diavik
DS200412-0086
2003
Jambor, J.L.Baker, M.J., Blowes, D.W., Logsdon, M.J., Jambor, J.L.Environmental geochemistry of kimberlite materials: Diavik diamonds project, Lac de Gras, Northwest Territories, Canada.Exploration Mining Geology , Vol. 10, 3, pp. 155-63.Canada, Northwest TerritoriesGeochemistry - whole rock analyses, ABA results Deposit - Diavik
DS201312-0849
2013
Jambor, J.L.Smith, L.J.D., Blowes, D.W., Jambor, J.L., Smith, L., Sego, D.C., Neuner, M.The Diavik waste rock project: initial geochemical response from a low sulfide waste rock pile.Applied Geochemistry, Vol. 36, pp. 200-209.Canada, Northwest TerritoriesMining - Diavik
DS2001-0325
2001
JamesFouch, M.J., James, Silver, VanDecar, Van der LeeImaging broad ranges in structural variations beneath the Kaapvaal and Zimbabwe Cratons, southern Africa.Slave-Kaapvaal Workshop, Sept. Ottawa, 5p. abstractSouth Africa, ZimbabweGeophysics - seismics, Tomography - Kimberley array
DS2001-0644
2001
JamesKwadiba, M., Wright, James, Kgaswane, Simon, Niu, SchuttCrustal phases and the structure of the crust beneath the Kaapvaal CratonSlave-Kaapvaal Workshop, Sept. Ottawa, 2p. abstractSouth AfricaTectonics, Geophysics - teleseismic
DS2001-0832
2001
JamesNguuri, T.K., Gore, James, Webb, Wright, Zengeni et al.Crustal structure beneath southern Africa and its implications for the formation and evolution of ...Geophysical Research Letters, Vol. 28, No. 13, July 1, pp. 2501-4.South AfricaTectonics, Craton - Kaapvaal and Zimbabwe
DS2001-1069
2001
JamesShirey, S.B., Harris, James, Deines, Richardson, et al.Geochemical and geophysical perspectives on diamond formation beneath southern Africa.Slave-Kaapvaal Workshop, Sept. Ottawa, 3p. abstractSouth AfricaGeochemistry - diamond inclusions, Diamond - genesis
DS2001-1182
2001
JamesVan der Lee, S., Van De Car, Fouch, JamesCombined sensitivity to the Kaapvaal tectosphere of regional and teleseismic surface and S Waves.Slave-Kaapvaal Workshop, Sept. Ottawa, 3p. abstractSouth AfricaGeophysics - seismics, Lithosphere
DS200712-0769
2006
JamesNadeau, L., Ryan, J.J., Hinchey, A.M., James, Sandeman, Tremblay, Schetselaar, Berman, DavisOutlook on the geology of the Boothia MaIn land area, Kitikmeot region, Nunavut.34th Yellowknife Geoscience Forum, p. 39-40. abstractCanada, NunavutGeology - brief overview
DS1996-0676
1996
James, C.James, C.Structuring Win/Win joint ventures ( eg. with Echo Bay)Southeast Asian Mining Conference, Sept. Toronto, 8p (slide diagrams not text)GlobalEconomics, Joint Ventures -alliances
DS1988-0218
1988
James, D.Fitton, J.G., James, D., Kempton, P.D., Ormerod, D.S., Leeman, W.P.The role of lithospheric mantle in the generation of late Cenozoic basic magmas in the Western UnitedStatesJournal of Petrology, Special Volume 1988- Oceanic and Continental, pp. 331-349United States, Colorado PlateauHopi Buttes
DS1995-0398
1995
James, D.Dawson, J.B., James, D., Paslick, m C., Halliday, A.Thermal anomay in the upper mantle beneath a propagating continental rift:evdience Labait VolcanoProceedings of the Sixth International Kimberlite Conference Extended Abstracts, p. 124-5.TanzaniaTectonics, magmatism, Carbonatite
DS1995-0870
1995
James, D.James, D., Christie, B.The Canadian diamond sector.. a sparkling new industry groupCanaccord, Oct. 19, 12p.Northwest Territories, Brazil, SaskatchewanNews item -research report, Aber, Canabrava, Dia Met, Kensington, Mountain Province
DS1995-1444
1995
James, D.Paslick, C., Halliday, A., James, D., Dawson, J.B.Enrichment of the continental lithosphere by Ocean Island Basalt (OIB) melts: isotopic evidence from volcanic province, Tanzania.Earth and Planetary Science Letters, Vol. 130, No. 1-4, Feb. pp. 109-126.TanzaniaGeochronology, Volcanics
DS2000-0440
2000
James, D.James, D., Fouch, M., Vandecar, J.Seismic studies of lithsopheric structure beneath southern Africa: implications for formation cratons...Geological Society of America (GSA) Abstracts, Vol. 32, No. 7, p.A-163.South AfricaCraton - evolution Kaapvaal, Geophysics - seismics
DS2001-0526
2001
James, D.James, D., Boyd, Bell, Schutt, CarlsonXenolith constraints on seismic velocities in the upper mantle beneath southern Africa.Slave-Kaapvaal Workshop, Sept. Ottawa, 2p. abstractSouth Africa, BotswanaGeophysics - seismics, Tomography - Kaapvaal Craton
DS2001-0527
2001
James, D.James, D., Rokosky, Nguuri, Gore, Niu, WebbCrustal formation in the Archean: constraints from the southern Africa seismic experiment.Slave-Kaapvaal Workshop, Sept. Ottawa, 2p. abstractSouth Africa, BotswanaGeophysics - seismics, Brief review of crustal structure studies
DS2001-1199
2001
James, D.Ven der Lee, S., James, D., Silver, P.Upper mantle S velocity structure of central and south AmericaJournal of Geophysical Research, Vol. 106, No. 12, pp. 30,821-34.South AmericaTectonics, Geophysics
DS2001-1226
2001
James, D.Wen. L., Silver, P., James, D., Kuehnel, R.Seismic evidence for a thermo chemical boundary at the base of the Earth'smantle.Earth and Planetary Science Letters, Vol. 189, No. 3-4, July 15, pp. 141-54.MantleGeophysics - seismics, Boundary
DS200412-0477
2004
James, D.Downes, H., Macdonald, R., Upton, B.G.J., Cox, K.G., Bodinier, J-L., Mason, P.R.D., James, D., Hill, P.G., HeaUltramafic xenoliths from the Bearpaw Mountains, Montana: USA: evidence for multiple metasomatic events in the lithospheric mantJournal of Petrology, Vol. 45, 8, pp. 1631-1662.United States, MontanaMetasomatism
DS1994-0824
1994
James, D.E.James, D.E.P and S seismic velocities in the upper mantle transition zone beneath The western Brazilian shield.International Symposium Upper Mantle, Aug. 14-19, 1994, pp. 124-126.BrazilGeophysics -seismics, Mantle
DS1994-0825
1994
James, D.E.James, D.E.Structure and dynamics of the continental lithosphere: a reviewInternational Symposium Upper Mantle, Aug. 14-19, 1994, pp. 151-164.Canada, Superior ProvinceGeodynamics, Lithosphere, orogeny, Trans Hudson
DS1994-0826
1994
James, D.E.James, D.E., Snoke, J.A.Structure and tectonics in the region of flat subduction beneath centralPeru: crust and uppermost mantleJournal of Geophy. Research, Vol. 99, No. B4, April 10, pp. 6899-6912PeruTectonics, Structure
DS1994-1647
1994
James, D.E.Snoke, J.A., James, D.E.Structure of the continental lithosphere beneath southeast Brasil from surfacewave inversion: prel. results.International Symposium Upper Mantle, Aug. 14-19, 1994, pp. 121-123.BrazilTectonics, Lithosphere
DS1998-0681
1998
James, D.E.James, D.E., et al.Review of seismic structure of the continental lithosphere with results from the Southern Africa....7th International Kimberlite Conference Abstract, pp. 366-70.South AfricaGeophysics - seismics, Tomography, discontinuity, anistrophy structure
DS2001-0528
2001
James, D.E.James, D.E., Fouch, D.J., Van De Car, M.J., VanderleeTectosphere structure beneath southern AfricaGeophysical Research Letters, Vol. 28, No. 13, July 1, pp. 2485-88.South AfricaTectonics
DS2002-0761
2002
James, D.E.James, D.E., Fouch, M.J.Formation and evolution of Archean cratons: insights from southern AfricaGeological Society of London Special Publication, No. 199, pp. 1-26.South AfricaTectonics
DS2002-1144
2002
James, D.E.Niu, F., James, D.E.Fine structure of the lowermost crust beneath the Kaapvaal Craton and its implication for crustal formation and evolution.Earth and Planetary Science Letters, Vol. 200, 1-2, pp. 121-30.South AfricaTectonics
DS2002-1465
2002
James, D.E.Shirey, S.B., Harris, J.W., Richardson, S.H., Fuch, M.J., James, D.E., CartignyDiamond genesis, seismic structure and evolution of the Kaapvaal Zimbabwe CratonScience, No. 5587, Sept. 6, pp. 1683-5.South Africa, ZimbabweTectonics - diamond genesis, Geophysics - seismics
DS2003-0644
2003
James, D.E.James, D.E.Imaging crust and upper mantle beneath southern Africa: the southern Africa broadbandLeading Edge, Vol. 22, 3, pp. 238-49.South AfricaGeophysics - seismics
DS2003-0645
2003
James, D.E.James, D.E., Niu, F., Rokosky, J.Crustal structure of the Kaapvaal craton and its significance for early crustal evolutionLithos, Vol. 71, 2-4, pp. 413-429.South AfricaGeophysics - seismics, tectonics
DS2003-1267
2003
James, D.E.Shirey, S.B., Harris, J.W., Richardson, S.H.,Fouch, M., James, D.E., CartignyRegional patterns in the paragenesis and age of inclusions in diamond, diamondLithos, Vol. 71, 2-4, pp. 243-258.South AfricaDiamond inclusions
DS200412-0567
2004
James, D.E.Fouch, M.J., James, D.E., Van De Car, J.C., Van Der Lee, S.Mantle seismic structure beneath the Kaapvaal and Zimbabwe Cratons.South African Journal of Geology, Vol. 107, 1/2, pp. 33-44.Africa, South Africa, ZimbabweGeophysics - seismics, tectonics, magmatism
DS200412-0901
2003
James, D.E.James, D.E.Imaging crust and upper mantle beneath southern Africa: the southern Africa broadband seismic experiment.Leading Edge, Vol. 22, 3, pp. 238-49.Africa, South AfricaGeophysics - seismics
DS200412-0902
2003
James, D.E.James, D.E., Niu, F., Rokosky, J.Crustal structure of the Kaapvaal craton and its significance for early crustal evolution.Lithos, Vol. 71, 2-4, pp. 413-429.Africa, South AfricaGeophysics - seismics, tectonics
DS200412-1439
2004
James, D.E.Niu, F., Levander, A., Cooper, C.M., Lee, C.T., Lenardic, A., James, D.E.Seismic constraints on the depth and composition of the mantle keel beneath the Kaapvaal craton.Earth and Planetary Science Letters, Vol. 224, 3-4, pp. 337-346.Africa, South AfricaGeophysics - seismics, boundary
DS200412-1806
2003
James, D.E.Shirey, S.B., Harris, J.W., Richardson, S.H.,Fouch, M., James, D.E., Cartigny, P.,Deines, P., Vijoen, F.Regional patterns in the paragenesis and age of inclusions in diamond, diamond composition and the lithospheric seismic structurLithos, Vol. 71, 2-4, pp. 243-258.Africa, South AfricaDiamond inclusions
DS200512-0140
2005
James, D.E.Carlson, R.W., Pearson, D.G., James, D.E.Physical, chemical and chronological characteristics of continental mantle.Reviews of Geophysics, Vol. 43, 1, RG1001 10.1029/2004 TG000156MantleGeochemistry
DS200612-0766
2006
James, D.E.Larson, A.M., Snoke, J.A., James, D.E.S-wave velocity structure, mantle xenoliths and the upper mantle beneath the Kaapvaal Craton.Geophysical Journal International, Vol. 167, 1, Oct., pp. 171-186.Africa, South AfricaGeophysics - seismics
DS201012-0245
2010
James, D.E.Gore, J., James, D.E., Zengeni, T.G., Gwavava, O.Crustal structure of the Zimbabwe craton and the Limpopo belt of southern Africa: new constraints from seismic dat a and implications for its evolution.South African Journal of Geology, Vol. 112, pp. 213-228.Africa, Zimbabwe, South Africa, BotswanaGeophysics - seismics
DS1989-0698
1989
James, D.R.James, D.R.Claude Resources Inc. (CRJ) -$ 4.50 Diamonds inSaskatchewan. Special situation reportRichardson Greenshields Equity Research, No. 89-102, August 10, 1989, 10pSaskatchewanCompany profile, Claude-Corona
DS1992-0769
1992
James, D.R.James, D.R.Diamonds in the North Lac de Gras, Northwest Territories diamond playRichardson Greenshields Equity Research, No. 92-79, May 28, 10pNorthwest TerritoriesNews item, BHP, Dia Met
DS1993-0735
1993
James, D.R.James, D.R.Diamond mining at Lac de Gras Northwest Territories... The race is onRichardson Greenshields Equity Research, No. 93-167, October 20, 19p.Northwest TerritoriesResearch Report, Dia Met, BHP
DS1996-0677
1996
James, D.R.James, D.R.The Canadian diamond sector.. an update on selected exploration/developmentprojects.Canaccord, May 30, pp. 1-8.Northwest Territories, Ontario, SaskatchewanBrief overview, Diamond exploration
DS1995-0345
1995
James, D.T.Connelly, J.N., Rivers, T., James, D.T.Thermotectonic evolution of the Grenville Province of western LabradorTectonics, Vol. 14, No. 1, February pp. 202-217Labrador, QuebecTectonics, Terranes
DS1995-0346
1995
James, D.T.Connelly, J.N., Rivers, T., James, D.T.Thermotectonic evolution of the Grenville Province of western LabradorTectonics, Vol; . 14, No. 1, Feb. pp. 202-217.Labrador, Ungava, QuebecTectonics
DS1996-0678
1996
James, D.T.James, D.T., Connelly, J.N., Wasteneys, H.A., Kilfoil, G.J.Paleoproterozoic lithotectonic divisions of the southeastern ChurchillProvince, western LabradorCanadian Journal of Earth Sciences, Vol. 33, No. 2, Feb. pp. 216-230Labrador, Quebec, UngavaTectonics, Geochronology, Nain Craton, Superior Craton
DS2000-0441
2000
James, D.T.James, D.T., Duning, G.R.uranium-lead (U-Pb) geochronological constraints for Paleoproterozoic evolution of the Core Zone, southeastern Churchill ProvPrecambrian Research, Vol. 103, No. 1-2, Sept. pp. 31-54.Saskatchewan, Manitoba, Western CanadaGeochronology, Churchill Province
DS2000-0442
2000
James, D.T.James, D.T., Dunning, G.R., Fairchild, T.R.Proterozoic microfossils from subsurface siliclastic rocks of the Sao Francico Craton, south central Brasil.Precambrian Research, Vol. 103, No. 1-2, Sept.pp. 31-54.Brazil, south centralCraton - Sao Francisco
DS2001-0529
2001
James, D.T.James, D.T.Paleoproterozoic (>1.75) crustal growth and architecture in the region between Superior ....Geological Association of Canada (GAC) Annual Meeting Abstracts, Vol. 26, p.71, abstract.Quebec, LabradorTectonics - New Quebec orogen, North Atlantic Craton - a review
DS2001-0530
2001
James, D.T.James, D.T., Ryan, A.B.The Saglek and Hopedale blocks of the Western North Atlantic Craton: a review of 1.4 Billion years evol.Geological Association of Canada (GAC) Annual Meeting Abstracts, Vol. 26, p.71, abstract.Quebec, LabradorTectonics, Geochronology
DS2002-0762
2002
James, D.T.James, D.T., Kamo, S., Krogh, T.Evolution of 3.1 and 3.0 Ga volcanic belts and a new thermotectonic model for the Hopedale Block, North Atlantic Craton, Canada.Canadian Journal of Earth Science, Vol.39,5, May, pp.687-710.Quebec, Labrador, GreenlandTectonics - regional framework
DS2002-1688
2002
James, D.T.Wardle, R.J., James, D.T., Scott, D.J., Hall, J.The southeastern Churchill Province: synthesis of a Paleoproterozoic transpressional orogen.Canadian Journal of Earth Science, Vol.39,5, May, pp.639-63.Quebec, Labrador, Baffin IslandGeophysics - Torngat, New Quebec orogens, Trans Hudson, Tectonics - Nain, Superior Craton
DS200812-0973
2007
James, D.T.Ross, M., Utting, D.J., Hodgson, D.A., James, D.T.Ice flow and dispersal patterns on Southampton Island Nunavut: a preliminary Assessment. ( KIMs)35th. Yellowknife Geoscience Forum, Abstracts only p. 52.Canada, NunavutGeochemistry - samples
DS200812-0998
2008
James, D.T.Sanborn-Barrie, M., Chakungal, J., James, D.T., Whalen, J., Rayner, N., Berman, R.G., Craven, J., Coyle, M.New understanding of the geology and diamond prospectivity of Southampton Island, central Nunavut.Northwest Territories Geoscience Office, p. 53-54. abstractCanada, NunavutDeposit - Qilalugaq
DS201012-0797
2009
James, D.T.Tremblay, T., Ryan, J.J., James, D.T., Kjarsgaard, I.M.Kimberlite indicator mineral survey and ice flow studies in Boothia maIn land 57A,B,C,D. Kitikmeot region, Nunavut.Geological Survey of Canada, Open file 6040 31p. CD $ 9.10Canada, NunavutGeochemistry
DS1993-0736
1993
James, E.W.James, E.W., Henry, C.D.Southeastern extent of the North American craton in Texas and northern Chihuahua as revealed by lead isotopesGeological Society of America (GSA) Bulletin, Vol. 105, No. 1, January pp. 116-126Texas, MexicoCraton, tectonics
DS1992-0770
1992
James, H.L.James, H.L.Precambrian iron formations: nature, origin and mineralogic evolution from sedimentation to metamorphismin: Diagenesis III, editors Wolf, K.H., Chilingarian, G.V, Vol. 11, pp. 543-589GlobalIron Formations -Precambrian, Nature, origin and mineralogy
DS1960-0560
1965
James, L.D.James, L.D.Regional Geochemical Reconnaissance in the Northern and Southern Sections of the Sula Mountains Schist Belt.London: Ph. D. Thesis, University London., 401P.Sierra Leone, West Africa, Kangari HillsGeochemistry, Regional Studies, Chromite
DS1960-0719
1966
James, L.D.Nicol, I., James, L.D., Viewing, K.D.Regional Geochemical Reconnaissance in Sierra LeoneInstitute of Mining and Metallurgy. Transactions, Vol. 75, PP. B146-161.Sierra Leone, West AfricaGeochemistry, Kimberlite, Diamonds
DS1991-1325
1991
James, N.P.Pelechaty, S.M., James, N.P., Kerans, C., Grotzinger, J.P.A middle Proterozoic paleokarst unconformity and associated sedimentaryrocks, Elu basin, Northwest CanadaSedimentology, Vol. 38, No. 5, October pp. 775-798Northwest TerritoriesBasin, Proterozoic
DS2003-0862
2003
James, P.Mahoney, S., James, P., Mauger, A., Heinson, G.Geologic and regolith mapping for mineral exploration in the Gawler Craton of SouthInternational Geoscience and Remote Sensing Symposium, Vol. 3, pp. III 1779-81. Ingenta 1034976078AustraliaRemote sensing
DS200412-1202
2003
James, P.Mahoney, S., James, P., Mauger, A., Heinson, G.Geologic and regolith mapping for mineral exploration in the Gawler Craton of South Australia using Hyperion and other remote seInternational Geoscience and Remote Sensing Symposium, Vol. 3, pp. III 1779-81. Ingenta 1034976078AustraliaRemote sensing
DS200512-0115
2004
James, R.H.Brooker, R.A., James, R.H., Blundy, J.D.Trace elements and Li isotope systematics in Zabargad peridotites: evidence of ancient subduction processes in the Red Sea mantle.Chemical Geology, Vol. 212, 1-2, pp. 179-204.Mantle, EuropeSubduction
DS200712-0407
2007
James, R.H.Hammond, S.J., Parkinson, I.J., James, R.H., Rogers, N.W., Harvey, J.Delta 7 Li systematics of mantle xenoliths from Kilbourne Hole: unravelling metasomatic and differential processes.Plates, Plumes, and Paradigms, 1p. abstract p. A373.United States, New Mexico, Colorado PlateauMetasomatism
DS1991-1320
1991
James, R.S.Peck, D.C., James, R.S.Geology and platinum group element sulphide mineralization, East BulletinLakeOntario Geological Survey Open File, Report No. 5813, 65pOntarioPlatinuM., Deposit -East Bulletin Lake
DS1995-0318
1995
James, R.S.Chubb, P.T., Peck, D.C., James, R.S., Ercit, T.S.Nature and origin of nodular textures in anorthositic cumulates from the east Bulletin intrusion, OntarioMineralogy and Petrology, Vol. 54, No. 1-2, pp. 93-104OntarioAnorthosites, layered intrusion, Deposit -East Bulletin
DS1998-1549
1998
James, R.S.Vogel, D.C., Vuollo, J.I., James, R.S.Tectonic, stratigraphic and geochemical comparisons between ca 2500-2440 Mamafic igneous events - shield.Precambrian Research, Vol. 92, No. 2, Oct.l, pp. 89-116Canada, FennoscandiaTectonics - shield, Geochemistry
DS1998-1550
1998
James, R.S.Vogel, D.C., Vuollo, J.I., James, R.S.Tectonic, stratigraphic and geochemical comparisons between 2500-2440 Mamafic igneous events ...shieldPrecambrian Research, Vol. 92, No. 2, Oct. 1, pp. 89-116.Canada, FennoScandia, Finland, DenmarkTectonics - shield, Geochemistry
DS1992-0888
1992
James, S.D.Kostopoulos, D.K., James, S.D.Parameterization of melting regime of shallow upper mantle and effects of variable lithospheric stretching on mantle modal stratification, trace elementmagmasJournal of Petrology, Vol. 33, No. 3, pp. 665-691MantleModel, Upper mantle -magmas
DS1994-1806
1994
James, T.Turner, B.L., James, T.Developing a diamond mine: sequence versus synchronismThe Canadian Institute of Mining, Metallurgy and Petroleum (CIM) District 6, Oct. 11-15th. Vancouver, p.66 abstract onlyNorthwest TerritoriesEnvironment, Land management
DS1950-0395
1958
James, T.C.James, T.C., Mckie, D.The Alteration of Pyrochlore to Columbite in Carbonatites In Tanganyika.Mineralogical Magazine., Vol. 31, No. 242, SEPT. PP. 889-907.Tanzania, East AfricaMineralogy
DS1992-0771
1992
James, T.S.James, T.S.The Hudson Bay free-air gravity anomaly and glacial reboundGeophysical Research Letters, Vol. 19, No. 9, May 4, pp. 861-864OntarioGeophysics-gravity, Geomorphology
DS1991-1149
1991
James, W.C.Mickus, K.L., James, W.C.Regional gravity studies in southeastern California, western Arizona, and southern NevadaJournal of Geophysical Research, Vol. 96, No. B7, July 10, pp. 12, 333-12, 351Arizona, NevadaStructure, Geophysics -gravity
DS1992-0974
1992
James, W.C.Mack, G.H., James, W.C.Paleosols for sedimentologistsGeological Society of America Short Course, Notes, 125pGlobalShort Course, Sedimentology, paleosols
DS1993-0949
1993
James, W.C.Mack, G.H., James, W.C., Monger, H.C.Classification of paleosolsGeological Society of America (GSA) Bulletin, Vol. 105, No. 2, February pp. 129-136GlobalLaterites, Paleosols
DS1994-1080
1994
James, W.C.Mack, G.H., James, W.C.Paleoclimate and the global distribution of paleosolsJournal of Geology, Vol. 102, No. 3, May pp. 360-366GlobalPaleoclimate, Paleosols, Laterites
DS1994-1081
1994
James, W.C.Mack, G.H., James, W.C.Paleoclimate and the global distribution of paleosolsJournal of Geology, Vol. 102, No. 3, May pp. 360-366.GlobalPaleosols -not specific to diamonds
DS1982-0296
1982
James Capel And CoJames Capel And CoThe World Diamond IndustryLondon: James Capel And Co., NOT KNOWN.GlobalKimberley, Mineral Economics, Markets, Cso, Industry Review
DS1998-1594
1998
JamiesonWu, W.J., Lines, L., Burton, Lu, Zhu, Jamieson, BordingPrestack depth migration of an Alberta foothills dat a set: the Husky experience.Geophysics, Vol. 63, No. 2, pp. 392-8.AlbertaGeophysics - seismics, Tectonics, thrust
DS201312-0435
2013
Jamieson, A.Jamieson, A., Beaumont, C.On the origin of orogens.Geological Society of America Bulletin, Vol. 125, pp. 1671-1702.TechnologyOrogen
DS1990-0755
1990
Jamieson, B.Jamieson, B.De Beers coup spurs the rush to RussiaSunday Telegraph, July 29, 1/4pRussiaNews item, De Beers and Russia
DS1990-0756
1990
Jamieson, B.Jamieson, B.Red alert as the Soviet Union's diamonds come in from the coldSunday Telegraph, July 29, 1pRussiaNews item, De Beers and Russia
DS1960-0531
1965
Jamieson, B.G.Cox, K.G., Jamieson, B.G.Progress Report on Karroo Volcanic StudiesLeeds University Research Institute of African Geology Annual Report, Vol. 3B, PP. 37-39.South Africa, BotswanaGeology
DS2001-1000
2001
Jamieson, D.N.Ryan, C.G., Jamieson, D.N., Griffin, W.L., CrippsThe new CSIRO GEMOC nuclear microprobe: first results, performance and recent applications.Nuclear Institute Methods Phys. Res., Vol. B 181, pp. 12-19.GlobalProton microprobe
DS2003-1179
2003
Jamieson, H.E.Rolla, A., Jamieson, H.E.Processed kimberlite water interactions in diamond mine waste, Ekati diamond mineGeological Association of Canada Annual Meeting, Abstract onlyNorthwest TerritoriesMining - waste
DS2003-1180
2003
Jamieson, H.E.Rollo, H.A., Jamieson, H.E.Processes kimberlite - water interactions in diamond mine waste, Ekati diamond mine8ikc, Www.venuewest.com/8ikc/program.htm, Session 1 POSTER abstractNorthwest TerritoriesKimberlite geology and economics, Mining - tailings, environment
DS200412-1685
2003
Jamieson, H.E.Rolla, A., Jamieson, H.E.Processed kimberlite water interactions in diamond mine waste, Ekati diamond mine, N.W.T. Canada.Geological Association of Canada Annual Meeting, Abstract onlyCanada, Northwest TerritoriesMining - waste
DS200612-1172
2006
Jamieson, H.E.Rollo, H.A., Jamieson, H.E.Interaction of diamond mine waste and surface water in the Canadian Arctic.Applied Geochemistry, Vol. 21, 9, pp. 1522-1538.Canada, Northwest TerritoriesMining
DS200712-0609
2007
Jamieson, H.E.Lee, C.A., Rollo, H.A., Jamieson, H.E.Rock water interaction and CO2 sequestration associated with kimberlite ore processing.Geological Association of Canada, Gac-Mac Yellowknife 2007, May 23-25, Volume 32, 1 pg. abstract p.47.TechnologyMineral processing
DS201212-0315
2012
Jamieson, H.E.Hudson-Edwards, K.A., Jamieson, H.E., Lottermoser, B.G.Mine wastes: past present, future * not specific to diamond mines - good general knowledgeElements, Vol. 7, 6, Dec. pp. 375-380.GlobalDescription of mine wastes - history
DS201012-0045
2010
Jamieson, R.Beaumont, C., Jamieson, R., Nguyen, M.Models of large, hot orogens containing a collage of reworked and accreted terranes.Canadian Journal of Earth Sciences, Vol. 47, 4, pp. 485-515.MantleCraton
DS1991-0327
1991
Jamieson, R.A.Culshaw, N., Corrigan, D., Jamieson, R.A., Ketchum, J., Wallace, P.Traverse of the Central Gneiss Belt, Grenville Province, Georgian Bay, OntarioGeological Association of Canada (GAC) Annual Meeting held Toronto May 1991, Guidebook, No. B3, 35pOntarioCentral Gneiss Belt, Structure
DS1997-0233
1997
Jamieson, R.A.Culshaw, N.G., Jamieson, R.A., Ketchum, J.W.F., et al.Transect across the northwestern Grenville orogen, Georgian Bay Ontario:polystage convergence.. extensionTectonics, Vol. 16, No. 6, Dec. pp. 966-982.OntarioTectonics, Lower Orogenic Crust
DS2000-0443
2000
Jamieson, R.A.Jamieson, R.A., Beaumont, Vanderhaeghe, FullsackHow does the lower crust get hot?Geological Association of Canada (GAC)/Mineralogical Association of Canada (MAC) 2000 Conference, 2p. abstract.MantleMagma - heat production
DS2002-0763
2002
Jamieson, R.A.Jamieson, R.A., Beaumont, C., Nguyen, M.H., Lee, B.Interaction of metamorphism, deformation and exhumation in large convergent orogensJournal of Metamorphic Geology, Vol.20,1,pp. 9-24.GlobalOrogens - tectonics - not specific to diamonds
DS2003-1409
2003
Jamieson, R.A.Van der Hagaeghe, O., Medvedev, S., Fullsack, P., Beaumont, C., Jamieson, R.A.Evolution of orogenic wedges and continental plateaux: insights from crustalGeophysical Journal International, Vol. 153, 1, pp. 27-51.MantleGeothermometry, Subduction
DS200412-2035
2003
Jamieson, R.A.Van der Hagaeghe, O., Medvedev, S., Fullsack, P., Beaumont, C., Jamieson, R.A.Evolution of orogenic wedges and continental plateaux: insights from crustal thermalmechanical models overlying subducting mantlGeophysical Journal International, Vol. 153,1, pp. 27-51.MantleGeothermometry Subduction
DS200612-0297
2006
Jamieson, R.A.Culshaw, N.G., Beaumont, C., Jamieson, R.A.The orogenic superstructure infrastructure concept: revisited, quantified, and revived.Geology, Vol. 34, 9, Sept. pp. 733-736.Canada, Ontario, Manitoba, Superior ProvinceTectonics, geophysics - seismics
DS200812-1242
2008
Jamieson, R.A.Warren, C.J., Beaumont, C., Jamieson, R.A.Modelling tectonic styles and ultra high pressure UHP rock exhumation during the transition from oceanic subduction to continental collision.Earth and Planetary Science Letters, Vol. 267, 1-2, pp.129-145.MantleSubduction
DS200812-1243
2008
Jamieson, R.A.Warren, C.J., Beaumont, C., Jamieson, R.A.Deep subduction and rapid exhumation: role of crustal strength and strain weakening in continental crust and ultrahigh pressure rock exhumation.Tectonics, Vol. 27, TC6002.MantleSubduction
DS200912-0040
2009
Jamieson, R.A.Beaumont, C., Jamieson, R.A., Butler, J.P., Warren, C.J.Crustal structure: a key constraint on the mechanism of ultra high pressure rock exhumation.Earth and Planetary Science Letters, Vol. 287, 1-2, pp. 116-129.MantleUHP
DS201112-0475
2011
Jamieson, R.A.Jamieson, R.A., Unsworth, M.J., Harris, N.B.W., Rosenberg, C.L., Schulmann, K.Crustal melting and the flow of mountains.Elements, Vol. 7, 4, August pp. 253-260.Mantle, AsiaCrustal deformation - weakening
DS201212-0099
2012
Jamieson, R.A.Butler, J.P., Jamieson, R.A., Steenkamp, H.M., Robinson, P.Discovery of coesite eclogite from the Nordyane UHP domain, Western Gneiss region, Norway: field relations, metamorphic history and tectonic significance.Journal of Metamorphic Geology, in press availableEurope, NorwayCoesite
DS201412-0423
2013
Jamieson, R.A.Jamieson, R.A., Beaumont, C.On the origin of orogens.Geological Society of America Bulletin, Vol. 125, pp. 1671-1702.TechnologyOrogen
DS201805-0941
2018
Jammes, S.Chenin, P., Picazo, S., Jammes, S., Manatschal, G., Muntener, O., Karner, G.Potential role of lithospheric mantle composition in the Wilson cycle: a North American perspective.Geological Society of London, Special Publication, Vol. 470, doi:10.1144 /SP470.10Mantlewilson cycle

Abstract: Although the Wilson cycle is usually considered in terms of wide oceans floored with normal oceanic crust, numerous orogens result from the closure of embryonic oceans. We discuss how orogenic and post-orogenic processes may be controlled by the size/maturity of the inverted basin. We focus on the role of lithospheric mantle in controlling deformation and the magmatic budget. We describe the physical properties (composition, density, rheology) of three types of mantle: inherited, fertilized and depleted oceanic mantle. By comparing these, we highlight that fertilized mantle underlying embryonic oceans is mechanically weaker, less dense and more fertile than other types of mantle. We suggest that orogens resulting from the closure of a narrow, immature extensional system are essentially controlled by mechanical processes without significant thermal and lithological modification. The underlying mantle is fertile and thus has a high potential for magma generation during subsequent tectonic events. Conversely, the thermal state and lithology of orogens resulting from the closure of a wide, mature ocean are largely modified by subduction-related arc magmatism. The underlying mantle wedge is depleted, which may inhibit magma generation during post-orogenic extension. These end-member considerations are supported by observations derived from the Western Europe-North Atlantic region.
DS1996-0121
1996
Jams, W.J.Berger, A.R., Jams, W.J.Geoindicators - assessing rapid environmental changes in earth systemsBalkema, 470pGlobalEnvironment, water systems, semi, arid, Table of contents
DS2000-0955
2000
JamtveitTorsvik, T.H., Tucker, R.D., Ashwal, Carter, JamtveitLate Cretaceous India Madagascar fit and timing of break up related magmatisnTerra Nova, Vol. 12, No. 5, Oct. pp. 220-4.India, Madagascar, GondwanaGeochronology, Gondwana, tectonics
DS1996-0679
1996
Jamtveit, B.Jamtveit, B., Yardley, B.Fluid flow and transport in rocks: mechanisms and effectsChapman and Hall, ITP Distributors, approx. 150.00GlobalBook -ad, Sedimentary basins, fluid flow
DS1998-1430
1998
Jamtveit, B.Svensen, H., Jamtveit, B., Yardley, B., Austrheim, H.Eclogite facies fluids from the Caledonides of western Norway: compositions and implications for fluid-rock...Mineralogical Magazine, Goldschmidt abstract, Vol. 62A, p. 1481-2.NorwayEclogites, Fluid geochemistry
DS2001-1143
2001
Jamtveit, B.Svensen, H., Jamtveit, B., Austrheim, H.Halogen contents of eclogite facies fluid inclusions and minerals: Caledonides, western Norway.Earth and Planetary Science Letters, Vol. 186, No. 1, Mar. 15, pp.165-78.NorwayEclogites, Metasomatism
DS200512-0941
2005
Jamtveit, B.Schmalholz, S.M., Podladchikov, Y.Y., Jamtveit, B.Structural softening of the lithosphere.Terra Nova, Vol. 17, 1, pp. 66-72.MantleTectonics
DS1991-0024
1991
Jamveit, B.Andersen, T.B., Jamveit, B., Dewey, J.F., Swensson, E.Subduction and education of continental crust: major mechanisms during continent-continent collision and orogenic extensional collapse, a model Based on NorwegTerra Nova, Vol. 3, No. 3, pp. 303-310NorwayTectonics, Caledonides
DS201012-0320
2010
Jamveit, B.Jamveit, B.Metamorphism: from patterns to processes.Elements, Vol. 6, 3, pp. 149-152.MantleRates, systems
DS2001-0847
2001
Jan. M.O'Brien, P.J., Zotov, N., Law, R., Khan, M.A., Jan. M.Coesite in Himalayan eclogite and implications for models of India Asia collision.Geology, Vol. 29, No. 5, May, pp. 435-8.GlobalEclogite, coesite, metamorphism
DS1997-0550
1997
Jana, D.Jana, D., Walker, D.The impact of carbon on element distribution during core formationGeochimica et Cosmochimica Acta, Vol. 61, No. 13, pp. 2759-2763.GlobalSilicate partition, Carbon
DS201910-2241
2019
Jana, D.Ackerman, L., Polak, L., Magna, T., Rapprich, V., Jana, D., Upadhyay, D.Highly siderophile element geochemistry and Re-Os isotopic systematics of carbonatites: insights from Tamil Nadu, India.Earth and Planetary Science letters, Vol. 520, pp. 175-187.Indiacarbonatites

Abstract: Carbonatite metasomatism has been widely implicated for worldwide mafic mantle suites but so far, no combined data have been available for highly siderophile element systematics (HSE - Os, Ir, Ru, Pt, Pd, Re) and Re-Os isotopic compositions in carbonatites themselves. We present the first systematic survey of the HSE and Re-Os isotopic compositions in a suite of well-characterized Neoproterozoic carbonatites, silicocarbonatites and associated silicate rocks (pyroxenites, monzogabbros, syenites) from south India in order to place constraints on the HSE systematics in carbonatite magmas, anchoring possible mantle sources of carbonatites and relationship to the ambient crustal lithologies as well as preliminary constraints on carbonatite metasomatism in Earth's mantle. The most plausible explanation for generally low HSE contents in calciocarbonatites from Tamil Nadu (?HSE < 1.22 ppb) involves a low-degree (<1%) partial melting of the mantle source producing sulfur-saturated carbonatitic magmas leaving behind sulfide phases retaining HSE. The new data also indicate a strong FeO control on the distribution of Os and Pt during segregation of carbonatite melt from its enriched mantle source and/or melt differentiation. The combined 187Re/188Os values (from 0.10 to 217), 187Os/188Os ratios (0.186-10.4) and initial ?Os values back-calculated to 800 Ma (from +0.1 to +6052) predict that most Tamil Nadu calciocarbonatites were plausibly derived from a carbonated peridotite source with <10% recycled component. This model would thus provide significant constraints on the origin/source of carbonatites, irrespective of their post-emplacement history. The unusual, volumetrically rare, Mg-Cr-rich silicocarbonatites (?HSE = 14-41 ppb) display almost identical HSE patterns with those of host pyroxenites and predominantly high Pt (up to 38 ppb), the origin of which remains unknown. Positive co-variations between Pt, Pd and Re, and the well-developed positive correlation between Pt and MgO in these Mg-Cr-rich silicocarbonatites argue for a source coming predominantly from the upper mantle. The Re-Os isotopic systematics agree with direct incorporation of enriched mantle-derived material into parental melts but variable incorporation of potassium-rich crustal materials is evidenced by highly positive ?Os800 Ma values for a sub-suite of Mg-Cr-rich silicocarbonatites, indicating intense fenitization. The highly radiogenic Os isotopic compositions of monzogabbros and a syenite argue for their derivation from crustal lithologies with no or only negligible contribution of mantle material. Collectively, low Ir, Ru, Pt and Pd contents found in the Tamil Nadu carbonatites appear to indicate the incapability to significantly modify the total budget of these elements in the Earth's mantle during carbonatite metasomatism. In contrast, very high Re/Os ratios found in some of the analyzed carbonatites, paralleled by extremely radiogenic 187Os/188Os signature, can produce large modification of the Re-Os isotopic composition of mantle peridotites during carbonatite melt percolation when high melt/rock ratios are achieved.
DS201810-2372
2018
Janaina, N.Rielli A., Tomkins, A.G., Nebel, O., Raveggi, M., Jeon, H., Martin, L., Laure, A., Janaina, N.Sulfur isotope and PGE systematics of metasomatised mantle wedge.Earth and Planetary Science Letters, Vol. 497, 1, pp. 181-192.Mantlemetasomatism

Abstract: At convergent margins fluids liberated from subducting slabs metasomatise the overlying mantle wedge, enriching it in volatiles, incompatible elements and possibly ore-forming metals. Despite the genetic link between this process, the genesis of arc magmas, and formation of porphyry Cu-Au deposits, there is currently little understanding of the behaviour of chalcophile and siderophile elements during subduction-related mantle metasomatism. In this study, we report sulfur isotopic compositions and PGE concentrations of sulfides in a suite of garnet peridotites from the Western Gneiss Region of Norway, sampling mantle wedge from ?100 to ?250 km depth. Sulfides hosted in metasomatised samples have deviated from typical mantle values, ranging between ?10.0 and +5.4‰, indicating derivation of sulfur from subducted crust. Sulfides in pervasively metasomatised samples have atypical PGE signatures, with strong enrichment in Os and Ru relative to Ir, whereas channelised fluid flow produced sulfides extremely enriched in Pd, up to 700 times the concentration found in non-metasomatised samples. These signatures are reconcilable with a high oxidation state of the metasomatising agents and demonstrate that subduction can recycle chalcophile and siderophile elements into and within the mantle, along with sulfur. We further show that because the solubility of Os and Ru in fluids is redox sensitive, and Pd is more soluble than the I-PGE, ratios such as Os/Ir, Ru/Ir plotted against Pd/Ir can be used to trace the metasomatic oxidation of mantle samples, mantle-derived magmas and porphyry Cu±Au deposits. This geochemical insight is used to show that Au-rich porphyry Cu deposits are derived from more oxidised mantle wedge than Au-poor porphyry deposits.
DS200612-1492
2006
Janak, M.Vrabec, M., De Hoog, J.C.M., Janak, M.Partial melting of zoisite eclogite and its significance for trace element cycling in subduction zones.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 14. abstract onlyMantleEclogite
DS200712-0226
2007
Janak, M.De Hoog, J.C.M., Janak, M., Vrabec, M.The role of zoisite in trace element distribution in subduction zones.Plates, Plumes, and Paradigms, 1p. abstract p. A211.Mantle, Alps, HimalayasSubduction
DS201312-0436
2013
Janak, M.Janak, M., Krogh Ravna, E.J., Kullerud, K., Yoshida, K., Milovsky, R., Hirajima, T.Discovery of diamond in the Tromso Nappe, Scandinavian Caledonides ( N. Norway).Journal of Metamorphic Geology, Vol. 31, 6, pp. 691-703.Europe, NorwayMicrodiamonds in gneiss
DS201502-0076
2014
Janak, M.Majka, J., Rosen, A., Janak, M., Froitzheim, N., Klonowska, I., Manecki, M., Sasinkova, V., Yoshida, K.Microdiamond discovered in the Seve Nappe ( Scandinavian Caledonides) and its exhumation by the "vacuum-cleaner" mechanism.Geology, Vol. 42, 12, pp. 1107-1110.Europe, SwedenSubduction, microdiamond
DS201503-0156
2015
Janak, M.Kotkova, J., Janak, M.UHP kyanite eclogite associated with garnet peridotite and diamond bearing granulite, northern Bohemian Massif.Lithos, Vol. 226, pp. 255-264.EuropeBohemian
DS201504-0203
2015
Janak, M.Janak, M., Froitzheim, N., Yoshida, K., Sasinkova, V., Nosko, M., Kobayashi,T., Hirajima, T., Vrabec, M.Diamond in metasedimentary crustal rocks from Pohorje, eastern Alps: a window to deep continental subductionJournal of Metamorphic Geology, Vol. 33, 5, pp. 495-512.Europe, SloveniaSubduction
DS201505-0237
2014
Janak, M.Majka, J., Rosen, A., Janak, M., Froitzheim, N., Klonowska, I., Maneck, M., Sasinkova, V., Yoshida, K.Microdiamond discovered in the Seve Nappe (Scandinavian Caledonides) and its exhumation by the "vacuum-cleaner" mechanism.Geology, Vol. 42, 12, pp. 1107-110.EuropeMicrodiamonds
DS201602-0230
2016
Janak, M.Petrik, I., Janak, M., Froitzheim, N., Georgiev, N., Yoshida, K., Sasinkova, V., Konecny, P., Milovska, S.Triassic to Early Jurassic (c.200 Ma) UHP metamorphism in the Central Rhodopes: evidence from U-Pb-Th dating of monazite in diamond bearing gneiss from Chelelpare, Bulgaria.Journal of Metamorphic Geology, in press available, 44p.Europe, BulgariaGneiss - diamonds

Abstract: Evidence for ultrahigh-pressure metamorphism (UHPM) in the Rhodope Metamorphic Complex comes from occurrence of diamond in pelitic gneisses, variably overprinted by granulite facies metamorphism, known from several areas of the Rhodopes. However, tectonic setting and timing of UHPM are not interpreted unanimously. Linking age to metamorphic stage is a prerequisite for reconstruction of these processes. Here we use monazite in diamond-bearing gneiss from Chepelare (Bulgaria) to date the diamond-forming UHPM event in the Central Rhodopes. The diamond-bearing gneiss comes from a strongly deformed, lithologically heterogeneous zone (Chepelare Mélange) sandwiched between two migmatized orthogneiss units, known as Arda-I and Arda-II. Diamond, identified by Raman micro-spectroscopy, shows the characteristic band mostly centred between 1332 and 1330 cm?1. The microdiamond occurs as single grains or polyphase diamond + carbonate inclusions, rarely with CO2. Thermodynamic modelling shows that garnet was stable at UHP conditions of 3.5-4.6 GPa and 700-800 °C, in the stability field of diamond, and was re-equilibrated at granulite facies/partial melting conditions of 0.8-1.2 GPa and 750-800 °C. The texture of monazite shows older central parts and extensive younger domains which formed due to metasomatic replacement in solid residue and/or overgrowth in melt domains. The monazite core compositions, with distinctly lower Y, Th and U contents, suggest its formation in equilibrium with garnet. The U-Th-Pb dating of monazite using electron microprobe analysis yielded a c. 200 Ma age for the older cores with low Th, Y, U and high La/Nd ratio, and a c. 160 Ma age for the dominant younger monazite enriched in Th, Y, U and HREE. The older age of around 200 Ma is interpreted as the timing of UHPM whereas the younger age of around 160 Ma as granulite facies/partial melting overprint. Our results suggest that UHPM occurred in Late Triassic to Early Jurassic time, in the framework of collision and subduction of continental crust after the closure of Palaeotethys.
DS201604-0621
2016
Janak, M.Petrik, I., Janak, M., Froitzheim, N., Georgiev, N., Yoshida, K., Sasinkova, V., Konecny, P., Milovska, S.Triassic to Early Jurassic ( c. 200Ma) UHP metamorphism in the Central Rhodopes: evidence from U-Pb dating of monazite in diamond bearing gneiss from Chepelare ( Bulgaria).Journal of Metamorphic Geology, Vol. 34, 3, pp. 265-291.Europe, BulgariaUHP diamond bearing gneiss
DS201606-1105
2016
Janak, M.Petrik, I., Janak, M., Froitzheim, N., Georgiev, N., Yoshida, K., Sasinkova, V., Konecny, P., Milovska, S.Triassic to Early Jurassic ( c. 200Ma) UHP metamorphism in the central Rhodopes: evidence from U-Pb-Th dating of monazite in diamond bearing gneiss from Chepelare Bulgaria.Journal of Metamorphic Geology, Vol. 34, 3, pp. 265-291.Europe, BulgariaDiamonds in gneiss
DS201702-0221
2017
Janak, M.Klonowska, I., Janak, M., Majka, J., Petrik, I., Froitzheim, N., Gee, D.G., sasinkova, V.Microdiamond on Areskutan confirms regional UHP metamorphism in the Seve Nappe complex of the Scandinavian Caledonides.Journal of Metamorphic Geology, in press availableEurope, Sweden, NorwayUHP

Abstract: Metamorphic diamond in crustal rocks provides important information on the deep subduction of continental crust. Here we present a new occurrence of diamond within the Seve Nappe Complex of the Scandinavian Caledonides, on Åreskutan in Jämtland County, Sweden. Microdiamond is found in-situ as single and composite (diamond + carbonate) inclusions within garnet, in kyanite-bearing paragneisses. The rocks preserve the primary peak pressure assemblage of Ca,Mg-rich garnet + phengite + kyanite + rutile, with polycrystalline quartz surrounded by radial cracks indicating breakdown of coesite. Calculated P-T conditions for this stage are 830-840 °C and 4.1-4.2 GPa, in the diamond stability field. The ultrahigh-pressure (UHP) assemblage has been variably overprinted under granulite facies conditions of 850-860 °C and 1.0-1.1 GPa, leading to formation of Ca,Mg-poor garnet+biotite+ plagioclase+K-feldspar+sillimanite+ilmenite+quartz. This overprint was the result of nearly isothermal decompression, which is corroborated by Ti-in-quartz thermometry. Chemical Th-U-Pb dating of monazite yields ages between 445 and 435 Ma, which are interpreted to record post-UHP exhumation of the diamond-bearing rocks. The new discovery of microdiamond on Åreskutan, together with other evidence of ultrahigh-pressure metamorphism (UHPM) within gneisses, eclogites and peridotites elsewhere in the Seve Nappe Complex, provide compelling arguments for regional (at least 200 km along strike of the unit). UHPM of substantial parts of this far-travelled allochthon. The occurrence of UHPM in both rheologically weak (gneisses) and strong lithologies (eclogites, peridotites) speaks against the presence of large tectonic overpressure during metamorphism.
DS201703-0422
2017
Janak, M.Klonowska, I., Janak, M., Majka, J., Petrik, I., Froitzheim, N., Gee, D.G., Sasinkova, V.Microdiamond on Areskutan confirms regional UHP metamorphism in the Seve Nappe Complex of the Scandinavian Caledonides.Journal of Metamorphic Geology, in press availableEurope, SwedenMicrodiamond

Abstract: Metamorphic diamond in crustal rocks provides important information on the deep subduction of continental crust. Here, we present a new occurrence of diamond within the Seve Nappe Complex (SNC) of the Scandinavian Caledonides, on Åreskutan in Jämtland County, Sweden. Microdiamond is found in situ as single and composite (diamond+carbonate) inclusions within garnet, in kyanite-bearing paragneisses. The rocks preserve the primary peak pressure assemblage of Ca,Mg-rich garnet+phengite+kyanite+rutile, with polycrystalline quartz surrounded by radial cracks indicating breakdown of coesite. Calculated P-T conditions for this stage are 830-840 °C and 4.1-4.2 GPa, in the diamond stability field. The ultrahigh-pressure (UHP) assemblage has been variably overprinted under granulite facies conditions of 850-860 °C and 1.0-1.1 GPa, leading to formation of Ca,Mg-poor garnet+biotite+plagioclase+K-feldspar+sillimanite+ilmenite+quartz. This overprint was the result of nearly isothermal decompression, which is corroborated by Ti-in-quartz thermometry. Chemical Th-U-Pb dating of monazite yields ages between 445 and 435 Ma, which are interpreted to record post-UHP exhumation of the diamond-bearing rocks. The new discovery of microdiamond on Åreskutan, together with other evidence of ultrahigh-pressure metamorphism (UHPM) within gneisses, eclogites and peridotites elsewhere in the SNC, provide compelling arguments for regional (at least 200 km along strike of the unit) UHPM of substantial parts of this far-travelled allochthon. The occurrence of UHPM in both rheologically weak (gneisses) and strong lithologies (eclogites, peridotites) speaks against the presence of large tectonic overpressure during metamorphism.
DS201707-1340
2017
Janak, M.Klonowska, I., Janak, M., Majka, J., Petrik, I., Froitzheim, N., Gee, D.Microdiamond on Areskutan confirms UHP metamorphism in the Seve Nappe Complex of the Scandinavian Caledonides.Journal of Metamorphic Geology, Vol. 35, 5, pp. 541-564.Europe, SwedenUHP

Abstract: Metamorphic diamond in crustal rocks provides important information on the deep subduction of continental crust. Here we present a new occurrence of diamond within the Seve Nappe Complex of the Scandinavian Caledonides, on Åreskutan in Jämtland County, Sweden. Microdiamond is found in-situ as single and composite (diamond + carbonate) inclusions within garnet, in kyanite-bearing paragneisses. The rocks preserve the primary peak pressure assemblage of Ca,Mg-rich garnet + phengite + kyanite + rutile, with polycrystalline quartz surrounded by radial cracks indicating breakdown of coesite. Calculated P-T conditions for this stage are 830-840 ºC and 4.1-4.2 GPa, in the diamond stability field. The ultrahigh-pressure (UHP) assemblage has been variably overprinted under granulite facies conditions of 850-860 ºC and 1.0-1.1 GPa, leading to formation of Ca,Mg-poor garnet + biotite + plagioclase + K-feldspar + sillimanite + ilmenite + quartz. This overprint was the result of nearly isothermal decompression, which is corroborated by Ti-in-quartz thermometry. Chemical Th-U-Pb dating of monazite yields ages between 445 and 435 Ma, which are interpreted to record post-UHP exhumation of the diamond-bearing rocks. The new discovery of microdiamond on Åreskutan, together with other evidence of ultrahigh-pressure metamorphism (UHPM) within gneisses, eclogites and peridotites elsewhere in the Seve Nappe Complex, provide compelling arguments for regional (at least 200 km along the unit) UHPM of substantial parts of this far-travelled allochthon. The occurrence of UHPM in both rheologically weak (gneisses) and strong lithologies (eclogites, peridotites) speaks against the presence of large tectonic overpressure during metamorphism.
DS201805-0973
2017
Janak, M.Ravna, E.K., Zozulya, D., Kullerud, K., Corfu, F., Nabelek, P.I., Janak, M., Slagstad, T., Davidsen, B., Selbekk, R.S., Schertl, H-P.Deep seated carbonatite intrusion and metasomatism in the UHP Tromso Nappe, northern Scandinavian Caledonides - a natural example of generation of carbonatite from carbonated eclogite.Journal of Petrology, Vol. 58, 12, pp. 2403-2428.Europe, Sweden, Norwaycarbonatite

Abstract: Carbonatites (sensu stricto) are igneous rocks typically associated with continental rifts, being emplaced at relatively shallow crustal levels or as extrusive rocks. Some carbonatites are, however, related to subduction and lithospheric collision zones, but so far no carbonatite has been reported from ultrahigh-pressure (UHP) metamorphic terranes. In this study, we present detailed petrological and geochemical data on carbonatites from the Tromsø Nappe—a UHP metamorphic terrane in the Scandinavian Caledonides. Massive to weakly foliated silicate-rich carbonate rocks, comprising the high-P mineral assemblage of Mg-Fe-calcite?±?Fe-dolomite?+?garnet?+?omphacitic clinopyroxene?+?phlogopite?+?apatite?+?rutile?+?ilmenite, are inferred to be carbonatites. They show apparent intrusive relationships to eclogite, garnet pyroxenite, garnet-mica gneiss, foliated calc-silicate marble and massive marble. Large grains of omphacitic pyroxene and megacrysts (up to 5?cm across) of Cr-diopside in the carbonatite contain rods of phlogopite oriented parallel to the c-axis, the density of rods being highest in the central part of the megacrysts. Garnet contains numerous inclusions of all the other phases of the carbonatite, and, in places, composite polyphase inclusions. Zircon, monazite and allanite are common accessory phases. Locally, veins of silicate-poor carbonatite (up to 10?cm across) occur. Extensive fenitization by K-rich fluids, with enrichment in phlogopite along contacts between carbonatite and silicate country rocks, is common. Primitive mantle-normalized incompatible element patterns for the carbonatite document a strong enrichment of light rare earth elements, Ba and Rb, and negative anomalies in Th, Nb, Ta, Zr and Hf. The carbon and oxygen isotope compositions of the carbonatite are distinctly different from those of the spatially associated calc-silicate marble, but also from mantle-derived carbonatites elsewhere. Neodymium and Sr isotope data coupled with the trace element distribution indicate a similarity of the Tromsø carbonatite to orogenic (off-craton) carbonatites rather than to anorogenic (on-craton) ones. U-Pb dating of relatively U-rich prismatic, oscillatory-zoned zircon gives an age of 454•5?±?1•1?Ma. We suggest that the primary carbonatite magma resulted from partial melting of a carbonated eclogite at UHP, in a deeply subducted continental slab.
DS1994-1911
1994
Janardhan, A.S.Wickham, S.M., Janardhan, A.S., Stern, R.J.Regional carbonate alteration of the crust by mantle derived magmaticfluids, Tamil Nadu, South India.Journal of Geology, Vol. 102, No. 4, July, pp. 379-398.IndiaCarbonatite
DS201703-0396
2017
Janasi, V.A.Almeida, V.V., Janasi, V.A., Heaman, L.M., Shaulis, B.J., Hollanda, M.H.B.M., Renne, P.R.Contemporaneous alkaline and tholeiitic magmatism in the Ponta Grossa Arch, Parana Etendeka magmatic province: constraints from U-Pb zircon baddeleyite and 40Ar/39Ar phlogopite dating of the Jose Fernandes gabbro and mafic dykes.Journal of Volcanology and Geothermal Research, in press available 11p.South America, BrazilAlkaline rocks

Abstract: We report the first high-precision ID-TIMS U-Pb baddeleyite/zircon and 40Ar/39Ar step-heating phlogopite age data for diabase and lamprophyre dykes and a mafic intrusion (José Fernandes Gabbro) located within the Ponta Grossa Arch, Brazil, in order to constrain the temporal evolution between Early Cretaceous tholeiitic and alkaline magmatism of the Paraná-Etendeka Magmatic Province. U-Pb dates from chemically abraded zircon data yielded the best estimate for the emplacement ages of a high Ti-P-Sr basaltic dyke (133.9 ± 0.2 Ma), a dyke with basaltic andesite composition (133.4 ± 0.2 Ma) and the José Fernandes Gabbro (134.5 ± 0.1 Ma). A 40Ar/39Ar phlogopite step-heating age of 133.7 ± 0.1 Ma from a lamprophyre dyke is identical within error to the U-Pb age of the diabase dykes, indicating that tholeiitic and alkaline magmatism were coeval in the Ponta Grossa Arch. Although nearly all analysed fractions are concordant and show low analytical uncertainties (± 0.3-0.9 Ma for baddeleyite; 0.1-0.4 Ma for zircon; 2?), Pb loss is observed in all baddeleyite fractions and in some initial zircon fractions not submitted to the most extreme chemical abrasion treatment. The resulting age spread may reflect intense and continued magmatic activity in the Ponta Grossa Arch.
DS201412-0612
2014
Janasi, V.de A.Nannini, F., Janasi, V.de A.Prospeccao de depositos primarios de diamante por tomografia sismica: uma prosposta de integracao entre geologia e geofisica.6 Simposio Brasileiro de Geologia do Diamante, Aug. 3-7, 4p. AbstractSouth America, BrazilGeophysics - seismics
DS201709-2018
2017
Janek, M.Klonowska, I., Janek, M., Majka, J., Petrik, I., Froitzheim, N., Gee, D.G., Sasinkova, V.Microdiamond on Areskutan confirms regional UHP metamorphism in the Seve Nappe Complex of the Scandinavian Caledonides.Journal of Metamorphic Geology, Vol. 35, 5, pp. 541-564.Europe, Scandinaviamicrodiamond

Abstract: Metamorphic diamond in crustal rocks provides important information on the deep subduction of continental crust. Here, we present a new occurrence of diamond within the Seve Nappe Complex (SNC) of the Scandinavian Caledonides, on Åreskutan in Jämtland County, Sweden. Microdiamond is found in situ as single and composite (diamond+carbonate) inclusions within garnet, in kyanite-bearing paragneisses. The rocks preserve the primary peak pressure assemblage of Ca,Mg-rich garnet+phengite+kyanite+rutile, with polycrystalline quartz surrounded by radial cracks indicating breakdown of coesite. Calculated P–T conditions for this stage are 830–840 °C and 4.1–4.2 GPa, in the diamond stability field. The ultrahigh-pressure (UHP) assemblage has been variably overprinted under granulite facies conditions of 850–860 °C and 1.0–1.1 GPa, leading to formation of Ca,Mg-poor garnet+biotite+plagioclase+K-feldspar+sillimanite+ilmenite+quartz. This overprint was the result of nearly isothermal decompression, which is corroborated by Ti-in-quartz thermometry. Chemical Th–U–Pb dating of monazite yields ages between 445 and 435 Ma, which are interpreted to record post-UHP exhumation of the diamond-bearing rocks. The new discovery of microdiamond on Åreskutan, together with other evidence of ultrahigh-pressure metamorphism (UHPM) within gneisses, eclogites and peridotites elsewhere in the SNC, provide compelling arguments for regional (at least 200 km along strike of the unit) UHPM of substantial parts of this far-travelled allochthon. The occurrence of UHPM in both rheologically weak (gneisses) and strong lithologies (eclogites, peridotites) speaks against the presence of large tectonic overpressure during metamorphism.
DS1986-0230
1986
Janes, D.Fahrig, W.F., Christie, K.W., Chown, E.H., Janes, D., Machado, N.The tectonic significance of some basic dyke swarms in the Canadian Superior province with special reference to The geochemistry and paleomagnetism of thCanadian Journal of Earth Sciences, Vol. 23, No. 2, February pp. 238-253Ontario, QuebecTectonics, Dyke
DS1994-0827
1994
Janes, T.Janes, T.northwest Territories diamonds project: developmentThe Canadian Institute of Mining, Metallurgy and Petroleum (CIM) District 6, Oct. 11-15th. Vancouver, 9p.Northwest TerritoriesManagement, Project -sampling, development
DS1994-1805
1994
Janes, T.Turner, B., Janes, T.The BHP/ Dia Met joint venture, Northwest TerritoriesThe Canadian Institute of Mining, Metallurgy and Petroleum (CIM) Section Meeting Oct. 12, Vancouver, p. 66. abstractNorthwest TerritoriesUpdate, BHP, Dia Met
DS202203-0350
2022
Jang, B.G.He, Y., Sun, S., Kim, D.Y., Jang, B.G., Li, H., Mao, H-K.Superionic iron alloys and their seismic velocities in Earth's inner core.Nature, Vol. 602, pp. 258-276. 18p.Mantlecore

Abstract: Earth’s inner core (IC) is less dense than pure iron, indicating the existence of light elements within it1. Silicon, sulfur, carbon, oxygen and hydrogen have been suggested to be the candidates2,3, and the properties of iron-light-element alloys have been studied to constrain the IC composition4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19. Light elements have a substantial influence on the seismic velocities4,5,6,7,8,9,10,11,12,13, the melting temperatures14,15,16,17 and the thermal conductivities18,19 of iron alloys. However, the state of the light elements in the IC is rarely considered. Here, using ab initio molecular dynamics simulations, we find that hydrogen, oxygen and carbon in hexagonal close-packed iron transform to a superionic state under the IC conditions, showing high diffusion coefficients like a liquid. This suggests that the IC can be in a superionic state rather than a normal solid state. The liquid-like light elements lead to a substantial reduction in the seismic velocities, which approach the seismological observations of the IC20,21. The substantial decrease in shear-wave velocity provides an explanation for the soft IC21. In addition, the light-element convection has a potential influence on the IC seismological structure and magnetic field.
DS1993-1814
1993
Jang, J.Zhao, D., Smith, D.G.W. Smith, Zhou, M., Jang, J., Deng, C., Huang, Y.Yinniugou lamproites in Datong, northern Shanxi Province, Chin a: first occurrence in the North Chin a craton.Mid-continent diamonds Geological Association of Canada (GAC)-Mineralogical Association of Canada (MAC) Symposium ABSTRACT volume, held Edmonton May, pp. 133-140.ChinaLamproite, Craton, tectonics
DS200712-0482
2007
Jang, Y-H.Jang, Y-H., Jiang, S-Y., LHou, M-L., Ling, H.F., Zhao, K., Ni, P.Geochemistry of Late Mesozoic lamprophyre dikes from the eastern North Chin a Craton: implications for subcontinental lithosphere evolution.Plates, Plumes, and Paradigms, 1p. abstract p. A445.ChinaLamprophyre
DS200712-0738
2007
Jang-Green, H.Moe, K.S., Johnson, P., Jang-Green, H.Translucent greenish yellow diamonds.Gems & Gemology, Vol. 43, 1, pp. 50-53.TechnologyDiamond morphology
DS1998-0682
1998
Janiak, J.Janiak, J.Envi-Tech microdiamond recovery adsorption process for economic evaluation of diamond deposit.Calgary Mining Forum, Apr. 8-9, p. 67-8. poster abstractNorthwest Territories, SaskatchewanLamproite, Sampling - DRAP process
DS200712-0088
2006
Janik, T.Bogdanova, S., Gorbatschev, R., Grad, M., Janik, T., Guterch, A., Kozlovskaya, E., Motuza, G., SkridaiteEUROBRIDGE: new insight into the geodynamic evolution of the East European Craton.Geological Society of London Memoir, No. 32, pp. 599-626.EuropeCraton
DS200712-0483
2007
Janik, T.Janik, T., Kozlovskaya, E., Yliniemi, J.Crust mantle boundary in the central Fennoscandian shield: constraints from wide angle P and S wave velocity models and new results of reflection profiling in FinlandJournal of Geophysical Research, Vol. 112, B4, B04302.Europe, FinlandGeophysics - seismics
DS200912-0334
2009
Janik, T.Janik, T., Kozlovskaya, E., Helikkinen, P., Tliniemi, J.Evidence for preservation of crustal root beneath the Proterozoic Lapland-Kola orogen ( northern Fennoscandian shield) derived from P and S wave models.Journal of Geophysical Research, Vol. 114. B 6, B06308.Europe, Finland, Kola PeninsulaGeophysics - seismics
DS202009-1671
2020
Janik, T.Tiira, T., Janik, T., Skrzynik, T., Komminaho, K., Heinonen, A., Veikkolainen, T., Vakeva, S., Korja, A.Full scale crustal interpretation of Kokkola-Kymi ( KOKKY) seismic profile, Fennoscandian shield.Pure and Applied Geophysics, Vol. 177, 8, pp. 3775-3795. pdfEurope, Finlandgeophysics - seismics

Abstract: The Kokkola-Kymi Deep Seismic Sounding profile crosses the Fennoscandian Shield in northwest-southeast (NW-SE) direction from Bothnian belt to Wiborg rapakivi batholith through Central Finland granitoid complex (CFGC). The 490-km refraction seismic line is perpendicular to the orogenic strike in Central Finland and entirely based on data from quarry blasts and road construction sites in years 2012 and 2013. The campaign resulted in 63 usable seismic record sections. The average perpendicular distance between these and the profile was 14 km. Tomographic velocity models were computed with JIVE3D program. The velocity fields of the tomographic models were used as starting points in the ray tracing modelling. Based on collected seismic sections a layer-cake model was prepared with the ray tracing package SEIS83. Along the profile, upper crust has an average thickness of 22 km average, and P-wave velocities (Vp) of 5.9-6.2 km/s near the surface, increasing downward to 6.25-6.40 km/s. The thickness of middle crust is 14 km below CFGC, 20 km in SE and 25 km in NW, but Vp ranges from 6.6 to 6.9 km/s in all parts. Lower crust has Vp values of 7.35-7.4 km/s and lithospheric mantle 8.2-8.25 km/s. Moho depth is 54 km in NW part, 63 km in the middle and 43 km in SW, yet a 55-km long section in the middle does not reveal an obvious Moho reflection. S-wave velocities vary from 3.4 km/s near the surface to 4.85 km/s in upper mantle, consistently with P-wave velocity variations. Results confirm the previously assumed high-velocity lower crust and depression of Moho in central Finland.
DS1997-0551
1997
Jankovic, S.Jankovic, S.The Carpatho-Balkanides and adjacent area: a sector of the Tethyan Eurasian metallogenic beltMineralium Deposita, Vol. 32, No. 5, pp. 426-433GlobalMetallogeny, genesis, model, Ore deposits, tectonic setting
DS1860-0315
1879
Jannetaz, E.Jannetaz, E.Sur les Colorations de Diamant dans la Lumiere PolariseeSoc. Min. France (paris) Bulletin., Vol. 2, P. 124.GlobalDiamond crystallography
DS1860-0316
1879
Jannetaz, E.Jannetaz, E.Observations sur la Communique de M. ChaperSoc. Min. France (paris) Bulletin., Vol. 2, PP. 200-201.Africa, Africa, South Africa, Griqualand WestDiamond crystallography
DS1860-0385
1882
Jannetaz, E.Jannetaz, E.Analyse D'un Pyroxene Vert des Mines Diamantiferes du CapSoc. Min. France (paris) Bulletin., Vol. 5, P. 281.Africa, South Africa, Cape ProvinceDiamond Mineralogy
DS1860-0469
1885
Jannetaz, E.Jannetaz, E.Note sur Un Diamant du CapSoc. Min. France (paris) Bulletin., Vol. 8, PP. 42-43.Africa, South AfricaDiamond crystallography
DS1860-0367
1881
Jannettaz, E.Jannettaz, E., Fontenay, E., Vanderheym, E., Coutance, A.Diamant et Pierres Precieuses. Cristall. Descript. Emplois, evaluation.Paris:, 580P. SECOND EDITION.GlobalGemology
DS2000-0139
2000
JanneyCarlson, R.W., Janney, Shirey, Boyd, Pearson, IrvineChemical and age structure of the southern African lithospheric mantle: implications continent formationGeological Society of America (GSA) Abstracts, Vol. 32, No. 7, p.A-163.South AfricaMantle xenoliths - Kaapvaal Craton, Geophysics - seismics
DS201012-0321
2010
Janney, P.Janney, P., Bell, D.Pb isotope evidence of a cognate origin for Cr poor megacrysts in southern African kimberlites.Goldschmidt 2010 abstracts, posterAfrica, South AfricaGeochronology
DS201607-1354
2016
Janney, P.Janney, P.A hidden mantle reservoir in the continental lithosphere? Evidence from Hf-Sr-Nd-Pb isotopes in megacrysts and kimberlites.IGC 35th., Session A Dynamic Earth 1p. AbstractMantleKimberlite
DS201607-1381
2016
Janney, P.Tappe, S., Griffin, W., Janney, P., Arndt, N., Gurney, J.The dynamic Earth and its kimberlite, cratonic mantle and diamond record through time.IGC 35th., Session A Dynamic Earth 1p. AbstractMantleKimberlite
DS201708-1680
2017
Janney, P.Janney, P.Hidden reservoirs in the continental lithosphere? Evidence from Hf-Sr-Nd-Pb isotopes in southern African kimberlite megacrysts.11th. International Kimberlite Conference, OralAfrica, Southern Africageochronology
DS201708-1681
2017
Janney, P.Janney, P.Geochemistry of the Namaqualand, Busmanland and Warmbad melillitite and kimberlite provinces of South Africa and Namibia: the southern extension of the African kimberlitic megalineament.11th. International Kimberlite Conference, PosterAfrica, South Africa, Namibiageochemistry, lineament
DS201810-2315
2018
Janney, P.Fitzpayne, A., Giuliani, A., Hergt, J., Phillips, D., Janney, P.New geochemical constraints on the origins of MARID and PIC rocks: implications for mantle metasomatism and mantle -derived potassic magmatism.Lithos, Vol. 318-319, pp. 478-493.Mantlemetasomatism
DS201812-2809
2018
Janney, P.Fitzpayne, A., Giuliani, A., Hergt, J., Phillips, D., Janney, P.New geochemical constraints on the origins of MARID and PIC rocks: implications for mantle metasomatism and mantle derived potassic magmatism. ( kimberlite)Lithos, Vol. 318-319, pp. 478-493.Globallamproites

Abstract: MARID (Mica-Amphibole-Rutile-Ilmenite-Diopside) and PIC (Phlogopite-Ilmenite-Clinopyroxene) rocks are unusual mantle samples entrained by kimberlites and other alkaline volcanic rocks. The formation of MARID rocks remains hotly debated. Although the incompatible element (for example, large ion lithophile element) enrichment in these rocks suggests that they formed by mantle metasomatism, the layered textures of some MARID samples (and MARID veins in composite xenoliths) are more indicative of formation by magmatic processes. MARID lithologies have also been implicated as an important source component in the genesis of intraplate ultramafic potassic magmas (e.g., lamproites, orangeites, ultramafic lamprophyres), due to similarities in their geochemical and isotopic signatures. To determine the origins of MARID and PIC xenoliths and to understand how they relate to alkaline magmatism, this study presents new mineral major and trace element data and bulk-rock reconstructions for 26 MARID and PIC samples from the Kimberley-Barkly West area in South Africa. Similarities between compositions of PIC minerals and corresponding phases in metasomatised mantle peridotites are indicative of PIC formation by pervasive metasomatic alteration of peridotites. MARID genesis remains a complicated issue, with no definitive evidence precluding either the magmatic or metasomatic model. MARID minerals exhibit broad ranges in Mg# (e.g., clinopyroxene Mg# from 82 to 91), which may be indicative of fractionation processes occurring in the MARID-forming fluid/melt. Finally, two quantitative modelling approaches were used to determine the compositions of theoretical melts in equilibrium with MARID rocks. Both models indicate that MARID-derived melts have trace element patterns resembling mantle-derived potassic magma compositions (e.g., lamproites, orangeites, ultramafic lamprophyres), supporting inferences that these magmas may originate from MARID-rich mantle sources.
DS201902-0271
2019
Janney, P.Fitzpayne, A., Giuliani, A., Maas, R., Hergt, J., Janney, P., Phillips, D.Progressive metasomatism of the mantle by kimberlite melts: Sr-Nd-Hf-Pb isotope compositions of MARID and PIC minerals.Earth and Planetary Science Letters, Vol. 506, pp. 15-26.Africa, South Africadeposit - Newlands, Kimberley, Bultfontein

Abstract: MARID (Mica-Amphibole-Rutile-Ilmenite-Diopside) and PIC (Phlogopite-Ilmenite-Clinopyroxene) rocks occur as mantle-derived xenoliths in kimberlites and other alkaline volcanic rocks. Both rock types are alkaline and ultramafic in composition. The H2O and alkali metal enrichments in MARID and PIC rocks, reflected in abundant phlogopite, have been suggested to be caused by extreme mantle metasomatism. Radiogenic (Sr-Nd-Hf-Pb) isotope and trace element compositions for mineral separates from MARID (clinopyroxene and amphibole) and PIC (clinopyroxene only) samples derived from Cretaceous kimberlites (Kimberley) and orangeites (Newlands) from South Africa are used here to examine the source(s) of mantle metasomatism. PIC clinopyroxene is relatively homogeneous, with narrow ranges in initial isotopic composition (calculated to the emplacement age of the host Bultfontein kimberlite; 87Sr/86Sri: 0.7037-0.7041; ?Ndi: +3.0 to +3.6; ?Hfi: +2.2 to +2.5; 206Pb/204Pbi: 19.72-19.94) similar to kimberlite values. This is consistent with PIC rocks representing peridotites modified by intense metasomatic interaction with kimberlite melts. The MARID clinopyroxene and amphibole separates () studied here display broader ranges in isotope composition (e.g., 87Sr/86Sri: 0.705-0.711; ?Ndi: ?11.0 to ?1.0; ?Hfi: ?17.9 to ?8.5; 206Pb/204Pbi: 17.33-18.72) than observed in previous studies of MARID rocks. The Nd-Hf isotope compositions of kimberlite-derived MARID samples fall below the mantle array (??Hfi between ?13.0 and ?2.4), a feature reported widely for kimberlites and other alkaline magmas. We propose that such displacements in MARID minerals result from metasomatic alteration of an initial “enriched mantle” MARID composition (i.e., 87Sr/86Sri = 0.711; ?Ndi = ?11.0; ?Hfi = ?17.9; and 206Pb/204Pbi = 17.3) by the entraining kimberlite magma (87Sr/86Sr; ?Nd; ?Hf; 206Pb/204Pb). A model simulating the flow of kimberlite magma through a mantle column, thereby gradually equilibrating the isotopic and chemical compositions of the MARID wall-rock with those of the kimberlite magma, broadly reproduces the Sr-Nd-Hf-Pb isotope compositions of the MARID minerals analysed here. This model also suggests that assimilation of MARID components could be responsible for negative ??Hfi values in kimberlites. The isotopic composition of the inferred initial MARID end-member, with high 87Sr/86Sr and low ?Nd, ?Hf, and 206Pb/204Pb, resembles those found in orangeites, supporting previous inferences of a genetic link between MARID-veined mantle and orangeites. The metasomatic agent that produced such compositions in MARID rocks must be more extreme than the EM-II mantle component and may relate to recycled material that experienced long-term storage in the lithospheric mantle.
DS201910-2257
2019
Janney, P.Fitzpayne, A., Giuliani, A., Maas, R., Hergt, J., Janney, P., Phillips, D.Progressive metasomatism of the mantle by kimberliitic melts: Sr-Nd-Hf-Pb isotopic composition of MARID and PIC minerals.Goldschmidt2019, 1p. AbstractMantlemetasomatism

Abstract: MARID (Mica-Amphibole-Rutile-Ilmenite-Diopside) and PIC (Phlogopite-Ilmenite-Clinopyroxene) rocks occur as mantle-derived xenoliths in kimberlites and other alkaline volcanic rocks. Both rock types are alkaline and ultramafic in composition. The H2O and alkali metal enrichments in MARID and PIC rocks, reflected in abundant phlogopite, have been suggested to be caused by extreme mantle metasomatism. Radiogenic (Sr-Nd-Hf-Pb) isotope and trace element compositions for mineral separates from MARID (clinopyroxene and amphibole) and PIC (clinopyroxene only) samples derived from Cretaceous kimberlites (Kimberley) and orangeites (Newlands) from South Africa are used here to examine the source(s) of mantle metasomatism. PIC clinopyroxene ( n = 4 ) is relatively homogeneous, with narrow ranges in initial isotopic composition (calculated to the emplacement age of the host Bultfontein kimberlite; 87Sr/86Sri: 0.7037-0.7041; ?Ndi: +3.0 to +3.6; ?Hfi: +2.2 to +2.5; 206Pb/204Pbi: 19.72-19.94) similar to kimberlite values. This is consistent with PIC rocks representing peridotites modified by intense metasomatic interaction with kimberlite melts. The MARID clinopyroxene ( n = 9 ) and amphibole separates ( n = 11 ) studied here display broader ranges in isotope composition (e.g., 87Sr/86Sri: 0.705-0.711; ?Ndi: ?11.0 to ?1.0; ?Hfi: ?17.9 to ?8.5; 206Pb/204Pbi: 17.33-18.72) than observed in previous studies of MARID rocks. The Nd-Hf isotope compositions of kimberlite-derived MARID samples fall below the mantle array (??Hfi between ?13.0 and ?2.4), a feature reported widely for kimberlites and other alkaline magmas. We propose that such displacements in MARID minerals result from metasomatic alteration of an initial “enriched mantle” MARID composition (i.e., 87Sr/86Sri = 0.711; ?Ndi = ?11.0; ?Hfi = ?17.9; and 206Pb/204Pbi = 17.3) by the entraining kimberlite magma (87Sr/86Sr ? i 0.704 ; ?Nd ? i + 3.3 ; ?Hf ? i + 2.3 ; 206Pb/204Pb ? i 19.7 ). A model simulating the flow of kimberlite magma through a mantle column, thereby gradually equilibrating the isotopic and chemical compositions of the MARID wall-rock with those of the kimberlite magma, broadly reproduces the Sr-Nd-Hf-Pb isotope compositions of the MARID minerals analysed here. This model also suggests that assimilation of MARID components could be responsible for negative ??Hfi values in kimberlites. The isotopic composition of the inferred initial MARID end-member, with high 87Sr/86Sr and low ?Nd, ?Hf, and 206Pb/204Pb, resembles those found in orangeites, supporting previous inferences of a genetic link between MARID-veined mantle and orangeites. The metasomatic agent that produced such compositions in MARID rocks must be more extreme than the EM-II mantle component and may relate to recycled material that experienced long-term storage in the lithospheric mantle.
DS1998-0683
1998
Janney, P.E.Janney, P.E., Le Roex, A.P.Causes of compositional diversity in the olivine melilitites of Namaqualand- Bushmanland.7th International Kimberlite Conference Abstract, pp. 371-3.South AfricaMelilitites, Alkaline diatremes
DS1998-0684
1998
Janney, P.E.Janney, P.E., Le Roex, A.P., Viljoen, K.S.Trace element and isotopic characteristics of olivine melilitites from The western Cape: source for Group I.7th International Kimberlite Conference Abstract, pp. 374-6.South Africa, NamaqualandCape Fold Belt, Melilitites, Group I kimberlites
DS2001-0531
2001
Janney, P.E.Janney, P.E., Castillo, P.R.Geochemistry of the oldest Atlantic oceanic crust suggests mantle plume involvement in early history...Earth and Planetary Science Letters, Vol. 192, No. 3, pp. 291-302.Atlantic OceanMantle plume - not specific to diamonds
DS2002-0764
2002
Janney, P.E.Janney, P.E., LeRoex, A.P., Carlson, R.W., Viljoen, K.S.A chemical and multi isotope study of the western Cape olivine melilitite province SouthJournal of Petrology, Vol. 43, 12, pp. 2339-70.South AfricaGeochemistry - HIMU signature, Geochronology
DS2003-0095
2003
Janney, P.E.Bell, D.R., Schmitz, M.D., Janney, P.E.Mesozoic thermal evolution of the southern African mantle lithosphereLithos, Vol. 71, 2-4, pp. 273-87.South AfricaGeothermometry
DS2003-0646
2003
Janney, P.E.Janney, P.E., Le Roex, A.P., Carlson, R.W., Bell, D.R.Os and Hf isotope constraints on the sources of olivine melilitites from western South8 Ikc Www.venuewest.com/8ikc/program.htm, Session 7, POSTER abstractSouth AfricaGeochronology
DS200412-0130
2003
Janney, P.E.Bell, D.R., Schmitz, M.D., Janney, P.E.Mesozoic thermal evolution of the southern African mantle lithosphere.Lithos, Vol. 71, 2-4, pp. 273-87.Africa, South AfricaGeothermometry
DS200412-0903
2003
Janney, P.E.Janney, P.E., Le Roex, A.P., Carlson, R.W., Bell, D.R.Os and Hf isotope constraints on the sources of olivine melilitites from western South Africa.8 IKC Program, Session 7, POSTER abstractAfrica, South AfricaKimberlite petrogenesis Geochronology
DS200512-0220
2005
Janney, P.E.Day, J.M.D., Hilton, D.R., Pearson, D.G., MacPherson, C.G., Kjarsgaard, B.A., Janney, P.E.Absence of a high time integrated 3He (U-Th) source in the mantle beneath continents.Geology, Vol. 33, 9, Sept. pp. 733-736.Mantle, Canada, Africa, South Africa, UgandaGeochronology - helium isotopes
DS201012-0322
2010
Janney, P.E.Janney, P.E., Shirey, S.B., Carlson, R.W., Pearson, D.G., Bell, D.R., Le Roex, A., Ishikawa, Nixon, BoydAge, composition and thermal characteristics of South African off craton mantle lithosphere: evidence for a multi stage history.Journal of Petrology, Vol. 51, 9, pp. 1849-1890,Africa, South AfricaGeochronology, geothermometry
DS201112-0476
2011
Janney, P.E.Janney, P.E., Bell, D.R.Pb Sr Nd Hf isotope variations of megacrysts from Mesozoic Southern African kimberlites reflect mixing of HIMU melts with deep lithosphere.Goldschmidt Conference 2011, abstract p.1102.Africa, South AfricaPofadder, Monastery
DS201412-0173
2014
Janney, P.E.Day, J.M.D., Peters, B.J., Janney, P.E.Oxygen isotope systematics of South African olivine melilitites and implications for HIMU mantle reservoirs.Lithos, Vol. 202-203, pp. 76-84.Africa, South AfricaMelilitite
DS201510-1794
2015
Janney, P.E.Ogungbuyi, P.I., Janney, P.E., Harris, C.The petrogenesis and geochemistry of the Zandkopsdrift carbonatite complex, Namaqualand, South Africa.GSA Annual Meeting, Paper 131-14, 1p. Abstract onlyAfrica, South AfricaCarbonatite

Abstract: Petrologic and geochemical data for carbonatites and associated alkaline igneous rocks are presented for the Zandkopsdrift Carbonatite Complex, Namaqualand. The samples included in this study are relatively fresh, collected by coring at depths of >70 m below the weathered cap zone. The Zandkopsdrift complex is the only locality in the province known to contain significant carbonatite. The carbonatites studied are calico-, ferro- and silico- carbonatites, based on mineralogy, texture, and major element composition. They have low to moderate Mg-numbers (35-65), variable MgO contents (1.2-8.50 wt.%) and high atomic Ca/Ca+Mg (0.73-0.97), indicating that they are not likely simple mantle melts. The carbonatites contain significant apatite, magnetite, pyrochlore and phlogopite. Zandkopsdrift also contains significant amounts of aillikite and olivine melilitite. These rocks have relatively low SiO2 (25-31 wt.%) and Al2O3 (5.3- 6.1 wt.%), high K2O (6-6.3 wt.%) and TiO2 (5.6-9.5 wt.%) and moderate Mg numbers (51-58). ?18O and ?13C isotopes were measured for carbonatites and aillikites. ?13CPDB values are close to those expected for mantle-derived carbonatites (-3.9 to -8.83), while the ?18OSMOW values are significantly higher (+13. 25 to 21.84‰). The high ?18O value observed in carbonatites and aillikites is most likely attributable to secondary alteration by hydrous/hydrothermal fluids. This supports the inference that the Zandkopsdrift carbonatite is magmatic in origin but was later affected by secondary alteration which resulted in the elevated O stable isotopes. The ‘mantle-like’ ?13C is inconsistent with significant assimilation of C-bearing crustal rocks. Chondrite-normalised REE contents in the carbonatites are 2400 to 10,600 for La and 36 to 170 for Lu. The high REE contents of the carbonatites are most likely due to a combination of a source metasomatised by a highly LREE-enriched agent, as well as significant magmatic differentiation. The relatively fractionated composition of the Zandkopsdrift aillikites and melilitites is also consistent with this hypothesis. We propose that the Zandkopsdrift carbonatites were most likely formed by either immiscible liquid separation from or fractional crystallization of a moderately fractionated, carbonate-rich silicate parental magma. Session No. 131--Booth# 338
DS201709-2039
2017
Janney, P.E.Ogungbuyi, P.I., Janney, P.E., Harris, C.The geochemistry and genesis of Marinkas Quellen carbonatite complex, southwestern Namibia.Goldschmidt Conference, abstract 1p.Africa, Namibiacarbonatite

Abstract: The 525 Ma Marinkas Quellen (MQ) Complex of southern Namibia, part of the Kuboos-Bremen Line (KBL) of alkaline igneous centers [1] consists of granites, nepheline syenites and carbonatites and is the only carbonatite locality in the KBL [1]. MQ carbonatite variteties include calciocarbonatites, magnesiocarbonatites and ferrocarbonatites. The enrichments in Ba, Nb and the REE vary widely in the carbonatites, with La ranging from 45 to 11154 ppm. All the carbonatites are characterised by large Zr, Hf, Ti depletions. Zr/Hf ratios ranges from 40 to 500, all greater than the chondritic value of 36. Such large Zr/Hf fractionations are often associated with carbonatite metasomatism. The values of carbon and oxygen isotope ratios of bulk carbonate in Marinkas Quellen carbonatites vary significantly (e.g., ?13C = -3.95 to -6.02‰; ?18 O = 8.84 to 22.22‰). The carbon isotope compositions are in the mantle range, while the oxygen isotope values extend to higher than typical mantle values, presumably due to interaction with hydrous fluids. All but two of the carbonatite samples have initial 87Sr/86Sr ratios falling in the range of 0.70236 to 0.70408. Of the remaining samples, one, a ferrocarbonatite, has a higher value of 0.70503 that is likely due to contamination by the surrounding rock or assimilation in the lower crust or Sr exchange with groundwater. The other, a magnesiocarbonatite, appears to have experienced an increase in its Rb/Sr ratio due to alteration, resulting in an over-corrected initial 87Sr/86Sr value. The relatively low Sr isotope ratios of most samples, plus their HNd(t) values (+3.9 to +4.8) values suggest that the carbonatite magma was generated from a long-lived low Rb/Sr, high Sm/Nd, relatively depleted mantle source. The radiogenic Pb isotope composition of the carbonatites (206Pb/204Pbi ratios from 18.06 to 22.38), suggests a high U/Pb source, akin to the HIMU mantle end member. This points to a sub-lithospheric (asthenospheric) source with only a relatively minor contribution from enriched lithospheric mantle
DS201912-2810
2019
Janney, P.E.Pearson, D.G., Woodhead, J.D., Janney, P.E.Kimberlites as geochemical probes of Earth's mantle.Elements, Vol. 15, 6, pp.Mantlegeochemistry

Abstract: Kimberlites are ultrabasic, Si-undersaturated, low Al, low Na rocks rich in CO2 and H2O. The distinctive geochemical character of kimberlite is strongly influenced by the nature of the local underlying lithospheric mantle. Despite this, incompatible trace element ratios and radiogenic isotope characteristics of kimberlites, filtered for the effects of crustal contamination and alteration, closely resemble rocks derived from the deeper, more primitive, convecting mantle. This suggests that the ultimate magma source is sub-lithospheric. Although the composition of primitive kimberlite melt remains unresolved, kimberlites are likely derived from the convecting mantle, with possible source regions ranging from just below the lithosphere, through the transition zone, to the core-mantle boundary.
DS202107-1118
2021
Janney, P.E.Nkere, B.J., Janney, P.E., Tinguely, C.Cr-poor and Cr-rich clinopyroxene and garnet megacrysts from southern African Group 1 and Group 2 kimberlites: clues to megacrysts origins and their relationship to kimberlites.Lithos, Vol. 396-397, 106231 pdfAfrica, South Africa, Botswanadeposit - Colossus, Orapa, Kalput, Bellsbank

Abstract: Controversies surround the origin of kimberlite megacrysts, including whether and how they are genetically related to their host kimberlites, the relationship between the Cr-poor and Cr-rich suites and the dominant processes responsible for elemental and isotopic variations of megacrysts from a given kimberlite. We present new in-situ major and trace element and Sr isotopic results for clinoyroxene and garnet megacrysts from four southern African kimberlites: Colossus and Orapa (Group 1 kimberlites on the Zimbabwe craton), and Kalkput and Bellsbank (Group 2 kimberlites on the western Kaapvaal craton), that include both Cr-poor and Cr-rich megacryst varieties. Cr-poor megacrysts are present at Colossus, Orapa and Kalkput and the data exhibit tight, well-defined trends on major element diagrams as well as incompatible and rare earth element abundances similar to those previously reported for Cr-poor megacrysts. Cr-rich megacrysts, which are also present at Orapa and are the only variety present at Bellsbank, generally have higher Mg# values, lack well-defined major element trends and show stronger incompatible element enrichments as well as more radiogenic 87Sr/86Sri ratios than Cr-poor megacrysts from the same kimberlite group. Thermobarometry indicates that the Cr-poor megacrysts equilibrated at temperatures of ?1200 to 1450 °C and pressures of 4.5 to 7.5 GPa. Cr-rich megacrysts, in contrast, extend to temperatures and pressures as low as 700 °C and 3 GPa, respectively. This indicates that, in the studied suites, Cr-poor megacrysts equilibrated at high temperatures in the lower lithosphere (>135 km), whereas Cr-rich megacrysts typically equilibrated at lower temperatures and pressures. Within the Cr-poor megacrysts from Group 1 and Group 2 kimberlites, there is a clear correspondence between kimberlite group, diagnostic incompatible element ratios (e.g., Nb/La) and Sr isotope ratios that parallel the differences noted between whole-rock Group 1 and Group 2 kimberlites. In the case of Cr-poor megacrysts, similar calculated melt compositions in equilibrium with garnet and clinopyroxene from the same kimberlite were obtained using recent high-pressure mineral?carbonated melt partition coefficients. This suggests formation in conditions close to trace element equilibrium, and is consistent with crystallization from primitive melts with kimberlite-like trace element compositions. In the case of Cr-rich megacrysts, differences in the compositions of melts in equilibrium with clinopyroxene and garnet tend to be larger, and melts in equilibrium with Cr-rich clinopyroxene tend to show significantly greater incompatible element enrichments than those of estimated near-primary kimberlite melts. This could be due to the different behaviour of clinopyroxene and garnet during metasomatic melt-rock interaction, but the apparent disequilibrium between clinopyroxene and garnet could also be due to some of the Cr-rich megacrysts actually being peridotitic xenocrysts. We propose a model for the origin of southern African megacrysts in which carbonated protokimberlite melts formed stockwork-like bodies of variable size in the deep lithosphere (>130 km), which fed networks of melt-filled veins extending into the surrounding and overlying mantle. Crystallization of larger melt bodies resulted in megacryst assemblages dominated by Cr-poor megacrysts, and the incompatible element and isotopic characteristics of these dominantly reflect those of the protokimberlite melt. In contrast, crystallization of smaller melt bodies and their vein networks resulted in megacryst assemblages dominated by Cr-rich megacrysts, which formed as a result of extensive assimilation and metasomatic melt-rock interaction between protokimberlite and peridotite wallrock at low melt/rock ratios, particularly in the middle to shallow lithosphere where pre-existing potassic metasomatic heterogeneities are prevalent. The Cr-rich nature and enrichments in incompatible elements and radiogenic Sr in the Cr-rich megacrysts reflect extensive interaction of their parental magmas with this metasomatized peridotite.
DS201503-0154
2015
Jannucci, C.King, J., Shigley, J.E., Jannucci, C.Exceptional pink to red diamonds: a celebration of the 30th. Argyle tender.Gems & Gemology, Vol. 50, 4, winter 2014, 15p.AustraliaHistory, review Argyle
DS1995-1010
1995
Janocko, J.Kovac, M., Kovac, P., Janocko, J.The East Slovakian Basin - a complex back arc basinTectonophysics, Vol. 252, No. 1-4, Dec. 30, pp. 453-466GlobalBasin, Back arc
DS200612-0636
2006
Janousek, V.Janousek, V., Farrow, C.M., Erban, V.Interpretation of whole rock geochemical dat a in igneous geochemistry: introducing geochemical Dat a Toolkit (GCDkit).Journal of Petrology, Vol. 47, 6, pp. 1255-1259.TechnologyGeochemical Data Kit
DS201312-0497
2013
Janousek, V.Konopasek, J., Kosler, J., Slama, J., Janousek, V.Timing and sources of pre-collisional NeoProterozoic sedimentation along the SW margin of the Congo Craton, (Kaoko Belt, NW Namibia).Gondwana Research, Vol. 26, 1, pp. 386-401.Africa, NamibiaSedimentology
DS201803-0458
2018
Janousek, V.Konopasek, J., Janousek, V., Oyhantcabal, P., Slama, J., Ulrich, S.Did the circum Rodinia subduction trigger the Neoproterozoic rifting along the Congo Kalahari craton margin?International Journal of Earth Sciences, Vol. 106, 8, pp. 1-36.Africa, Namibiacraton

Abstract: Early Neoproterozoic metaigneous rocks occur in the central part of the Kaoko-Dom Feliciano-Gariep orogenic system along the coasts of the southern Atlantic Ocean. In the Coastal Terrane (Kaoko Belt, Namibia), the bimodal character of the ca. 820-785 Ma magmatic suite and associated sedimentation sourced in the neighbouring pre-Neoproterozoic crust are taken as evidence that the Coastal Terrane formed as the shallow part of a developing back arc/rift. The arc-like chemistry of the bimodal magmas is interpreted as inherited from crustal and/or lithospheric mantle sources that have retained geochemical signature acquired during an older (Mesoproterozoic) subduction-related episode. In contrast, the mantle contribution was small in ca. 800-770 Ma plutonic suites in the Punta del Este Terrane (Dom Feliciano Belt, Uruguay) and in southern Brazil; still, the arc-like geochemistry of the prevalent felsic rocks seems inherited from their crustal sources. The within-plate geochemistry of a subsequent, ca. 740-710 Ma syn-sedimentary volcanism reflects the ongoing crustal stretching and sedimentation on top of the Congo and Kalahari cratons. The Punta del Este-Coastal Terrane is interpreted as an axial part of a Neoproterozoic “Adamastor Rift”. Its opening started in a back-arc position of a long-lasting subduction system at the edge of a continent that fragmented into the Nico Pérez-Luís Alves Terrane and the Congo and Kalahari cratons. The continent had to be facing an open ocean and consequently could not be located in the interior of the Rodinia. Nevertheless, the early opening of the Adamastor Rift coincided with the lifetime of the circum-Rodinia subduction system.
DS200712-0484
2007
Janse, A.Janse, A.Global rough diamond production since 1870. Annual production by country, by value, types of deposits, major mines, contemporary production.Gems & Gemology, Vol. 43, 2, pp. 98-119.GlobalDiamond production
DS201112-0477
2011
Janse, A.J.AJanse, A.J.A, BramMystery diamonds - from alluvial deposits.GIA International Symposium 2011, Gems & Gemology, Summer abstract p. 110.GlobalAlluvials
DS1960-0255
1962
Janse, A.J.A.Janse, A.J.A.Geology and Petrology of the Gibeon Kimberlite Province And the Gross Brukkaros Mountain.Leeds University Research Institute of African Geology Annual Report, Vol. 6, PP. 18-20.Southwest Africa, NamibiaKimberlite Mineralogy, Petrology
DS1960-0358
1963
Janse, A.J.A.Janse, A.J.A.Progress Report on the Geology and Petrology of the Gibeon kimberlite Province and the Gross Brukkaros Mountain.Leeds University Research Institute of African Geology Annual Report, Vol. 7, PP. 17-19.Southwest Africa, NamibiaGeology, Kimberlite Mineralogy, Petrology
DS1960-0462
1964
Janse, A.J.A.Janse, A.J.A.Monticellite Peridotite from Mount Brukkaros Southwest Africa.Leeds University Research Institute of African Geology Annual Report, Vol. 8, PP. 21-24.Southwest Africa, NamibiaUltramafic Rocks, Melilite, Brukkaros
DS1960-0463
1964
Janse, A.J.A.Janse, A.J.A.Kimberlites and Related Rocks of the Nama Plateau of Southwest AfricaLeeds: Ph.d. Thesis, University Leeds, 266P.Southwest Africa, NamibiaKimberlite, Mineralogy, Petrology, Brukkaros
DS1960-1135
1969
Janse, A.J.A.Janse, A.J.A.Gross Brukkaros, a Probable Carbonatite Volcano in the Nama plateau of Southwest Africa.Geological Society of America (GSA) Bulletin., Vol. 80, No. 4, PP. 573-586.South Africa, Southwest Africa, NamibiaGeology, Kimberlite, Carbonatite
DS1970-0103
1970
Janse, A.J.A.Janse, A.J.A.Diamonds and Kimberlites, Their Occurrences and Distribution Throughout the World.Diamond Conference Held Oxford., No. 11, (abstract.) UNPAG.South Africa, Global, Southwest Africa, NamibiaDiamond Occurrences, Locations, History
DS1970-0104
1970
Janse, A.J.A.Janse, A.J.A.Diamonds and Kimberlites, Their Occurence and Distribution Throughout the World.Diamond Conference Oxford., ABSTRACT No. 11, (UNPUBL.).RussiaBlank
DS1970-0320
1971
Janse, A.J.A.Janse, A.J.A.Monticellite Bearing Porphyritic Peridotite from Gross Brukkaros, Southwest Africa.Geological Society of South Africa Transactions, Vol. 74, No. 2, PP. 45-55.Southwest Africa, NamibiaMineralogy, Petrology
DS1970-0726
1973
Janse, A.J.A.Janse, A.J.A.Kimberlites and Related Rocks from the Nama Plateau of South West Africa #11st International Kimberlite Conference, EXTENDED ABSTRACT VOLUME, PP. 177-180.Southwest Africa, NamibiaGeology
DS1975-0113
1975
Janse, A.J.A.Janse, A.J.A.Kimberlites and Related Rocks from the Nama Plateau of South West Africa #2Physics and Chemistry of the Earth., Vol. 9, PP. 81-94.Southwest Africa, NamibiaGeology, Carbonatite
DS1975-0540
1977
Janse, A.J.A.Janse, A.J.A.Harzburgite Nodules from a Lamprophyre Near Wawa, Ontario CanadaInternational Kimberlite Conference SECOND., EXTENDED ABSTRACT VOLUME.Canada, OntarioRelated Rocks
DS1975-0541
1977
Janse, A.J.A.Janse, A.J.A.Sloan 1 and 2 Diamondiferous Kimberlites, Larimer County, ColoradoInternal Report To American Selco, 8P.United States, Colorado, State Line, Rocky MountainsBlank
DS1975-0770
1978
Janse, A.J.A.Janse, A.J.A.Summary of Localities and Details of Finds to Accompany The map on Diamond and Kimberlite Occurrences in North America.Selco Inc., INTERNAL UNPUBL. REPORT.United States, Appalachia, Central StatesDiamond Occurrences, Listing, Catalogue
DS1975-1082
1979
Janse, A.J.A.Janse, A.J.A.First Reconnaissance in Northern Colorado and Southern Wyoming- Prairie Divide and Leucite Hills.Internal Report To American Selco, 7P.United States, Wyoming, Colorado, State Line, Rocky MountainsBlank
DS1982-0297
1982
Janse, A.J.A.Janse, A.J.A.Report Listing All Occurrences in the Great Lakes RegionB P Report For Bibliochrony, 10P. UNPUBL.United States, Wisconsin, Michigan, Illinois, Ohio, Iowa, IndianaWaukesha, Ozaukee, Pierce, Washington, Dodge, Racine, Dane, Green
DS1982-0443
1982
Janse, A.J.A.Mitchell, R.H., Janse, A.J.A.A Harzburgite Bearing Monchiquite from Wawa, OntarioCanadian Mineralogist., Vol. 20, PP. 211-216.Canada, OntarioMineralogy
DS1984-0376
1984
Janse, A.J.A.Janse, A.J.A.Kimberlites Where and WhenPreprint Draft of Paper Presented At The University of Weste, Feb. 16TH. 22P.GlobalHistory, Kimberlite, Genesis, Classification, Distribution, Pipes
DS1984-0377
1984
Janse, A.J.A.Janse, A.J.A.Kimberlites Where and When?Kimberlite Occurence And Origin A Basis For Conceptual Model, PP. 3-5. (abstract.)GlobalHistory, Theory, Distribution
DS1984-0378
1984
Janse, A.J.A.Janse, A.J.A.Kimberlites - Where and WhenUniversity of Western Australia GEOL. and University EXTENSION., No. 8, PP. 19-62.South Africa, United States, Brazil, Russia, India, Australia, AfricaTerminology, History, Geography, Chronology
DS1986-0396
1986
Janse, A.J.A.Janse, A.J.A., Downie, I.F., Reed, L.E., Sinclair, I.G.L.Alkaline diatremes in the Hudson Bay Lowlands, Canada,explorationmethods, petrology and geochemistryProceedings of the Fourth International Kimberlite Conference, Held Perth, Australia, No. 16, pp. 469-471OntarioDiamond exploration
DS1986-0397
1986
Janse, A.J.A.Janse, A.J.A., Downie, I.F., Reef, L.E., Sinclair, I.G.L.Alkaline diatremes in the Hudson Bay Lowlands: explorationmethods, mineralogy, petrology and geochemistryFick ( Proceedings Of The Fourth International Kimberlite Conference), Abstract 1pOntario, James Bay LowlandsAlkaline rocks
DS1987-0317
1987
Janse, A.J.A.Janse, A.J.A., Sheahan P.A.Bibliochrony of igenous rocks of Arkansaw with particular emphasis ondiamondsMantle metasomatism and alkaline magmatism, edited E. Mullen Morris and, No. 215, pp. 249-292GlobalBibliography
DS1988-0325
1988
Janse, A.J.A.Janse, A.J.A.The Argyle diamond mine (1988)Engineering and Mining Journal, Vol. 159, No. 6, July, pp. 26-27, 29-30AustraliaNews item, Argyle history
DS1989-0699
1989
Janse, A.J.A.Janse, A.J.A., Downie, I.F., Reed, L.E., Sinclair, I.G.L.Alkaline intrusions in the Hudson Bay Lowlands, Canada: explorationmethods, petrologyGeological Society of Australia Inc. Blackwell Scientific Publishing, Special, No. 14, Vol. 2, pp. 1192-1203OntarioExploration techniques, Geophysics, Petrology
DS1991-0785
1991
Janse, A.J.A.Janse, A.J.A.Diamond sources in Africa #1International Gemological Symposium, June 20-24, 1991 Los Angeles, Gems and Gemology, Vol. 27, Spring, Program p. 3AfricaDiamond production-sources
DS1991-0786
1991
Janse, A.J.A.Janse, A.J.A.The Argyle diamond mine -tectonic and geological setting, cost and time of discovery and developmentConference registration The Canadian Institute of Mining, Metallurgy and Petroleum (CIM) Xerox Tower Suite 1210, 3400 de Maissoneuve, Sept. 5-13, 1991 Fax 514 939-2714AustraliaArgyle, Economics
DS1991-0787
1991
Janse, A.J.A.Janse, A.J.A.Non-kimberlitic diamonds source rocksProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 199-201Ghana, Australia, Russia, KalimantanLamproite, Diamond source rocks -table of rock types
DS1992-0609
1992
Janse, A.J.A.Gregory, G.P., Janse, A.J.A.Diamond exploration in tropical terrainsin: Regolith exploration geochemistry in tropical and subtropical, Elsevier, ChapterV.1, pp. 419-437Australia, AfricaGeochemistry, Diamond exploration tropics
DS1992-0772
1992
Janse, A.J.A.Janse, A.J.A.Diamond sources in Africa #2Gemological Institute of America, Proceedings Volume ed. A. Keller, p. 55. (abstract)AfricaEconomics, Diamond production
DS1992-0773
1992
Janse, A.J.A.Janse, A.J.A.The Argyle diamond discovery, Kimberley Region, AustraliaThe Canadian Institute of Mining, Metallurgy and Petroleum (CIM) Exploration Mining Geology, Vol. 1, No. 4, October pp. 383-390AustraliaExploration methodology, costs, economics, Deposit -Argyle
DS1992-0774
1992
Janse, A.J.A.Janse, A.J.A.Archons and cratons - modern ideas on tectonic and structural control of economic kimberlitesPreprint from author, 17p. inc. 11p. text 5 figures, 1 tableGlobalCraton, Tectonics
DS1992-0775
1992
Janse, A.J.A.Janse, A.J.A.Archons and cratons, new ideas on tectonic control of economickimberlitesInternational Roundtable Conference on Diamond Exploration and Mining, held, pp.4-23GlobalCraton, Tectonics
DS1992-0776
1992
Janse, A.J.A.Janse, A.J.A.New ideas in subdividing cratonic areasRussian Geology and Geophysics, Vol. 33, No. 10, pp. 9-25Russia, Commonwealth of Independent States (CIS), GlobalCraton, Kimberlites
DS1993-0484
1993
Janse, A.J.A.Garanin, V.K., Kudryavtseva, G.P., Janse, A.J.A.Vertical and horizontal zoning of kimberlitesPreprint, 14p.Russia, Yakutia, Arkangelsk, South AfricaZonation, Kimberlites
DS1993-0737
1993
Janse, A.J.A.Janse, A.J.A.The aims and economic parameters of diamond explorationProspectors and Developers Diamond Workshop, held March 27th, Toronto, 10pGlobalEconomics, Diamonds
DS1993-0738
1993
Janse, A.J.A.Janse, A.J.A.Review of supposedly non-kimberlitic and non-lamproitic diamond hostrocks #1Preprint, 16p.GlobalOphiolite belts, metamorphic gneiss, lamprophyres, Peridotites, peridotite-dunite, basalt, eclogites
DS1994-0828
1994
Janse, A.J.A.Janse, A.J.A.Classification of microdiamonds and small diamonds. #1Diand Meeting November, Yellowknife, 1p. abstractGlobalClassification, Microdiamonds
DS1994-0829
1994
Janse, A.J.A.Janse, A.J.A.Is Clifford's Rule still valid? Affirmative examples from around theworld.Proceedings of Fifth International Kimberlite Conference, Vol. 2, pp. 215-235.GlobalDiamond exploration, Proterozoic craton, Clifford's Rule
DS1994-0830
1994
Janse, A.J.A.Janse, A.J.A.Review of supposedly non-kimberlitic and non-lamproitic diamond hostrocks #2Proceedings of Fifth International Kimberlite Conference, Vol. 2, pp. 144-159.GlobalDiamond host rocks, Review
DS1994-0831
1994
Janse, A.J.A.Janse, A.J.A.Kimberlites, lamproites and their world wide distribution and criteria for their evaluation of diamond potential.The Canadian Institute of Mining, Metallurgy and Petroleum (CIM) Short Course April 30, 45p.GlobalKimberlites, Lamproites
DS1994-0832
1994
Janse, A.J.A.Janse, A.J.A.Classification of microdiamonds and small diamonds. #2Northwest Territories 1994 Open House Abstracts, p. 43-44. abstractGlobalNews item, Microdiamond classification
DS1994-0833
1994
Janse, A.J.A.Janse, A.J.A.Kimberlite pipes -how big and how rich should they be?Prospectors and Developers Association of Canada (PDAC) Annual Meeting March 6-9th. held Toronto, Ontario, Final program abstract volume, p. 47, 48SaskatchewanEconomics, Value
DS1994-0834
1994
Janse, A.J.A.Janse, A.J.A., Danchin, R.V.Diamonds of western Australia: past present and futureGeological Society of Australia Abstract Volume, No. 37, pp. 194.AustraliaHistory
DS1994-0835
1994
Janse, A.J.A.Janse, A.J.A., Danchin, R.V.Diamonds of Western Australia - past, present and futureGeological Society of Australia Abstracts, No. 37, p. 194.Australia, Western AustraliaBrief overview
DS1994-1753
1994
Janse, A.J.A.Taylor, W.R., Zhang, A., Janse, A.J.A.Leucitites and other potassic igneous rocks of the Yangtze Craton, southChin a and their diamond bearing potential.Geological Association of Canada (GAC) Abstract Volume, Vol. 19, p. PosterChinaAlkaline rocks, Yangtze Craton
DS1995-0871
1995
Janse, A.J.A.Janse, A.J.A., Novak, N.A., MacFadyen. D.A.Discovery of a new type of highly Diamondiferous kimberlitic rocks in The james Bay Lowlands, Northern OntarioProceedings of the Sixth International Kimberlite Conference Abstracts, pp. 260-262.OntarioKimberlite, Deposit -Kyle Lake area
DS1995-0872
1995
Janse, A.J.A.Janse, A.J.A., Sheahan, P.A.Catalogue of world wide diamond and kimberlite occurrences; a selective and annotative approach.Journal of Geochemical Exploration, Vol. 52, pp. 73-112.GlobalDiamond bibliography, Kimberlite bibliography
DS1997-0552
1997
Janse, A.J.A.Janse, A.J.A.Modern methods of evaluation of diamond deposits and present explorationactivity.Papupunen: 4th. Biennial SGA Meeting, pp. 7-8. AbstractGlobalDiamond exploration, Methodology
DS1998-0685
1998
Janse, A.J.A.Janse, A.J.A.Diamonds in AfricaAustralia Ins. Geoscient. Bulletin., No. 25, pp. 51-59.AfricaHistory, production, statistics, Craton - locations
DS1998-0686
1998
Janse, A.J.A.Janse, A.J.A.Archons, protons and tectons: an update7th International Kimberlite Conference Abstract, pp. 377-9Australia, China, India, Africa, Canada, RussiaTectonics, Craton - framework
DS1998-1461
1998
Janse, A.J.A.Thomas, R.D., Novak, N.A., Janse, A.J.A.Diamonds in ultrabasic rock near Wawa Ontario, Canada7th International Kimberlite Conference Abstract, pp. 908-10.OntarioPetrology, diamond content, xenoliths, dikes, Deposit - Sandor, Nicholson
DS2001-0208
2001
Janse, A.J.A.Coopersmith, H.G., Janse, A.J.A.Diamond exploration in the United States. Brief overview of areas of interest.Colorado Mining Association., Sept. 1p. abstractColorado, WyomingLamproite, kimberlite, exploration
DS2001-0209
2001
Janse, A.J.A.Coopersmith, H.G., Janse, A.J.A.Diamond exploration in the United StatesNw Mining Association Meet., Dec. 7, 1p. abstr.United StatesNews item
DS2002-0765
2002
Janse, A.J.A.Janse, A.J.A.Lowland ranked high in diamond prospectivity: history of its diamond explorationProspectors and Developers Association of Canada (PDAC) 2002, 1p. abstractOntario, James Bay LowlandsHistory - brief
DS2003-0647
2003
Janse, A.J.A.Janse, A.J.A., Sheahan, P.A.Getting their feet wet, Selco's efforts to explore for diamonds in the James BayGeological Association of Canada Annual Meeting, Abstract onlyOntario, Northwest TerritoriesHistory - Selco
DS200412-0904
2004
Janse, A.J.A.Janse, A.J.A.Diamond presentations at the Australian Diamond Conference held Dec. 1-3, 2003 (Perth).Gems & Gemology, Vol. 40, 1, Spring, pp.81-82.AustraliaConference overview - junior company exploration activi
DS200412-0905
2003
Janse, A.J.A.Janse, A.J.A., Sheahan, P.A.Getting their feet wet, Selco's efforts to explore for diamonds in the James Bay Lowlands.Geological Association of Canada Annual Meeting, Abstract onlyCanada, Ontario, Northwest TerritoriesHistory - Selco
DS200612-0496
2005
Janse, A.J.A.Gregoire, M., Rabonowicz, M., Janse, A.J.A.Mantle mush compaction: a key to understand the mechanisms of concentration of kimberlite melts and initiation of swarms of kimberlite dykes.Journal of Petrology, Vol. 47, 3, March, pp. 631-646,Africa, South Africa, Lesotho, BotswanaConvection, Kimberley, Rietfontein, Central Cape,Gibeon
DS200712-0485
2006
Janse, A.J.A.Janse, A.J.A.Major diamond mines of the world: tectonic location, production and value.Gems & Gemology, 4th International Symposium abstracts, Fall 2006, p.148-9. abstract onlyGlobalDiamond production
DS200712-0486
2006
Janse, A.J.A.Janse, A.J.A.Global rough diamond production from 1870-2005.Gems & Gemology, 4th International Symposium abstracts, Fall 2006, p.136. abstract onlyGlobalDiamond production figures
DS200912-0617
2009
Janse, A.J.A.Read, G.H., Janse, A.J.A.Diamonds: exploration, mines and marketing.Lithos, in press available, 8p.GlobalProduction, economics
DS201012-0695
2010
Janse, A.J.A.Shigley, J.E., Laur, B.M., Janse, A.J.A., Elen, S., Dirlam, D.M.2010 gem localities of the 2000's.Gems & Gemology, Vol. 46, 3, pp. 188-216.GlobalDiamond included in profile
DS201212-0337
2012
Janse, A.J.A.Janse, A.J.A.Diamond production and discoveries over the last fifteen years.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractGlobalHistory - deposits
DS201512-1968
2015
Janse, A.J.A.Shor, R., Weldon, R., Janse, A.J.A., Breeding, C.M., Shirey, S.B.Diamonds from the Letseng mine. Explores the history, geology, and current production of this unique source of large diamonds. Letseng La TeraeGems & Gemology, Vol. 51, 3, pp. 280-299.Africa, LesothoDeposit - Letseng
DS201809-2045
2018
Janse, A.J.A. BramJanse, A.J.A. BramEssential books on diamond. List by author and overview of each technical book biased to diamond.The Australian Gemmologist, Vol. 26, 9-10, pp. 217-225.Globalgemstones - diamond

Abstract: I have been asked several times in the past to provide a list of books on diamond that are essential to "the interested layperson" and the gemmologist who is just starting out – either a student or a lover of gems. These books I would class as essential reading for persons wanting to know more about diamonds, including their physical properties, crystal forms, beauty in cut and polished shapes, exploration, mining and trade. I have presented here a list of books based on three levels of understanding – initial, intermediate and advanced. Many of the books quoted are out of print, but a diligent search on Amazon, Book Depository, Booktopia, Fish Pond Australia or Abe Books will find these books for sale, either new or second hand. For the first, initial level there are four essential books. After reading and digesting these, one could be seen as a knowledgeable person, not an expert, as this takes more time and study. The books do not require scientific education at university level, instead a general knowledge of science, a good mind and common sense are all that is needed to enjoy these books. The first book listed was published to accompany the wonderful exhibition of the ‘World of Diamonds’ organised by the American Museum of Natural History in New York in 1998. The exhibition travelled to a few other venues in the next two years, but very high insurance costs restricted this effort. Not to be outdone, the Muséum National d’Histoire Naturelle in Paris organised a similar wonderful exhibition in 2001, based more on diamond jewellery than on diamonds themselves. This exhibition only travelled to Rome, again high insurance prevented further travel. The second book, published in a French and an English edition, was issued to accompany and describe the French exhibition. [The exhibition in the Natural History Museum in London in 2005 unfortunately was closed after only a few weeks in 2005 because of the threat of a robbery. This raised the cost of insurance to unacceptable levels for entrance fees. The exhibition was described in a slim booklet by Dixon which I have listed for completeness, as well as the volume on the diamond jubilee exhibition in Buckingham Palace in 2012, but it is not essential reading]. The third book is dedicated to diamonds as jewels. It portrays about one hundred famous and notable cut and polished diamonds, and has gone to its fifth edition by now. The fourth book is a primer on diamond geology and mineralogy written for the general reader interested in diamonds.
DS1995-0873
1995
Janse, B.Janse, B.A history of diamond sources in Africa: Part 1Gems and Gemology, Vol. 31, Winter pp. 228-255.Africa, South Africa, Botswana, Namibia, Zaire, AngolaHistory, Diamond exploration
DS1995-0874
1995
Janse, B.Janse, B.Diamond potential of CanadaUniversity of West. Australian Key Centre, held Feb. 15, 16th., 32p.CanadaDiamond exploration
DS1995-0875
1995
Janse, B.Janse, B.Diamond and gold in India... recent developments and prospectingactivities.Prospectors and Developers Association of Canada (PDAC) Annual Meeting, p. 54. abstractIndiaReview
DS1996-0680
1996
Janse, B.Janse, B.A history of diamond sources in Africa: Part IIGems and Gemology, Vol. 32, Spring pp. 2-30.AfricaHistory, Diamond genesis, operations, notable gems
DS2002-0766
2002
Janse, B.Janse, B.DiamondsMining Annual Review, 12p.GlobalReview - 2001, History, exploration activities, production
DS200612-0637
2006
Janse, B.Janse, B.Diamond exploration. The worldwide search continues unabated.London Mining Journal, Augist 18, pp. 19-21,23,26.GlobalOverview - exploration 2005
DS200612-0638
2006
Janse, B.Janse, B.African diamonds: the search widens.World Mining Stocks, March pp. 38-39,AfricaNews item - exploration activity
DS200612-0639
2006
Janse, B.Janse, B.African diamonds - the search widens.London Mining Journal, Jan. 27, pp. 20-21,23-25.AfricaNews item - overview
DS200612-0640
2005
Janse, B.Janse, B.The search for diamonds... half of global diamond exploration expenditure is spent in Canada - and it is producing results.World Mining Stocks, Nov. pp. 46,47.CanadaNews item - overview
DS200912-0335
2009
Janse, B.Janse, B.Diamonds search for new best friend. Overview of 2008 by country/region.London Mining Journal, Sept. 11, pp. 18-25.GlobalReview - diamond activity, exploration, production
DS201112-0478
2011
Janse, B.Janse, B.3,000 years of production.London Mining Journal Diamonds supplement, June p. 5.GlobalNews item - history - production
DS201705-0836
2017
Janse, B.Janse, B.Geology of Diamond.lithographie.org, No. 19, pp. 10-23.TechnologyBook - geology
DS1992-0777
1992
Janse. A.J.A.Janse. A.J.A.Diamond prospectivity of the Hudson Bay LowlandReport to C.P.M., handout by K.W.G. at meeting held October 19th., 13p. l table, Figures 1-4 onlyOntarioCraton, Overview
DS1995-1733
1995
Jansen, H.F.J.Sherman, D.M., Jansen, H.F.J.First principle prediction of the high pressure phase transition and electronic structure of FeO:mantle/coreGeophysical Research. Letters, Vol. 22, No. 8, Apr. 15, pp. 1001-4.MantleGeochemistry
DS200612-1539
2005
Jansen, J.Witherley, K., Jansen, J.Condor Consulting & Teck Cominco - The Tli Kwi Cho kimberlite - a geophysical case study. ( DO-27)32ndYellowknife Geoscience Forum, p. 83 abstractCanada, Northwest TerritoriesUpdate - Condor
DS1989-1547
1989
Jansen, S.L.Veizer, J., Laznicka, P., Jansen, S.L.Mineralization through geologic time: recycling perspectiveAmerican Journal of Science, Vol. 289, April pp. 484-524. Database # 17843GlobalMetallogeny, Review -Recycling
DS1992-1602
1992
Jansen, S.L.Veizer, J., Bell, K., Jansen, S.L.Temporal distribution of carbonatitesGeology, Vol. 20, No. 12, December pp. 1147-1149.MantleCarbonatite, Distribution
DS1992-0778
1992
Jansen, W.T.Jansen, W.T.Mineralogical and geological analysis using hyper spectral dataGeobyte, Vol. 7, No. 5, pp. 50-53GlobalComputer, Analytical spectroscopy
DS200812-0516
2007
Janson, G.Janson, G., Muehlenbachs, K., Stachel, T., Eichenberg, D.Cyclic growth conditions for Diavik diamonds? Insights from carbon isotopes.35th. Yellowknife Geoscience Forum, Abstracts only p. 28.Canada, Northwest TerritoriesDiamond morphology - Diavik
DS200812-0517
2008
Janson, G.F.Janson, G.F., Muehlenbachs, K., Stachel, T., Eichenber, D.Microscale variations in D13 C evidence for growth of coated Diavik diamonds from kimberlite derived fluid.Northwest Territories Geoscience Office, p. 38. abstractCanada, Northwest TerritoriesDeposit - Diavik
DS201112-0976
2011
Janssen, A.Smit, M.A., Scherer, E.E., John, T., Janssen, A.Creep of garnet in eclogite: mechanisms and implications.Earth and Planetary Science Letters, Vol. 311, 3-4, pp. 411-419.MantlePetrology
DS1995-0876
1995
Janssen, M.E.Janssen, M.E., Stephenson, R.A., Cloetingh, S.Temporal and spatial correlations between changes in plate motions and the evolution of rifted basins AfricaGeological Society of America (GSA) Bulletin, Vol. 107, No. 11, Nov. pp. 1317-1332AfricaBasins, Geodynamics, tectonics
DS200712-0106
2007
JanssensBrenker, F.E., Vollmer, C., Vincze, L., Vekemans, B., Szymanski, Janssens, Szaloki, Nasdala, Joswig, KaminskyCarbonates from the lower part of transition zone or even the lower mantle.Earth and Planetary Science Letters, Vol. 260, 1-2, pp. 1-9.MantleCarbonates
DS200712-0107
2007
JanssensBrenker, F.E., Vollmer, C., Vincze, L., Vekemans, B., Szymanski, Janssens, Szaloki, Nasdala, Joswig, KaminskyCarbonates from the lower part of transition zone or even the lower mantle.Earth and Planetary Science Letters, Vol. 260, 1-2, pp. 1-9.MantleCarbonates
DS200712-0108
2007
JanssensBrenker, F.E., Vollmer, Vincze, Vekemans, Szymanski, Janssens, Szaloki, Nasdala, Joswig, KaminskyCarbonates from the lower part of transition zone or even the lower mantle.Earth and Planetary Science Letters, Vol. 260, 1-2, pp. 1-9.MantleCarbonates
DS200612-0171
2006
Janssens, K.Brenker, F.E., Vollmer, C., Vincze, L., Vekemans, B., Szymanski, A., Janssens, K., Szaloki, I., Nasdala, L., Joswig, W., Kaminsky, F.CO2 recycling to the deep convecting mantle.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 1, abstract only.MantleConvection
DS201412-0957
2014
JantienWaal, A., Orij, Rosman, R., Jantien, Zevenbergen, M.Applicabaility of the high performance organization framework in the diamond industry value chain.Journal of Strategy and Management , Vol. 7, 1, pp. 30-48.GlobalDiamond financial - economics
DS1992-0779
1992
Janulaitis, V.Janulaitis, V., Rawlinson, R.G.Supporting a remote mine in AfricaMinerals Industry International, July pp. 12-15GuineaMining, Aredor mine
DS201212-0338
2012
Januszcak, M.H.Januszcak, M.H., Seller, S., Kurzlaukis, C., Murphy, J., Delgaty, S., Tappe, K., Ali, J.Zhu, Ellemers, P.A multidisciplinary approach to the Attawapiskat kimberlite field, Canada Canada: accelerating the discovery to production pipeline.10th. International Kimberlite Conference Feb. 6-11, Bangalore India, AbstractCanada, Ontario, AttawapiskatDeposit - Victor
DS200412-0530
2004
Januszczak, N.Eyles, N., Januszczak, N.Zipper rift a tectonic model for Neoproterozoic glaciations during the breakup of Rodinia after 750 Ma.Earth Science Reviews, Vol. 65, 1-2, pp. 1-73GondwanaGeomorphology, tectonics, Snowball Earth
DS200512-0275
2004
Januszczak, N.Eyles, N., Januszczak, N.Interpreting the Neoproterozoic glacial record: the importance of tectonics.American Geophysical Union, Geophysical Monograph, No. 146, pp. 125-144.Geomorphology - tectonics
DS201312-0437
2013
Januszczak, N.Januszczak, N.A multidisciplinary approach to the Attawapiskat kimberlite field: accelerating the discovery to production pipeline.Toronto Geological Discussion Group, 1p. abstractCanada, Ontario, AttawapiskatDeposit - Victor/ area
DS201312-0438
2013
Januszczak, N.Januszczak, N., Seller, M.H., Kurszlaukis, S.A multidisciplinary approach to the Attawapiskat kimberlite field, Canada: accelerating discovery-to-production pipeline.Proceedings of the 10th. International Kimberlite Conference, Vol. 2, Special Issue of the Journal of the Geological Society of India,, Vol. 2, pp. 157-171.Canada, Ontario, AttawapiskatDeposit - Victor
DS201412-0424
2013
Januszczak, N.Januszczak, N., Seller, M.H., Kurzlaukis, S., Murphy, C., Delgaty, J., Tappe, S., Ali, K., Zhu, J., Ellemers, P.A multidisciplinary approach to the Attwapiskat kimberlite field, Canada: accelerating the discovery-to-production pipeline.Proceedings of the 10th. International Kimberlite Conference, Vol. 2, pp. 157-172.Canada, Ontario, AttawapiskatDeposit - Victor area
DS201912-2794
2019
Januszczak, N.Kjarsgaard, B.A., Januszczak, N., Stiefenhofer, J.Diamond exploration and resource evaluation of kimberlites.Elements, Vol. 15, 6, pp.Mantleresource evaluation

Abstract: Kimberlites are the main source of natural gem-quality diamonds. The intrepid diamond explorer faces three major problems. First, finding a small, usually less than 300 m diameter, kimberlite, which is often highly weathered. Second, evaluating the quantity of diamonds within a kimberlite that often consists of multiple phases of intrusive and extrusive kimberlite, each with potentially different diamond grades. Third, evaluating the rough diamonds, the value of which is dependent on carat-weight, shape, colour, and clarity. Modern advances in mantle petrology, geophysics, geochemistry, geomorphology, and geostatistics now complement historical exploration knowledge and aid in selecting prospective target areas, resource estimation, and evaluating kimberlite-hosted diamond deposits.
DS202205-0672
2022
Januszczak, N.Afonso, J., Ben-Mansour, W., O'Reilly, S.Y., Griffin, W.L., Salajeghegh, F., Foley, S., Begg, G., Selway, K., Macdonald, A., Januszczak, N., Fomin, I., Nyblade, A.A., Yang, Y.Thermochemical structure and evolution of cratonic lithosphere in central and southern Africa.Nature Geoscience, Apr. 26, 329p. FreeAfrica, South AfricaCraton

Abstract: The thermochemical structure of the subcontinental mantle holds information on its origin and evolution that can inform energy and mineral exploration strategies, natural hazard mitigation and evolutionary models of Earth. However, imaging the fine-scale thermochemical structure of continental lithosphere remains a major challenge. Here we combine multiple land and satellite datasets via thermodynamically constrained inversions to obtain a high-resolution thermochemical model of central and southern Africa. Results reveal diverse structures and compositions for cratons, indicating distinct evolutions and responses to geodynamic processes. While much of the Kaapvaal lithosphere retained its cratonic features, the western Angolan-Kasai Shield and the Rehoboth Block have lost their cratonic keels. The lithosphere of the Congo Craton has been affected by metasomatism, increasing its density and inducing its conspicuous low-topography, geoid and magnetic anomalies. Our results reconcile mantle structure with the causes and location of volcanism within and around the Tanzanian Craton, whereas the absence of volcanism towards the north is due to local asthenospheric downwellings, not to a previously proposed lithospheric root connecting with the Congo Craton. Our study offers improved integration of mantle structure, magmatism and the evolution and destruction of cratonic lithosphere, and lays the groundwork for future lithospheric evolutionary models and exploration frameworks for Earth and other terrestrial planets.
DS201812-2876
2018
Janzen, R.Ross, M., Kelley, S.E., Janzen, R., Stirling, R.A., Normandeau, P.X., Elliott, B.Orphan and elusive glacial dispersal trains from kimberlites in the Lac de Gras area.2018 Yellowknife Geoscience Forum , p. 65-66. abstractCanada, Northwest Territoriesgeochemistry

Abstract: Numerous glacial dispersal trains, spatially and compositionally associated to kimberlites, have been characterized and mapped in the Lac de Gras region, Northwest Territories (NT). However, a small number of these trains have yet to be associated with a source. Additionally, a number of known sub-cropping kimberlites do not have well-defined, spatially associated, trains of indicator minerals. These issues suggest that local factors may be important in controlling the occurrence, shape, and strength of a dispersal pattern and its spatial association with a kimberlite. Identifying these factors and understanding their effect on the dispersion of indicator minerals could provide a road map for finding additional diamondiferous kimberlites in the NT and elsewhere. Here we examine contrasting dispersal trains from south and southwest of Lac de Gras, as well as situations where the source of known dispersal trains (e.g., Coppermine Train) continue to elude exploration geologists. Using both surface and subsurface datasets, we find that the bedrock geology and topography of the source area, as well as those of the dispersal area, are potential key controls on the type and shape of dispersal patterns. Even across discontinuous drift and subdued shield relief we find that bedrock topography and lithology modulated the effect of glacial dynamics on till production and provenance. These 'bedrock factors' have interacted in various ways during Quaternary glaciations, in combinations unique to each case, to generate complex dispersal patterns in three dimensions. Accounting for these factors, using both surface and subsurface data, could enhance the success of drift exploration programs and improve their outcome in the glaciated shield terrains of northern Canada.
DS201712-2724
2017
Janzen, R.J.D.Ross, M., Kelley, S.E., Janzen, R.J.D., Stirling, R.A., Normandeau, P.X., Elliott, B.Tracing the breadcrumbs back tp their source: exploring geological factors controlling production of atypical glacial dispersal patterns of indicator minerals45th. Annual Yellowknife Geoscience Forum, p. 67 abstractCanada, Northwest Territoriesgeochemistry - indicator minerals

Abstract: Tracing surficial dispersal patterns of indicator minerals within glacial sediments in the main up-ice direction has greatly contributed to numerous mineral discoveries of economic value in the Northwest Territories. However, many cases have also reported perplexing scenarios of dispersal trains seemingly lacking a source, or known sources without a spatially associated dispersal train at the surface. These ‘special’ cases often hinder exploration efforts, and tend to remain poorly understood; yet these cases are becoming increasingly important to decipher as exploration moves into more complex terrains. We present an overview of our research done in the Lac de Gras area over the past few years in collaboration with the Northwest Territories Geological Survey and their partners investigating the effect of multiple ice flows, variable bedrock topography and drift thickness, and the complexities of glacial sedimentary environments on 2D and 3D mechanical (detrital) dispersion. Our research draws from surface and subsurface datasets from various sources at both the regional and local scales. We show that despite the occurrence of relatively long, continuous, surficial patterns extending in the direction of the latest-strongest ice flow event in the region, a subtle record of the time-transgressive glacial history is also frequently preserved. These records yield information about the net effect on sediment dispersion of multiple ice flow phases, bedrock geology, basal topography, and glacial depositional processes. Our findings suggest these geological factors played a key role in producing some of the most irregular and enigmatic dispersal patterns in the region. They also offer insights into how to best characterize and explain the signal (or lack thereof) from elusive buried sources of potential economic interest.
DS1993-0372
1993
JaoulDoukhan, N., Doukhan, J-C., Ingrin, J., Jaoul, RatteronEarly partial melting in pyroxenesAmerican Mineralogist, Vol. 78, pp. 1246-56.MantleMelting - xenoliths
DS1999-0333
1999
Jaoul, O.Jaoul, O., Sautter, V.A new approach to geospeedometry based on the 'compensation law'Physical Earth and Planetary Interiors, Vol. 110, pp. 95-114.MantleCooling rate, Lasaga's model
DS2001-0509
2001
Jaoul, O.Ingrin, J., Pacaud, L., Jaoul, O.Anisotropy of oxygen diffusion in diopsideEarth and Planetary Science Letters, Vol. 192, No. 3, pp. 347-61.GlobalMineral chemistry - diopside
DS2003-0092
2003
Jaoul, O.Bejina, F., Jaoul, O., Liebermann, R.C.Diffusion in minerals at high pressure: a reviewPhysics of the Earth and Planetary Interiors, Vol. 139, 1-2, Sept. 30, pp. 3-20.GlobalPetrology, experimental, UHP
DS200412-0126
2003
Jaoul, O.Bejina, F., Jaoul, O., Liebermann, R.C.Diffusion in minerals at high pressure: a review.Physics of the Earth and Planetary Interiors, Vol. 139, 1-2, Sept. 30, pp. 3-20.TechnologyPetrology, experimental, UHP
DS1993-0739
1993
Japan Society of GeoinformaticsJapan Society of GeoinformaticsRecent advances in geomathematics and geoinformaticsJapan Society of Geoinformatics, 246p. approx. $ 30.00JapanBook -ad, Geomathematics
DS200612-0150
2006
Japsen, P.Bonow, J.M., Lidmar Bergstrom, K., Japsen, P.Paleosurfaces in central West Greenland as reference for identification of tectonic movements and estimation of erosion.Global and Planetary Change, Vol. 50, 3-4, pp. 161-183.Europe, GreenlandTectonics
DS1990-0934
1990
Jaque, F.Lifante, G., Jaque, F., Hoyos, M.A., Leguey, S.Testing of colourless natural diamonds by room temperature opticalabsorptionJournal of Gemology, Vol. 22, No. 3, July, pp. 142-146GlobalNatural diamonds, Absorption
DS1859-0071
1841
Jaquemont, V.Jaquemont, V.Voyage dans L'indenpendant Pendant les Annees 1828 a 1832Unknown, IndiaTravelogue
DS1998-0687
1998
Jaques, A L.Jaques, A L.Kimberlite and lamproite diamond pipesAustralian Journal of Geology Geophys., Vol. 17, No. 4, pp. 153-168.AustraliaMineral deposit - model
DS1994-1665
1994
Jaques, A.Solomon, M., Groves, D.I., Jaques, A.The geology and origin of Australia's mineral depositsOxford Press, 960p. approx. $ 410.00AustraliaBook -table of contents, Deposits
DS200512-0809
2005
Jaques, A.I.O'Neill, C.J., Moresi, L., Jaques, A.I.Geodynamic controls on diamond deposits: implications for Australian occurrences.Tectonophysics, Vol. 404, 3-4, Aug. 1, pp. 217-236.AustraliaGeodynamics - diamond deposits
DS200912-0459
2009
Jaques, A.I.Luguet, A., Jaques, A.I., Pearson, D.G., Smith, C.B., Bulanova, G.P., Roffey, S.L., Rayner, M.J., Lorand, J.P.An integrated petrological, geochemical and Re-Os isotope study of peridotite xenoliths from the Argyle lamproite, western Australia and implications forLithos, In press available, 64p.AustraliaGeochronology - Cratonic diamond occurrences
DS1998-1449
1998
Jaques, A.J.Taylor, W.R., Jaques, A.J.Crystallization history of the Argyle and Ellendale olivine lamproites:constraints from spinel - olivine.7th International Kimberlite Conference Abstract, pp. 888-90.AustraliaGeothermometry, oxygen barometry, Deposit - Argyle, Ellendale
DS1982-0298
1982
Jaques, A.L.Jaques, A.L., Gregory, G.P., Lewis, J.D., Ferguson, J.The Ultrapotassic Rocks of the West Kimberley Region, Western Australia, and a New Class of Diamondiferous Kimberlite.Proceedings of Third International Kimberlite Conference, TERRA COGNITA, ABSTRACT VOLUME., Vol. 2, No. 3, PP. 251-252, (abstract.).AustraliaKimberlite, Leucite, Lamproite, Ellendale, Calwynyardah, Noonkanb
DS1983-0329
1983
Jaques, A.L.Jaques, A.L., Ferguson, J.Diamond Province Studies: Contrasts in the South Australian and West Kimberley Fields.B.m.r. Journal of Geology Geophys., Vol. 8, No. 2, JUNE PP. 172-173. (ABSTRACT)Australia, Western Australia, South Australia, Kimberley AreaGeochronology, Petrography, Related Rocks, Lamproite, Kimberlite
DS1983-0439
1983
Jaques, A.L.Mcculloch, M.T., Jaques, A.L., Nelson, D.R., Lewis, J.D.Neodymium and Strontium Isotopes in Kimberlites and Lamproites from western Australia and Enriched Mantle Origin.Nature., Vol. 302, No. 5907, PP. 400-403.AustraliaIsotope, Lamproite, Kimberlite, Petrology
DS1984-0275
1984
Jaques, A.L.Ferguson, J., Jaques, A.L.Structural Controls of Kimberlite #1Kimberlite Occurrence And Origin A Basis For Conceptual Mode, P. 26. (abstract.).AustraliaGeophysics, Structure, Genesis, Kimberlite
DS1984-0276
1984
Jaques, A.L.Ferguson, J., Jaques, A.L.Structural Controls of Kimberlite #2University of Western Australia - Special Publication, No. 8, PP. 291-292. (abstract.).AustraliaStructure
DS1984-0379
1984
Jaques, A.L.Jaques, A.L., Ferguson, J., Smith, C.B.Kimberlites in AustraliaUniversity of Western Australia - Special Publication, No. 8, PP. 227-274.Australia, Western Australia, South Australia, East AustraliaDistribution, Occurrences
DS1984-0380
1984
Jaques, A.L.Jaques, A.L., Lewis, J.D., Smith, C.B., Gregory, G.P., Ferguson.The Diamond Bearing Ultrapotassic Lamproitic Rocks of the West Kimberley Region Western Australia.Proceedings of Third International Kimberlite Conference, Vol. 1, PP. 225-254.AustraliaLamproite, Geochronology, Ellendale, Calwynyardah, Noonkanbah
DS1984-0381
1984
Jaques, A.L.Jaques, A.L., Perkin, D.J.A Mica, Pyroxene, Ilmenite Megacryst Bearing Lamprophyre From Mt. Woolooma, Northeastern New South Wales.B.m.r. Journal of Aust., Vol. 9, No. 1, MARCH PP. 33-40.Australia, New South WalesBlank
DS1984-0382
1984
Jaques, A.L.Jaques, A.L., Webb, A.W., Fanning, C.M., Black, C.P., Pidgeon, R.The Age of the Diamond Bearing Pipes and Associated LeuciteB.m.r. Journal of Aust. Geol. Geophys., Vol. 9, PP.Australia, Western AustraliaGeochronology, Related Rocks
DS1984-0414
1984
Jaques, A.L.Knutson, J., O'reilly, S.Y., Duggan, M.B., Jaques, A.L.The Nature of the Lower Crust and Upper Mantle Beneath Eastern Australia As Inferred from Xenolith Studies.Geological Society of Australia., No. 12, ABSTRACT VOLUME PP. 310-311.Australia, Eastern AustraliaXenoliths, Petrography
DS1984-0547
1984
Jaques, A.L.Nelson, D.R., Mcculloch, M.T., Jaques, A.L.neodymium, Strontium isotope ratios in ultrapotassic rocks from southeast Australia and their implications from the subcontinental lithosphereIn: Geoscience in the development of Natural Resources Abstract Volume, Vol. 12, pp. 401-402AustraliaBlank
DS1984-0548
1984
Jaques, A.L.Nelson, D.R., Mcculloch, M.T., Jaques, A.L.Nd-sr Isotope Ratios in Ultrapotassic Rocks from Southeast Australia and Their Implications from the Subcontinental Lithosphere.Geological Society of Australia., No. 12, ABSTRACT VOLUME, PP. 401-402.Australia, Southeastern AustraliaGeochronology, Leucitite
DS1985-0306
1985
Jaques, A.L.Jaques, A.L., Creaser, R.A., Ferguson, J., Smith, C.B.A Review of the Alkaline Rocks of AustraliaTransactions Geological Society of South Africa, Vol. 88, pt. 2, May-August pp. 311-334. plus fiche of aAustraliaAlkaline Rocks, Carbonatite
DS1985-0307
1985
Jaques, A.L.Jaques, A.L., Foley, S.F.The origin of Aluminum rich spinel inclusions in leucite from The leucite lamproites of western AustraliaAmerican Mineralogist, Vol. 70, pp. 1143-1150Australia, Western AustraliaLamproite
DS1986-0023
1986
Jaques, A.L.Andrews, R.L., Richards, M.N., Jaques, A.L., Knutson, J., TownendThe Cummins Range carbonatite, Western AustraliaProceedings of the Fourth International Kimberlite Conference, Held Perth, Australia, No. 16, pp. 12-14AustraliaCarbonatite
DS1986-0244
1986
Jaques, A.L.Fielding, D.C., Jaques, A.L.Geology, petrology and geochemistry of the Bow Hill lamprophyredykes, Western AustraliaProceedings of the Fourth International Kimberlite Conference, Held Perth, Australia, No. 16, pp. 24-26AustraliaBlank
DS1986-0319
1986
Jaques, A.L.Gupta, A.K., Yagi, K., Lovering, J., Jaques, A.L.Geochemical and microprobe studies of diamond bearing ultramafic rocks from central and south IndiaProceedings of the Fourth International Kimberlite Conference, Held Perth, Australia, No. 16, pp. 27-29IndiaGeochemistry, Mineral chemistry
DS1986-0398
1986
Jaques, A.L.Jaques, A.L.F-rich micas in the West Kimberley lamproites; contrasts withKimberlites and other micaceous alkaline ultramafic intrusionsProceedings of the Fourth International Kimberlite Conference, Held Perth, Australia, No. 16, pp. 45-47AustraliaLamproite
DS1986-0399
1986
Jaques, A.L.Jaques, A.L., Boxer, G., Lucas, H., Haggerty, S.E.Mineralogy and petrology of the Argyle lamproite pipe, WesternProceedings of the Fourth International Kimberlite Conference, Held Perth, Australia, No. 16, pp. 48-50AustraliaPetrology, Lamproite
DS1986-0400
1986
Jaques, A.L.Jaques, A.L., Sheraton, J.W., Hall, A.E., Smith, C.B. , Sun, S.S.Composition of crystalline inclusions and C-isotopic composition of Argyle and Ellendale diamonds #2Geological Society of Australia Abstract Series, No. 16, pp. 426-428. (Abstract)AustraliaMineralogy
DS1986-0401
1986
Jaques, A.L.Jaques, A.L., Sheraton, J.W., Hall, A.E., Smith, C.B., Sun, S-S.Composition of crystalline inclusions and C-isotopic composition of Argyle and Ellendale diamonds #1Proceedings of the Fourth International Kimberlite Conference, Held, No. 16, pp. 426-428AustraliaDiamond inclusions
DS1986-0402
1986
Jaques, A.L.Jaques, A.L., Sun, S.S., Chappell, B.W.Geochemistry of the Argyle lamproite pipeProceedings of the Fourth International Kimberlite Conference, Held Perth, Australia, No. 16, pp. 51-53AustraliaGeochemistry, Lamproite
DS1986-0431
1986
Jaques, A.L.Kerr, I.D., Jaques, A.L., Lucas, H., Sun, S.S., Chappell, B.W.Diamond bearing alkaline intrusions from Wandagee CarnarvonBasin, WesternAustraliaProceedings of the Fourth International Kimberlite Conference, Held Perth, Australia, No. 16, pp. 54-56AustraliaPetrology, Picrites
DS1986-0619
1986
Jaques, A.L.O'Neill, H.St. C., Jaques, A.L., Smith, C.B., Moon, J.Diamond bearing peridotite xenoliths from the Argyle (AK1) pipeProceedings of the Fourth International Kimberlite Conference, Held Perth, Australia, No. 16, pp. 300-302AustraliaBlank
DS1986-0789
1986
Jaques, A.L.Sun, S.S., Jaques, A.L., McCulloch, M.T.Isotopic evolution of the Kimberley block, western AustraliaProceedings of the Fourth International Kimberlite Conference, Held Perth, Australia, No. 16, pp. 346-348AustraliaBlank
DS1987-0318
1987
Jaques, A.L.Jaques, A.L.Diamond bearing lamproites from Western Australia: multiple tapping of old enriched lithosphere beneath Proterozoic mobile beltsTerra Cognita, Conference abstracts Oceanic and Continental Lithosphere:, Vol. 7, No. 4, Autumn, abstract only p. 616AustraliaBlank
DS1988-0270
1988
Jaques, A.L.Griffin, W.L., Jaques, A.L., Sie, S.H., Ryan, C.G., Cousens, D.R.Conditions of diamond growth: a proton microprobe study of inclusions inWest Australian diamondsContributions to Mineralogy and Petrology, Vol. 99, No. 2, pp. 143-158AustraliaDiamond morphology
DS1988-0326
1988
Jaques, A.L.Jaques, A.L.Non-volcanic sources of diamond; subducted Eclogites and peridotitemassifs?B.m.r. Research Newsletter, No. 9, pp. 12-13AustraliaEclogite, Peridotite
DS1989-0421
1989
Jaques, A.L.Fielding, D.C., Jaques, A.L.Geology, petrology and geochemistry of the Bow Hill lamprophyre dikes, Western AustraliaGeological Society of Australia Inc. Blackwell Scientific Publishing, Special, No. 14, Vol. 1, pp. 206-219AustraliaDeposit -Bow Hill, Lamprophyre
DS1989-0700
1989
Jaques, A.L.Jaques, A.L.Diamonds and their host rocks, and the relationship of alkaline Igneous rocks to mineral depositsBmr 89 Yearbook, Canberra, July 1 1988- June 30, 1989, pp. 85-88AustraliaBrief overview of project, Alkaline rocks
DS1989-0701
1989
Jaques, A.L.Jaques, A.L.The West Australian lamproites; multiple tapping of old enriched subcontinental lithosphereNew Mexico Bureau of Mines Bulletin., Continental Magmatism Abstract Volume, Held, Bulletin. No. 131, p. 143. AbstractAustraliaLamproite
DS1989-0702
1989
Jaques, A.L.Jaques, A.L.Lamproitic diamonds and their inclusions:new insights from the West Australia deposits #1Australian National University, Seminar abstract, 1p. (abstract.)AustraliaLamproite, Diamond inclusions
DS1989-0703
1989
Jaques, A.L.Jaques, A.L.Lamproitic diamonds and their inclusions: new insights from the West Australian deposits #2Diamond Workshop, International Geological Congress, July 15-16th., pp. 36-39. AbstractAustraliaLamproite, Diamond morphology - incl
DS1989-0704
1989
Jaques, A.L.Jaques, A.L., Haggerty, S.E., Lucas, H., Boxer, G.L.Mineralogy and petrology of the Argyle (AK1) lamproite pipe, westernAustraliaGeological Society of Australia Inc. Blackwell Scientific Publishing, Special, No. 14, Vol. 1, pp. 153-169AustraliaDeposit -Argyle, Lamproite
DS1989-0705
1989
Jaques, A.L.Jaques, A.L., Hall, A.E., Sheraton, J.W., Smith, C.B., Sun, S-S.Composition of crystalline inclusions and C-isotopic composition of Argyle and Ellendale diamondsGeological Society of Australia Inc. Blackwell Scientific Publishing, Special, No. 14, Vol. 2, pp. 966-989AustraliaDeposit -Argyle, Ellendale, Diamond inclusions
DS1989-0706
1989
Jaques, A.L.Jaques, A.L., Hall, A.E., Sheraton, J.W., Smith, Chris B., Sun, S-S.Nature and origin of West Australian diamonds: evidence from mineral inclusions and C-isotopic compositionsMinpet 89 Mineralogy And Petrology Symposium Held Sydney, February, p. 11. AbstractAustraliaDiamond morphology, Inclusions
DS1989-0707
1989
Jaques, A.L.Jaques, A.L., Kerr, I.D., Lucas, H., Sun, S-S., Chappell, B.W.Mineralogy and petrology of picritic monchiquites from Wandagee, CarnarvonBasin, western AustraliaGeological Society of Australia Inc. Blackwell Scientific Publishing, Special, No. 14, Vol. 1, pp. 120-138AustraliaPicrites, Mineralogy, petrology
DS1989-0708
1989
Jaques, A.L.Jaques, A.L., Sun, S-S., Chappell, B.W.Geochemistry of the Argyle (AK1) lamproite pipe, Western AustraliaGeological Society of Australia Inc. Blackwell Scientific Publishing, Special, No. 14, Vol. 1, pp. 170-188AustraliaDeposit -Argyle, Lamproite
DS1990-0757
1990
Jaques, A.L.Jaques, A.L.Diamondiferous lamproites of western AustraliaGeological Society of Australia Abstracts, No. 25, No. A12.11 pp. 242-243. AbstractAustraliaLamproites, Argyle, Ellendale
DS1990-0758
1990
Jaques, A.L.Jaques, A.L., O'Neill, H. St., Smith, C.B., Moon, J., ChappellDiamondiferous peridotite xenoliths from the Argyle(AKl) lamproite @Western AustraliaContributions to Mineralogy and Petrology, Vol. 104, No. 3, pp. 255-276AustraliaArgyle AKl lamproite, Xenoliths -peridotite
DS1990-0944
1990
Jaques, A.L.Liu, L.G., Mernagh, T.P., Jaques, A.L.A mineralogical raman-spectroscopy study on eclogitic garnet inclusions in diamonds from ArgyleContributions to Mineralogy and Petrology, Vol. 105, No. 2, pp. 156-161AustraliaSpectroscopy, Garnet analyses, Diamond inclusions
DS1990-1454
1990
Jaques, A.L.Taylor, W.R., Jaques, A.L., Ridd, M.Nitrogen defect aggregation characteristics of some Australasian diamonds:time-temperature constraints on the source regions of pipe and alluvialdiamondsAmerican Mineralogist, Vol. 75, No. 11-12, November-December pp. 1290-1310AustraliaDiamond morphology, Nitrogen
DS1991-0798
1991
Jaques, A.L.Jianxiong Zhou, Griffin, W.L., Jaques, A.L., Ryan, C.G., Win, T.T.Geochemistry of indicator minerals from Chinese kimberlites andlamproitesProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 475-477ChinaPyrope, chromite, ilmenite, LIMA, yimengite, Proton microprobe, EMP
DS1991-1653
1991
Jaques, A.L.Stachel, T., Lorenz, V., Smith, C.B., Jaques, A.L.Volcanology and geochemistry of the Ellendale lamproite field, WesternAustraliaProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 392-394AustraliaPetrogenesis, olivine lamproites, Leucite lamproites
DS1994-0467
1994
Jaques, A.L.Duggan, M.B., Jaques, A.L.Proterozoic shoshonitic lamprophyres from Tennant CreekGeological Society of Australia Abstract Volume, No. 37, pp. 87.AustraliaShoshonite, Lamprophyre, dikes
DS1994-0836
1994
Jaques, A.L.Jaques, A.L.A review of the alkaline rocks of Australia and related mineralizationGeological Society of Australia Abstract Volume, No. 37, pp. 195.AustraliaAlkaline rocks
DS1994-0837
1994
Jaques, A.L.Jaques, A.L.Diamonds in AustraliaSolomon and Groves, Mineral Deposits of Australia, Oxford, pp.787-820.AustraliaDiamond -occurrences, setting, Review paper
DS1994-0838
1994
Jaques, A.L.Jaques, A.L., Hall, A.E., Sheraton, J., Smith, C.B., Roksandic, Z.Peridotitic planar octahedral diamonds from the Ellendale lamproite Western Australia.Proceedings of Fifth International Kimberlite Conference, Vol. 2, pp. 69-77.AustraliaDiamond morphology, Deposit -Ellendale
DS1994-0839
1994
Jaques, A.L.Jaques, A.L., Wyborn, L.A.L., Gallagher, R.The role of geographic information systems, empirical modelling and expert systems in metallogenic research.Geological Society of Australia Abstracts, No. 37, p. 196-7.Australia, Western AustraliaGIS, Metallogeny, alkaline rocks
DS1994-1680
1994
Jaques, A.L.Stachel, T., Lorenz, V., Smith, C.B., Jaques, A.L.Evolution of four individual lamproite pipes, Ellendale volcanic field(Western Australia).Proceedings of Fifth International Kimberlite Conference, Vol. 1, pp. 177-194.AustraliaLamproite, Deposit -Ellendale
DS1994-1991
1994
Jaques, A.L.Zhou Jainxiong, Griffin, W.L., Jaques, A.L., Ryan, C.G., Win, T.T.Geochemistry of diamond indicator minerals from ChinaProceedings of Fifth International Kimberlite Conference, Vol. 2, pp. 285-301.ChinaGeochemistry, Indicator minerals
DS1995-0877
1995
Jaques, A.L.Jaques, A.L.The alkaline rocks of Australia and related mineralizationUniversity of West. Australian Key Centre, held Feb. 15, 16th., 51p.AustraliaAlkaline rocks
DS1996-0392
1996
Jaques, A.L.Duggan, M.B., Jaques, A.L.Mineralogy and geochemistry of Proterozoic shoshonitic lamprophyres From the Tennant Creek Inlier.Australian Journal of Earth Sciences, Vol. 43, No. 3, June 1, pp. 269-278.AustraliaLamprophyres, Shoshonite
DS1997-0553
1997
Jaques, A.L.Jaques, A.L., Wellman, P., Whitaker, A., Wyborn, D.High - resolution geophysics in modern geological mappingAgso Journal, Australian Geology And Geophysics, Vol. 17, No. 2, pp. 159-174AustraliaGeophysics - airborne, Geological mapping
DS2002-0767
2002
Jaques, A.L.Jaques, A.L.Australian diamond exploration and potentialProspectors and Developers Conference, March 10, 1p. abstractAustraliaExploration - brief
DS2002-0768
2002
Jaques, A.L.Jaques, A.L., Jareth, S., Walshe, J.L.Mineral systems of Australia: an overview of resources, settings and processesAustralian Journal of Earth Sciences, Vol. 49,4,August pp. 623-60.AustraliaResources, tectonics, mentions diamonds
DS2002-0769
2002
Jaques, A.L.Jaques, A.L., Smith, C.B.The Argyle (AK) diamond deposit, Western AustraliaGeological Society of Australia Abstracts, Vol. 67, p. 264. abstract.Australia, WesternGeology, Deposit - Argyle
DS2003-0648
2003
Jaques, A.L.Jaques, A.L., Milligan, P.R.Patterns and controls on the distribution of diamond pipes in Australia8 Ikc Www.venuewest.com/8ikc/program.htm, Session 5, AbstractAustraliaTarget area selection, Overview
DS200412-0906
2003
Jaques, A.L.Jaques, A.L., Milligan, P.R.Patterns and controls on the distribution of diamond pipes in Australia.8 IKC Program, Session 5, AbstractAustraliaTarget area selection Overview
DS200412-0907
2004
Jaques, A.L.Jaques, A.L., Milligan, P.R.Patterns and controls on the distribution of Diamondiferous intrusions in Australia.Lithos, Vol. 77, 1-4, Sept. pp. 783-802.AustraliaExploration, geophysics, kimberlites, lamproites, gravi
DS200812-0518
2008
Jaques, A.L.Jaques, A.L.Australian carbonatites: their resources and geodynamic setting.9IKC.com, 3p. extended abstractAustraliaCarbonatite
DS201212-0552
2012
Jaques, A.L.Phillips, D., Clarke, W., Jaques, A.L.New Ar40/39Ar ages for the West Kimberley lamproites and implications for Australian plate geodynamics.10th. International Kimberlite Conference Feb. 6-11, Bangalore India, AbstractAustraliaGeochronology
DS201312-0794
2013
Jaques, A.L.Schulze, D., Harte, B., Page, F.Z., Valley, J.W., DeR Channer, D.M., Jaques, A.L.Anticorrelation between low d13c of eclogitic diamonds and high d180 of their coesite and garnet inclusions requires a subduction origin.Geology, Vol. No. 4, pp. 455-458.South America, Venezuela, Australia, Africa, BotswanaDeposit - Guaniamo, Arygle, Orapa
DS201412-0210
2014
Jaques, A.L.Downes, P.J., Demeny, A., Czuppon, G., Jaques, A.L., Verrall, M., Sweetapple, M., Adams, D., McNaughton, N.J., Gwalani, L.G., Griffin, B.J.Stable H-C-O isotope and trace element geochemistry of the Cummins Range carbonatite complex, Kimberley region western Australia: implications for hydrothermal REE mineralization, carbonatite evolution and mantle source regions.Mineralium Deposita, Vol. 49, p. 905-932.AustraliaCarbonatite
DS201602-0203
2016
Jaques, A.L.Downes, P.J., Dunkley, D.J., Fletcher, I.R., McNaughton, N.J., Rasmusson, B., Jaques, A.L., Verall, M., Sweetapple, M.T.Zirconolite, zircon and monazite-(Ce) U-Th-Pb age constraints on the emplacement, deformation and alteration history of the Cummins Range carbonatite complex, Halls Creek orogen, Kimberley region, Western Australia.Mineralogy and Petrology, In press available, 24p.AustraliaCarbonatite

Abstract: In situ SHRIMP U-Pb dating of zirconolite in clinopyroxenite from the Cummins Range Carbonatite Complex, situated in the southern Halls Creek Orogen, Kimberley region, Western Australia, has provided a reliable 207Pb/206Pb age of emplacement of 1009 ± 16 Ma. Variably metamict and recrystallised zircons from co-magmatic carbonatites, including a megacryst ~1.5 cm long, gave a range of ages from ~1043-998 Ma, reflecting partial isotopic resetting during post-emplacement deformation and alteration. Monazite-(Ce) in a strongly foliated dolomite carbonatite produced U-Th-Pb dates ranging from ~900-590 Ma. Although the monazite-(Ce) data cannot give any definitive ages, they clearly reflect a long history of hydrothermal alteration/recrystallisation, over at least 300 million years. This is consistent with the apparent resetting of the Rb-Sr and K-Ar isotopic systems by a post-emplacement thermal event at ~900 Ma during the intracratonic Yampi Orogeny. The emplacement of the Cummins Range Carbonatite Complex probably resulted from the reactivation of a deep crustal structure within the Halls Creek Orogen during the amalgamation of Proterozoic Australia with Rodinia over the period ~1000-950 Ma. This may have allowed an alkaline carbonated silicate magma that was parental to the Cummins Range carbonatites, and generated by redox and/or decompression partial melting of the asthenospheric mantle, to ascend from the base of the continental lithosphere along the lithospheric discontinuity constituted by the southern edge of the Halls Creek Orogen. There is no evidence of a link between the emplacement of the Cummins Range Carbonatite Complex and mafic large igneous province magmatism indicative of mantle plume activity. Rather, patterns of Proterozoic alkaline magmatism in the Kimberley Craton may have been controlled by changing plate motions during the Nuna-Rodinia supercontinent cycles (~1200-800 Ma).
DS201602-0213
2016
Jaques, A.L.Jaques, A.L.Major and trace element variations in oxide and titanate minerals in the West Kimberley lamproites, Western Australia.Mineralogy and Petrology, In press available, 39p.AustraliaLamproite

Abstract: New data are presented for groundmass chromian spinel, perovskite, ilmenite, and K-Ti-Ba-rich phases from the Miocene olivine and leucite lamproites of the West Kimberley region. The spinels range from early Ti-Al-Mg chromite through Ti-Mg chromite to Ti-chromite and, in Ellendale 4 and 9, Ti-Cr magnetite and Ti-magnetite. Most crystallized at 850-1220 °C and fO2 ~ MW + 1-2 log units except for Ellendale 4 and 9 spinels which underwent marked late oxidation at ~650-750 °C with fO2 increasing sharply to ~FMQ + 2-3 log units. Perovskite is ubiquitous in the olivine lamproites and the Walgidee Hills (WH) lamproite. Compositional features of the perovskite are a wide range in Cr, and high Sr, Nb, Th, and LREE contents with highly fractionated REE patterns (La/YbCN ~ 750-3000). Perovskite from WH defines an evolutionary trend of enrichment in Na, Sr, Y, Nb, U and REE, and depletion in Cr, Fe, and Th with magma fractionation. Late crystallizing WH perovskite shows a decrease in LREE due to relative depletion of LREE in residual magma by extended crystallization of perovskite (and apatite). Priderite ((K,Ba)(Ti,Fe3+)8O16) has low Mg and V, and a range in Cr contents which decrease with magma evolution. Jeppeite ((K,Ba)2(Ti,Fe)6O13), has higher Sr and Nb content than priderite. Both contain low Y and REEs. Wadeite (K2ZrSi3O9), a ubiquitous groundmass phase, has high Sc, Rb and Hf contents, and strongly LREE-depleted REE patterns with positive Ce anomalies. Noonkanbahite, a late crystallizing phase in WH, has low Cr and Ni, and high Sr, Nb and Y contents. REE patterns for noonkanbahite display high HREE, depleted MREE, enriched La-Ce-Pr, and a positive Eu anomaly.
DS201604-0609
2016
Jaques, A.L.Gwalani, L.G., Jaques, A.L., Downes, P.J., Chalapathi Rao, N.V.Kimberlites, lamproites, carbonatites and associated alkaline rocks: a tribute to the work of Rex T. Prider VolumeMineralogy and Petrology, in press available 5p.MantlePrider volume
DS201804-0674
2017
Jaques, A.L.Boxer, G.L., Jaques, A.L., Rayner, M.J.Argyle ( AK1) diamond deposit.Australian Ore Deposits, AusIMM Monograph 32, ed. Phillips, N., pp. 527-532.Australiadeposit - Argyle
DS201805-0982
2018
Jaques, A.L.Timmerman, S., Jaques, A.L., Weiss, Y., Harris, J.W.N delta 13 inclusion profiles of cloudy diamonds from Koffiefontein: evidence for formation by continuous Rayleigh fractionation and multiple fluids.Chemical Geology, Vol. 483, pp. 31-46.Africa, South Africadeposit - Koffiefontein
DS201807-1532
2018
Jaques, A.L.Timmerman, S., Honda, M., Phillips, D., Jaques, A.L., Harris, J.W.Noble gas geochemistry of fluid inclusions in South Africa diamonds: implications for the origin of diamond forming fluids. ( fibrous)Mineralogy and Petrology, 10.1007/ s710-018- 0603-x 15p.Africa, South Africadeposit - Finsch, De Beers Pool, Koffiefontein

Abstract: Fibrous diamond growth zones often contain abundant high-density fluid (HDF) inclusions and these provide the most direct information on diamond-forming fluids. Noble gases are incompatible elements and particularly useful in evaluating large-scale mantle processes. This study further constrains the evolution and origin of the HDFs by combining noble gas systematics with ?¹³C, N concentrations, and fluid inclusion compositions for 21 individual growth zones in 13 diamonds from the Finsch (n = 3), DeBeers Pool (n = 7), and Koffiefontein (n = 3) mines on the Kaapvaal Craton. C isotope compositions range from ?2.8 to ?8.6‰ and N contents vary between 268 and 867 at.ppm, except for one diamond with contents of <30 at.ppm N. Nine of the thirteen studied diamonds contained saline HDF inclusions, but the other four diamonds had carbonatitic or silicic HDF inclusions. Carbonatitic and silicic HDFs yielded low He concentrations, R/Ra (³He/?Hesample/³He/?Heair) values of 3.2–6.7, and low ??Ar/³?Ar ratios of 390–1940. Noble gas characteristics of carbonatitic-silicic HDFs appear consistent with a subducted sediment origin and interaction with eclogite. Saline HDFs are characterised by high He concentrations, with R/Ra mostly between 3.9 and 5.7, and a wide range in ??Ar/³?Ar ratios (389–30,200). The saline HDFs likely originated from subducted oceanic crust with low He but moderate Ar contents. Subsequent interaction of these saline HDFs with mantle peridotite could explain the increase in He concentrations and mantle-like He isotope composition, with the range in low to high ??Ar/³?Ar ratios dependent on the initial ³?Ar content and extent of lithosphere interaction. The observed negative correlation between ?He contents and R/Ra values in saline HDFs indicates significant in situ radiogenic ?He production. Noble gas geochemistry of fluid inclusions in South African diamonds: implications for the origin of diamond-forming fluids.
DS201808-1754
2018
Jaques, A.L.Jaques, A.L., Foley, S.F.Insights into the petrogenesis of the West Kimberley lamproites from trace elements in olivine.Mineralogy and Petrology, doi.org/10.1007/s00710-018-0612-9 19p.Australialamproites

Abstract: The Miocene lamproites of the West Kimberley region, Western Australia include olivine-leucite lamproites (?10 wt% MgO) containing olivine and leucite microphenocrysts, and diamondiferous olivine lamproites (20-30 wt% MgO) containing olivine phenocrysts and larger (1-10 mm) olivine as mantle xenocrysts and dunite micro-xenoliths. Olivine phenocrysts and thin (<100 ?m) magmatic rims define trends of decreasing Cr and Ni, and increasing Ca and Mn, with decreasing olivine Mg#, consistent with fractional crystallisation of olivine (and minor chromite). Many phenocrysts are zoned, and those with cores of similar Mg# and trace element abundances to the mantle xenocrysts may be xenocrysts overgrown by later olivine crystallised from the lamproite magma. Magmatic olivines Mg#91-92 are estimated to have been in equilibrium with olivine lamproite magma(s) containing ~22-24 wt% MgO. The xenocrystic mantle olivines Mg90-92.5 in the olivine lamproites are inferred from trace element abundances to be mostly derived from garnet peridotite with equilibration temperatures estimated from the Al-in-olivine thermometer (Bussweiler et al. 2017) to be ~1000-1270 °C at depths of 115-190 km. Olivines from the deeper lithosphere are less depleted (lower Mg#, higher Na, Al, P, Ti, Zr etc) than those at shallower depths, a feature suggested to reflect the combined effects of metasomatic re-enrichment of the craton roots (Ti, Fe, Zr etc) and increasing temperature with depth of origin (Na, Al, Ca). The West Kimberley lamproite olivines are not enriched in Li, as might be expected if their source regions contained continental sedimentary material as has been previously inferred from lamproite large-ion-lithophile trace elements, and Sr and Pb isotopes.
DS201812-2799
2018
Jaques, A.L.Davy, A.T., Smith, C.B., Helmstaedt, H., Jaques, A.L.PrefaceSociety of Economic Geology Geoscience and Exploration of the Argyle, Bunder, Diavik, and Murowa Diamond Deposits, Special Publication no. 20, p. ixAustralia, India, Canada, Northwest Territories, Africa, Zimbabwedeposits - Argyle, Bunder, Diavik, Murowa
DS201812-2822
2018
Jaques, A.L.Jaques, A.L., Luguet, A., Smith, C.B., Pearson, D.G., Yaxley, G.M., Kobussen, A.F.Argyle deposit: Nature of the mantle beneath the Argyle AK1 lamproite pipe: constraints from mantle xenoliths, diamonds, and lamproite geochemistry.Society of Economic Geology Geoscience and Exploration of the Argyle, Bunder, Diavik, and Murowa Diamond Deposits, Special Publication no. 20, pp. 119-144.Australia, western Australiadeposit - Argyle
DS201812-2869
2018
Jaques, A.L.Rayner, M.J., Jaques, A.L., Boxer, G.L., Smith, C.B., Lorenz, V., Moss, S.W., Webb, K., Ford, D.Argyle deposit: The geology of the Argyle ( AK1) diamond deposit, western Australia.Society of Economic Geology Geoscience and Exploration of the Argyle, Bunder, Diavik, and Murowa Diamond Deposits, Special Publication no. 20, pp. 89-118.Australia, western Australiadeposit - Argyle
DS201905-1081
2019
Jaques, A.L.Timmerman, S., Jaques, A.L., Weiss, Y., Harris, J.W.N delta 13 C - inclusion profiles of cloudy diamonds from Koffiefontein: evidence for formation by continuous Rayleigh fractionation and multiple fluids.Chemical Geology, Vol. 483, pp. 31-46.Africa, South Africadeposit - Koffiefontein

Abstract: Six diamonds with a fibrous core, intermediate zone and monocrystalline outer zone (“cloudy diamonds”) from the Koffiefontein mine, South Africa, were investigated for N concentrations, carbon isotope compositions and micro-inclusion compositions along core to rim traverses. This study evaluates the nature of the change from fibrous to gem diamond growth and the relation between major element composition of high density fluid inclusions and N ? ?¹³C in fibrous growth zones. Three diamonds contain saline to carbonatitic fluid micro-inclusions with constant or increasing carbon isotope values which are inferred to have formed by varying amounts of Rayleigh fractionation in a closed system of a carbonate-bearing fluid. Continuous N ? ?¹³C fractionation trends from the fibrous to gem growth zone in two of the diamonds and equally low nitrogen aggregation states indicate formation of diamond shortly before kimberlite eruption from a single fluid without a time gap between fibrous and gem diamond growth. High major element/CO32- ratios in the growth media resulted in a constant major element composition of the fluid inclusions found in the studied fibrous diamonds. The transition from fibrous to gem diamond growth is likely caused by the precipitation of diamond reducing the degree of oversaturation of carbon in the fluid and hence decreasing the rate of diamond growth. Two other diamonds have inclusions that change from silicate minerals in the inner fibrous growth zones towards pure saline fluid compositions in the outer fibrous growth zones. This decrease in Si, Mg and Ca and increase in K and Cl in the inclusions is accompanied by a decrease in ?¹³C values and N contents. These trends are suggested to be the result from gradually mixing in more saline fluids with lower ?¹³C values. One diamond with silicic inclusions has significant N aggregation into B-centres, suggesting this fluid is different and that diamond formation occurred significantly (e.g. 1250 °C gives ?10 Ma) before the kimberlite eruption.
DS201906-1355
2019
Jaques, A.L.Timmerman, S., Yeow, H., Honda, M., Howell, D., Jaques, A.L., Krebs, M.Y., Woodland, S., Pearson, D.G., Avila, J.N., Ireland, T.R.U-Th/He systematics of fluid rich 'fibrous' diamonds - evidence for pre- and syn-kimberlite eruption ages.Chemical Geology, Vol. 515, pp. 22-36.Africa, Democratic Republic of Congo, Botswanadeposit - Jwaneng

Abstract: The physical characteristics and impermeability of diamonds allow them to retain radiogenic 4He produced in-situ from radioactive decay of U, Th and Sm. This study investigates the U-Th/He systematics of fibrous diamonds and provides a first step in quantification of the uncertainties associated with determining the in-situ produced radiogenic 4He concentration. Factors determining the total amount of measured helium in a diamond are the initial trapped 4He, the in-situ produced radiogenic 4He, ?-implantation, ?-ejection, diffusion, and cosmogenic 3He production. Alpha implantation is negligible, and diffusion is slow, but the cosmogenic 3He component can be significant for alluvial diamonds as the recovery depth is unknown. Therefore, samples were grouped based on similar major and trace element compositions to determine possible genetically related samples. A correlation between the 4He and U-Th concentrations approximates the initial 4He concentration at the axis-intersect and age as the slope. In this study, the corrections were applied to eight fibrous cubic diamonds from the Democratic Republic of the Congo and two diamonds from the Jwaneng kimberlite in Botswana. A correlation exists between the 4He and U-Th concentrations of the group ZRC2, 3, and 6, and of the group CNG2, 3, and 4 and both correlations deviate significantly from a 71?Ma kimberlite eruption isochron. The U-Th/He dating method appears a promising new approach to date metasomatic fluid events that result in fibrous diamond formation and this is the first evidence that some fibrous diamonds can be formed 10s to 100s Myr before the kimberlite eruption.
DS201908-1818
2019
Jaques, A.L.Timmerman, S., Honda, M., Zhang, X., Jaques, A.L., Bulanova, G., Smith, C.B., Burnham, A.D.Contrasting noble gas compositions of peridotitic and eclogitic monocrystalline diamonds from the Argyle lamproite, Western Australia.Lithos, Vol. 344-345, pp. 193-206.Australiadeposit - Argyle

Abstract: He-Ne-Ar compositions were determined in diamonds from the Argyle lamproite, Western Australia, to assess whether subducted material affects the noble gas budget and composition of stable old sub-continental lithospheric mantle (SCLM). Twenty diamonds (both peridotitic and eclogitic) were characterized for their carbon isotopic compositions and N abundance and aggregation from which 10 eclogitic growth zones and 5 peridotitic growth zones were analysed for their He-Ne-Ar compositions. The eclogitic diamonds have ?13C values of ?4.7 to ?16.6‰ indicating a subduction signature, whereas the peridotitic diamonds have mantle-like compositions of ?4.0 to ?7.8‰. Mantle residence temperatures based on N-in-diamond thermometry showed that the eclogitic diamonds were mainly formed at 1260-1270?°C or above 1300?°C near the base of the lithosphere, whereas the peridotitic diamonds generally formed at lower temperatures (mostly 1135-1230?°C). A noble gas subduction signature is present to various extents in the eclogitic diamonds and is inferred from a hyperbolic mixing relationship between R/Ra and 4He and ?13C values concentrations with a predominance of low R/Ra values (<0.5; R/Ra?=?3He/4Hesample/3He/4Heair). In addition, low 40Ar/4He and 40Ar/36Ar ratios, high nucleogenic 21Ne/4He and low 3He/22Ne ratios are characteristic of subducted material and were found in the eclogitic diamonds. The peridotitic diamonds show generally higher R/Ra values (median 1.1?±?1.1) and lower 4He/40Ar ratios compared to eclogitic diamonds (median 0.1?±?0.8 R/Ra; with 7/10 samples having an average of 0.13?±?0.14 R/Ra). The studied peridotitic diamond growth zones showed a negative correlation between R/Ra and 4He concentrations over 2 orders of magnitude and limited variation in 3He, that can be largely explained by radiogenic 4He ingrowth. At low 4He concentrations the R/Ra value is around 2.8 for both paragenesis of diamonds and is significantly lower than present-day SCLM values, suggesting (1) a more radiogenic helium isotope composition beneath the Halls Creek Orogen than those for typical SCLM from other cratons and/or (2) that the peridotitic diamonds are formed from fluids that also had a subduction input. The high mantle residence temperature and low R/Ra value in the core and low temperature and higher R/Ra value in the rim of a single peridotitic diamond indicate multiple growth events and that part of the lherzolitic diamond population may be genetically related to the eclogitic diamonds. Combining the diamond mantle residence temperatures with noble gas compositions shows that noble gas subduction signatures are present at the base of the lithosphere below 180?km depth beneath Argyle and that fluid migration and interaction with the SCLM occurred over scales of at least 15?km, between 180 and 165?km depth.
DS201909-2098
2019
Jaques, A.L.Timmerman, S., Honda, M., Burnham, A.D., Amelin, Y., Woodland, S., Pearson, D.G., Jaques, A.L., Le Losq, C., Bennett, V.C., Bulanova, G.P., Smith, C.B., Harris, J.W., Tohver, E.Primordial and recycled helium isotope signatures in the mantle transition zone. Science, Vol. 365, 6454, pp. 692-694.Mantlediamond genesis

Abstract: Isotope compositions of basalts provide information about the chemical reservoirs in Earth’s interior and play a critical role in defining models of Earth’s structure. However, the helium isotope signature of the mantle below depths of a few hundred kilometers has been difficult to measure directly. This information is a vital baseline for understanding helium isotopes in erupted basalts. We measured He-Sr-Pb isotope ratios in superdeep diamond fluid inclusions from the transition zone (depth of 410 to 660 kilometers) unaffected by degassing and shallow crustal contamination. We found extreme He-C-Pb-Sr isotope variability, with high 3He/4He ratios related to higher helium concentrations. This indicates that a less degassed, high-3He/4He deep mantle source infiltrates the transition zone, where it interacts with recycled material, creating the diverse compositions recorded in ocean island basalts.
DS202004-0519
2020
Jaques, A.L.Howell, D., Stachel, T., Stern, R.A., Pearson, D.G., Nestola, F., Hardman, M.F., Harris, J.W., Jaques, A.L., Shirery, S.B., Cartigny, P., Smit, K.V., Aulbach, S., Brenker, F.E., Jacob, D.E., Thomassot, E., Walter, M.J., Navon, O.Deep carbon through time: Earth's diamond record and its implications for carbon cycling and fluid speciation in the mantle.(peridotite and eclogite used)Geochimica et Cosmochimica Acta, Vol. 275, pp. 99-122.Mantlecarbon

Abstract: Diamonds are unrivalled in their ability to record the mantle carbon cycle and mantle fO2 over a vast portion of Earth’s history. Diamonds’ inertness and antiquity means their carbon isotopic characteristics directly reflect their growth environment within the mantle as far back as ?3.5 Ga. This paper reports the results of a thorough secondary ion mass spectrometry (SIMS) carbon isotope and nitrogen concentration study, carried out on fragments of 144 diamond samples from various locations, from ?3.5 to 1.4 Ga for P [peridotitic]-type diamonds and 3.0 to 1.0 Ga for E [eclogitic]-type diamonds. The majority of the studied samples were from diamonds used to establish formation ages and thus provide a direct connection between the carbon isotope values, nitrogen contents and the formation ages. In total, 908 carbon isotope and nitrogen concentration measurements were obtained. The total ?¹³C data range from ?17.1 to ?1.9 ‰ (P = ?8.4 to ?1.9 ‰; E = ?17.1 to ?2.1‰) and N contents range from 0 to 3073 at. ppm (P = 0 to 3073 at. ppm; E = 1 to 2661 at. ppm). In general, there is no systematic variation with time in the mantle carbon isotope record since > 3 Ga. The mode in ?¹³C of peridotitic diamonds has been at ?5 (±2) ‰ since the earliest diamond growth ?3.5 Ga, and this mode is also observed in the eclogitic diamond record since ?3 Ga. The skewness of eclogitic diamonds’ ?¹³C distributions to more negative values, which the data establishes began around 3 Ga, is also consistent through time, with no global trends apparent. No isotopic and concentration trends were recorded within individual samples, indicating that, firstly, closed system fractionation trends are rare. This implies that diamonds typically grow in systems with high excess of carbon in the fluid (i.e. relative to the mass of the growing diamond). Any minerals included into diamond during the growth process are more likely to be isotopically reset at the time of diamond formation, meaning inclusion ages would be representative of the diamond growth event irrespective of whether they are syngenetic or protogenetic. Secondly, the lack of significant variation seen in the peridotitic diamonds studied is in keeping with modeling of Rayleigh isotopic fractionation in multicomponent systems (RIFMS) during isochemical diamond precipitation in harzburgitic mantle. The RIFMS model not only showed that in water-maximum fluids at constant depths along a geotherm, fractionation can only account for variations of <1‰, but also that the principal ?¹³C mode of ?5 ± 1‰ in the global harzburgitic diamond record occurs if the variation in fO2 is only 0.4 log units. Due to the wide age distribution of P-type diamonds, this leads to the conclusion that the speciation and oxygen fugacity of diamond forming fluids has been relatively consistent. The deep mantle has therefore generated fluids with near constant carbon speciation for 3.5 Ga.
DS202008-1400
2020
Jaques, A.L.Hoggard, M.J., Czarnota, K., Richards, F.D., Huston, D.L., Jaques, A.L., Ghelichkhan, S.Global distribution of sediment hosted metals controlled by craton edge stability. ( not specific to diamonds but of interest)Nature Geoscience, Vol. 13, pp. 504-510.Mantlelithospheric thickness

Abstract: Sustainable development and the transition to a clean-energy economy drives ever-increasing demand for base metals, substantially outstripping the discovery rate of new deposits and necessitating dramatic improvements in exploration success. Rifting of the continents has formed widespread sedimentary basins, some of which contain large quantities of copper, lead and zinc. Despite over a century of research, the geological structure responsible for the spatial distribution of such fertile regions remains enigmatic. Here, we use statistical tests to compare deposit locations with new maps of lithospheric thickness, which outline the base of tectonic plates. We find that 85% of sediment-hosted base metals, including all giant deposits (>10?megatonnes of metal), occur within 200?kilometres of the transition between thick and thin lithosphere. Rifting in this setting produces greater subsidence and lower basal heat flow, enlarging the depth extent of hydrothermal circulation available for forming giant deposits. Given that mineralization ages span the past two?billion?years, this observation implies long-term lithospheric edge stability and a genetic link between deep Earth processes and near-surface hydrothermal mineral systems. This discovery provides an unprecedented global framework for identifying fertile regions for targeted mineral exploration, reducing the search space for new deposits by two-thirds on this lithospheric thickness criterion alone.
DS202009-1633
2020
Jaques, A.L.Jaques, A.L., Brink, F., Chen, J.Magmatic haggertyite in olivine lamproites of the West Kimberley region, western Australia.The American Mineralogist, in press available, 31p. PdfAustralialamproites
DS202012-2222
2020
Jaques, A.L.Jaques, A.L., Brink, F., Chen, J.Magmatic haggertyite in olivine lamproites of the West Kimberley region, Western Australia.American Mineralogist, Vol. 105, pp. 1724-1733.Australialamproites

Abstract: We report the first occurrence of magmatic haggertyite (BaFe6Ti5MgO19) from the Miocene lamproites of the West Kimberley region of Western Australia. This contrasts with the metasomatic formation reported in an olivine lamproite host at the type locality, Prairie Creek, Arkansas. Haggertyite occurs in the groundmass of a diamondiferous olivine lamproite pipe in the Ellendale field, and within the large zoned Walgidee Hills lamproite where it forms part of an extensive suite of Ba- and K-bearing titanate and Ti-rich silicate minerals. The haggertyite co-exists with chromian spinel, perovskite, and ilmenite in the Ellendale lamproite, and with priderite and perovskite and, in one locality, with priderite, jeppeite, ilmenite, and perovskite, in the Walgidee Hills lamproite. Unlike priderite and perovskite, which are common groundmass phases in the Ellendale olivine lamproites and present throughout the Walgidee Hills lamproite, haggertyite appears restricted in its occurrence and crystallization interval, with sparse ilmenite apparently mostly crystallizing as an alternative phase. In the Walgidee Hills lamproite the haggertyite-bearing assemblage is succeeded by the Ba-titanate assemblage priderite plus jeppeite in the evolved central part of the body. The haggertyite in the main zone of the Walgidee Hills lamproite has an average composition of (Ba0.7K0.3)1.0(Ti5.0Fe3+2.1Cr0.1Fe2+3.8Mn0.2Mg0.6Na0.1)12O19 and is thus very similar to the original haggertyite described from xenoliths in the Prairie Creek lamproite apart from being poorer in Cr and Ni. Haggertyite in the groundmass of the Ellendale olivine lamproite and the central zone of the Walgidee Hills lamproite, in addition to variations in Mg and Cr, show significant variation in Ti and Fe contents and in calculated Fe3+ and Fe2+. A linear inverse relationship between Ti and Fe, and Ti and Fe3+, indicates that Fe3+ is accommodated by the coupled substitution Ti4+ + Fe2+ ? 2 Fe3+. A marked trend to higher Fe3+ in the haggertyite in Ellendale 9 olivine lamproite is ascribed to increasing oxidation during crystallization, with fO2 estimated from the olivine-spinel thermometer and oxygen barometer at Dlog FMQ = -1 to +3 at temperatures of 790-660 °C. The haggertyite in the central zone of the Walgidee Hills lamproite, in contrast, shows a marked trend to Fe2+ enrichment, which is associated with decreasing Fe in perovskite. This is inferred to indicate formation under more reducing conditions, but sufficiently oxidized to permit Fe3+ in co-existing priderite and jeppeite. Trace-element analysis by LA-ICP-MS shows the Walgidee Hills haggertyite contains minor amounts of Na, Si, Ca, V, Co, Zn, Sr, Zr, Nb, and Pb, and only traces of Al, P, Sc, Rb, REE, Hf, and Ta. Moreover, the haggertyite is preferentially enriched in certain lithophile (Ba, Sr), siderophile (Mn, Fe, Co, Ni), and chalcophile (Zn, Pb) elements relative to co-existing priderite. Haggertyite crystallization appears to be a consequence not only of the very high Ba, Ti, and K contents of the lamproite, but of relatively high-Fe concentrations and low temperatures in evolved olivine lamproite magma with the Fe3+/Fe2+ ratio determined by the prevailing fO2. The new data suggest that haggertyite might also be present but previously unrecognized in the evolved groundmass of other olivine lamproites. Haggertyite is one of an increasing number of new minerals in upper mantle rocks and volcanics derived from the upper mantle hosting large-ion-lithophile and high field strength cations.
DS202103-0414
2021
Jaques, A.L.Sudholz, Z.J., Yaxley, G.M., Jaques, A.L., Brey, G.P.Experimental recalibration of the Cr-in-clinpyroxene geobarometer: improved precision and reliability above 4.5 Gpa.Contributions to Mineralogy and Petrology, Vol. 176, 10.1007/s0041 0-020-01768-z 21p. PdfMantlegeothermometry

Abstract: The pressure dependence of the exchange of Cr between clinopyroxene and garnet in peridotite is applicable as a geobarometer for mantle-derived Cr-diopside xenocrysts and xenoliths. The most widely used calibration (Nimis and Taylor Contrib Miner Petrol 139: 541-554, 2000; herein NT00) performs well at pressures below 4.5 GPa, but has been shown to consistently underestimate pressures above 4.5 GPa. We have experimentally re-examined this exchange reaction over an extended pressure, temperature, and compositional range using multi-anvil, belt, and piston cylinder apparatuses. Twenty-nine experiments were completed between 3-7 GPa, and 1100-1400 °C in a variety of compositionally complex lherzolitic systems. These experiments are used in conjunction with several published experimental datasets to present a modified calibration of the widely-used NT00 Cr-in-clinopyroxene (Cr-in-cpx) single crystal geobarometer. Our updated calibration calculates P (GPa) as a function of T (K), CaCr Tschermak activity in clinopyroxene (acpxCaCrTs), and Cr/(Cr?+?Al) (Cr#) in clinopyroxene. Rearranging experimental results into a 2n polynomial using multiple linear regression found the following expression for pressure: P(GPa)=11.03+(?T(K) ln(acpxCaCrTs)×0.001088)+(1.526×ln(Cr#cpxT(K))) where Cr#cpx=(CrCr+Al), acpxCaCrTs=Cr?0.81?Cr#cpx?(Na+K), with all mineral components calculated assuming six oxygen anions per formula unit in clinopyroxene. Temperature (K) may be calculated through a variety of geothermometers, however, we recommend the NT00 single crystal, enstatite-in-clinopyroxene (en-in-cpx) geothermometer. The pressure uncertainty of our updated calibration has been propagated by incorporating all analytical and experimental uncertainties. We have found that pressure estimates below 4 GPa, between 4-6 GPa and above 6 GPa have associated uncertainties of 0.31, 0.35, and 0.41 GPa, respectively. Pressures calculated using our calibration of the Cr-in-cpx geobarometer are in good agreement between 2-7 GPa, and 900-1400 °C with those estimated from widely-used two-phase geobarometers based on the solubility of alumina in orthopyroxene coexisting with garnet. Application of our updated calibration to suites of well-equilibrated garnet lherzolite and garnet pyroxenite xenoliths and xenocrysts from the Diavik-Ekati kimberlite and the Argyle lamproite pipes confirm the accuracy and precision of our modified geobarometer, and show that PT estimates using our revised geobarometer result in systematically steeper paleogeotherms and higher estimates of the lithosphere?asthenosphere boundary compared with the original NT00 calibration.
DS202105-0794
2021
Jaques, A.L.Sudholz, Z.I., Yaxley, G.M., Jaques, A.L., Chen, J.Ni-in-garnet geothermometry in mantle rocks: a high pressure experimental recalibration between 1100 and 1325 C. ( diamond potential)Contributions to Mineralogy and Petrology, 176, 16p. PdfMantlegeothermobarometry

Abstract: The temperature-dependent exchange of Ni and Mg between garnet and olivine in mantle peridotite is an important geothermometer for determining temperature variations in the upper mantle and the diamond potential of kimberlites. Existing calibrations of the Ni-in-garnet geothermometer show considerable differences in estimated temperature above and below 1100 °C hindering its confident application. In this study, we present the results from new synthesis experiments conducted on a piston cylinder apparatus at 2.25-4.5 GPa and 1100-1325 °C. Our experimental approach was to equilibrate a Ni-free Cr-pyrope-rich garnet starting mixture made from sintered oxides with natural olivine capsules (Niolv ? 3000 ppm) to produce an experimental charge comprised entirely of peridotitic pyrope garnet with trace abundances of Ni (10-100 s of ppm). Experimental runs products were analysed by wave-length dispersive electron probe microanalysis (EPMA) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). We use the partition coefficient for the distribution of Ni between our garnet experimental charge and the olivine capsule (lnDNigrt/olv;NigrtNiolv), the Ca mole fraction in garnet (XCagrt; Ca/(Ca?+?Fe?+?Mg)), and the Cr mole fraction in garnet (XCrgrt; Cr/(Cr?+?Al)) to develop a new formulation of the Ni-in-garnet geothermometer that performs more reliably on experimental and natural datasets than existing calibrations. Our updated Ni-in-garnet geothermometer is defined here as: T(?C)=?8254.568((XCagrt×3.023)+(XCrgrt×2.307)+(lnDNigrtolv?2.639))?273±55 where DNigrt/olv=NigrtNiolv, Ni is in ppm, XCagrt = Ca/(Ca?+?Fe?+?Mg) in garnet, and XCrgrt= Cr/(Cr?+?Al) in garnet. Our updated Ni-in-garnet geothermometer can be applied to garnet peridotite xenoliths or monomineralic garnet xenocrysts derived from disaggregation of a peridotite source. Our calibration can be used as a single grain geothermometer by assuming an average mantle olivine Ni concentration of 3000 ppm. To maximise the reliability of temperature estimates made from our Ni-in-garnet geothermometer, we provide users with a data quality protocol method which can be applied to all garnet EPMA and LA-ICP-MS analyses prior to Ni-in-garnet geothermometry. The temperature uncertainty of our updated calibration has been rigorously propagated by incorporating all analytical and experimental uncertainties. We have found that our Ni-in-garnet temperature estimates have a maximum associated uncertainty of ± 55 °C. The improved performance of our updated calibration is demonstrated through its application to previously published experimental datasets and on natural, well-characterised garnet peridotite xenoliths from a variety of published datasets, including the diamondiferous Diavik and Ekati kimberlite pipes from the Lac de Gras kimberlite field, Canada. Our new calibration better aligns temperature estimates using the Ni-in-garnet geothermometer with those estimated by the widely used (Nimis and Taylor, Contrib Mineral Petrol 139:541-554, 2000) enstatite-in-clinopyroxene geothermometer, and confirms an improvement in performance of the new calibration relative to existing versions of the Ni-in-garnet geothermometer.
DS202203-0372
2021
Jaques, A.L.Yaxley, G.M., Kjarsgaard, B.A., Jaques, A.L.Evolution of carbonatite magmas in the upper mantle and crust.Elements, Vol. 17, pp. 315-320.Mantlecarbonatite

Abstract: Carbonatites are the most silica-poor magmas known and are amongst Earth’s most enigmatic igneous rocks. They crystallise to rocks dominated by the carbonate minerals calcite and dolomite. We review models for carbonatite petrogenesis, including direct partial melting of mantle lithologies, exsolution from silica-undersaturated alkali silicate melts, or direct fractionation of carbonated silicate melts to carbonate-rich residual melts. We also briefly discuss carbonatite-mantle wall-rock reactions and other processes at mid- to upper crustal depths, including fenitisation, overprinting by carbohydrothermal fluids, and reaction between carbonatite melt and crustal lithologies.
DS202204-0515
2022
Jaques, A.L.Barrett, N., Jaques, A.L., Gonzalez-Alvarez, I., Walter, M.J., Pearson, G.Ultra-refractory peridotites of Phanerozoic mantle origin: the Papua New Guinea ophiolite mantle tectonites. ( harzburgites and peridotites)Journal of Petrology, 10.1093/petrology/egac014Asia, Papua New Guineaperidotites

Abstract: Harzburgites and dunites forming the base of the Late Cretaceous-Paleocene Papuan Ultramafic Belt (PUB) and Marum ophiolites of Papua New Guinea (PNG) are amongst the most refractory mantle peridotites on Earth. We present a new integrated dataset of major element, bulk plus mineral trace element and Re-Os isotopic analyses aimed at better understanding the genesis of these peridotites. The PUB harzburgites contain olivine (Fo92-93), low-Al enstatite (less than or equal to 0.5 wt. % Al2O3 and CaO), and Cr-rich spinel (Cr# = 0.90-0.95). The Marum harzburgites are less refractory with olivine (Fo91.9-92.7), enstatite (~0.5-1.0 wt. % Al2O3 and CaO), minor clinopyroxene (diopside), and spinel (Cr# = 0.71-0.77). These major element characteristics reflect equivalent or greater levels of melt depletion than that experienced by Archean cratonic peridotites. Whereas bulk-rock heavy rare earth element (HREE) abundances mirror the refractory character indicated by the mineral chemistry and major elements, large-ion lithophile elements (LILEs) indicate a more complex melting and metasomatic history. In-situ olivine and orthopyroxene REE measurements show that harzburgites and dunites have experienced distinct melt-rock interaction processes, with dunite channels/lenses, specifically, showing higher abundances of HREE in olivine. Distinctive severe inter-element fraction of platinum group elements and Re result in complex patterns that we refer to as “M-shaped”. These fractionated highly siderophile element (HSE) patterns likely reflect the dissolution of HSE-rich phases in highly depleted peridotites by interaction with subduction-related melts/fluids, possibly high-temperature boninites. Osmium isotope compositions of the PNG peridotites are variable (187Os/188Os = 0.1204 to 0.1611), but fall within the range of peridotites derived from Phanerozoic oceanic mantle, providing no support for ancient melt depletion, despite their refractory character. This provides further evidence that highly depleted peridotites can be produced in the modern Earth, in subduction zone environments. The complex geochemistry indicates a multi-stage process for the formation of the PNG mantle peridotites in a modern geodynamic environment. The first stage involves partial melting at low-pressure (<2 GPa) and high-temperature (~1250-1350 0C) to form low-K, low-Ti tholeiitic magmas that formed the overlying cumulate peridotite-gabbro and basalt (PUB only) sequences of the ophiolites. This is inferred to have occurred in a fore-arc setting at the initiation of subduction. Later stages involved fluxing of the residual harzburgites with hydrous fluids and melts to form replacive dunites and enstatite dykes, and interaction of the residual peridotites in the overlying mantle wedge with high-temperature hydrous melts from the subducting slab to generate the extremely refractory harzburgites. This latter stage can be linked to the eruption of low-Ca boninites at Cape Vogel, and other arc-related volcanics, in a nascent oceanic island arc. Both ophiolites were emplaced shortly after when the embryonic oceanic island arc collided with the Australian continent.
DS202205-0673
2022
Jaques, A.L.Barrett, N., Jaques, A.L., Gonzalqez-Alvarez, I., Walter, M.J., Pearson, G.Ultra-refractory peridotites of Phanerozoic mantle origin: the Papua New Guinea ophiolite mantle tectonites.Journal of Petrology, 10.1093/petrology/egac014 99p. pdf Asia, Papua New Guineatectonites

Abstract: Harzburgites and dunites forming the base of the Late Cretaceous-Paleocene Papuan Ultramafic Belt (PUB) and Marum ophiolites of Papua New Guinea (PNG) are among the most refractory mantle peridotites on Earth. We present a new integrated dataset of major element, bulk plus mineral trace element and Re-Os isotopic analyses aimed at better understanding the genesis of these peridotites. The PUB harzburgites contain olivine (Fo92-93), low-Al enstatite (less than or equal to 0.5 wt. % Al2O3 and CaO), and Cr-rich spinel (Cr#?=?0.90-0.95). The Marum harzburgites are less refractory with olivine (Fo91.9-92.7), enstatite (~0.5-1.0 wt. % Al2O3 and CaO), minor clinopyroxene (diopside), and spinel (Cr#?=?0.71-0.77). These major element characteristics reflect equivalent or greater levels of melt depletion than that experienced by Archean cratonic peridotites. Whereas bulk-rock heavy rare earth element (HREE) abundances mirror the refractory character indicated by the mineral chemistry and major elements, large-ion lithophile elements indicate a more complex melting and metasomatic history. In situ olivine and orthopyroxene REE measurements show that harzburgites and dunites have experienced distinct melt-rock interaction processes, with dunite channels/lenses, specifically, showing higher abundances of HREE in olivine. Distinctive severe inter-element fraction of platinum group elements and Re result in complex patterns that we refer to as ‘M-shaped’. These fractionated highly siderophile element (HSE) patterns likely reflect the dissolution of HSE-rich phases in highly depleted peridotites by interaction with subduction-related melts/fluids, possibly high-temperature boninites. Osmium isotope compositions of the PNG peridotites are variable (187Os/188Os?=?0.1204 to 0.1611), but fall within the range of peridotites derived from Phanerozoic oceanic mantle, providing no support for ancient melt depletion, despite their refractory character. This provides further evidence that highly depleted peridotites can be produced in the modern Earth, in subduction zone environments. The complex geochemistry indicates a multi-stage process for the formation of the PNG mantle peridotites in a modern geodynamic environment. The first stage involves partial melting at low-pressure (<2 GPa) and high-temperature (~1250°C-1350°C) to form low-K, low-Ti tholeiitic magmas that formed the overlying cumulate peridotite-gabbro and basalt (PUB only) sequences of the ophiolites. This is inferred to have occurred in a fore-arc setting at the initiation of subduction. Later stages involved fluxing of the residual harzburgites with hydrous fluids and melts to form replacive dunites and enstatite dykes and interaction of the residual peridotites in the overlying mantle wedge with high-temperature hydrous melts from the subducting slab to generate the extremely refractory harzburgites. This latter stage can be linked to the eruption of low-Ca boninites at Cape Vogel, and other arc-related volcanics, in a nascent oceanic island arc. Both ophiolites were emplaced shortly after when the embryonic oceanic island arc collided with the Australian continent.
DS1990-0759
1990
Jaques, L.Jaques, L.Finger-printing diamonds by their nitrogen aggregation stateBureau of Mineral Resources Research Newsletter, No. 12, April p. 12, 13AustraliaDiamond morphology, Nitrogen
DS1990-0760
1990
Jaques, L.Jaques, L.Do lamprophyres have high pressurerecious metal contents?Bureau of Mineral Resources Research Newsletter, No. 12, April pp. 17, 18AustraliaLamprophyres, Gold, silver
DS2003-0649
2003
Jaques, L.Jaques, L.Australian diamond exploration and potential 2002Pdac Abstract 2003, March 10, 1p.AustraliaNews item, Overview
DS200612-0641
2005
Jaques, L.Jaques, L.A new edition of the 1:5 million scale Australian diamond deposits, kimberlites and related rocks map.Geoscience Australia, AustraliaMap - kimberlites and lamproites
DS200612-1360
2006
Jaques, L.Stachel, T., Cartigny, P., Jaques, L.The deepest lithosphere and beyond: diamonds and related research, a session in honour of Jeff Harris.Goldschmidt Conference 16th. Annual, S5-01 theme abstract 1/8p. goldschmidt2006.orgMantleDiamond Inclusions
DS200712-0960
2007
Jaques, L.Schulze, D.J., Page, F.Z., Valley, J.W., Harte, B., Kita, N., Channer, D.M.,Jaques, L.Quasi-correlation between carbon and oxygen isotope signatures in eclogitic diamonds and their mineral inclusions.Geological Association of Canada, Gac-Mac Yellowknife 2007, May 23-25, Volume 32, 1 pg. abstract p.73-74.South America, Venezuela, Australia, Africa, BotswanaGeochronology
DS201809-2078
2018
Jaques, L.Rayner, M.J., Moss, S.W., Lorenz, V., Jaques, L., Boxer, G.L., Smith, C.B., Webb, K.New insights into volcanic processes from deep mining of the southern diatreme within the Argyle lamproite pipe, Western Australia.Mineralogy and Petrology, doi.org/10.1007/ s00710-018-0625-4 13p.Australia, Western Australiadeposit - Argyle

Abstract: Underground mining and deep drilling of the richly diamondiferous ~1.2 Ga Argyle lamproite in Western Australia has prompted a re-evaluation of the geology of the pipe. Argyle is considered to be a composite pipe that formed by the coalescence of several diatremes and has been offset and elongated by post-emplacement faulting. Recent geological studies have recognised at least five distinct volcaniclastic lamproite lithofacies with differing diamond grades. The new data suggest that the centre of the southern (main) diatreme is occupied by well-bedded, olivine lamproite lapilli tuff with very high diamond grades (>10 ct/t). Characteristic features include a clast-supported fabric and high modal abundance of densely packed lamproite lapilli and coarse-grained, likely mantle-derived olivine now replaced by serpentine and/or talc. The persistence of small-scale graded and cross-bedding in this lithofacies to depths of ~1.5 km below the original surface prior to erosion suggests phreatomagmatic volcanism forming the diatreme was syn-eruptively accompanied by subsidence of the tephra, maintaining a steep-walled diatreme in the water-saturated country rock sediments.
DS1997-0554
1997
Jarai, A.Jarai, A., Kozak, M., Rozsa, P.Comparison of the methods of rock microscopic grain size determination and quantitative analysisMath. Geol, Vol. 29, No. 8, Nov. pp. 977-992GlobalComputer, Grain size
DS2003-0865
2003
Jardim de Sa, E.F.Maiade Hollanda, M.H., Pimentel, M.M., Jardim de Sa, E.F.Paleoproterozoic subduction related metasomatic signatures in the lithospheric mantleJournal of South American Earth Sciences, Vol. 15, 8, pp. 885-900.Brazil, southeastSubduction, Alkaline rocks
DS200412-1204
2003
Jardim de Sa, E.F.Maiade Hollanda, M.H., Pimentel, M.M., Jardim de Sa, E.F.Paleoproterozoic subduction related metasomatic signatures in the lithospheric mantle beneath NE Brazil: inferences from trace eJournal of South American Earth Sciences, Vol. 15, 8,pp. 885-900.South America, BrazilSubduction Alkaline rocks
DS200712-0227
2007
Jardim De Sa, E.F.De Souza, Z.S., Martin, H., Peucat, J-J., Jardim De Sa, E.F., De Frietas Macedo, M.H.Calc alkaline magmatism at the Archean Proterozoic transition: the Caico Complex basement ( NE Brazil).Journal of Petrology, Vol. 48, 11, pp. 2149-2185.South America, Brazil, SeridoMagmatism
DS2000-0158
2000
Jardim deSaCid, J.P., Nardi, L.V.S., Conciecao, Bonin, Jardim deSaThe alkaline silica saturated ultrapotassic magmatism of the Riacho do Pontal Fold Belt.Journal of South American Earth Sciences, Vol. 13, No. 7, Dec. 1, pp. 661-683.Brazil, northeastAlkaline rocks - not specific to diamonds
DS2002-0768
2002
Jareth, S.Jaques, A.L., Jareth, S., Walshe, J.L.Mineral systems of Australia: an overview of resources, settings and processesAustralian Journal of Earth Sciences, Vol. 49,4,August pp. 623-60.AustraliaResources, tectonics, mentions diamonds
DS1996-0681
1996
Jargalsaihan, D.Jargalsaihan, D., et al.Guide to the geology and mineral resources of MongoliaGeological and Consulting Services, available in Canada, see priceGlobalBook -table of contents, Resources
DS1995-0878
1995
Jari, M.Jari, M.Effects of grinding and chemical factors on the generation and composition of the till fine fraction:Journal of Geochemical Exploration, Vol. 54, No.1, Aug. 15, pp. 49-62FinlandGeochemistry, Sampling -tills
DS1995-0879
1995
Jarick, J.Jarick, J., Brey, G.P., Keller, J.Isotopic and chemical composition of mega and phenocrysts: evidence for the petrogenesis of Hegau volProceedings of the Sixth International Kimberlite Conference Abstracts, pp. 263-265.EuropeAlkaline rocks
DS1988-0139
1988
Jark, W.Comelli, G., Stoehr, J., Jark, W., Pate, B.B.Extended x-ray absorption fine structure studies of diamond and graphitePhys. Rev. B. Condensed Matter, Vol. 37, No. 9, pp. 4383-4389GlobalBlank
DS1986-0403
1986
Jarmakani, G.E.Jarmakani, G.E.Discovering carbonatite in SyriaThe Syrian Journal of Geology, Vol. 11-12, pp. 31-35SyriaCarbonatite
DS1993-0519
1993
Jarnigan, L.Gentry, D.W., Jarnigan, L.Environmental aspects an increasing part of international mining projectsMining Engineering, Vol. 45, No. 8, August pp. 1009-1011GlobalEconomics, Environmental costs
DS1994-1334
1994
Jaroszewski, W.Park, R.G., Jaroszewski, W.Craton tectonics, stress and seismicityHancock, P.L. Continental Deformation, Pergamon pp. 200-222AfricaCraton, Tectonics
DS1994-1335
1994
Jaroszewski, W.Park, R.G., Jaroszewski, W.Craton tectonics, stress and seismicityHancock, P.L. Continental Deformation, Pergamon pp. 200-222.AfricaCraton, Tectonics
DS200712-1139
2006
Jarvie, D.M.Wei, Z., Moldowan, J.M., Jarvie, D.M., Hill, R.The fate of diamondoids in coals and sedimentary rocks.Geology, Vol. 34, 12, pp. 1013-1016.TechnologyDiamondoids
DS1989-1041
1989
Jarvis, G.T.Mitrovica, J.X., Beaumont, C., Jarvis, G.T.Tilting of continental interiors by the dynamical effects of subductionTectonics, Vol. 8, No. 5, October pp. 1079-1094MidcontinentTectonics, Structure
DS1993-0929
1993
Jarvis, G.T.Lowman, J.P., Jarvis, G.T.Mantle convection flow reversals due to continental collisionsGeophysical Research Letters, Vol. 20, No. 19, October 8, pp. 2087-2090.MantleTectonics
DS1999-0423
1999
Jarvis, G.T.Lowman, J.P., Jarvis, G.T.Effects of mantle heat source distribution on supercontinent stabilityJournal of Geophysical Research, Vol. 104, No.6, June 10, pp. 12733-46.MantleHot spot, Geodyanmics
DS2000-0444
2000
Jarvis, G.T.Jarvis, G.T.Foundering of truncated slabs below continental suture zonesGeological Association of Canada (GAC)/Mineralogical Association of Canada (MAC) 2000 Conference, 1p. abstract.Mantle, IndiaSubduction
DS200412-0252
2004
Jarvis, G.T.Butler, S.L., Jarvis, G.T.Stresses induced in continental lithospheres by axisymmetric spherical convection.Geophysical Journal International, Vol. 157, 3, pp. 1359-1376.MantleGeophysics - seismics, tectonics
DS200512-0475
2005
Jarvis, G.T.Jarvis, G.T., Lowman, J.P.Sinking slabs below fossil subduction zones.Physics of the Earth and Planetary Interiors, Vol. 152, pp. 103-115.MantleSubduction
DS200512-0556
2005
Jarvis, G.T.Koglin, D.E.Jr., Ghias, S.R., King, S.D., Jarvis, G.T., Lowman, J.P.Mantle convection with reversing mobile plates: a benchmark study.Geochemistry, Geophysics, Geosystems: G3, Vol. 6, doi. 10.1029/2005 GC000924MantleTectonics, convection
DS200712-0487
2007
Jarvis, G.T.Jarvis, G.T., Lowman, J.P.Survival times of subducted slab remnants in numerical models of mantle flow.Earth and Planetary Science Letters, Vol. 260, 1-2, pp. 23-36.MantleSubduction
DS200712-0488
2007
Jarvis, G.T.Jarvis, G.T., Lowman, J.P.Survival times of subducted slab remnants in numerical models of mantle flow.Earth and Planetary Science Letters, Vol. 260, 1-2, pp. 23-36.MantleSubduction
DS200712-0489
2007
Jarvis, G.T.Jarvis, G.T., Lowman, J.P.Survival times of subducted slab remnants in numerical models of mantle flow.Earth and Planetary Science Letters, Vol. 260, 1-2, pp. 23-36.MantleSubduction
DS200712-0967
2007
Jarvis, G.T.Shahnas, M.H., Jarvis, G.T.On the relative importance of mineral phase transitions and viscosity stratification in controlling the sinking rates of detached slab remnants.Geophysical Research Letters, Vol. 34, 11, June 16, L11302MantleSlab
DS200812-0402
2007
Jarvis, G.T.Ghias, S.R., Jarvis, G.T.Mantle flow reversals in cylindrical Earth models.Physics of the Earth and Planetary Interiors, Vol. 165, 3-4, pp. 194-207.MantleModeling
DS200812-0403
2008
Jarvis, G.T.Ghias, S.R., Jarvis, G.T.Mantle convection models with temperature and depth dependent thermal expansivity.Journal of Geophysical Research, Vol. 113, B8, B80408.MantleConvection
DS200812-0404
2008
Jarvis, G.T.Ghias, S.R., Jarvis, G.T.Mantle convection models with temperature and depth dependent thermal expansivity.Journal of Geophysical Research, Vol. 113, August 15, B08408MantleConvection
DS1992-0780
1992
Jarvis, I.Jarvis, I., Jarvis, K.E.Plasma spectrometry in the earth sciences: techniques, applications and future trendsChemical Geology, Vol. 95, No. 1-2, January 1, pp. 1-34GlobalSpectrometry -plasma, Overview, applications
DS1998-0954
1998
Jarvis, K.Mason, P.R.D., Downes, H., Jarvis, K., Vannucci, R.An investigation of incompatible trace elements in Massif Central mantle xenoliths by laser ablation.7th International Kimberlite Conference Abstract, pp. 549-1MantleGeochemistry - ICP-MS, Xenoliths -light rare earth element (LREE).
DS200912-0148
2009
Jarvis, K.Daniel de Liz, J., Stoll Nardi, L.V., Fernandes de Lima, E., Jarvis, K.The trace element record in zircon from the Lavras do Sul shoshonitic association, southernmost Brazil.The Canadian Mineralogist, Vol. 47, 4, August pp. 833-846.South America, BrazilShoshonite
DS1992-0780
1992
Jarvis, K.E.Jarvis, I., Jarvis, K.E.Plasma spectrometry in the earth sciences: techniques, applications and future trendsChemical Geology, Vol. 95, No. 1-2, January 1, pp. 1-34GlobalSpectrometry -plasma, Overview, applications
DS1993-0740
1993
Jarvis, K.E.Jarvis, K.E., Williams, J.G.Laser ablation inductively coupled plasma mass spectrometry(LA-ICP-MS):rapid technique direct quantitative determination major, trace rareearth elementsChemical Geology, Vol. 106, pp. 251-262GlobalSpectrometry, Geochemistry
DS1993-0384
1993
Jarvis, W.Duskin, D.J., Jarvis, W.Kimberlites in MichiganMid-continent diamonds Geological Association of Canada (GAC)-Mineralogical Association of Canada (MAC) Symposium ABSTRACT volume, held Edmonton May, pp. 99-100MichiganHistorical overview, Diamond exploration Program
DS1998-1653
1998
Jarvis, W.Zweistra, P., Jarvis, W., McGeorge, I.B.The geology of micaceous kimberlite intrusives, Khutse Botswana7th International Kimberlite Conference Abstract, pp. 1037-8.BotswanaMineral chemistry, petrography, Deposit - 173N, S, KO, 211
DS1999-0334
1999
Jarvis, W.Jarvis, W., McGeorge, I.B., Siamiasang, T.L.The mineral potential of BotswanaProspectors and Developers Association of Canada (PDAC) abstract volume, p. 8.BotswanaOverview
DS201312-0542
2013
Jarvis, W.Lisemann, J-E., Fuss, C., Jarvis, W., Russell, H.A.J., Kjarsgaard, B.A.K., Sharpe, D.R.As assessment of the structure, content and the usability of the kimberlite indicator and diamond database ( KIDD).2013 Yellowknife Geoscience Forum Abstracts, p. 39-40.CanadaDatabase - KIDD
DS201412-0275
2014
Jasiunas, A.Gaubas, E., Ceponis, T., Jasiunas, A., Kalendra, V., Pavlov, J., Kazuchits, N., Naumchik, E., Rusetsky, M.Lateral scan profiles of the recombination parameters correlated with distribution of grown-in impurities in HPHT diamond.Diamond and Related Materials, Vol. 47, pp. 15-26.TechnologySynthetics
DS1988-0327
1988
Jaskolla, F.Jaskolla, F., Henkel, J.Evaluation and digital processing of multispectral SPOT dataInternational Journal of Remote Sensing, Vol. 9, No. 10-11, Oct-Nov. pp. 1629-1638GlobalRemote Sensing, Computer -SPOT.
DS1994-0840
1994
Jasper, M.J.U.Jasper, M.J.U., Charlesworth, E.G., Stanistreet, I.G.Effects of oceanic closure and continental collision along Gariep belt LateProt./early Paleo Damara OrogenEconomic Geology Research Unit, Wits, No. 282, 34pSouth AfricaProterozoic, Damara Orogen
DS1995-0880
1995
Jasper, M.J.U.Jasper, M.J.U., Stanistreet, I.G., Charlesworth, E.G.Recognition of inversion tectonics within the Pan African Gariep Belt, Damara Orogen in southern NamibiaEconomic Research Unit University of Witwatersrand, No. 285, 15pNamibiaTectonics, Gariep Belt
DS1995-0881
1995
Jasper, M.J.U.Jasper, M.J.U., Stanistreet, I.G., Charlesworth, E.G.Recognition of inversion tectonics within the Pan African Gariep belt(Damara Orogen) in southern NamibiaEcon. Res. Unit, University of Witwatersrand, No. 285, 15p.NamibiaTectonics, Gariep Belt area
DS1996-0967
1996
Jaspersen, F.Z.Miller, R.R., Glen, J.D., Jaspersen, F.Z., Karmokolias, Y.International joint ventures in developing countries - happy marriages?International Finance Corp., Disc. Paper, No. 29, 26pGlobalEconomics, Joint ventures
DS201705-0837
2017
Jaszczak, J.A.Jaszczak, J.A., Dunnell, K.The Magnificent Mineralogy of Diamond.lithographie.org, No. 19, pp. 24-35.TechnologyBook - mineralogy
DS201706-1105
2017
Jauer, C.D.St. Onge, M.R., Harrison, J.C., Paul, D., Tella, S., Brent, T.A., Jauer, C.D., MacleanTectonic map of Arctic Canada (TeMAC): a first derivative product from Canada in 3-D geological compilation work.GAC annual meeting, 1p. AbstractCanadatectonics
DS1991-1425
1991
Jauffred, J.C.E.M.Rijks, E.J.H., Jauffred, J.C.E.M.Attribute extraction: an important application in any detailed 3-Dinterpretation studyGeophysics: the Leading Edge of Exploration, September pp. 11-19GlobalGeophysics -seismics, Three dimensional
DS200812-0773
2008
Jauhan, P.Mukhopadhyay, R., Rajesh, M., De, S., Chakraborty, B., Jauhan, P.Structural highs on the western continental slope of India: implications for regional tectonics.Geomorphology, Vol. 96, 1-2, pp. 48-61.IndiaTectonics
DS1992-0921
1992
Jault, D.Le Mouel, J.L., Courtillot, V., Jault, D.Changes in earth rotation rateNature, Vol. 355, January 2, pGlobalMantle, Geophysics -electromagnetics
DS2000-0615
2000
JaupartMareschal, J.C., Jaupart, Gariepy, Cheng et al.Heat flow and deep thermal structure near the southeastern edge of the Canadian Shield.Canadian Journal of Earth Sciences, Vol.37, No.2-3, Feb.Mar, pp.399-414.QuebecGeothermometry, Tectonics
DS201012-0323
2010
JaupartJavoy, M., Kaminski, E., Guyot,Andrault, Sanloup, Moreira, Labrosse, Jambon, Agrinier.Davaille, JaupartThe chemical composition of the Earth: enstatite chondrite models.Earth and Planetary Science Letters, Vol. 293, 3-4, pp. 259-268.MantleChemistry
DS1986-0103
1986
Jaupart, C.Brandeis, G., Jaupart, C.On the interaction between convection and crystallization in cooling magma chambersEarth and Planetary Science Letters, Vol. 77, No. 3-4, April pp. 345-361GlobalMantle
DS1989-0935
1989
Jaupart, C.Mareschal, J.C., Pinet, C., Gariepy, C., Jaupart, C., Bienfait, G., DallaNew heat flow density and radiogenic heat productiondat a in the Canadian Shield and the QuebecAppalachiansCanadian Journal of Earth Sciences, Vol. 26, No. 4, April pp. 845-852QuebecCraton, Heat Flow
DS1991-1355
1991
Jaupart, C.Pinet, C., Jaupart, C., Mareschal, J-C., Gariepy, C., Bienfait, G.Heat flow and structure of the lithosphere in the eastern Canadian shieldJournal of Geophysical Research, Vol. 96, No. B12, November 10, pp. 19, 941-19, 963OntarioHeat flow, Crust, greenstone belts
DS1995-0695
1995
Jaupart, C.Guillou, L., Jaupart, C.On the effect of continents on mantle convectionJournal of Geophysical Research, Vol. 100, No. B12, Dec. 10, pp. 24, 217-38MantleSubduction, Tectonics
DS1995-0696
1995
Jaupart, C.Guillou, L., Jaupart, C.On the effect of continents on mantle convectionJournal of Geophysical Research, Vol. 100, No. B12, Dec. 10, pp. 24, 217-238.Mantle, crustTectonics -review, Mantle convection
DS1995-0882
1995
Jaupart, C.Jaupart, C., Tait, S.Dynamics of differentiation in magma reservoirsJournal of Geophysical Research, Vol. 100, No. 9, Sept. 10, pp. 7615-36GlobalMagmatism, Layered intrusions
DS1996-0682
1996
Jaupart, C.Jaupart, C.Physical models of volcanic eruptionsChemical Geology, Vol. 128, pp. 217-227GlobalMagma, Volcanology -Mt. St. Helens
DS1996-1398
1996
Jaupart, C.Tait, S.R., Jaupart, C.The production of chemically stratified and accumulate plutonic igneousrocksMineralogical Magazine, Vol. 60, No. 1, Feb pp. 99-114GlobalMagmatic processes, Layered intrusive
DS1998-0714
1998
Jaupart, C.Kaminiski, E., Jaupart, C.The size distribution of pyroclasts and the fragmentation sequence in explosive volcanic eruptions.Journal of Geophysical Research, Vol. 103, No. 12, Dec. 10, pp. 29, 759-80.GlobalMagma - phreatomagmatic, General - not specific to diamonds
DS1999-0154
1999
Jaupart, C.Courtillot, V., Jaupart, C., Manighetti, TapponnierOn causal links between flood basalts and continental breakupEarth and Planetary Science Letters, Vol. 166, No. 3-4, Mar. pp. 177-196.GlobalBasalts, Tectonics
DS1999-0335
1999
Jaupart, C.Jaupart, C., Mareschal, J.C.The thermal structure and thickness of continental rootsLithos, Vol. 48, No. 1-4, Sept. pp. 93-114.MantleGeothermometry, Craton
DS2000-0463
2000
Jaupart, C.Kaminski, E., Jaupart, C.Lithospheric structure beneath the Phanerozoic intracratonic basins of North America.Earth and Planetary Science Letters, Vol. 178, No. 1-2, May 15, pp. 139-50.Canada, Northwest TerritoriesTectonics, Craton - basins
DS2002-0284
2002
Jaupart, C.Cheng, L.Z., Mareschal, J.C., Jaupart, C., Rolandone, F., Gariepy, C., RadigonSimultaneous inversion of gravity and heat flow data: constraints on thermal regimeJournal of Geodynamics, Vol. 34, 1, pp. 11-30.Ontario, ManitobaGeothermometry, Lithosphere - Abitibi subprovince, Thompson Belt
DS2002-1355
2002
Jaupart, C.Rolandone, F., Jaupart, C., Mareschal, J.C., Gariepy, C., Bienfait, G., CarbonneSurface heat flow, crustal temperatures and mantle heat flow in the Proterozoic TransJournal of Geophysical Research, Vol. 107, No. 12, Dec. 12, 10.1029/2001JB000698Northwest Territories, Alberta, Saskatchewan, OntarioGeothermometry, Heat flow - tectonics
DS2003-0192
2003
Jaupart, C.Burov, E., Jaupart, C., Guillou-Frottier, L.Ascent and emplacement of bouyant magma bodies in brittle ductile upper crustJournal of Geophysical Research, Vol. 108, B4, April 1, DOI 10.1029/2002JB001904.MantleMagmatism - not specific to diamonds
DS2003-1078
2003
Jaupart, C.Pinel, V., Jaupart, C.Magma chamber behaviour beneath a volcanic edificeJournal of Geophysical Research, Vol. 108, B2, 10.1029/2001JB001751MantleMagma - not specific to diamonds
DS2003-1177
2003
Jaupart, C.Rolandone, F., Mareschal, J.C., Jaupart, C., Gariepy, C., Bienfait, G., CarbonneSurface heat flow, crustal temperatures and mantle heat flow in the Proterozoic TransJournal of Geophysical Research, Vol. 107, 12, Dec. 6, pp. DO1 10.1029/2001JB000698OntarioGeothermometry
DS2003-1178
2003
Jaupart, C.Rolandone, F., Mareschal, J.C., Jaupart, C., Gosselin, C., Bienfait, G., LapointeHeat flow in the western Superior province of the Canadian ShieldJournal of Geophysical Research, Vol. 30, 12, June 15, 10.1029/2003GLO17386Ontario, Manitoba, SaskatchewanGeothermometry
DS200412-0249
2003
Jaupart, C.Burov, E., Jaupart, C., Guillou-Frottier, L.Ascent and emplacement of bouyant magma bodies in brittle ductile upper crust.Journal of Geophysical Research, Vol. 108, B4, April 1, DOI 10.1029/2002 JB001904.MantleMagmatism - not specific to diamonds
DS200412-0908
2003
Jaupart, C.Jaupart, C., Marescahl, J.C.Constraints on crustal heat production from heat flow data.Treatise on Geochemistry, Holland Editor, Volume 3, pp. 65-84.MantleGeothermometry
DS200412-1223
2004
Jaupart, C.Maraschal, J.C., Nyblade, A., Perry, H.K.C., Jaupart, C., Bienfait, G.Heat flow and deep lithospheric thermal structure at Lac de Gras Slave Province, Canada.Geophysical Research Letters, Vol. 31, 12, June 28, 10.1029/2004 GLO20133Canada, Northwest TerritoriesGeothermometry
DS200412-1224
2004
Jaupart, C.Mareschal, J.C., Jaupart, C.Variations of surface heat flow and lithospheric thermal structure beneath the North American craton.Earth and Planetary Science Letters, Vol. 223, 1-2, pp. 65-77.Canada, Northwest TerritoriesGeothermometry
DS200412-1682
2003
Jaupart, C.Rolandone, F., Mareschal, J.C., Jaupart, C., Gariepy, C., Bienfait, G., Carbonne, C., Lapointe, R.Surface heat flow, crustal temperatures and mantle heat flow in the Proterozoic Trans Hudson Orogen, Canadian Shield.Journal of Geophysical Research, Vol. 107, 12, Dec. 6, pp. DO1 10.1029/2001 JB000698Canada, OntarioGeothermometry
DS200412-1683
2003
Jaupart, C.Rolandone, F., Mareschal, J.C., Jaupart, C., Gosselin, C., Bienfait, G., Lapointe, R.Heat flow in the western Superior province of the Canadian Shield.Journal of Geophysical Research, Vol. 30, 12, June 15, 10.1029/2003 GLO17386Canada, Ontario, Manitoba, SaskatchewanGeothermometry
DS200512-0195
2004
Jaupart, C.Cottrell, E., Jaupart, C., Molnar, P.Marginal stability of thick continental lithosphere.Geophysical Research Letters, Vol. 31, 18, Sept. 28, 10.1029/2004 GLO20332MantleGeophsyics - seismics
DS200512-0494
2005
Jaupart, C.Jurine, D., Jaupart, C., Brandeis, G., Tackley, P.J.Penetration of mantle plumes through depleted lithosphere.Journal of Geophysical Research, Vol. 110, B10, B 10104 10.1029/2005 JB003751MantleTectonics
DS200512-0686
2005
Jaupart, C.Mareschal, J.C., Jaupart, C., Rolandone, F., Gariepy, C., Fowler, C.M., Bienfait, G., Carbonne, C., Lapointe, R.Heat flow, thermal regime, and elastic thickness of the lithosphere in the Trans-Hudson Orogen.Canadian Journal of Earth Sciences, Vol. 42, 4, April pp. 517-532.Canada, Northwest TerritoriesGeothermometry
DS200512-0846
2004
Jaupart, C.Perry, H.K.C., Jaupart, C., Mareschal, J.C., Rolandone, F., Bienfait, G.Heat flow in the Nipigon arm of the Keweenawan Rift, northwestern Ontario, Canada.Geophysical Research Letters, Vol. 31, 15,, L15607, DOI 1029/2004 GL020159Canada, OntarioGeothermometry
DS200612-0865
2005
Jaupart, C.Mareschal, J-C., Jaupart, C.Archean thermal regime and stabilization of the Craton.Benn, K., Mareschal, J-C., Condie, K.C. Archean Geodynamics and Environments, AGU Geophysical Monograph, No. 164, pp. 61-74.MantleGeothermometry
DS200612-0866
2006
Jaupart, C.Mareschal, J-C., Jaupart, C., Perry, H.K.C.Crustal evolution in North America recorded in heat production.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 12, abstract only.Mantle, North AmericaGeothermometry
DS200612-0916
2006
Jaupart, C.Michaut, C., Jaupart, C.Ultra rapid formation of large volumes of evolved magma.Earth and Planetary Science Letters, Vol. 250, 1-2, Oct. 15, pp. 38-52.MantleMagmatism, geothermometry, sills
DS200612-1078
2006
Jaupart, C.Perry, H.K.C., Jaupart, C., Mareschal, J.C., Bienfait, G.Crustal heat production in the Superior Province Canadian Shield and in North America inferred from heat flow data.Journal of Geophysical Research, Vol. 111, B4, B04401.Canada, Ontario, ManitobaGeothermometry
DS200612-1079
2006
Jaupart, C.Perry, H.K.C., Jaupart, C., Mareschal, J.C., Shapiro, N.M.Upper mantle velocity temperature conversion and composition determined from seismic refraction and heat flow.Journal of Geophysical Research, Vol. 111, B7 B07301MantleGeophysics - seismics
DS200612-1080
2006
Jaupart, C.Perry, H.K.C., Jaupart, C., Mareschal, J.C., Shapiro, N.M.Upper mantle velocity temperature conversion and composition determined from seismic.Journal of Geophysical Research, Vol. 111, B7, July 6, B07301, 14p.Mantle, Canada, OntarioGeophysics - seismics, Superior Province
DS200612-1081
2006
Jaupart, C.Perry, H.K.C., Jaupart, C., Mareschal, J-C., Bienfait, G.Crustal heat production in the Superior Province, Canadian Shield, and in North America.Journal of Geophysical Research, Vol. 111, No. B4, B04401Canada, Ontario, Manitoba, Saskatchewan, AlbertaGeothermometry
DS200612-1082
2006
Jaupart, C.Perry, H.K.C., Mareschal, J-C., Jaupart, C.Variations of strength and localized deformation in cratons: the 1.9 Ga Kapuskasing Uplift, Superior Province, Canada.Earth and Planetary Science Letters, In press - availableCanada, Ontario, ManitobaGeothermometry, craton, structural zone
DS200712-0591
2007
Jaupart, C.Labroose, S., Jaupart, C.Thermal evolution of the Earth: secular changes and fluctuations of plate characteristics.Earth and Planetary Science Letters, Vol. 260, 3-4, pp. 465-481.MantleDynamics, tectonics, geothermometry
DS200712-0723
2007
Jaupart, C.Michaut, C., Jaupart, C.Secular cooling and thermal structure of continental lithosphere.Earth and Planetary Science Letters, Vol. 257, 1-2, May 15, pp. 83-96.MantleGeothermometry
DS200712-0724
2007
Jaupart, C.Michaut, C., Jaupart, C., Bell, D.R.Transient geotherms in Archean continental lithosphere: new constraints on thickness and heat production of the subcontinental lithospheric mantle.Journal of Geophysical Research, Vol. 112, B4, B04408.Africa, South AfricaKaapvaal Craton
DS200912-0477
2009
Jaupart, C.Massol, H., Jaupart, C.Dynamics of magma flow near the vent: implications for dome eruptions.Earth and Planetary Science Letters, Vol. 279, 3-4, pp. 185-196.MantleMagmatism
DS200912-0499
2009
Jaupart, C.Michaut, C., Jaupart, C., Mareschal, J.C.Thermal evolution of cratonic roots.Lithos, Vol. 109, 1-2, pp. 47-60.MantleGeothermometry
DS200912-0743
2009
Jaupart, C.Taisne, B., Jaupart, C.Dike propagation through layered rocks.Journal of Geophysical Research, Vol. 114, B09203MantleSills - not specific to diamonds
DS201012-0437
2010
Jaupart, C.Levy, F., Jaupart, C., Mareschal, J-C., Bienfait, G., Limare, A.Low heat flux and large variations of lithospheric thickness in the Canadian Shield.Journal of Geophysical Research, Vol. 115, B6, B06404.CanadaGeophysics - seismics
DS201012-0574
2010
Jaupart, C.Perry, C., Rosieanu, C., Maraeschal, J-C., Jaupart, C.Thermal regime of the lithosphere in the Canadian shield.Canadian Journal of Earth Sciences, Vol. 47, 4, pp. 389-408.Canada, Northwest TerritoriesGeothermometry
DS201112-0479
2010
Jaupart, C.Jaupart, C., Mareschal, J-C.Heat generation and transport in the Earth.cambridge.org/us/earth, 978-0-521-89488-3 476p. $ 75.00GlobalBook - advertisement
DS201112-0588
2011
Jaupart, C.Levy, F., Jaupart, C.Temperature and rheological properties of the mantle beneath the North American craton from an analysis of heat flux and seismic data.Journal of Geophysical Research, Vol. 116, B01408, 25p.Canada, United StatesCraton, geothermometry
DS201112-0671
2011
Jaupart, C.Michaut, C., Jaupart, C.Two models for the formation of magma reservoirs by small increments.Tectonophysics, Vol. 500, 1-4, pp. 34-49.MantleMagmatism
DS201112-1023
2011
Jaupart, C.Taisne, B., Jaupart, C.Magma expansion and fragmentation in a propagating dyke.Earth and Planetary Science Letters, Vol. 301, 1-2, pp. 146-152.MantleMagmatism, dykes
DS201112-1024
2011
Jaupart, C.Taisne, B., Tait, S., Jaupart, C.Conditions for the arrest of a vertical propagating dyke.Bulletin of Volcanology, Vol. 73, 2, pp.MantleMagmatism
DS201212-0403
2012
Jaupart, C.Levy, F., Jaupart, C.The initiation of subduction by crustal extension at a continental margin.Geophysical Journal International, Vol. 188, 3, pp. 779-797.MantleSubduction
DS201212-0404
2012
Jaupart, C.Levy, F., Jaupart, C.The initiation of subduction by crustal extension at a continental margin.Geophysical Journal International, in press availableMantleSubduction
DS201609-1723
2016
Jaupart, C.Jaupart, C., Mareschal, J-C., Iarotsky, L.Radiogenic heat production in the continental crust.Lithos, Vol. 262, pp. 398-427.MantleThermometry

Abstract: Heat flow and heat production data complement seismic information and provide strong constraints on crustal composition, thickness and evolution. They have helped understand the nature of the Mohorovicic discontinuity and the variations in seismic velocities below the Moho. Notably, heat flow studies have delineated the vertical distribution of heat producing elements throughout the crust and in the upper most mantle lithosphere. Analysis of global data sets on heat flow and crustal thickness demonstrate that there is no correlation between these two variables. This is due to the large spatial variations in crustal composition and heat production that exist within a single geological province. For a given crustal thickness, the Moho temperature varies within a wide range (? 300 K) depending on surface heat flux and crustal heat production. Thus one cannot use generic models based on a “type” crustal column to calculate crustal geotherms. In stable regions, lower crustal temperatures depend on the amount and vertical distribution of heat producing elements in the crust. These temperatures determine the conditions of crustal stability and impose a limit on the maximum thickness of a stabilized crust.
DS201905-1048
2018
Jaupart, C.Jaupart, C., Mareschal, J-C., Roman, A.The formation of continental crust from a physics perspective.Geochemistry International, Vol. 56, 13, pp. 1289-1321.Mantlegeophysics

Abstract: The generation of crustal material and the formation of continental crust with a thickness of ?40 km involve different physical mechanisms operating over different time-scales and length-scales. This review focusses on the building of a thick crustal assemblage and on the vertical dimension where the consequences of gravity-driven processes are expressed most clearly. Continental crustal material is produced by a sequence of crust and mantle mlelting, fractionation of basaltic melts and sinking of dense mafic cumulates. The repeated operation of these mechanisms over tens of million years leads to a thick stably stratified crust. We evaluate the main mechanisms involved from a physics perspective and identify the key controls and constraints, with special attention to thermal requirements. To form magma reservoirs able to process significant magma volumes and to allow the foundering of mafic cumulates, melt must be fed locally at rates that are larger than that of average crustal growth. This requires the temporary focussing of magmatic activity in a few centers. In some cases, foundering of dense cumulates does not go to completion, leaving a deformed residual body bearing tell-tale traces of the process. Crust must be thicker than a threshold value in a 30-45 km range for mafic cumulates to sink into the mantle below the crust. Once that threshold thickness has been reached, further additions lead to increase the proportion of felsic material in the crust at the expense of mafic lithologies which disappear from the crust. This acts to enhance radiogenic heat production in the crust. One consequence is that crustal temperatures can be kept at high values in times of diminished melt input and also when magmatic activity stops altogether, which may lead to post-orogenic intracrustal melting and differentiation. Another consequence is that the crust becomes too weak mechanically to withstand the elevation difference with neighbouring terranes, which sets a limit on crustal thickening. The thermal structure of the evolving crust is a key constraint on the overall process and depends strongly on radiogenic heat production, which is surely one of the properties that make continental crust very distinctive. In the Archean Superior Province, Canada, the formation of juvenile continental crust and its thermal maturation 2.7 Gy ago can be tracked quite accurately and reproduced by calculations relying on the wealth of heat flow and heat production data available there. Physical models of magma ascent and storage favour the formation of magma reservoirs at shallow levels. This suggests that crustal growth proceeds mostly from the top down, with material that gets buried to increasingly large depths. Vertical growth is accompanied by lateral spreading in two different places. Within the crust, magma intrusions are bound to extend in the horizontal direction. Deeper down, lateral variations of Moho depth that develop due to the focussing of magmatic activity get relaxed by lower crustal flow. This review has not dealt with processes at the interface between the growing crust and the mantle, which may well be where dikes get initiated by mechanisms that have so far defied theoretical analyses. Research in this particular area is required to further our understanding of continental crust formation.
DS201912-2803
2019
Jaupart, C.Marty, B., Bekaert, D.V., Broadley, Jaupart, C.Geochemical evidence for high volatile fluxes from the mantle at the end of the Archean. (water, carbon dioxide, nitrogen and halogens)Nature, Vol. 575, pp. 485-488.Mantlemelting, convection

Abstract: The exchange of volatile species—water, carbon dioxide, nitrogen and halogens—between the mantle and the surface of the Earth has been a key driver of environmental changes throughout Earth’s history. Degassing of the mantle requires partial melting and is therefore linked to mantle convection, whose regime and vigour in the Earth’s distant past remain poorly constrained1,2. Here we present direct geochemical constraints on the flux of volatiles from the mantle. Atmospheric xenon has a monoisotopic excess of 129Xe, produced by the decay of extinct 129I. This excess was mainly acquired during Earth’s formation and early evolution3, but mantle degassing has also contributed 129Xe to the atmosphere through geological time. Atmospheric xenon trapped in samples from the Archaean eon shows a slight depletion of 129Xe relative to the modern composition4,5, which tends to disappear in more recent samples5,6. To reconcile this deficit in the Archaean atmosphere by mantle degassing would require the degassing rate of Earth at the end of the Archaean to be at least one order of magnitude higher than today. We demonstrate that such an intense activity could not have occurred within a plate tectonics regime. The most likely scenario is a relatively short (about 300 million years) burst of mantle activity at the end of the Archaean (around 2.5 billion years ago). This lends credence to models advocating a magmatic origin for drastic environmental changes during the Neoarchaean era, such as the Great Oxidation Event.
DS201312-0575
2013
Jaupart, V.Mareschal, J-C., Jaupart, V.Radiogenic heat production, thermal regime and evolution of continental crust.Tectonophysics, Vol. 609, pp. 524-534.MantleGeothermometry
DS1998-0688
1998
Jaupert, C.Jaupert, C., Mareschal, J.C., Davaille, A.Heat flow and thickness of the lithosphere in the Canadian ShieldJournal of Geophysical Research, Vol. 103, No. 7, Jul. 10, pp. 15269-86.Northwest Territories, Manitoba, Saskatchewan, AlbertaHeat flow, Mantle
DS2002-1046
2002
JaveriMelluso, L., Sethna, S.F., D'Antonio, M., Javeri, BennioGeochemistry and petrogenesis of sodic and potassic mafic alkaline rocks in the Deccan volcanic Province.Mineralogy and Petrology, Vol. 74, 2-4, pp. 323-42.IndiaAlkaline rocks, Deposit - Mumbai area
DS1998-0220
1998
JavoyCartigny, P., De Corte, Shatsky, Sobolev, JavoyMicrodiamonds from ultra high pressure (UHP) metamorphic rocks of the Kokchetav massif and bearing on carbon and nitrogen ...Mineralogical Magazine, Goldschmidt abstract, Vol. 62A, p. 276-7.RussiaSubduction, Deposit - Kokchetav
DS1998-0319
1998
JavoyDe Corte, K., Cartigny, P., Shatsky, Sobolev, JavoyEvidence of fluid inclusions in metamorphic microdiamonds from the Kokchetav Massif.Geochimica et Cosmochimica Acta, Vol. 62, No. 23/24, Dec. pp. 3765-73.Russia, KazakhstanMicrodiamonds, nitrogen, Deposit - Kokchetav Massif
DS2001-0162
2001
JavoyCartigny, P., Jendrzewski, N., Pineau, F., Petit, JavoyVolatile (Carbon,Nitrogen,Argon) variability in MORB and respective roles of mantle source heterogenity and degassing: caseEarth and Planetary Science Letters, Vol. 194, No. 1-2, pp. 241-57.Indian RidgeBasaltic glasses - geochemistry, Argon, Carbon, Nitrogen, MORB
DS1984-0383
1984
Javoy, M.Javoy, M., Pineau, F., Demaiffe, D.Nitrogen and Carbon Isotopic Composition in the Diamonds Of mbuji Mayi Zaire.Earth Plan. Sci. Letters, Vol. 68, No. 3, PP. 399-412.Central Africa, ZaireDiamond Morphology
DS1986-0404
1986
Javoy, M.Javoy, M., Pineau, F., Delorme, H.Carbon and nitrogen isotopes in the mantleChem. Geol, Vol. 57, No. 1-2, pp. 41-62GlobalKimberlite, Mantle
DS1988-0530
1988
Javoy, M.Ouzegane, K., Fourcade, S., Kienast, J.R., Javoy, M.New carbonatite complexes in the Archean In ouzzal nucleus(Ahaggar, Algeria)- mineralogical and geochemical dataContributions to Mineralogy and Petrology, Vol. 52, pp. 247-275AlgeriaCarbonatite
DS1990-1082
1990
Javoy, M.Nadeau, S., Pineau, F., Javoy, M., Francis, D.Carbon concentrations and isotopic ratios in fluid-inclusion bearing upper mantle xenoliths along the northwestern margin of North AmericaChemical Geology, Vol. 81, No. 4, February 20, pp. 271-298United StatesGeochemistry, Xenolith inclusions
DS1992-1281
1992
Javoy, M.Robert, F., Rejou-Michel, A., Javoy, M.Oxygen isotope homogeneity of the earth: new evidenceEarth and Planetary Science Letters, Vol. 108, No. 1/3. January pp. 1-10GlobalEarth, Geochronology
DS1993-1616
1993
Javoy, M.Trull, T., Nadeau, S., Pineau, F., Polve, M., Javoy, M.C-He systematics in hotspot xenoliths: implications for mantle carbon contents and carbon recycling.Earth and Planetary Science Letters, Vol. 118, No. 1-4, July, pp. 43-64.Mantle, Hawaii, Kerguelen Islands, IndiaXenoliths -Carbon and helium, Hotspots
DS1994-0203
1994
Javoy, M.Boyd, S.R., Pineau, F., Javoy, M.Modelling the growth of natural diamondsChemical Geology, Vol. 116, No. 1-2, Sept. 1, pp. 29-42.GlobalDiamond morphology, Diamond -natural
DS1998-0219
1998
Javoy, M.Cartigny, P., Boyd, S.R., Javoy, M.Nitrogen isotopes in peridotitic diamonds from Fuzian China: the mantlesignature.Terra Nova, Vol. 9, No. 4, pp. 175-179.ChinaMantle, Geochronology
DS1998-0221
1998
Javoy, M.Cartigny, P., Harris, J.W., Javoy, M.Eclogitic, peridotitic, metamorphic diamonds and the problems of carbonrecycling.7th International Kimberlite Conference Abstract, pp. 141-143.BotswanaDiamond genesis, carbon, Deposit - Orapa
DS1998-0222
1998
Javoy, M.Cartigny, P., Harris, J.W., Javoy, M.Eclogitic diamond formation at Jwaneng: no room for a recycled componentScience, Vol. 280, No. 5368, BotswanaEclogite - subduction, Deposit - Jwaneng
DS1998-0223
1998
Javoy, M.Cartigny, P., Harris, J.W., Javoy, M.Subduction related diamonds? the evidence for a mantle derived origin from coupled delta 13C -15N determin...Chemical Geology, Vol. 147, No. 1-2, May 15, pp. 147-160.Mantle, BotswanaDiamond genesis - subduction, Deposit - Jwaneng, Orapa
DS1998-0689
1998
Javoy, M.Javoy, M.The birth of the Earth's atmosphere: the behaviour and fate of its majorelementsChemical Geology, Vol. 147, No. 1-2, May 15, pp. 11-26.MantleChemistry
DS1998-0690
1998
Javoy, M.Javoy, M.Mechanism of core formation in the light of geochemical constraints and Of the great impactor hypothesis.Mineralogical Magazine, Goldschmidt abstract, Vol. 62A, p. 707-8.MantleGeochemistry
DS2001-0161
2001
Javoy, M.Cartigny, P., Harris, J.W., Javoy, M.Diamond genesis, mantle fractionations and mantle nitrogen content: a study of delta 13 C -N in diamondsEarth and Planetary Science Letters, Vol. 185, No. 1-2, Feb.15, pp.85-98.GlobalDiamond - genesis, morphology, nitrogen, ultra high pressure (UHP)
DS2002-0259
2002
Javoy, M.Cartigny, P., Harris, J.W., Javoy, M.New dat a from a new craton: N and C isotopes in diamonds from the PAnd a kimberlite, Canada.Eos, American Geophysical Union, Spring Abstract Volume, Vol.83,19, 1p.Northwest TerritoriesGeochronology, Deposit - Panda
DS2002-0770
2002
Javoy, M.Javoy, M., Pineau, F.Recycling volatile elements into the mantle18th. International Mineralogical Association Sept. 1-6, Edinburgh, abstract p.248.MantleTectonics - subduction volcanism
DS2003-0224
2003
Javoy, M.Cartigny, P., Stachel, T., Harris, J.W., Javoy, M.C and N stable isotope characteristics of diamonds from Namibia8 Ikc Www.venuewest.com/8ikc/program.htm, Session 2, AbstractNamibiaEclogites, diamonds, Geochronology
DS200412-0291
2003
Javoy, M.Cartigny, P., Harris, J.W., Taylor, A., Davies, R., Javoy, M.On the possibility of a kinetic fractionation of nitrogen stable isotopes during natural diamond growth.Geochimica et Cosmochimica Acta, Vol. 67, 8, pp. 1571-76.TechnologyDiamond morphology
DS200412-0292
2003
Javoy, M.Cartigny, P., Stachel, T., Harris, J.W., Javoy, M.C and N stable isotope characteristics of diamonds from Namibia.8 IKC Program, Session 2, AbstractAfrica, NamibiaEclogite, diamonds, geochronology
DS200412-0293
2004
Javoy, M.Cartigny, P., Stachel, T., Harris, J.W., Javoy, M.Constraining diamond metasomatic growth using C - and N stable isotopes: examples from Namibia.Lithos, Vol. 77, 1-4, Sept. pp. 359-373.Africa, NamibiaPlacers, alluvials, Nitrogen, metasomatism
DS200412-0942
2004
Javoy, M.Kadik, A., Pineau, F., Litvin, Y., Jendrzejewski, N., Martinez, I., Javoy, M.Formation of carbon and hydrogen species in magmas at low oxygen fugacity.Journal of Petrology, Vol. 45, 7, pp. 1297-1310.TechnologyMagmatism - not specific to diamonds
DS200612-0227
2006
Javoy, M.Cartigny, P., Pineau, F., Aubaud, C., Javoy, M.Carbon flux at mid-ocean ridges and CO2/Nb variability in the mantle.Geochimica et Cosmochimica Acta, Vol. 70, 18, 1, p. 87, abstract only.MantleCarbon chemistry
DS200912-0442
2006
Javoy, M.Litvin, Y., Pineau, F., Javoy, M.Carbon isotope fractionation during diamond synthesis in carbonatite carbon melts of natural chemistry ( experiments at 6.5-7.5 GPa).Geochemistry Conference, 1p, abstract onlyTechnologyGeochronology
DS201012-0323
2010
Javoy, M.Javoy, M., Kaminski, E., Guyot,Andrault, Sanloup, Moreira, Labrosse, Jambon, Agrinier.Davaille, JaupartThe chemical composition of the Earth: enstatite chondrite models.Earth and Planetary Science Letters, Vol. 293, 3-4, pp. 259-268.MantleChemistry
DS1989-0709
1989
Jaworowski, C.Jaworowski, C.Geomorphic evidence for neotectonism in central Wyoming, United States (US)Tectonophysics, Vol. 163, pp. 333-337WyomingTectonics, Sweetwater graben
DS1994-1181
1994
Jayaganapathy, S.Meyer, H.O.A., Mitchell, R.H., Jayaganapathy, S.Phlogopite in calc-alkaline lamprophyres of northern EnglandMineralogy and Petrology, Vol. 51, No. 2-4, pp. 227-237.GlobalLamprophyres
DS1996-0260
1996
Jayananda, M.Chardon, D., Choukroune, P., Jayananda, M.Strain patterns, decollement and incipient and subducted greenstoneterrains, Archean Dharwar CratonJournal of Structural Geology, Vol. 18, No. 8, Aug. 1, pp. 991-IndiaStructure, Dharwar Craton, Greenstone belts
DS2002-0276
2002
Jayananda, M.Chardon, D., Peucat, J.J., Jayananda, M., Choukroune, P., Fanning, C.M.Archean granite greenstone tectonics at Kolar South India: interplay of diapirism andTectonics, Vol. 21, 3, 7-1.IndiaMagmatism - not specific to diamonds
DS2003-0760
2003
Jayananda, M.Kumar, S.B.H., Jayananda, M., Kano, T., Swamy, N.S., Mahabaleswar, B.Late Archean juvenile magmatic accretion process in the eastern Dharwar Craton:Geological Society of India Memoir, No. 50, pp. 375-408.IndiaMagmatism
DS200412-1069
2003
Jayananda, M.Kumar, S.B.H., Jayananda, M., Kano, T., Swamy, N.S., Mahabaleswar, B.Late Archean juvenile magmatic accretion process in the eastern Dharwar Craton: Kuppam Karimangalam area.Geological Society of India Memoir, No. 50, pp. 375-408.IndiaMagmatism
DS200812-0008
2008
Jayananda, M.Ahmad, T., Jayananda, M.Plutonism and Precambrian magmatism in India.Glimpses of Geoscience Research in India, The Indian report to IUGS 2004-08, pp. 160-173.IndiaShield areas
DS200812-0203
2007
Jayananda, M.Chardon, D., Jayananda, M.3D field perspective on deformation, flow and growth of lower continental crust ( Dhwar craton, India).Tectonics, In press availableIndiaMagmatism
DS200812-0204
2008
Jayananda, M.Chardon, D., Jayananda, M.Three dimensional field perspective on deformation, flow and growth of the lower continental crust ( Dharwar Craton, India).Tectonics, Vol. 27 TC1014IndiaJuvenile magmatic accretion
DS200812-0205
2008
Jayananda, M.Chardon, D., Jayananda, M.Three dimensional field perspective on deformation, flow, and growth of the lower continental crust (Dharwar Craton, India).Tectonics, Vol. 27, 1, TC1014IndiaMantle accretion
DS201806-1229
2018
Jayananda, M.Jayananda, M., Santosh, M., Aadhiseshan, K.R.Formation of Archean (3600-2500 Ma) continental crust in the Dharwar craton, southern India.Earth Science Reviews, Vol. 181, pp. 12-42.Indiageodynamics

Abstract: The generation, preservation and destruction of continental crust on Earth is of wide interest in understanding the formation of continents, cratons and supercontinents as well as related mineral deposits. In this contribution, we integrate the available field, petrographic, geochronologic, elemental Nd-Hf-Pb isotope data for greenstones, TTG gneisses, sanukitoids and anatectic granites from the Dharwar Craton (southern India). This review allows us to evaluate the accretionary processes of juvenile crust, mechanisms of continental growth, and secular evolution of geodynamic processes through the 3600-2500?Ma window, hence providing important insights into building of continents in the Early Earth. The Dharwar Craton formed by assembly of micro-blocks with independent thermal records and accretionary histories. The craton can be divided into three crustal blocks (western, central and eastern) separated by major shear zones. The western block contains some of the oldest basement rocks with two generations of volcano-sedimentary greenstone sequences and discrete potassic plutons whereas the central block consist of older migmatitic TTGs, abundant younger transitional TTGs, remnants of ancient high grade supracrustal rocks, linear volcanic-dominated greenstone belts, voluminous calc-alkaline granitoids of sanukitoid affinity and anatectic granites. In contrast, the eastern block comprises younger transitional TTGs, abundant diatexites, thin volcanic-sedimentary greenstone belts and calc-alkaline plutons. Published geochronologic data show five major periods of felsic crust formation at ca. 3450-3300?Ma, 3230-3150?Ma, 3000-2960?Ma, 2700-2600?Ma, and 2560-2520?Ma which are sub-contemporaneous with the episodes of greenstone volcanism. U-Pb ages of inherited zircons in TTGs, as well as detrital zircons together with Nd-Pb-Hf isotope data, reveal continental records of 3800-3600?Ma. The U-Pb zircon data suggest at least four major reworking events during ca. 3200?Ma, 3000?Ma, 2620-2600?Ma, and 2530-2500?Ma corresponding to lower crustal melting and spatially linked high grade metamorphic events. The TTGs are sub-divided into the older (3450-3000?Ma) TTGs and the younger (2700-2600?Ma) transitional TTGs. The older TTGs can be further sub-divided into low-Al and high-Al groups. Elemental and isotopic data suggest that the low-Al type formed by melting of oceanic island arc crust within plagioclase stability field. In contrast, the elemental and isotopic features for the high-Al group suggest derivation of their magmatic precursor by melting of oceanic arc crust at deeper levels (55-65?km) with variable garnet and ilmenite in residue. The transitional TTGs likely formed by melting of composite sources involving both enriched oceanic arc crust and sub-arc mantle with minor contamination of ancient crustal components. The geochemical and isotopic compositions of granitoids with sanukitoid affinity suggest derivation from enriched mantle reservoirs. Finally, anatectic granites were produced by reworking of crustal sources with different histories. In the light of the data reviewed in this contribution, we propose the following scenario for the tectonic evolution of the Dharwar Craton. During 3450-3000?Ma, TTGs sources (oceanic arc crust) formed by melting of down going slabs and subsequent melting of such newly formed crust at different depths resulted in TTG magmas. On the contrary, by 2700?Ma the depth of slab melting increased. Melting of slab at greater depth alongside the detritus results in enriched melts partly modified the overlying mantle wedge. Subsequent melting of such newly formed enriched oceanic arc crust and surrounding arc-mantle generated the magmatic precursor to transitional TTGs. Finally at ca. 2600-2560?Ma, eventual breakoff of down going slab caused mantle upwelling which induced low degree (10-15%) melting of overlying enriched mantle at different depths, thereby, generating the sanukitoid magmas which upon emplacement into the crust caused high temperature metamorphism, reworking and final cratonization.
DS201905-1077
2018
Jayananda, M.Soderlund, U., Bleeker, W., Demirer, K., Srivastava, R.K., Hamilton, M., Nilsson, M., Personen, L.J., Samal, A.K., Jayananda, M., Ernst, R.E., Srinivas, M.Emplacement ages of Paleoproterozoic mafic dyke swarms in eastern Dharwar craton, India: implications for paleoreconstructions and support for a ~30 degree change in dyke trends from south to north.Precambrian Research, doi.org/10.1016/ j.precamres.2018.12.017Indiacraton

Abstract: Large igneous provinces (LIPs) and especially their dyke swarms are pivotal to reconstruction of ancient supercontinents. The Dharwar craton of southern Peninsular India represents a substantial portion of Archean crust and has been considered to be a principal constituent of Superia, Sclavia, Nuna/Columbia and Rodinia supercontinents. The craton is intruded by numerous regional-scale mafic dyke swarms of which only a few have robustly constrained emplacement ages. Through this study, the LIP record of the Dharwar craton has been improved by U-Pb geochronology of 18 dykes, which together comprise seven generations of Paleoproterozoic dyke swarms with emplacement ages within the 2.37-1.79 Ga age interval. From oldest to youngest, the new ages (integrated with U-Pb ages previously reported for the Hampi swarm) define the following eight swarms with their currently recommended names: NE-SW to ESE-WNW trending ca. 2.37 Ga Bangalore-Karimnagar swarm. N-S to NNE-SSW trending ca. 2.25 Ga Ippaguda-Dhiburahalli swarm. N-S to NNW-SSE trending ca. 2.22 Ga Kandlamadugu swarm. NW-SE to WNW-ESE trending ca. 2.21 Ga Anantapur-Kunigal swarm. NW-SE to WNW-ESE trending ca. 2.18 Ga Mahbubnagar-Dandeli swarm. N-S, NW-SE, and ENE-WSW trending ca. 2.08 Ga Devarabanda swarm. E-W trending 1.88-1.89 Ga Hampi swarm. NW-SE ca. 1.79 Ga Pebbair swarm. Comparison of the arcuate trends of some swarms along with an apparent oroclinal bend of ancient geological features, such as regional Dharwar greenstone belts and the late Archean (ca. 2.5 Ga) Closepet Granite batholith, have led to the hypothesis that the northern Dharwar block has rotated relative to the southern block. By restoring a 30° counter clockwise rotation of the northern Dharwar block relative to the southern block, we show that pre-2.08 Ga arcuate and fanning dyke swarms consistently become approximately linear. Two possible tectonic models for this apparent bending, and concomitant dyke rotations, are discussed. Regardless of which deformation mechanisms applies, these findings reinforce previous suggestions that the radial patterns of the giant ca. 2.37 Ga Bangalore-Karimnagar dyke swarm, and probably also the ca. 2.21 Ga Anantapur-Kunigal swarm, may not be primary features.
DS201908-1793
2019
Jayananda, M.Mohanty, N., Singh, S.P., Satyanarayanan, M., Jayananda, M., Korakoppa, M.M., Hiloidari, S.Chromianspinel compositions from Madawara ultramafics, Bundelkhand craton: implications on petrogenesis and tectonic evolution of the southern part of the Bundelkhand craton, central India.Geological Journal, Vol. 54, 4, pp. 2099-2123.Indiacraton

Abstract: Madawara ultramafic complex (MUC) in the southern part of Bundelkhand Craton, Central India comprises peridotite, olivine pyroxenite, pyroxenite, gabbro, and diorite. Coarse?grained olivine, clinopyroxene (Cpx), amphibole (Amp), Al?chromite, Fe?chromite, and magnetite with rare orthopyroxene (Opx) are common minerals in peridotite. Chromites are usually coarse?grained euhedral found as disseminated crystals in the olivine matrix showing both homogeneous and zoned texture. Al?chromite, primarily characterizes Cr?spinels and its subsequent fluid activity and alteration can result in the formation of Fe?chromite, chrome magnetite, and magnetite. Mineral chemistry data suggest that Al?chromite is characterized by moderately high Cr2O3 (38.16-51.52 wt.%) and Fe2O3 (3.22-14.51 wt.%) and low Al2O3 (10.63-21.87 wt.%), MgO (1.71-4.92 wt.%), and TiO2 (0.22-0.67 wt.%), whereas the homogeneous Fe?chromite type is characterized by high Fe2O3 (25.54-47.60 wt.%), moderately low Cr2O3 (19.56-37.90 wt.%), and very low Al2O3 (0.06-1.53 wt.%). Subsequent alteration of Al?chromite and Fe?chromite leads to formation of Cr?magnetite and magnetite. The Cr# of Al?chromite varies from 55.12 to 76.48 and ?Fe3+# from 8 to 19, whereas the ferrian chromite has high Cr# varying from 94.27 to 99.53 while its ?Fe3+# varies from 38 to 70. As a whole, the primary Al?chromite shows low Al2O3, TiO2 contents, and high Fe#, Cr# values. Olivines have forsterite ranging from 75.96% to 77.59%. The bulk?rock geochemistry shows continental arc geochemical affinities indicated by the high concentration of large?ion lithophile elements and U, Th relative to the low concentration of high?field strength elements. These petrological and mineralogical as well as primary Al?chromite compositions plotted in different discrimination diagrams suggest an arc environment that is similar to Alaskan?type intrusion.
DS201112-0269
2010
Jayaprakash, C.Dinesh, A.C., Maran, N., Shareef, N.M., Chandrasekaraiah, K.C., Jayaprakash, C.Observations on the reported incidence of micro-diamonds in the beach sands of the Kanyakumari Coast, Tamil Nadu.Journal of the Geological Society of India, Vol. 76, 6, pp. 587-588.IndiaAlluvials
DS201112-0270
2010
Jayaprakash, C.Dinesh, A.C., Maran, N., Shareef, N.M., Chandrasekaraih, K.C., Jayaprakash, C.Observations on the reported incidence of micro-diamonds in the beach sands of the Kanyakumari coast, Tamil Nadu.Journal of the Geological Society of India, Vol. 76, pp. 587-588.India, Tamil NaduMicrodiamonds
DS1950-0039
1950
Jayaraman, A.Raman, C.V., Jayaraman, A.The Luminescence of Diamond and its Relation to Crystal Structure.Indian Academy of Science Proceedings, Vol. 32, SECT. A, No. 2IndiaCrystallography
DS200512-1262
2005
J-BZheng, Y-F., Zhou, J-B, Wu, Y-B., Xie, Z.Low grade metamorphic rocks in the Dabie Sulu orogenic belt: a passive margin accretionary wedge deformed during continent subduction.International Geology Review, Vol. 47, 7, pp. 851-871.Asia, ChinaSubduction
DS1999-0733
1999
J-CTelmat, H., Mareschal, J-C, Gariepy, C.The gravity field over Ungava Bay region from satellite altimitry and newland based data: implications geologyCanadian Journal of Earth Sciences, Vol. 36, No. 1, Jan. pp. 75-89.Quebec, Labrador, UngavaGeophysics - gravity
DS201112-0480
2011
JCKonlineJCKonlineUpdate on the De Beers class action settlement.JCKOnline.com, Sept. 9, 2p.United StatesNews item - De Beers
DS2002-0771
2002
Jdypvik, H.Jdypvik, H., Nilsen, O.Rift valley sedimentation and diagenesis, Tanzanian examples - a reviewGeological Society of South Africa, Vol. 105, No. 2, pp. 93-106.TanzaniaStratigraphy - not specific to diamonds
DS2001-0649
2001
Jean, A.Lacroix, S., Doucet, P., Jean, A.Diamond and nickel potential of northern Quebec attracts attentionProspectors and Developers Association of Canada (PDAC) Exploration and development Highlights, pp. 10-11.Quebec, Ungava, LabradorKimberlites, Exploration - discoveries
DS201212-0646
2012
Jean, M.M.Shervais, J.W., Jean, M.M.Inside the subduction factory: modelling fluid mobile element enrichment in the mantle wedge above a subduction zone.Geochimica et Cosmochimica Acta, in press availableMantleSubduction
DS201212-0647
2012
Jean, M.M.Shervais, J.W., Jean, M.M.Inside the subduction factory: modeling fluid mobile element enrichment in the mantle wedge above a subduction zone.Geochimica et Cosmochimica Acta, Vol. 95, Oct. 15, pp. 270-285.MantleSubduction
DS201610-1874
2016
Jean, M.M.Jean, M.M., Taylor, L.A., Howarth, G.H., Peslier, A.H., Fedele, L., Bodnar, R.J., Guan, Y., Doucet, L.S., Ionov, D.A., Logvinova, A.M., Golovin, A.V., Sobolev, N.V.Olivine inclusions in Siberian diamonds and mantle xenoliths: contrasting water and trace -element contents.Lithos, in press available 11p.Russia, SiberiaDiamond inclusions
DS1994-1307
1994
Jeanhoz, R.O'Neill, B., Jeanhoz, R.MgSiO3 FeSiO3 Al2O3 in the earth's lower mantle:perovskite and garnet at1200 km depth.Journal of Geophysical Research, Vol. 99, No. B 10, Oct. 10, pp. 19, 901-916.MantlePerovskite, Petrology
DS1986-0405
1986
Jeanloz, R.Jeanloz, R., Morris, S.Temperature distribution in the crust and mantle. (Review)Annual Review Earth Sciences, Vol. 14, pp. 377-415GlobalThermobarometry, Geobarometry
DS1986-0450
1986
Jeanloz, R.Knittle, E., Jeanloz, R., Smith, G.L.Thermal expansion of silicate perovskite and stratification oftheearth's mantleNature, Vol. 319, Jan. 16, pp. 214-216GlobalMantle
DS1989-0804
1989
Jeanloz, R.Knittle, E., Jeanloz, R.Melting curve of (MgFe) SiO3 perovskite to 96 GPA:evidence for a structural transition in lower mantlemeltsGeophysical Research Letters, Vol. 14, No. 5, May pp. 421-424GlobalMantle, Mineral chemistry
DS1990-1024
1990
Jeanloz, R.Meade, C., Jeanloz, R.The strength of mantle silicates at high pressures and room temperature:implications for the viscosity of the mantleNature, Vol. 348, No. 6301, December 6, pp. 533-535GlobalMantle, Silicates
DS1990-1137
1990
Jeanloz, R.O'Neill, B., Jeanloz, R.Experimental petrology of a natural peridotite at lower mantle conditionsV.m. Goldschmidt Conference Held May 2-4, 1990, Program And Abstract, p. 71. Abstract onlyGlobalMantle, Experimental petrology
DS1990-1600
1990
Jeanloz, R.Xiaoyuan Li, Jeanloz, R.Laboratory studies of the electrical conductivity of silicate perovskites at high pressures and temperaturesJournal of Geophysical Research, Vol. 95, B4, April 10, pp. 5067-5078GlobalExperimental petrology, Perovskites
DS1991-0788
1991
Jeanloz, R.Jeanloz, R., Hazen, R.M.Finite strain analysis of relative compresibilities: application to the high pressure wadsleite phase.American Mineralogist, Vol. 76, pp. 1765-8.MantlePetrology - ultra high pressure (UHP)
DS1991-0891
1991
Jeanloz, R.Knittle, E., Jeanloz, R.The high pressure phase diagram of FeO.94O: a possible constituent of theearth's coreJournal of Geophysical Research, Vol. 96, No. B 10, September 10, pp. 16, 169-16, 180GlobalCore-mantle boundary, Geophysics -seismics
DS1991-0892
1991
Jeanloz, R.Knittle, E., Jeanloz, R.Earth's core-mantle boundary: results of experiments at high pressures andtemperaturesScience, Vol. 251, March 22, pp. 1438-1443GlobalMantle, Core boundary -experimental petrology
DS1991-1900
1991
Jeanloz, R.Xiaoyuan Li, Jeanloz, R.Phases and electrical conductivity of a hydrous silicate assemblage at lower mantle conditionsNature, Vol. 350, No. 6316, March 28, pp. 332-334GlobalSilicates -experimental, Mantle
DS1993-0741
1993
Jeanloz, R.Jeanloz, R.The mantle in sharper focusNature, Vol. 365, No. 6442, September 9, p. 110MantleGeophysics -seismics, Seismology
DS1993-0742
1993
Jeanloz, R.Jeanloz, R., Lay, T.The core-mantle boundaryScientific American, May pp. 48-55MantleOverview of structure of earth, Tectonics, Core
DS1993-1568
1993
Jeanloz, R.Takahashi, E., Jeanloz, R., Rubie, D.Evolution of the earth and planetsAmerican Geophysical Union IUGG Volume, Vol. 14, 159p. approx. $ 30.00GlobalBook -table of contents, ad, Planet -evolution
DS1996-0841
1996
Jeanloz, R.Li, X., Manga, M., Jeanloz, R.Temperature distribution in the laser heated diamond cell with externalheating, and implications perovskiteGeophysical Research Letters, Vol. 23, No. 25, Dec. 15, pp. 3775-3778.GlobalPerovskite
DS1997-0724
1997
Jeanloz, R.Manga, M., Jeanloz, R.Thermal conductivity of corundum and periclase and implications for the lower mantle.Journal of Geophysical Research, Vol. 102, No. 2, Feb. 10, pp. 2799-3008.MantleGeothermometry
DS1998-0691
1998
Jeanloz, R.Jeanloz, R., Williams, Q.The core-mantle boundary region #2Reviews in Mineralogy, Vol. 37, pp. 241-260.MantleGeophysics, Geodynamics - boundary
DS2000-0306
2000
Jeanloz, R.Funamori, N., Jeanloz, R., Fujino, K.Mineral assemblages of basalt in the lower mantleJournal of Geophysical Research, Vol.105, No.11, Nov.10, pp.26037-MantleLithosphere - mineral chemistry
DS2000-0313
2000
Jeanloz, R.Garnero, E.J., Jeanloz, R.Fuzzy patches on the earth's core mantle boundary?Geophysical Research Letters, Vol. 27, No. 17, Sept. 1, pp. 2777-80.MantleBoundary
DS2003-1217
2003
Jeanloz, R.Scandolo, S., Jeanloz, R.The centers of planets. In laboratories and computers, shocked and squeezed matterAmerican Scientist, Vol. 91, Nov-Dec. pp. 516-525.MantleDiamond genesis, metallic hydrogen, shock waves, sky, i
DS200412-1103
2004
Jeanloz, R.Lee, K.K., O'Neill, B., Panero, W.R., Shim, S.H., Benedetti, L.R., Jeanloz, R.Equations of state of the high pressure phases of a natural peridotite and implications for the Earth's lower mantle.Earth and Planetary Science Letters, Vol. 223, 3-4, pp. 381-393.MantlePeridotite, magnesiowustite
DS200412-1739
2003
Jeanloz, R.Scandolo, S., Jeanloz, R.The centers of planets. In laboratories and computers, shocked and squeezed matter turns metallic, coughs up diamonds and revealAmerican Scientist, Vol. 91, Nov-Dec. pp. 516-525.MantleDiamond genesis, metallic hydrogen, shock waves, sky, i
DS200612-0257
2006
Jeanloz, R.Clar, S.M., Speciale, S., Jeanloz, R., Kunz, M., Caldwell, W.A., Walter, M., Walker, D.Using advanced accelerators to understand the lower mantle and beyond.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 104, abstract only.MantleGeochemistry
DS1989-0710
1989
Jebrak, M.Jebrak, M.rare earth elements (REE) geochemistry in river sediments of the Greenville province (WesternQuebec)Xiii International Geochemical Exploration Symposium, Rio 89 Brazilian Geochemical, pp. 220-222. AbstractQuebecrare earth elements (REE)., Geochemistry
DS1996-0994
1996
Jebrak, M.Morin, D., Marquis, R., Jebrak, M.Un diatreme phreatomagmatique montregien dans les Appalaches du QuebecCanadian Journal of Earth Sciences, Vol. 33, No. 5, May pp. 649-655.QuebecGeophysics -magnetics, breccia, Basanite
DS1997-0555
1997
Jebrak, M.Jebrak, M.Hydrothermal breccias in vein type ore deposits: a review of mechanisms, morphology and size distributionOre Geol. Rev, Vol. 12, pp. 111-134GlobalBreccias - review, Tectonics, fluid assisted, reduction expansion, fractur
DS201312-0623
2013
Jebrak, M.Nadeau, O., Stevenson, R., Jebrak, M.Petrosomatic evolution of Montveil alkaline system and rare earth carbonatites, Abitibi, Canada.Goldschmidt 2013, AbstractCanada, QuebecCarbonatite
DS201412-0561
2014
Jebrak, M.Matton, G., Jebrak, M.The "eye of Africa" Richat dome, Mauritania: an isolated Cretaceous alkaline-hydrothermal complex.Journal of African Earth Sciences, Vol. 97, pp. 109-124.Africa, MauritaniaAlkalic
DS201412-0610
2014
Jebrak, M.Nadeau, O., Stevenson, R., Jebrak, M.The geology, petrology and geochemistry of the Montviel alkaline-carbonatite hosted lanthanide-Nb ore deposit, Abitibi, Canada.GAC-MAC Annual Meeting May, abstract 1p.Canada, QuebecCarbonatite
DS201502-0084
2015
Jebrak, M.Nadeau, O., Cayer, A., Pelletier, M., Stevenson, R., Jebrak, M.The Paleoproterozoic Montviel carbonatite hosted REE-Nb deposit, Abitibi, Canada: Geology, Mineralogy, Geochemistry and Genesis.Ore Geology Reviews, Vol. 67, pp. 314-335.Canada, QuebecCarbonatite
DS201511-1865
2015
Jebrak, M.Nadeau, O., Stevenson, R., Jebrak, M.Evolution of Montviel alkaline-carbonatite complex by coupled fractional crystallization, fluid mixing and metasomatism. Pts. 1 and 2.Ore Geology Reviews, Vol. 72, pp. 1143-1162.Canada, QuebecCarbonatite

Abstract: Magmatic volatiles are critically important in the petrogenesis of igneous rocks but their inherent transience hampers the identification of their role in magmatic and mineralization processes. We present evidence that magmatic volatiles played a critical role in the formation of the 1894 Ma Paleoproterozoic Montviel alkaline-carbonatite complex, Canada, and the related carbonatite-hosted REE-Nb deposit. Field and drill core relationships indicate that lithological units of the complex were emplaced in the following order: clinopyroxenites, melteigites, ijolites, melanosyenites, leucosyenites, granites, lamprophyric silicocarbonatites, rare magnesiocarbonatites, calciocarbonatites, ferrocarbonatites, late mixed carbonatites, kimberlitic silicocarbonatites and polygenic breccias. Magmatic minerals within these units were systematically metasomatized. In undersaturated silicate rocks, augite recrystallized to aegirine–augite and aegirine, plagioclase recrystallized to albite, and nepheline recrystallized with analcime, cancrinite and albite. Primary biotite was replaced by secondary, REE-rich metasomatic biotite, particularly along fractures and alteration pockets. In carbonatites, liquidus phases consisted of calcite and dolomite and were recrystallized to ferroan dolomite, ankerite, siderite, barytocalcite, witherite and strontianite, which are intimately related to the REE-bearing carbonates and fluorocarbonates. Biotite is common to all lithologies, ranges in REE concentrations from 1.5 to 230 ppm and yielded subsolidus crystallization temperatures ranging from 770 °C to 370 °C. Sm-Nd isotope analyses from biotite and aegirine-augite yield a range of ?Nd values (+ 3.4 to ? 3.0) that suggests mixing of fluids from three sources during the crystallization of the Montviel magmas. The clinopyroxenites to melteigite, ijolites and melanosyenites crystallized augite and biotite with initial ?Nd value ? 3.4 and these minerals were metasomatized by a 1st fluid, lowering their ?Nd to values comprised between 0.8 and 3.4. Silicocarbonatites and carbonatites subsequently crystallized aegirine-augite and biotite with initial ?Nd value ? 2.6 and a 2nd fluid metasomatized the minerals to lower ? values. Both the 1st and the 2nd fluids eventually mixed with a 3rd recrystallizing aegirine-augite and biotite and lower their ?Nd values down to ? 3.0. The results presented herein suggest that the mantle magmas evolved through 4 distinct mantle pulses by fractional crystallization, mixing of depleted mantle fluids with crustal fluids, and metasomatism. Some of the silicate rocks also show evidence of assimilation of wall rock as part of their petrogenetic evolution. During the last stages of its evolution in carbonatites, the fluid source transited from the depleted mantle to the crust and we speculate that this resulted in a violent explosive eruption creating the diatreme-shaped, HREE-rich polygenic breccia.
DS201711-2518
2017
Jebrak, M.Jebrak, M., Montel, J-M.Educating the resource geologist of the future: between observation and imagination.Elements, Vol. 13, pp. 331-336.Globalresources

Abstract: Training geologists for a career in the mining industry has changed over the years. It has become at the same time more specialized and with a broader approach. The modern resource geologist needs to understand new styles of ore deposits, the impact of energy transition on the types of deposits and to implement mining processes, the increasing number of mining regulations, and the shift toward educating populations in countries that are new to mining. Based on observation and imagination, rooted in fundamental science, the education of a resource geologist has been transformed by the digital revolution and the integration of the principles of sustainable development. Training future resource geologists means changing the role of teachers to better develop the imaginations of their students and to increasing what students know about the social impact of mining.
DS201801-0040
2018
Jebrak, M.Nadeau, O., Stevenson, R., Jebrak, M.Interaction of mantle magmas and fluids with crustal fluids at the 1894 Ma Montviel alkaline carbonatite complex, Canada: insights from metasomatic and hydrothermal carbonates.Lithos, Vol. 296-299, pp. 563-579.Canada, Quebeccarbonatite - Montviel

Abstract: Alkaline and carbonatite rocks are relatively rare but offer the opportunity to study the contribution of fluids in the genesis of mantle and crustal rocks because they are commonly affected by metasomatism. Carbonate minerals represent versatile archives of mantle and crustal magmatic-hydrothermal processes because they can have magmatic, metasomatic or hydrothermal origins and because they host the trace elements, stable and radiogenic isotopes required to unravel their petrogenesis. Previous studies have shown that the 1894 Ma Montviel alkaline?carbonatite complex was emplaced through four injections of volatile-saturated, mantle magmas which evolved through fractional crystallization, mixing of mantle and crustal fluids and metasomatism. Trace element analyses and ?18O, ?13C, 87Sr/86Sr and 143Nd/144Nd isotope compositions of metasomatic and hydrothermal carbonates further support that each magma injection was accompanied by a volatile phase. Variations in trace element concentrations suggest that the carbonatite might have exsolved from a metasomatized mantle or hybrid silicate?carbonatite magma, and that the fluid composition evolved towards higher REE and lower HFSE with increasing degree of segregation of the carbonatite magma and the silicate source. A strong correlation between the C-O-Sr isotopic systems show that mantle fluids mixed with crustal fluids, increasing the 87Sr/86Sr from mantle to crustal values, and driving the C and O isotopic ratios towards respectively lighter and heavier values. The Sm/Nd isotopic system was weakly coupled with the other isotopic systems as depleted mantle fluids mixed with crustal fluids and metasomatized the crystallizing magmas, thereby redistributing the REE and affecting their Sm/Nd ratios. The Nd isotopes suggest that the mixed mantle/crustal fluids redistributed the rare earth elements, producing ultra-depleted (?Nd = + 10), normally depleted (?Nd = + 4) and slightly enriched (?Nd = ? 2) isotopic compositions.
DS202109-1469
2021
Jedemann, A.Good, D.J., Hollings, P., Dunning, G., Epstein, R., McBride, J., Jedemann, A., Magnus, S., Bohav, T., Shore, G.A new model for the Coldwell Complex and associated dykes of the Midcontinent Rift, Canada.Journal of Petrology, Vol. 62, 7, 10.1093/petrology/ega036Canadadeposit - Coldwell

Abstract: Mafic intrusions on the NE shoulder of the Midcontinent Rift (Keweenawan LIP), including Cu-PGE mineralized gabbros within the Coldwell Complex (CC), and rift parallel or radial dykes outside the CC are correlated based on characteristic trace element patterns. In the Coldwell Complex, mafic rocks are subdivided into four groups: (1) early metabasalt; (2) Marathon Series; (3) Layered Series; (4) Geordie-Wolfcamp Series. The Marathon Series are correlated with the rift radial Abitibi dykes (1140?Ma), and the Geordie-Wolfcamp Series with the rift parallel Pukaskwa and Copper Island dykes. U-Pb ages determined for five gabbros from the Layered and Marathon Series are between 1107•7 and 1106•0?Ma. Radiogenic isotope ratios show near chondritic (CHUR) ?Nd(1106?Ma) and 87Sr/86Sri values that range from -0•38 to +1•13 and 0•702537 to 0•703944, respectively. Distinctive geochemical properties of the Marathon Series and Abitibi dykes, such as Ba/La (14-37), Th/Nb (0•06-0•12), La/Sm (3•8-7•7), Sr/Nd (21-96) and Zr/Sm (9-19), are very different from those of the Geordie-Wolfcamp Series and a subset of Copper Island and Pukaskwa dykes with Ba/La (8•7-11), Th/Nb (0•12-0•13), La/Sm (6•7-7•9), Sr/Nd (5-7•8) and Zr/Sm (18-24). Each unit exhibits covariation between incompatible element ratios such as Zr/Sm and Nb/La or Gd/Yb, Sr/Nd and Ba/La, and Nb/Y and Zr/Y, which are consistent with mixing relationship between two or more mantle domains. These characteristics are unlike those of intrusions on the NW shoulder of the MCR, but resemble those of mafic rocks occurring in the East Kenya Rift. The results imply that an unusual and long-lived mantle source was present in the NE MCR for at least 34?Myr (spanning the 1140?Ma Abitibi dykes and the 1106?Ma Marathon series) and indicate potential for Cu-PGE mineralization in an area much larger than was previously recognized.
DS201810-2311
2018
Jedlicka, R.Faryad, S.W., Jedlicka, R., Hauzenberger, C., Racek, M.High pressure crystallization vs. recrystallization origin of garnet pyroxenite-eclogite within subduction related lithologies. Bohemian MassifMineralogy and Petrology, Vol. 112, 5, pp. 603-616.Europe, Austriasubduction

Abstract: Mafic layers displaying transition between clinopyroxenite and eclogite within peridotite from felsic granulite in the Bohemian Massif (Lower Austria) have been investigated. The mafic-ultramafic bodies shared a common granulite facies metamorphism with its hosting felsic rocks, but they still preserve evidence of eclogite facies metamorphism. The selected mafic layer for this study is represented by garnet with omphacite in the core of coarse-grained clinopyroxene, while fine-grained clinopyroxene in the matrix is diopside. In addition, garnet contains inclusions of omphacite, alkali feldspars, hydrous and other phases with halogens and/or CO2. Textural relations along with compositional zoning in garnet from the clinopyroxenite-eclogite layers favour solid-state recrystallization of the precursor minerals in the inclusions and formation of garnet and omphacite during subduction. Textures and major and trace element distribution in garnet indicate two stages of garnet growth that record eclogite facies and subsequent granulite facies overprint. The possible model explaining the textural and compositional changes of minerals is that the granulite facies overprint occurred after formation and exhumation of the eclogite facies rocks.
DS1950-0396
1958
Jedwab, J.Jedwab, J.Prospection Geochimique de Kimberlit et Diamantifiere au Congo Belge.Geological Society BELGE Annual Bulletin., Vol. 67, No. 3, PP. 404-418.Democratic Republic of Congo, Central AfricaGeochemistry, Prospecting, Kimberlite, Diamond
DS1950-0397
1958
Jedwab, J.Jedwab, J.Looking for Kimberlitic Diamond Deposits by Geochemical Prospection.Symposium On Geology And Mineral Resources of Madhya Pradesh, Vol. 1, No. 3, PP. 68-71.India, Madhya PradeshProspecting, Geochemistry
DS202008-1403
2020
Jeffay, J.Jeffay, J.Size still matters. History of Cullinan diamond.Idexonline Memo , July 2, 2p.Africa, South Africadeposit - Premier
DS202008-1404
2020
Jeffay, J.Jeffay, J.Daytrip Mom finds 2.23 carat brown diamond at "Dig your own" mine.Idexonline Memo , June 30, 1p.United States, Arkansasdeposit - Crater of Diamonds
DS200412-0518
2004
Jeffcoate, A.Elliott, T., Jeffcoate, A., Bouman, C.The terrestrial Li isotope cycle: light weight constraints on mantle convection.Earth and Planetary Science Letters, Vol. 220, 3-4, pp. 231-245.MantleGeochronology
DS200612-0372
2006
Jeffcoate, A.Elliott, T., Jeffcoate, A., Kaseman, S.Li isotopic evidence for subduction induced mantle heterogeneity.Geochimica et Cosmochimica Acta, Vol. 70, 18, 1, p. 159, abstract only.MantleSubduction
DS200612-0373
2006
Jeffcoate, A.Elliott, T., Thomas, A., Jeffcoate, A., Niu, Y.Lithium isotope evidence for subduction enriched mantle in the source of mid-ocean ridge basalts.Nature, Vol. 443, Oct. 5, pp. 565-568.MantleRecyling, subduction
DS201708-1682
2017
Jeffcoate. A.Jeffcoate. A.3-D geological model of the BK16 kimberlite pipe located within the Orapa kimberlite field (OKF) in Botswana.11th. International Kimberlite Conference, PosterAfrica, Botswanadeposit - BK-16
DS200812-0519
2008
Jefferis, K.Jefferis, K.Botswana: economic overview. Presentation by Econsult group.Botswana Resource Conference held July 23-24., ppt presentation 24 slidesAfrica, BotswanaOverview
DS1989-0711
1989
Jefferson, C.W.Jefferson, C.W., Parrish, R.R.Late Proterozoic stratigraphy, uranium-lead (U-Pb) (U-Pb) zircon ages and rift Mackenzie Mountains, northwesternCanadaCanadian Journal of Earth Sciences, Vol. 26, No. 9, September pp. 1784-1801Northwest TerritoriesTectonics, Geochronology
DS1991-1297
1991
Jefferson, C.W.Park, J.K., Jefferson, C.W.Magnetic and tectonic history of the Late Proterozoic Upper Little Dal and Coates Lake Groups of northwestern CanadaPrecambrian Research, Vol. 52, No. 1/2, pp. 1-35Northwest TerritoriesTectonics, Paleomagnetics, Mackenzie Mountains
DS1992-0256
1992
Jefferson, C.W.Chung, C.F., Jefferson, C.W., Singer, D.A.A quantitative link among mineral deposit modelling, geoscience mapping and exploration resource assessmentEconomic Geology, Vol. 87, No. 1, Jan-Feb. pp. 194-197GlobalMineral exploration, ore reserves, Mineral deposit modeling
DS1994-0578
1994
Jefferson, C.W.Garson, D.F., Jefferson, C.W., Kerwill, J.A., et al.Mineral potential map of the northern Slave Province NTS 76, 86, a data-driven spatial modelling prototype for the mineral resources map of the Northwest Territories.Geological Survey of Canada Open Forum January 17-19th. Abstracts only, p. 17.Northwest TerritoriesMap, GIS
DS201112-0786
2011
Jefferson, C.W.Peterson, T.D., Scott, J.M.J., Jefferson, C.W.Uranium rich bostonite carbonatite dykes in Nunavut: recent observations. Deep Rose Lake area - minetteGeological Survey of Canada, Current Research 2011-11, 12p.Canada, NunavutCarbonatite
DS201608-1446
2016
Jefferson, C.W.Tschirhart, V., Jefferson, C.W., Morris, W.A.Basement geology beneath the northeast The lon Basin, Nunavut: insights from integrating new gravity, magnetic and geological data.Geophysical Prospecting, in press available Aug 8Canada, NunavutGeophysics

Abstract: Current models for unconformity-associated uranium deposits predict fluid flow and ore deposition along reactivated faults in >1.76 Ga basement beneath Mesoproterozoic siliciclastic basins. In frontier regions such as the Thelon Basin in the Kivalliq region of Nunavut, little is known about the sub-basin distribution of units and structures, making exploration targeting very tenuous. We constructed a geological map of the basement beneath the unconformity by extrapolating exposed features into the subsurface. The new map is constrained by detailed geological, geophysical, and rock property observations of outcrops adjacent to the basin and by aeromagnetic and gravity data over the geophysically transparent sedimentary basin. From rock property measurements, it is clear that the diverse magnetic and density characteristics of major rock packages provide quantitative three-dimensional constraints. Gravity profiles forward modelled in four cross sections define broad synforms of the Amer Belt and Archean volcanic rocks that are consistent with the structural style outside the basin. Major lithotectonic entities beneath the unconformity include: supracrustal rocks of the Archean Woodburn Lake group and Marjorie Hills meta sedimentary gneiss and associated mixed granitoid and amphibolitic gneiss; the Amer Mylonite Zone and inferred mafic intrusions oriented parallel and sub-parallel; other igneous intrusions of 2.6 Ga, 1.83 Ga, and 1.75 Ga vintage; and the <2.3 Ga to >1.84 Ga Amer Group. Four main brittle regional fault arrays (040°-060°, 075°-90°, 120°, and 150°) controlled development and preservation of the basin. The reactivated intersections of such faults along fertile basement units such as the Rumble assemblage, Marjorie Hills assemblage, Nueltin igneous rocks, and Pitz formation are the best targets for uranium exploration.
DS201703-0435
2017
Jefferson, C.W.Tschirhart, V., Jefferson, C.W., Morris, W.A.Basement geology beneath the northeast The lon Basin, Nunavut: insights from integrating new gravity, magnetic and geological data.Geophysical Prospecting, Vol. 65, 2, pp. 617-636.Canada, NunavutGeophysics - Thelon Basin

Abstract: Current models for unconformity-associated uranium deposits predict fluid flow and ore deposition along reactivated faults in >1.76 Ga basement beneath Mesoproterozoic siliciclastic basins. In frontier regions such as the Thelon Basin in the Kivalliq region of Nunavut, little is known about the sub-basin distribution of units and structures, making exploration targeting very tenuous. We constructed a geological map of the basement beneath the unconformity by extrapolating exposed features into the subsurface. The new map is constrained by detailed geological, geophysical, and rock property observations of outcrops adjacent to the basin and by aeromagnetic and gravity data over the geophysically transparent sedimentary basin. From rock property measurements, it is clear that the diverse magnetic and density characteristics of major rock packages provide quantitative three-dimensional constraints. Gravity profiles forward modelled in four cross sections define broad synforms of the Amer Belt and Archean volcanic rocks that are consistent with the structural style outside the basin. Major lithotectonic entities beneath the unconformity include: supracrustal rocks of the Archean Woodburn Lake group and Marjorie Hills meta sedimentary gneiss and associated mixed granitoid and amphibolitic gneiss; the Amer Mylonite Zone and inferred mafic intrusions oriented parallel and sub-parallel; other igneous intrusions of 2.6 Ga, 1.83 Ga, and 1.75 Ga vintage; and the <2.3 Ga to >1.84 Ga Amer Group. Four main brittle regional fault arrays (040°-060°, 075°-90°, 120°, and 150°) controlled development and preservation of the basin. The reactivated intersections of such faults along fertile basement units such as the Rumble assemblage, Marjorie Hills assemblage, Nueltin igneous rocks, and Pitz formation are the best targets for uranium exploration.
DS1993-0743
1993
Jefferson, C.W. ChandlerJefferson, C.W. Chandler, Hulbert, Smith, FitzhenryAssessment of mineral and energy resource potential in the Laughland Lake terrestrial area and Wag Marine areaGeological Survey of Canada (GSC) Open File, No. 2659, 60p.Northwest TerritoriesExploration
DS1960-0749
1966
Jefferson-Smith, T.Steinhart, J.S., Jefferson-Smith, T.The Earth Beneath the Continents. a Volume of Geophysical Studies.American GEOPHYSICAL MONOGRAPH, No. 10, 663P.GlobalMid-continent, Geophysics
DS201412-1015
2014
Jeffreis, T.E.Zaitsev, A.N., Williams, C.T., Jeffreis, T.E., Strekopytov, S., Moutte, J., Ivashchenkova, O.V., Spratt, J., Petrov, S.V., Wall, F., Seltmann, R., Borozdin, A.P.Rare earth elements in phoscorites and carbonatites of the Devonian Kola alkaline province, Russia: examples from Kovdor, Khibina, Vuoriyarvi and Turiy Mys complexes.Ore Geology Reviews, Vol. 64, pp. 204-225.Russia, Kola PeninsulaCarbonatite
DS1993-0166
1993
Jeffrey, C.Brooks, W.E., Orrism G.J., Wynn, G.J., Jeffrey, C.Carbonatite depositsUnited States Geological Survey (USGS) Bulletin, No. B2062, pp. 73-75.VenezuelaCarbonatite
DS201212-0122
2012
Jeffrey, C.Chambers, J.E., Wilkinson, P.B., Wardrop, D., Hameed, A., Hill, L., Jeffrey, C., Loke, Mledrum, Kuras, Cave, GunnBedrock detection beneath river terrace deposits using three dimensional electrical resistivity tomography.Geomorphology, Vol. 177-178, pp. 7-25.TechnologyTomography - not specific to diamonds
DS201312-0144
2013
Jeffrey, C.Chambers, J.E., Wilkinson, P.B., Wrdrop, D., Hameed, A., Hill, I., Jeffrey, C., Loke, M.H., Meldrum, P.I., Kuras, O., Cave, M., Gunn, D.A.Bedrock detection beneath river terrace deposits using three dimensional electrical resistivity tomography.Geomorphology, Vol. 177-178, pp. 17-25.GlobalGeochronology
DS1859-0011
1750
Jeffries, D.Jeffries, D.Treatise on DiamondsLondon:, GlobalGemology
DS2002-1499
2002
Jeffries, T.Sitnikova, M.A., Wall, F., Jeffries, T., Zaitsev, A.N.Ancylite group minerals in the Sallaniatvi carbonatites, Kola Peninsula, Russia18th. International Mineralogical Association Sept. 1-6, Edinburgh, abstract p.251-2.Russia, Kola PeninsulaCarbonatite - mineralogy
DS200512-1055
2005
Jeffries, T.Stoppa, F., Rosatelli, G., Wall, F., Jeffries, T.Geochemistry of carbonatite silicate pairs in nature: a case history from central Italy.Lithos, Advanced in press,Europe, ItalyKamafugite, foidite
DS200512-1056
2005
Jeffries, T.Stoppa, F., Rosatelli, G., Wall, F., Jeffries, T.Geochemistry of carbonatite - silicate pairs in nature: a case history from central Italy.Lithos, Advanced in press,Europe, ItalySan Venanzo kamafugite, carbonatite
DS200612-1382
2005
Jeffries, T.Stoppa, F., Rosatelli, G., Wall, F., Jeffries, T.Geochemistry of carbonatite silicate pairs in nature: a case history from Central Italy.Lithos, Vol. 85, 1-4, Nov-Dec. pp. 26-47.Europe, ItalyCarbonatite, geochemistry
DS200712-0253
2007
Jeffries, T.Dobosi, G., Wall, F., Jeffries, T.Trace element fractionation during exsolution of garnet from clinopyroxene in an eclogite xenolith from Obnazhennaya(Siberia).Plates, Plumes, and Paradigms, 1p. abstract p. A227.Russia, SiberiaObnazhennaya
DS200712-1129
2007
Jeffries, T.Wall, F., Niku-Paavola, V.N., Storey, C., Muller, A.,Jeffries, T.Xenotime from carbonatite dykes at Lofdal Namibia - an extension of carbonatite REE mineralization, first dating of xenotime overgrowths on zircon.LA-ICP-MS-U-PbFrontiers in Mineral Sciences 2007, Joint Meeting of Mineralogical societies Held June 26-28, Cambridge, Abstract Volume p. 89-90.Africa, NamibiaCarbonatite
DS200712-1130
2007
Jeffries, T.Wall, F., Niku-Paavola, V.N., Storey, C., Muller, A.,Jeffries, T.Xenotime from carbonatite dykes at Lofdal Namibia - an extension of carbonatite REE mineralization, first dating of xenotime overgrowths on zircon.LA-ICP-MS-U-PbFrontiers in Mineral Sciences 2007, Joint Meeting of Mineralogical societies Held June 26-28, Cambridge, Abstract Volume p. 89-90.Africa, NamibiaCarbonatite
DS200812-1227
2008
Jeffries, T.Wall, F., Niku-Paavola, V.N., Storey, C., Muller, A., Jeffries, T.Xenotime - (Y) from carbonatite dykes at Lofdal, Namibia: unusually low LREE:HREE ratio in carbonatite, and the first dating of xenotime overgrowths on zircon.Canadian Mineralogist, Vol. 46, 4, August pp.Africa, NamibiaCarbonatite
DS201012-0416
2010
Jeffries, T.Kurzura, A.V., Wall, F., Jeffries, T., Litvin, Yu.A.Partitioning of trace elements between garnet, clinopyroxene and diamond forming carbonate silicate melt at 7 GPa.International Mineralogical Association meeting August Budapest, abstract p. 573.TechnologyGeochemistry
DS201012-0420
2010
Jeffries, T.Kuzyura, A.V., Wall, F., Jeffries, T., Litvin, Y.U.A.Partitioning of trace elements between garnet, clinopyroxene and diamond forming carbonate-silicate melt at 7 GPa.Mineralogical Magazine, Vol. 74, 2, pp. 227-239.TechnologyDiamond genesis
DS201012-0826
2010
Jeffries, T.Wall, F., Rosatelli, G., Jeffries, T.Trace element partition coefficients for apatite, calcite and carbonatite melt at crustal pressures and temperatures.International Mineralogical Association meeting August Budapest, abstract p. 554.Europe, GermanyAlkalic
DS201112-0755
2011
Jeffries, T.Okoemova, V.Yu., Vasiliev, P.G., Kuzyura, A.V., Litvin, Yu.A., Wall, F., Jeffries, T.Experimental study of partition of rare elements between minerals and melts of diamond forming eclogite carbonatite and peridotite carbonatites systems.Goldschmidt Conference 2011, abstract p.1566.TechnologyHP
DS201412-0494
2014
Jeffries, T.Kuzyura, A.V., Litvin, Yu.A., Vasilev, P.G., Jeffries, T., Wall, F.Partitioning of rare elements between diamond forming melts and minerals of the peridotite-carbonatite system.Doklady Earth Sciences, Vol. 455, 2, pp. 419-424.TechnologyPhysicochemical experiments
DS201502-0071
2015
Jeffries, T.Kuzyura, A.V., Litvin, Yu.A., Jeffries, T.Interface partition coefficients of trace elements in carbonate-silicate parental media for diamonds and paragenetic inclusions ( experiments at 7.0-8.5 Gpa)Russian Geology and Geophysics, Vol. 56, 1-2, pp. 221-231.TechnologyDiamond inclusions
DS201805-0977
2018
Jeffries, T.Smith, M., Kynicky, J., Xu, C., Song, W., Spratt, J., Jeffries, T., Brtnicky, M., Kopriva, A., Cangelosi, D.The origin of secondary heavy rare earth element enrichment in carbonatites: constraints from the evolution of the Huanglongpu district, China.Lithos, Vol. 308-309, pp. 65-82.Chinacarbonatite

Abstract: The silico?carbonatite dykes of the Huanglongpu area, Lesser Qinling, China, are unusual in that they are quartz-bearing, Mo-mineralised and enriched in the heavy rare earth elements (HREE) relative to typical carbonatites. The textures of REE minerals indicate crystallisation of monazite-(Ce), bastnäsite-(Ce), parisite-(Ce) and aeschynite-(Ce) as magmatic phases. Burbankite was also potentially an early crystallising phase. Monazite-(Ce) was subsequently altered to produce a second generation of apatite, which was in turn replaced and overgrown by britholite-(Ce), accompanied by the formation of allanite-(Ce). Bastnäsite and parisite where replaced by synchysite-(Ce) and röntgenite-(Ce). Aeschynite-(Ce) was altered to uranopyrochlore and then pyrochlore with uraninite inclusions. The mineralogical evolution reflects the evolution from magmatic carbonatite, to more silica-rich conditions during early hydrothermal processes, to fully hydrothermal conditions accompanied by the formation of sulphate minerals. Each alteration stage resulted in the preferential leaching of the LREE and enrichment in the HREE. Mass balance considerations indicate hydrothermal fluids must have contributed HREE to the mineralisation. The evolution of the fluorcarbonate mineral assemblage requires an increase in aCa2+ and aCO32? in the metasomatic fluid (where a is activity), and breakdown of HREE-enriched calcite may have been the HREE source. Leaching in the presence of strong, LREE-selective ligands (Cl?) may account for the depletion in late stage minerals in the LREE, but cannot account for subsequent preferential HREE addition. Fluid inclusion data indicate the presence of sulphate-rich brines during alteration, and hence sulphate complexation may have been important for preferential HREE transport. Alongside HREE-enriched magmatic sources, and enrichment during magmatic processes, late stage alteration with non-LREE-selective ligands may be critical in forming HREE-enriched carbonatites.
DS1997-0556
1997
Jeffries, T.E.Jeffries, T.E., Longerich, H.P., et al.Mineral analysis using ablation microprobe inductively coupled plasma massspectrometry.Geoanalysis 97 abstract volume, June Vail, Colorado, p. 35.GreenlandCarbonatite, Igaliko dyke
DS200512-0756
2005
Jeffries, T.E.Munoz, M., Sagredo, J., De Ignacio, C., Fernandez-Suarez, J., Jeffries, T.E.New dat a ( U Pb K Ar ) on the geochronology of the alkaline carbonatitic association of Fuerteventura Canary Islands, Spain.Lithos, Advanced in press,Europe, Spain, Canary IslandsCarbonatite, geochronology
DS200612-0955
2005
Jeffries, T.E.Munoz, M., Agredo, J., De Ignacio, C., Fernandez-Suarez, J., Jeffries, T.E.New dat a ( U Pb K Ar) on the geochronology of the alkaline carbonatitic association of Fuerteventura, Canary Islands, Spain.Lithos, Vol. 85, 1-4, Nov-Dec. pp. 140-153.Europe, SpainCarbonatite, Geochronology
DS200812-1228
2008
Jeffries, T.E.Wall, F., Rosatelli, G., Bailey, D.K., Jeffries, T.E., Kearne, S., Munoz, M.Comparison of calcite compositions from extrusive carbonatites at Kaisterstuhl, Germany and Calatrava, Spain: implications for mantle carbonate.9IKC.com, 3p. extended abstractEurope, Germany, SpainCarbonatite
DS201412-1017
2014
Jeffries, T.E.Zaitsev, A.N., Williams, C.T., Jeffries, T.E., Strekopytov, S., Moutte, J., Ivashchenkova, O.V., Spratt, J., Petrov, S.V., Wall, F., Seltmann, R., Borozdin, A.P.Rare earth elements in phoscorites and carbonatites of the Devonian Kola alkaline province, Russia: examples from Kovdor, Khibina, Vuoriyarvi and Turiy Mys complexes.Ore Geology Reviews, Vol. 61, pp. 204-225.Russia, Kola PeninsulaCarbonatite
DS201412-1019
2014
Jeffries, T.E.Zaitsev, A.N., Williams, C.T., Jeffries, T.E., Strekopytov, S., Moutte, J., Ivashchenkova, O.V., Spratt, J., Petrov, S.V., Wall, F., Seltmann, R., Borozdin, A.P.Rare earth elements in phoscorites and carbonatites of the Devonian Kola alkaline province, Russia: examples from Kovdor, Khibina, Vuoriyarvi and Turiy Mys complexes.Ore Geology Reviews, in press availableRussia, Kola PeninsulaCarbonatite
DS1980-0183
1980
Jegadessan, K.Jegadessan, K., Pundarikakshudu, T.Pilot Processing Plant for Exploration of DiamondsIndia Geological Survey Spec. Publishing, No. 4, PP. 602-606.India, WajrahkarurMining Engineering
DS2003-0650
2003
Jehlicka, J.Jehlicka, J., Svatos, A., Frank, O., Uhlik, F.Evidence for fullerenes in solid bitumen from pillow lavas of Proterozoic age fromGeochimica et Cosmochimica Acta, Vol. 67, 8, pp. 1495-1506.Czech RepublicFullerenes
DS200412-0909
2003
Jehlicka, J.Jehlicka, J., Svatos, A., Frank, O., Uhlik, F.Evidence for fullerenes in solid bitumen from pillow lavas of Proterozoic age from Mikov ( Bohemian Massif, Czech Republic).Geochimica et Cosmochimica Acta, Vol. 67, 8, pp. 1495-1506.Europe, Czech RepublicFullerenes
DS1995-1334
1995
Jekell, C.Nerem, R.S., Jekell, C., Kaula, W.M.Gravity field determinations and characteristic: retrospective andperspectiveJournal of Geophysical Research, Vol. 100, No. B8, Aug. 10, pp. 15, 053-74GlobalGeophysics -gravity, Review field determinations
DS2001-0188
2001
Jelenek, E.Christensen, N.I., Medaris, L.G.Jr., Jelenek, E.Depth variation of seismic anisotropy and petrology in central European lithosphere: tectonothermal synthesisJournal of Geophysical Research, Vol. 106, No. 1, Jan. 10, pp.645-64.EuropeLherzolites, Geothermometry
DS1995-1221
1995
Jelenik, E.Medaris, G., Jelenik, E., Misar, Z.Czech eclogites -terrane settings and implications for variscan tectonic evolution of the Bohemian Massif.European Journal of Mineralogy, Vol. 7, No. 1, Jan-Feb. pp. 7-28.GlobalEclogites, Terrane, tectonics
DS201504-0208
2015
Jelezko, F.McGuiness, L.P., Jelezko, F.Look but don't touch the metals.Science, Vol. 347, 6226, pp. 1073-1074 Mar. 6.TechnologyMetal conductivity, atomic defects in diamond
DS202003-0348
2020
Jelezko, F.Lee, C.W.Y., Cheng, J., Yium Y.C., Chan, K., Lau, D., Tang, W.C., Cheng, K.W,m Kong, T., Hui, T.K.C., Jelezko, F.Correlation between EPR spectra and coloration of natural diamonds.Diamond & Related Materials, Vol. 103, 13p. PdfGlobaldiamond colour

Abstract: White diamonds color grading is one of the basic diamond evaluations. The color value based on a scale that ranges from D to Z, with D being the more colorless and more valuable, among other qualifications. As the diamond grade moves on this scale, its color appears more yellow progressively. This yellowish color, present only in Type I diamonds, is mainly due to the nitrogen related defects such as N3 center and C-center. The current color grading system is based on a visual method, where gemologist compares the sample with a Master Color set. However, this method is very subjective. Several defects responsible for light absorption in diamond are carrying electron spin and appear in Electron Paramagnetic Resonance (EPR) spectrum. In this study, we developed a new EPR based technique for a quantitative measurement of N3 center and C-center in diamond through quantitative EPR spectroscopy. The correlation between EPR spectra and color grades of diamond was established.
DS1995-1222
1995
Jelinek, E.Medaris, G., Jelinek, E., Misar, Z.Czech eclogites: terrane settings and implications for Variscan tectonic evolution of the Bohemmian Massif.Eur. Journal of Mineralogy, No. 1, pp. 7-28.GlobalEclogites, Tectonics
DS1995-1224
1995
Jelinek, E.Medaris, L.G.Jr., Fournelle, J.H., Jelinek, E.Thermobarometry and reconstructed chemical composition pyroxene spinelsymplectites: Czech Neogene lavas.Proceedings of the Sixth International Kimberlite Conference Abstracts, pp. 371-373.GlobalGeobarometry, Symplectites
DS200912-0001
2009
Jelinek, E.Ackerman, L., Walker, R.J., Puchtel, I.S., Pitcher, L., Jelinek, E., Strnad, L.Effects of melt percolation on highly siderophile elements and Os isotopes in subcontinental lithospheric mantle: a study of upper mantle profile central EuropeGeochimica et Cosmochimica Acta, Vol. 73, 8, pp. 2400-2414.Europe, Czech RepublicGeochonology
DS201412-0426
2014
Jeljanin, B.Jeljanin, B.Coloured diamonds from the Argyle mine, Australia.Vancouver Kimberlite Cluster, April 30, 1p. AbstractTechnologyDeposit - Argyle
DS2001-0456
2001
JellicoeHarvey, S.E., Kjarsgaard, Jellicoe, KelleyHistory and current status of diamond exploration in SaskatchewanSaskatchewan Open House abstracts, Nov. p. 23.SaskatchewanHistory - brief
DS2002-0819
2002
Jellicoe, B.Kelley, L., Harvey, S., Jellicoe, B.Diamondiferous kimberlites of central SaskatchewanGac/mac Annual Meeting, Saskatoon, Abstract Volume, P.59., p.59.SaskatchewanGeochronology, stratigraphy, petrology, Deposit - Fort a la Corne
DS2002-0820
2002
Jellicoe, B.Kelley, L., Harvey, S., Jellicoe, B.Diamondiferous kimberlites of central SaskatchewanGac/mac Annual Meeting, Saskatoon, Abstract Volume, P.59., p.59.SaskatchewanGeochronology, stratigraphy, petrology, Deposit - Fort a la Corne
DS2003-0102
2003
Jellicoe, B.Berryman, A., Scott Smith, B., Jellicoe, B.Geology and diamond distribution of the 140/141 kimberlite, Fort a la Corne Central8th. International Kimberlite Conference Large Core Exhibit volume, 5p.SaskatchewanGeology - overview, Deposit - 140/141
DS200412-0140
2003
Jellicoe, B.Berryman, A., Scott Smith, B., Jellicoe, B.Geology and diamond distribution of the 140/141 kimberlite, Fort a la Corne Central saskatchewan, Canada.8th. International Kimberlite Conference Large Core Exhibit volume, 5p.Canada, SaskatchewanGeology - overview Deposit - 140/141
DS200912-0796
2009
Jellicoe, B.Verigeanu, D., Hetman, C.M., Jellicoe, B., Baumgartner, M.C.Preliminary geology, mineral chemistry and diamond results from the C29/30 Candle Lake volcanic complex, Saskatchewan, Canada.Lithos, In press - available formatted 12p.Canada, SaskatchewanDeposit - Candle Lake
DS1998-0692
1998
Jellicoe, B.C.Jellicoe, B.C., Robertshaw, P., Williamson, P. Murphy.Summary of exploration activities and results for the Fort a la Corne diamond project.Saskatchewan Report of Activities, miscellaneous Report, No. 98-4, pp. 144-57.SaskatchewanExploration - brief overview
DS1998-0693
1998
Jellicoe, B.C.Jellicoe, B.C., Robertshaw, P., Williamson, P., MurphySummary of exploration activities and results for Fort a la Corne diamond project, Saskatchewan.Saskatchewan Geological Survey Summary 1998, pp.SaskatchewanExploration
DS2000-0445
2000
Jellicoe, B.C.Jellicoe, B.C., Robertson, Billingsley, KjarsgaardSummary of investigation: the diamond potential of Saskatchewan, 2000. a study in progress.Saskatchewan Mineral Report, No. 2000, 4-2, pp. 223-5.SaskatchewanGeology - brief overview
DS2002-0772
2002
Jellicoe, B.C.Jellicoe, B.C.Exploration and evaluation of the Fort a la Corne diamond field, central Saskatchewan30th. Yellowknife Geoscience Forum, Abstracts Of Talks And Posters, Nov. 20-22, p. 31. abstractSaskatchewanBrief overview, grade and valuations
DS2002-0773
2002
Jellicoe, B.C.Jellicoe, B.C., Robertshaw, P., Williamson, P., Murphy, J.Exploration activities and results for the Fort a la Corne diamond projects, Saskatchewan.Canadian Institute of Mining and Metallurgy, Vol. 53, Industrial Minerals of Canada, pp. 327-44.SaskatchewanHistory - exploration
DS2002-1799
2002
Jellicoe, B.C.Zonnenwald, J.P., Jellicoe, B.C., Taylor, McNeilSedimentology and stratigraphy of Cretaceous Diamondiferous kimberlites, east central Saskatchewan.Gac/mac Annual Meeting, Saskatoon, Abstract Volume, P.132., p.132.SaskatchewanKimberlite - reworking, stratigraphy
DS2002-1800
2002
Jellicoe, B.C.Zonnenwald, J.P., Jellicoe, B.C., Taylor, McNeilSedimentology and stratigraphy of Cretaceous Diamondiferous kimberlites, east central Saskatchewan.Gac/mac Annual Meeting, Saskatoon, Abstract Volume, P.132., p.132.SaskatchewanKimberlite - reworking, stratigraphy
DS2003-0103
2003
Jellicoe, B.C.Berryman, A.K., Scott Smith, B.H., Jellicoe, B.C.Geology and distribution of the 140/141 kimberlite pipe, Fort a la Corne area, central8 Ikc Www.venuewest.com/8ikc/program.htm, Session 1, AbstractSaskatchewanGeology, economics
DS2003-0651
2003
Jellicoe, B.C.Jellicoe, B.C., Zonnenveld, J.P., Marcia, K.Discovery and evolution of exploration methods at the Fort a la Corne kimberlite fieldGeological Association of Canada Annual Meeting, Abstract onlySaskatchewanTechniques
DS200412-0141
2003
Jellicoe, B.C.Berryman, A.K., Scott Smith, B.H., Jellicoe, B.C.Geology and distribution of the 140/141 kimberlite pipe, Fort a la Corne area, central Saskatchewan, Canada.8 IKC Program, Session 1, AbstractCanada, SaskatchewanGeology, economics
DS200412-0910
2003
Jellicoe, B.C.Jellicoe, B.C., Zonnenveld, J.P., Marcia, K.Discovery and evolution of exploration methods at the Fort a la Corne kimberlite field, Saskatchewan.Geological Association of Canada Annual Meeting, Abstract onlyCanada, SaskatchewanTechniques
DS201112-0373
2011
Jellinek, A.Gleeson, T., Smith, L., Moosdorf, N., Hartmann, J., Durr, H.H., manning, A.H., Van Beek, P.H., Jellinek, A.Mapping permeability over the surface of the Earth.Geophysical Research Letters, Vol. 38, L02401MantleGeophysics
DS1999-0336
1999
Jellinek, A.M.Jellinek, A.M., Kerr, R.C., Griffiths, R.W.Mixing and compositional stratification produced by natural convection.1.experiments and their applicationJournal of Geophysical Research, Vol. 104, No. 4, Apr. 10, pp. 7183-7202.MantleEarth's core and mantle, Petrology - experimental
DS2002-0592
2002
Jellinek, A.M.Gonnermann, H.M., Manga, M., Jellinek, A.M.Dynamics and longevity of an initially stratified mantleGeophysical Research Letters, Vol. 29,10,May15,pp.33-MantleGeodynamics
DS2002-0774
2002
Jellinek, A.M.Jellinek, A.M., Lenardic, A., Manga, M.The influence of interior mantle temperature on the structure of plumes: heads for Venus, tails for Earth.Geophysical Research Letters, Vol. 29, 10, DOI 10.1029/2001GL014624MantleHot spots, plumes
DS2002-0775
2002
Jellinek, A.M.Jellinek, A.M., Manga, M.The influence of a chemical boundary layer on the fixity, spacing and life time of mantle plumes.Nature, Vol. 418, Aug. 15, pp. 760-763.MantleHotposts, Geophysics - seismics
DS2003-0652
2003
Jellinek, A.M.Jellinek, A.M., Gonnermann, H.M., Richards, M.A.Plume capture by divergent plate motions: implications for the distribution of hotspotsEarth and Planetary Science Letters, Vol. 205, 3-4, pp. 361-78.MantleGeothermometry, Core - mantle boundary
DS200412-0691
2004
Jellinek, A.M.Gonnermann, H.M., Jellinek, A.M., Richards, M.A., Manga, M.Modulation of mantle plumes and heat flow at the core mantle boundary by plate scale flow: results from laboratory experiments.Earth and Planetary Science Letters, Vol. 226, 1-2, pp. 53-67.MantleGeothermometry, boundary
DS200512-0476
2004
Jellinek, A.M.Jellinek, A.M., Manga, M.Links between long lived hot spots, mantle plumes, D' and plate tectonics.Reviews of Geophysics, Vol. 42, 3, RG3002MantleTectonics
DS200512-0618
2005
Jellinek, A.M.Lenardic, A., Moresi, L.N., Jellinek, A.M., Manga, M.Continental insulation, mantle cooling, and the surface area of oceans and continents.Earth and Planetary Science Letters, Vol. 234, 3-4, pp. 317-333.MantleGeothermometry
DS200712-0036
2007
Jellinek, A.M.Audet, P., Jellinek, A.M., Uno, H.Mechanical controls on the deformation of continents at convergent margins.Earth and Planetary Science Letters, Vol. 264, 1-2, pp. 151-166.MantleTectonics
DS200912-0433
2009
Jellinek, A.M.Lenardic, A., Jellinek, A.M.Tails of two plume types in one mantle.Geology, Vol. 37, 2, pp. 127-130.MantlePlume, hotspots
DS200912-0550
2009
Jellinek, A.M.O'Neill, C., Lenardic,A., Jellinek, A.M., Moresi, L.Influence of supercontinents on deep mantle flow.Gondwana Research, Vol. 15, 3-4, pp. 276-287.MantleMelting
DS201212-0110
2012
Jellinek, A.M.Carazzo, G., Jellinek, A.M.A new view of the dynamics, stability and longevity of volcanic clouds.Earth and Planetary Science Letters, Vol. 325-326, pp. 39-51.MantleVolcanism
DS201212-0303
2012
Jellinek, A.M.Hodge, K.F., Carazzo, G., Jellinek, A.M.Experimental constraints on the deformation and breakup of injected magma.Earth and Planetary Science Letters, Vol. 325-326, pp. 52-62.MantleMagmatism
DS201511-1845
2015
Jellinek, A.M.Jellinek, A.M., Jackson, M.G.Connections between bulk composition, geodynamics and habitability of Earth.Nature Geoscience, Vol. 8, pp. 587-593.MantleGeodynamics

Abstract: The bulk composition of the silicate part of Earth has long been linked to chondritic meteorites. Ordinary chondrites — the most abundant meteorite class — are thought to represent planetary building materials. However, a landmark discovery showed that the 142Nd/144Nd ratio of the accessible parts of the modern terrestrial mantle on Earth is greater than that of ordinary chondrites. If Earth was derived from these precursors, mass balance requires that a missing reservoir with 142Nd/144Nd lower than ordinary chondrites was isolated from the accessible mantle within 20 to 30 million years of accretion. This reservoir would host the equivalent of the modern continents' budget of radioactive heat-producing elements (uranium, thorium and potassium), yet has not been discovered. We argue that this reservoir could have been lost to space by ablation from early impactors. If so, Earth's radiogenic heat generation is between 18 and 45% lower than estimates based on a chondritic composition. Calculations of Earth's thermal history that incorporate such reduced radiogenic heating are consistent with a transition to the current plate tectonic mode in the past 2.5 billion years or so, a late onset of the dynamo and an evolving rate of volcanic outgassing consistent with Earth's long-term habitable climate. Reduced heat production compared with Venus and Mars could also explain aspects of the differences between the current climatic regimes of these planets and Earth.
DS201709-2013
2017
Jellinek, A.M.Karlstrom, L., Paterson, S.R., Jellinek, A.M.A reverse energy cascade for crustal magma transport.Nature Geoscience, Vol. 10, pp. 604-608.Mantlemagmatism

Abstract: Direct constraints on the ascent, storage and eruption of mantle melts come primarily from exhumed, long-frozen intrusions. These structures, relics of a dynamic magma transport network, encode how Earth’s crust grows and differentiates over time. Furthermore, they connect mantle melting to an evolving distribution of surface volcanism. Disentangling magma transport processes from the plutonic record is consequently a seminal but unsolved problem. Here we use field data analyses, scaling theory and numerical simulations to show that the size distribution of intrusions preserved as plutonic complexes in the North American Cordillera suggests a transition in the mechanical response of crustal rocks to protracted episodes of magmatism. Intrusion sizes larger than about 100?m follow a power-law scaling expected if energy delivered from the mantle to open very thin dykes and sills is transferred to intrusions of increasing size. Merging, assimilation and mixing of small intrusions into larger ones occurs until irreversible deformation and solidification dissipate available energy. Mantle magma supply over tens to hundreds of thousands of years will trigger this regime, a type of reverse energy cascade, depending on the influx rate and efficiency of crustal heating by intrusions. Identifying regimes of magma transport provides a framework for inferring subsurface magmatic processes from surface patterns of volcanism, information preservation in the plutonic record, and related effects including climate.
DS201908-1781
2019
Jellinek, A.M.Jellinek, A.M., Lenardic, A., Pierrehumbert, R.T.Ice, fire or fizzle: the climate footprint of Earth's supercontinental cycles.Geochemistry, Geophysics, Geosystems, in press, 59p. PdfMantleNuna
DS202003-0343
2020
Jellinek, M.Jellinek, M., Lenardic, A., Pierrehumbert, R.T.Ice, fire, or fizzle: the climate footprint of Earth's supercontinental cycles.Geochemistry, Geophysics, Geosystems, Vol. 21, 2, 66p. PdfMantlegeodynamics

Abstract: Supercontinent assembly and breakup can influence the rate and global extent to which insulated and relatively warm subcontinental mantle is mixed globally, potentially introducing lateral oceanic?continental mantle temperature variations that regulate volcanic and weathering controls on Earth's long?term carbon cycle for a few hundred million years. We propose that the relatively warm and unchanging climate of the Nuna supercontinental epoch (1.81.3 Ga) is characteristic of thorough mantle thermal mixing. By contrast, the extreme cooling?warming climate variability of the Neoproterozoic Rodinia episode (10.63 Ga) and the more modest but similar climate change during the Mesozoic Pangea cycle (0.30.05 Ga) are characteristic features of the effects of subcontinental mantle thermal isolation with differing longevity. A tectonically modulated carbon cycle model coupled to a one?dimensional energy balance climate model predicts the qualitative form of Mesozoic climate evolution expressed in tropical sea?surface temperature and ice sheet proxy data. Applied to the Neoproterozoic, this supercontinental control can drive Earth into, as well as out of, a continuous or intermittently panglacial climate, consistent with aspects of proxy data for the Cryogenian?Ediacaran period. The timing and magnitude of this cooling?warming climate variability depends, however, on the detailed character of mantle thermal mixing, which is incompletely constrained. We show also that the predominant modes of chemical weathering and a tectonically paced abiotic methane production at mid?ocean ridges can modulate the intensity of this climate change. For the Nuna epoch, the model predicts a relatively warm and ice?free climate related to mantle dynamics potentially consistent with the intense anorogenic magmatism of this period.
DS202106-0951
2021
Jellinek, M.Le Pichon, X., Jellinek, M., Lenardic, A., Sengor, A.M.C., Imren, C.Pangea migration.Tectonics, e2020TC006585 42p. PdfMantleplate tectonics

Abstract: We confirm the proposition of Le Pichon et al. (2019) that Pangea was ringed by a hemispheric subduction girdle from its formation 400 Ma to its dispersal 100 Ma. We quantify the northward migration, that we attribute to True Polar Wander (TPW), of its axis of symmetry, between 400 Ma and 150 Ma, from southern latitudes to the equatorial zone. The spatial stabilizing within the equatorial zone of the axis of symmetry in a fixed position with respect to lower mantle, was marked by alternating CW and CCW oscillations between 250 Ma and 100 Ma that we relate to tectonic events. A subduction girdle is predicted to set up lateral temperature gradients from relatively warm sub-Pangean mantle to cooler sub-oceanic mantle. Over time, this effect acts to destabilize the Pangea landmass and its associated subduction girdle. Quantitatively, a scaling theory for the stability of the subduction girdle against mantle overturn constrains the maximum magnitude of sub-Pangean warming before breakup to be order 100 oC, consistent with constraints on Pacific-Atlantic oceanic crustal thickness differences. Our predictions are in line with recent analyses of Jurassic-Cretaceous climate change and with existing models for potential driving forces for a TPW oscillation of Pangea across the equator. The timing and intensity of predicted sub-Pangean warming potentially contributed to the enigmatically large Siberian Traps and CAMP flood basalts at 250 Ma and 201 Ma, respectively.
DS202201-0023
2021
Jellinek, M.Lenardic, A.,Jellinek, M.,Seales, J., Lee, C-T.Global tectonic and climatic fluctuations: from Pangea grounding to planetary speculation. * just for interestResearchgate , Dec. 51p. PdfGlobalGeotectonics

Abstract: The Earth's paleo-climate record indicates climate fluctuations, from cool to warm to cool conditions, over the last ~300 My. Over that time, the Earth's most recent super-continent, Pangea, formed and broke apart. Data constraints together with numerical models indicate that Pangea formation and breakup affected spatial and temporal patterns of heat loss from the Earths' interior. This, in turn, affected global tectonic and volcanic behavior. The tectonic/volcanic fluctuations can be linked to climate models to explore the degree to which they could drive long time scale (~100 My) climate variations. The coupled models indicate that Pangea-driven tectonic fluctuations can lead to climate fluctuations consistent with data constraints. Global variations in the tectonic behavior of the Earth, linked to climate variations, has implication for understanding how the internal evolution of a planet can affect surface environments. We will end with some speculations on how that could feed into planetary habitability.
DS200912-0341
2009
JelsmaJones, A.G., Evans, Muller, Hamilton, Miensopust, Garcia, Cole, Ngwisanyi, Hutchins, Stoffel Fourie, Jelsma, Aravanis, Petit, Webb, WasborgArea selection for diamonds using magnetotellurics: examples from southern Africa.Lithos, In press - available 35p.Africa, South Africa, BotswanaGeophysics - magnetotellurics
DS201112-0312
2011
JelsmaEvans, R.L., Jones, A.G., Garcia, X., Muller, M., Hamilton, Evans, Fourie, Spratt, Webb, Jelsma, HutchinsElectrical lithosphere beneath the Kaapvaal craton, southern Africa.Journal of Geophysical Research, Vol. 116, B4, B04105.Africa, South AfricaGeophysics - seismics
DS201412-0068
2014
JelsmaBraun, J., Guillocheau, F., Robin, C., Baby, Guillaume, JelsmaRapid erosion of the southern African plateau as it climbs over a mantle superswell.Journal of Geophysical Research,, Vol. 119, 7, pp. 6093-6112.Africa, southern AfricaGeomorphology
DS200912-0522
2009
Jelsma, Aravanis.PettitMuller, M.R., Jones, Evans, Grutter, Hatton, Garcia, Hamilton, Miensopust, Cole, Ngwisanyi, Hutchins, Fourie, Jelsma,Aravanis.Pettit, Webb, WasborgLithospheric structure, evolution and diamond prospectivity of the Rehoboth Terrane and western Kaapvaal Craton, southern Africa: constraints from broadbandLithos, In press - available 57p..Africa, South Africa, BotswanaGeophysics - broadband magnetotellurics
DS1999-0168
1999
Jelsma, H.Dirks, P., Jelsma, H., MunyanyiwaIntraplate magmatism and tectonics of southern AfricaJournal of African Earth Sciences, Vol. 28, No. 2, Feb. pp. 285-88.South AfricaMagmatism
DS2002-0116
2002
Jelsma, H.Basson, I.J., Jelsma, H., Viola, G.Rapid kimberlitic fluid extraction from mantle lithosphere11th. Quadrennial Iagod Symposium And Geocongress 2002 Held Windhoek, Abstract p. 20.AfricaMelting - LPO orientation
DS200512-0477
2005
Jelsma, H.Jelsma, H., Smith, C., Barton, E., Barnett, W.Geodynamic setting of kimberlites. Genome.GAC Annual Meeting Halifax May 15-19, Abstract 1p.GlobalTectonics
DS200912-0336
2009
Jelsma, H.Jelsma, H., Barnett, W., Richards, S., Lister, G.Tectonic setting of kimberlites.Lithos, In press - available 30p.Africa, South AfricaTectonics
DS201212-0056
2012
Jelsma, H.Barnett, W., Jelsma, H., Watkeys, M., FreemanHow structure and stress influence the location of kimberlites.10th. International Kimberlite Conference Feb. 6-11, Bangalore India, AbstractGlobalGeotectonics
DS201212-0229
2012
Jelsma, H.Garanin, V.K., Anashkin, S.M., Bovkun, A.V., Jelsma, H., Shmakov, I.I., Garanin, K.V.Groundmass microcrystalline oxides from the Marsfontein pipe ( RSA) , Catoca, Camachia and other Angolan kimberlite pipes.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractAfrica, Angola, South AfricaDeposit - Marsfontein, Catoca, Camachia
DS201212-0339
2012
Jelsma, H.Jelsma, H.,Krishnan, S.U., Perritt, S.,Kumar, M., Preston, R., Winter, F., Lemotlo, L., Costa, J., Van der Linde, G., Facatino, M., Posser, A., Wallace, C., Henning, A., Joy, S., Chinn, I., Armstrong, R., Phillips, D.Kimberlites from central Angola: a case stidy of exploration findings.10th. International Kimberlite Conference Feb. 6-11, Bangalore India, AbstractAfrica, AngolaOverview of kimberlites
DS201212-0553
2012
Jelsma, H.Phillips, D., Giullani, A., Jelsma, H., Joy, S.40Ar/39AR analyses of kelphite: a new approach for dating kimberlites and related rocks.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractAfrica, South Africa, AngolaDeposit Dando Kwanza
DS201312-0054
2013
Jelsma, H.Barnett, W., Jelsma, H., Watkeys, M.How structure and stress influence kimberlite emplacement.Proceedings of the 10th. International Kimberlite Conference, Vol. 2, Special Issue of the Journal of the Geological Society of India,, Vol. 2, pp. 51-65.Africa, South AfricaKimberley district - dykes
DS201312-0439
2013
Jelsma, H.Jelsma, H., Krishnan, U.Kimberlites from central Angola: a case study of exploration findings.Proceedings of the 10th. International Kimberlite Conference, Vol. 2, Special Issue of the Journal of the Geological Society of India,, Vol. 2, pp. 173-190.Africa, AngolaDeposit - Dando-Kwanza
DS201312-0593
2013
Jelsma, H.McCourt, S., Armstrong, R.A., Jelsma, H., Mapeo, R.B.M.New U-Pb SHRIMP ages from the Lubango region, sw Angola: insights into the Paleoproterozoic evolution of the Angolan shield, southern Congo craton, Africa.Journal of the Geological Society, Vol. 170, pp. 353-363.Africa, AngolaGeochronology
DS201412-0037
2013
Jelsma, H.Barnett, W., Jelsma, H., Watkeys, M., Freeman, L., Bloem, A.How structure and stress influence kimberlite emplacement.Proceedings of the 10th. International Kimberlite Conference, Vol. 2, pp. 51-66.Africa, South AfricaKimberley District - dyke modeling
DS201412-0427
2013
Jelsma, H.Jelsma, H., Krishnan, U., Perritt, S., Preston, R., Winter, F., Lemotlo, L., van der Linde, G., Armstrong, R., Phillips, D., Joy, S., Costa, J., Facatino, M., Posser, A., Kumar, M., Wallace, C., Chinn, I., Henning, A.Kimberlites from central Angola: a case study of exploration findings.Proceedings of the 10th. International Kimberlite Conference, Vol. 2, pp. 173-190.Africa, AngolaExploration - kimberlites
DS201412-0428
2014
Jelsma, H.Jelsma, H., Tappe, S.Kimberlites and supercontinent cyclicity.GSSA Kimberley Diamond Symposium and Trade Show provisional programme, Sept. 12, title onlyGlobalKimberlite genesis
DS1993-0744
1993
Jelsma, H.A.Jelsma, H.A., Van der Beek, P.A., Vinyu, M.L.Tectonic evolution of the Bindura-Shamva greenstone belt (northernZimbabwe): progressive deformation around diapiric batholithsJournal of Structural Geology, Vol. 15, No. 2, pp. 165-176ZimbabweStructure, Greenstone belt
DS1996-0683
1996
Jelsma, H.A.Jelsma, H.A., Vinyu, M.L., Verdurmen, E.A.T.Constraints on Archean crustal evolution of the Zimbabwe craton: a uranium-lead (U-Pb) (U-Pb)zircon, samarium-neodymium (Sm-Nd),lead-lead studyChemical Geology, Vol. 129, No. 3/4, July 29, pp. 55-81Zimbabwe, South AfricaGeochronology, Craton
DS1998-0352
1998
Jelsma, H.A.Dirks, P.H.G., Jelsma, H.A.Horizontal accretion and stabilization of the Archean Zimbabwe CratonGeology, Vol. 26, No. 1, Jan. pp. 11-14.ZimbabweTectonics, Craton
DS1998-0353
1998
Jelsma, H.A.Dirks, P.H.G.M., Jelsma, H.A., Vinyu, M., MunyanyiwaThe structural history of the Zambesi Belt in northeast Zimbabwe: evidence for crustal extension - Pan AfricanSouth African Journal of Geology, Vol. 101, No. 1, March pp. 1-16ZimbabweStructure, Orogeny - Pan-African
DS2001-0532
2001
Jelsma, H.A.Jelsma, H.A., Dirks, P.H.G.M.Crustal growth and formation of the Zimbabwe CratonGeological Association of Canada (GAC) Annual Meeting Abstracts, Vol. 26, p.73, abstract.ZimbabweGeochronology, Lineaments
DS2002-0383
2002
Jelsma, H.A.Dirks, P.H.G.M., Jelsma, H.A.Crust mantle decoupling and the growth of the Archean Zimbabwe cratonJournal of African Earth Sciences, Vol.34, No.3-4,April-May pp. 157-66.ZimbabweTectonics
DS2002-0384
2002
Jelsma, H.A.Dirks, P.H.G.M., Jelsma, H.A., Hofman, A.Thrust related accretion of an Archean greenstone belt in the midlands of ZimbabweJournal of Structural Geology, Vol.24, 11, Nov. pp. 1707-27.ZimbabweTectonics
DS2002-0776
2002
Jelsma, H.A.Jelsma, H.A., Dirks, P.H.G.M.Tectono-magmatic evolution of the Zimbabwe CratonGeological Society of London Special Publication, No. 199, pp. 183-212.ZimbabweTectonics, Magmatism
DS2002-0777
2002
Jelsma, H.A.Jelsma, H.A., Dirks, P.H.G.M., De Wit, M.J.Tectonics and metallogeny of Archean lithosphere in southern Africa11th. Quadrennial Iagod Symposium And Geocongress 2002 Held Windhoek, Abstract p. 28.South AfricaMagmatism
DS200412-0911
2004
Jelsma, H.A.Jelsma, H.A., De Wit, M.J., Thiart, C., Dirks, P.H.G.M., Viola, G., Basson, U., Anckar, E.Preferential distribution along transcontinental corridors of kimberlites and related rocks of Southern Africa.South African Journal of Geology, Vol. 107, 1/2, pp. 302-324.Africa, South AfricaTectonics, structures, lineaments
DS200612-0335
2006
Jelsma, H.A.Dirks, P.H.G.M., Jelsma, H.A.The structural metamorphic evolution of the northern margin of the Zimbabwe Craton and the adjacent Zambezi belt in northeastern Zimbabwe.Geological Society of America, Special Paper 405, pp. 291-314.Africa, ZimbabweCraton
DS201212-0343
2012
Jelsma, H.A.Joy, S., Jelsma, H.A., Preston, R.F., Kota, S.Geology and diamond provenance of the Proterozoic Banganapalle conglomerates, Kurnool Group, India.Geological Society of London Special Publication, No. 365, pp. 197-218.IndiaDeposit - Banganapalle
DS201503-0141
2015
Jelsma, H.A.De Wit, M.C.J., Jelsma, H.A.A review of the kimberlites of the Democratic Republic of Congo.Geology and resource potential of the Congo Basin, Springer Regional Geology Reviews, Chapter 17, 9p.Africa, Democratic Republic of CongoOverview, history

Abstract: An overview is provided of the exploration history and geological setting of the kimberlites in the Democratic Republic of Congo (DRC). Exploration for diamonds, in what was then known as Congo Belge, started in 1900 and the first diamonds were found in 1903 in Shaba (now Katanga) Province, in 1907 in Kasai Occidental Province near Tshikapa Town and in 1918 in Kasai Oriental Province near Mbuji Mayi Town. While the Kundelungu kimberlites in Katanga Province were discovered in 1908, other kimberlite fields were discovered much later (Mbuji Mayi 1946; Tshibwe 1956; Bas-Congo 1974; Kasendou and Lukashi 2005), during exploration work by Forminière (Société Internationale Forestière et Minière du Congo-Tshikapa), MIBA (Societé Minière de Bakwanga-Mbuji Mayi), the De Beers Group and Bugeco S.A. Published age constraints on the kimberlites show Late Cretaceous ages for the Mbuji Mayi kimberlites (~70 Ma) and Eocene-Oligocene ages for the Kundelungu kimberlites (~32 Ma). Emplacement of the Late Cretaceous kimberlites (Mbuji Mayi, Tshibwe, Kasendou and Lukashi) was concomitant with the deposition of Cretaceous sedimentary sequences. The majority of the pipes show crater-facies preservation and some of the pipes are flared displaying so-called ‘champagne glass-shaped’ morphologies, suggesting emplacement into unconsolidated sediments overlying basement. The age of the Eocene-Oligocene Kundelungu kimberlites corresponds to lithospheric extension associated with the southward propagation of the East African Rift.
DS201710-2235
2017
Jelsma, H.A.Koornneef, J.M., Gress, M.U., Chinn, I.L., Jelsma, H.A., Harris, J.W., Davies, G.R.Archaean and Proterozoic diamond growth from contrasting styles of large scale magmatism.Nature Communications, Vol. 8, 10.1038/s41467-017-00564-xAfrica, South Africadiamond inclusions

Abstract: Precise dating of diamond growth is required to understand the interior workings of the early Earth and the deep carbon cycle. Here we report Sm-Nd isotope data from 26 individual garnet inclusions from 26 harzburgitic diamonds from Venetia, South Africa. Garnet inclusions and host diamonds comprise two compositional suites formed under markedly different conditions and define two isochrons, one Archaean (2.95?Ga) and one Proterozoic (1.15?Ga). The Archaean diamond suite formed from relatively cool fluid-dominated metasomatism during rifting of the southern shelf of the Zimbabwe Craton. The 1.8 billion years younger Proterozoic diamond suite formed by melt-dominated metasomatism related to the 1.1?Ga Umkondo Large Igneous Province. The results demonstrate that resolving the time of diamond growth events requires dating of individual inclusions, and that there was a major change in the magmatic processes responsible for harzburgitic diamond formation beneath Venetia from the Archaean to the Proterozoic.
DS202106-0944
2021
Jelsma, H.A.Jelsma, H.A., Nesbitt, R.W., Fanning, C.M.Exploring our current understanding of the geological evolution and mineral endowment of the Zimbabwe craton.South African Journal of Geology, Vol. 124, 1, pp. 279-301. pdfAfrica, Zimbabwecraton

Abstract: A.M. Macgregor (1888-1961) is remembered for his enormous contribution to geology. His maps changed the course of geological thinking in southern Africa. Following in his footsteps we examine aspects of our current understanding of the geological evolution of the Zimbabwe Craton and, using new SHRIMP U-Pb ages of zircons from felsic volcanic and plutonic rocks from northern Zimbabwe and unpublished data related to the seminal paper by Wilson et al. (1995), a synthesis is proposed for the formation of the Neoarchaean greenstones. The data suggest marked differences (lithostratigraphy, geochemistry and isotope data, mineral endowment and deformational history), between Eastern and Western Successions, which indicate fundamentally different geodynamic environments of formation. The Eastern Succession within the southcentral part of the craton, largely unchanged in terms of stratigraphy, is reminiscent of a rift-type setting with the Manjeri Formation sediments and overlying ca. 2 745 Ma Reliance Formation komatiite magmatism being important time markers. In contrast, the Western Succession is reminiscent of a convergent margin subduction-accretion system with bimodal mafic-felsic volcanism and accompanying sedimentation constrained to between 2 715 and 2 683 Ma. At ca. 2 670 Ma, a tectonic switch likely marks the onset of deposition of Shamvaian felsic volcanism and sedimentation. The Shamvaian resembles pull-apart basin successions and is dominated by deposition of a coarse clastic sedimentary succession, with deposition likely constrained to between 2 672 and 2 647 Ma. The late tectonic emplacement of small, juvenile multiphase stocks, ranging in composition from gabbroic to granodioritic was associated with gold ± molybdenum mineralisation. Their emplacement at 2 647 Ma provides an upper age limit to the timespan of Shamvaian deposition. Amongst the youngest granites are the extensive, largely tabular late- to post-tectonic ca. 2 620 to 2 600 Ma Chilimanzi Suite granites. These granites are characterised by evolved isotopic systems and have been related to crustal relaxation and anatexis following deformation events. After their emplacement, the Zimbabwe Craton cooled and stabilised, with further deformation partitioned into lower-grade, strike-slip shear zones, and at ca. 2 575 Ma the craton was cut by the Great Dyke, its satellite dykes and related fractures.
DS201911-2526
2019
Jemenez, P.Giampouras, M., Garrido, C.J., Zwicker, J., Vadillo, I., Smrzka, D., Bach, W., Peckmann, J., Jemenez, P., Benavente, J., Garcia-Ruiz, J.M.Geochemistry and mineralogy of serpentinization driven hyperalkaline springs in the Ronda peridotite.Lithos, doi 10.1016/j.lithos.2019.105215, 75p. PdfEurope, Spaindeposit - Ronda

Abstract: We present a detailed study of the water geochemistry, mineralogy and textures in serpentinization-related hyperalkaline springs in the Ronda peridotites. Ronda waters can be classified into hyperalkaline fluids and river waters that are broadly similar to Ca2+-OH- and Mg2+-HCO3- water types described in serpentinite-hosted alkaline springs elsewhere. At the discharge sites of the fluids (fractures or human made outlets) and ponds along the fluid flow paths, the fluids are hyperalkaline (10.9 < pH < 12) and characterized by low Mg and high Na, K, Ca, and Cl concentrations. River waters, occurring near the spring sites, are mildly alkaline (8.5 < pH < 8.9) and enriched in Mg and DIC compared to Na, K, Ca and Cl. The chemistry of Ronda Mg-HCO3 river waters is likely due to the hydrolysis of ferromagnesian peridotite minerals in equilibrium with the atmosphere by infiltrated meteoric water and shallow groundwater in the serpentinized peridotite. The Ronda Ca-OH hyperalkaline fluids are generated by the combination of low temperature serpentinization reactions from infiltrated surface Mg-HCO3 river waters —or Ca-HCO3 waters from near karst aquifers— and deep carbonate precipitation isolated from atmospheric CO2. Mass balance calculations indicate that the weathering of Ca-bearing peridotite silicates such as diopside is a feasible source of Ca in Ronda Ca-OH hyperalkaline fluids; however, it requires steady-state dissolution rates substantially greater than those determined experimentally. Travertine, crystalline crusts and sediment deposits are the main types of solid precipitates observed in Ronda hyperalkaline spring sites. Calcite and aragonite, minor dolomite and Mg-Al-rich clays are the main minerals in the spring sites. As illustrated in the Baños del Puerto spring site, (i) calcite-dominated precipitation is due to hyperalkaline fluid uptake of atmospheric CO2 during discharge, and (ii) aragonite-dominated precipitation is due to mixing of Ca-OH hyperalkaline fluids with Mg- HCO3 river waters. Aragonite and dolomite contents increase away from the springs and toward the river waters that uniquely reflects the effect of Mg ions on the precipitation of aragonite versus calcite. Other potential factors controlling the precipitation of these CaCO3 polymorphs are the Mg/Ca ratio, the CO2 content, and the temperature of the fluids. Dolomite forms during lithification of travertine due to periodic flooding of river water combined with subsequent evaporation.
DS201112-0481
2011
Jemenez-Munt, I.Jemenez-Munt, I., Fernandez, M., Verges, J., Garcia-Castellanos, D., Fullea, J., Perez-Gussinye, M., Afonso, J.C.Decoupled crust mantle accommodation of Africa-Eurasia convergence in the NW Moroccan margin.Journal of Geophysical Research, Vol. 116, B08403, 12p.Africa, MoroccoGeophysics - density
DS1997-0853
1997
Jemielita, R.Noble, S.R., Aspden, J.A., Jemielita, R.Northern Andean crustal evolution: new uranium-lead (U-Pb) geochronological constraints from EcuadorGeological Society of America (GSA) Bulletin, Vol. 109, No. 7, pp. 789-798EcuadorTectonics, Geochronology, Cordillera
DS1998-0694
1998
Jen, L.S.Jen, L.S.Implications of new mine developments in Canada for Canadian and global mining and production 1997-2000The Canadian Mining and Metallurgical Bulletin (CIM Bulletin), Vol. 91, No. 1023, Sept. pp. 61-68CanadaMines - list, Economics, reserves, resources, discoveries
DS1995-1906
1995
Jenatton, L.Thouvenot, F., Kasubin, S.N., Jenatton, L.The root of the Urals: evidence from wide angle reflection seismicsTectonophysics, Vol. 250, No. 1/3, Nov. 15, pp. 1-14.GlobalGeophysics -seismics, Tectonics
DS1988-0328
1988
Jenden, P.D.Jenden, P.D., Newell, K.D., Kaplan, I.R., Watney, W.L.Composition and stable isotope geochemistry of natural gases from Kansas, Midcontinent, USAChemical Geology, Vol. 71, No. 1/3. December 15, pp. 117-148MidcontinentGeochemistry, Gases
DS200412-0942
2004
Jendrzejewski, N.Kadik, A., Pineau, F., Litvin, Y., Jendrzejewski, N., Martinez, I., Javoy, M.Formation of carbon and hydrogen species in magmas at low oxygen fugacity.Journal of Petrology, Vol. 45, 7, pp. 1297-1310.TechnologyMagmatism - not specific to diamonds
DS2001-0162
2001
Jendrzewski, N.Cartigny, P., Jendrzewski, N., Pineau, F., Petit, JavoyVolatile (Carbon,Nitrogen,Argon) variability in MORB and respective roles of mantle source heterogenity and degassing: caseEarth and Planetary Science Letters, Vol. 194, No. 1-2, pp. 241-57.Indian RidgeBasaltic glasses - geochemistry, Argon, Carbon, Nitrogen, MORB
DS201412-0058
2014
Jenett, T.Boger, S.D., Hirdes, W., Ferreira, C.A.M., Jenett, T., Dallwig, R., Fanning, C.M.The 580-520 Ma Gondwana suture of Madagascar and its continuation into Antarctica and Africa.Gondwana Research, in press available 14p.Africa, MadagascarShield - Arabian Nubian
DS201509-0385
2015
Jenett, T.Boger, S.D., Hirdes, W., Ferreira, C.A.M., Jenett, T., Dallwig, R., Fanning, C.M.The 580-520 Ma Gondwana suture of Madagascar and its continuation into Antarctica and Africa.Gondwana Research, Vol. 28, pp. 1048-1060.Africa, MadagascarTectonics

Abstract: U-Pb age data from southwest Madagascar provide a compelling case that the pre-Gondwana Indian plate was stitched with the arc terranes of the Arabian Nubian Shield along a suture that closed between 580 Ma and 520 Ma. The key observations supportive of this interpretation are: (1) metamorphism dated to 630-600 Ma is manifested only on the west side of the suture in rocks that have affinities with the oceanic and island arc terranes of the Arabian Nubian Shield, or which represent continental rocks welded to these terranes prior to the amalgamation of Gondwana, and (2) orogenesis at 580-520 Ma is manifest in rocks on both sides of the suture, an observation taken to mark the timing of collision and to reflect spatial continuity across the suture. In southwest Madagascar the distribution of metamorphic ages places the suture along the Beraketa high-strain zone, the tectonic boundary between the Androyen and Anosyen domains. Similar age relationships allow for the extrapolation of this tectonic boundary into both East Antarctica and Africa.
DS201905-1017
2019
Jenett, T.Boger, S.D., Maas, R., Pastuhov, M., Macey, P.H., Hirdes, W., Schulte, B., Fanning, C.M., Ferreira, C.A.M., Jenett, T., Dallwig, R.The tectonic domains of southern and western Madagascar.Precambrian Research, Vol. 327, pp. 144-175.Africa, Madagascarplate tectonics

Abstract: Southern and western Madagascar is comprised of five tectonic provinces that, from northeast to southwest, are defined by the: (i) Ikalamavony, (ii) Anosyen, (iii) Androyen, (iv) Graphite and (v) Vohibory Domains. The Ikalamavony, Graphite and Vohibory Domains all have intermediate and felsic igneous protoliths of tonalite-trondhjemite-granodiorite-granite composition, with positive ?Nd, and low Sr and Pb isotopic ratios. All three domains are interpreted to be the products of intra-oceanic island arc magmatism. The protoliths of the Ikalamavony and Graphite Domains formed repectively between c. 1080-980?Ma and 1000-920?Ma, whereas those of the Vohibory Domain are younger and date to between c. 670-630?Ma. Different post-formation geologic histories tie the Vohibory-Graphite and Ikalamavony Domains to opposite sides of the pre-Gondwana Mozambique Ocean. By contrast, the Androyen and Anosyen Domains record long crustal histories. Intermediate to felsic igneous protoliths in the Androyen Domain are of Palaeoproterozoic age (c. 2200-1800?Ma), of tonalite-trondhjemite-granodiorite-granite composition, and show negative ?Nd, moderate to high 87Sr/86Sr and variable Pb isotopic compositions. The felsic igneous protoliths of the Anosyen Domain are of granitic composition and, when compared to felsic gneisses of the Androyen Domain, show consistently lower Sr/Y and markedly higher Sr and Pb isotope ratios. Like the Vohibory and Graphite Domains, the Androyen Domain can be linked to the western side of the Mozambique Ocean, while the Anosyen Domain shares magmatic and detrital zircon commonalities with the Ikalamavony Domain. It is consequently linked to the opposing eastern side of this ocean. The first common event observed in all domains dates to c. 580-520?Ma and marks the closure of the Mozambique Ocean. The trace of this suture lies along the boundary between the Androyen and Anosyen Domains and is defined by the Beraketa high-strain zone.
DS1989-0365
1989
Jen-HoDonahoe, J.L., Green, N.L., Fang, Jen-HoAn expert system for idenification of minerals in thin sectionJournal of Geology Education, Vol. 37, No. 1, pp. 4-6. Database # 17586GlobalGIS - Mineralogy, Computer- Expert system
DS1983-0330
1983
Jenke, G.Jenke, G.The Role of Geophysics in the Discovery of the Ellendale And Fitzroy Kimberlites.Third Biennial Conference of The Australian Society of Exploration Geo, Oct. 31ST. TO Nov. 3RD. EXTENDED ABSTRACT VOLUME, PP. 66-72.Australia, Western Australia, ArgyleKimberlite, Geophysics
DS1994-0841
1994
Jenke, G.Jenke, G., Cowan, D.R.Geophysical signature of the Ellendale lamproite pipes, western AustraliaUniversity of Western Australia, Publishing No. 26, pp. 403-414.AustraliaGeophysics, Deposit -Ellendale
DS1983-0288
1983
Jenke, G.P.Harvey, B.E., Jenke, G.P.El 3541 Harry Creek Annual Report for Period Ending 19/4/83Northern Territory Geological Survey Open File Report, No. CR 83/153, 18P.Australia, Northern TerritoryProspecting, Sampling, Geophysics, Geochemistry
DS1983-0289
1983
Jenke, G.P.Harvey, B.E., Jenke, G.P., Cra exploration pty. ltd.El 3501 Mud Tank Annual Report for Year Ending 19/4/83Northern Territory Geological Survey Open File Report, No. CR 83/154, 20P.Australia, Northern TerritoryProspecting, Geophysics, Geochemistry
DS1994-0842
1994
Jenkin, G.R.T.Jenkin, G.R.T., et al.Oxygen isotope exchange and closure temperatures in cooling rocksJournal of Metamorphic Geology, Vol. 12, No. 3, May pp. 221-236GlobalGeothermometry, metamorphism
DS1975-1083
1979
Jenkins, C.Jenkins, C.Otish Mountains, Jv West Project 71-85Quebec Department of Mines, GM 34301, 204p.QuebecGeology
DS1983-0331
1983
Jenkins, D.Jenkins, D.Paleomagnetism in the eastern Ouachita Mountains, Arkansaw and their tectonic implicationsMsc. Thesis, University of Florida, Gainesville, Midcontinent, ArkansasPaleomagnetism, Tectonics
DS1960-0464
1964
Jenkins, G.Jenkins, G.The River of DiamondsLondon: Collins, 256P.Southwest Africa, Namibia, South AfricaFiction, Kimberley, Orange River Diamonds
DS1992-0781
1992
Jenkins, I.Jenkins, I.Mining giants join great diamond rushLondon Financial Times, Business section, Oct. 25th. 1pNorthwest TerritoriesNews item, RTZ, BHP, Dia Met, De Beers
DS201512-1934
2015
Jenkins, J.Jenkins, J., Cottaar, S., White, R.S., Deuss, A.Depressed mantle discontinuities beneath Iceland: evidence of a garnet controlled 660 km discontinuity?Earth and Planetary Science Letters, Vol. 432, pp. 159-168.Europe, IcelandMantle plume

Abstract: The presence of a mantle plume beneath Iceland has long been hypothesised to explain its high volumes of crustal volcanism. Practical constraints in seismic tomography mean that thin, slow velocity anomalies representative of a mantle plume signature are difficult to image. However it is possible to infer the presence of temperature anomalies at depth from the effect they have on phase transitions in surrounding mantle material. Phase changes in the olivine component of mantle rocks are thought to be responsible for global mantle seismic discontinuities at 410 and 660 km depth, though exact depths are dependent on surrounding temperature conditions. This study uses P to S seismic wave conversions at mantle discontinuities to investigate variation in topography allowing inference of temperature anomalies within the transition zone. We employ a large data set from a wide range of seismic stations across the North Atlantic region and a dense network in Iceland, including over 100 stations run by the University of Cambridge. Data are used to create over 6000 receiver functions. These are converted from time to depth including 3D corrections for variations in crustal thickness and upper mantle velocity heterogeneities, and then stacked based on common conversion points. We find that both the 410 and 660 km discontinuities are depressed under Iceland compared to normal depths in the surrounding region. The depression of 30 km observed on the 410 km discontinuity could be artificially deepened by un-modelled slow anomalies in the correcting velocity model. Adding a slow velocity conduit of ?1.44% reduces the depression to 18 km; in this scenario both the velocity reduction and discontinuity topography reflect a temperature anomaly of 210 K. We find that much larger velocity reductions would be required to remove all depression on the 660 km discontinuity, and therefore correlated discontinuity depressions appear to be a robust feature of the data. While it is not possible to definitively rule out the possibility of uncorrected velocity anomalies causing the observed correlated topography we show that this is unlikely. Instead our preferred interpretation is that the 660 km discontinuity is controlled by a garnet phase transition described by a positive Clapeyron slope, such that depression of the 660 is representative of a hot anomaly at depth.
DS201602-0214
2016
Jenkins, J.Jenkins, J., Cottaar, S., White, R.S., Deuss, A.Depressed mantle discontinuities beneath Iceland: evidence of a garnet controlled 660 km discontinuity?Earth and Planetary Science Letters, Vol. 433, pp. 159-168.Europe, IcelandMantle - 660 km

Abstract: The presence of a mantle plume beneath Iceland has long been hypothesised to explain its high volumes of crustal volcanism. Practical constraints in seismic tomography mean that thin, slow velocity anomalies representative of a mantle plume signature are difficult to image. However it is possible to infer the presence of temperature anomalies at depth from the effect they have on phase transitions in surrounding mantle material. Phase changes in the olivine component of mantle rocks are thought to be responsible for global mantle seismic discontinuities at 410 and 660 km depth, though exact depths are dependent on surrounding temperature conditions. This study uses P to S seismic wave conversions at mantle discontinuities to investigate variation in topography allowing inference of temperature anomalies within the transition zone. We employ a large data set from a wide range of seismic stations across the North Atlantic region and a dense network in Iceland, including over 100 stations run by the University of Cambridge. Data are used to create over 6000 receiver functions. These are converted from time to depth including 3D corrections for variations in crustal thickness and upper mantle velocity heterogeneities, and then stacked based on common conversion points. We find that both the 410 and 660 km discontinuities are depressed under Iceland compared to normal depths in the surrounding region. The depression of 30 km observed on the 410 km discontinuity could be artificially deepened by un-modelled slow anomalies in the correcting velocity model. Adding a slow velocity conduit of ?1.44% reduces the depression to 18 km; in this scenario both the velocity reduction and discontinuity topography reflect a temperature anomaly of 210 K. We find that much larger velocity reductions would be required to remove all depression on the 660 km discontinuity, and therefore correlated discontinuity depressions appear to be a robust feature of the data. While it is not possible to definitively rule out the possibility of uncorrected velocity anomalies causing the observed correlated topography we show that this is unlikely. Instead our preferred interpretation is that the 660 km discontinuity is controlled by a garnet phase transition described by a positive Clapeyron slope, such that depression of the 660 is representative of a hot anomaly at depth.
DS1987-0390
1987
Jenkins, M.J.Kurtz, M.D., Gurney, J.J., Jenkins, M.J., Lott, D.E.Helium isotopic variability within single diamonds from the Orapa kimberlite pipeEarth Planet. Sci. Letters, Vol. 86, No. 1, November pp. 57-68BotswanaBlank
DS2002-0778
2002
Jenkins, R.B.Jenkins, R.B., Landenberger, B., Collins, W.J.Late Paleozoic retreating and advancing subduction boundary in the New England fold belt, New South Wales.Australian Journal of Earth Sciences, Vol.49, No. 3, pp. 467-90.AustraliaSubduction
DS1997-0756
1997
Jenkins, R.J.F.McIlroy, D., Jenkins, R.J.F., Walter, M.R.The nature of the Proterozoic Cambrian transition in the northern AmadeusBasin, central AustraliaPrecambrian Research, Vol. 86, No. 1/2, Dec. 15, pp. 93-AustraliaProterozoic, Boundary
DS1996-0433
1996
Jenkins, S.L.Eriksson, P.G., Reczko, B.F.F., Jenkins, S.L.The Kanye axis, Kaapvaal Craton, a postulated Archean crustal architectural element - 3D basin modeling..Journal of African Earth Science, Vol. 22, No. 3, April 1, pp. 223-234South AfricaGeophysics -structure basin, Craton -Kaapvaal
DS200412-1894
2004
Jenkins, W.J.Srinivasan, A., Top,Z., Sclosser, P., Hohmann, R., Iskandarani, M., Olson, D.B., Lupton, J.E., Jenkins, W.J.Mantle 3 He distribution and deep circulation in the Indian Ocean.Journal of Geophysical Research, Vol. 109, 6, 10.1029/2003 JC002028Indian OceanMineralogy
DS1991-0789
1991
Jenks, P.J.Jenks, P.J., Sinha, A.K., Essex, R.Late Proterozoic magmatism in the eastern United States: neodymium, lead and Strontium isotope systematics and implications for crust-mantle interactionsGeological Society of America Annual Meeting Abstract Volume, Vol. 23, No. 5, San Diego, p. A 135AppalachiaCrust, Geochronology
DS1998-1534
1998
JennerVeksler, I.V., Petibon, Jenner, Dorfman, DingwellTrace element partitioning in immiscible silicate carbonate liquid systems:an initial experimenatal ...Journal of Petrology, Vol. 39, No. 11-12, Nov-Dec. pp. 2095-2104.MantleCarbonatite, Petrology - experimental
DS200712-0070
2006
Jenner, F.Bennett, V., Nutman, A., Jenner, F., Friend, C.Variable styles of crust evolution recorded in oldest ( 3.7 - 3.85 Ga) rock and >4.0 Ga mineral suites?Geochimica et Cosmochimica Acta, In press availableAustraliaGeochronology
DS201012-0531
2009
Jenner, F.E.Nebel, O., Vroon, P.Z., Wiggers de Vries, D.F., Jenner, F.E., Mavrogenes, J.A.Tungsten isotopes as tracers of core mantle interactions: the influence of subducted sediments.Geochimica et Cosmochimica Acta, Vol. 74, 2, pp. 751-761.MantleSubduction
DS201909-2062
2019
Jenner, F.E.Mikhail, S., McCubbin, F.M., Jenner, F.E., Shirey, S.B., Rumble, D., Bowden, R.Diamonites: evidence for a distinct tectono-thermal diamond - forming event beneath the Kaapvaal craton.Contributions to Mineralogy and Petrology, in press available, 15p. PdfAfrica, South Africadiamondite
DS1991-0790
1991
Jenner, G.Jenner, G., Green, D.H.Petrogenesis of type 3 low Calcium boninitesEos Transactions, Vol. 72, No. 44, October 29, abstract p. 519GlobalBoninites, Petrology
DS1998-1156
1998
Jenner, G.Petibon, C.M., Kjarsgaard, B., Jenner, G., Jackson, S.Liquidus phase relationships of a silicate bearing natro carbonatite from Oldoinyo Lengai at 20, 100 Mpa.Journal of Petrology, Vol. 39, No. 11-12, Nov-Dec. pp. 2137-51.TanzaniaCarbonatite, Deposit - Oldoinyo Lengai
DS1989-0749
1989
Jenner, G.A.Karner, F.R., Halvorson, D., Jenner, G.A., White, S.F.Devils Tower-Black Hills alkalic igneous rock sand general geology. July1-7thAmerican Geophysical Union (AGU) 28th. International Geological Congress Field Trip Guidebook, No. T131, 88pWyomingBear Lodge Mountains, Alkaline rocks
DS1991-0791
1991
Jenner, G.A.Jenner, G.A., Dunning, G.R., Malpas, J., Brown, M., Brace, T.Bay of Islands and Little Port complexes, revisited: age, geochemical and isotopic evidence confirm suprasubduction-zone originCanadian Journal of Earth Sciences, Vol. 28, No. 10, October pp. 1635-1652NewfoundlandOphiolites, Geochronology
DS1994-0532
1994
Jenner, G.A.Foley, S.F., Jenner, G.A., Jackson, S.F., Fryer, B.J.Trace element partition coefficients phlogopite, clinopyroxene and matrixin alkaline lamprophyre.Mineralogical Magazine, Vol. 58A, pp. 280-281. AbstractNewfoundlandLamprophyre, Alkaline rocks -Notre Dame Bay
DS1994-0892
1994
Jenner, G.A.Kerr, A., Miller, R.R., Fryer, B.J., Jenner, G.A.Proterozoic and Paleozoic a type granite suites in Labrador andNewfoundland: samarium-neodymium (Sm-Nd) evidence for the importance of juvenile sources.Geological Association of Canada (GAC) Abstract Volume, Vol. 19, p.Labrador, NewfoundlandAlkaline rocks, Geochronology
DS1995-0546
1995
Jenner, G.A.Foley, S.F., Jenner, G.A., Konzett, J., Sweeney, R.J.Trace element partitioning in natural phlogopite and K richterite bearing xenoliths from southern Africa.Proceedings of the Sixth International Kimberlite Conference Extended Abstracts, p. 164-6.South AfricaXenoliths, Deposit -Bishoff dumps, Wesselton
DS1996-0460
1996
Jenner, G.A.Foley, S.F., Jackson, S.E., Jenner, G.A.Trace element partition coefficients for clinopyroxene and phlogopite in an alkaline lamprophyre from NewfoundlandGeochimica et Cosmochimica Acta, Vol. 60, No. 4, Feb. 1, pp. 629-638.NewfoundlandLamprophyre, Microscopy
DS1997-0904
1997
Jenner, G.A.Petibon, C.M., Jenner, G.A., Jackson, S.E., Kjarsgaard, B.Petrogenesis of Oldoinyo Lengai carbonatites: constraints from trace element partition coefficients.Geological Association of Canada (GAC) Abstracts, TanzaniaCarbonatite, Deposit - Oldoinyo Lengai
DS1998-0355
1998
Jenner, G.A.Dobosi, G., Jenner, G.A., Embey-Isztin, A.Clinopyroxene orthopyroxene trace element partition coefficients in spinel peridotite xenoliths.Mineralogical Magazine, Goldschmidt abstract, Vol. 62A, p. 393-4.Europe, Pannonian BasinLherzolite xenoliths
DS1998-1155
1998
Jenner, G.A.Petibon, C.M., Jenner, G.A., Kjarsgaard, B.A.The genesis of natrocarbonatites: constraints from experimental petrology and trace element partition....Mineralogical Magazine, Goldschmidt abstract, Vol. 62A, p. 1161-2.TanzaniaCarbonatite, Deposit - Oldoinyo Lengai
DS2001-0322
2001
Jenner, G.A.Foley, S.F., Petibon, C.M., Jenner, G.A., Kjarsgaard, B.High U Th partitioning by clinopyroxene from alkali silicate and carbonatite metasomatism: an origin for...Terra Nova, Vol. 13, pp. 104-9.TanzaniaNatrocarbonatite, uranium, thorium partitioning
DS2001-0714
2001
Jenner, G.A.MacHattie, T.G., Jenner, G.A., Corrigan, D.The Wathaman Batholith: evidence for role of enriched lithospheric mantle in a Proterozoic subduction zone.Geological Association of Canada (GAC) Annual Meeting Abstracts, Vol. 26, p.92.abstract.Saskatchewan, ManitobaTectonics, Subduction
DS2003-1358
2003
Jenner, G.A.Tappe, S., Foley, S.F., Jenner, G.A., Ryan, B., Besserer, D., Kjarsgaard, B.A.Ultramafic lamprophyre dykes from Labrador and New Quebec: mineralogy and8 Ikc Www.venuewest.com/8ikc/program.htm, Session 7, AbstractQuebec, LabradorKimberlite petrogenesis
DS200412-0565
2004
Jenner, G.A.Foley, S.F., Jenner, G.A.Trace element partitioning in lamproitic magmas - the Gaussberg olivine leucitite.Lithos, Vol. 75, 1-2, July, pp. 19-38.Europe, GermanyGeochemistry - fingerprinting, modelling origin, evolut
DS200412-1963
2003
Jenner, G.A.Tappe, S., Foley, S.F., Jenner, G.A., Ryan, B.,Besserer, D., Kjarsgaard, B.A.Ultramafic lamprophyre dykes from Labrador and New Quebec: mineralogy and geochemistry.8 IKC Program, Session 7, AbstractCanada, Quebec, LabradorKimberlite petrogenesis
DS200512-1071
2005
Jenner, G.A.Tappe, S., Foley, S.F., Jenner, G.A., Kjarsgaard, B.A.Integrating ultramafic lamprophyres into the IUGS classification of igneous rocks: rationale and implications.Journal of Petrology, Vol. 46, 9, Sept. pp. 1893-1900.Classification - lamprophyres
DS200612-1411
2006
Jenner, G.A.Tappe, S., Foley, S.F., Jenner, G.A., Heaman, L.M., Kjarsgaard, B.A., Romer,R.L., Stracke, A., Joyce, HoefsGenesis of ultramafic lamprophyres and carbonatites at Aillik Bay, Labrador: a consequence of incipient lithospheric thinning beneath the North Atlantic CratonJournal of Petrology, Vol. 47,7, pp. 1261-1315.Canada, LabradorCarbonatite
DS200712-1068
2007
Jenner, G.A.Tappe, S., Foley, S.F., Heaman, L.M., Romer, R.E., Stracke, A., Kjarsgaard, B.A., Jenner, G.A.Interactions between carbonate magmas and MARID metasomes: the case of Diamondiferous aillikites from the Torngat Mountains, Canada.Plates, Plumes, and Paradigms, 1p. abstract p. A1003.Canada, LabradorAillikite, magmatism
DS200812-1152
2008
Jenner, G.A.Tappe, S., Foley, S.F., Kjarsgaard, B.A, Romer, R.L., Heaman, L.M., Stracke, A., Jenner, G.A.Origin of Diamondiferous Torngat ultramafic lamprophyres and the role of multiple MARID type and carbonatitic vein metasomatized cratonic mantle ...9IKC.com, 3p. extended abstractCanada, Quebec, LabradorGenesis of SiO2 poor potassic melts
DS200812-1153
2008
Jenner, G.A.Tappe, S., Foley, S.F., Kjarsgaard, B.A., Romer, R.L., Heaman, L.M., Stracke, A., Jenner, G.A.Between carbonatite and lamproite - Diamondiferous Torngat ultramafic lamprohyres formed by carbonate fluxed melting of cratonic Marid type metasomes.Geochimica et Cosmochimica Acta, Vol. 72, 13, pp. 3258-3286.Canada, Labrador, QuebecTorngat
DS1992-0782
1992
Jennings, C.Jennings, C.Diavik projectNorthwest Territories Geoscience Forum held November 25, 26th. 1992, AbstractNorthwest TerritoriesExploration overview, Project - Diavik
DS1992-0783
1992
Jennings, C.Jennings, C.Exploration for diamonds in Canada with special reference to OntarioOntario Geological Survey Mineral Development Forum - talk given December, Abstract onlyOntarioNews item, SouthernEra
DS1993-0745
1993
Jennings, C.Jennings, C.Comments on Paul Sarnoff's Gold Stocks Advisory Report on diamonds.Jennings commentary, Handout at Las Vegas Investment Meeting, 4pGlobalDiamond investment stratgey, Comments by Jennings on Sarnoff
DS1993-0746
1993
Jennings, C.Jennings, C.Report on uranium-lead (U-Pb) (U-Pb) perovskite dating of northwest Territories kimberliteNorthwest Territories Geoscience Forum preprint, 1p.Northwest TerritoriesNews item, SouthernEra Resources Inc.
DS1993-0747
1993
Jennings, C.Jennings, C., Barker, L.Update on Southern Era exploration 1993Northwest Territories Exploration Overview for 1993, November pp. 37-38.Northwest TerritoriesCompany activities, Overview
DS1999-0337
1999
Jennings, C.Jennings, C.The little company that could and did.... Southern Era Resources IncProspectors and Developers Association of Canada (PDAC) abstract volume, p. 9.South Africa, Northwest Territories, Brazil, BotswanaOverview
DS200712-1082
2007
Jennings, C.Thorleifson, L.H., Harris, K.L., Hobbs, H.C., Jennings, C., Knaeble, Lively, Lusar, MeyerTill geochemical and indicator mineral reconnaissance of Minesota.Minnesota Geological Survey, Open File, 07-01, 512p. ( 7p.summary on line)United States, MinnesotaGeochemistry
DS1992-1379
1992
Jennings, C. Chairmen.Sheahan, P.A., Jennings, C. Chairmen.Diamond session: speakers Mitchell, Janse, Lehnert-Thiel, Gent, Jennings. Video cassette ( 2 in total)Resource Media, 2 tapes total cost $ 65.00 for tapesGlobalProspectors and Developers Session talks April 1, 1992, Good quality reproduction of talks, slides
DS1994-0843
1994
Jennings, C.H.Jennings, C.H.One step closer to the sparkle - review of diamond developments and possible economics of diamond mining in Canada's Northwest territories.Prospectors and Developers Association of Canada (PDAC) Annual Meeting March 6-9th. held Toronto, Ontario, Final program abstract volume, p. 44.Northwest TerritoriesEconomics, Diamond mine profile
DS1960-0683
1966
Jennings, C.M.H.Jennings, C.M.H.Report on a Geophysical Survey Carried Out in the Moroba Area, Kgatleng, in an Attempt to Delineate a Kimberlite Pipe.Botswana Geological Survey, (UNPUBL.)BotswanaGeophysics, Kimberlite
DS1970-0105
1970
Jennings, C.M.H.Jennings, C.M.H.The Discovery of Diamonds in BotswanaSouth African Journal of Science, Vol. 66, No. 8, PP. 233-234.BotswanaKimberlite, Orapa, History
DS1990-0761
1990
Jennings, C.M.H.Jennings, C.M.H.Exploration for Diamondiferous kimberlites and lamproitesModern Exploration Techniques, editors L.S. Beck, C.T. Harper, Saskatchewan, pp. 139-148Canada, United StatesOverview, Exploration techniques
DS1991-0336
1991
Jennings, C.M.H.Daniels, L.R.M., Jennings, C.M.H., Lee, F.E., Blaine, J.L.The geology of the M1 kimberlite, southern BotswanaProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 58-59BotswanaExploration, Kimberlite
DS1992-0784
1992
Jennings, C.M.H.Jennings, C.M.H.Diamonds in the Canadian ShieldMan. Geological Survey Convention '92, p. abstractManitobaNews item, Exploration
DS1993-0748
1993
Jennings, C.M.H.Jennings, C.M.H.Diamonds in the Lac de Gras area, Northwest Territories, CanadaMid-continent diamonds Geological Association of Canada (GAC)-Mineralogical Association of Canada (MAC) Symposium ABSTRACT volume, held Edmonton May, pp. 95-99Northwest TerritoriesDiamond exploration Program
DS1994-0371
1994
Jennings, C.M.H.Daniels, L.R.M., Jennings, C.M.H., Lee, J.E., Blaine, J.L., Billington, F.R.The geology of crater volcanics and sediments associated with the M1kimberlite, southwest Botswana.Proceedings of Fifth International Kimberlite Conference, Vol. 1, pp. 129-139.BotswanaKimberlite, Deposit -M1
DS1995-0883
1995
Jennings, C.M.H.Jennings, C.M.H.The exploration context for diamondsJournal of Geochemical Exploration, Vol. 52, pp. 113-124.GlobalDiamond exploration, production charts, pipes, grades, Area selection
DS200912-0431
2009
Jennings, C.M.H.Lee, J.E., Jennings, C.M.H., Blaine, J.L.The GOPE 25 kimberlite discovery, Botswana, predicated on four ilmenite grains from reconnaissance soil samples: a case history.Explore, No. 143, June pp. 1-7.Africa, BotswanaCase history - GOPE 25
DS2000-0446
2000
Jennings, C.M.J.Jennings, C.M.J.Canada D2K... Diamondiferous kimberlitesGeological Association of Canada (GAC)/Mineralogical Association of Canada (MAC) Calgary May 2000, 4p.Northwest Territories, Ontario, Saskatchewan, QuebecExploration, discoveries, techniques
DS1995-0884
1995
Jennings, C.T.Jennings, C.T., Barker, L.A.Three steps forward, one step backProspectors and Developers Association of Canada (PDAC) Annual Meeting, p. 59-60. abstractNorthwest TerritoriesReview
DS1998-0695
1998
Jennings, D.Jennings, D.Insuring project risksThe Canadian Institute of Mining, Metallurgy and Petroleum (CIM)/MIGA Conference Montreal May, 11p. slide overviews no textGlobalEconomics, discoveries, reserves, Risks, insurance
DS1960-1136
1969
Jennings, D.S.Jennings, D.S., Mitchell, R.H.An Estimate of the Temperature of Intrusion of Carbonatite At the Fen Complex, Southern Norway.Lithos, Vol. 2, PP. 167-169.Norway, ScandinaviaBlank
DS201610-1875
2016
Jennings, E.S.Jennings, E.S., Gibson, S.A., Maclennan, J., Heinonen, J.S.Deep mixing of mantle melts beneath continental flood basalt provinces: constraints from olivine hosted melt inclusions in primitive magmas. Etendeka and KarooGeochimica et Cosmochimica Acta, in press availableAfrica, NamibiaPicrite, ferroPicrite

Abstract: We present major and trace element compositions of 154 re-homogenised olivine-hosted melt inclusions found in primitive rocks (picrites and ferropicrites) from the Mesozoic Paraná-Etendeka and Karoo Continental Flood Basalt (CFB) provinces. The major element compositions of the melt inclusions, especially their Fe/Mg ratios, are variable and erratic, and attributed to the re-homogenisation process during sample preparation. In contrast, the trace element compositions of both the picrite and ferropicrite olivine-hosted melt inclusions are remarkably uniform and closely reflect those of the host whole-rocks, except in a small subset affected by hydrothermal alteration. The Paraná-Etendeka picrites and ferropicrites are petrogenetically related to the more evolved and voluminous flood basalts, and so we propose that compositional homogeneity at the melt inclusion scale implies that the CFB parental mantle melts were well mixed prior to extensive crystallisation. The incompatible trace element homogeneity of olivine-hosted melt inclusions in Paraná-Etendeka and Karoo near primitive magmatic rocks has also been identified in other CFB provinces and contrasts with findings from studies of basalts from mid-ocean ridges (e.g. Iceland and FAMOUS on the Mid Atlantic Ridge), where heterogeneity of incompatible trace elements in olivine-hosted melt inclusions is much more pronounced. We suggest that the low variability in incompatible trace element contents of olivine-hosted melt inclusions in near-primitive CFB rocks, and also ocean island basalts associated with moderately thick lithosphere (e.g. Hawaii, Galápagos, Samoa) may reflect mixing along their longer transport pathways during ascent and/or a temperature contrast between the liquidus and the liquid when it arrives in the crust. These thermal paths promote mixing of mantle melts prior to their entrapment by growing olivine crystals in crustal magma chambers. Olivine-hosted melt inclusions of ferropicrites from the Paraná-Etendeka and Karoo CFB have the least variable compositions of all global melt inclusion suites, which may be a function of their unusually deep origin and low viscosity.
DS201611-2115
2016
Jennings, E.S.Jennings, E.S., Gibson, S.A., Maclennan, J., Heinonen, J.S.Deep mantle melts beneath continental flood basalt provinces: constraints from olivine hosted melt inclusions in primitive magmas.Geochimica et Cosmochimica Acta, Vol. 196, pp. 36-57.Africa, Namibia, AngolaParan-Etendeka, Karoo

Abstract: We present major and trace element compositions of 154 re-homogenised olivine-hosted melt inclusions found in primitive rocks (picrites and ferropicrites) from the Mesozoic Parana ´-Etendeka and Karoo Continental Flood Basalt (CFB) provinces. The major element compositions of the melt inclusions, especially their Fe/Mg ratios, are variable and erratic, and attributed to the re-homogenisation process during sample preparation. In contrast, the trace element compositions of both the picrite and ferropicrite olivine-hosted melt inclusions are remarkably uniform and closely re?ect those of the host whole-rocks, except in a small subset a?ected by hydrothermal alteration. The Parana ´-Etendeka picrites and ferropicrites are petrogenet- ically related to the more evolved and voluminous ?ood basalts, and so we propose that compositional homogeneity at the melt inclusion scale implies that the CFB parental mantle melts were well mixed prior to extensive crystallisation. The incompatible trace element homogeneity of olivine-hosted melt inclusions in Parana ´-Etendeka and Karoo primitive magmatic rocks has also been identi?ed in other CFB provinces and contrasts with ?ndings from studies of basalts from mid- ocean ridges (e.g. Iceland and FAMOUS on the Mid Atlantic Ridge), where heterogeneity of incompatible trace elements in olivine-hosted melt inclusions is more pronounced. We suggest that the low variability in incompatible trace element contents of olivine-hosted melt inclusions in near-primitive CFB rocks, and also ocean island basalts associated with moderately thick lithosphere (e.g. Hawaii, Gala ´pagos, Samoa), may re?ect mixing along their longer transport pathways during ascent and/or a temperature contrast between the liquidus and the liquid when it arrives in the crust. These thermal paths promote mixing of mantle melts prior to their entrapment by growing olivine crystals in crustal magma chambers. Olivine-hosted melt inclusions of ferropicrites from the Parana ´-Etendeka and Karoo CFB have the least variable compositions of all global melt inclusion suites, which may be a function of their unusually deep origin and low viscosity.
DS201702-0218
2016
Jennings, E.S.Jennings, E.S., Holland, T.J.B., Shorttle, O., Gibson, S.The composition of melts from a heterogeneous mantle and origin of ferropicrite: application of a thermodynamic model.Journal of Petrology, In press available 22p.MantleEclogite, melting

Abstract: Evidence for chemical and lithological heterogeneity in the Earth’s convecting mantle is widely acknowledged, yet the major element signature imparted on mantle melts by this heterogeneity is still poorly resolved. In this study, a recent thermodynamic melting model is tested on a range of compositions that correspond to potential mantle lithologies (harzburgitic to pyroxenitic), to demonstrate its applicability over this compositional range, in particular for pyroxenite melting. Our results show that, despite the model’s calibration in peridotitic systems, it effectively reproduces experimental partial melt compositions for both Si-deficient and Si-excess pyroxenites. Importantly, the model accurately predicts the presence of a free silica phase at high pressures in Si-excess pyroxenites, indicating the activation of the pyroxene-garnet thermal divide. This thermal divide has a dominant control on solidus temperature, melt productivity and partial melt composition. The model is used to make new inferences on the link between mantle composition and melting behaviour. In silica-deficient and low-pressure (olivine-bearing) lithologies, melt composition is not very sensitive to source composition. Linearly varying the source composition between peridotite and basaltic pyroxenite, we find that the concentration of oxides in the melt tends to be buffered by the increased stability of more fusible phases, causing partial melts of even highly fertile lithologies to be similar to those of peridotite. An exception to this behaviour is FeO, which is elevated in partial melts of silica-deficient pyroxenite even if the bulk composition does not have a high FeO content relative to peridotite. Melt Al2O3 and MgO vary predominantly as a function of melting depth rather than bulk composition. We have applied the thermodynamic model to test the hypothesis that Fe-rich mantle melts such as ferropicrites are derived by partial melting of Si-deficient pyroxenite at elevated mantle potential temperatures. We show that the conspicuously high FeO in ferropicrites at a given MgO content does not require a high-Fe mantle source and is indeed best matched by model results involving around 0-20% melting of silica-deficient pyroxenite. A pyroxenite source lithology also accounts for the low CaO content of ferropicrites, whereas their characteristic low Al2O3 is a function of their high pressure of formation. Phanerozoic ferropicrites are exclusively located in continental flood basalt (CFB) provinces and this model of formation confirms that lithological heterogeneity (perhaps recycled oceanic crust) is present in CFB mantle sources.
DS201704-0629
2017
Jennings, E.S.Jennings, E.S., Holland, T.J.B., Maclennan, J., Gibson, S.A.The composition of melts from a heterogeneous mantle and the origin of ferropicrite: application of a thermodynamic model.Journal of Petrology, Vol. 57, 11-12, pp. 2289-2310.MantleGeochemistry
DS201605-0851
2016
Jennings, H.Jennings, H., Schodde, R.From mineral discovery to project delivery.SEG Newsletter, No. 105, Apr. pp. 1, 20-24.TechnologyExploration
DS1960-0844
1967
Jennings, I.B.Jennings, I.B., Noldart, A.J., Williams, E.Geology and Mineral Resources of TasmaniaTasmania Geological Survey Bulletin., No. 50, P. 89.Australia, TasmaniaDiamond
DS1970-0174
1970
Jennings, J.E.Piteau, D.R., Jennings, J.E.The Effects of Plan Geometry on the Stability of Natural Slopes in Rock in the Kimberley Area of South Africa.International CONGRESS SOC. ROCK MECHANICS Proceedings, Vol. 3, PP. 289-295.South AfricaMining
DS1987-0319
1987
Jennings, M.Jennings, M.The production and uses of industrial diamondMet. Material, Vol. 3, No. 9, pp. 525-531GlobalReview
DS202108-1291
2021
Jennings, S.J.A.Jennings, S.J.A., Hambrey, M.J.Structures and deformation in glaciers and ice sheetsReviews of Geophysics, e2021RG000743 1Globalgeomorphology

Abstract: The major structures in the long, narrow tongue of a sub-polar valley glacier are described: namely, longitudinal foliation, crevasses, clear-ice layers related to crevasses, debris-rich layers (frequently referred to as thrust or shear planes in the past), and folds. The foliation is vertical, is as well-developed in the centre of the glacier as at the margins, and does not, apparently, form perpendicular to the principal compressive strain-rate axis, nor exactly parallel to a line of maximum shearing strain-rate, although it sometimes approximately coincides with the latter. The intensity of foliation development is not related to the magnitude of the strain-rates, but the structure consistently lies parallel to flow lines through the glacier. There is no critical extending strain-rate, as such, associated with the development of new crevasses. Some crevasses have formed where the principal extending strain-rate is as low as 0.004 a-1 while, in other areas, extending strain-rates of 0.163 a-1 have not always resulted in fracturing. Prominent clear-ice layers, referred to as crevasse traces as displayed at the glacier surface, have formed in crevasse belts parallel to the main fracture directions. These are interpreted either as tensional veins or as the result of the freezing of water in crevasses. Extension parallel to the layering occurs during flow and, near the snout, the surface dip decreases rapidly. The fact that the crevasse traces can be followed to the snout implies that fracture occurs almost to the bottom of the glacier in the source area of the traces. Near the snout, debris-rich layers have developed parallel to the crevasse traces; frequently these are marked by prominent ridge-like ice-cored moraines. It is suggested that these structures are formed by a combination of basal freezing and thrusting. Isoclinal and tight similar folds on all scales are present. Some may be formed by the passive deformation of clear-ice layers as a result of differential flow; others may arise from the lateral compression of the original stratification in areas where ice flow becomes constricted by the narrowing of the valley. An axial plane foliation sometimes is associated with these folds.
DS1960-0534
1965
Jenningsm c.m.h.Crockett, R.N., Jenningsm c.m.h.Geology of Part of the Okwa Valley, Western BechuanalandGeological Survey Bechuanaland Protectorate, 1961-1962, PP. 101-113.BotswanaGeology
DS201412-0429
2014
Jenny, P.Jenny, P.Radiogenic isotope constraints on lithospheric assimilation by sublithospheric melts in the generation of southern African kimberlite megacrysts: a comparsion of on and off craton megacryst suites.ima2014.co.za, AbstractAfrica, southern AfricaCraton, on-off
DS2000-0447
2000
Jensen, B.B.Jensen, B.B.Partitioning of elements in sector zoned clinopyroxenesMineralogical Magazine, Vol. 64, No. 4, Aug. 1, pp.725-8.GlobalCarbonatite
DS2003-0424
2003
Jensen, B.K.Frei, R., Jensen, B.K.Re Os and Sm Nd isotope and REE systematics on ultramafic rocks and pillow basaltsChemical Geology, Vol. 196, No. 1-4, pp. 163-191.GreenlandGeochronology
DS200412-0579
2003
Jensen, B.K.Frei, R., Jensen, B.K.Re Os and Sm Nd isotope and REE systematics on ultramafic rocks and pillow basalts from the Earth's oldest oceanic crustal fragmChemical Geology, Vol. 196, no. 1-4, pp. 163-191.Europe, GreenlandGeochronology
DS1900-0672
1908
Jensen, H.I.Jensen, H.I.The Geology of the Nandewar MountainsNew South Wales Linn. Soc. Proceedings, Vol. 32, PP. 842-914.Australia, New South WalesKimberlite, Diamond
DS1950-0331
1957
Jensen, K.D.Jensen, K.D.Vorkommen und Genesis der Zentral Indischen DiamantenNeues Jahrbuch f?r Mineralogie, No. 3, PP. 49-67.IndiaDiamond Occurrences, Genesis
DS1989-1546
1989
Jensen, L.S.Veizer, J., Hoefs, J., Ridler, R.H., Jensen, L.S., Lowe, D.R.Geochemistry of Precambrian carbonates. 1. Archean hydrothermal systemsGeochimica et Cosmochimica Acta, Vol. 53, No. 4, April pp. 845-858. Database # 17926GlobalGeochemistry, Precambrian
DS2001-0533
2001
Jensen, M.Jensen, M.An update on the QP status in CanadaThe Canadian Mining and Metallurgical Bulletin (CIM Bulletin) ., Vol. 94, No. 1047, Feb. p. 33.CanadaLegal, Laws - regulatory
DS2001-0534
2001
Jensen, M.Jensen, M.Report card on the mining standards task force recommendation implementatioThe Canadian Mining and Metallurgical Bulletin (CIM Bulletin) ., Vol. 94, No. 1047, Feb. pp. 31-32.CanadaLegal, Laws - regulatory
DS1991-0605
1991
Jensen, O.Gregotski, M.E., Jensen, O., Arkani-Hamed, J.Fractal stochastic modeling of aeromagnetic dataGeophysics, Vol. 56, No. 11, November pp. 1706-1715Alberta, OntarioGeophysics, Athabaska Basin, Kirkland Lake
DS1999-0303
1999
Jensen, S.Helmstaedt, H.H., Olesen, H.K., Jensen, S., SchonwandtThe diamond potential of the northern margin of the North Atlantic Cratonin West Greenland.North Atlantic Mineral Symposium, Sept., abstracts pp. 169-70.Greenland, Labrador, Ungava, QuebecExploration - brief review, Craton
DS201503-0152
2015
Jensen, S.Jensen, S.Diamonds beneath the Popigai crater - northern Russia.Denver Geophysical Society, The Record, No. 3, Feb. pp. 3-5.RussiaPopigai - rehash
DS2002-0779
2002
Jensen, S.L.Jensen, S.L., Thybo, H.Moho topography and lower crustal wide angle reflectivity around the TESZ in southern Scandinavia and northeastern Europe.Tectonophysics, Vol. 360, 1-4, pp. 187-213.Europe, ScandinaviaGeophysics - seismics
DS1998-0696
1998
Jensen, S.M.Jensen, S.M.Tertiary mineralization and magmatism, East Greenland: lead isotope evidence for remobilization of cont. crustChemical Geology, Vol. 150, No. 1-2, Aug. 24, pp. 119-146.GreenlandMagmatism, Geochronology
DS1998-0783
1998
Jensen, S.M.Kontak, D.J., Jensen, S.M., Dostal, ArchibaldPetrology of Late Cretaceous (CA 90 Ma) lamprophyric dykes from NorthGreenland.Geological Association of Canada (GAC)/Mineralogical Association of Canada (MAC) Abstract Volume, p. A94. abstract.GreenlandDikes - lamprophyre, Petrography
DS1999-0524
1999
Jensen, S.M.Olsen, H.K., Jensen, S.M., Schonwandt, H.K., HelmstaedtReview of diamond exploration in GreenlandNorth Atlantic Mineral Symposium, Sept., abstracts pp. 166-8.Greenland, Labrador, Ungava, QuebecExploration - brief review, History
DS1999-0711
1999
Jensen, S.M.Steenfelt, A., Jensen, S.M., Larsen, L.M., Stendal, H.Diamond exploration in southern West GreenlandAssocation of Exploration Geologists (AEG) 19th. Diamond Exploration Methods Case Histories, pp. 76-84.GreenlandKimberlite - petrology, Sisimuit, Sarfartoq, Maniitsoq
DS2001-0622
2001
Jensen, S.M.Kontak, D.J., Jensen, S.M., Dostal, Archibald, KyserCretaceous mafic dike swarm, Peary Land, northern most Greenland: geochronology and petrology.Canadian Mineralogist, Vol. 39, No. 4, Aug. pp. 997-1020.GreenlandLamprophyres, Mantle plume
DS2002-0780
2002
Jensen, S.M.Jensen, S.M., Hanson, H., Secher, K., Steenfelt, A., Schjoth, F., Rasmussen, T.M.Kimberlites and other ultramafic alkaline rocks in the Sismiut-Kangerfussuaq region, southwest Greenland.Geology of Greenland Survey Bulletin, No. 191, pp. 57-66.GreenlandDistribution and magnetic signatures of dykes
DS2003-0653
2003
Jensen, S.M.Jensen, S.M., Lind, M., Rasmussen, T.M., Schjoth, F., Secher, K.Greenland exploration dat a on DVD - the guide to future kimberlite targets in theDanmarks og Gronlands Geologiske Undersagelse Rapport, 2003/21, 50p. plus 1 DVD $100.US www.geus.dkGreenlandMineral analyses, samples, drill logs
DS2003-0654
2003
Jensen, S.M.Jensen, S.M., Lind, M., Rasmussen, T.M., Schjoth, F., Secher, K.Diamond exploration dat a from West GreenlandDanmarks OG Gronlands Geologiske Undersogelse, Rapport 2003-21, 50p.GreenlandBlank
DS2003-0655
2003
Jensen, S.M.Jensen, S.M., Secher, K., Rasmussen, T.M., Tukiainen, T., Krebs, J.D., Schifth, F.Distribution and magnetic signatures of kimberlitic rocks in the Sarfartoq region8 Ikc Www.venuewest.com/8ikc/program.htm, Session 8, POSTER abstractGreenlandBlank
DS200412-0912
2003
Jensen, S.M.Jensen, S.M., Lind, M., Rasmussen, T.M., Schjoth, F., Secher, K.Greenland exploration dat a on DVD - the guide to future kimberlite targets in the compilation Diamond Exploration dat a from WestDanmarks OG Gronlands Geologiske Undersogelse, 2003/21, 50p. plus 1 DVD $100.US www.geus.dkEurope, GreenlandMaps, tables, data from assessment reports, GIS, Pdf Mineral analyses, samples, drill logs
DS200412-0913
2003
Jensen, S.M.Jensen, S.M., Lind, M., Rasmussen, T.M., Schjoth, F., Secher, K.Diamond exploration dat a from West Greenland.Danmarks OG Gronlands Geologiske Undersogelse, Rapport 2003-21, 50p.Europe, GreenlandOverview of available company data, analyses
DS200412-0914
2003
Jensen, S.M.Jensen, S.M., Secher, K., Rasmussen, T.M., Tukiainen, T., Krebs, J.D., Schifth, F.Distribution and magnetic signatures of kimberlitic rocks in the Sarfartoq region, southern West Greenland.8 IKC Program, Session 8, POSTER abstractEurope, GreenlandDiamond exploration
DS200812-0796
2008
Jensen, S.M.Nielsen, T.F.D., Jensen, S.M., Secher, K., Sand, K.K.Regional and temporal variations in the magmatism of the diamond province of southern west Greenland.9IKC.com, 3p. extended abstractEurope, GreenlandDykes - Sisimiut, Sarfartoq
DS200812-1259
2008
Jensen, S.M.Wittig, N., Pearson, D.G., Webb, M., Ottley, C.J., Irvine, G.J., Kopylova, M., Jensen, S.M., Nowell, G.M.Origin of cratonic lithospheric mantle roots: a geochemical study of peridotites from the North Atlantic Craton, West Greenland.Earth and Planetary Science Letters, In press available, 83p.Europe, GreenlandGeochemistry
DS200812-1260
2008
Jensen, S.M.Wittig, N., Pearson, D.G., Webb, M., Ottley, C.J., Irvine, G.J., Kopylova, M., Jensen, S.M., Nowell, G.M.Origin of cratonic lithospheric mantle roots: a geochemical study of peridotites from the North Atlantic craton, West Greenland.Earth and Planetary Science Letters, Vol. 274, 1-2, pp. 24-33.Europe, GreenlandGeochemistry
DS200812-1261
2008
Jensen, S.M.Wittig, N., Webb, M.,Pearson, D.G., Dale, C.W., Ottley, C.J., Luguet, A., Jensen, S.M.Lithosphere stabilization ages beneath sw Greenland.Goldschmidt Conference 2008, Abstract p.A1030.Europe, GreenlandNorth Atlantic Craton, kimberlites
DS200912-0535
2009
Jensen, S.M.Nielsen, T.F.D., Jensen, S.M., Secher, K., Sand, K.K.Distribution of kimberlite and aillikite in the diamond province of southern West Greenland: a regional perspective based on groundmass mineral chemistry and bulk compositions.Lithos, In press - available 45p.Europe, GreenlandGeochemistry
DS200912-0681
2009
Jensen, S.M.Secher, K., Heaman, L.M., Nielsen, T.F.D., Jensen, S.M., Schjeth, F., Creaser, R.A.Timing of kimberlite, carbonatite and ultramafic lamprophyric emplacement in the alkaline province located at 64 - 67 N in southern West Greenland.Lithos, In press available, 21p.Europe, GreenlandGeochronology
DS200912-0733
2009
Jensen, S.M.Steenfelt, A., Jensen, S.M., Nielsen, T.F.D., Sand, K.K., Secher, K.Diamonds and lithospheric mantle properties in the neo-proterzoic igneous province of southern West Greenland. ( Garnet Lake area).Geological Survey of Denmark and Greenland, Bulletin 17, pp. 65-68.Europe, GreenlandDiamond exploration - brief overview
DS201012-0755
2009
Jensen, S.M.Steenfelt, A., Jensen, S.M., Nielsen, T.F.D., Sand, K.K.Provinces of ultramafic lamprophyre dykes, kimberlite dykes and carbonatite in West Greenland characterised by minerals and chemical components in surface media.Lithos, Vol. 112 S pp. 116-123.Europe, GreenlandGeochemistry
DS201012-0854
2010
Jensen, S.M.Wittig, N., Webb, M., Pearson, D.G., Dale, C.W., Ottley, C.J., Hutchison, M., Jensen, S.M., Luget, A.Formation of the North Atlantic craton: timing and mechanisms constrained from Re-Os isotope and PGE dat a of peridotite xenoliths from S.W. Greenland.Chemical Geology, Vol. 276, 3-4, pp. 166-187.Europe, GreenlandCraton
DS201012-0855
2010
Jensen, S.M.Wittig, N., Webb, M., Pearson, D.G., Dale, C.W., Ottley, C.J., Hutchison, M., Jensen, S.M., Luget, A.Formation of the North Atlantic craton: timing and mechanisms constrained from Re-Os isotope and PGE dat a of peridotite xenoliths from S.W. Greenland.Chemical Geology, Vol. 276, 3-4, pp. 166-187.Europe, GreenlandCraton
DS201810-2372
2018
Jeon, H.Rielli A., Tomkins, A.G., Nebel, O., Raveggi, M., Jeon, H., Martin, L., Laure, A., Janaina, N.Sulfur isotope and PGE systematics of metasomatised mantle wedge.Earth and Planetary Science Letters, Vol. 497, 1, pp. 181-192.Mantlemetasomatism

Abstract: At convergent margins fluids liberated from subducting slabs metasomatise the overlying mantle wedge, enriching it in volatiles, incompatible elements and possibly ore-forming metals. Despite the genetic link between this process, the genesis of arc magmas, and formation of porphyry Cu-Au deposits, there is currently little understanding of the behaviour of chalcophile and siderophile elements during subduction-related mantle metasomatism. In this study, we report sulfur isotopic compositions and PGE concentrations of sulfides in a suite of garnet peridotites from the Western Gneiss Region of Norway, sampling mantle wedge from ?100 to ?250 km depth. Sulfides hosted in metasomatised samples have deviated from typical mantle values, ranging between ?10.0 and +5.4‰, indicating derivation of sulfur from subducted crust. Sulfides in pervasively metasomatised samples have atypical PGE signatures, with strong enrichment in Os and Ru relative to Ir, whereas channelised fluid flow produced sulfides extremely enriched in Pd, up to 700 times the concentration found in non-metasomatised samples. These signatures are reconcilable with a high oxidation state of the metasomatising agents and demonstrate that subduction can recycle chalcophile and siderophile elements into and within the mantle, along with sulfur. We further show that because the solubility of Os and Ru in fluids is redox sensitive, and Pd is more soluble than the I-PGE, ratios such as Os/Ir, Ru/Ir plotted against Pd/Ir can be used to trace the metasomatic oxidation of mantle samples, mantle-derived magmas and porphyry Cu±Au deposits. This geochemical insight is used to show that Au-rich porphyry Cu deposits are derived from more oxidised mantle wedge than Au-poor porphyry deposits.
DS201412-1024
2014
Jeong, J.S.Zhang, L., Meng, Y., Yang, W.,Wang, L., Mao, W.L., Zeng, Q-S., Jeong, J.S., Wagner, A.J., Mkhoyan, K.A., Liu, W., Xu, R., Mao, H-K.Disproportionation of (Mg,Fe) SiO3 perovskite in Earth's deep lower mantle.Science, Vol. 344, no. 6186, pp. 877-882.MantlePerovskite
DS2000-0994
2000
Jephcoat, A.Wain, A., Waters, D., Jephcoat, A., Olijnk, H.The high pressure to ultrahigh pressure eclogite transition in the Western Gneiss region, Norway.European Journal of Mineralogy, No. 3, pp. 667-88.NorwayEclogite, ultra high pressure (UHP)
DS2001-0535
2001
Jephcoat, A.Jephcoat, A., Refson, K.Core beliefs. Iron in inner coreNature, Vol. 413, Sept. 6, pp. 27-28.MantleInner core, geochemistry
DS2002-0193
2002
Jephcoat, A.P.Bouhild, M.A., Jephcoat, A.P.Metal silicate interactions at high pressure and temperature in the diamond anvil cell18th. International Mineralogical Association Sept. 1-6, Edinburgh, abstract p.77.MantleUHP mineralogy, Redox conditions
DS200712-0553
2006
Jephcoat, A.P.Kleppe, A.K., Jephcoat, A.P.Raman spectroscopic studies of hydrous and nominally anhydrous deep mantle phases.American Geophysical Union, Geophysical Monograph, No. 168, pp. 69-94.MantleWater
DS200812-0520
2008
Jephcoat, A.P.Jephcoat, A.P., Bouhifd, M.A., Porcelli, D.Metal silicate element partitioning at ultrahigh pressures: He to I.Goldschmidt Conference 2008, Abstract p.A427.TechnologyLHDAC
DS201610-1891
2016
Jephcoat, A.P.Nestola, F., Alvaro, M., Casati, M.N., Wilhelm, H., Kleppe, A.K., Jephcoat, A.P., Domeneghetti, M.C., Harris, J.W.Source assemblage types for cratonic diamonds from x-ray synchroton diffraction.Lithos, in press available 5p.RussiaDeposit - Udachnaya
DS2002-1237
2002
JepsenPedersen, S. Craig, Upton, TapaniRamo, Jepsen, KalsbeekPaleoproterozoic (1740 Ma) rift related volcanism in the Hekla Sund region, field occurrence, geochemistryPrecambrian Research, Vol. 114, No. 3-4, Mar.15, pp.327-46.Greenland, eastern northTectonics
DS1998-0697
1998
Jepsen, A.F.Jepsen, A.F.Mineral exploration and mining principles: an introductionProspectors and Developers Association of Canada (PDAC) Fundamentals of Exploration and Mining, pp. 1-24GlobalMineral exploration, Mining principles
DS200512-1110
2005
Jepsen, H.F.Upton, B.G.J., Ramo, O.T., Heaman, L.M., Blichert-Toft, J., Kalsbeek, F., Barry, T.L., Jepsen, H.F.The Mesoproterozoic Zig-Zag Dal basalts and associated intrusions of eastern North Greenland: mantle plume lithosphere interaction.Contributions to Mineralogy and Petrology, Vol. 149, 1, pp. 40-56.Europe, GreenlandTectonics
DS201904-0715
2019
Jepson, G.Armistead, S.E., Collins, A.S., Redaa, A., Gilbert, S., Jepson, G., Gillespie, J., Blades, M.L., Foden, J.D., Razakamana, T.Structural evolution and medium temperature thermochronology of central Madagascar: implications for Gondwana amalgamation.Journal of the Geological Society of London, in press available 25p.Africa, Madagascarthermochronology

Abstract: Madagascar occupied an important place in the amalgamation of Gondwana, and preserves a record of several Neoproterozoic events that can be linked to orogenesis of the East African Orogen. We integrate remote sensing and field data to unravel complex deformation in the Ikalamavony and Itremo domains of central Madagascar. The deformation sequence comprises a gneissic foliation (S1), followed by south to south-west directed, tight to isoclinal, recumbent folding (D2). These are overprinted by north-trending upright folds that formed during a ~E-W shortening event. Together these produced type 1 and type 2 fold interference patterns throughout the Itremo and Ikalamavony domains. Apatite U-Pb and muscovite and biotite Rb-Sr thermochronometers indicate that much of central Madagascar was thermally reset to at least ~500oC at c. 500 Ma. Deformation in west-central Madagascar occurred between c. 750 Ma and c. 550 Ma, and we suggest this deformation formed in response to the c. 650 Ma collision of Azania with Africa along the Vohibory Suture in southwestern Madagascar. In eastern Madagascar, deformation is syn- to post-550 Ma, which formed in response to the final closure of the Mozambique Ocean along the Betsimisaraka Suture that amalgamated Madagascar with the Dharwar Craton of India.
DS201908-1769
2019
Jepson, G.Alessio, B.L., Glorie, S., Collins, A.S., Jourdan, F., Jepson, G., Nixon, A., Siegfried, P.R., Clark, C.The thermo-tectonic evolution of the southern Congo craton margin as determined from apatite and muscovite thermochronology.Tectonophysics, Vol. 766, pp. 398-415.Africa, Zambia, Malawi, Mozambique, Tanzaniacraton

Abstract: The Southern Irumide Belt (SIB) of Zambia consists of predominantly Mesoproterozoic terranes that record a pervasive tectono-metamorphic overprint from collision between the Congo and Kalahari cratons in the final stages of Gondwana amalgamation. This study applies multi-method thermochronology to samples throughout southern Zambia to constrain the post-collisional, Phanerozoic thermo-tectonic evolution of the region. U-Pb apatite and 40Ar/39Ar muscovite data are used to constrain the cooling history of the region following Congo-Kalahari collision, and reveal ages of c. 550-450?Ma. Variations in the recorded cooling ages are interpreted to relate to localised post-tectonic magmatism and the proximity of analysed samples to the Congo-Kalahari suture. Apatite fission track data are used to constrain the low-temperature thermo-tectonic evolution of the region and identify mean central ages of c. 320-300, 210-200 and 120-110?Ma. Thermal modelling of these samples identifies a number of thermal events occurring in the region throughout the Phanerozoic. Carboniferous to Permian-Triassic heating is suggested to relate to the development of Karoo rift basins found throughout central Africa and constrain the timing of sedimentation in the basin. Permian to Jurassic cooling is identified in a number of samples, reflecting exhumation as a result of the Mauritanian-Variscan and Gondwanide orogenies. Subsequent cooling of the majority of samples occurs from the Cretaceous and persists until present, reflecting exhumation in response to larger scale rifting associated with the break-up of Gondwana. Each model reveals a later phase of enhanced cooling beginning at c. 30?Ma that, if not an artefact of modelling, corresponds to the development of the East African Rift System. The obtained thermochronological data elucidate the previously unconstrained thermal evolution of the SIB, and provides a refined regional framework for constraining the tectonic history of central Africa throughout the Phanerozoic.
DS202010-1826
2020
Jepson, G.Armistead, S.E., Collins, A.S., Redaa, A., Jepson, G., Gillespie, J., Gilbert, S., Blades, M.L., Foden, J.D., RazakMnN, T.Structural evolution and medium temperature thermochronology of central Madagascar: implications for Gondwana amalagamation.Journal of the Geological Society, Vol. 177, pp. 784-798.Africa, Madagascargeothermometry

Abstract: Madagascar occupied an important place in the amalgamation of Gondwana and preserves a record of several Neoproterozoic events that are linked to orogenesis of the East African Orogen. In this study, we integrate remote sensing, field data and thermochronology to unravel complex deformation in the Ikalamavony and Itremo domains of central Madagascar. The deformation sequence comprises a gneissic foliation (S1), followed by south- to SW-directed, tight to isoclinal, recumbent folding (D2). These are overprinted by north-trending upright folds that formed during an approximately east-west shortening event (D3). Together these produced type 1 and type 2 fold interference patterns throughout the Itremo and Ikalamavony domains. We show that the Itremo and Ikalamavony domains were deformed together in the same orogenic system, which we interpret as the c. 630 Ma collision of Azania with Africa along the Vohibory Suture in southwestern Madagascar. In eastern Madagascar, deformation is syn- to post-550 Ma, and probably formed in response to final closure of the Mozambique Ocean along the Betsimisaraka Suture that amalgamated Madagascar with the Dharwar Craton of India. Apatite U-Pb and novel laser ablation triple quadrupole inductively coupled plasma mass spectrometry (LA-QQQ-ICP-MS) muscovite and biotite Rb-Sr thermochronology indicates that much of central Madagascar cooled through c. 500°C at c. 500 Ma.
DS200512-1181
2005
Jercinovic, M.J.Williams, M.L., Jercinovic, M.J., Mahan, K., Drumond, G., Flowers, R.M., Davis, W.J.Regional high T metamorphic events in Proterozoic crust of Laurentia: implications of magmatic underplating for regional tectonics crustal evolution.GAC Annual Meeting Halifax May 15-19, Abstract 1p.Canada, Nunavut, Saskatchewan, AlbertaTectonics, Churchill Province
DS1998-1375
1998
JerdeSobolev, V.N., Taylor, L.A., Snyder, Jerde, NealMetasomatism of the mantle beneath Yakutia: a quantitative study of secondary chemistry and mineral..7th International Kimberlite Conference Abstract, pp. 835-7.Russia, YakutiaXenoliths, Deposit - Udachnaya
DS1991-0792
1991
Jerde, E.A.Jerde, E.A.Geochemistry and petrology of hypabyssal rocks associated with The midcontinent Rift, northeastern MinnesotaPh.d. thesis, University of California, Los Angeles, 305pMinnesotaGeochemistry, Midcontinent Rift
DS1991-0793
1991
Jerde, E.A.Jerde, E.A.Magmatic evolution in the midcontinent rift: evidence from hypabyssal rocks from the north shore of Lake SuperiorGeological Society of America Annual Meeting Abstract Volume, Vol. 23, No. 5, San Diego, p. A 44OntarioTectonics, Midcontinent rift
DS1991-0794
1991
Jerde, E.A.Jerde, E.A., Taylor, L.A., Sobolev, N.V., Crozaz, G.Rare earth elements in Diamondiferous eclogites from Yakutia, Siberia:evidence for source region variabilityEos Transactions, Vol. 72, No. 44, October 29, abstract p. 517Russia, Yakutia, SiberiaEclogites, rare earth elements (REE).
DS1992-0785
1992
Jerde, E.A.Jerde, E.A., et al.Peridotite rare earth elements (REE) signatures in eclogites from Yakutia ,Siberia: evidence formelting of a garnet lherzolite parent?Eos, Transactions, Annual Fall Meeting Abstracts, Vol. 73, No. 43, October 27, abstracts p. 656Russia, YakutiaPeridotite, Eclogites
DS1992-0786
1992
Jerde, E.A.Jerde, E.A., Taylor, L.A., Crozaz, G., Sobolev, N.V., Sobolev, V.N.Diamondiferous eclogites from Yakutia Siberia: rare earth element evidence for a range of crustal protolithsGeological Society of America (GSA) Abstracts with programs, 1992 Annual, Vol. 24, No. 7, abstract p. A260Russia, YakutiaEclogites, Diamonds
DS1992-0787
1992
Jerde, E.A.Jerde, E.A., Taylor, L.A., Sobolev, N.V., Crozaz, C.Diamondiferous eclogites from Yakutia, Siberia: comparison with Kaapvaal craton and rare earth element evidence for source region variabilityProceedings of the 29th International Geological Congress. Held Japan August 1992, Vol. 1, abstract p. 179Russia, Yakutia, southern AfricaEclogites, rare earth elements (REE).
DS1993-0462
1993
Jerde, E.A.Fraracci, K.N., Taylor, L.A., Jerde, E.A., Snyder, G.A., ClaytonTwo unusual Diamondiferous eclogite xenoliths from the Mir kimberlite inYakutia, SiberiaGeological Society of America Annual Abstract Volume, Vol. 25, No. 6, p. A445 abstract onlyRussia, Siberia, YakutiaXenoliths -eclogite, Deposit -Mir
DS1993-0749
1993
Jerde, E.A.Jerde, E.A., Taylor, L.A., Crozaz, G., Sobolev, N.V.Exsolution of garnet within clinopyroxene of mantle eclogites - major element and trace-element chemistryContribution to Mineralogy and Petrology, Vol. 114, No. 2, June pp. 148-159MantleEclogites, Geochemistry
DS1993-0750
1993
Jerde, E.A.Jerde, E.A., Taylor, L.A., Crozaz, G., Sobolev, N.V., Sobolev, V.N.Diamondiferous eclogites from Yakutia, Siberia: evidence for a diversity ofprotolithsContribution to Mineralogy and Petrology, Vol. 114, No. 2, June pp. 189-202GlobalEclogites, Udachnaya pipe, chemistry, geobarometry
DS1993-1493
1993
Jerde, E.A.Snyder, G.A., Jerde, E.A., Taylor, L.A., Halliday, A.N., Sobolevneodymium and Strontium isotopes from Diamondiferous eclogites, UdachnayaEarth and Planetary Science Letters, Vol. 118, No. 1-4, July, pp. 91-100.Russia, Siberia, YakutiaGeochronology, Deposit -Udachnaya
DS1993-1494
1993
Jerde, E.A.Snyder, G.A., Jerde, E.A., Taylor, L.A., Sobolev, N.V.Earliest differentiation of the earth's mantle: evidence from the isotopic studies of Diamondiferous eclogites, Yakutia, Siberia, Russia.Geological Society of America Annual Abstract Volume, Vol. 25, No. 6, p. A73 abstract onlyRussia, Yakutia, RussiaGeochronology, Eclogites
DS1993-1495
1993
Jerde, E.A.Snyder, G.A., Taylor, L.A., Jerde, E.A., et al.Petrogenesis of garnet pyroxenite and spinel peridotite xenoliths of the Tell Danun alkali basalt volcano.International Geology Review, Vol. 35, No. 12, Dec. pp. 1104-1120.SyriaXenoliths, Harrat As Shamah area
DS1995-1791
1995
Jerde, E.A.Snyder, G.A., Taylor, L.A., Jerde, E.A., Clayton, MayedaArchean mantle heterogeneity and origin of Diamondiferous eclogites:evidence hydroxyl in garnets.American Mineralogist, Vol. 80, July-Aug. No. 7-8, pp. 799-809.GlobalGeochronology, Eclogites
DS1998-0698
1998
Jerde, E.A.Jerde, E.A.Geochemistry of hypabyssal rocks of the Midcontinent rift system inMinnesota, and implications- magmatic.International Geology Review, Vol. 40, No. 11, Nov. pp. 963-980.MinnesotaKeweenawan magmatic family tree, Tectonics
DS2000-0448
2000
Jerde, E.A.Jerde, E.A.Geochemistry of hypabyssal rocks of the Midcontinent rift system in Minnesota and implications...Snyder, Neal, Ernst, Plan. Petrology and Geochemistry, pp. 92-109.MinnesotaKeweenawan magmatic family tree, Tectonics
DS1860-0147
1871
Jeremejew, P.Jeremejew, P.Vorkommen von Diamanten in Xanthophyllit des OuralsNeues Jahrbuch f?r Mineralogie, RussiaDiamond mineralogy
DS1860-0992
1897
Jeremejew, P.Jeremejew, P.Ueber Einen Neuen Uralschen DiamantVerhand. Russ. K. Min. Gesell., Vol. 34, PP. 59-60.RussiaDiamond Occurrence
DS1860-0993
1897
Jeremejew, P.Jeremejew, P., Yeremeev, P.About the Diamonds from the Transvaal PremierObshch. Vses. Miner. Zap., Vol. 35, PP. 31-32. ALSO: ZEITSCHR. KRYST. (LEIPZIG), Vol. 3Africa, South Africa, TransvaalMineralogy, Alluvial Placers
DS1860-1089
1899
Jeremejew, P.Jeremejew, P., Yeremeev, P.Ueber Boortkrystalle aus TransvaalObshch. Vses. Miner. Zap., Vol. 36, PP. 35-36. ALSO: ZEITSCHR. KRYST. (LEIPZIG), Vol. 3Africa, South Africa, TransvaalBort, Mineralogy
DS1994-1041
1994
Jeremielta, R.A.Litherland, M., Aspden, J.A., Jeremielta, R.A.The metamorphic belts of EcuadorBritish Geological Survey Overseas Memoir, No. 11, approx. $ 140.00EcuadorBook -ad, Metamorphic belts
DS201112-0482
2011
Jerram, D.Jerram, D., Petford, N.The field description of igneous rocks, second edition.Wiley Blackwell, 256p. $ 40.00TechnologyBook - field guide
DS200712-0490
2007
Jerram, D.A.Jerram, D.A., Davidson, J.P.Frontiers in textural and microgeochemical analysis.Elements, Vol. 3, 4, August pp. 235-238.TechnologyGeochemistry
DS200912-0218
2009
Jerram, D.A.Field, M., Gernon, T.M., Mock, A., Walters, A., Sparks, R.S.J., Jerram, D.A.Variations of olivine abundance and grain size in the Snap lake kimberlite intrusion, Northwest Territories, Canada: a possible proxy for diamonds.Lithos, In press available 13p.Canada, Northwest TerritoriesDeposit - Snap Lake
DS200912-0337
2009
Jerram, D.A.Jerram, D.A., Mock, A., Davis, G.R., Field, M., Brown, R.J.3D crystal size distributions: a case study quantifying olivine populations in kimberlites.Lithos, In press - available 30p.Africa, South AfricaDeposit - Venetia, Dutoitspan
DS201812-2823
2018
Jerram, D.A.Jerram, D.A., Sharp, T.H., Torsvik, T.H., Poulson, R., Watton, T.H., Freitag, U., Halton, A., Sherlock, S.C., Malley, J.A.S., Finley, A., Roberge, J., Swart, R., Fabregas, P., Ferreira, C.H., Machado, V.Volcanic constraints on the unzipping of Africa from South America: insights from new geochronological controls alone the Angola margin.Tectonophysics, doi.org/10.1016/ j.tecto.2018.07.027 33p.Africa, Angola, South Americageochronology

Abstract: The breakup of Africa from South America is associated with the emplacement of the Paraná-Etendeka flood basalt province from around 134 Ma and the Tristan da Cunha plume. Yet many additional volcanic events occur that are younger than the main pulse of the Paraná-Etendeka and straddle the rift to drift phases of the main breakup. This contribution reports on new geochronological constraints from the Angolan part of the African Margin. Three coastal and one inland section have been sampled stretching across some 400 Km, with 39Ar/40Ar, U-Pb and Palaeontology used to provide age constraints. Ages from the new data range from ~100 to 81 Ma, with three main events (cr. 100, 91 and 82-81 Ma). Volcanic events are occurring within the Early to Late Cretaceous, along this part of the margin with a general younging towards Namibia. With the constraints of additional age information both onshore and offshore Angola, a clear younging trend at the early stages of rift to drift is recorded in the volcanic events that unzip from North to South. Similar age volcanic events are reported from the Brazilian side of the conjugate margin, and highlight the need to fully incorporate these relatively low volume volcanic pulses into the plate tectonic breakup models of the South Atlantic Margin.
DS201904-0750
2019
Jerram, D.A.Jerram, D.A., Sharp, I.R., Torsvik, T.H., Poulsen, R., Machado, V.Volcanic constraints on the unzipping of Africa from South America: insights from new geochronological controls along the Angola margin.Tectonophysics, in press available 27p.Africa, Angola, South Americageochronology

Abstract: The breakup of Africa from South America is associated with the emplacement of the Paraná-Etendeka flood basalt province from around 134?Ma and the Tristan da Cunha plume. Yet many additional volcanic events occur that are younger than the main pulse of the Paraná-Etendeka and straddle the rift to drift phases of the main breakup. This contribution reports on new geochronological constraints from the Angolan part of the African Margin. Three coastal and one inland section have been sampled stretching across some 400?Km, with 39Ar/40Ar, U-Pb and Palaeontology used to provide age constraints. Ages from the new data range from ~100 to 81?Ma, with three main events (cr. 100, 91 and 82-81?Ma). Volcanic events are occurring within the Early to Late Cretaceous, along this part of the margin with a general younging towards Namibia. With the constraints of additional age information both onshore and offshore Angola, a clear younging trend at the early stages of rift to drift is recorded in the volcanic events that unzip from North to South. Similar age volcanic events are reported from the Brazilian side of the conjugate margin, and highlight the need to fully incorporate these relatively low volume volcanic pulses into the plate tectonic breakup models of the South Atlantic Margin.
DS2001-0536
2001
Jerusalem PostJerusalem PostUN condemns Israel over conflict diamondsJerusalem Post, Oct. 21, 1p.IsraelNews item, Conflict diamonds
DS1986-0406
1986
Jerzykiewicz, T.Jerzykiewicz, T., Sweet, A.R.The Cretaceous Tertiary Boundary in the central Alberta Foothills, I.stratigraphy.Canadian Journal of Earth Sciences, Vol. 23, pp. 1356-74.AlbertaCretaceous - boundary, Structure
DS1992-0788
1992
Jerzykiewicz, T.Jerzykiewicz, T., Norris, D.K.Field guidebook: anatomy of the Laramide foredeep and the structural style of the adjacent foreland thrust belt in southern AlbertaGeological Survey of Canada, Open File, No. 2549, 94p. $ 20.00AlbertaStructure, Laramide thrust
DS201510-1762
2015
Jesen, S.Cheirsirikul, S., Jesen, S., Hruanun, C.The MSM diamond device for direct and indirect X-ray detection.2015 IEEE 10th International Conference on Nan/Micro Engineered and Molecular Systems, NEMS 2015, pp. 372-374.TechnologyX-ray dectector

Abstract: Development synthesizing diamond film on silicon substrate was processed by Hot Filament Chemical Vapor Deposition (HFCVD). The gas processes using of H2 and CH4 to produce intrinsic diamond and MSM device constructed on the diaphragm of diamond film. Schottky junctions on the top and the lower diaphragm were produced by aluminum metal. After that, the result of detecting a direct and indirect X-ray of MSM diamond was satisfactory because it could respond along with increasing of X-ray intensity. The X-ray expose time of indirect expose by BaF2 scintillator faster more than direct expose.
DS1997-0548
1997
Jessberger, E.K.Jacobs, J., Falter, M., Jessberger, E.K.40 Ar-39 Ar thermochronological constraints on the structural evolution of the Mesoproterozoic Natal...Precambrian Research, Vol. 86, No. 1/2, Dec. 15, pp. 71-92GlobalMetamorphic province, Argon, Tectonics, structure
DS201504-0185
2015
Jessell, M.Block, S., Ganne, J., Baratoux, A.Z., Parra-Avila, L.A., Jessell, M., Ailleres, L., Siebenaller, L.Petrological and geochronological constraints on lower crust exhumation during Paleoproterozoic (Eburnean) Orogeny, NW Ghana, West African craton.Journal of Metamorphic Geology, Vol. 33, 5, pp. 463-494.Africa, GhanaGeochronology

Abstract: New petrological and geochronological data are presented on high-grade ortho- and paragneisses from northwestern Ghana, forming part of the Paleoproterozoic (2.25-2.00 Ga) West African Craton. The study area is located in the interference zone between N-S and NE--SW-trending craton-scale shear zones, formed during the Eburnean orogeny (2.15-2.00 Ga). High-grade metamorphic domains are separated from low-grade greenstone belts by high-strain zones, including early thrusts, extensional detachments and late-stage strike-slip shear zones. Paragneisses sporadically preserve high-pressure, low-temperature (HP-LT) relicts, formed at the transition between the blueschist facies and the epidote-amphibolite sub-facies (10.0-14.0 kbar, 520-600 °C), and represent a low (~15 °C km?1) apparent geothermal gradient. Migmatites record metamorphic conditions at the amphibolite-granulite facies transition. They reveal a clockwise pressure-temperature-time (P-T-t) path characterized by melting at pressures over 10.0 kbar, followed by decompression and heating to peak temperatures of 750 °C at 5.0-8.0 kbar, which fit a 30 °C km?1 apparent geotherm. A regional amphibolite facies metamorphic overprint is recorded by rocks that followed a clockwise P-T-t path, characterized by peak metamorphic conditions of 7.0-10.0 kbar at 550-680 °C, which match a 20-25 °C km?1 apparent geotherm. These P-T conditions were reached after prograde burial and heating for some rock units, and after decompression and heating for others. The timing of anatexis and of the amphibolite facies metamorphic overprint is constrained by in-situ U-Pb dating of monazite crystallization at 2138 ± 7 and 2130 ± 7 Ma respectively. The new data set challenges the interpretation that metamorphic breaks in the West African Craton are due to diachronous Birimian ‘basins’ overlying a gneissic basement. It suggests that the lower crust was exhumed along reverse, normal and transcurrent shear zones and juxtaposed against shallow crustal slices during the Eburnean orogeny. The craton in NW Ghana is made of distinct fragments with contrasting tectono-metamorphic histories. The range of metamorphic conditions and the sharp lateral metamorphic gradients are inconsistent with ‘hot orogeny’ models proposed for many Precambrian provinces. These findings shed new light on the geodynamic setting of craton assembly and stabilization in the Paleoproterozoic. It is suggested that the metamorphic record of the West African Craton is characteristic of Paleoproterozoic plate tectonics and illustrates a transition between Archean and Phanerozoic orogens.
DS201509-0403
2015
Jessell, M.Jessell, M., Santoul, J., Baratoux, L., Youbi, N., Ernst, R.E., Metelka, V., Miller, J., Perrouty, S.An updated map of West African mafic dykes.Journal of African Earth Sciences, in press availableAfrica, West AfricaGeophysics - magnetics

Abstract: Studies of mafic dyke swarms may simultaneously provide information on the mechanical, geochemical, geochronological and magnetic environments at the time of their formation. The mafic intrusive history of different cratons can also be potentially used to unravel their assembly into their current configuration. The identification and classification of dykes is a first step to all these studies. Fortunately, even in regions with poor outcrop, we can use the strong magnetic response of mafic dykes to identify and map their extent. In West Africa the first maps of mafic dyke distribution were made over 40 years ago, but there are still large areas where there are almost no published data. In this paper we present a significantly updated map of mafic dykes for the West Africa Craton based in large part on new interpretations of the regional airborne magnetic database. This map includes the locations of over three thousand dykes across the craton, which locally shows several orientation clusters that provide a minimum estimate for the total number of dyke swarms in this region. Whilst we will have to wait until systematic dating of the different swarms is completed, we can demonstrate that there is a long and complex history of mafic magmatism across the craton, with up to 26 distinct dyke swarms mapped based according to their orientation. The mapping and dating of these swarms will provide key constraints on the assembly of the fragments that make up the modern continents.
DS201510-1773
2015
Jessell, M.W.Jessell, M.W., Begg, G.C., Miller, M.S.The geophysical signatures of the West African Craton.Precambrian Research, in press available, 22p.Africa, West AfricaGeophysics - gravity

Abstract: This paper examines existing and newly compiled geophysical representations of the West African Craton (WAC) in terms of its large-scale tectonic architecture. In order to build an interpretation with a significant depth extent we draw upon a range of geophysical data, principally seismic tomographic inversions, receiver functions, gravity and magnetics. We present these results as a series of layers providing a series of depth slices though the cratonic lithosphere. The different geophysical methods suggest partitioning of the WAC into two tectonic elements at the largest scale which is observed in both seismic tomographic images, lithosphere-asthenosphere boundary (LAB) models and long wavelength gravity signals. The different models of the Moho, or crust-mantle boundary, based on these gravity or seismic datasets show little or no correlation, either for short or long-wavelength features, and show little correlation with new receiver function inferred crustal thickness estimates. Manual interpretation of low-wavelength gravity and magnetic data suggest a possible continuation of the WAC across the western margin of the modern boundary, and also highlight distinct domains interpreted to be of Birimian age.
DS201512-1940
2015
Jessell, M.W.Markwitz, V., Hein, K.A.A., Jessell, M.W., Miller, J.Metallogenic portfolio of the West African Craton. ( mentions kimberlites)Ore Geology Reviews, Oct 28 10.024Africa, West AfricaReguibat shield, Kenema-Man shield

Abstract: The West African Craton hosts major resources of gold, iron ore, aluminium ore, diamonds, phosphates and manganese. This portfolio of ore deposits is linked to the formation of Archean -Paleoproterozoic greenstone belts, Jurassic rifting and extended periods of Mesozoic to Cenozoic weathering and erosion. We give a brief overview of the temporal and spatial distribution patterns of West African ore deposits with emphasis on the main commodity types. The oldest ore forming processes generated major resources in iron ore and gold in the Kénéma -Man and Reguibat Shields during the Neo-Archean. The majority of gold, porphyry copper, lead -zinc and sedimentary manganese deposits formed during the Paleoproterozoic, dominantly within the Baoulé-Mossi domain. At the same time diamond-bearing kimberlites developed in Ghana. Another distinct diamond event has been recognized in the Mesozoic of the Kénéma -Man shield. Isolated occurrences of IOCG's as well as copper -gold and gold formed in Pan-African/Variscan belts. During the Neoproterozoic, the majority of mineralization consists of sedimentary iron ore and phosphate deposits located within intracratonic basins. During the Phanerozoic aluminium ore, phosphates and mineral sands concentrated along the margins of the coastal and intracratonic basins.
DS201604-0618
2016
Jessell, M.W.Markwitz, V., Hein, K.A.A., Jessell, M.W., Miller, J.Metallogenic portfolio of the West African craton. Mentions diamonds in S.L.Ore Geology Reviews, in press available 6p.Africa, Sierra LeoneMetallogeny
DS201608-1422
2016
Jessell, M.W.Markwitz, V., Hein, K.A.A., Jessell, M.W., Miller, J.Metallogenic portfolio of the West Africa craton. Mentions diamonds in Ghana, Mali and GuineaOre Geology Reviews, Vol. 78, pp. 558-563.Africa, Ghana, Mali, GuineaAlluvials
DS201902-0261
2019
Jessell, M.W.Baratoux, L., Soderlund, U., Ernst, R.E., de Roever, E., Jessell, M.W., Kamo, S., Naba, S., Perrouty, S., Metelka, V., Yatte, D., Grenholm, M., Diallo, D.P., Ndiaye, P.M., Dioh, E., Cournede, C., Benoit, M., Baratoux, D., Youbi, N., Rousse, S., BendaoudNew U-Pb baddeleyite ages of mafic dyke swarms of the West African and Amazonian cratons: implication for their configuration in supercontinents through time.Dyke Swarms of the World: a modern perspective, Srivastava et al. eds. Springer , pp. 263-314.Africa, West Africa, South Americageochronology

Abstract: Eight different generations of dolerite dykes crosscutting the Paleoproterozoic basement in West Africa and one in South America were dated using the high precision U-Pb TIMS method on baddeleyite. Some of the individual dykes reach over 300 km in length and they are considered parts of much larger systems of mafic dyke swarms representing the plumbing systems for large igneous provinces (LIPs). The new U-Pb ages obtained for the investigated swarms in the southern West African Craton (WAC) are the following (oldest to youngest): 1791?±?3 Ma for the N010° Libiri swarm, 1764?±?4 Ma for the N035° Kédougou swarm, 1575?±?5 for the N100° Korsimoro swarm, ~1525-1529 Ma for the N130° Essakane swarm, 1521?±?3 Ma for the N90° Sambarabougou swarm, 915?±?7 Ma for the N070° Oda swarm, 867?±?16 Ma for the N355° Manso swarm, 202?±?5 Ma and 198?±?16 Ma for the N040° Hounde swarm, and 200?±?3 Ma for the sills in the Taoudeni basin. The last ones are related to the Central Atlantic Magmatic Province (CAMP) event. The Hounde swarm is oblique to the dominant radiating CAMP swarm and may be linked with the similar-trending elongate Kakoulima intrusion in Guinea. In addition, the N150° Käyser swarm (Amazonian craton, South America) is dated at 1528?±?2 Ma, providing a robust match with the Essakane swarm in a standard Amazonia-West African craton reconstruction, and resulting in a combined linear swarm >1500 km by >1500 km in extent. The Precambrian LIP barcode ages of c. 1790, 1765-1750, 1575, 1520, 915. 870 Ma for the WAC are compared with the global LIP record to identify possible matches on other crustal blocks, with reconstruction implications. These results contribute to the refinement of the magmatic ‘barcode’ for the West African and Amazonian cratons, representing the first steps towards plausible global paleogeographic reconstructions involving the West African and Amazonian cratons.
DS202106-0950
2021
Jessell, M.W.Le Pape, F., Jones, A.G., Jessell, M.W., Hogg, C., Siebenaller, L., Perrouty, S., Tour, A., Oiuya, P., Boren, G.The nature pf the southern West Africa craton lithosphere inferred from its electrical resistivity.Precambrian Research, Vol. 358, 106190, 15p. Pdf Africageophysics

Abstract: The West-African craton is defined by a combination of Archean and Palaeoproterozoic rocks that stabilised at ~2 Ga towards the end of the Paleoproterozoic Eburnean Orogeny, and therefore may reflect the transition from Archean to modern tectonic processes. Exploring its present lithospheric architecture aids further understanding of not only the craton’s stability through its history but also its formation. We investigate the lithospheric structure of the craton through analysing and modelling magnetotelluric (MT) data from a 500-km-long east-west profile in northern Ghana and southern Burkina Faso crossing part of the Baoulé-Mossi Domain and reaching the Volta Basin in the south-eastern part of the craton. Although the MT stations are along a 2D profile, due to the complexity of the structures characterising the area, 3D resistivity modelling of the data is performed to obtain insights on the thermal signature and composition of the subcontinental lithosphere beneath the area. The thermal structure and water content estimates from different resistivity models highlight a strong dependence on the starting model in the 3D inversions, but still enable us to put constraints on the deep structure of the craton. The present?day thermal lithosphere?asthenosphere boundary (LAB) depth is estimated to be at least 250 km beneath the Baoulé-Mossi domain. The area likely transitions from a cold and thick lithosphere with relatively low water content into thinner, more fertile lithosphere below the Volta Basin. Although the inferred amount of water could be explained by Paleoproterozoic subduction processes involved in the formation of the Baoulé-Mossi domain, later enrichment of the lithosphere cannot be excluded.
DS1975-0299
1976
Jessie, B.Jessie, B.A Study of Kolo (lesotho) Kimberlites, Their Relation to Mantle Xenoliths and Orapa (botswana) Framesite Diamond Aggregates.Leeds University Research Institute of African Geology Annual Report, Vol. 20, 51P.Botswana, LesothoKimberlite Genesis, Peridotite, Chemical Analyses, Geochemistr
DS1999-0438
1999
Jessop, A.Majorowicz, J.A., Garven, G., Jessop, A., Jessop, C.Present heat flow along a profile across the Western Canada sedimentary basin; the extent hydrodynamic...Geothermics in Basin Analysis, Merriam Ed., pp. 61-79.Alberta, Western CanadaGeothermometry, Basin
DS1991-0795
1991
Jessop, A.M.Jessop, A.M., Ghomshei, M.M., Drury, M.J.Geothermal energy in CanadaGeothermics, Vol. 20, No. 5-6, pp. 369-385CanadaGeothermal energy, Overview
DS1991-0796
1991
Jessop, A.M.Jessop, A.M., Lewis, T.J., Drury, M.J.Terrestrial heat flow in CanadaTerrestrial Heat Flow and the Lithosphere Structure, editors Cermak, V. and, Springer Verlag, pp. 457-474CanadaHeat flow, Geophysics
DS1992-0789
1992
Jessop, A.M.Jessop, A.M.Thermal input from the basement of the Western Canada sedimentary basinCanadian Petroleum Geologists Bulletin, Vol. 40, No. 3, September pp. 198-206Saskatchewan, AlbertaHeat flow, Sedimentary basin
DS1999-0438
1999
Jessop, C.Majorowicz, J.A., Garven, G., Jessop, A., Jessop, C.Present heat flow along a profile across the Western Canada sedimentary basin; the extent hydrodynamic...Geothermics in Basin Analysis, Merriam Ed., pp. 61-79.Alberta, Western CanadaGeothermometry, Basin
DS1950-0398
1958
Jessop, J.E.JR.Jessop, J.E.JR.Glittering OasisGems And Gemology, Vol. 9, No. 8, WINTER, PP. 232-239.Southwest Africa, NamibiaMining Engineering, Methods
DS1989-0934
1989
Jessup, D.M.Mareschal, J.C., Hamdani, Y., Jessup, D.M.Downward continuation of heat flow dataTectonophysics, Vol. 164, No. 2-4, August 1, pp. 129-138GlobalMantle, Crust -heat flow
DS1975-1084
1979
Jessup, E.Jessup, E.Ernest Oppenheimer - a Study in PowerLondon: Rex Collins, 357P.Southwest Africa, Namibia, South AfricaDiamonds, Biography, Politics, History, Cdm, Kimberley
DS200712-0042
2007
Jetchum, J.Ayer, J., Hamilton, M., Jetchum, J., Stott, G., Wilson, A., Wyman, D.The age and provenance of Archean diamond bearing rocks in the Wawa area, northeastern Ontario.Diatreme breccias.Geological Association of Canada, Gac-Mac Yellowknife 2007, May 23-25, Volume 32, 1 pg. abstract p.4.Canada, Ontario, WawaDiatreme breccias
DS1994-0844
1994
Jewell, P.W.Jewell, P.W.Crustal evolution in South India: constraints from ND isotopesJournal of Geology, Vol. 102, No. 2, March pp. 139-150.IndiaTectonics, Geochronology
DS1860-0728
1892
Jewellers Circular KeystoneJewellers Circular KeystoneAnother Diamond Found in the Cracker StateJewellers Circular Keystone, Vol. 25, No. 14, Nov. 2ND. P. 20.United States, GeorgiaDiamond Occurrence
DS1860-0734
1892
Jewellers Circular KeystoneJewellers Circular KeystoneDiamondiferous Ground in Ada County, IdahoJewellers Circular Keystone, Vol. 25, No. 20, Dec. 4TH. P. 4.United States, Idaho, Rocky MountainsDiamond Occurrence
DS1860-0780
1893
Jewellers Circular KeystoneJewellers Circular KeystoneAttempt to Boom Georgia Property by Salting DiamondsJewellers Circular Keystone, Vol. 26, No. 9, MARCH 29TH. P. 17.United States, Georgia, Appalachialegal
DS1860-0785
1893
Jewellers Circular KeystoneJewellers Circular KeystoneThe Diamond Excitement in Idaho Not Yet on the WaneJewellers Circular Keystone, Vol. 25, No. 23, Jan. 4TH. PP. 12-13.United States, Idaho, Rocky MountainsLegal
DS1860-0786
1893
Jewellers Circular KeystoneJewellers Circular KeystoneDiamonds in Idaho, January, 1893Jewellers Circular Keystone, Vol. 25, No. 25, Jan. 18TH. P. 25.United States, Idaho, Rocky MountainsLegal
DS1860-0791
1893
Jewellers Circular KeystoneJewellers Circular KeystoneDiamonds in Wisconsin. #3Jewellers Circular Keystone, Vol. 27, No. 22, Dec. 27TH. P. 4.United States, Wisconsin, Great Lakes, Oregon, DaneDiamond Occurrence
DS1860-0833
1894
Jewellers Circular KeystoneJewellers Circular KeystoneA Plethora of Precious Stones Reported Found in MontanaJewellers Circular Keystone, Vol. 28, No. 23, JULY 11TH. P. 8.United States, Montana, Rocky MountainsDiamond Occurrence
DS1860-0916
1896
Jewellers Circular KeystoneJewellers Circular KeystoneThe Famous Diamonds of the WorldJewellers Circular Keystone , No. 189, 32P.GlobalDiamonds notable
DS1860-0965
1897
Jewellers Circular KeystoneJewellers Circular KeystoneRediscovery of Diamond Deposits in MexicoJewellers Circular Keystone, Vol. 34, No. 19, JUNE 9TH. P. 20.MexicoDiamond Occurrence
DS1860-0966
1897
Jewellers Circular KeystoneJewellers Circular KeystoneImproved Diamond MiningJewellers Circular Keystone, Vol. 25, Dec. 15TH. No. 13, P. 2.Africa, South AfricaMining Engineering
DS1860-1062
1899
Jewellers Circular KeystoneJewellers Circular KeystoneHow Diamonds Are Mined at KimberleyJewellers Circular Keystone, Vol. 39, No. 16, Nov. 15TH. PP. 1, 4, 7Africa, South Africa, Griqualand West, Kimberley AreaMining Engineering
DS1860-1070
1899
Jewellers Circular KeystoneJewellers Circular KeystoneDiamond Found at Milford OhioJewellers Circular Keystone, Vol. 37, No. 25, Jan. 18TH. P. 38.United States, Ohio, Great LakesDiamonds Notable
DS1900-0049
1901
Jewellers Circular KeystoneJewellers Circular KeystoneStones Found in New Mexico Pronounced Not to Be DiamondsJewellers Circular Keystone, Vol. 41, No. 24, Jan. 9TH. P. 30.United States, New Mexico, Colorado Plateaugemstone
DS1900-0096
1902
Jewellers Circular KeystoneJewellers Circular KeystoneJohannesburg Diamond Exporters Predict Rich Diamondiferous Strat a in Denver Colorado.Jewellers Circular Keystone, Vol. 45, No. 8, SEPT. 24TH. P. 53.United States, Colorado, Rocky MountainsDiamond Occurrence
DS1900-0097
1902
Jewellers Circular KeystoneJewellers Circular KeystoneCrystals Supposed to Be Diamonds Found in Berrien County, Georgia.Jewellers Circular Keystone, Vol. 45, No. 7, SEPT. 17TH. P. 28.United States, Georgia, Appalachia, MichiganDiamond Occurrence
DS1900-0100
1902
Jewellers Circular KeystoneJewellers Circular KeystoneOne Carat Diamond Found in IndianaJewellers Circular Keystone, Vol. 44, No. 17, MAY 28TH. P. 31.United States, Indiana, Great LakesDiamond Occurrence
DS1900-0101
1902
Jewellers Circular KeystoneJewellers Circular KeystoneDr. Day Gives a Statement Regarding the Alleged Diamond Discovery in Montana. He Suggests that they are Probably Sapphires.Jewellers Circular Keystone, Jan. 29TH.United States, Montana, Rocky MountainsDiamond Occurrence
DS1900-0237
1904
Jewellers Circular KeystoneJewellers Circular KeystoneAnother Supposed Diamond FieldJewellers Circular Keystone, Vol. 47, N0. 26, Jan. 27TH. P. 42A.United States, Kentucky, AppalachiaDiamond Occurrence
DS1900-0238
1904
Jewellers Circular KeystoneJewellers Circular KeystoneCompany Formed to Develop Alleged Diamond Fields in KentuckyJewellers Circular Keystone, Vol. 47, No. 26, Jan. 27TH. P. 28.United States, Kentucky, AppalachiaDiamond Occurrence
DS1900-0288
1905
Jewellers Circular KeystoneJewellers Circular KeystoneDiamond Fields in Guerrero MexicoJewellers Circular Keystone, Vol. 51, No. 16, Nov. 15TH. P. 28; P. 30.MexicoDiamond Occurrence
DS1900-0291
1905
Jewellers Circular KeystoneJewellers Circular KeystoneThe Kimberley Diamond Fields and the de Beers SystemJewellers Circular Keystone, Vol. 50, No. 24, Jan. 12TH. P. 94.Africa, South AfricaMining Engineering
DS1900-0305
1905
Jewellers Circular KeystoneJewellers Circular KeystoneSouth African Geologist to Look Over Alleged Diamond Fields in This Country.Jewellers Circular Keystone, Vol. 51, No. 5, AUG. 30TH. P. 26.United States, Kentucky, AppalachiaDiamond Occurrence, Diamonds Notable
DS1900-0306
1905
Jewellers Circular KeystoneJewellers Circular KeystoneSouth African Geologist Favourably Impressed with Supposed Diamond Fields of Kentucky.Jewellers Circular Keystone, Vol. 51, No. 7, SEPT. 13TH. P. 22.United States, Kentucky, AppalachiaDiamond Occurrence, Diamonds Notable
DS1900-0366
1906
Jewellers Circular KeystoneJewellers Circular KeystoneReport of a Diamond Find Lake NipissingJewellers Circular Keystone, Vol. 52, No. 26, AUG. 1ST. P. 55.Canada, OntarioDiamond Occurrence
DS1900-0385
1906
Jewellers Circular KeystoneJewellers Circular KeystoneSyndicate Formed to Develop Supposed Diamond Fields at Plumcity, Wisconsin.Jewellers Circular Keystone, Vol. 53, No. 9, Oct. 3RD. P. 49.United States, Great Lakes, WisconsinDiamond Occurrence, Diamonds Notable
DS1900-0395
1906
Jewellers Circular KeystoneJewellers Circular KeystoneSupposed Diamond Fields in the United States (us)Jewellers Circular Keystone, Vol. 53, No. 10, Oct. 10TH. P. 69.United States, Wisconsin, Kentucky, Great Lakes, AppalachiaDiamond Occurrence, Diamonds Notable
DS1900-0518
1907
Jewellers Circular KeystoneJewellers Circular KeystoneDiscovery of Diamonds in ArkansasJewellers Circular Keystone, Vol. 55, No. 2, AUGUST 14TH. PP. 63-64.United States, Gulf Coast, Arkansas, PennsylvaniaDiamond Occurrence
DS1900-0521
1907
Jewellers Circular KeystoneJewellers Circular KeystoneFurther Details as to the Arkansaw DiamondsJewellers Circular Keystone, Vol. 55, No. 2, AUGUST 7TH. P. 43; P. 45.United States, Gulf Coast, Arkansas, PennsylvaniaDiamond Occurrence
DS1900-0527
1907
Jewellers Circular KeystoneJewellers Circular KeystoneAnother Diamond Find Proves FictiousJewellers Circular Keystone, Vol. 55, No. 9, Oct. 2ND. P. 85.United States, Michigan, Great Lakes, PennsylvaniaDiamond Occurrence
DS1900-0607
1908
Jewellers Circular KeystoneJewellers Circular KeystoneAnother Diamond Mine SchemeJewellers Circular Keystone, Vol. 57, No. 5, SEPT. 2, P. 77.Canada, OntarioDiamond Occurrence
DS1900-0609
1908
Jewellers Circular KeystoneJewellers Circular KeystoneAnother Canadian Diamond Mining CompanyJewellers Circular Keystone, Vol. 57, No. 6, SEPT. 9TH. P. 63.Canada, QuebecDiamond Occurrence
DS1860-0689
1891
Jewellers ReviewJewellers ReviewThe Montana GemsJewellers Review, Dec. 12TH.United States, Montana, Rocky MountainsDiamond Occurrence
DS1860-0783
1893
Jewellers WeeklyJewellers WeeklyThe Idaho Diamonds FieldsJewellers Weekly, Vol. 15, No. 15, Jan. 4TH. P. 8.United States, Idaho, Rocky MountainsLegal
DS1860-0784
1893
Jewellers WeeklyJewellers WeeklyThe Idaho Diamond Fields (1893)Jewellers Weekly, Vol. 15, No. 17, Jan. 18TH. P. 7.United States, Idaho, Rocky MountainsLegal
DS1940-0028
1941
Jewett, J.B.Jewett, J.B.The Geology of Riley and Geary Counties, KansasKansas Geological Survey Bulletin, No. 39, 164P.United States, Kansas, Central StatesBlank
DS1950-0072
1951
Jewett, J.M.Jewett, J.M.Geologic Structure in KansasKansas Geological Survey Bulletin, No. 90, PT. 6, PP. 105-172.United States, Kansas, Central StatesBlank
DS2002-1371
2002
Jeyakumar, S.Roy, A., Sarkar, A., Jeyakumar, S., Aggrawal, S.K., Ebihara, M.Sm Nd age and mantle source characteristics of the Dhanjori volcanic rocks, eastern India.Geochemical Journal, Vol. 36, 5, pp. 503-18.IndiaGeochronology, magmatism
DS200512-0915
2004
Jeyakumar, S.Roy, A., Sarkar, A., Jeyakumar, S., Aggrawal, S.K., Ebihara, M., Satoh, H.Late Archean mantle metasomatism below eastern Indian Craton: evidence from trace elements, REE geochemistry and Sr Nd O isotope systematics of ultramafic dykes.Proceedings National Academy of Sciences India , Vol. 113, 4, pp. 649-666. Ingenta 1045680437IndiaMetasomatism, geochemistry
DS200512-0916
2004
Jeyakumar, S.Roy, A., Sarkar, A., Jeyakumar, S., Aggrawal, S.K., Ebihara, M., Satoh, H.Late Archean mantle metasomatism below eastern Indian craton: evidence from trace elements, REE geochemistry and Sr Nd O isotope systematics of ultramafic dykes.Proceedings National Academy of Sciences India , Vol. 113, 4, pp. 649-665.India, AsiaPeridotite, harzburgite, geochronology
DS1983-0332
1983
Jeynes, C.Jeynes, C.A Proposed Diamond Polishing ProcessPhilosophical Magazine., Vol. 48, No. 2, AUGUST, PP. 169-198.GlobalDiamond Cutting, Polishing
DS1910-0419
1914
Jezek, B.Jezek, B.Aus Dem Reiche der EdelsteinePrague:, PP. 32-42.GlobalDiamonds
DS1997-1151
1997
Jezek, J.Thompson, A.B., Schulmann, K., Jezek, J.Extrusive tectonics and elevation of lower crustal metamorphic rocks in convergent orogens.Geology, Vol. 25, No. 6, June pp. 491-494.MantleTectonics, Orogeny
DS1998-0918
1998
Jezek, K.C.Mahmood, A., Crawford, J.P., Michaud, R., Jezek, K.C.Mapping the world with remote sensingEos, Vol. 79, No. 2, Jan. 13, p. 17, 23.GlobalRemote Sensing, Radarsat
DS201112-0483
2010
Jezzini, K.Jezzini, K.Exploracao de diamantes no Rio Tibagi historia - atualidade - futuro.5th Brasilian Symposium on Diamond Geology, Nov. 6-12, abstract p. 19.South America, BrazilBrief - overview
DS201803-0462
2017
J-FLobanov, S.S., Holtgrewe, N., Lin, J-F, Goncharov, A.F.Radiative conductivity and abundance of post perovskite in the lower most mantle.Earth and Planetary Science Letters, Vol. 479, pp. 43-49.Mantleperovskite

Abstract: Thermal conductivity of the lowermost mantle governs the heat flow out of the core energizing planetary-scale geological processes. Yet, there are no direct experimental measurements of thermal conductivity at relevant pressure-temperature conditions of Earth's core-mantle boundary. Here we determine the radiative conductivity of post-perovskite at near core-mantle boundary conditions by optical absorption measurements in a laser-heated diamond anvil cell. Our results show that the radiative conductivity of Mg0.9Fe0.1SiO3 post-perovskite (?1.1 W/m/K) is almost two times smaller than that of bridgmanite (?2.0 W/m/K) at the base of the mantle. By combining this result with the present-day core-mantle heat flow and available estimations on the lattice thermal conductivity we conclude that post-perovskite is at least as abundant as bridgmanite in the lowermost mantle which has profound implications for the dynamics of the deep Earth.
DS201901-0046
2018
J-FLin, J-F, Mao, Z., Yang, J., Fu, F.Elasticity of lower-mantle bridgemanite.Nature, Vol. 564, pp. E18-E26.Mantlebridgmanite
DS202107-1140
2021
J-FSun, Y., Teng, F-Z., Pang, K-N., Ying, J-F, Kuehner, S.Multistage mantle metasomatism deciphered by Mg-Sr-Nd-Pb isotopes in the Leucite Hills lamproite.Contributions to Mineralogy and Petrology, Vol. 176, 45, 10.1007/s00410-021-01801-9 pdfUnited States, Wyomingdeposit - Leucite Hills

Abstract: Cratonic lamproites bear extreme Sr?Nd?Pb isotopic compositions widely known as enriched mantle I (EMI), yet the origin of the EMI reservoir remains controversial. Here, we explore this issue by examining Mg?Sr?Nd?Pb isotopic compositions of lamproites from Leucite Hills, Wyoming, USA. The ?26Mg values vary from the range of the normal mantle to lower values (? 0.43 to ? 0.18 ‰), correlating with indices of the degree of carbonate metasomatism, an observation that can be best explained through mantle metasomatism by subducted carbonate-bearing sediments. With increasing extent of carbonate metasomatism, these samples display less extreme EMI Sr?Nd?Pb isotopic signatures, arguing for at least two metasomatic events that occurred in their mantle sources. The early metasomatic event associated with subducted continent-derived siliciclastic sediments led to the formation of the EMI Sr?Nd?Pb isotopic signatures while the recent carbonate metasomatism produced the light Mg isotopic signature but diluted the EMI Sr?Nd?Pb isotopic signatures. Our study indicates that a combination of Mg and Sr?Nd?Pb isotopes could be an effective tool in deciphering multiple-stage metasomatic events in mantle sources and places new constraints on the generation of enriched mantle reservoirs.
DS201706-1094
2017
J-GLu, J-G, Xiong, Q., Griffin, W.L., Zheng, J-P., Huang, J-X., O'Reilly, S.Y., Satsuskawa, T., Pearson, N.J.Uplift of the southeastern Australian lithosphere: thermal tectonic evolution of garnet pyroxenite xenoliths from western Victoria.Geological Society of America, SPE 526 pp. 27-48.Australiageothermometry

Abstract: Detailed petrography, microstructure, and geochemistry of garnet pyroxenite xenoliths in Holocene basanite tuffs from maars at Lakes Bullenmerri and Gnotuk (western Victoria, southeastern Australia) have been used to track their igneous and metamorphic history, enabling the reconstruction of the thermal-tectonic evolution of the lithospheric mantle. The exsolution of orthopyroxene and garnet and rare spinel, plagioclase, and ilmenite from complex clinopyroxene megacrysts suggests that the xenoliths originally were clinopyroxene-dominant cumulates associated with minor garnet, orthopyroxene, or spinel. The compositions of exsolved phases and their host clinopyroxene were reintegrated using measured modal proportions to show that the primary clinopyroxene was enriched in Al2O3 (5.53-13.63 wt%) and crystallized at ~1300-1500 °C and 16-30 kbar. These cumulates then underwent extensive exsolution, recrystallization, and reaction during cooling, and finally equilibrated at ~950-1100 °C and 12-18 kbar before entrainment in the basanites. Rare earth element (REE) thermobarometry of garnets and coexisting clinopyroxenes preserves evidence of an intermediate stage (1032 °C and 21 kbar). These results imply that the protoliths of the garnet pyroxenite formed at a range of depths from ~50 to 100 km, and then during or shortly after cooling, they were tectonically emplaced to higher levels (~40-60 km; i.e., uplifted by at least 10-20 km) along the prevailing geotherm. This uplift may have been connected with lithosphere-scale faulting during the Paleozoic orogeny, or during Mesozoic-Cenozoic rifting of eastern Australia.
DS200712-0826
2007
J-HPeng, P., Zhai, M-G., Guo, J-H, Kusky, T.,Ping, T.Nature of mantle source contributions and crystal differentiation in the petrogenesis of the 1.78 Ga mafic dykes in the central North Chin a Craton.Gondwana Research, Vol. 12, 1-2, August pp. 29-46.ChinaDyke chemistry
DS200712-0827
2007
J-HPeng, P., Zhai, M-G., Guo, J-H, Kusky, T.,Ping, T.Nature of mantle source contributions and crystal differentiation in the petrogenesis of the 1.78 Ga mafic dykes in the central North Chin a Craton.Gondwana Research, Vol. 12, 1-2, August pp. 29-46.ChinaDyke chemistry
DS200812-1292
2008
J-HYang, J-H, Wu, F-Y., Wilde, S.A., Belousova, E., Griffin, W.L.Mesozoic decratonization of the North Chin a block.Geology, Vol. 36, 6, June pp. 467-470.ChinaCraton
DS1995-1331
1995
JhaNeeharika, Jha, Smith, S.B., Griffin, B.J., ChatterjeeDiamonds from the kimberlites of southeastern Raipur kimberlite field, Raipur district, Madhya Pradesh.Proceedings of the Sixth International Kimberlite Conference Abstracts, pp. 266-268.India, Madhya PradeshDiamond morphology, Deposit -Payalikand, Bahradih
DS201312-0440
2013
Jha, A.P.Jha, A.P.Mindfulness can improve your attention and health. * just for interest!!!Scientific American, March 15, preview of article to be publishedTechnologyHealth
DS1994-0286
1994
Jha, N.Chatterjee, B., Jha, N., Mishra, B.K., Kumar, M.Kondomali kimberlitic diatreme Raipur District Madhya-PradeshCurrent Science, Vol. 67, No. 1, July 10, pp. 50-52.IndiaKimberlite, Deposit -Kondomali
DS201904-0780
2019
Jha, R.Sinha, S.T., Saha, S., Longacre, M., Basu, S., Jha, R., Mondal, T.Crustal architecture and nature of continental breakup along a transform margin: new insights from Tanzania-Mozambique margin.Tectonics, in press availableAfrica, Tanzania, Mozambiquerifting

Abstract: The Tanzania?North Mozambique continental margin is a transform segment associated with Davie Fracture Zone (DFZ). The DFZ is described as an elongated linear oceanic fracture zone, commonly linked with the breakup between Eastern and Western Gondwana. We conducted a synthesized study using gravity, magnetic and seismic data presenting the crustal architecture, geometry and the kinematic nature of continental breakup along a transform margin. The Crustal nature of DFZ, its role in forming kinematic linkage between two extensional margins during continental breakup processes is focus of our study. The two extensional margins, Somalia?Majunga and North Mozambique?Antarctica were linked via a 2600 km long dextral transform segment, partially overlapping with DFZ. Absence of classical rift indicators, weak signs of hyperextension, abrupt ocean?continent boundary (OCB) suggests transform margin architecture. We redefined this feature as the Davie Transform System (DTS). The nature of deformation varies form transtensional pull?apart in Tanzania to almost pure strike?slip in North Mozambique. The southern transform segment exhibits abrupt change in ocean continent transition with a narrow zone of continental extension. This variation is recognized through the newly interpreted OCB along this entire transform segment. Notably, within large pull?apart systems in the north, presence of fossilized incipient spreading center suggest that the extension had reached at quite advanced stages, characterized by significant thermal weakening as a consequence of strong magmatic activity. Through a series of reconstruction snapshots, we show the geodynamic evolution along the Tanzania?North Mozambique margin explaining the role of DTS in the southward movement of Madagascar.
DS201502-0083
2014
Jha, S.Mukherjee, A., Jha, S., Babu, E.V.S.S.K., Verma, C.B.Discovery of a kimberlite pipe near Budikonda, Dharwar craton, south India: field approaches, preliminary petrography and mineral chemistry. KL-7Journal of the Geological Society of India, Vol. 84, 6, pp. 633-644.India, South IndiaKalyandurg cluster
DS202107-1101
2018
Jha, S.K.Guha, A., Rani, K., Varma, C.B., Sarwate, N.K., Sharma, N., Mukherjee, A., Kumar, K.V., Pal, S.K., Saw, A.K., Jha, S.K.Identification of potential zones for kimberlite exploration - an Earth observation approach. ChhatarpurThe International Achives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol. XLII-5 12p. PdfIndia, Madhya PradeshASTER, lineament

Abstract: In the present study, we have prepared the thematic evidence layers for identifying the potential zones of kimberlite emplacement in parts of Chhatarpur district, Madhya Pradesh. These thematic layers or evidence layers are geological structure, alteration zones, lineament density, surface alteration and geomorphic anomaly and these layers are prepared from the remote sensing data. As orientation of the geological structures (i.e fault system) and their density have the major role in the emplacement of kimberlite; both of these evidence layers are integrated using "AND" Boolean Logical Operator. On the other hand, two evidential layers regarded as the proxy to indicate the "surface expressions on kimberlite (i.e. alteration zones and geomorphic anomaly) are combined using "OR" operator as either of these two surface expression is indicative of kimberlite. Consequently, conjugate evidence layers on the surface expressions of kimberlite are integrated with the causative evidence layers of kimberlite emplacement using "AND" operator to identify the potential zones of diamond occurrences. Potential zones of kimberlite are overlaid on the residual gravity anomaly map derived from space-based gravity model of European Improved Gravity of Earth by New Technique (EIGEN6C4) to relate potential zones of kimberlite with the similar structural alignment (delineated in the residual gravity map) of known occurrence of kimberlite. We also have carried out indicator mineral survey around these potential zones and some of the kimberlite specific indicator minerals are identified in the stream sediments within these potential zones.
DS1950-0280
1956
Jhingran, A.G.Jhingran, A.G., Puri, S.N.A New Find of Agglomeratic Tuff in Bundelk hand Granite Area in Chhatarpur District.Proceedings FOURTY THIRD INDIA SCI. CONG., PT. II, P. 169. (abstract.).India, Madhya PradeshAngore
DS201012-0235
2009
Jhonson, M.Gilbertson, A., Gudlewski, B., Jhonson, M., Maltezos, G., Scherer, A., Shigley, J.Cutting diffraction gratings to improve dispersion ( 'fire') in diamonds. A new process of plasma eteching diffraction patterns on diamond facets.Gems & Gemology, Vol. 45, 4, Winter pp. 260-270.TechnologyDiamond cutting
DS1995-1168
1995
JiMareschal, M., Kellett, R.L., Kurtz, R.D., Ludden, JiArchean cratonic roots, mantle shear zones and deep electrical anisotropy.Nature, Vol. 375, No. 6527, May 11, pp. 134-136MantleCraton, Geophysics -seismics
DS2002-0445
2002
JiFang, W., Hu, Su, Xio, Ji, JiangOn emplacment ages of lamproite in Zhenyuan County, Guizhon Province, ChinaChina Sciences Bulletin, Vol.47, 10,pp. 874-80.China, GuizhonGeochronology, Lamproites
DS1996-0684
1996
Ji, S.Ji, S., Rondenay, S., Senechal, G.Obliquity between seismic and electrical anisotropies as potential indicator of movement sense for ductile .Geology, Vol. 24, No. 11, Nov. pp. 1033-36MantleShear zones, Geophysics - seismics
DS2001-1015
2001
Ji, S.Saruwatari, K., Ji, S., Long, C., Saisbury, M.H.Seismic anisotropy of mantle xenoliths and constraints on upper mantle structure beneath southern Cordillera.Tectonophysics, Vol. 339, No. 3-4, pp. 403-26.Mantle, British ColumbiaGeophysics - seismics, Xenoliths
DS2003-0656
2003
Ji, S.Ji, S., Saruwateri, K., Mainproce, D., Wirth, R., Xu, Z., Xia, B.Microstructures, petrofabrics and seismic properties of ultra high pressure eclogitesTectonophysics, Vol. 370, 1-4, pp. 49-76.ChinaGeophysics - seismics, UHP, subduction
DS200412-0915
2003
Ji, S.Ji, S., Saruwateri, K., Mainproce, D., Wirth, R., Xu, Z., Xia, B.Microstructures, petrofabrics and seismic properties of ultra high pressure eclogites from Sulu region, China: implications forTectonophysics, Vol. 370, 1-4, pp. 49-76.ChinaGeophysics - seismics UHP, subduction
DS200512-1164
2005
Ji, S.Wang, Q., Ji, S., Salisbury, M.H., Xia, B., Pan, M., Xu, Z.Pressure dependence and anisotropy of P wave velocities in ultrahigh pressure metamorphic rocks from the Dabie Sulu orogenic belt: implications for seismic propertiesTectonophysics, Vol. 398, 1-2, pp. 67-99.ChinaMantle reflections, subduction slabs
DS200512-1207
2005
Ji, S.Xu, S., Liu, Y., Chen, G., Ji, S., Ni, P., Xiao, W.Microdiamonds, their classification and tectonic implications for the host eclogites from the Dabie and Su-Lu regions in central eastern China.Mineralogical Magazine, Vol. 69, 4, Aug. pp. 509-520.ChinaUHP, microdiamonds
DS200612-1506
2005
Ji, S.Wang, Q., Ji, S., Salisbury, M.H., Xia, B., Pan, M., Xu, Z.Shear wave properties and Poisson's ratios of ultrahigh pressure metamorphic rocks from Dabie Sulu orogenic belt.Journal of Geophysical Research, Vol. 110, B8, BO8208.ChinaUHP
DS200612-1560
2006
Ji, S.Xu, Z., Wang, Q., Ji, S., Chen, J., Zeng, Yang, Chen, Liang, WenkPetrofabrics and seismic properties of garnet peridotite from the UHP Sulu terrane: implications for olivine deformation mechanism in subducting slab.Tectonophysics, Vol. 421, 1-2, pp. 111-127.MantleSubduction - cold, dry continental slab
DS200912-0827
2008
Ji, S.Xu, S., Wu, W., Xiao, W., Yang, J., Chen, J., Ji, S., Liu, Y.Moissanite in serpentine from the Dabie Mountains in China.Mineralogical Magazine, Vol. 72, 4, pp. 899-908.ChinaUHP
DS201012-0324
2010
Ji, S.Ji, S., Quia,S.S., Marcotte, D.Lam parameters of common rocks in the Earth's crust and upper mantle.Journal of Geophysical Research, Vol. 115, B6, B06314.MantleGeophysics - seismics
DS201510-1815
2015
Ji, S.Xu, S., Liu, Y., Chen, G., Ji, S., Ni, P., Xiao, W.Microdiamonds, their classification and tectonic implications for the host eclogites from the Dabie and Su-Lu regions in central eastern China.Mineralogical Magazine, Vol. 69, 4, pp. 590-520.ChinaUHP

Abstract: We have found >10 in situ microdiamonds in thin sections of eclogites from the Dabie and Su-Lu regions of central eastern China since the first occurrence of microdiamond in eclogites from the Dabie Mountains (DMT) reported in 1992. The microdiamonds are found not only in the central part but also in the northern part of the DMT. Several free crystals have been recovered from the crushed eclogites from the central DMT. Most in situ microdiamonds are inclusions in garnets but a few larger ones are intergranular. Most of the diamondiferous eclogites in the central part of the DMT are associated with coesite. Most importantly, the observation of microdiamonds in northern Dabie lead us to question the supposition that this is a low-P metamorphic terrane. All the diamondiferous eclogites from both the north and central DMT are of continental affinity as demonstrated by their negative ?Nd values. Therefore, both the north and central eclogite belts in the DMT are considered to be from the deep subducted terrane. Five in situ microdiamonds and two free crystals are first reported in this paper. The dimensions of the in situ microdiamonds are 30-80 ?m and the free crystals are up to 400–-00 ?m across. All the microdiamonds are confirmed as such by Raman spectroscopy. The results of an infrared spectroscopic investigation on two larger free crystals and two in situ microdiamonds show that all the microdiamonds from both the Dabie and Su-Lu regions are mixed types IaA and IaB diamonds and there is no indication of any synthetic microdiamonds in our samples because such synthetic microdiamonds are always rich in type Ib.
DS1994-0845
1994
Ji, S.C.Ji, S.C., Zhao, P..Layered rheological structure of subducting oceanic lithosphereEarth Planet. Science Letters, Vol. 124, No. 1-4, June pp. 75-94.MantleTectonics, Subduction
DS1992-1706
1992
Ji, S.Y.Xu, Shutong, Okay, A.I., Ji, S.Y., Sengor, A.H.C., Wen, S., LiuDiamond from the Dabie-Shaw metamorphic rocks and its implication for tectonic settingScience, Vol. 256, No. 5053, April 3, pp. 80-82ChinaMetamorphic rocks, Diamonds
DS201312-0812
2014
Ji, W.Shi, Y., Lin, W., Ji, W., Wang, Q.The architecture of the HP-UHP Dabie Massif: new insights from geothermobarometry of eclogites and implication for the continental exhumation processes.Journal of Asian Earth Sciences, Vol. 86, pp. 38-58.ChinaUHP
DS202102-0226
2021
Ji, W-Q.Tang, M., Ji, W-Q., Chu, X., Wu, A., Chen, C.Reconstructing crustal thickness evolution from europium anomalies in detrital zircons.Geology, Vol. 49, pp. 76-80. pdfAsia, Tibetzircons

Abstract: A new data compilation shows that in intermediate to felsic rocks, zircon Eu/Eu* [chondrite normalized Eu/ graphic] correlates with whole rock La/Yb, which has been be used to infer crustal thickness. The resultant positive correlation between zircon Eu/Eu* and crustal thickness can be explained by two processes favored during high-pressure differentiation: (1) supression of plagioclase and (2) endogenic oxidation of Eu2+ due to garnet fractionation. Here we calibrate a crustal thickness proxy based on Eu anomalies in zircons. The Eu/Eu*-in-zircon proxy makes it possible to reconstruct crustal thickness evolution in magmatic arcs and orogens using detrital zircons. To evaluate this new proxy, we analyzed detrital zircons separated from modern river sands in the Gangdese belt, southern Tibet. Our results reveal two episodes of crustal thickening (to 60-70 km) since the Cretaceous. The first thickening event occurred at 90-70 Ma, and the second at 50-30 Ma following Eurasia-India collision. These findings are temporally consistent with contractional deformation of sedimentary strata in southern Tibet.
DS202105-0773
2021
Ji, Z.Liang, Y., Ji, Z., Liu, B.What can we learn from REE abundances in clinopyroxene and orthopyroxene in residual mantle peridotites?Contributions to Mineralogy and Petrology, 176, 19p. PdfMantleREE

Abstract: Clinopyroxene and orthopyroxene are the two major repositories of rare earth elements (REE) in spinel peridotites. Most geochemical studies of REE in mantle samples focus on clinopyroxene. Recent advances in in situ trace element analysis has made it possible to measure REE abundance in orthopyroxene. The purpose of this study is to determine what additional information one can learn about mantle processes from REE abundances in orthopyroxene coexisting with clinopyroxene in residual spinel peridotites. To address this question, we select a group of spinel peridotite xenoliths (9 samples) and a group of abyssal peridotites (12 samples) that are considered residues of mantle melting and that have major element and REE compositions in the two pyroxenes reported in the literature. We use a disequilibrium double-porosity melting model and the Markov chain Monte Carlo method to invert melting parameters from REE abundance in the bulk sample. We then use a subsolidus reequilibration model to calculate REE redistribution between cpx and opx at the extent of melting inferred from the bulk REE data and at the closure temperature of REE in the two pyroxenes. We compare the calculated results with those observed in clinopyroxene and orthopyroxene in the selected peridotitic samples. Results from our two-step melting followed by subsolidus reequilibration modeling show that it is more reliable to deduce melting parameters from REE abundance in the bulk peridotite than in clinopyroxene. We do not recommend the use of REE in clinopyroxene alone to infer the degree of melting experienced by the mantle xenolith, as HREE in clinopyroxene in the xenolith are reset by subsolidus reequilibration. In general, LREE in orthopyroxene and HREE in clinopyroxene are more susceptible to subsolidus redistribution. The extent of redistribution depends on the modes of clinopyroxene and orthopyroxene in the sample and thermal history experienced by the peridotite. By modeling subsolidus redistribution of REE between orthopyroxene and clinopyroxene after melting, we show that it is possible to discriminate mineral mode of the starting mantle and cooling rate experienced by the peridotitic sample. We conclude that endmembers of the depleted MORB mantle and the primitive mantle are not homogeneous in mineral mode. A modally heterogeneous peridotitic starting mantle provides a simple explanation for the large variations of mineral mode observed in mantle xenoliths and abyssal peridotites. Finally, by using different starting mantle compositions in our simulations, we show that composition of the primitive mantle is more suitable for modeling REE depletion in cratonic mantle xenoliths than the composition of the depleted MORB mantle.
DS202110-1625
2021
Jia, H.Lu, Z., Zhao, H., Wang, Y., Fang, S., Cai, Z., Wang, Z., Ma, H-a., Chen, L., Jia, H., Jia, X.Diamond growth and characteristics in the metal-silicate-H2O-C system at HPHT conditions.Lithos, Vol. 404-405, 106470, 11p. PdfMantlediamond crystals

Abstract: The detailed phase composition and characteristics of diamond crystals grown in the metal-silicate-H2O-C system at 5.5 GPa and 1385 °C are reported in this paper. The conversion efficiency of the graphite-to-diamond in the metal-silicate-C system is lower than that in the metal-C system, which significantly decreases the growth rate of crystal. As the Mg2Si3O8•5H2O content increases to 1.5 wt%, growth pits and {110} related features of trigonal pyramids, skeletal structure, rhombic dodecahedron, and {110} dendrites exhibit in sequence. Simultaneously, the content of graphite and metal inclusions inside the crystal increases. These systematic changes are accompanied by the appearance of Csingle bondH, Csingle bondO, and Cdouble bondO bonds and a decrease of nitrogen content from ?210 ppm to ?60 ppm. It is speculated that H2O will further decompose and bond with carbon atoms and finally enter the diamond structure. The formation of Csingle bondH and Cdouble bondO bonds will terminate the extension of the three-dimensional network of Csingle bondC bonds. These defects will accumulate along the [111] direction and form {110} related characteristics. These chemical bonds also compete with the nitrogen in the system during entering into the diamond lattice. Our experimental model may provide implications for the morphology and formation environment of natural diamonds.
DS201112-0591
2011
Jia, J.Li, H., Li, S., Song, D., Gong, M., Li, X., Jia, J.Crustal and uppermost mantle velocity structure beneath northwestern Chin a from seismic ambient noise tomography.Geophysical Journal International, in press availableChinaGeophysics - seismics
DS201909-2093
2019
Jia, L-H.Su, B., Chen, Y., Mao, Q., Zhang, D., Jia, L-H., Guo, S.Minor elements in olivine inspect the petrogenesis of orogenic peridotites. Dabie -SuluLithos, Vol. 344-345, pp. 207-216.ChinaUHP
DS202105-0795
2021
Jia, L-H.Tang, Li., Wagner, T.,Fusswinkel, T., Zhang, S-T., Xi, B., Jia, L-H., Hu, X-K. Magmatic-hydrothermal evolution of an unusual Mo-rich carbonatite: a case study using LA-ICP-MS fluid inclusion microanalysis and He-Ar isotopes from the Huangshuian deposit, Qinling, China.Mineralium Deposita, 10.1007/s00126 -021-01055-2 18p. PdfChinacarbonatites

Abstract: The Huangshui'an deposit located in East Qinling (China) is an unusual case of a Si-rich carbonatite hosting economic Mo and minor Pb and REE mineralization. The role of mantle-sourced carbonatite melts and fluids in the formation of the Mo mineralization remains poorly understood. Our integrated study based on field geology, petrography, microthermometry, and LA-ICP-MS analysis of single fluid inclusions, and noble gas isotopes of pyrite permits to reconstruct the source characteristics, the magmatic-hydrothermal evolution of the carbonatitic fluids, and their controls on Mo mineralization. Fluid inclusions hosted in calcite in the carbonatite dikes have the highest concentrations of Mo (9.9-62 ppm), Ce (820-9700 ppm), Pb (1800-19500 ppm), and Zn (570-5800 ppm) and represent the least modified hydrothermal fluid derived from the carbonatite melt. Fluid inclusions hosted in calcite (Cal) and quartz (Qz2 and Qz3) of the stage I carbonatite dikes have different metal concentrations, suggesting that they formed from two distinct end member fluids. The FIA in calcite represent fluid A evolved from carbonatite melt with relatively high-ore metal concentrations, and those in quartz characterize fluid B having a crustal signature due to metasomatic reactions with the wall rocks. The FIA in quartz (Qz1) within the altered wall rock have overlapping elemental concentrations with those of massive quartz (Qz2) and vuggy quartz (Qz3) in carbonatite. This suggests that the volumetrically significant quartz in the Huangshui'an carbonatite has been formed by the introduction of Si by fluid B. The positive correlations between Rb, B, Al, Cl, and Sr in stage II fluid inclusions in late fluorite + quartz + calcite veins indicate that this late mineralization formed from the mixing of primary hydrothermal fluid B with meteoric water. The He-Ar isotope data, in combination with available C-O-Sr-Nd-Pb isotope data, constrain the carbonatite source as an enriched mantle source modified by contributions from crustal material which was probably the fertile lower crust in the region. This distinct source facilitated the enrichment in Mo, REE, and Pb in the primary carbonatite magma. The carbonatite magmatism and Mo mineralization at 209.5-207 Ma occurred in the regional-scale extensional setting at the postcollision stage of the Qinling Orogenic Belt.
DS202108-1310
2021
Jia, L-H.Tang, L., Wagner, T., Fusswinkel, T., Zhang, S-T., Xu, B., Jia, L-H.Magmatic-hydrothermal evolution of an unusual Mo-rich carbonatite: a case study using LA-ICP-MS fluid inclusion microanalysis and He-Ar isotopes from the Huanshuiian deposit, Qinling, China.Mineralium Deposita, 18p. PdfChinadeposit - Huanshuian

Abstract: The Huangshui'an deposit located in East Qinling (China) is an unusual case of a Si-rich carbonatite hosting economic Mo and minor Pb and REE mineralization. The role of mantle-sourced carbonatite melts and fluids in the formation of the Mo mineralization remains poorly understood. Our integrated study based on field geology, petrography, microthermometry, and LA-ICP-MS analysis of single fluid inclusions, and noble gas isotopes of pyrite permits to reconstruct the source characteristics, the magmatic-hydrothermal evolution of the carbonatitic fluids, and their controls on Mo mineralization. Fluid inclusions hosted in calcite in the carbonatite dikes have the highest concentrations of Mo (9.9-62 ppm), Ce (820-9700 ppm), Pb (1800-19500 ppm), and Zn (570-5800 ppm) and represent the least modified hydrothermal fluid derived from the carbonatite melt. Fluid inclusions hosted in calcite (Cal) and quartz (Qz2 and Qz3) of the stage I carbonatite dikes have different metal concentrations, suggesting that they formed from two distinct end member fluids. The FIA in calcite represent fluid A evolved from carbonatite melt with relatively high-ore metal concentrations, and those in quartz characterize fluid B having a crustal signature due to metasomatic reactions with the wall rocks. The FIA in quartz (Qz1) within the altered wall rock have overlapping elemental concentrations with those of massive quartz (Qz2) and vuggy quartz (Qz3) in carbonatite. This suggests that the volumetrically significant quartz in the Huangshui'an carbonatite has been formed by the introduction of Si by fluid B. The positive correlations between Rb, B, Al, Cl, and Sr in stage II fluid inclusions in late fluorite + quartz + calcite veins indicate that this late mineralization formed from the mixing of primary hydrothermal fluid B with meteoric water. The He-Ar isotope data, in combination with available C-O-Sr-Nd-Pb isotope data, constrain the carbonatite source as an enriched mantle source modified by contributions from crustal material which was probably the fertile lower crust in the region. This distinct source facilitated the enrichment in Mo, REE, and Pb in the primary carbonatite magma. The carbonatite magmatism and Mo mineralization at 209.5-207 Ma occurred in the regional-scale extensional setting at the postcollision stage of the Qinling Orogenic Belt.
DS200912-0864
2009
Jia, X.Zhou, S., Zang, C., Ma, H., Li, X., Zhang, H., Jia, X.Study on growth of coarse grains of diamond with high quality under HPHT.Chinese Science Bulletin, Vol. 54, 1, pp. 163-167.TechnologyUHP
DS201703-0410
2017
Jia, X.Jia, X., Wang, X., Yang, W.Petrogenesis and geodynamic implications of the Early Paleozoic potassic and ultrapotassic rocks in the south Chin a block.Journal of Asian Earth Sciences, Vol. 135, pp. 80-94.ChinaAlkaline rocks

Abstract: In this paper, some potassic and ultrapotassic rocks in the South China Block (SCB) have been recognized, according to a set of new geochronological, geochemical and Sr-Nd isotopic data. Zircon U-Pb dating from six plutons yield consistent crystallization ages of 445-424 Ma. These potassic and ultrapotassic rocks can be geochemically subdivided into three groups. Group 1, represented by the Longchuan gabbro, longmu diabase, Tangshang and Danqian diorite (445-433 Ma), have low silica contents (SiO2 = 47.38-54.16 wt.%), and high MgO (4.21-9.51 wt.%) and total alkalis (Na2O + K2O = 3.08-5.57 wt.%), with K2O/Na2O ratios of 0.62-1.82. They are enriched in LREE and depleted in Ba, Sr and Ta-Nb-Ti, and exhibit relatively high initial 87Sr/86Sr ratios (0.70561-0.71128), low ?Nd(430 Ma) values (?8.4 to ?3.2), suggesting that they were most plausibly generated by the partial metling of enriched mantle source (EMI). Group 2, from the Huwei diorite (424 Ma), have 45.68-52.87 wt.% of SiO2, 5.79-9.25 wt.% of MgO and 52-65 of mg-number. They have significantly higher Th (9.92 ppm), Ce (88.0-115 ppm) concentration and Ce/Yb (27.6-46.8), Th/Yb ratios (2.58-7.99), and relatively low initial 87Sr/86Sr ratios (0.70501-0.70599), and high ?Nd(430 Ma) values (?2.1 to ?1.5). We propose that they originated from the partial melting of the depleted mantle source with subsequent contamination by crustal materials. Group 3, represented by the Daning lamprophyre (?445 Ma), has SiO2 contents ranging from 41.73 wt.% to 45.22 wt.%, MgO from 13.74 wt.% to 15.16 wt.%, and mg-muber from 73 to 77, with high K2O/Na2O ratios (>2.0). They have 87Sr/86Sr ratios of 0.62912-0.70384 and ?Nd(t = 430 Ma) values of ?6.4 to ?6.3, indicating that the source components are close to the EMI source, with significant sediments involved. These Silurian potassic and ultrapotassic rocks in the SCB can be responsible for post-orogenic delamination and intra-plate extension. And the delamination had a small size and a long duration, and a negligible impact.
DS201802-0225
2018
Jia, X.Chen, N., Ma, H., Chen, L., Yan, B., Fang, C., Liu, X., Li, Y., Guo, L., Chen, L., Jia, X.Effects of S on the synthesis of type 1b diamond under high pressure and high temperature.International Journal of Refractory Metals & Hard Materials, Vol. 71, pp. 141-146.Technologysynthetic diamonds
DS201807-1508
2018
Jia, X.Liu, H., Wang, W., Jia, X., Leng, W., Wu, Z., Sun, D.The combined effects of post-spinel and post-garnet phase transitions on mantle plume dynamics.Earth and Planetary Science Letters, Vol. 496, pp. 80-88.Mantleperovskite, hotspots

Abstract: Mineralogical studies indicate that two major phase transitions occur near the depth of 660 km in the Earth's pyrolitic mantle: the ringwoodite (Rw) to perovskite (Pv) + magnesiowüstite (Mw) and the majorite (Mj) to perovskite (Pv) phase transitions. Seismological results also show a complicated phase boundary structure at this depth in plume regions. However, previous geodynamical modeling has mainly focused on the effects of the Rw-Pv+Mw phase transition on plume dynamics and has largely neglected the effects of the Mj-Pv phase transition. Here, we develop a 3-D regional spherical geodynamic model to study the combined influence of these two phase transitions on plume dynamics. Our results show the following: (1) A double phase boundary occurs in the high-temperature center of the plume, corresponding to the double reflections in seismic observations. Other plume regions feature a single, flat uplifted phase boundary, causing a gap of high seismic velocity anomalies. (2) Large amounts of relatively low-temperature plume materials can be trapped in the transition zone due to the combined effects of phase transitions, forming a complex truncated cone shape. (3) The Mj-Pv phase transition greatly enhances the plume penetration capability through 660-km phase boundary, which has a significant influence on the plume dynamics. Our results provide new insights which can be used to better constrain the 660-km discontinuity variations, seismic wave velocity structure and plume dynamics in the mantle transition zone. The model can also help to estimate the mantle temperature and Clapeyron slopes at the 660 km phase boundary.
DS202110-1625
2021
Jia, X.Lu, Z., Zhao, H., Wang, Y., Fang, S., Cai, Z., Wang, Z., Ma, H-a., Chen, L., Jia, H., Jia, X.Diamond growth and characteristics in the metal-silicate-H2O-C system at HPHT conditions.Lithos, Vol. 404-405, 106470, 11p. PdfMantlediamond crystals

Abstract: The detailed phase composition and characteristics of diamond crystals grown in the metal-silicate-H2O-C system at 5.5 GPa and 1385 °C are reported in this paper. The conversion efficiency of the graphite-to-diamond in the metal-silicate-C system is lower than that in the metal-C system, which significantly decreases the growth rate of crystal. As the Mg2Si3O8•5H2O content increases to 1.5 wt%, growth pits and {110} related features of trigonal pyramids, skeletal structure, rhombic dodecahedron, and {110} dendrites exhibit in sequence. Simultaneously, the content of graphite and metal inclusions inside the crystal increases. These systematic changes are accompanied by the appearance of Csingle bondH, Csingle bondO, and Cdouble bondO bonds and a decrease of nitrogen content from ?210 ppm to ?60 ppm. It is speculated that H2O will further decompose and bond with carbon atoms and finally enter the diamond structure. The formation of Csingle bondH and Cdouble bondO bonds will terminate the extension of the three-dimensional network of Csingle bondC bonds. These defects will accumulate along the [111] direction and form {110} related characteristics. These chemical bonds also compete with the nitrogen in the system during entering into the diamond lattice. Our experimental model may provide implications for the morphology and formation environment of natural diamonds.
DS200512-1231
2005
Jia, X.P.Zang, C.Y., Jia, X.P., Ma, H.A., Tian, Y., Xiao, H.Y.Effect of regrown graphite on the growth of large gem diamonds by temperature gradient method.Chinese Physics Letters , Vol. 22, 9, pp. 2415-2417.TechnologyDiamond morphology
DS201902-0325
2018
Jia, X-P.Su, L-X., Zhao, C-X., Lou, Q., Chun-Yao, F., Li, Z., Shen, C-L., Zang, J-H., Jia, X-P., Shan, C-X.Efficient phosphorescence from synthetic diamonds.Carbon, Vol. 130, 1, pp. 384-389.Globalsynthetics

Abstract: Synthetic diamonds have inspired much interest for their unique photophysical properties and versatile potential applications, but their phosphorescent phenomenon and mechanism have been paid much less attention. Here, phosphorescent diamonds with a lifetime of 5.4?s were synthesized by high-pressure and high-temperature method, and the diamonds exhibit an emission band at around 468?nm under the excitation wavelength of 230?nm. The quantum yield of the phosphorescent diamonds is about 4.7% at ambient temperature and atmosphere, which is the first report on the quantum yield of diamonds. The unique phosphorescence emission can be attributed to the radiative recombination from iron related donors and boron related acceptors.
DS2003-0657
2003
Jia, Y.Jia, Y., Kerrich, R., Gupta, A.K., Fyfe, W.S.15 N enriched Gondwana lamproites, eastern India: crustal N in the mantle sourceEarth and Planetary Science Letters, Vol. 215, 1-2, pp. 43-56.IndiaLamproites
DS200412-0916
2003
Jia, Y.Jia, Y., Kerrich, R., Gupta, A.K., Fyfe, W.S.15 N enriched Gondwana lamproites, eastern India: crustal N in the mantle source.Earth and Planetary Science Letters, Vol. 215, 1-2, pp. 43-56.IndiaLamproite
DS201012-0872
2010
Jia, Y.Yang, J., Zhang, Z., Xu, X., Li, Y., Li, J., Jia, Y., Liu, Z., Ba, D.Diamond in the Purang peridotite Massif, west of the Yarlung Zangbu Suture, Tibet: a new discovery.Goldschmidt 2010 abstracts, abstractAsia, TibetPurang Massif
DS201507-0319
2015
Jia, Y.Jia, Y., Kerrich, R.N isotope composition of the primitive mantle compared to diamonds.Lithos, Vol. 233, pp. 131-138.MantleNitrogen - subduction
DS1990-1285
1990
Jiaju LiRuyuan Zhang, Hirajima, T., Banno, S., Ishiwatari, A., Jiaju Li, BolinCoesite -eclogite from Donghai area, Jiangsu Province in ChinaInternational Mineralogical Association Meeting Held June, 1990 Beijing China, Vol. 2, extended abstract p. 923-924ChinaEclogite, Coesite
DS200512-1027
2005
Jian, P.Song, S., Zhang, L., Niu, Y., Su, L., Jian, P., Liu, D.Geochronology of diamond bearing zircons from garnet peridotite in the North Qaidam UHPM belt, Northern Tibetan Plateau: a record of lithospheric subduction.Earth and Planetary Science Letters, Vol. 234, 1-2, pp. 99-118.Asia, TibetGeochronology
DS200612-1507
2006
Jian, P.Wang, Q., Wyman, D.A., Xu, J-F., Zhao, Z-H., Jian, P., Xiong, X-L., Bao, Z-W., Li, C-F., Bai, Z-H.Petrogenesis of Cretaceous adakitic and shoshonitic igneous rocks in the Luzong area, Anhui Province: implications for geodynamics and Cu-Au mineralization.Lithos, In pressChinaShoshonites - not specific to diamond
DS200712-0635
2006
Jian, P.Liu, D., Jian, P., Kroner, A., Xu, S.Dating of prograde metamorphic events deciphered from episodic zircon growth in rocks of the Dabie Sulu UHP complex, China.Earth and Planetary Science Letters, Vol. 250, 3-4, Oct. 30, pp. 650-666.ChinaUHP
DS200712-1133
2007
Jian, P.Wang, Q., Wyman, D.A., Xu, J., Jian, P., Zhao, Z., Li, C., Xu, W., Ma, J., He, B.Early Cretaceous adakitic granites in the northern Dabie Complex, central China: implications for partial melting and delamination of thickened lower crust.Geochimica et Cosmochimica Acta, Vol. 71, 10, May 15, pp. 2609-2636.ChinaUHP - Dabie Shon
DS1996-0685
1996
Jian, X.Jian, X., Olea, R.A., Yu, Y.Semivariogram modeling by weighted least squaresComputers and Geosciences, Vol. 22, No. 4, pp. 379-386GlobalComputer, Program -semi variograM.
DS201112-0484
2010
Jian, Y-H.Jian, Y-H., Jiang, S-Y., Ling, H-F.Petrogenesis and tectonic implications of Late Jurassic shoshonitic lamprophyre dikes from the Liaodong Peninsula, NE China.Mineralogy and Petrology, Vol. 100, pp. 127-151.ChinaLamprophyre
DS201312-0405
2013
Jian, Z.Hua, C., Zhili, Q., Taijin, L., Stern, R., Stachel, T., Yuan, S., Jian, Z., Jie, K., Shyu, P., Shecai, Q.Variations in carbon isotopic composition in the subcontinental lithospheric mantle beneath the Yangtze and North Chin a cratons; evidence from in-situ analysis of diamonds using SIMS.Chinese Science Bulletin, Vol. 58, 1, pp. 99-107ChinaCraton
DS1992-1707
1992
JiangXu, Shutong, Su W., Liu, YC, Jiang, LLDiamonds from high-pressure metamorphic rocks in eastern Dabie Mountains.*CHIChin. Sci. B., *CHI, Vol. 37, No. 2, January pp. 140-145. # H331ChinaMetamorphic rocks, Dabie Mountains
DS2002-0445
2002
JiangFang, W., Hu, Su, Xio, Ji, JiangOn emplacment ages of lamproite in Zhenyuan County, Guizhon Province, ChinaChina Sciences Bulletin, Vol.47, 10,pp. 874-80.China, GuizhonGeochronology, Lamproites
DS201702-0257
2017
Jiang, C.Yin, Z., Jiang, C., Chen, M., Lu, F., Quanli, C.Inclusions of a-quartz, albite and olivine in a mantle diamond.Gondwana Research, in press available, 29p.ChinaDeposit - Shengli no. 1

Abstract: Mineral inclusions in diamonds have been used to track potential information on the Earth's deep mantle. Here we report results from a detailed study on the mineral inclusions in a ca. 0.28 ct diamond from the Shengli No. 1 kimberlite in Mengyin County, Shandong Province, eastern China. Our study reveals the presence of ?-quartz, albite and olivine in the diamond. At an inferred depth of ca. 165 km for the diamond crystallization, the inclusions of ?-quartz and albite suggest the possible involvement of deep subducted crustal material, traces of which were captured during the diamond growth and magma migration.
DS202001-0034
2019
Jiang, D.Ramstein, G., Godderis, Y., Donnadieu, Y., Sepulchre, P., Fluteau, F., Zhang, Z., Zhang, R., Su, B., Jiang, D., Schuster, M., Besse, J.Some illustrations of large tectonically driven climate changes in Earth history.Tectonics, doi.org/10.1029/ 2019TC005569Mantletectonics

Abstract: For the celebration of the 50th anniversary of the publication of the pioneering papers that established the basis of plate tectonic, this paper was solicited to illustrate the close relation between tectonics and climate. Amongst the large spectrum of interactions that depict how tectonics modified the climate at geological time steps, we choose to illustrate two major issues: (1) How the “tryptic” climate/long?term carbon cycle/tectonics explains the extraordinary glacial episode (717-635 Ma) occurring during Neoproterozoic era? (2) How major tectonic events (i.e., the slow shrinkage of a huge epicontinental sea and the uplift of large mountains ranges in Asia and Africa) drastically changed the climate and shaped the pattern of present?day monsoons systems. This paper is the result of long?standing collaboration with many researchers from different countries.
DS200612-1346
2005
Jiang, F.Speziale, S., Jiang, F., Duffy, T.S.Compositional dependence of the elastic wave velocities of mantle minerals: implications for seismic properties of mantle rocks.American Geophysical Union, Geophysical Monograph, ed. Van der Hilst, Earth's Deep mantle, structure ...., No. 160, pp. 301-320.MantleGeophysics - seismics
DS201911-2547
2019
Jiang, H.McKenzie, N.R., Jiang, H.Earth's outgassing and climatic conditions: the slow burn towards environmental "catastrophies".Elements, Vol. 15, pp. 325-330.Mantlecarbon
DS202009-1676
2020
Jiang, H.Zheng, H., Chen, H., Wu, C., Jiang, H., Gao, C., Kang, Q., Yang, C., Wang, D., Lai, C-K.Genesis of the supergiant Huayangchuan carbonatite-hosted uranium polymetallic deposit in the Qinling orogen, central China.Gondwana Research, Vol. 86, pp. 250-265.ChinaREE

Abstract: The newly-discovered supergiant Huayangchuan uranium (U)-polymetallic deposit is situated in the Qinling Orogen, Central China. The deposit contains economic endowments of U, Nb, Pb, Se, Sr, Ba and REEs, some of which (e.g., U, Se, and Sr) reaching super-large scale. Pyrochlore, allanite, monazite, barite-celestite and galena are the major ore minerals at Huayangchuan. Uranium is mainly hosted in the primary mineral of pyrochlore, and the mineralization is mainly hosted in or associated with carbonatite dikes. According to the mineral assemblages and crosscutting relationships, the alteration/mineralization at Huayangchuan comprises four stages, i.e., pegmatite REE mineralization (I), main mineralization (II), skarn mineralization (III) and post-ore alteration (IV). Coarse-grained euhedral allanite is the main Stage I REE mineral, and the pegmatite-hosted REE mineralization (ca. 1.8 Ga) occurs mostly in the shallow-level of northwestern Huayangchuan, corresponding to the Paleoproterozoic Xiong'er Group volcanic rocks (1.80-1.75 Ga) in the southern margin of North China Block. Carbonatite-hosted Stage II mineralization contributes to the majority of U-Nb-REE-Ba-Sr resources, and is controlled by the Huayangchuan Fault. Stage II mineralization can be further divided into the sulfate mineralization (barite-celestite) (II-A), alkali-rich U mineralization (aegirine-augite + pyrochlore + uraninite + uranothorite) (II-B) and REE (allanite + monazite + chevkinite)-U (pyrochlore + uraninite) mineralization (II-C) substages. Stage II mineralization may have occurred during the Late Triassic Mianlue Ocean closure. Skarn mineralization contributed to the majority of Pb and minor U-REE (uraninite-allanite) resources at Huayangchuan, and is spatially associated with the Late Cretaceous-Early Jurassic (Yanshanian) Huashan and Laoniushan granites. We suggested that hydrothermal fluids derived from the Laoniushan and Huashan granites may have reacted with the Triassic carbonatites, and formed the Huayangchuan Pb skarn mineralization. The mantle-derived Triassic carbonatites may have been fertilized by the U-rich subducting oceanic sediments, and were further enriched through reacting with the Proterozoic U-REE-rich pegmatite wallrocks at Huayangchuan. Ore-forming elements were likely transported in metal complexes (F?, and ), and deposited with the dilution of the complex concentration. This may have formed the distinct vertical mineralization zoning, i.e., sodic fenite-related alkali-U mineralization at depths and potassic fenite-related REE-U mineralization at shallow level.
DS202012-2258
2020
Jiang, H.Zheng, H., Chen, H., Wu, C., Jiang, H., Gao, C., Kang, Q., Yang, C., Wang, D., Lai, C-k.Genesis of the supergiant Huayanchuan carbonatite-hosted uranium-plymetallic deposit in the Qinling Orogen, central China.Gondwana Research, Vol. 86, pp. 250-265. pdfChinadeposit - Huayangchuan

Abstract: The newly-discovered supergiant Huayangchuan uranium (U)-polymetallic deposit is situated in the Qinling Orogen, Central China. The deposit contains economic endowments of U, Nb, Pb, Se, Sr, Ba and REEs, some of which (e.g., U, Se, and Sr) reaching super-large scale. Pyrochlore, allanite, monazite, barite-celestite and galena are the major ore minerals at Huayangchuan. Uranium is mainly hosted in the primary mineral of pyrochlore, and the mineralization is mainly hosted in or associated with carbonatite dikes. According to the mineral assemblages and crosscutting relationships, the alteration/mineralization at Huayangchuan comprises four stages, i.e., pegmatite REE mineralization (I), main mineralization (II), skarn mineralization (III) and post-ore alteration (IV). Coarse-grained euhedral allanite is the main Stage I REE mineral, and the pegmatite-hosted REE mineralization (ca. 1.8 Ga) occurs mostly in the shallow-level of northwestern Huayangchuan, corresponding to the Paleoproterozoic Xiong'er Group volcanic rocks (1.80-1.75 Ga) in the southern margin of North China Block. Carbonatite-hosted Stage II mineralization contributes to the majority of U-Nb-REE-Ba-Sr resources, and is controlled by the Huayangchuan Fault. Stage II mineralization can be further divided into the sulfate mineralization (barite-celestite) (II-A), alkali-rich U mineralization (aegirine-augite + pyrochlore + uraninite + uranothorite) (II-B) and REE (allanite + monazite + chevkinite)-U (pyrochlore + uraninite) mineralization (II-C) substages. Stage II mineralization may have occurred during the Late Triassic Mianlue Ocean closure. Skarn mineralization contributed to the majority of Pb and minor U-REE (uraninite-allanite) resources at Huayangchuan, and is spatially associated with the Late Cretaceous-Early Jurassic (Yanshanian) Huashan and Laoniushan granites. We suggested that hydrothermal fluids derived from the Laoniushan and Huashan granites may have reacted with the Triassic carbonatites, and formed the Huayangchuan Pb skarn mineralization. The mantle-derived Triassic carbonatites may have been fertilized by the U-rich subducting oceanic sediments, and were further enriched through reacting with the Proterozoic U-REE-rich pegmatite wallrocks at Huayangchuan. Ore-forming elements were likely transported in metal complexes (F?, and ), and deposited with the dilution of the complex concentration. This may have formed the distinct vertical mineralization zoning, i.e., sodic fenite-related alkali-U mineralization at depths and potassic fenite-related REE-U mineralization at shallow level.
DS202109-1475
2021
Jiang, J.Jiang, J., Muir, J.M.R., Zhang, F.Vibrational and thermodynamic properties of hydrous iron-bearing lowermost mantle minerals.MDPI Minerals, Vol. 11, 11080885 14p. PdfMantlebridgmanite

Abstract: The vibrational and thermodynamic properties of minerals are key to understanding the phase stability and the thermal structure of the Earth’s mantle. In this study, we modeled hydrous iron-bearing bridgmanite (Brg) and post-perovskite (PPv) with different [Fe3+-H] defect configurations using first-principles calculations combined with quasi-harmonic approximations (QHA). Fe3+-H configurations can be vibrationally stable in Brg and PPv; the site occupancy of this defect will strongly affect its thermodynamic properties and particularly its response to pressure. The presence of Fe3+-H introduces distinctive high-frequency vibrations to the crystal. The frequency of these peaks is configuration dependence. Of the two defect configurations, [Fe?Si+OH?] makes large effects on the thermodynamic properties of Brg and PPv, whereas [V??Mg+Fe?Mg+OH?] has negligible effects. With an expected lower mantle water concentrations of <1000 wt. ppm the effect of Fe3+-H clusters on properties such as heat capacity and thermal expansion is negligible, but the effect on the Grüneisen parameter ? can be significant (~1.2%). This may imply that even a small amount of water may affect the anharmonicity of Fe3+-bearing MgSiO3 in lower mantle conditions and that when calculating the adiabaticity of the mantle, water concentrations need to be considered.
DS200512-1163
2005
Jiang, L.Wallis, S., Tsuboi, M., Suzuki, K., Fanning, M., Jiang, L., Tanaka, T.Role of partial melting in the evolution of the Sulu (eastern China) ultrahigh pressure terrane.Geology, Vol. 33, 2, pp. 129-132.ChinaUHP
DS1998-1300
1998
Jiang, M.Schulze, A., Jiang, M., Ryberg, T., Gao, R.Survey yields dat a on unique metamorphic rock complex in ChinaEos, Vol. 79, No. 36, Sept. 8, p. 429, 433.ChinaGeophysics - seismics, Dabie Shan
DS200512-1210
2004
Jiang, M.Xu, Z., Jiang, M., Yang, J.Mantle structure of Qinghai Tibet Plateau: mantle plume, mantle shear zone and delamination of lithospheric slab.Earth Science Frontiers, Vol. 11, 4, pp. 329-344. Ingenta 1045384775China, TibetSubduction
DS201212-0127
2013
Jiang, M.Cheng, C., Chen, L., Yao, H., Jiang, M., Wang, B.Distinct variations of crustal shear wave velocity structure and radial anisotropy beneath the North Chin a Craton and tectonic implications.Gondwana Research, Vol. 23, 1, pp. 25-38.ChinaTomography
DS200712-0491
2007
Jiang, N.Jiang, N., Liu, Y., Zhou, W., Yang, J., Zhang, S.Derivation of Mesozoic adakitic magmas from ancient lower crust in the North Chin a craton.Geochimica et Cosmochimica Acta, Vol. 71, 10, May 15, pp. 2591-2608.ChinaSubduction
DS201312-0441
2013
Jiang, N.Jiang, N., Guo, J., Chang, G.Nature and evolution of the lower crust in the eastern North Chin a craton: a review.Earth Science Reviews, in press availableChinaCraton
DS202107-1111
2021
Jiang, S.Lu, J., Chen, W., Ying, Y., Jiang, S., Zhao, K.Apatite texture and trace element chemistry of carbonatite-related REE deposits in China: implications for petrogenesis.Lithos, Vol. 398-399, 106276 pdfChinaREE

Abstract: Apatite is a ubiquitous mineral in carbonatites, and incorporates a variety of trace elements including rare earth elements (REEs). In this study, the textural and chemical variations of apatite were examined in order to trace the magmatic and hydrothermal petrogenesis of three carbonatite-related REE deposits: Shaxiongdong, Miaoya, and Bayan Obo. Various apatite textures were revealed by cathodoluminescence and back-scattered electron imaging. Magmatic apatite, which occurs predominantly in samples from Shaxiongdong, is euhedral, and commonly shows oscillatory or growth zonation with a yellow-green luminescent core and a violet luminescent rim. Euhedral to subhedral metasomatic apatite from Miaoya and Bayan Obo has a turbid texture, with the majority of grains associated with exsolved monazite. Hydrothermal apatite from Bayan Obo, typically occurring as aggregates in close association with fluorite and barite, is anhedral, with green or light violet luminescence. The different apatite textures are characterised by distinct trace element compositions. Magmatic apatite contains the highest concentrations of Mn (avg. 457 ppm) and Sr (avg. 18,285 ppm) and is characterised by a steeply inclined REE chondrite-normalised pattern. Metasomatic apatite, which has undergone in situ dissolution-reprecipitation, contains lower Mn (avg. 272 ppm) and Sr (avg. 9945 ppm) concentrations. It is characterised by highly variable REE trends with an La/SmN ratio varying from 0.13 to 5.61, and lower average La/YbN, La/SmN, and Sr/Y ratios (46, 2.2, and 18, respectively) than magmatic apatite. Hydrothermal apatite that was precipitated from a fluid is characterised by convex upward chondrite-normalised REE distributions with the lowest La/YbN, La/SmN, and Sr/Y ratios (13, 0.69, and 5.8, respectively). The average concentrations of Mn and Sr in this apatite are 270 and 6610 ppm, respectively. There are no Eu anomalies (Eu/Eu* = 0.97) in the chondrite-normalised REE plots for any of the analysed apatite samples. The combined textural and compositional variations of apatite in the three deposits reflect diverse magmatic and hydrothermal processes, including: 1) mineral fractionation contributing to core-rim zoning within the Shaxiongdong magmatic apatite; 2) dissolution-reprecipitation inducing monazite precipitation in Miaoya and Bayan Obo metasomatic apatite; and 3) coprecipitation with fluorite and barite from fluids generating the Bayan Obo hydrothermal apatite. A compilation of published apatite compositions from other rock types demonstrates that trace element compositions of apatite can be used to differentiate crystallisation environments and differentiate apatite from other rock types. Apatite from carbonatite has high Sr, REEs, La/YbN, Th/U, and Sr/Y, and no Eu anomaly, compared with apatite from igneous silicate rocks (except ultramafic rocks), and iron-oxide copper gold (IOCG) or iron-oxide apatite (IOA) deposits.
DS202105-0768
2020
Jiang, S. SuJiang, S. Su, H., Xiong, Y., Liu, T., Zhu, K., Zhang, L.Spatial temporal distribution, geological characteristics and ore formation controlling factors of major types of rare metal mineral deposits in China.Acta Geologica Sinica, Vol. 94, 6, pp. 1757-1773.ChinaREE

Abstract: Rare metals including Lithium (Li), Beryllium (Be), Rubidium (Rb), Cesium (Cs), Zirconium (Zr), Hafnium (Hf), Niobium (Nb), Tantalum (Ta), Tungsten (W) and Tin (Sn) are important critical mineral resources. In China, rare metal mineral deposits are spatially distributed mainly in the Altay and Southern Great Xingán Range regions in the Central Asian orogenic belt; in the Middle Qilian, South Qinling and East Qinling mountains regions in the Qilian-Qinling-Dabie orogenic belt; in the Western Sichuan and Bailongshan-Dahongliutan regions in the Kunlun-Songpan-Garze orogenic belt, and in the Northeastern Jiangxi, Northwestern Jiangxi, and Southern Hunan regions in South China. Major ore?forming epochs include Indosinian (mostly 200-240 Ma, in particular in western China) and the Yanshanian (mostly 120-160 Ma, in particular in South China). In addition, Bayan Obo, Inner Mongolia, northeastern China, with a complex formation history, hosts the largest REE and Nb deposits in China. There are six major rare metal mineral deposit types in China: Highly fractionated granite; Pegmatite; Alkaline granite; Carbonatite and alkaline rock; Volcanic; and Hydrothermal types. Two further types, namely the Leptynite type and Breccia pipe type, have recently been discovered in China, and are represented by the Yushishan Nb-Ta- (Zr-Hf-REE) and the Weilasituo Li-Rb-Sn-W-Zn-Pb deposits. Several most important controlling factors for rare metal mineral deposits are discussed, including geochemical behaviors and sources of the rare metals, highly evolved magmatic fractionation, and structural controls such as the metamorphic core complex setting, with a revised conceptual model for the latter.
DS2002-0781
2002
Jiang, S.Y.Jiang, Y.R., Jiang, S.Y., Ling, H.F., Zhou, X.R., Rui, X.J., Yang, W.Z.Petrology and geochemistry of shoshonitic plutons from the western Kunlun OrogenLithos, Vol.63,3-4, pp. 165-187.ChinaShoshonites
DS200612-0642
2006
Jiang, S.Y.Jiang, Y.H., Jiang, S.Y.Geochemical and Sr Nd Pb Hf isotopic compositions of late Jurassic lamprophyre dike swarm, from Liaodong, NE Chin a and implications for lithosphere delamin ation.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 11. abstract only.ChinaGeochronology
DS200612-1615
2006
Jiang, S-Y.Zhou, J-C., Jiang, S-Y.Mesozoic bimodel volcanics in SE China: implications for both upwelling of asthenosphere and mantle crust interactions.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 23. abstract only.ChinaPlume
DS200712-0173
2007
Jiang, S-Y.Chen, L-H., Jiang, S-Y., Hofmann, A.W., Jovanovic, Z., Xie, L-W., Zhou, X-H.Are peridotite xenoliths in Mesozoic plutons inherited from Paleozoic kimberlites?Plates, Plumes, and Paradigms, 1p. abstract p. A166.ChinaNorth China Craton
DS200712-0482
2007
Jiang, S-Y.Jang, Y-H., Jiang, S-Y., LHou, M-L., Ling, H.F., Zhao, K., Ni, P.Geochemistry of Late Mesozoic lamprophyre dikes from the eastern North Chin a Craton: implications for subcontinental lithosphere evolution.Plates, Plumes, and Paradigms, 1p. abstract p. A445.ChinaLamprophyre
DS201012-0325
2010
Jiang, S-Y.Jiang, Y-H., Jiang, S-Y., Ling, H-F., Ni, P.Petrogenesis and tectonic implications of Late Jurassic shoshonitic lamprophyre dikes from the Liaodong Peninsula, NE China.Mineralogy and Petrology, Vol. 100, 3, pp.127-151.ChinaShoshonite
DS201112-0484
2010
Jiang, S-Y.Jian, Y-H., Jiang, S-Y., Ling, H-F.Petrogenesis and tectonic implications of Late Jurassic shoshonitic lamprophyre dikes from the Liaodong Peninsula, NE China.Mineralogy and Petrology, Vol. 100, pp. 127-151.ChinaLamprophyre
DS201312-0561
2014
Jiang, S-Y.Ma, L., Jiang, S-Y., Hofman, A.W., Dai, B-Z., Hou, M-L., Zhao, K-D, Chen, L-H., Jiang, Y.H.Lithospheric and asthenospheric sources of lamprophyres in the Jiadong Peninsula: a consequence of rapid lithospheric thinning beneath the North Chin a craton?Geochimica et Cosmochimica Acta, Vol. 124, pp. 250-271.ChinaLamprophyre
DS201605-0863
2016
Jiang, S-Y.Ma, L., Jiang, S-Y., Hofmann, A.W., Xu, Y-G, Dai, B-Z., Hou, M-L.Rapid lithospheric thinning of North Chin a craton: new evidence from Cretaceous mafic dikes in the Jiaodong Peninsula.Chemical Geology, Vol. 432, pp. 1-15.ChinaDikes

Abstract: The North China Craton is a classic case for the destruction of an ancient craton, in that it records the loss of more than 100 km of ancient refractory lithospheric mantle during the late Mesozoic and early Cenozoic. However, the mechanisms for this lithospheric thinning remain controversial in large part due to the lack of any systematic investigations of the Mesozoic asthenospheric mantle via its derived mafic rocks, which are key to understand the thinning processes. In this paper, we present detailed zircon U-Pb geochronology, elemental geochemistry, and Sr-Nd-Hf isotopic data for lamprophyres and diabase-porphyries of the Jiaodong Peninsula, in the eastern North China Craton in order to place constraints on models for lithospheric thinning. Our results show that the lamprophyres and diabase-porphyries are derived from the convective asthenospheric mantle via different degrees of partial melting, and that this mantle source was previously modified by carbonatitic liquids. Zircon LA-ICP-MS U-Pb dating suggests an emplacement age for these rocks of 123-121 Ma, the earliest evidence for asthenospherically-derived melts in the Jiaodong Peninsula so far. This emplacement age indicates that the thickness of the lithosphere in the Jiaodong Peninsula was relatively thin at that time. Co-occurrence of the asthenospheric and lithospheric mantle-derived mafic rocks as well as high-Mg adakites record a rapid transition from lithospheric to asthenospheric mantle sources, indicating that the lithosphere beneath the Jiaodong Peninsula was rapidly detached just prior to ca. 120 Ma. Lithospheric thinning of the North China Craton may have been initiated from the Jiaodong Peninsula and Bohai Sea and then propagated towards the interior of the craton.
DS201709-2077
2017
Jiang, S-Y.Ying, Y., Chen, W., Lu, J., Jiang, S-Y., Yang, Y.In situ U-Th-Pb ages of the Miaoya carbonatite complex in the South Qinling orogenic belt, central China.Lithos, in press available, 57p.Chinacarbonatite - Miaoya

Abstract: The Miaoya carbonatite complex in the South Qinling orogenic belt hosts one of the largest rare earth element (REE)-Nb deposits in China that is composed of carbonatite and syenite. The emplacement age of the complex and the geochronological relationship between the carbonatite and syenite have long been debated. In this study, in situ U-Th-Pb ages have been obtained for the constituent minerals zircon, monazite and columbite from carbonatite and syenite of the Miaoya complex, together with their chemical and isotopic compositions. In situ trace element compositions for zircon from carbonatite and syenite are highly variable. The zircon displays slightly heavy REE (HREE)-enriched chondrite-normalized patterns with no Eu anomaly and various light REE (LREE) contents. In situ Th-Pb dating for zircon from the Miaoya complex by laser ablation ICP-MS yields ages of 442.6 ± 4.0 Ma (n = 53) for syenite and 426.5 ± 8.0 Ma (n = 23) for carbonatite. Monazite from carbonatite and syenite shows similar chondrite-normalized REE patterns and yields a consistent Th-Pb age of ~ 240 Ma. Based on petrographic and chemical composition, columbite from the carbonatite can be identified into two groups. The columbite dispersed within carbonatite is characterized by slightly LREE-enriched chondrite-normalized REE patterns, whereas columbite associated with apatite is characterized by LREE-depleted trends. Columbite has been further determined to have a weighted mean 206Pb/238U age of 232.8 ± 4.5 Ma (n = 9) using LA-ICP-MS. Detailed geochronological and chemical investigations suggest that there were two major episodes of magmatic/metasomatic activities in the formational history of the Miaoya carbonatite complex. The early alkaline magmatism emplaced in the Silurian was related to the opening of the Mianlue Ocean, whereas the late metasomatism or hydrothermal overprint occurred during the Triassic South Qinling orogeny. The latter serves as the major ore formation period for both REE (e.g., monazite) and Nb (e.g., columbite).
DS201809-2009
2018
Jiang, S-Y.Chen, W., Lu, J., Jiang, S-Y., Ying, Y-C., Liu. Y-S.Radiogenic Pb reservoir contributes to the rare earth element (REE) enrichment in South Qinling carbonatites.Chemical Geology, Vol. 494, pp. 80-95.Chinacarbonatites

Abstract: Carbonatite and related alkaline silicate rocks contain one of the most significant rare earth element (REE) reserves in the world. It is well-known that these REE deposits are characterized by a strong light REE enrichment with a steep fractionation from La to Lu in the chondrite-normalized diagram. However, the origin of their REE enrichment remains debatable. The Shaxiongdong (SXD) carbonatite in the South Qinling orogenic belt hosts one of the most important REE deposits in central China. In this study, in situ chemical and isotopic data have been obtained for carbonate minerals from the complex. Our results show that calcite has variable trace element abundances, especially REEs. In situ Pb isotope data for calcite reveal extreme variations of 206Pb/204Pb (18.05-31.71) and 207Pb/204Pb (15.49-16.36) ratios. Interestingly, Pb isotope variations display positive correlations with REE enrichments [i.e., (La/Yb)N and (La/Nd)N]. Calcite with extreme radiogenic Pb isotopic compositions displays upper mantle C and O isotopic compositions (?13Cavg?=??5.74‰, ?18Oavg?=?7.13‰) and depleted 87Sr/86Sr isotopic ratios (~0.7030). The observed various REE enrichments accompanying the variable Pb isotopic composition within SXD calcite possibly result from a closed-system metasomatic event. The U-bearing mineral (i.e., pyrochlore) accumulating abundant uranogenic lead since their Silurian formation serves as the radiogenic Pb and LREE source for the metasomatism. Alternatively, the chemical and isotopic composition observed might suggest involvement of two mantle sources (PREMA and the distinct radiogenic Pb mantle reservoir).
DS201904-0725
2019
Jiang, S-Y.Chen, W., Ying, Y-C., Bai, T., Zhang, J-J., Jiang, S-Y., Zhao, K-D.In situ major and trace element analysis of magnetite from carbonatite related complexes: implications for petrogenesis and ore genesis.Ore Geology Reviews, Vol. 107, pp. 30-40.Chinacarbonatite

Abstract: Magnetite (Fe3O4) is one of the most common accessory minerals in magmatic rocks, and it can accommodate a wide variety of major, minor and trace elements that can be measured by laser ablation ICP-MS. In this study, we investigate the chemical compositions of magnetite from four carbonatite complexes (Oka, Mushgai Khudag, Hongcheon and Bayan Obo). The minor elements (Mg, Ti, Al, Mn) in magnetite vary significantly both within and between different complexes. High field strength elements (Zr, Hf, Nb, Ta, U, Th) are generally depleted in magnetite from carbonatite complexes, whereas K, Rb, Cs, Ca and P are commonly below detection limits. V and Zn display significant variations from tens to thousands of ppm. Co, Ni and Ga are present in ppm or tens of ppm, whereas Cu, Sr, Y, Ba and Pb are characterized by sub-ppm levels. Mo and Ge are identified at the ppm level, whereas a consistent concentration of 2-5?ppm is observed for Ge. The determined chemical compositions of magnetite from carbonatite complexes are quite distinguishable compared to those formed in silicate and sulfide melts. This is clearly shown using multielement variation diagrams, and the distinct signatures of carbonatite-related magnetite include strong positive anomalies of Mn and Zn and negative anomalies of Cu, Co and Ga. The discriminant diagrams of Ti vs. Zr?+?Hf, Ti vs. Nb?+?Ta and Ni/Cr vs. Ti are applicable for distinguishing magmatic and hydrothermal magnetite in carbonatite-related environments. In addition, the discriminant diagram of Zn/Co vs. Cu/Mo and Cu vs. Zr?+?Hf can be used to distinguish carbonatite-related magnetite from magnetite that formed in other environments.
DS201909-2017
2019
Jiang, S-Y.Bai, T., Chen, W., Jiang, S-Y.Evolution of the carbonatite Mo-HREE deposits in the Lesser Qinling orogen: insights from in situ geochemical investigation of the calcite and sulfate. Huanglongpu, HuangshuianOre Geology Reviews, in press available, 38p. PdfChinacarbonatite
DS202006-0960
2020
Jiang, S-Y.Ying, Y-C., Chen, W., Simonetti, A., Jiang, S-Y., Zhao, K-D.Significance of hydrothermal reworking for REE mineralization associated with carbonatite: constraints from in situ trace element and C-Sr isotope study of calcite and apatite from the Miaoya carbonatite complex (China).Geochimica et Cosmochimica Acta, in press available 45p. PdfChinadeposit - Miaoya

Abstract: A majority of carbonatite-related rare earth element (REE) deposits are found in cratonic margins and orogenic belts, and metasomatic/hydrothermal reworking is common in these deposits; however, the role of metasomatic processes involved in their formation remains unclear. Here, we present a comprehensive in situ chemical and isotopic (C-Sr) investigation of calcite and fluorapatite within the Miaoya carbonatite complex located in the South Qinling orogenic belt, with the aim to better define the role of late-stage metasomatic processes. Carbonatite at Miaoya commonly occurs as stocks and dykes intruded into associated syenite, and can be subdivided into equigranular (Type I) and inequigranular (Type II) calcite carbonatites. Calcite in Type I carbonatite is characterized by the highest Sr (up to ?22,000?ppm) and REE (195-542?ppm) concentrations with slight LREE-enriched chondrite normalized patterns [(La/Yb)N?=?2.1-5.2]. In situ C and Sr isotopic compositions of calcite in Type I carbonatite define a limited range (87Sr/86Sr?=?0.70344-0.70365; ?13C?=??7.1 to ?4.2 ‰) that are consistent with a mantle origin. Calcite in Type II carbonatite has lower Sr (1708-16322?ppm) and REEs (67-311?ppm) and displays variable LREE-depleted chondrite normalized REE patterns [(La/Yb)N?=?0.2-3.3; (La/Sm)N?=?0.2-2.0]. In situ 87Sr/86Sr and d13C isotopic compositions of Type II calcite are highly variable and range from 0.70350 to 0.70524 and ?7.0 to ?2.2 ‰, respectively. Fluorapatite in Type I and Type II carbonatites is characterized by similar trace-element and isotopic compositions. Both types of fluorapatite display variable trace element concentrations, especially LREE contents, whereas they exhibit relatively consistent near-chondritic Y/Ho ratios. Fluorapatite is characterized by consistent Sr isotopic compositions with a corresponding average 87Sr/86Sr ratio of 0.70359, which suggests that fluorapatite remained relatively closed in relation to contamination. The combined geochemical and isotopic data for calcite and fluorapatite from the Miaoya complex suggest that carbonatite-exsolved fluids together with possible syenite assimilation during the Mesozoic metasomatism overprinted the original trace-element and isotopic signatures acquired in the early Paleozoic magmatism. Hydrothermal reworking resulted in dissolution-reprecipitation of calcite and fluorapatite, which served as the dominant source of REE mineralization during the much younger metasomatic activity. The results from this study also suggest that carbonatites located in orogenic belts and cratonic edges possess a great potential for forming economic REE deposits, especially those that have undergone late-stage metasomatic reworking.
DS2002-1777
2002
Jiang, W.Zhang, L., Ellis, D.J., Jiang, W.Ultra high pressure metamorphism in western Tianshan, China: part I. Evidence from inclusions of coesite pseudomorphs in garnet and from quartz exsolution lamellae iAmerican Mineralogist, Vol. 87, pp. 853-60.ChinaUHP - mineralogy, Eclogites
DS2002-1778
2002
Jiang, W.Zhang, L., Ellis, D.J., Williams, S., Jiang, W.Ultra high pressure metamorphism in western Tianshan, China: part II. Evidence from magnesite in eclogite.American Mineralogist, Vol. 87, pp. 861-66.ChinaUHP - mineralogy, Eclogites
DS2003-1546
2003
Jiang, W.Zhang, L., Ellis, D.J., Arculus, R.J., Jiang, W., Wei, C.Forbidden zone subduction of sediments to 150 km depth - the reaction of dolomite toJournal of Metamorphic Geology, Vol. 21, 6, pp. 523-30.ChinaSubduction, UHP
DS200412-2205
2003
Jiang, W.Zhang, L., Ellis, D.J., Arculus, R.J., Jiang, W., Wei, C.Forbidden zone subduction of sediments to 150 km depth - the reaction of dolomite to magnesite + aragonite in the UHPM metapelitJournal of Metamorphic Geology, Vol. 21, 6, pp. 523-30.ChinaSubduction, UHP
DS200612-0038
2006
Jiang, W.Arnadottir, T., Jiang, W., Feigl, K.L., Geirsson, H., Sturkell, E.Kinematic models of plate boundary deformation in southwest Iceland derived from GPS observations.Journal of Geophysical Research,, Vol. 111, B7, B7402Europe, Iceland, mantleGeophysics - seismics
DS1996-1105
1996
Jiang, X.Peltier, W.R., Jiang, X.Glacial isostatic adjustment and Earth rotation: refined constraints on the viscosity of deepest mantle.Journal of Geophysics Research, Vol. 101, No. 2, Feb. 10, pp. 3269-90.MantleGeophysics -seismics, Geomorphology -glacial isostasy
DS200512-0478
2005
Jiang, X.Jiang, X.Mapping the deep lithospheric structure beneath the eastern margin at the Tibetan Plateau from gravity anomalies.Journal of Geophysical Research, Vol. 110, B7, 10.1029/2004 JB003394AsiaGeophysics - seismics
DS200512-0479
2005
Jiang, X.Jiang, X., Jin, Y.Mapping the deep lithospheric structure beneath the eastern margin of the Tibetan Plateau from gravity anomalies.Journal of Geophysical Research, Vol. 110, B7, B07407 10.1029/2004 JB003394Asia, TibetGeophysics - gravity
DS202110-1624
2021
Jiang, X.Long, Z-Y., Yu, X-Y., Jiang, X., Guo, B-J., Ma, C-Y., You, Y., Zheng, Y-Y.Fluid boiling and fluid-rock interaction as primary triggers for emerald deposition: insights from the Dayakou emerald deposit ( China).Ore Geology Reviews, Vol. 139, 104454, 15p. PdfChinaemerald

Abstract: The formation of tectonic magmatic-related emerald deposits necessarily invokes a mixing model of Be-rich granitic rocks and Cr and/or V-rich surrounding rocks. However, there has been continuing debate on the deposit genesis, with the essential controversy being the relative significance of magma versus metamorphism in mineralizing as well as the key triggers for emerald deposition. The Dayakou emerald deposit genetically related to the Cretaceous granitic magmatism and hosted within the Neoproterozoic metasedimentary rocks is an ideal study case to probe into the above outstanding issue. In this paper, three hydrothermal mineralization and related alteration stages have been recognized in Dayakou, comprised of the greisenization and early emerald mineralization in high-temperature hydrothermal condition (stage-I; peak at 380 °C to 480 °C), the silicification and main emerald mineralization in medium-high temperature fluid (stage-II; peak at 300 °C to 360 °C) and the late carbonate alteration and scheelite mineralization (stage-III). Analysis results of fluid inclusion and C-H-O isotopes of emeralds and associated minerals suggest that ore-forming fluids belong to the H2O-NaCl ± CO2 system with minor H2S, CH4, and N2, exsolved from the Cretaceous granites and gradually interacted with the surrounding metamorphic rocks. We combine the new data with those reported in earlier studies to further propose a genesis scenario for the Dayakou deposit, in which Be-bearing fluids originally exsolved from peraluminous melts and fluoride complexes may be an effective transport proxy for Be in hydrothermal fluids. Fluid boiling during fluid ascent leads to the significant fractionation and enrichment of elements and the escape of volatiles (e.g., HF, H2O, CO2) in ore system. Meanwhile, sustained fluid-rock interaction (e.g., greisenization) increasingly extracts Cr, V and Ca into fluids to facilitate mineral precipitation, wherein the crystallization of fluoride minerals would cause the destabilization of Be-F complexes. Our study indicates that fluid boiling and fluid-rock interactions are the primary triggers for emerald deposition.
DS200612-0642
2006
Jiang, Y.H.Jiang, Y.H., Jiang, S.Y.Geochemical and Sr Nd Pb Hf isotopic compositions of late Jurassic lamprophyre dike swarm, from Liaodong, NE Chin a and implications for lithosphere delamin ation.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 11. abstract only.ChinaGeochronology
DS201312-0561
2014
Jiang, Y.H.Ma, L., Jiang, S-Y., Hofman, A.W., Dai, B-Z., Hou, M-L., Zhao, K-D, Chen, L-H., Jiang, Y.H.Lithospheric and asthenospheric sources of lamprophyres in the Jiadong Peninsula: a consequence of rapid lithospheric thinning beneath the North Chin a craton?Geochimica et Cosmochimica Acta, Vol. 124, pp. 250-271.ChinaLamprophyre
DS2002-0781
2002
Jiang, Y.R.Jiang, Y.R., Jiang, S.Y., Ling, H.F., Zhou, X.R., Rui, X.J., Yang, W.Z.Petrology and geochemistry of shoshonitic plutons from the western Kunlun OrogenLithos, Vol.63,3-4, pp. 165-187.ChinaShoshonites
DS201012-0325
2010
Jiang, Y-H.Jiang, Y-H., Jiang, S-Y., Ling, H-F., Ni, P.Petrogenesis and tectonic implications of Late Jurassic shoshonitic lamprophyre dikes from the Liaodong Peninsula, NE China.Mineralogy and Petrology, Vol. 100, 3, pp.127-151.ChinaShoshonite
DS1992-1704
1992
Jiang LailiXu Shutong, Jiang Laili, Liu Yican, Zhang YongTectonic framework and evolution of the Dabie Mountains in Anhui, EasternChina.Acta Geologica Sinica, Vol. 5, No. 3, September pp. 221-238.ChinaTectonics, Coesite, diamonds
DS1991-0797
1991
Jiang MeiJiang Mei, Ma KaiyiThe magnetic lineament map of Chin a and adjacent sea areasGlobal tectonics and Metallogeny, Vol. 3, No. 4, July, pp. 193-211ChinaStructure -lineament, Geophysics -magnetics
DS1986-0407
1986
Jiang RongJiang Rong, Deng Chujun, Liu WanyuMining geology of the Mwadui diamond deposit in Tanganyika with Special reference to research methodson satellite minerals of diamonds.*CHIBulletin. Institute Mineral Deposits Chinese Academy of Geol. Sciences, *CHI, Vol. 1, No. 19, pp. 25-87GlobalDeposit -Mwadui, Remote sensing
DS1997-0557
1997
Jianghai, Wang et al.Jianghai, Wang et al.Geological and geochemical evidence for discriminating anatectic and subsolidus migmatites Dabie Shan Complex.Chinese Journal of Geochem. (eng), Vol. 16, No. 2, pp. 112-22.China, Hubeimetamorphism, Deposit - Dabie Shan area
DS2000-1037
2000
Jiangqing Ji.Yan Liu, Zhong, D., Jiangqing Ji.Carbonatites in the eastern Himalayan syntaxis: a direct evidence for mantle magma upwelling Neogene ...Igc 30th. Brasil, Aug. abstract only 1p.India, HimalayasCarbonatite
DS2002-0945
2002
Jianguo, D.Lianxing, G.,Jianguo, D., et al.Composition of phengites in eclogites and their retrogressive derivatives of Dabie shan region: implication for the applicability of phengite geobarometre....Chinese Journal of Geochemistry, Vol. 21, 1, pp.52-56.ChinaGeochemistry
DS2002-1749
2002
Jianhua, C.H.Xu, Y., Liu, F., Jianhua, C.H.Crust and upper mantle structure beneath western Chin a from P wave travel time tomography.Journal of Geophysical Research, Oct. 29, 10.1029/2001JB000402.ChinaGeophysics - seismics
DS1989-1658
1989
JianjunWu, Jianjun, Mereu, R.F.A combined P-S wave and gravity interpretation of thedat a from the Kapuskasking experimentGeological Association of Canada (GAC) Annual Meeting Program Abstracts, Vol. 14, p. A102. (abstract.)OntarioTectonics, Kapuskasing Lithoprobe
DS1993-1790
1993
JianjunYang, Jianjun, Godard, G., Kienast, J-R., Yongzheng Lu, JinxiongUltrahigh pressure ( 60 Kbar) magnesite-bearing garnet peridotites from northeastern Jiangsu, China.Journal of Geology, Vol. 101, No. 5, September pp. 541-554.ChinaEclogites, Shandong Province
DS1987-0320
1987
Jianjun WuJianjun Wu, Mereu, R.F.Analysis of the results of the Kapuskasing seismic experimentEos, abstractOntarioTectonics
DS1990-0762
1990
Jianjun WuJianjun Wu, Mereu, R.F.The nature of the Kapuskasing structural zone: results from the 1984seismic refraction experimentExposed cross sections of the Continental Crust, ed. M.H. Salisbury and, pp. 563-586OntarioKapuskasing zone, Tectonics
DS1992-0790
1992
Jianjun WuJianjun Wu, Mereu, R.F.Crustal structure of the Kapuskasing Uplift from Lithoprobe nearvertical/wide angle seismic reflection dataJournal of Geophysical Research, Vol. 97, No. B12, November 10, pp. 17, 411-17, 453OntarioGeophysics -seismics, LITHOPROBE.
DS1992-0791
1992
Jianjun WuJianjun Wu, Mereu, R.F.Crustal structure of the Kapuskasing uplift from LITHOPROBE near vertical/wide angle seismic reflection dataJournal of Geophysical Research, Vol. 97, No. B12, November 10, pp. 17, 441-17, 453OntarioKapuskasing Zone, Lithoprobe
DS1992-0792
1992
Jianjun WuJianjun Wu, Mereu, R.F., Percival, J.A.Seismic image of the Ivan hoe Lake fault zone in the Kapuskasing uplift Of the Canadian shieldGeophysical Research Letters, Vol. 19, No. 4, February 21, pp. 353-360OntarioStructure -fault, Geophysics -seismics
DS200612-1115
2006
Jianli, S.Qicheng, F., Jianli, S., Ping, X., Qian, S., Tuanhua, W.Si and alkali rich melt inclusions in minerals of mantle peridotites from eastern China: implications for lithospheric evolution.Science China Earth Sciences, Vol. 49, 1, Jan. pp. 43-49.ChinaPeridotite - melting
DS2003-1556
2003
JianminZhaochong, Z., Jingwen, M., Robinson, P.T., Zhou, M.F., Guochao, Z., JianminThe Aoyougou mafic ultramafic complex in the North Qilian Mountains northwestInternational Geology Review, Vol. 45, 9, pp. 841-856.China, northwestMagmatism
DS200412-2221
2003
Jianmin, Y.Zhaochong, Z., Jingwen, M., Robinson, P.T., Zhou, M.F., Guochao, Z., Jianmin, Y., Zhiliang, W., Zuoheng, Z.The Aoyougou mafic ultramafic complex in the North Qilian Mountains northwest China: a possible middle Proterozoic ophiolite aloInternational Geology Review, Vol. 45, 9, pp. 841-856.ChinaMagmatism
DS1992-0455
1992
Jianpin ZhengFengxiang Lu, Lei Zhao, Jianpin ZhengPaleozoic mantle characteristics beneath North Chin a PlatformProceedings of the 29th International Geological Congress. Held Japan August 1992, Vol. 1, abstract p. 178-179. cont'dChinaShengli No. 1 pipe, Kimberlite, diamond inclusions
DS1995-0885
1995
Jianping, L.Jianping, L., Kornprobst, J., Vielzeuf, D.An improved experimental calibration of the olivine spinel geothermometerChinese Journal of Geochemistry, Vol. 14, No. 1, pp. 68-77.GlobalGeothermometry, Olivine -spinel calibration
DS1997-0558
1997
Jianping, L.Jianping, L., O'Neill, H. St., Seifert, F.Experimental study on the solubility of Cr2 in olivine, orthopyroxene and spinel solid solutions.Chinese Journal of Geochem. (Eng.), Vol. 16, No. 2, pp. 139-47.GlobalPetrology - experimental, Olivine
DS1995-1120
1995
Jianping, Z.Lu Fengxiang, Jianping, Z., et al.Paleozoic lithospheric mantle composition and processes beneath North ChinaPlatformProceedings of the Sixth International Kimberlite Conference Abstracts, pp. 336-338.ChinaMantle xenoliths, Deposit -Yanggao, Menyin, Fuxian, Hebi, Shexian
DS1996-0452
1996
Jianping, Z.Fengziang, L., Jianping, Z., Lie, Z.Geochemistry of kimberlite in North Chin a PlatformInternational Geological Congress 30th Session Beijing, Abstracts, Vol. 1, p. 115.ChinaGeochemistry, Kimberlite
DS1998-0417
1998
Jianping, Z.Fengziantq, L., Ying, W., Jianping, Z.Geochemical characteristics and emplacement ages of the Menghyinkimberlites, Shandong Province.International Geology Review, Vol. 40, No. 11, Nov. pp. 998-1007.China, ShandongGeochemistry, genesis, Deposit - Menghyin
DS2000-0290
2000
Jianping, Z.Fengxiang, L., Ying, W., Meihuam C., Jianping, Z.Geochemical characteristics and emplacement ages of the Mengyin kimberlites,Shandong Province.Snyder, Neal, Ernst, Plan. Petrology and Geochemistry, pp. 74-82.China, ShandongGeochemistry, Deposit - Mengyin
DS200612-1553
2006
Jiantang, P.Xianwu, B., Ruizhong, H., Jiantang, P., Li, L., Kaixing, W., Wenchao, S.Geochemical characteristics of the Yaoan and Machangqing alkaline rich intrusions in the Ailaoshan Jinshajiang belt, western Yunnan, China.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 1, abstract only.ChinaAlkalic
DS2002-0782
2002
Jianxin, Z.Jingsui, Y., Zhiqin, X., Jianxin, Z., Shugang, S.Early Paleozoic North Qaidam UHP metamorphic belt on the north eastern Tibetan plateau and a paired subduction model.Terra Nova, Vol. 14, 5, Oct. pp. 397-404.China, TibetUHP - Ultrahigh pressure, subduction
DS200612-0643
2006
Jianxin, Z.Jianxin, Z., Fancomg, M.Lawsonite bearing eclogites in the north Qilian and north Altyn Tagh: evidence for cold subduction of oceanic crust.Chinese Science Bulletin, Vol. 51, 10, May pp. 1238-1244.ChinaEclogite
DS200712-0492
2006
Jianxin, Z.Jianxin, Z., Jingsui, Y., Fabcong, M.,Yusheng, W., Huimin, Li., Cailai, W.U Pb isotopic studies of eclogites and their host gneisses in the Xitishan area of the North Qaidam mountains, western China: new evidence HP-UHP belt.Journal of Asian Earth Sciences, Vol. 28, 2-3, Nov. 15, pp. 143-150.ChinaUHP, Eclogites
DS1993-0751
1993
Jian-xin ZhaoJian-xin Zhao, McCulloch, M.T.Melting of a subduction modified continental lithospheric mantle: evidence from Late Proterozoic mafic dike swarms in central AustraliaGeology, Vol. 21, No. 5, May pp. 463-466AustraliaDike, Subduction
DS200612-1612
2006
Jianxiong, Z.Zhenyu, C., Yuchuan, C., Denghong, W., Jue, X., Jianxiong, Z.Rutiles in eclogites from the Sulu UHPM terrane: a preliminary study.Maor & Bierlein eds. Understanding ore systems through precise geochronology, isotope tracing, microgeochem., Chapter 7-36, pp.861-864.ChinaUHP
DS1991-0798
1991
Jianxiong ZhouJianxiong Zhou, Griffin, W.L., Jaques, A.L., Ryan, C.G., Win, T.T.Geochemistry of indicator minerals from Chinese kimberlites andlamproitesProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 475-477ChinaPyrope, chromite, ilmenite, LIMA, yimengite, Proton microprobe, EMP
DS1994-1982
1994
Jianzong Z., Wuyi W.Zhang Andi, Dehuan, X., Xiling, X., Lihe, G., Jianzong Z., Wuyi W.The status and future of diamond exploration in ChinaProceedings of Fifth International Kimberlite Conference, Vol. 2, pp. 268-284.ChinaDiamond exploration, Review
DS201412-0485
2014
Jiao, J.J.Kuang, X., Jiao, J.J.An integrated permeability - depth model for Earth's crust.Geophysics Research Letters, Vol. 41, pp. 7539-7545.MantleGeophsyics - seismics
DS200712-1184
2007
Jiao, W-F.Wu, Y-B., Gao, S., Zhang, H-F., Wang, S-H., Jiao, W-F., Liu, Y-S, Yuan, H-L.Timing of UHP metamorphism in the Hongan area, western Dabie Mountains China: evidence from zircon Pb age, trace element and Hf isotope composition.Contributions to Mineralogy and Petrology, Vol. 155, 1, pp. 123-133.ChinaUHP
DS201112-0802
2011
Jiasheng, Z.Piper, J.D.A., Jiasheng, Z., Huang, B., Roberts, A.P.Paleomagnetism of Precambrian dyke swarms in the North Chin a shield: the ~1.8 Ga LIP event and crustal consolidation in late Paleoproterozoic times.Journal of Asian Earth Sciences, Vol. 41, 6, pp. 504-524.ChinaPangea supercontinent
DS1992-0468
1992
JiaweiFitches, W.R., Fletcher, C.J.N., Jiawei, XuGeotectonic relationships between cratonic blocks in E. Chin a and KoreaJournal of Southeast Asian Earth Science, Vol. 6, No. 3-4, pp. 185-199China, KoreaTectonics, Craton
DS201711-2532
2017
Jicha, B.Trela, J., Gazel, E., Sobolev, A.V., Moore, L., Bizimis, M., Jicha, B., Batanova, V.G.The hottest lavas of the Phanerozoic and the survival of deep Archean reservoirs.Nature Geoscience, Vol. 10, pp. 451-456.Mantlegeodynamics - plumes

Abstract: Large igneous provinces and some hotspot volcanoes are thought to form above thermochemical anomalies known as mantle plumes. Petrologic investigations that support this model suggest that plume-derived melts originated at high mantle temperatures (greater than 1,500?°C) relative to those generated at ambient mid-ocean ridge conditions (about 1,350?°C). Earth’s mantle has also cooled appreciably during its history and the temperatures of modern mantle derived melts are substantially lower than those produced during the Archaean (2.5 to 4.0 billion years ago), as recorded by komatiites (greater than 1,700?°C). Here we use geochemical analyses of the Tortugal lava suite to show that these Galapagos-Plume-related lavas, which formed 89 million years ago, record mantle temperatures as high as Archaean komatiites and about 400?°C hotter than the modern ambient mantle. These results are also supported by highly magnesian olivine phenocrysts and Al-in-olivine crystallization temperatures of 1,570 ± 20?°C. As mantle plumes are chemically and thermally heterogeneous, we interpret these rocks as the result of melting the hot core of the plume head that produced the Caribbean large igneous province. Our results imply that a mantle reservoir as hot as those responsible for some Archaean lavas has survived eons of convection in the deep Earth and is still being tapped by mantle plumes.
DS1994-0846
1994
Jichun SunJichun Sun, Murrell, S.A.F.On the growth and collapse of wide orogenic beltsGeophys. Journal of Int, Vol. 118, pp. 255-268GlobalOrogeny, Tectonics
DS1990-1630
1990
JieZhao, Xixi, Coe, R.S., Zhou Yaoxiu, Wu Haoruo, Wang, JieNew paleomagnetic results from northern China: collision and suturing with Siberia and KazakhstanTectonophysics, Vol. 181, pp. 43-81China, RussiaGeophysics, Paleomagnetics
DS201312-0405
2013
Jie, K.Hua, C., Zhili, Q., Taijin, L., Stern, R., Stachel, T., Yuan, S., Jian, Z., Jie, K., Shyu, P., Shecai, Q.Variations in carbon isotopic composition in the subcontinental lithospheric mantle beneath the Yangtze and North Chin a cratons; evidence from in-situ analysis of diamonds using SIMS.Chinese Science Bulletin, Vol. 58, 1, pp. 99-107ChinaCraton
DS2003-0304
2003
Jiliang, L.Cunningham, D., Owen, L., Snee, L.W., Jiliang, L.Structural framework of a major transcontinental orogenic termination zone: the extremeJournal of the Geological Society of London, Vol. 160, 4, July pp. 575-590.ChinaTectonics - not specific to diamonds
DS200412-0392
2003
Jiliang, L.Cunningham, D., Owen, L., Snee, L.W., Jiliang, L.Structural framework of a major transcontinental orogenic termination zone: the extreme easternmost Tien Shan, China.Journal of the Geological Society, Vol. 160, 4, July pp. 575-590.ChinaTectonics - not specific to diamonds
DS1950-0399
1958
Jillson, W.R.Jillson, W.R.A Bibliography of Elliott County, KentuckyFrankfort, Kentucky: Perry Publishing Co., 28P.United States, Appalachia, KentuckyKimberley, Geology
DS1960-0561
1965
Jillson, W.R.Jillson, W.R.Geology of the Glencairn and Pine Ridge Faults in Western Wolf County, Kentucky.Selection Trust Exploration Ltd., International UNPUBL. Report, APRIL 20TH. 15P.United States, Appalachia, KentuckyGeology, Tectonics
DS1960-0562
1965
Jillson, W.R.Jillson, W.R.Discovery of Mid-paleozoic Faulting in Eastern-central Kentucky.Frankfort, Kentucky: Roberts Printing Co., 13P.United States, Appalachia, KentuckyGeology, Tectonics, Regional
DS1960-0563
1965
Jillson, W.R.Jillson, W.R.Biangular Faulting in the Outer Blue grass Region of Northeastern Kentucky.Frankfort, Kentucky: Roberts Printing Co., 26P.United States, Appalachia, KentuckyTectonics, Geology
DS1975-0694
1978
Jilyaeva, V.A.Bocharova, G.I., Garanin, V.K., Jilyaeva, V.A., Kudryavtseva, G.New Dat a on Exolution Lamellae in Picroilmenites from Jakutia Kimberlite Pipes.Jeol. News, Vol. 16E, No. 1, PP. 18-24.Russia, YakutiaMineralogy, Genesis, Kimberlite
DS200812-0265
2008
Jimack, P.K.Davies, C.J., Gubbins, D., Willis, A.P., Jimack,P.K.Time averaged paleomagnetic field and secular variation: prediction from dynamo solutions based on lower mantle seismic tomography.Physics of the Earth and Planetary Interiors, Vol. 169, 1-4, pp. 194-203.MantleGeophysics - seismics
DS201811-2596
2015
Jimenez, J.F.Ochoa, C.J.C., Herreno Daza, M.J., Fortaleche, D., Jimenez, J.F.Progress on the study of parameters related to the origin of Colombian diamonds.InColor, December pp. 88-97.South America, Colombiaemeralds
DS202004-0525
2019
Jimenez-Munt, I.Kumar, A., Fernandez, M., Jimenez-Munt, I., Torne, M., Verges, J., Afonso, J.C.LitMod2D_2.0: an improved integrated geophysical petrological modeling took for the physical interpretation of upper mantle anomalies.Geochemistry, Geophysics, Geosystems, 10.1029/2019GC008777. 19p.Mantlegeophysics

Abstract: LitMod2D integrates geophysical and petrological data sets to produce the thermal, density, and seismic velocity structure of the lithosphere and upper mantle. We present a new LitMod2D_2.0 package with improvements focused on (i) updated anelastic attenuation correction for anharmonic seismic velocities, (ii) chemical composition in the sublithospheric mantle, and (iii) incorporation of sublithospheric mantle anomalies. Sublithospheric mantle anomalies can be defined with different chemical composition, temperature, seismic velocities, and a combination of them, allowing the application of LitMod2D_2.0 to regions affected by mantle upwelling, subduction, delamination, and metasomatism. We demonstrate the potential application of LitMod2D_2.0 to such regions and the sensitivity of thermal and compositional anomalies on density and seismic velocities through synthetic models. Results show nonlinearity between the sign of thermal and seismic velocity anomalies, and that S wave velocities are more sensitive to temperature whereas P wave velocities are to composition. In a synthetic example of subduction, we show the sensitivity of sublithospheric mantle anomalies associated with the slab and the corner flow on surface observables (elevation, geoid height, and gravity anomalies). A new open?source graphic user interface is incorporated in the new package. The output of the code is simplified by writing only the relevant physical parameters (temperature, pressure, material type, density, and seismic velocities) to allow the user using predefined post?processing codes from a toolbox (flexure, mineral assemblages, synthetic passive seismological data, and tomography) or designing new ones. We demonstrate a post?processing example calculating synthetic seismic tomography, Rayleigh surface?wave dispersion curves, and P wave receiver functions from the output file of LitMod2D_2.0.
DS1997-0961
1997
Jiminez, M et al.Robin, C., Hall, M., Jiminez, M et al.MojAnd a volcanic comple: development of two adjacent contemporaneous volcanoes with contrasting eruptive ..Journal of South American Earth Sci, Vol. 10, No. 5-6, pp. 345-59EcuadorMagma suites, Geodynamics, geochemistry, volcanics
DS202008-1396
2020
Jiminez-Franco, A.Gonzales-Jiminez, J.M., Tassara, S., Schettino, E., Roque-Rosell, J., Farre-de-Pablo, J., Saunders, J.E., Deditius, A.P., Colas, V., Rovira-Medina, J.J., Guadalupe Davalos, M., Schilling, M., Jiminez-Franco, A., Marchesi, C., Nieto, F., Proenza, J.A., GerMineralogy of the HSE in the subcontinental lithospheric mantle - an interpretive review.Lithos, in press available, 44p. PdfMantleHSE

Abstract: The highly siderophile elements (HSE: Os, Ir, Ru, Rh, Pt, Pd, Re, Au) exist in solid solution in accessory base-metal sulfides (BMS) as well as nano-to-micron scale minerals in rocks of the subcontinental lithospheric mantle (SCLM). The latter include platinum-group minerals (PGM) and gold minerals, which may vary widely in morphology, composition and distribution. The PGM form isolated grains often associated with larger BMS hosted in residual olivine, located at interstices in between peridotite-forming minerals or more commonly in association with metasomatic minerals (pyroxenes, carbonates, phosphates) and silicate glasses in some peridotite xenoliths. The PGM found inside residual olivine are mainly Os-, Ir- and Ru-rich sulfides and alloys. In contrast, those associated with metasomatic minerals or silicate glasses of peridotite xenoliths consist of Pt, Pd, and Rh bonded with semimetals like As, Te, Bi, and Sn. Nanoscale observations on natural samples along with the results of recent experiments indicate that nucleation of PGM is mainly related with the uptake of HSE by nanoparticles, nanominerals or nanomelts at high temperature (> 900?°C) in both silicate and/or sulfide melts, regardless of the residual or metasomatic origin of their host minerals. A similar interpretation can be assumed for gold minerals. Our observations highlight that nanoscale processes play an important role on the ore-forming potential of primitive mantle-derived magmas parental to magmatic-hydrothermal deposits enriched in noble metals. The metal inventory in these magmas could be related with the physical incorporation of HSE-bearing nanoparticles or nanomelts during processes of partial melting of mantle peridotite and melt migration from the mantle to overlying continental crust.
DS1990-0763
1990
JinJin, Yuegin, Taylor, L.A.Mantle and crustal xenoliths from a South Pacifichotspot: a fun visit toTaihiti Society IslandsGeological Society of America (GSA) Abstract Volume, Held Tuscaloosa, Alabama, April, Vol. 22, No. 4, p. 20. abstract onlyGlobalXenoliths, Hotspot
DS1994-1421
1994
JinQu Qi, Beard, B.L., Jin, Taylor, L.A.Petrology and geochemistry of aluminium augite and chromium diopside group mantle xenoliths from Tahiti, Society Islands.International Geology Review, Vol. 36, No. 2, February pp. 152-178.GlobalXenoliths, Petrology
DS1996-0687
1996
JinJin, Bai, Fengyan, DaiThe early Precambrian crustal evolution of ChinaJournal of Southeast Asian Earth Sciences, Vol. 13, No. 3/5, pp. 205-214ChinaPrecambrian, Structure, tectonics
DS2001-0355
2001
JinGao, S., Kern, H., Jin, Popp, Jin, Zhang, ZhangPoisson's ratio of eclogite: the role of retrogressionEarth and Planetary Science Letters, Vol. 192, No. 4, pp. 523-31.GlobalEclogite - geochemistry, Poisson ratio
DS2001-0355
2001
JinGao, S., Kern, H., Jin, Popp, Jin, Zhang, ZhangPoisson's ratio of eclogite: the role of retrogressionEarth and Planetary Science Letters, Vol. 192, No. 4, pp. 523-31.GlobalEclogite - geochemistry, Poisson ratio
DS1996-0686
1996
Jin, B.Jin, B., Fengyan, D.The early Precambrian crustal evolution of ChinaJournal of Southeast Asian Earth Sciences, Vol. 12, No. 3-4 pp.205-214.ChinaTectonics, Archean
DS200812-0658
2008
Jin, C.Li, S., Jin, C., Dai, L., Liu, X., Zhou, X.Thermochronological constraints to two stage Indonesian extrusion of the HP UHP terranes in the Dabie Sulu orogen, central Chine.Goldschmidt Conference 2008, Abstract p.A544.ChinaUHP
DS201601-0004
2015
Jin, J.Bancroft, A.M., Brunton, F.R., Kleffner, M.A., Jin, J.Silurian condodont biostratigraphy and carbon isotope stratigraphy of the Victor mine core in the Moose River basin.Canadian Journal of Earth Sciences, Vol. 52, 12, pp. 1169-1181.Canada, Ontario, AttawapiskatDeposit - Victor

Abstract: The Moose River Basin in Ontario, Canada, contains nearly 1 km of Silurian marine strata, and although it has been studied for more than a century, its precise correlation globally has not been constrained. Herein, a core from the Victor Mine in the Moose River Basin was examined for conodont biostratigraphy and carbonate carbon (?13Ccarb) isotope chemostratigraphy to provide a detailed chronostratigraphic framework for the Silurian strata (Severn River, Ekwan River, and Attawapiskat formations) in the Moose River Basin. The recovery of Aspelundia expansa, Aspelundia fluegeli fluegeli, Distomodus staurognathoides, Ozarkodina polinclinata estonica, Pterospathodus eopennatus, and Aulacognathus bullatus, as well as the lower Aeronian, upper Aeronian, lower Telychian (Valgu), and ascending limb of the Sheinwoodian (Ireviken) positive carbonate carbon (?13Ccarb) isotope excursions provide significantly improved chronostratigraphic correlation of Llandovery strata in the Moose River Basin. Silurian Conodont Biostratigraphy and Carbon (?13Ccarb) Isotope Stratigraphy of the Victor Mine (V-03-270-AH) Core in the Moose River Basin.
DS1992-0598
1992
Jin, S.Graebner, J.E., Jin, S., Kammlott, G.W., Herb, J.A., Gardiner, C.F.Large anisotropic thermal conductivity in synthetic diamond filmsNature, Vol. 359, No. 6394, October 1, pp. 401-402GlobalDiamond synthesis, CVD.
DS1999-0358
1999
Jin, S.Kern, H., Gao, S., Jin, S.Petrophysical studies on rocks from the Dabie ultrahigh pressure metamorphic belt: implications for compositionTectonophysics, Vol. 301, No. 3-4, Jan. 30, pp. 191-216.ChinaCrust - petrology, metamorphism
DS2001-0537
2001
Jin, S.Jin, Z.M., Zhang, J., Green, H.W., Jin, S.Eclogite rheology: implications for subducted lithosphereGeology, Vol. 29, No. 8, Aug. pp. 667-70.ChinaGarnet, subduction, ultra high pressure (UHP), Dabie Shan
DS202108-1313
2021
Jin, S.Wang, C., Zhang, Z., Xie, Q., Cheng, Z., Kong, W., Liu, B., Santosh, M., Jin, S.Olivine from aillikites in the Tarim large igneous province as a window into mantle metasomatism and multi-stage magma evolution.American Mineralogist, Vol. 106, pp. 1064-1076.Chinametasomatism

Abstract: Aillikites are carbonate-rich ultramafic lamprophyres, and although they are volumetrically minor components of large igneous province (LIP), these rocks provide important clues to melting and meta-somatism in the deep mantle domain during the initial stages of LIPs. In this study, we investigate the Wajilitag “kimberlites” in the northwestern part of the Tarim LIP that we redefine as hypabyssal aillikites based on the following features: (1) micro-phenocrystic clinopyroxene and Ti-rich andradite garnet occurring in abundance in the carbonate-rich matrix; (2) Cr-spinel exhibiting typical Fe-Ti enrichment trend also known as titanomagnetite trend; and (3) olivine showing dominantly low Mg values (Fo < 90). To constrain the magma source and evolution, the major, minor, and trace element abundance in olivine grains from these rocks were analyzed using electron microprobe and laser ablation-inductively coupled plasma-mass spectrometry. Olivine in the aillikites occurs as two textural types: (1) groundmass olivines, as sub-rounded grains in matrix, and (2) macrocrysts, as euhedral-anhedral crystals in nodules. The groundmass olivines show varying Mg (Fo89-80) with high-Ni (1606-3418 ppm) and Mn (1424-2860 ppm) and low-Ca (571-896 ppm) contents. In contrast, the macrocrysts exhibit a restricted Fo range but a wide range in Ni and Mn. The former occurs as phenocrysts, whereas the latter are cognate cumulates that formed from earlier, evolved aillikite melt. The two olivine populations can be further divided into sub-groups, indicating a multi-stage crystallization history of the aillikite melt. The crystallization temperatures of groundmass olivines and macrocrysts in dunite nodules as computed from the spinel-olivine thermometers are 1005-1136 and 906-1041 °C, respectively. The coupled enrichment of Ca and Ti and lack of correlation between Ni and Sc and Co in the olivine grains suggest a carbonate-silicate metasomatized mantle source. Moreover, the high 100•Mn/Fe (average 1.67) at high Ni (up to 3418 ppm), overlapping with OIB olivine, and the 100•Ni/Mg (~1) of primitive Mg-Ni-rich groundmass olivines suggest a mixed source that involved phlogopite- and carbonate-rich metasomatic veins within mantle peridotite.
DS201201-0854
2011
Jin, X-M.Lee, K.C., Sprague, M.R., Sussman, B.J., Nunn, J., Langford, N.K., Jin, X-M., Champoin, T., et al.Entangling microscopic diamonds at room temperature. ( quantum technology)Science, Vol. 334, no. 6060, Dec. 2, pp. 1253-1256.TechnologyQuantum state of diamonds
DS200512-0479
2005
Jin, Y.Jiang, X., Jin, Y.Mapping the deep lithospheric structure beneath the eastern margin of the Tibetan Plateau from gravity anomalies.Journal of Geophysical Research, Vol. 110, B7, B07407 10.1029/2004 JB003394Asia, TibetGeophysics - gravity
DS1996-0688
1996
Jin, Yu.Jin, Yu., McNutt, M.K., Zhu, Y-S.Mapping the descent of Indian and Eurasian plates beneath the Tibetan Plateau from gravity anomalies.Journal of Geophysical Research, Vol. 101, No. 5, May 10, pp. 1275-90.IndiaGeophysics -gravity, Tectonics
DS200412-2204
2004
Jin, Z.Zhang, J., Green, W.H., Bozhillov, K., Jin, Z.Faulting induced by precipitation of water at grain boundaries in hot subducting oceanic crust.Nature, Vol. 428, April 8, 633-636.MantleSubduction
DS200712-0639
2007
Jin, Z.Liu, L., Zhang, J., Green, H.W.II, Jin, Z., Bozhilov, K.N.Evidence of former stishovite in metamorphosed sediments, implying subduction to > 350 km.Earth and Planetary Science Letters, Vol. 263,3-4, Nov.30, pp. 180-191.MantleUHP
DS200712-0641
2007
Jin, Z.Liu, X., Jin,Z., Green, H.W.Clinoenstatite exsolution in diopsidic augite of Dabie Shan - garnet peridotite from depth of 300 km.Americam Mineralogist, Vol. 92, 4, pp. 546-552.ChinaUHP
DS200912-0446
2009
Jin, Z.Liu, Q., Yang, T., Zeng, Q., Zheng, J., Luo, Y., Qui, N., Xu, H., Jin, Z.Magnetic study of the UHP eclogites from the Chinese Continental Scientific drilling project.Journal of Geophysical Research, Vol. 114, B02106.ChinaUHP
DS201012-0454
2010
Jin, Z.Liu, Q., Zeng, Q., Zheng, J., Yang, T., Qui, N., Liu, Z., Lou, Y., Jin, Z.Magnetic properties of serpentinized garnet peridotites from the CCSD main hole in the Sulu ultrahigh pressure metamorphic belt, eastern China.Journal of Geophysical Research, Vol. 115, B6, B06104ChinaUHP
DS201012-0828
2010
Jin, Z.Wang, C., Jin, Z., Gao, S., Zhang, J., Zheng, S.Eclogite- melt/peridotite reaction: experimental constraints of the destruction mechanism of the North Chin a craton.Science China Earth Sciences, Vol. 53, 6, pp. 797-809.ChinaMelting
DS201212-0822
2012
Jin, Z.Zhao, S., Jin, Z., Zhang, J., Xu, H., Xia, G., Green, H.W.II.Does subducting lithosphere weaken as it enters the lower mantle?Geophysical Research Letters, Vol. 39, L10311 5p.MantleSubduction
DS201607-1322
2016
Jin, Z.Zhang, Y., Wu, Y., Wang, C., Zhu, L., Jin, Z.Experimental constraints on the fate of subducted upper continental crust beyond the depth of no return.Geochimica et Cosmochimica Acta, Vol. 186, pp. 207-225.MantleSubduction, melting

Abstract: The subducted continental crust material will be gravitationally trapped in the deep mantle after having been transported to depths of greater than ?250 -300 km (the “depth of no return”). However, little is known about the status of this trapped continental material as well as its contribution to the mantle heterogeneity after achieving thermal equilibrium with the surrounding mantle. Here, we conduct an experimental study over pressure and temperature ranges of 9 -16 GPa and 1300 -1800 °C to constrain the fate of these trapped upper continental crust (UCC). The experimental results show that partial melting will occur in the subducted UCC along normal mantle geotherm to produce K-rich melt. The residual phases composed of coesite/stishovite + clinopyroxene + kyanite in the upper mantle, and stishovite + clinopyroxene + K-hollandite + garnet + CAS-phase in the mantle transition zone (MTZ), respectively. The residual phases achieve densities greater than the surrounding mantle, which provides a driving force for descent across the 410-km seismic discontinuity into the MTZ. However, this density relationship is reversed at the base of the MTZ, leaving the descended residues to be accumulated above the 660-km seismic discontinuity and may contribute to the “second continent”. The melt is ?0.6 -0.7 g/cm3 less dense than the surrounding mantle, which provides a buoyancy force for ascent of melt to shallow depths. The ascending melt, which preserves a significant portion of the bulk-rock rare earth elements (REEs), large ion lithophile elements (LILEs), and high-filed strength elements (HFSEs), may react with the surrounding mantle. Re-melting of the metasomatized mantle may contribute to the origin of the “enriched mantle sources” (EM-sources). Therefore, the deep subducted continental crust may create geochemical/geophysical heterogeneity in Earth’s interior through subduction, stagnation, partial melting and melt segregation.
DS201611-2149
2016
Jin, Z.Zhang, L., Smyth, J.R., Allaz, J., Kawazoe, T., Jacobsen, S.D., Jin, Z.Transition metals in the transition zone: crystal chemistry of minor element substitution in wadsleyite.American Mineralogist, Vol. 101, pp. 2322-2330.TechnologyWadsleyite

Abstract: As the most abundant solid phase at depths of 410-525 km, wadsleyite constitutes a large geochemical reservoir in the Earth. To better understand the implications of minor element substitution and cation ordering in wadsleyite, we have synthesized wadsleyites coexisting with pyroxenes with 2-3 wt% of either TiO2, Cr2O3, V2O3, CoO, NiO, or ZnO under hydrous conditions in separate experiments at 1300 °C and 15 GPa. We have refined the crystal structures of these wadsleyites by single-crystal X-ray diffraction, analyzed the compositions by electron microprobe, and estimated M3 vacancy concentration from b/a cell-parameter ratios. According to the crystal structure refinements, Cr and V show strong preferences for M3 over M1 and M2 sites and significant substitution up to 2.9 at% at the tetrahedral site (T site). Ni, Co, and Zn show site preferences similar to those of Fe with M1? M3 > M2 > T. The avoidance of Ni, Co, and Fe for the M2 site in both wadsleyite and olivine appears to be partially controlled by crystal field stabilization energy (CFSE). The estimated CFSE values of Ni2+, Co2+, and Zn2+ at three distinct octahedral sites show a positive correlation with octahedral occupancy ratios [M2/(M1+M3)]. Ti substitutes primarily into the M3 octahedron, rather than M1, M2, or T sites. Ti, Cr, and V each have greater solubility in wadsleyite than in olivine. Therefore these transition metal cations may be enriched in a melt or an accessory phase if hydrous melting occurs on upward convection across the wadsleyite-olivine boundary and may be useful as indicators of high-pressure origin.
DS201704-0635
2017
Jin, Z.Liu, P., Massonne, H-J., Zhang, J., Wu, Y., Jin, Z.Intergranular coesite inclusions in dolomite from the Dabie Shan: constraints on the preservation of coesite in UHP rocks.Terra Nova, in press availableChinaCoesite

Abstract: Intergranular coesite is extremely rare in, and bears crucial information on the formation and preservation of, ultrahigh-pressure (UHP) rocks. Here, we report the first occurrence of intergranular coesite in a metasedimentary rock, which occurs in the Ganjialing area in the Dabie Shan, east-central China, and contains abundant coesite inclusions in both garnet and dolomite. We investigated the content of structural water in these minerals with Fourier transform infrared spectroscopy. Our new results undermine the ubiquity of the “pressure-vessel” model and highlight the role of reaction kinetics in preserving coesite due to the availability of water in UHP rocks.
DS201811-2591
2018
Jin, Z.Liu, P., Zhang, J., Massonne, H-J., Jin, Z.Polyphase solid-inclusions formed by interactions between infiltrating fluids and precursor minerals enclosed in garnet of UHP rocks from the Dabie Shan, China.American Mineralogist, Vol. 103, pp. 1663-1673.Chinacoesite

Abstract: Three types of polyphase solid-inclusions (PSIs) with distinct mineral assemblages and micro-structures were found in garnet of an ultrahigh-pressure (UHP) eclogite-vein system from the Dabie Shan, east-central China. Type-1 PSI contains variable volumes of quartz, K-feldspar, plagioclase ± other phases, whereas Type-2 PSI contains variable volumes of quartz, calcite ± other phases. Both types display shapes that are compatible with those of euhedral coesite inclusions. Type-3 PSI always contains a rutile core that is surrounded by plagioclase ± quartz and generally displays the morphology of the rutile core. Variable amounts of K-feldspar are embedded within the plagioclase of Type-3 PSIs. The three PSI types developed fluid-mediated microstructures that include wedge-like offshoot and protrusion textures and inclusion-garnet interfaces controlled by the crystallographic structure of garnet. PSIs in peak minerals of UHP rocks have been previously thought to represent primary supercritical fluid or melt inclusions. Here we propose that the studied PSIs were formed under high-pressure (HP) eclogite-facies conditions during exhumation and represent reaction products between an enclosed mineral, such as coesite and rutile, and external fluids infiltrating the host garnet along fractures that have been healed later on. Two immiscible aqueous fluids (i.e., a siliceous and a carbonaceous) were involved in the formation of these PSIs. The siliceous fluid was rich in various large ion lithophile elements like Cs, Rb, Ba, K, Pb, Li, and Sr, whereas the carbonaceous fluid was rich in Pb and Sr. The new PSI formation mechanism proposed in this study brings significant implications for tracing fluid evolution and post-entrapment modifications of mineral inclusions in HP and UHP metamorphic rocks.
DS201909-2110
2019
Jin, Z.Zhang, Y., Wang, C., Zhu, L., Jin, Z., Li, W.Partial melting of mixed sediment-peridotite mantle source and its implications.Journal of Geophysical Research: Solid Earth, Vol. 124, 7, pp. 6490-6503.Mantleperidotite

Abstract: Subducted sediments play an important role in the transport of incompatible elements back into the Earth's mantle. In recent years, studies of volcanic rocks from Samoan (Jackson et al., 2007, https://doi.org/10.1038/nature06048), NE China (Wang, Chen, et al., 2017, https://doi.org/10.1016/j.epsl.2017.02.028), and Gaussberg, Antarctica (Murphy et al., 2002, https://doi.org/10.1093/petrology/43.6.981), have shown geochemical records of a sediment?influenced mantle source from the deep Earth. However, experimental studies on the partial melting behavior of mixed sediment?peridotite mantle beyond subarc depths are very rare. In this study, we conducted experiments to investigate the partial melting behavior of mixed sediment?peridotite mantle at 4-15 GPa and 1200-1800 °C. The experimental solidi of mixed sediment?peridotite and K?feldspar?peridotite systems (Mixes A and B) cross the hot mantle geotherm at depths of around the X discontinuity (seismic discontinuity, ~300?km depth). The trace element compositions of the corresponding partial melts in Mix A showed similar characteristics to those of the Samoan basaltic lavas, potassic basalts from NE China, and Gaussberg lamproites. Therefore, the experimental results provide a possible explanation for the origin of some unusual mantle?derived volcanic rocks that contain recycled sediment signatures and have very deep origins. At depths of ~300 km (X discontinuity), a mixed sediment?peridotite source was heated by a hot?upwelling mantle and produced enriched melt. The enriched melt may interact with the surrounding mantle before incorporated into the upwelling mantle plume and becoming involved in the origin of some volcanic rocks. The experiments also provide a possible link between the enriched?mantle source in the deep mantle and the X discontinuity.
DS1991-0799
1991
Jin, Z.MJin, Z.M, Green, H.W. II, Borch, R.S., Tingle, T.N.Unusual spinel garnet lherzolite xenoliths from basalts in eastern China:constraints on the late Tertiary thermal structure of the upper mantleProceedings of Fifth International Kimberlite Conference held Araxa June 1991, Servico Geologico do Brasil (CPRM) Special, pp. 212-213ChinaLherzolite xenoliths -analyses, Geochemistry
DS2001-0537
2001
Jin, Z.M.Jin, Z.M., Zhang, J., Green, H.W., Jin, S.Eclogite rheology: implications for subducted lithosphereGeology, Vol. 29, No. 8, Aug. pp. 667-70.ChinaGarnet, subduction, ultra high pressure (UHP), Dabie Shan
DS200612-1579
2006
Jin, Z.M.Yuan, H.L., Gao, S., Rudnick, R.L., Jin, Z.M., Walker, R.J.Re Os evidence for age and origin of peridotites from the Dabie Sulu UHP belt.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 10. abstract only.ChinaUHP, geochronology
DS201012-0829
2010
Jin, Z.M.Wang, L., Jin, Z.M., Kusky, T., Xu, H.J., Liu, X.W.Microfabric characteristics and rheological significance of ultra high pressure metamorphosed jadeite quartzite and eclogite Shuanghe, Dabie Mtns.Journal of Metamorphic Geology, Vol. 28, 2, pp. 163-182.ChinaUHP
DS201112-0141
2011
Jin, Z.M.Cao, Y., Song, S.G., Niu, Y.L., Jung, H., Jin, Z.M.Variation of mineral composition, fabric and oxygen fugacity from massive to foliated eclogites during exhumation of subducted ocean crust in North Qiilian sutureJournal of Metamorphic Geology, Vol. 29, 7, pp. 699-720.ChinaSubduction
DS201712-2735
2017
Jin, Z.M.Wang, L., Wang, S-J., Brown, M., Zhang, J-F., Feng, P., Jin, Z.M.On the survival of intergranular coesite in UHP eclogite.Journal of Metamorphic Geology, in press availableChinaUHP

Abstract: Coesite is typically found as inclusions in rock-forming or accessory minerals in ultrahigh-pressure (UHP) metamorphic rocks. Thus, the survival of intergranular coesite in UHP eclogite at Yangkou Bay (Sulu belt, eastern China) is surprising and implies locally ‘dry’ conditions throughout exhumation. The dominant structures in the eclogites at Yangkou are a strong D2 foliation associated with tight-to-isoclinal F2 folds that are overprinted by close-to-tight F3 folds. The coesite-bearing eclogites occur as rootless intrafolial isoclinal F1 fold noses wrapped by a composite S1-S2 foliation in interlayered phengite-bearing quartz-rich schists. To evaluate controls on the survival of intergranular coesite we determined the number density of intergranular coesite grains per cm2 in thin section in two samples of coesite eclogite (phengite absent) and threee samples of phengite-bearing coesite eclogite (2-3 vol.% phengite), and measured the amount of water in garnet and omphacite in these samples, and also in two samples of phengite-bearing quartz eclogite (6-7 vol.% phengite, coesite absent). As coesite decreases in the mode, the amount of primary structural water stored in the whole rock, based on the nominally anhydrous minerals (NAMs), increases from 107/197 ppm H2O in the coesite eclogite to 157-253 ppm H2O in the phengite-bearing coesite eclogite to 391/444 ppm H2O in the quartz eclogite. In addition, there is molecular water in the NAMs and modal water in phengite. If the primary concentrations reflect differences in water sequestered during the late prograde evolution, the amount of fluid stored in the NAMs at the metamorphic peak was higher outside of the F1 fold noses. During exhumation from UHP conditions, where NAMs became H2O saturated, dehydroxylation would have generated a free fluid phase. Interstitial fluid in a garnet-clinopyroxene matrix at UHP conditions has dihedral angles >60°, so at equilibrium fluid will be trapped in isolated pores. However, outside the F1 fold noses strong D2 deformation likely promoted interconnection of fluid and migration along the developing S2 foliation, enabling conversion of some or all of the intergranular coesite into quartz. By contrast, the eclogite forming the F1 fold noses behaved as independent rigid bodies within the composite S1-S2 foliation of the surrounding phengite-bearing quartz-rich schists. Primary structural water concentrations in the coesite eclogite are so low that H2O saturation of the NAMs is unlikely to have occurred. This inherited drier environment in the F1 fold noses was maintained during exhumation by deformation partitioning and strain localization in the schists, and the fold noses remained immune to grain-scale fluid infiltration from outside allowing coesite to survive. The amount of inherited primary structural water and the effects of strain partitioning are important variables in the survival of coesite during exhumation of deeply subducted continental crust. Evidence of UHP metamorphism may be preserved in similar isolated structural settings in other collisional orogens.
DS201806-1259
2018
Jin, Z.M.Wang, L., Wang, S., Brown, M., Zhang, J., Feng, P., Jin, Z.M.On the survival of intergranular coesite in UHP eclogite.Journal of Metamorphic Geology, Vol. 36, 2, pp. 173-194.MantleUHP

Abstract: Coesite is typically found as inclusions in rock?forming or accessory minerals in ultrahigh?pressure (UHP) metamorphic rocks. Thus, the survival of intergranular coesite in UHP eclogite at Yangkou Bay (Sulu belt, eastern China) is surprising and implies locally “dry” conditions throughout exhumation. The dominant structures in the eclogites at Yangkou are a strong D2 foliation associated with tight?to?isoclinal F2 folds that are overprinted by close?to?tight F3 folds. The coesite?bearing eclogites occur as rootless intrafolial isoclinal F1 fold noses wrapped by a composite S1-S2 foliation in interlayered phengite?bearing quartz?rich schists. To evaluate controls on the survival of intergranular coesite, we determined the number density of intergranular coesite grains per cm2 in thin section in two samples of coesite eclogite (phengite absent) and three samples of phengite?bearing coesite eclogite (2-3 vol.% phengite), and measured the amount of water in garnet and omphacite in these samples, and also in two samples of phengite?bearing quartz eclogite (6-7 vol.% phengite, coesite absent). As coesite decreases in the mode, the amount of primary structural water stored in the whole rock, based on the nominally anhydrous minerals (NAMs), increases from 107/197 ppm H2O in the coesite eclogite to 157-253 ppm H2O in the phengite?bearing coesite eclogite to 391/444 ppm H2O in the quartz eclogite. In addition, there is molecular water in the NAMs and modal water in phengite. If the primary concentrations reflect differences in water sequestered during the late prograde evolution, the amount of fluid stored in the NAMs at the metamorphic peak was higher outside of the F1 fold noses. During exhumation from UHP conditions, where NAMs became H2O saturated, dehydroxylation would have generated a free fluid phase. Interstitial fluid in a garnet-clinopyroxene matrix at UHP conditions has dihedral angles >60°, so at equilibrium fluid will be trapped in isolated pores. However, outside the F1 fold noses strong D2 deformation likely promoted interconnection of fluid and migration along the developing S2 foliation, enabling conversion of some or all of the intergranular coesite into quartz. By contrast, the eclogite forming the F1 fold noses behaved as independent rigid bodies within the composite S1-S2 foliation of the surrounding phengite?bearing quartz?rich schists. Primary structural water concentrations in the coesite eclogite are so low that H2O saturation of the NAMs is unlikely to have occurred. This inherited drier environment in the F1 fold noses was maintained during exhumation by deformation partitioning and strain localization in the schists, and the fold noses remained immune to grain?scale fluid infiltration from outside allowing coesite to survive. The amount of inherited primary structural water and the effects of strain partitioning are important variables in the survival of coesite during exhumation of deeply subducted continental crust. Evidence of UHP metamorphism may be preserved in similar isolated structural settings in other collisional orogens.
DS200812-0521
2008
Jin, Z-H.Jin, Z-H., Johnson, S.E.Magma driven multiple dike propogation and fracture toughness of crustal rocks.Journal of Geophysical Research, Vol. 113, B03206MantleMagmatism - dykes
DS1994-0847
1994
Jin, Z-M.Jin, Z-M., Green, H.W., Shou, Y.Melt topology in partially molten mantle peridotite during ductiledeformation.Nature, Vol. 372, No. 6502, Nov. 10, pp. 164-166.MantleMelting
DS200712-0642
2007
Jin, Z-M.Liu, X-W., Jin, Z-M., Green, H.W.II.Clinoenstatite exsolution in diopsidic augite of Dabieshan: garnet peridotite from depth of 300 km.American Mineralogist, Vol. 92, pp. 546-552.ChinaPeridotite, UHP
DS1992-1709
1992
Jin ZhangXureen Wang, Jin ZhangTwo methods of orthogonally stepwise discrimination and theirapplicationsMathematical Geology, Vol. 24, No. 2, February pp. 203-218GlobalGeostatistics, Discrimination
DS1990-0764
1990
Jinfei WangJinfei Wang, Howarth, P.J.Use of the Hough Transform in automated lineament detectionIeee Transactions Of Geoscience And Remote Sensing, Vol. 28, No. 4, July pp. 561-566OntarioSudbury area, Tectonics-lineaments, Tectonics -lineaments
DS201012-0895
2010
Jing, D.Zhonghua, S., Taijin, L., Mendong, S., Jun, S., Jing, D., Xihuan, Z.2010 coated and fracture filled coloured diamond.The Australian Gemmologist, Vol. 24, 1,TechnologyDiamond filling
DS201511-1894
2014
Jing, D.Zhonghua, S., Taijin, L., Meidong, S., Jun, S., Jing, D., Xikuan, Z.Coated and fracture filled coloured diamond.Australian Gemmologist, Vol. 24, 2, pp. 41-43.TechnologyDiamond morphology
DS200412-0690
2004
Jing, F.Gong, Z., Fei, Y., Dai, F., Zhang, L., Jing, F.Equation of state and phase stability of mantle perovskite up to 140 GPa shock pressure and its geophysical implications.Geophysical Research Letters, Vol. 31, 4, Feb. 28, DOI 1029/2004 GLO19132MantleGeophysics - UHP
DS201907-1553
2019
Jing, J-J.Jing, J-J., Su, B-X., Xiao, Y., Zhang, H-F., Uysal, I., Chen, C., Lin, W., Chu, Y., Saka, S.Reactive origin of mantle harzburgite: evidence from orthopyroxene-spinel association.Lithos, Vol. 342-343, pp. 175-186.Europe, Turkeymelting

Abstract: Harzburgites with high modal orthopyroxene (generally >23?vol%) in Archean craton, mantle wedge and oceanic lithospheric mantle are considered to be produced by the interaction between Si-rich liquids and rocks. However, the absence of samples from continental margin hinders the recognition whether this process is prevalent. Mantle xenoliths entrained in Miocene basalts from the Thrace Basin, the margin of Eurasian continent, are dominated by harzburgites with anomalously high orthopyroxene modes. These orthopyroxene grains closely associate with spinel and occasionally with clinopyroxene. In these orthopyroxene-spinel associations, orthopyroxene grains can be up to 1?cm in diameter and display high Al2O3 contents (1.41-4.61?wt%) and Mg# values (89.6-92.4), while spinel crystals are anhedral and bud-shaped and are commonly foliated, with a wide variation in Cr# values ranging from 7.8 to 52.7. The Fe2+/Fe3+ vs. TiO2 diagram shows lots of these spinels are “magmatic” (i.e. spinel crystallized from melts). The orthopyroxene grains have LREE diverging from the modelled melting trends, indicating possible metasomatism following partial melting. They are present in elongated shape, cutting across olivine grains and also replacing olivine as surrounding rims. Fine-grained olivine is occasionally enclosed in the orthopyroxene-spinel association. We, therefore, propose that the association of orthopyroxene and spinel developed from the melt/fluid-rock interaction. These features indicate mineral phase transformation from olivine to orthopyroxene, which can be expressed by the equation: ‘Mg2SiO4 (Ol)?+?SiO2?=?Mg2Si2O6 (Opx)’. The observed Al-rich rim of spinel and bud-shaped Al-spinel, suggest sufficient amount of Al in the Si-rich liquids. The mechanism involved here is the consumption of olivine to produce orthopyroxene and spinel as in the equation: ‘Mg2SiO4 (Ol)?+?Al2O3?=?MgSiO3 (Opx)?+?MgAl2O4 (Sp)’. The Si and Al were enriched in the percolating liquids. Both the high-Cr# and low-Cr# spinels with ‘magmatic’ features imply the percolating liquids were multi-staged or inhomogeneous Cr contents in the liquids. This melt/fluid-rock interaction may account for the formation of abundant harzburgites with high orthopyroxene modes in the Eurasian continental margin. Thus, it indicates the reacting harzburgites are prevalent in the lithospheric mantle beneath oceanic crust, Archean craton and mantle wedge, as well as in the continental margin.
DS201909-2051
2019
Jing, J-J.Jing, J-J., Su, B-X., Xiao, Y., Zhang, H-F., Uysal, I., Chen, C., Lin, W., Chu, Y., Saka, S.Reactive origin of mantle harzburgite: evidence from orthopyroxene-spinel association.Lithos, Vol. 342-343, pp. 175-186.Mantleharzburgite

Abstract: Harzburgites with high modal orthopyroxene (generally >23?vol%) in Archean craton, mantle wedge and oceanic lithospheric mantle are considered to be produced by the interaction between Si-rich liquids and rocks. However, the absence of samples from continental margin hinders the recognition whether this process is prevalent. Mantle xenoliths entrained in Miocene basalts from the Thrace Basin, the margin of Eurasian continent, are dominated by harzburgites with anomalously high orthopyroxene modes. These orthopyroxene grains closely associate with spinel and occasionally with clinopyroxene. In these orthopyroxene-spinel associations, orthopyroxene grains can be up to 1?cm in diameter and display high Al2O3 contents (1.41-4.61?wt%) and Mg# values (89.6-92.4), while spinel crystals are anhedral and bud-shaped and are commonly foliated, with a wide variation in Cr# values ranging from 7.8 to 52.7. The Fe2+/Fe3+ vs. TiO2 diagram shows lots of these spinels are “magmatic” (i.e. spinel crystallized from melts). The orthopyroxene grains have LREE diverging from the modelled melting trends, indicating possible metasomatism following partial melting. They are present in elongated shape, cutting across olivine grains and also replacing olivine as surrounding rims. Fine-grained olivine is occasionally enclosed in the orthopyroxene-spinel association. We, therefore, propose that the association of orthopyroxene and spinel developed from the melt/fluid-rock interaction. These features indicate mineral phase transformation from olivine to orthopyroxene, which can be expressed by the equation: ‘Mg2SiO4 (Ol)?+?SiO2?=?Mg2Si2O6 (Opx)’. The observed Al-rich rim of spinel and bud-shaped Al-spinel, suggest sufficient amount of Al in the Si-rich liquids. The mechanism involved here is the consumption of olivine to produce orthopyroxene and spinel as in the equation: ‘Mg2SiO4 (Ol)?+?Al2O3?=?MgSiO3 (Opx)?+?MgAl2O4 (Sp)’. The Si and Al were enriched in the percolating liquids. Both the high-Cr# and low-Cr# spinels with ‘magmatic’ features imply the percolating liquids were multi-staged or inhomogeneous Cr contents in the liquids. This melt/fluid-rock interaction may account for the formation of abundant harzburgites with high orthopyroxene modes in the Eurasian continental margin. Thus, it indicates the reacting harzburgites are prevalent in the lithospheric mantle beneath oceanic crust, Archean craton and mantle wedge, as well as in the continental margin.
DS202111-1768
2021
Jing, X.Gong, Z., Evans, D.A.D., Youbi, N., Lahna, A.A., Sodelund, U., Malek, M.A., Wen, B., Jing, X., Ding, J., Boumedhdi, M.A., Ernst, R.E.Reorienting the West African craton in Paleoproterozoic-Msoproterozoic supercontinent Nuna.Geology, Vol. 49, 10, pp. 1171-1176. pdfAfrica, west AfricaNuna

Abstract: The location of the West African craton (WAC) has been poorly constrained in the Paleoproterozoic-Mesoproterozoic supercontinent Nuna (also known as Columbia). Previous Nuna reconstruction models suggested that the WAC was connected to Amazonia in a way similar to their relative position in Gondwana. By an integrated paleomagnetic and geochronological study of the Proterozoic mafic dikes in the Anti-Atlas Belt, Morocco, we provide two reliable paleomagnetic poles to test this connection. Incorporating our new poles with quality-filtered poles from the neighboring cratons of the WAC, we propose an inverted WAC-Amazonia connection, with the northern WAC attached to northeastern Amazonia, as well as a refined configuration of Nuna. Global large igneous province records also conform to our new reconstruction. The inverted WAC-Amazonia connection suggests a substantial change in their relative orientation from Nuna to Gondwana, providing an additional example of large-magnitude cumulative azimuthal rotations between adjacent continental blocks over supercontinental cycles.
DS1989-0712
1989
Jing, Y.Jing, Y., Pan, G., Xia, M., Liang, W., Liou, J.G.Occurrences of abundant eclogites in the DabieMountains, Central SOURCE[ EOSEos, Vol. 70, No. 15, April 11, p. 505. (abstract.)ChinaEclogite
DS1990-0765
1990
Jing, Y.Jing, Y., Pan, G., Xia, M., Wang, X., Liou, J.G., Maruyama, S.Petrology of coesite bearing eclogites from the Dabie Mountains CentralChinaInternational Mineralogical Association Meeting Held June, 1990 Beijing China, Vol. 2, extended abstract p. 864-865ChinaEclogites, Coesite
DS1990-1537
1990
Jing, Y.Wang Xiaomin, Jing, Y., Liou, J.G., Pan, G., Liang, W., Xia, M.Field occurrences and petrology of eclogites from the Dabie Mountains, Anhui, central ChinaLithos, Vol. 25, No. 1-3, November pp. 119-130ChinaEclogites, Dabie Mountains
DS200612-0877
2005
Jing, Z.Matsukage, K.N., Jing, Z., Karato, S.Density of hydrous silicate melt at the conditions of Earth's deep upper mantle.Nature, No. 7067, Nov. 24, pp. 488-491.MantleGeochemistry
DS200812-0522
2008
Jing, Z.Jing, Z., Karato, S-I.Compositional effect on the pressure derivatives of bulk modulus of silicate melts.Earth and Planetary Science Letters, Vol. 272, 1-2, July 30, pp. 429-436.MantleGeochemistry
DS200912-0338
2009
Jing, Z.Jing, Z., Karato, S-I.The density of volatile bearing melts in the Earth's deep mantle: the role of chemical composition.Chemical Geology, Vol. 262, 1-2, May 15, pp. 100-107.MantleMelting
DS202104-0618
2020
Jing, Z.Xu, M., Jing, Z., Bajgain, S.K., Mookherjee, M., Van Orman, J.A., Yu, T., Wang, Y.High pressure elastic properties of dolomite melt supporting carbonate-induced melting in deep upper mantle.Proceedings of the National Academy of Sciences PNAS, Vol. 117, 31, pp. 18285-18291. pdfMantlemelting

Abstract: Deeply subducted carbonates likely cause low-degree melting of the upper mantle and thus play an important role in the deep carbon cycle. However, direct seismic detection of carbonate-induced partial melts in the Earth’s interior is hindered by our poor knowledge on the elastic properties of carbonate melts. Here we report the first experimentally determined sound velocity and density data on dolomite melt up to 5.9 GPa and 2046 K by in-situ ultrasonic and sink-float techniques, respectively, as well as first-principles molecular dynamics simulations of dolomite melt up to 16 GPa and 3000 K. Using our new elasticity data, the calculated VP/VS ratio of the deep upper mantle (?180-330 km) with a small amount of carbonate-rich melt provides a natural explanation for the elevated VP/VS ratio of the upper mantle from global seismic observations, supporting the pervasive presence of a low-degree carbonate-rich partial melt (?0.05%) that is consistent with the volatile-induced or redox-regulated initial melting in the upper mantle as argued by petrologic studies. This carbonate-rich partial melt region implies a global average carbon (C) concentration of 80-140 ppm. by weight in the deep upper mantle source region, consistent with the mantle carbon content determined from geochemical studies.
DS2003-0658
2003
Jing, Z.C.Jing, Z.C., Ning, J.Y., Wang, S.G., Zang, S.X.Dynamic phase boundaries of olivine wadsleyite in subduction zones in the westernGeophysical Research Letters, Vol. 29, 22, Nov. 15, DOI 10.1029/2001GLO13810GlobalSubduction
DS1995-2090
1995
JinghaiXia, Jinghai, Sprowl, D.R.Moho depths in Kansas from gravity inversion assuming exponential densitycontrast.Computers and Geosciences, Vol. 21, No. 2, pp. 237-244.GlobalBasement, Geophysics - gravity
DS201212-0832
2011
Jingjing, S.Zhonghua, S., Taijin, L., Meidong, S., Jun, S., Jingjing, S.High quality synthetic yellow orange diamond emerges in China.The Australian Gemmologist, Vol. 24, 7, July-Sept pp.TechnologySynthetics
DS201511-1895
2014
Jingjing, S.Zhonghua, S., Taijin, L., Meidong, S., Jun, S., Jingjing, S.High quality synthetic yellow orange diamond emerges in China.Australian Gemmologist, Vol. 24, 7, pp. 167-170.ChinaSynthetics
DS2002-0782
2002
Jingsui, Y.Jingsui, Y., Zhiqin, X., Jianxin, Z., Shugang, S.Early Paleozoic North Qaidam UHP metamorphic belt on the north eastern Tibetan plateau and a paired subduction model.Terra Nova, Vol. 14, 5, Oct. pp. 397-404.China, TibetUHP - Ultrahigh pressure, subduction
DS200412-1433
2003
Jingsui, Y.Nicheng, S., Wenji, B., Zhesheng, M., Qingsong, F., Ming, X., Binggang, Y., Mingquan, D., Jingsui, Y.An x ray diffraction study of an inclusion in diamond from the Luobusha chromite deposit in Tibet, China.Acta Geologica Sinica, Vol. 77, 3, pp. 326-331.ChinaDiamond - inclusion
DS200612-0208
2006
Jingsui, Y.Cailai, W., Wooden, J.L., Jingsui, Y., Robinson, P.T., Lingsen, Z., Rendeng, S., Songyong, C.Granitic magmatism in the North Qaidam Early Paleozoic Ultra high pressure metamorphic belt, northwest China.International Geology Review, Vol. 48, 3, pp. 223-240.Asia, ChinaUHP
DS200712-0492
2006
Jingsui, Y.Jianxin, Z., Jingsui, Y., Fabcong, M.,Yusheng, W., Huimin, Li., Cailai, W.U Pb isotopic studies of eclogites and their host gneisses in the Xitishan area of the North Qaidam mountains, western China: new evidence HP-UHP belt.Journal of Asian Earth Sciences, Vol. 28, 2-3, Nov. 15, pp. 143-150.ChinaUHP, Eclogites
DS2003-1556
2003
Jingwen, M.Zhaochong, Z., Jingwen, M., Robinson, P.T., Zhou, M.F., Guochao, Z., JianminThe Aoyougou mafic ultramafic complex in the North Qilian Mountains northwestInternational Geology Review, Vol. 45, 9, pp. 841-856.China, northwestMagmatism
DS200412-2221
2003
Jingwen, M.Zhaochong, Z., Jingwen, M., Robinson, P.T., Zhou, M.F., Guochao, Z., Jianmin, Y., Zhiliang, W., Zuoheng, Z.The Aoyougou mafic ultramafic complex in the North Qilian Mountains northwest China: a possible middle Proterozoic ophiolite aloInternational Geology Review, Vol. 45, 9, pp. 841-856.ChinaMagmatism
DS200712-0980
2006
Jingwen, M.Shihong, T., Tiping, D., Jingwen, M., Yanhe, L., Zhongxin, Y.S, C, O, H isotope dat a and noble gas studies of the Maoniuping LREE deposit, Sichuan Province, China: a mantle connection for mineralization.Acta Geologica Sinica, Vol. 80, 4, pp. 540-549.ChinaAlkaline rocks, rare earths, carbonatite
DS200412-1113
2004
Jinhua, H.Lei, Z., Jinhua, H., Yifei, D., Yulong, L.Assortment of deep mantle fluids and their products in kimberlites from China.Acta Geologica Sinica, Vol. 78, 1, pp. 118-120.ChinaGeochemistry, mineral chemistry
DS200612-1611
2006
Jinjie, Y.Zhenyu, C., Jinjie, Y.Trace elements of rutile in eclogites from Sulu UHPM terrane, China.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 21, abstract only.ChinaUHP, geochemistry
DS200612-0644
2006
Jinlong, M.Jinlong, M., Mingxin, T., Xianren, Y.Characteristics and origins of primary fluids and noble gases in mantle derived minerals from the Yishu area, Shandong Province, China.Science China Earth Sciences, Vol. 49, 1, Jan. pp. 77-87.ChinaMineral chemistry
DS1998-0699
1998
Jinnick, L.Jinnick, L., Chevrot, S., Montagner, J.P.Seismic evidence of flow at base of the upper mantleGeophysical Research. Letters, Vol. 25, No. 11, June 1, pp. 1995-98.MantleGeophysics - seismics
DS2003-1530
2003
Jin-XingYong, X., De Lian Liu, Dai, Jin-XingExtremely h2 rich fluid inclusions in eclogite from the Dabie Shan orogenic belt, EasternJournal of the Geological Society of India, Vol. 61, 1, Jan., pp. 101-102.ChinaUHP
DS1993-1790
1993
JinxiongYang, Jianjun, Godard, G., Kienast, J-R., Yongzheng Lu, JinxiongUltrahigh pressure ( 60 Kbar) magnesite-bearing garnet peridotites from northeastern Jiangsu, China.Journal of Geology, Vol. 101, No. 5, September pp. 541-554.ChinaEclogites, Shandong Province
DS1990-0766
1990
Jiracek, G.R.Jiracek, G.R.Near surface and topographic distortions in electromagnetic inductionSurveys in Geophysics, Vol. 11, No. 2-3 September pp. 163-204GlobalTopography, Geophysics - conductivity
DS1995-0886
1995
Jiracek, G.R.Jiracek, G.R., Haak, V., Olsen, K.H.Methods of investigation: practical magnetotellurics in a continental riftenvironmentContinental Rifts: evolution, structure, tectonics, No. 25, pp. 103-132GlobalGeophysics -magnetotellurics
DS200712-1222
2006
JirenZengqian, H., Lu, Jiren, Lin, ShengzhingHeterogeneity of a plume axis: bulk rock geochemical evidence from picrites and basalts in the Emei large Igneous Province, southwest China.International Geology Review, Vol. 48, 12, pp. 1087-1112.ChinaPicrite
DS200912-0695
2008
Jirose, K.Sinmyo, R., Ozawa, H., Jirose, K., Yasuhara, A., Endo, N., Sata, N., Ohishi, Y.Ferric iron content in (Mg,Fe) SiO3 perovskite and post-perocskite at deep lower mantle conditions.American Mineralogist, Vol. 93, 11/12 pp. 1899-1902.MantlePerovskite
DS1996-0690
1996
JishunJishun, RenThe continental tectonics of ChinaJournal of Southeast Asian Earth Sciences, Vol. 13, No. 3/5, pp. 197-204ChinaTectonics
DS1996-0689
1996
Jishun, B.Jishun, B.The continental tectonics of ChinaJournal of Southeast Asian Earth Sciences, Vol. 12, No. 3-4 pp. 197-204.ChinaTectonics
DS1986-0317
1986
JiugaoGuo, Jiugao, Cai Xiucheng, Deng Huaxing, Chen Feng, Tan Yi MeiNatural type 1B diamonds in diamond placer in Hunan province. *CHIKexue Tongbao, *CHI, Vol. 31, No. 4, pp. 257-261ChinaDiamond morphology
DS1986-0318
1986
JiugaoGuo, Jiugao, Chen Feng, et al.Color of placer diamonds in Hunan province.*CHIKuangwu Xuebao, *CHI, Vol. 6, No.2, pp. 132-138ChinaPlacer, Diamond
DS1992-0937
1992
JiuwuLeung, I.S., Wang, M., Xie, JiuwuSIC microphenocrysts found in newly discovered lamproites in Sichuan, ChinaGeological Society of America (GSA) Abstracts with programs, 1992 Annual, Vol. 24, No. 7, abstract p. A258ChinaLamproites
DS1998-1318
1998
JlSeyler, M., Paquette, Jl, Ceuleneer, G., et al.Magmatic underplating, metamorphic evolution, and ductile shearing in aMesozoic Lower Crustal - unit.Journal of Geology, Vol. 106, No. 1, Jan. pp. 35-58Venezuela, TinaquilloMantle unit, metamorphism
DS1991-0366
1991
J-LDella Ventura, G., Robert, J-L, Beny, J-M.Tetrahedrally coordinated Ti4+ in sythetic Ti-rich potassic richterite:evidence from XRD, FTIR, and Raman studiesAmerican Mineralogist, Vol. 76, pp. 1134-1140GlobalExperimental petrology, Potassic richterite
DS1991-0413
1991
J-LDupuy, C., Mevel, C., Bodinier, J-L, Savoyant, L.Zabargad peridotite: evidence for multistage metasomatism during Red SeariftingGeology, Vol. 19, No. 7, July pp. 722-725GlobalMantle Metasomatism, Peridotites
DS1993-1837
1993
J-LZubieta-Rosseti, D., Huyghe, P., Mascle, G., Mugnier, J-L, Baby, P.Influence de l'heritage ante-devonien au front de la chaine andine (Partiecentrale de la Bolivie).(in French)Comptes Rendus Academy Science Paris, (in French), Tomb. 316, Series II, pp. 951-957BoliviaGeophysics -seismics, Structure
DS1998-0998
1998
J-LMetrich, N., Joron, J-L, Berthier, B.Occurrence of boron rich potassic melts in the Vulsini volcanic district, Evidence from melt inclusions.Geochimica et Cosmochimica Acta, Vol. 62, No. 3, pp. 507-14.ItalyXenoliths
DS1988-0040
1988
J-MBardinet, C., Gabert, G., Monget, J-M, Zheng YuApplication of multisatellite dat a to thematic mapping #2Geol. Jahrb, Vol. 67, Sect. B., 74p. coloured mapsTanzaniaRemote Sensing, Tectonics
DS201212-0595
2012
J-MRolland, Y., Lardeaux, J-M, Jolivet, L.Deciphering orogenic evolution.Journal of Geodynamics, Vol. 56-57, pp. 1-6.MantleTectonics
DS200412-0917
2003
JML Resources Ltd.JML Resources Ltd.Drill program completed at Marten River.JML Resources Ltd., Aporil 8, 1/2p.Canada, OntarioNews item - press release
DS1993-1000
1993
JoMcElhinny, M.W., Lock, JoGlobal paleomagnetic database.. supplement number one: update to 1992Surveys in Geophysics, Vol. 14, No. 3, May pp. 303-GlobalGeophysics, Paleomagnetism
DS202009-1630
2020
Joachimiski, M.Hegner, E., Rajesh, S., Willbold, M., Muller, D., Joachimiski, M., Hofmann, M., Linnemann, U., Zieger, J., Pradeepkumar, A.P.Sediment derived origin of the putatative Munnar carbonatite, South India.Journal of Asian Earth Science, Vol. 200, 104432, 18p. PdfIndiadeposit - Munnar

Abstract: Metacarbonate assemblages in high-grade metamorphic terranes often pose challenges when trying to distinguish between mantle-derived carbonatite and sedimentary carbonate protoliths. We present a study of granulite-facies metacarbonate samples of the putative Munnar carbonatite described as decimeter-thick dikes and veins, and layers of a meter-thick metacarbonate and calc-silicate assemblage, respectively. Thin sections of the metacarbonate dike samples show absence of pyrochlore and ubiquitous scapolite, titanite, wollastonite, and detrital zircons are compatible with impure limestone protoliths. Nd and Sr isotope compositions indicate protoliths with Paleoproterozoic crustal residence times which contrast the mantle sources of Indian and global carbonatites. Trace-element patterns display the characteristics of upper crust, and Ce- and Y-anomalies in a number of samples suggest protolith formation under marine conditions. Carbon and oxygen isotope compositions of the metacarbonate samples interlayered with calc-silicate rocks are similar to those in marine limestone. The metacarbonate dikes, however, show mantle-like compositions which are interpreted as reflecting equilibration with mantle-derived CO2 during granulite-facies metamorphism. The dikes yielded a U-Pb zircon crystallization age of 1020 ± 70 Ma and a cross-cutting quartz syenite, thought to be cogenetic, a magmatic age of 620 ± 35 Ma; the hosting gneiss provided a magmatic age of 2452 ± 14 Ma. We conclude that the layered metacarbonate and calc-silicate rocks represent a former marine limestone and marl sequence and the metacarbonate dikes and veins small-volume melts of crust-derived carbonate-rich sediment.
DS201712-2736
2017
Joachum, K.P.Weis, U., Schwager, B., Stoll, B., Nohl, U., Karlowski, P., Leisgang, I., Zwillich, F., Joachum, K.P.Geostandards and Geoanalytical Research bibliographic review 2016 ( geoanalyses, controls)Geostandards and Geoanalyical Review, Nov. 17, in press availableTechnologyreview

Abstract: This bibliographic review covers the research contained in twenty-one scientific journals with important contributions to geoanalysis and related scientific fields (Table 1, Figure 1). The relevance of well characterised reference materials (RMs) used as calibration materials or quality control samples for precise and accurate analyses is widely known and has often been described, for example, by Jochum and Enzweiler (2014).
DS1997-0912
1997
JoanissePilote, P., Dion, C., Joanisse, David, Machado, KirkhaM.Geochronologie des mineralisations d'affiliation magmatique de l'Abitibi -implications geotectoniques.Quebec Department of Mines, DV97-03, p. 47.QuebecGeochronology, Magmatism - not specifc to diamonds
DS201812-2843
2018
Joao, F.Lunina, O., Glaskov, A.S., Gladkochub, D.P., Joao, F., Karpenko, M.A., Felix, J.T., Koshkarev, D.A., Sklyarov, E.The evolution of the crustal stress state of the Catoca kimberlite pipe area, northeastern Angola. IN RUSGeodynamics and Tectonphysics in RUS, Vol. 9, 3, pp. 827-854. only 1 p. english abstractAfrica, Angoladeposit - Catoca

Abstract: This paper presents the first results of the geostructural and tectonophysical studies of the crustal stress state in the Catoca kimberlite pipe area at the southwestern flank of the Kasai Shield in the northeasternAngola. In the evolution of the crustal stress state, six main stages are distinguished by analyzing the displacements of markers, fold hinges, long axes of boudins, granite dikes of various intrusion phases and kimberlites, as well as fractures with striations. For each of these stages, a dominating horizontal tectonic stress and its orientation is identified. During stage 1 (NW extension and shearing) and at the beginning of stage 2 (NW compression), structures formed in the host rocks in brittle-plastic conditions. The replacement of plastic deformation by faulting could occur about 530-510 Ma ago, when the continental crust ofAfricahad completely formed. Stage 3 (radial, mainly NW extension) and stage 4 (shearing, NW extension, and NE compression) were the most important for kimberlite occurrence: in the Early Cretaceous, radial extension was replaced by shearing. Both stages are related to opening of the central segment of theSouth Atlantic. The main kimberlite magmas occurred during the break-up of the Angola-Brazilian segment of Gondwana. In the course of all the four stages, stress was mainly released by the NE- and E-NE-striking faults and, to a lesser extent, by the NW-striking and latitudinal faults. The initial stage of kimberlite magmatism is associated with the NE- and E-NE-striking faults due to the presence of the Precambrian zones of flow and schistosity, which facilitated the NW-trending subhorizontal extension. Stage 5 (NE compression) began in the second half of the Cretaceous and possibly lasted until the end of the Paleogene, and compression occurred mainly along the NW-striking faults. Regionally, it corresponds to two stages of inversion movements in the southern regions of Africa, during which theAngoladome-shaped uplift emerged and the shoulders of the East African rifts began to take shape. Stage 6 (horizontal extension, mainly in the N-NE direction) is related to the processes that took place in the southern segment of theTanganyikarift and the eastern coast of theAtlantic. Based on the results of our studies, it became for the first time possible to get an idea of the main stages in the evolution of the studied region. Further geostructural measurements and dating of the host rocks will provide for a more precise definition of the proposed stages.
DS1992-0793
1992
Job, R.Job, R.Fullerene maker turns metal into diamondsMaterials Edge, Issue No. 33, February p. 1GlobalFullerene, Experimental diamond
DS200712-0331
2007
Joba, S.Fritsch, E., Massi, L., Rossman, G.R., Hainschwang, T., Joba, S., Dessapt, R.Thermochromic and photochromic behaviour of chameleon diamonds.Diamond and Related Materials, Vol. 16, 2, pp. 401-408 Ingenta 1070685097TechnologyDiamond morphology
DS1990-1347
1990
Jobbins, E.A.Shigley, J.E., Dirlam, D.M., Schmetzer, K., Jobbins, E.A.Gem localities of the 1980's. Diamonds featured pp. 12-14Gems and Gemology, Vol. 26, Spring pp. 4-31GlobalGemstones, Diamond - brief overview
DS1970-0354
1971
Jobidon, G.Mereu, R.F., Jobidon, G.A Seismic Investigation of the Crust and Moho on a Line Perpendicular to the Grenville Front.Canadian Journal of Earth Sciences, Vol. 8, PP. 1553-1583.GlobalMid-continent
DS1993-0380
1993
JobinDumont, R., Kiss, F., Stone, Anderson, Dostaler, JobinAeromagnetic surveys 1992-3. joint ventures -international coloboration MDAGeological Survey of Canada (GSC) Forum 1993, p. E12, F13-14. abstractManitobaGeophysics - magnetics
DS1997-0559
1997
Jobin-Bevans, L.S.Jobin-Bevans, L.S., Halden, N.M., Peck, D.C., CameronGeology and oxide mineralization of the Pipe stone Lake anorthosite ManitobaExploration and Mining Geology, Vol. 6, No. 1, pp. 35-61ManitobaTitanium, Vanadium, rare earths, Deposit - Pipestone Lake
DS201504-0196
2012
Jobst, A.Firsching, M., Muhlbauer, J., Nachtrab, F., Jobst, A.Basis material decomposition a quantitative X-ray imaging method and its application in industrial sorting.International Symposium on Digital Industrial Radiology and computed Tomography, Poster 13, 5p.TechnologyDiamond recovery
DS201112-0053
2011
JochumBallhaus, C., Laurenz, V., Fonseca, R., Munker, C., Albarede, Rohrbach, Schmidt, Jochum, Stoll, Weis, HelmyLate volatile addition to Earth.Goldschmidt Conference 2011, abstract p.475.MantleW and Cr elements
DS1989-0713
1989
Jochum, K.P.Jochum, K.P., Hofmann, A.W.Fingerprinting geological materials using SSMS- commentChemical Geology, Vol. 75, No. 3, March 30, pp. 249-252GlobalGeochemistry, SSMS
DS1989-0714
1989
Jochum, K.P.Jochum, K.P., McDonough, W.F., Palme, H., Spettel, B.Compositional constraints on the continental lithospheric mantle from trace elements in spinel peridotite xenolithsNature, Vol. 340, No. 6234, August 17, pp. 548-550GlobalMantle, Xenoliths
DS1990-1010
1990
Jochum, K.P.McDonough, W.F., Jochum, K.P.Constraints on the composition of the continental lithospheric mantle #1Geological Society of Australia Abstracts, No. 25, No. A12.11 pp. 245. AbstractGlobalXenoliths, Mantle
DS1991-0800
1991
Jochum, K.P.Jochum, K.P., et al.Nb-Th-La in komatiites and basalts: constraints on komatiite petrogenesis and mantle evolutionEarth and Planetary Science Letters, Vol. 107, No. 2, November pp. 272-289MantleKomatiites, Petrogenesis
DS1995-1562
1995
Jochum, K.P.Reischmann, T., Brugmann, G.E., Jochum, K.P., Todt, W.A.Trace element and isotopic composition of baddeleyiteMineralogy and Petrology, Vol. 53, No. 1-3, pp. 155-164.GlobalMineralogy, Baddeleyite
DS1997-0560
1997
Jochum, K.P.Jochum, K.P., Hofmann, A.W.Constraints on earth evolution from antimony in mantle derived rocksChemical Geology, Vol. 139, pp. 39-49MantleChondrite, Basalts
DS1999-0052
1999
Jochum, K.P.Becker, H., Jochum, K.P., Carlson, R.W.Constraints from high pressure veins in eclogites on the composition of hydrous fluids in subduction zones.Chemical Geology, Vol. 160, No. 4, Sept. 2, pp. 291-308.MantleEclogites
DS2000-0071
2000
Jochum, K.P.Becker, H., Jochum, K.P., Carlson, R.W.Trace element fractionation during dehydration of eclogites from high pressure pressure terranes, element fluxesChemical Geology, Vol. 163, No. 1-4, pp. 65-99.Mantleultra high pressure (UHP), melting, Subduction zones
DS200812-0523
2008
Jochum, K.P.Jochum, K.P., Nohl, U.Reference materials in geochemistry and environmental research and the GeoReM database.Chemical Geology, In press available 18p.TechnologySampling - not specific to diamonds
DS201312-0053
2013
Jochum, K-P.Ballhaus, C., Laurenz, V., Munker, C., Fonseca, R.O.C., Albarede, F., Rohrbach, A., Lagos, M., Schmidt, M.W., Jochum, K-P., Stoll, B., Weis, U., Helmy, H.M.The U /Pb ratio of the Earth's mantle - a signature of late volatile addition.Earth and Planetary Interiors, Vol. 362, pp. 237-245.MantleMelting
DS1996-1379
1996
Jochun, K.P.Stolz, A.J., Jochun, K.P., Spettel, B., Hoffmann, A.W.Fluid and melt related enrichment in the subarc mantle: evidence from Niobium-Tantalum variations in island arc basaltsGeology, Vol. 24, No. 7, July, pp. 587-590MantleSubarc subduction, Basalts
DS1996-1180
1996
Jock, S.Revetta, F.A., Jock, S.A detailed gravity map of northern New YorkGeological Society of America (GSA) Abstracts, Vol. 28, No. 3, Feb. p. 93. abstractGlobalGeophysics -gravity
DS1985-0308
1985
Jockush, C.G.JR.Jockush, C.G.JR., Mohrherr, J.Embedding the Diamond Lattice in the Recursively Enumerable truth Table Degrees.Proceedings American MATH. SOCIETY, Vol. 94, No. 1, MAY PP. 123-128.GlobalExperimental Research
DS1992-0794
1992
Jodicke, H.Jodicke, H.Water and graphite in the earth's crust - an approach to interpretation of conductivity modelsSurveys in Geophysics, Vol. 13, pp. 381-407GlobalCrust, Geophysics -models
DS1860-0559
1887
Joefeif.Latchinoff, M.M., Joefeif.Meteorite from Novy Urej Penza SiberiaNature., Dec. 1ST.RussiaMeteorite
DS201803-0456
2018
Joel, L.Joel, L.Erasing a billion years of geologic time across the globe.Eos, doi.org/10.1029/2018E0092065Mantlethermochronology

Abstract: The Great Unconformity "a huge time gap in the rock record" may have been triggered by the uplift of an ancient supercontinent, say researchers using a novel method for dating rocks.
DS201807-1500
2018
Joel, L.Joel, L.Ancient Earth froze over in a geologic instant. Snowball Earth and mentions NWT glaciationSciencemag.org, doi:10.1126/ science.aau4137Mantlegeomorphology
DS201904-0751
2019
Joel, L.Joel, L.Isotope geochemists glimpse Earth's impenetrable interior.EOS, 100, https://doi.org/10.1029 /2019EO117415Mantlegeochemistry

Abstract: Painstaking measurements of isotopes and their relative abundance in rocks have illuminated the hidden inner Earth and our planet’s origins and shadowy past for much of the preceding century.
DS1950-0400
1958
Joel, S.Joel, S.Ace of Diamonds, the Story of Solomon Barnato JoelLondon: Muller., 228P., ILLUS.South AfricaKimberlite, Kimberley, Janlib, Biography
DS1996-0792
1996
Joeleht, A.Kukkonen, I.T., Joeleht, A.Geothermal modelling of the lithosphere in the central Baltic Shield And its southern slope.Tectonophysics, Vol. 255, No. 1/2, pp. 25-Baltic ShieldLithosphere, Geothermometry
DS1988-0329
1988
Joergensen, U.G.Joergensen, U.G.Formations of XE-HL enriched diamond grains in stellar environmentsNature, Vol. 332, No. 6166, pp. 702-705GlobalMeteorites
DS1988-0330
1988
Joffreau, P.O.Joffreau, P.O., Haubner, R., Lux, B.Low-pressure diamond growth on refractory metalsInternational Journal of Refract. Hard Met, Vol. 7, No. 4 December pp. 186-194GlobalDiamond morphology
DS1994-1013
1994
JohanLedru, P., Johan, Milesi, TegyeyMarkers of the last stages of the PaleoProterozoic collision: evidence fora 2 Ga continent involving circum South Atlantic provinces.Pres. Res., Vol. 69, pp. 169-91.Brazil, Gabon, Guiana, French Guiana, West AfricaTectonics
DS1988-0407
1988
Johan, V.Laval, M., Johan, V., Tourliere, B.Mabounie carbonatite: example of the formation of a residual deposit withpyrochlore. (in French)Chron. Recher. Min., (in French), Vol. 56, No. 491, June pp. 125-136GlobalCarbonatite, Phosphate
DS2002-0879
2002
Johan, V.Konopasek, J., Schulmann, K., Johan, V.Eclogite facies metamorphism at the eastern margin of the Bohemian Massif - subduction prior to continental underthrusting?European Journal of Mineralogy, Vol. 14,4,pp. 701-14.EuropeUHP - not specific to diamonds
DS201012-0326
2010
Johan, Z.Johan, Z., Ohnenstetter, D.Zincochromite from the Guaniamo River Diamondiferous placers, Venezuela: evidence of its metasomatic origin.Canadian Mineralogist, Vol. 48, 2, pp. 361-374.South America, VenezuelaMineralogy
DS2001-0538
2001
Johannsen, L.Johannsen, L., Moller, C., Soderlund, U.Geochronology of eclogite facies metamorphism in the Sveconorwegian Province of southwest Sweden.Precambrian Research, Vol. 106, No. 3-4, Mar. 1, pp. 261-76.SwedenEclogites
DS200512-0079
2005
Johannseon, J.M.Bergstrand, S., Scherneck, H.G., Milne, G.A., Johannseon, J.M.Upper mantle viscosity from continuous GPS baselines in Fennoscandia.Journal of Geodynamics, Vol. 39, 2, pp. 91-109.Europe, Finland, Sweden, Baltic ShieldGeophysics - seismics
DS2003-0097
2003
Johannson, B.Belonoshko, A.B., Ahuja,k R., Johannson, B.Stability of the body centered cubic phase of iron in the Earth's inner coreNature, No. 6952, August 28, pp. 1032-4.MantleGeochemistry
DS200412-0132
2003
Johannson, B.Belonoshko, A.B., Ahuja,k R., Johannson, B.Stability of the body centered cubic phase of iron in the Earth's inner core.Nature, No. 6952, August 28, pp. 1032-4.MantleGeochemistry
DS200712-0886
2007
Johannson, L.Rehfeldt, T., Obst, K., Johannson, L.Petrogenesis of ultramafic and mafic xenoliths from Mesozoic basanites in southern Sweden: constraints from mineral chemistry.International Journal of Earth Sciences, Vol. 96, 3, pp. 433-450.Europe, SwedenBasanites, Foidites
DS2003-0659
2003
Johansen, T.A.Johansen, T.A., Digranes, P., Van Schaack, M., Lonne, I.Seismic mapping and modeling of near surface sediments in polar areasGeophysics, Vol. 68, 2, pp. 566-73.GlobalGeophysics - seismics - not specific to diamonds
DS200412-0918
2003
Johansen, T.A.Johansen, T.A.,Digranes, P., Van Schaack, M., Lonne, I.Seismic mapping and modeling of near surface sediments in polar areas,Geophysics, Vol. 68, 2, pp. 566-73.TechnologyGeophysics - seismics - not specific to diamonds
DS2003-0791
2003
Johanson, B.S.Lehtonen, M.L., O'Brien, H.E., Peltonen, P., Johanson, B.S., Pakkanen, L.K.Layered mantle at the edge of the Karelian craton: P-T of mantle xenocrysts and8 Ikc Www.venuewest.com/8ikc/program.htm, Session 6, POSTER abstractFinlandBlank
DS200412-1111
2004
Johanson, B.S.Lehtonen, M.L., O'Brien, H.E., Peltonen, B.S., Johanson, B.S., Pakkanen, L.K.Layered mantle at the Karelian Craton margin: P T of mantle xenocrysts and xenoliths from the Kaavi Kuopio kimberlites, Finland.Lithos, Vol. 77, 1-4, Sept. pp. 593-608.Europe, FinlandLithosphere, thermometry
DS200412-1112
2003
Johanson, B.S.Lehtonen, M.L., O'Brien, H.E., Peltonen, P., Johanson, B.S., Pakkanen, L.K.Layered mantle at the edge of the Karelian craton: P-T of mantle xenocrysts and xenoliths from eastern FIn land kimberlites.8 IKC Program, Session 6, POSTER abstractEurope, FinlandMantle petrology
DS200512-0616
2005
Johanson, B.S.Lehtonen, M.L., Marmo, J.S., Nissinen, A.J., Johanson, B.S., Pakkanen, L.K.Glacial dispersal studies using indicator minerals and till geochemistry around two eastern FIn land kimberlites.Journal of Geochemical Exploration, Vol. 87, 1, Oct. pp. 19-43.Europe, Finland, FennoscandiaKaavi-Kuopio, Kuhmo, geochemistry, Pipe 7, Karelian
DS200512-0617
2005
Johanson, B.S.Lehtonen, M.L., Pakkanen, L.K., Johanson, B.S., Lallukka, H.M.EMP analyses of kimberlite indicator minerals from Pipe 7 and Dyke 16 kimberlites and the basal till surrounding them.Geological Survey of Finland, Open File M 41.2/2005/2.Europe, FinlandGeochemistry
DS200612-0325
2006
JohanssonDelgnacio, C., Muoz, M., Sagredo, J., Fernandez, Santan, S., JohanssonIsotope geochemistry and FOZO mantle component of the alkaline carbonatitic association of Fuerteventura, Canary Islands, Spain.Chemical Geology, Vol. 232, 3-4, pp. 99-113.Europe, Spain, Canary IslandsCarbonatite
DS200712-0019
2007
Johansson, A.Andersson, U.B., Rutanen, HG., Johansson, A., Mansfeld, J., Rimsa, A.Characterization of the Paleoproterozoic mantle beneath the Fennoscandian shield: geochemistry and isotope geology (Nd, Sr) of ~1.8 Ga mafic plutonic rocks ...International Geology Review, Vol. 49, 7, pp. 587-625.Europe, SwedenGeochronology
DS1998-0367
1998
Johansson, B.Dubrovinsky, L., Saxena, S.K., Johansson, B.Theoretical study of the stability of MgSiO3 perovskite in the deepmantle.Geophs. Res. Lett., Vol. 25, No. 23, Dec. 1, pp. 4253-56.MantlePerovskite
DS200512-1002
2005
Johansson, B.Skorodumova, N.V., Belonoshko, A.B., Huang, L., Ahuja, R., Johansson, B.Stability of the MgCO3 structures under lower mantle conditions.American Mineralogist, Vol.90, pp. 1008-1011.MantleCarbon, Liquid outer core, boundary
DS200612-1485
2006
Johansson, B.Vitos, L., Magyati-Kope, B., Ahuja, R., Kollar, J., Grimvall, G., Johansson, B.Phase transformations between garnet and perovskite phases in the Earth's mantle: a theoretical study.Physics of the Earth and Planetary Interiors, Vol. 156, 1-2, pp. 108-116.MantleLower mantle, majorite, geophysics -seismic
DS200712-0468
2007
Johansson, B.Isaev, E.I., Skorodumova, N.V., Ahuja, R., Vekilov, Y.K., Johansson, B.Dynamical stability of Fe-H in the Earth's mantle and core regions.Proceedings of National Academy of Sciences USA, Vol. 104, 22, pp. 9168-9177. IngentaMantleChemistry
DS2002-1416
2002
Johansson, J.M.Scherneck, H-G., Johansson, J.M., et al.BIFROST: observing the three dimensional deformation of FennoscandiaAmerican Geophysical Union, Geodynamics Series, Vol. 29, pp. 69-94.Scandinavia, Finland, Sweden, NorwayGeophysics, tectonics
DS200412-1315
2004
Johansson, J.M.Milne, G.A., Mitrovica, J.X., Scherneck, H.G., Davis, J.L., Johansson, J.M., Koivula, H., Vermeer, M.Continuous GPS measurements of Post glacial adjustment in Fennoscandia: 2. modeling results.Journal of Geophysical Research, Vol. 109, B2, 10.1029/2003 JB002619Europe, FennoscandiaGeophysics -
DS200412-1746
2002
Johansson, J.M.Scherneck, H-G., Johansson, J.M., et al.BIFROST: observing the three dimensional deformation of Fennoscandia.American Geophysical Union, Geodynamics Series, Vol. 29, pp. 69-94.Europe, ScandinaviaGeophysics, tectonics
DS2002-0042
2002
Johansson, L.Andersson, J., Moller, C., Johansson, L.Zircon geochronology of migmatite gneisses along the mylonite zone: a major sveconorwegian terrane boundaryPrecambrian Research, Vol. 114, No. 1-2, pp. 121-47.Norway, Baltic ShieldGeochronology, Craton
DS200712-0887
2007
Johansson, L.Rehfeldt, T., Obst, K., Johansson, L.Petrogenesis of ultramafic and mafic xenoliths from Mesozoic basanites in southern Sweden: constraints from mineral chemistry.International Journal of Earth Sciences, Vol. 96, 3, pp. 433-450.Europe, SwedenBasanites, Foidites
DS1996-0208
1996
John, B.E.Campbell, E.A., John, B.E.Constraints on extension related plutonism from modeling of the Colorado River gravity high.Geological Society of America (GSA) Bulletin., Vol. 108, No. 10, Oct. pp. 1242-55.Basin and RangeGeophysics -gravity
DS2003-0660
2003
John, T.John, T., Schenk, V., Haase, K., Scherer, E., Tembe, F.Evidence for a Neoproterozoic ocean in south central Africa from mid oceanic ridgeGeology, Vol. 31, 3, March pp. 243-6.ZambiaGondwana, suture zones, Rodinia, Geothermometry
DS2003-0661
2003
John, T.John, T., Schenk, V., Haase, K., Scherer, E., Tembo, F.Evidence for a Neoproterozoic ocean in south central Africa from mid ocean ridge typeGeology, Vol. 31, 3, March pp. 243-6.ZambiaEclogites, Geochemistry
DS200412-0919
2003
John, T.John, T., Schenk, V., Haase, K., Scherer, E., Tembo, F.Evidence for a Neoproterozoic ocean in south central Africa from mid ocean ridge type geochemical signatures and pressure temperGeology, Vol. 31, 3, March pp. 243-6.Africa, ZambiaEclogite, Geochemistry
DS200612-0715
2006
John, T.Klemd, R., Gao, J., John, T.Trace element enriched fluids released during slab dehydration: implications for oceanic slab mantle wedge transfer.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 22. abstract only.MantleSubduction
DS200712-0493
2007
John, T.John, T.Reactive fluid flow in slabs - a metamorphic view on the origin of the slab component.Plates, Plumes, and Paradigms, 1p. abstract p. A447.MantleSubduction
DS200712-1213
2007
John, T.Zack, T., John, T.An evaluation of reactive fluid flow and trace element mobility in subducting slabs.Chemical Geology, Vol. 239, 3-4, April 30, pp. 199-216MantleSubduction
DS200812-1019
2008
John, T.Schmidt, A., Weyer, S., John, T., Brey, G.P.Nb Ta systematics of orogenic eclogites.Goldschmidt Conference 2008, Abstract p.A833.MantleEclogite
DS200912-0674
2009
John, T.Schmidt, A., Weyer, S., John, T., Brey, G.P.HFSE systematics of rutile bearing eclogites: new insights into subduction zone processes and implications for the Earth's HPSE budget.Geochimica et Cosmochimica Acta, Vol. 73, 2, pp. 455-468.MantleSubduction
DS201012-0260
2010
John, T.Halama, R., Bebout, G.E., John, T., Schenk, V.Nitrogen recycling in subducted oceanic lithosphere: the record in high and ultrahigh pressure metabasaltic rocks.Geochimica et Cosmochimica Acta, Vol. 74, 5, pp. 1636-1652.MantleUHP
DS201012-0604
2010
John, T.Putnis, A., John, T.Replacement processes in the Earth's crust.Elements, Vol. 6, 3, pp. 159-164.MantleMetasomatism
DS201112-0976
2011
John, T.Smit, M.A., Scherer, E.E., John, T., Janssen, A.Creep of garnet in eclogite: mechanisms and implications.Earth and Planetary Science Letters, Vol. 311, 3-4, pp. 411-419.MantlePetrology
DS201212-0280
2012
John, T.Halama, R., Bebout, G.E., John, T., Scamberlluri, M.Nitrogen recycling in subducted mantle rocks and implications for the global nitrogen cycle.International Journal of Earth Sciences, in press available 19p.MantleSubduction
DS200612-1449
2006
John-Awe, S.Upadhyay, D., John-Awe, S., Pin, C., Paquette, J.L., Braun, I.Neoproterozoic alkaline magmatism at Sivamalai, southern India.Gondwana Research, Vol. 10, 1-2, August pp. 156-166.IndiaAlkalic
DS201012-0701
2010
Johner, N.Shiryaev, A.A., Johner, N., Zedhenizov, D.A.Infra red mapping of defects in diamonds using a focal plane array ( FPA) detector.International Mineralogical Association meeting August Budapest, abstract p. 693.TechnologyDiamond inclusion - nitrogen
DS2003-0559
2003
Johnon, C.M.Hart, G.L., Johnon, C.M., Hildreth, W., Shirey, S.B.New osmium isotope evidence for intracrustal recycling of crustal domains with discreteGeology, Vol. 31, 5, pp. 427-30.mantleGeochronology
DS200412-0801
2003
Johnon, C.M.Hart, G.L., Johnon, C.M., Hildreth, W., Shirey, S.B.New osmium isotope evidence for intracrustal recycling of crustal domains with discrete ages.Geology, Vol. 31, 5, pp. 427-30.TechnologyMantle Geochronology
DS1996-0691
1996
Johns, M.K.Johns, M.K., Mosher, S.Physical models of regional fold superposition: the role of competencecontrastJournal of Structural Geology, Vol. 18, No. 4, Apr.1, pp. 375-492GlobalStructure, Folding
DS1975-0300
1976
Johns, R.K.Johns, R.K.Diamond- South AustraliaEconomic Geology AUSTRALIA AND PAPUA NEW GUINEA, No. 4, ED. KNIGH, No. 8, P. 309.Australia, South AustraliaEchunga, Algebuckina, County Kimberley, Diamond Occurrences
DS1991-0801
1991
Johns, R.K.Johns, R.K.Exploration in South Australia. Very brief mention of diamondsAustralian Institute of Mining and Metallurgy (AusIMM) Bulletin, No. 1, April p. 34AustraliaNews item, Diamond exploration activities
DS1995-1338
1995
Johnsen, K.Neumann, E.R., Wulff-Pedersen, E., Johnsen, K., AndersenPetrogenesis of spinel harzburgite and dunite suite xenoliths fromLanzarote, eastern Canary Islands.Lithos, Vol. 35, No. 1-2, April pp. 83-108.GlobalMantle, Xenoliths
DS1994-0848
1994
Johnsen, O.Johnsen, O., Nielsen, T.F.D., Ronsbo, J.G.Lamprophyllite and barytolam prophyllite from the Tertiary Gardiner East Greenland.Neues Jahr. Min., No. 7, July pp. 328-336.GreenlandLamprophyllite, Gardiner Complex
DS200412-1535
2004
Johnsen, O.Petersen, O.V., Johnsen, O., Gault, R.A., Niedermayr, G., Grice, J.D.Taseqite, a new member of the eudialyte group from the Ilmassaq alkaline complex.Neues Jahrbuch fur Mineralogie - Monatshefte, No. 2, Feb. 1, pp. 83-96.Europe, GreenlandMineralogy
DS201505-0254
2015
Johnsen, R.Ballmer, M.D., Conrad, C.P., Smith, E.I., Johnsen, R.Intraplate volcanism at the edges of the Colorado Plateau sustained by a combination of triggered edge-driven convection and shear-driven upwelling.Geochemistry, Geophysics, Geosystems: G3, Vol. 16, 2, pp. 366-379.United States, Colorado PlateauConvection

Abstract: Although volcanism in the southwestern United States has been studied extensively, its origin remains controversial. Various mechanisms such as mantle plumes, upwelling in response to slab sinking, and small-scale convective processes have been proposed, but have not been evaluated within the context of rapidly shearing asthenosphere that is thought to underlie this region. Using geodynamic models that include this shear, we here explore spatiotemporal patterns of mantle melting and volcanism near the Colorado Plateau. We show that the presence of viscosity heterogeneity within an environment of asthenospheric shearing can give rise to decompression melting along the margins of the Colorado Plateau. Our models indicate that eastward shear flow can advect pockets of anomalously low viscosity toward the edges of thickened lithosphere beneath the plateau, where they can induce decompression melting in two ways. First, the arrival of the pockets critically changes the effective viscosity near the plateau to trigger small-scale edge-driven convection. Second, they can excite shear-driven upwelling (SDU), in which horizontal shear flow becomes redirected upward as it is focused within the low-viscosity pocket. We find that a combination of “triggered” edge-driven convection and SDU can explain volcanism along the margins of the Colorado Plateau, its encroachment toward the plateau's southwestern edge, and the association of volcanism with slow seismic anomalies in the asthenosphere. Geographic patterns of intraplate volcanism in regions of vigorous asthenospheric shearing may thus directly mirror viscosity heterogeneity of the sublithospheric mantle.
DS1998-1093
1998
JohnsonOliver, G.J.H., Johnson, Williams, HerdRelict 1.4 Ga oceanic crust in the Zambezi Valley: evidence for Mesoproterozoic supercontinental fragmentGeology, Vol. 26, No. 6, June pp. 571-3.ZimbabweArchean craton, Zambezi belt
DS1999-0019
1999
JohnsonArden, K.M., DePaoli, Johnson, Hemstock, AbercrombieMetallic and industrial mineral assessment report on the Athabasca permitsin northeastern Alberta.Alberta Geological Survey, MIN 19990004AlbertaExploration - assessment, Birch Mountain Resources Ltd.
DS2000-0235
2000
JohnsonDilles, J.H., Barton, Johnson, Profet, EinaudiContrasting styles of intrusion associated hydrothermal systemsSociety of Economic Geologists Guidebook, Vol. 32, 160p.NevadaBook - table of contents, Deposit - Tin Creeks, Getchell, Pinson
DS2001-0970
2001
JohnsonReinitz, I.M., Johnson, Hemphill, Gilbertson et. al.Modeling the appearance of the round brilliant cut diamond: an analysis of fire and more about brilliance.Gems and Gemology, Vol. 37, Fall, pp. 174-97.GlobalDiamond - cutting, Brilliance
DS200812-0524
2007
Johnson, A.Johnson, A., Stachel, T., Creighton, S.,Naher, U.Peridotite xenoliths from the Monument Property, Slave Craton, NWT, Canada. SouthernEra35th. Yellowknife Geoscience Forum, Abstracts only p. 29.Canada, Northwest TerritoriesMineralogy
DS202010-1863
2020
Johnson, A.B.Murphy, K.P., Johnson, A.B.Sailing the sea of open access: celestial navigation or dead reckoning?Mineralogical Magazine, Vol. 84, pp. 495-501. pdfGlobalhistory

Abstract: The Open Access movement has gathered significant momentum over the last couple of years. This has been instigated largely by cOAlition S and those funders which support its aims. Is ‘Read and Publish’ the way forward? Will it work for all publishers? All authors? All subscribers? All readers? This article looks at the history of OA and updates a similar piece from 2013. A detailed glossary of terms is given at the end of the article.
DS1994-1702
1994
Johnson, A.C.Storey, B.C., Parkhurst, R.J., Johnson, A.C.The Grenville Province within Antarctica: a test of the SWEAT hypothesisJournal of the Geological Society of London, Vol. 151, pat. 1, January pp. 1-4AntarcticaMagmatism
DS202107-1120
2021
Johnson, A.C.Ostrander, C.M., Johnson, A.C., Anbar, A.D.Earth's first redox revolution.Annual Review of Earth and Planetary Sciences, Vol. 49, pp. 337-366.Mantleredox

Abstract: The rise of molecular oxygen (O2) in the atmosphere and oceans was one of the most consequential changes in Earth's history. While most research focuses on the Great Oxidation Event (GOE) near the start of the Proterozoic Eon—after which O2 became irreversibly greater than 0.1% of the atmosphere—many lines of evidence indicate a smaller oxygenation event before this time, at the end of the Archean Eon (2.5 billion years ago). Additional evidence of mild environmental oxidation—probably by O2—is found throughout the Archean. This emerging evidence suggests that the GOE might be best regarded as the climax of a broader First Redox Revolution (FRR) of the Earth system characterized by two or more earlier Archean Oxidation Events (AOEs). Understanding the timing and tempo of this revolution is key to unraveling the drivers of Earth's evolution as an inhabited world—and has implications for the search for life on worlds beyond our own. Many inorganic geochemical proxies suggest that biological O2 production preceded Earth's GOE by perhaps more than 1 billion years. Early O2 accumulation may have been dynamic, with at least two AOEs predating the GOE. If so, the GOE was the climax of an extended period of environmental redox instability. We should broaden our focus to examine and understand the entirety of Earth's FRR.
DS1991-1223
1991
Johnson, A.M.Neavel, K.E., Johnson, A.M.Entrainment in compositionally bouyant plumesTectonophysics, Vol. 200, pp. 1-15GlobalPlumes, Experimental petrology
DS201509-0404
2015
Johnson, B.Johnson, B., Goldblatt, C.The nitrogen budget of Earth.Earth Science Reviews, Vol. 148, pp. 150-173.MantleNitrogen

Abstract: We comprehensively compile and review N content in geologic materials to calculate a new N budget for Earth. Using analyses of rocks and minerals in conjunction with N–Ar geochemistry demonstrates that the Bulk Silicate Earth (BSE) contains ~ 7 ± 4 times present atmospheric N (4 × 1018 kg N, or PAN), with 27 ± 16 × 1018 kg N. Comparison to chondritic composition, after subtracting N sequestered into the core, yields a consistent result, with BSE N between 17 ± 13 × 1018 kg to 31 ± 24 × 1018 kg N. Embedded in the chondritic comparison we calculate a N mass in Earth's core (180 ± 110 to 30 ± 180 × 1018 kg) as well as present discussion of the Moon as a proxy for the early mantle. Significantly, our study indicates that the majority of the planetary budget of N is in the solid Earth. We suggest that the N estimate here precludes the need for a “missing N” reservoir. Nitrogen–Ar systematics in mantle rocks and primary melts identify the presence of two mantle reservoirs: MORB-source like (MSL) and high-N. High-N mantle is composed of young, N-rich material subducted from the surface and identified in OIB and some xenoliths. In contrast, MSL appears to be made of old material, though a component of subducted material is evident in this reservoir as well. Taking into account N mass and isotopic character of the atmosphere and BSE, we calculate a ?15N value of ~ 2%. This value should be used when discussing bulk Earth N isotope evolution. Additionally, our work indicates that all surface N could pass through the mantle over Earth history, and in fact the mantle may act as a long-term sink for N. Since N acts as a tracer of exchange between the atmosphere, oceans, and mantle over time, clarifying its distribution in the Earth is critical for evolutionary models concerned with Earth system evolution. We suggest that N be viewed in the same light as carbon: it has a fast, biologically mediated cycle which connects it to a slow, tectonically-controlled geologic cycle.
DS1985-0427
1985
Johnson, B.D.Mayhew, M.A., Johnson, B.D., Wasilews, P.J.A Review of Problems and Progress in Studies of Satellite Magnetic Anomalies.Journal of Geophysical Research, Vol. 90, No. 83, PP. 2511-2522.GlobalGeophysics, Remote Sensing
DS1986-0408
1986
Johnson, B.D.Johnson, B.D., Mayhewm M.A., O'Reilly, S.Y., Griffin, W.L., ArnottMagsat anomalies, crustal magnetisation, heat flow and kimberlite occurrences in AustraliaProceedings of the Fourth International Kimberlite Conference, Held Perth, Australia, Geological, No. 16, pp. 127-129AustraliaGeophysics, Magnetics
DS1986-0623
1986
Johnson, B.D.O'Reilly, S.Y., Griffin, W.L., Johnson, B.D.Petrological constraints on geophysical models for the lowercrust, mohoand mantle: thermal and seismic interpretationsProceedings of the Fourth International Kimberlite Conference, Held Perth, Australia, No. 16, pp. 303-305AustraliaGeophysics
DS1990-0767
1990
Johnson, B.J.Johnson, B.J.Stratigraphy and structure of the Early Proterozoic Wilson Island Group East Arm thrust fold belt, northwest Territories.Canadian Journal of Earth Sciences, Vol. 27, pp. 552-69.Northwest TerritoriesTectonics - structure
DS201711-2519
2017
Johnson, B.W.Johnson, B.W., Goldblatt, C.A secular increase in continental crust nitrogen during the Precambrian. Glacial tillsGeochemical Perspectives Letters, Vol. 4, pp. 24-28.Mantlegeomorphology

Abstract: Recent work indicates the presence of substantial geologic nitrogen reservoirs in the mantle and continental crust. Importantly, this geologic nitrogen has exchanged between the atmosphere and the solid Earth over time. Changes in atmospheric nitrogen (i.e. atmospheric mass) have direct effects on climate and biological productivity. It is difficult to constrain, however, the evolution of the major nitrogen reservoirs through time. Here we show a secular increase in continental crust nitrogen through Earth history recorded in glacial tills (2.9 Ga to modern), which act as a proxy for average upper continental crust composition. Archean and earliest Palaeoproterozoic tills contain 66 ± 100 ppm nitrogen, whereas Neoproterozoic and Phanerozoic tills contain 290 ± 165 ppm nitrogen, whilst the isotopic composition has remained constant at ~4‰. Nitrogen has accumulated in the continental crust through time, likely sequestered from the atmosphere via biological fixation. Our findings support dynamic, non-steady state behaviour of nitrogen through time, and are consistent with net transfer of atmospheric N to geologic reservoirs over time.
DS201810-2332
2018
Johnson, B.W.Johnson, B.W., Goldblatt, C.The new Earth system nitrogen model. EarthNGeochemistry, Geophysics, Geosystems, Vol. 19, 8, pp. 2516-2542.Mantlenitrogen

Abstract: The amount of nitrogen in the atmosphere, oceans, crust, and mantle have important ramifications for Earth's biologic and geologic history. Despite this importance, the history and cycling of nitrogen in the Earth system is poorly constrained over time. For example, various models and proxies contrastingly support atmospheric mass stasis, net outgassing, or net ingassing over time. In addition, the amount available to and processing of nitrogen by organisms is intricately linked with and provides feedbacks on oxygen and nutrient cycles. To investigate the Earth system nitrogen cycle over geologic history, we have constructed a new nitrogen cycle model: EarthN. This model is driven by mantle cooling, links biologic nitrogen cycling to phosphate and oxygen, and incorporates geologic and biologic fluxes. Model output is consistent with large (2-4x) changes in atmospheric mass over time, typically indicating atmospheric drawdown and nitrogen sequestration into the mantle and continental crust. Critical controls on nitrogen distribution include mantle cooling history, weathering, and the total Bulk Silicate Earth+atmosphere nitrogen budget. Linking the nitrogen cycle to phosphorous and oxygen levels, instead of carbon as has been previously done, provides new and more dynamic insight into the history of nitrogen on the planet.
DS202004-0520
2020
Johnson, B.W.Johnson, B.W., Wing, B.A.Limited Archean continental emergence reflected in an early Archean 180-enriched ocean.Nature Geoscience, 10.1038/s41561-020-0538-9Australiawater

Abstract: The origin and evolution of Earth’s biosphere were shaped by the physical and chemical histories of the oceans. Marine chemical sediments and altered oceanic crust preserve a geochemical record of these histories. Marine chemical sediments, for example, exhibit an increase in their 18O/16O ratio through time. The implications of this signal are ambiguous but are typically cast in terms of two endmember (but not mutually exclusive) scenarios. The oceans may have been much warmer in the deep past if they had an oxygen isotope composition similar to that of today. Alternatively, the nature of fluid-rock interactions (including the weathering processes associated with continental emergence) may have been different in the past, leading to an evolving oceanic oxygen isotope composition. Here we examine approximately 3.24-billion-year-old hydrothermally altered oceanic crust from the Panorama district in the Pilbara Craton of Western Australia as an alternative oxygen isotope archive to marine chemical sediments. We find that, at that time, seawater at Panorama had an oxygen isotope composition enriched in 18O relative to the modern ocean with a ?18O of 3.3?±?0.1‰ VSMOW. We suggest that seawater ?18O may have decreased through time, in contrast to the large increases seen in marine chemical sediments. To explain this possibility, we construct an oxygen isotope exchange model of the geologic water cycle, which suggests that the initiation of continental weathering in the late Archaean, between 3 and 2.5 billion years ago, would have drawn down an 18O-enriched early Archaean ocean to ?18O values similar to those of modern seawater. We conclude that Earth’s water cycle may have gone through two separate phases of steady-state behaviour, before and after the emergence of the continents.
DS202109-1472
2021
Johnson, B.W.Hoffman, P.F., Halverson, G.P., Schrag, D.P., Higgins, J.A., Domack, E.W., Macdonald, F.A., Pruss, S.B., Blattler, C.L., Crockford, P.W., Hodgin, E.B., Bellefroid, E.J., Johnson, B.W., Hodgskiss, M.S.W., Lamothe, K.G., LoBianco, S.J.C., Busch, J.F., HowesSnowballs in Africa: sectioning a long-lived Neoproterozoic carbonate platform and its bathyal foreslope ( NW Namibia). (Octavi Group)Earth Science Reviews , Vol. 219, 103616 231p. PdfAfrica, NamibiaCraton - Congo

Abstract: Otavi Group is a 1.5-3.5-km-thick epicontinental marine carbonate succession of Neoproterozoic age, exposed in an 800-km-long Ediacaran?Cambrian fold belt that rims the SW cape of Congo craton in northern Namibia. Along its southern margin, a contiguous distally tapered foreslope carbonate wedge of the same age is called Swakop Group. Swakop Group also occurs on the western cratonic margin, where a crustal-scale thrust cuts out the facies transition to the platformal Otavi Group. Subsidence accommodating Otavi Group resulted from S?N crustal stretching (770-655?Ma), followed by post-rift thermal subsidence (655-600?Ma). Rifting under southern Swakop Group continued until 650-635?Ma, culminating with breakup and a S-facing continental margin. No hint of a western margin is evident in Otavi Group, suggesting a transform margin to the west, kinematically consistent with S?N plate divergence. Rift-related peralkaline igneous activity in southern Swakop Group occurred around 760 and 746?Ma, with several rift-related igneous centres undated. By comparison, western Swakop Group is impoverished in rift-related igneous rocks. Despite low paleoelevation and paleolatitude, Otavi and Swakop groups are everywhere imprinted by early and late Cryogenian glaciations, enabling unequivocal stratigraphic division into five epochs (period divisions): (1) non-glacial late Tonian, 770-717?Ma; (2) glacial early Cryogenian/Sturtian, 717-661?Ma; (3) non-glacial middle Cryogenian, 661-646?±?5?Ma; (4) glacial late Cryogenian/Marinoan, 646?±?5-635?Ma; and (5) non-glacial early Ediacaran, 635-600?±?5?Ma. Odd numbered epochs lack evident glacioeustatic fluctuation; even numbered ones were the Sturtian and Marinoan snowball Earths. This study aimed to deconstruct the carbonate succession for insights on the nature of Cryogenian glaciations. It focuses on the well-exposed southwestern apex of the arcuate fold belt, incorporating 585?measured sections (totaling >190?km of strata) and?>?8764 pairs of ?13C/?18Ocarb analyses (tabulated in Supplementary On-line Information). Each glaciation began and ended abruptly, and each was followed by anomalously thick ‘catch-up’ depositional sequences that filled accommodation space created by synglacial tectonic subsidence accompanied by very low average rates of sediment accumulation. Net subsidence was 38% larger on average for the younger glaciation, despite its 3.5-9.3-times shorter duration. Average accumulation rates were subequal, 4.0 vs 3.3-8.8?m Myr?1, despite syn-rift tectonics and topography during Sturtian glaciation, versus passive-margin subsidence during Marinoan. Sturtian deposits everywhere overlie an erosional disconformity or unconformity, with depocenters ?1.6?km thick localized in subglacial rift basins, glacially carved bedrock troughs and moraine-like buildups. Sturtian deposits are dominated by massive diamictite, and the associated fine-grained laminated sediments appear to be local subglacial meltwater deposits, including a deep subglacial rift basin. No marine ice-grounding line is required in the 110 Sturtian measured sections in our survey. In contrast, the newly-opened southern foreslope was occupied by a Marinoan marine ice grounding zone, which became the dominant repository for glacial debris eroded from the upper foreslope and broad shallow troughs on the Otavi Group platform, which was glaciated but left nearly devoid of glacial deposits. On the distal foreslope, a distinct glacioeustatic falling-stand carbonate wedge is truncated upslope by a glacial disconformity that underlies the main lowstand grounding-zone wedge, which includes a proximal 0.60-km-high grounding-line moraine. Marinoan deposits are recessional overall, since all but the most distal overlie a glacial disconformity. The Marinoan glacial record is that of an early ice maximum and subsequent slow recession and aggradation, due to tectonic subsidence. Terminal deglaciation is recorded by a ferruginous drape of stratified diamictite, choked with ice-rafted debris, abruptly followed by a syndeglacial-postglacial cap-carbonate depositional sequence. Unlike its Sturtian counterpart, the post-Marinoan sequence has a well-developed basal transgressive (i.e., deepening-upward) cap dolomite (16.9?m regional average thickness, n?=?140) with idiosyncratic sedimentary features including sheet-crack marine cements, tubestone stromatolites and giant wave ripples. The overlying deeper-water calci-rhythmite includes crystal-fans of former aragonite benthic cement ?90?m thick, localized in areas of steep sea-floor topography. Marinoan sequence stratigraphy is laid out over ?0.6?km of paleobathymetric relief. Late Tonian shallow-neritic ?13Ccarb records were obtained from the 0.4-km-thick Devede Fm (~770-760?Ma) in Otavi Group and the 0.7-km-thick Ugab Subgroup (~737-717?Ma) in Swakop Group. Devede Fm is isotopically heavy, +4-8‰ VPDB, and could be correlative with Backlundtoppen Fm (NE Svalbard). Ugab Subgroup post-dates 746?Ma volcanics and shows two negative excursions bridged by heavy ?13C values. The negative excursions could be correlative with Russøya and Garvellach CIEs (carbon isotope excursions) in NE Laurentia. Middle Cryogenian neritic ?13C records from Otavi Group inner platform feature two heavy plateaus bracketed by three negative excursions, correlated with Twitya (NW Canada), Taishir (Mongolia) and Trezona (South Australia) CIEs. The same pattern is observed in carbonate turbidites in distal Swakop Group, with the sub-Marinoan falling-stand wedge hosting the Trezona CIE recovery. Proximal Swakop Group strata equivalent to Taishir CIE and its subsequent heavy plateau are shifted bidirectionally to uniform values of +3.0-3.5‰. Early Ediacaran neritic ?13C records from Otavi Group inner platform display a deep negative excursion associated with the post-Marinoan depositional sequence and heavy values (??+?11‰) with extreme point-to-point variability (?10‰) in the youngest Otavi Group formation. Distal Swakop Group mimics older parts of the early Ediacaran inner platform ?13C records, but after the post-Marinoan negative excursion, proximal Swakop Group values are shifted bidirectionally to +0.9?±?1.5‰. Destruction of positive and negative CIEs in proximal Swakop Group is tentatively attributed to early seawater-buffered diagenesis (dolomitization), driven by geothermal porewater convection that sucks seawater into the proximal foreslope of the platform. This hypothesis provocatively implies that CIEs originating in epi-platform waters and shed far downslope as turbidites are decoupled from open-ocean DIC (dissolved inorganic carbon), which is recorded by the altered proximal Swakop Group values closer to DIC of modern seawater. Carbonate sedimentation ended when the cratonic margins collided with and were overridden by the Atlantic coast-normal Northern Damara and coast-parallel Kaoko orogens at 0.60-0.58?Ga. A forebulge disconformity separates Otavi/Swakop Group from overlying foredeep clastics. In the cratonic cusp, where the orogens meet at a right angle, the forebulge disconformity has an astounding ?1.85?km of megakarstic relief, and km-thick mass slides were displaced gravitationally toward both trenches, prior to orogenic shortening responsible for the craton-rimming fold belt.
DS200612-0272
2005
Johnson, C.Constable, C., Johnson, C.A paleomagnetic power spectrum.Physics of the Earth and Planetary Interiors, Vol. 153, 1-3, pp. 61-73.MantleGeophysics - magnetics
DS200812-0091
2008
Johnson, C.Beard, B., Johnson, C., Bell, K.Iron isotope compositions of carbonatites record melt generation and late stage volatile loss processes.Goldschmidt Conference 2008, Abstract p.A62.MantleCarbonatite
DS200912-0339
2009
Johnson, C.Johnson, C., Stachel, T., Muehlenbachs, K., Armstrong, J.The micro-/macro diamond relationship: a preliminary case study on diamonds from Artemisia kimberlite ( northern Slave Craton), Canada.37th. Annual Yellowknife Geoscience Forum, Abstracts p. 74-75.Canada, Nunavut, Coronation Gulfmicrodiamonds
DS1982-0299
1982
Johnson, C.A.Johnson, C.A., Essene, E.J.The Formation of Garnet in Olivine-bearing Metagabbros From the Adirondacks.Contributions to Mineralogy and Petrology, Vol. 81, No. 3, PP. 240-247.United States, AppalachiaBlank
DS200612-0552
2006
Johnson, C.B.Hayes, G.P., Johnson, C.B., Furlong, K.P.Evidence for melt injection in the crust of northern California?Earth and Planetary Science Letters, Vol. 248, 3-4, Aug. 30, pp. 638-649.United States, CaliforniaMelting
DS1981-0224
1981
Johnson, C.J.Johnson, C.J.Minerals Objectives, Policies and Strategies in Botswana-analysis and Lessons.Nat. Res. Forum, Vol. 5, PP. 347-367.BotswanaKimberlite, Politics, Diamond Mining
DS1988-0331
1988
Johnson, C.J.Johnson, C.J., Clark, A.L.Mineral exploration in developing countries, Botswana and Papua New Guinea case studiesIn: World Mineral Exploration, trends economic issues, Publishing Resources for, pp. 145-178BotswanaHistory -diamonds
DS1992-0101
1992
Johnson, C.L.Beard, B.L., Johnson, C.L., Barovich, K.M.Hafnium isotopic composition of basaltic rocks from northwestern Colorado: evidence for changing source region mineralogy with timeEos, Transactions, Annual Fall Meeting Abstracts, Vol. 73, No. 43, October 27, abstracts p. 655ColoradoBasalts, Geochronology
DS2002-0783
2002
Johnson, C.L.Johnson, C.L., Buseck, P.R.Transmission electron microscopy of dislocation structures in olivine18th. International Mineralogical Association Sept. 1-6, Edinburgh, abstract p.78. (poster)MantleUHP mineralogy, Tectonic processes
DS201312-0442
2013
Johnson, C.L.Johnson, C.L., Ross, M., Grunsky, E., Hodder, T.J.Fingerprinting glacial processes for diamond exploration on Baffin Island.Geoscience Forum 40 NWT, Poster abstract only p. 62Canada, Nunavut, Baffin IslandGeomorphology
DS1989-1496
1989
Johnson, C.M.Thompson, R.A., Johnson, C.M.Early rift basaltic volcanism of the northern Rio Grande riftNew Mexico Bureau of Mines Bulletin., Continental Magmatism Abstract Volume, Held, Bulletin. No. 131, p. 268 Abstract held June 25-July 1New MexicoTectonics, Rift
DS1990-0768
1990
Johnson, C.M.Johnson, C.M.Comment on lower crustal evolution under central Arizona: Strontium, neodymium, and lead isotopic and geochemical evidence from the mafic xenoliths of Camp CreekEarth and Planetary Science Letters, Vol. 99, pp. 400-409ArizonaXenoliths, Camp Creek
DS1991-0087
1991
Johnson, C.M.Beard, B.L., Medaris, L.G.Jr., Johnson, C.M.Diverse origins and ages of eclogite and garnet peridotite from the Bohemian Massif, CzechoslovakiaGeological Society of America Annual Meeting Abstract Volume, Vol. 23, No. 5, San Diego, p. A 46GlobalEclogite, Peridotite
DS1993-0092
1993
Johnson, C.M.Beard, B.L., Johnson, C.M.Hafnium isotope composition of late Cenozoic basaltic rocks from northwestern Colorado, United States (US): new constraints on mantle enrichment processes.Earth and Planetary Science Letters, Vol. 119, No. 4, October pp. 495-510.ColoradoGeochronology, Mantle enrichment
DS1993-0752
1993
Johnson, C.M.Johnson, C.M.Mesozoic and Cenozoic contributions to crustal growth in the southwestern United StatesEarth and Planetary Science Letters, Vol. 118, pp. 75-89California, Nevada, Utah, Colorado, New Mexico, ArizonaCrust mantle boundary, Mass-age distributions, Geochronology
DS1993-0753
1993
Johnson, C.M.Johnson, C.M., Beard, B.L.Evidence from hafnium isotopes for ancient sub-oceanic mantle beneath the Rio Grande riftNature, Vol. 362, No. 6419, April 1, pp. 441-443Colorado Plateau, New Mexico, ArizonaTectonics, Rio Grande Rift, Geochronology
DS1997-1002
1997
Johnson, C.M.Scherer, E.E., Cameron, K.L., Johnson, C.M., Beard, B.Lutetium - Hafnium geochronology applied to dating Cenozoic events affecting lower crustal xenoliths Kilbourne Hole.Chemical Geol., Vol. 142, No. 1-2, Oct. 20, pp. 63-78.New MexicoGeochronology, Kilbourne Hole
DS1997-1198
1997
Johnson, C.M.Van Wyck, N., Johnson, C.M.Common lead Sm Sd and uranium-lead (U-Pb) constraints on petrogenesis, crustal architecture and tectonic setting of PenokeanGeological Society of America (GSA) Bulletin, Vol. 109, No. 7, pp. 799-808WisconsinPaleoproterozoic, geochronology, petrology, Penokean Orogeny
DS2003-0925
2003
Johnson, C.M.Medaris, L.G., Singer, B.S., Dott, R.H., Naymark, A., Johnson, C.M., SchottLate Paleoproterozoic climate, tectonics and metamorphism in the southern LakeJournal of Geology, Vol. 111, 3, pp. 243-258.MichiganTectonics
DS200412-1286
2003
Johnson, C.M.Medaris, L.G., Singer, B.S., Dott, R.H., Naymark, A., Johnson, C.M., Schott, R.C.Late Paleoproterozoic climate, tectonics and metamorphism in the southern Lake Superior region and proto North America: evidenceJournal of Geology, Vol. 111, 3, pp. 243-258.United States, MichiganTectonics
DS200612-0763
2005
Johnson, C.M.Lapen, T.J., Medaris, L.G., Johnson, C.M., Beard, B.L.Archean to middle Proterozoic evolution of Baltica subcontinental lithosphere:Contributions to Mineralogy and Petrology, Vol. 150, 2, pp. 131-145.Europe, Baltic ShieldTectonics
DS200812-0525
2008
Johnson, C.M.Johnson, C.M., Beard, B.L., Roden, E.E.The iron isotope fingerprints of redox and biogeochemical cycling in modern and ancient Earth.Annual Review of Earth and Planetary Sciences, Vol. 36, May, pp. 457-493.MantleRedox
DS200912-0340
2009
Johnson, C.M.Johnson, C.M., Bell, K., Beard, B.L., Shultis, A.J.Iron isotope compositions of carbonatites record melt generation, crystallization and late stage volatile transport processes.Mineralogy and Petrology, in press availableGlobalCarbonatite, geochronology
DS200912-0421
2009
Johnson, C.M.Kylander Clar, A.R.C., Hacker, B.R., Johnson, C.M., Beard, B.L., Mahlen, N.Slow subduction of a thick ultrahigh pressure terrane.Tectonics, Vol. 28, 2, TC2003MantleUHP
DS201012-0327
2010
Johnson, C.M.Johnson, C.M., Bell, K., Benard, B.L.,Shultis, A.L.Iron isotope compositions of carbonatites record melt generation, crystallization and late stage volatile transport systems.Mineralogy and Petrology, Vol. 98, 1-4, pp. 91-110.MantleCarbonatite
DS201012-0328
2010
Johnson, C.N.Johnson, C.N., Stern, R., Stachel, T., Muehlenbachs, K., Armstrong, J.The micro/macro diamond relationship: a case study from the Artemisia kimberlite northern Slave Craton ( Nunavut, Canada).38th. Geoscience Forum Northwest Territories, Abstract p. 52.Canada, NunavutDeposit - Artemisia
DS201212-0340
2012
Johnson, C.N.Johnson, C.N., Stachel, T., Muehlenbachs, K., Stern, R.A., Armstrong, J.P., EIMFThe micro/macro diamond relationship: a case study from the Artemisia kimberlite ( northern Slave Craton), Canada.Lithos, Vol. 148, pp. 86-97.Canada, Northwest TerritoriesDeposit - Artemisia
DS201511-1846
2012
Johnson, C.N.Johnson, C.N., Stachel, T., Muehlenbachs, K., Stern, R.A., Armstrong, J.P.The micro/macro diamond relationship: a case study from the Artemisia kimberlite ( Northern Slave Craton) Canada.Lithos, Vol. 148, pp. 86-97. Available pdfCanada, Northwest TerritoriesMicrodiamonds - responses

Abstract: Size frequency distributions are the principal tool for predicting the macro-diamond grade of new kimberlite discoveries, based on micro-diamonds (i.e., diamond ? 0.5 mm) recovered from small exploration samples. Lognormal size frequency distributions – as observed for the Artemisia kimberlite (Slave Craton, Canada) – suggest a common source for micro- and macro-diamonds recovered from single samples, an implication that has never been conclusively tested. We analyzed 209 diamonds between 0.2 and 2 mm in size from the Artemisia kimberlite for their carbon isotopic compositions and nitrogen characteristics to determine the nature of the micro-/macro-diamond relationship.-Despite overall similarity in the ?13C distributions of micro- and macro-diamonds – both are bimodal with peaks in classes ? 5.0 to ? 4.5‰ and ? 3.5 to ? 3.0‰ – rare diamonds with ?13C between ? 14.2 and ? 24.5‰ of presumed eclogitic origin are restricted to macro-diamonds, whereas positive values are only observed for micro-diamonds. In addition, a shift in main mode and median value in ?13C of about +1‰ is observed for micro- relative to macro-diamonds. Fundamental differences between micro- and macro-diamonds at Artemisia were revealed through the analysis of nitrogen concentrations: 68% of micro-diamonds are Type II (“nitrogen free”) versus 21% of macro-diamonds, and only 19% of micro-diamonds have nitrogen contents > 100 atomic ppm versus 43% of macro-diamonds. Similarly, the presence of a detectable hydrogen related peak (at 3107 cm? 1) increases from 40% for micro-diamonds to 94% for macro-diamonds.-Previous studies on diamond populations from individual deposits have documented that single batches of ascending kimberlite or lamproite magma sample multiple diamond subpopulations formed during distinct growth events in compositionally variable sources and at various depth levels. The Artemisia data clearly show that even over a fairly narrow size interval, spanning the micro- to macro-diamond transition, the specific diamond subpopulations present and their relative proportions may vary significantly with diamond size. At Artemisia, we conclude that the observed lognormal size distribution is not a reflection of an entirely common origin of micro- and macro-diamonds.
DS1998-0700
1998
Johnson, D.Johnson, D.Sea bed mining off Africa's diamond coast - Diamond Field's Luderitzproject.29th. Annual Underwater Mining Institute, 1p. abstractSouth Africa, NamibiaMarine mining
DS1991-1209
1991
Johnson, D.C.Mutschler, F.E., Johnson, D.C., Mooney, T.C.A speculative plate kinematic model for the central Montana alkalic province and related gold depositsGuidebook of the Central Montana Alkalic Province, ed. Baker, D.W., Berg. R., No. 100, pp. 121-123. extended abstractMontanaAlkaline rocks, Gold emphasis
DS1991-1210
1991
Johnson, D.C.Mutschler, F.E., Mooney, T.C., Johnson, D.C.Precious metal deposits related to alkaline igneous rocks - a space timetrip through the CordilleraMining Engineering, Vol. 43, No. 3, March pp. 304-309CordilleraKimberlites, Alkaline rocks
DS1995-1318
1995
Johnson, D.C.Mutschler, F.E., Johnson, D.C., Mooney, T.C.A selected bibliography of alkaline igneous rocks and related mineraldeposits, with emphasis on N. America.United States Geological Survey (USGS) Open File, No. 94-0624A, 222p. $ 35.00CordilleraAlkaline rocks, Bibliography -metallogeny -not specific to diamonds
DS2000-0449
2000
Johnson, D.D.Johnson, D.D.Diamond Fields International - overview of company and activitiesWorld Diamond Conference Toronto June 19-20, 12p. slidesNamibiaNews item, Diamond Fields International - promotional literature
DS1990-0769
1990
Johnson, D.S.Johnson, D.S.Mining partners in the 90's: friend or foe?Northwest Mining Association Preprint, 3pUnited StatesLegal, Partnership parameters
DS1989-0715
1989
Johnson, E.Johnson, E., Wood, B.J.Oxidation states and rare earth elements (REE) contents of spinel lherzolite xenoliths:implications for metasomatic processes in the upper mantleEos, Vol. 70, No. 15, April 11, p. 510. (Abstract)United States, Japan, Australia, FranceXenoliths, Lherzolite
DS201112-1002
2011
Johnson, E.A.Stempniewicz, V.A., Johnson, E.A.The Archean of North America: the core of a continent.Geological Society of America, Annual Meeting, Minneapolis, Oct. 9-12, abstractUnited States, VirginiaMantle - water content
DS1987-0080
1987
Johnson, E.L.Bruha, D.J., Johnson, E.L.The extraterrestrial origin of kimberlites and their role in stopping lithospheric subductionTectonika Anathemata, Vol. 4, No. 4, 2pGlobalKimberlite, Genesis
DS1989-0716
1989
Johnson, E.L.Johnson, E.L., Swapp, S.M.The geochemistry and structural significance of a set of Middle Precambrian diabase dikes from the Highland Range, southwestern Montana.Canadian Journal of Earth Sciences, Vol. 26, pp. 119-28.MontanaGeochemistry - dikes
DS202102-0233
2021
Johnson, E.R.White, M.A., Kahwaji, S., Freitas, V.L.S., Siewert, R., Weatherby, J.A., Ribeiro da Silva, M.D.M.C., Verevkin, S.P., Johnson, E.R., Zwanziger, J.W.The relative thermodynamic stability of diamond and graphite.Angewandte Chemie International, Vol. 60, 3, pp. 1546-1549. pdfGlobaldiamond, graphite

Abstract: Recent density?functional theory (DFT) calculations raised the possibility that diamond could be degenerate with graphite at very low temperatures. Through high?accuracy calorimetric experiments closing gaps in available data, we reinvestigate the relative thermodynamic stability of diamond and graphite. For T<400 K, graphite is always more stable than diamond at ambient pressure. At low temperatures, the stability is enthalpically driven, and entropy terms add to the stability at higher temperatures. We also carried out DFT calculations: B86bPBE?25X?XDM//B86bPBE?XDM and PBE0?XDM//PBE?XDM results overlap with the experimental ?T?S results and bracket the experimental values of ?H and ?G, displaced by only about 2× the experimental uncertainty. Revised values of the standard thermodynamic functions for diamond are ?fHo=?2150±150 J?mol?1, ?fSo=3.44±0.03 J?K?1?mol?1 and ?fGo=?3170±150 J?mol?1.
DS201912-2784
2019
Johnson, G.Gilfillan, S.M.V., Gyore, D., Flude, S., Johnson, G., Bond, C.E., Hicks, N., Lister, R., Jones, D.G., Kremer, Y., Hazeldine, R.S., Stuart, F.M.Noble gases confirm plume related mantle degassing beneath southern Africa.Nature Communications, Vol. 10, 1, 10.1038/s41467-019-1244-6Africa, South Africaplumes

Abstract: Southern Africa is characterised by unusually elevated topography and abnormal heat flow. This can be explained by thermal perturbation of the mantle, but the origin of this is unclear. Geophysics has not detected a thermal anomaly in the upper mantle and there is no geochemical evidence of an asthenosphere mantle contribution to the Cenozoic volcanic record of the region. Here we show that natural CO2 seeps along the Ntlakwe-Bongwan fault within KwaZulu-Natal, South Africa, have C-He isotope systematics that support an origin from degassing mantle melts. Neon isotopes indicate that the melts originate from a deep mantle source that is similar to the mantle plume beneath Réunion, rather than the convecting upper mantle or sub-continental lithosphere. This confirms the existence of the Quathlamba mantle plume and importantly provides the first evidence in support of upwelling deep mantle beneath Southern Africa, helping to explain the regions elevation and abnormal heat flow.
DS1983-0491
1983
Johnson, G.R.O'leary, D.W., Johnson, G.R., England, A.W.Fracture Detection by Airborne Microwave Radiometry in Parts of the Mississippi Embayment, Missouri and Tennessee.Remote Sensing of The Environment., Vol. 13, No. 6, DECEMBER PP. 509-524.GlobalMid-continent
DS1994-0265
1994
Johnson, H.P.Carlson, R.L., Johnson, H.P.On modelling the thermal evolution of the oceanic upper mantle: anassessment of the cooling plate model.Journal of Geophysical Research, Vol. 99, . No. B 2, February 10, pp. 3201-3214.MantleModel -thermal
DS1994-0266
1994
Johnson, H.P.Carlson, R.L., Johnson, H.P.On modelling the thermal evolution of the oceanic upper mantle: as assessment of the cooling plate modelJournal of Geophysical Research, Vol. 99, No. B 2, February 10, pp. 3201-3214MantleTomography, Thermal evolution
DS1990-0770
1990
Johnson, I.Johnson, I.Success and geology. Presedential address to the Geol. Society ofAustraliaAustralian Geologist, Newsletter No. 74, March 30, pp. 6-9AustraliaEconomics, Exploration
DS1988-0268
1988
Johnson, J.D.Greiner, N.R., Phillips, D.S., Johnson, J.D., Volk, F.Diamonds in detonation sootNature, Vol. 333, No. 6172, June 2, pp. 440-441GlobalBlank
DS1900-0414
1906
Johnson, J.P.Johnson, J.P.The Geology of the Neighbourhood of the Roberts Victor Diamond Mine.Geological Society of South Africa Transactions, Vol. 9, PP. 117-124.Africa, South AfricaRegional Geology
DS1900-0415
1906
Johnson, J.P.Johnson, J.P., Young, R.B.The Relation of the Ancient Deposits of the Vaal River to The Palaeolithic Period of South Africa.Geological Society of South Africa Transactions, Vol. 9, PP. 53-56.Africa, South AfricaArchaeology, Geomorphology
DS1900-0464
1906
Johnson, J.P.Young, R.B., Johnson, J.P.Glacial Phenomena in Griqualand WestGeological Society of South Africa Transactions, Vol. 9, PP. 34-39.Africa, South AfricaGeomorphology
DS1900-0561
1907
Johnson, J.P.Johnson, J.P.Discussion on the Paper by Voit Entitled Kimberlite Dykes and Pipes. #4Geological Society of South Africa Proceedings, Vol. 10, P. ALSO: SOUTH AFRICA MAGAZINE, Vol. 75, SEPT. 14THAfrica, South AfricaPetrology, Kimberlite Mines And Deposits
DS1900-0562
1907
Johnson, J.P.Johnson, J.P.On the Geology of the Neighbourhood of the Roberts Victor Diamond Mine.Geological Society of South Africa Transactions, Vol. 9, PP. 117-124.Africa, South AfricaRegional Geology, Boshof Area, Petrography
DS1900-0563
1907
Johnson, J.P.Johnson, J.P.Note on the Lherzolite and Eclogite Boulders from the Roberts Victor Mine.Geological Society of South Africa Transactions, Vol. 10, PP. 112-114. ALSO: The Mining Journal, Vol. 82, SEPT. 28TAfrica, South AfricaUltrabasic Xenoliths, Mineralogy
DS1900-0673
1908
Johnson, J.P.Johnson, J.P.The Geology of the Roberts Victor Diamond MineJohannesburg: Priv. Publishing, London: J.s. Phillips, And London, 13P.Africa, South AfricaKimberlite Mines And Deposits
DS1900-0674
1908
Johnson, J.P.Johnson, J.P.The Eruptive Bearing Breccia of the Boshof District South Africa.Institute of Mining and Metallurgy. Transactions, Vol. 17, PP. 277-283.Africa, South AfricaPetrology, Mineralogy, Kimberlite Mines And Deposits
DS1900-0766
1909
Johnson, J.P.Johnson, J.P.Discussion of Paper by Harger Entitled the Occurrence of Diamonds in the Dwyka Conglomerate and Amygdaloidal Lavas.Geological Society of South Africa Proceedings, Vol. 12, PP. LVII-LVIII.Africa, South AfricaDiamond Genesis
DS1910-0061
1910
Johnson, J.P.Johnson, J.P.Geological and Archeological Notes on OrangiaLondon: Longmans And Co., 102P.South AfricaDiamonds, Mining, Kimberley
DS1910-0062
1910
Johnson, J.P.Johnson, J.P.Kimberlite Dykes and Pipes #2In: Geological And Archaeological Notes On Orangia., CHAPTER 3, PP. 17-43.South AfricaGenesis, Origin, Theory, History, Roberts Victor, Petrography
DS1910-0194
1911
Johnson, J.P.Johnson, J.P.The Mineral Industry of RhodesiaLondon:, 90P.ZimbabweDiamonds, Kimberley
DS1993-1249
1993
Johnson, J.R.Pollack, H.N., Hurter, S.J., Johnson, J.R.Heat flow from the earth's interior: analysis of the global dat a setReviews of Geophysics, Vol. 31, No. 3, August pp. 267-280.MantleGeophsyics, Lithosphere
DS1993-1250
1993
Johnson, J.R.Pollack, H.N., Hurterm S.J., Johnson, J.R.Heat flow from the earth's interior: analysis of the global dat a setReviews of Geophysics, Vol. 31, No. 3, August pp. 267-280GlobalGeophysics, Mantle, Heat Flow
DS1992-1399
1992
Johnson, J.S.Shurr, G.W., Johnson, J.S., Watkins, I.W.Surface expression of Precambrian tectonic features in Minnesota and surrounding statesGeological Society of America (GSA) Abstract Volume, Vol. 24, No. 4, April p. 64. abstract onlyMinnesotaTectonics, Geochemistry, geophysics
DS200512-0480
2005
Johnson, J.S.Johnson, J.S., Gibson, S.A., Thompson, R.N., Nowell, G.M.Volcanism in the Vitim volcanic field, Siberia: geochemical evidence for a mantle plume beneath the Baikal Rift zone.Journal of Petrology, Vol. 46, 7, July pp. 1309-1344.Russia, SiberiaGeochemistry - Vitim
DS200512-0481
2005
Johnson, J.S.Johnson, J.S., Gibson, S.A., Thompson, R.N., NOwell, G.M.Volcanism in the Vitim volcanic field, Siberia: geochemical evidence for a mantle plume beneath the Baikal Rift Zone.Journal of Petrology, Vol. 46, pp. 1309-1344.Russia, SiberiaPlume
DS1991-0802
1991
Johnson, J.W.Johnson, J.W., Norton, D.Critical phenomena in hydrothermal systems: state, thermodynamic, electrostatic, and transport properties of H2O in the critical regionAmerican Journal of Science, Vol. 291, June pp. 541-618GlobalHydrothermal systems, Fluid dynamics -water
DS1950-0281
1956
Johnson, K.Johnson, K.Arkansaw Diamond Mine. #2Commercial Appeal, Feb. 26TH. SECT. 5, P. 1.United States, Gulf Coast, Arkansas, PennsylvaniaNews Item
DS1992-0795
1992
Johnson, K.Johnson, K.Diamonds in them thar hills?Loveland Daily-Reporter Herald, Wed. May 20th. 1pColoradoNews item, Kelsey Lake
DS201412-0430
2014
Johnson, K.Johnson, K.Diamonds in Brazil: finally showing their potential.PDAC 2014, March 3, 1p. AbstractSouth America, BrazilDeposit - Brauna
DS201412-0431
2014
Johnson, K.Johnson, K.Diamonds in Brazil: finally showing their potential.6 Simposio Brasileiro de Geologia do Diamante, Aug. 3-7, 1p. AbstractSouth America, BrazilDeposit - Brauna
DS201812-2824
2018
Johnson, K.Johnson, K.Brauna: South America's first kimberlite diamond producer. Symposio Brasileiro de geologie do diamante , 23 ppts. Available pdfSouth America, Brazil, Bahiadeposit - Brauna
DS201812-2825
2018
Johnson, K.Johnson, K.Brauna diamond mine - South America's first kimberlite diamond producer. Lipari7th Symposio Brasileiro de Geologia do Diamante , Presentation listed South America, Brazil, Bahiadeposit - Brauna
DS202105-0769
2021
Johnson, K.Johnson, K., Donatti-Filho, J.P.Brauna 3 mine - South America's first diamond mine developed on a kimberlite deposit.Vancouver Kimberlite Cluster recorded, https://diamonds.eoas. ubc.ca/vancouver kimberliteclusterSouth America, Brazildeposit - Brauna

Abstract: Brazil hosts 1365 kimberlite or kimberlite-like bodies, as well as alluvial diamond deposits that have historically produced the bulk of Brazil's diamond production. Only five kimberlites have been subjected to bulk sampling evaluation using current exploration techniques and diamond recovery technology. The first of these kimberlite deposits to reach commercial production was the Brauna 3 kimberlite, with U-Pb age of 642±6 Ma elocated in the State of Bahia and owned and operated by Lipari Mineracao Ltds. The brauna mine commenced commercial production in 2016 at a capital cost of US $ 65 million, and to date has produced approximately 830,000 cts at an average recovered diamond grade of 21 cpht. The Brauna cluster features two pipe-like bodies, Brauna 3 and Brauna 7, and 22 kimberlite dyke occurrences located on the NE part of the Sao Francisco craton. A robust geological model delineates the Brauna 3 kimberlite pipe to depths of 550 and 410 m below surface for the South and Central-North Lobes, respectively. The geological model reveals a issregularly shapes kimberlite pipe which is structurally controlled by the NW trending strutural lineaments. petrographuic study of the Brauna 3 kimberlite has identified volcaniclastic and coherent kimberlites coexisting in a complex root to diatreme transition zone. The kimberlite is mineralogically close to Group 2 kimberlite containing olivine, spinel, ilmenite, phlogopite, perovskite, apatite, melilite, serpentine, carbonate and sulfates. Geochemically, the Brauna 3 kimberlite is transitional between Group 1 and Group 2 rocks.
DS1989-0717
1989
Johnson, K.E.Johnson, K.E., Wood, B.J.Closed system oxygen isotope behaviour in spinel lherzolite xenoliths:possible relations to oxidationstateEos, Vol. 70, No. 43, October 24, p. 1411. (Abstract)United States, Australia, Japan, Germany, FranceGeochronology, Xenoliths
DS1990-0771
1990
Johnson, K.E.Johnson, K.E., Davis, A.M., Bryndzia, L.T.Trace element variations in coexisting clinopyroxene and amphibole:implications for mantle MetasomatismGeological Society of America (GSA) Annual Meeting, Abstracts, Vol. 22, No. 7, p. A256CaliforniaDish Hill, Mantle Metasomatism
DS1990-1577
1990
Johnson, K.E.Wood, B.J., Bryndzia, L.T., Johnson, K.E.Mantle oxidation state and its relationship to tectonic environment and fluid speciationScience, Vol. 248, No. 4953, April 20, pp. 337-345GlobalTectonics, Mantle genesis
DS1992-0796
1992
Johnson, K.E.Johnson, K.E.Complementary HFSE-ULE variations in clinopyroxene, orthopyroxene, olivine and garnet from peridotite xenoliths: an appraisal enriched mantlecompositionsGeological Society of America (GSA) Abstracts with programs, 1992 Annual, Vol. 24, No. 7, abstract p. A259MantleMineral chemistry, Clinopyroxene
DS1993-0754
1993
Johnson, K.E.Johnson, K.E.Significance of reduced oxidation states for lherzolite xenoliths associated with plume volcanism: implications for MetasomatismGeological Society of America Annual Abstract Volume, Vol. 25, No. 6, p. A98 abstract onlyHawaiiLherzolite xenoliths
DS1996-0692
1996
Johnson, K.E.Johnson, K.E., Davis, A.M., Bryndzia, L.T.Contrasting styles of hydrous metasomatism in the upper mantle: an ion microprobe investigation.Geochimica et Cosmochimica Acta, Vol. 60, No. 8, April pp. 1367-85.MantleXenoliths, Metasomatism
DS1990-0772
1990
Johnson, K.I.M.Johnson, K.I.M., Dick, H.J.B., Shimizu, N.Melting in the oceanic upper mantle - an ion microprobe study of diopsides in abyssal peridotites (review)Journal of Geophysical Research, Vol. 95, No. 3, March 10, pp. 2661-2678GlobalMantle, Peridotites, microprobe
DS201601-0023
2015
Johnson, K.N.Johnson, K.N., Finnegan, N.J.A lithologic control on active meandering in bedrock channels.Geological Society of America Bulletin, Vol. 127, pp. 11/12, pp. 1766-1776.United States, CaliforniaNot specific to diamonds but of interest

Abstract: Topographic evidence requires that some rivers actively meander in bedrock, yet the way in which rivers can erode laterally and meander within bedrock banks is not well understood. Lateral channel migration, and especially lateral channel migration via active bedrock meandering, is commonly responsible for the preservation of unpaired strath terraces. A process-level understanding of lateral channel migration and active meandering in bedrock rivers is key to interpreting the climatic and tectonic significance of unpaired strath terraces and the planform shape of bedrock rivers. In this study, we compare erosional processes in two adjacent bedrock channels in the Santa Cruz Mountains, California. The main differences between these channels are that Pescadero Creek actively meanders within mudstone, while Butano Creek is straight and incises sandstone. Laboratory rock strength and slake durability tests show that while the two lithologies have similar tensile strengths before drying, the meander-supporting mudstone loses strength dramatically when dried and rewet (slakes), while the sandstone does not. The slaked mudstone bank rock was easily detached without the need for bed-load tools during in situ erosion tests, while mudstone that had not dried and sandstone were not detachable. The depth of bank rock detached solely from rewetting of previously dried mudstone ranges between 1 and 8 mm, which is well in excess of annual background erosion in the Santa Cruz Mountains. In addition, boulders of the mudstone rapidly disintegrated upon wetting and drying in the laboratory, whereas sandstone boulders remained intact. In the meandering stream, there is a consistent pattern of scoured bedrock (exposed to drying and slaking) along the outside "cutbank" of meander bends and forced bars that grade into soil and vegetation, which protect the bedrock from slaking along the inside of bends. Additionally, in the meandering stream, subaerially exposed mudstone clasts are often found to be disintegrating on the surface of bars. Taken together, these observations suggest that slaking allows for bedrock meandering in two fundamental ways. First, by rapidly disintegrating coarse hillslope-derived sediment that is deposited in the channel, slaking suppresses the negative feedback on lateral channel migration that would otherwise result from the buildup of talus along a retreating bedrock valley wall on the outside of a meander bend. Second, at cutbanks where scour exposes bare bedrock to drying, slaking weakens a layer of bank rock to the point where it can be eroded by clear-water flows. In these ways, slaking enables erosion into bedrock banks in response to curvature-driven fluid shear stress perturbations, as in alluvial rivers.
DS1989-0718
1989
Johnson, K.S.Johnson, K.S.Late Cambrian-Ordovician geology of the southern midcontinentOklahoma Geological Commission, scheduled symposium October 18-19 1989, MidcontinentGeology
DS1991-0803
1991
Johnson, K.S.Johnson, K.S.Late Cambrian-Ordovician geology of the southern Midcontinent, 1989symposiuM.Oklahoma Geological Survey, Circular 92, 227p. (Ontario Geological Survey (OGS) Library S 10198MidcontinentRegional geology, Cambrian-Ordovician conference
DS1992-0797
1992
Johnson, K.T.Johnson, K.T., Kusihiro, I.Segregation of high pressure partial melts from peridotite using aggregates of diamond: a new experimental approachGeophysical Research. Letters, Vol. 19, No. 16, August 21, pp. 1703-1706GlobalExperimental petrology, Diamond aggregates
DS1989-0719
1989
Johnson, K.T.M.Johnson, K.T.M., Dick, H.J.B., Shimizu, N.Trace elements in diopsides from oceanic peridotitesGeological Society of America (GSA) Annual Meeting Abstracts, Vol. 21, No. 6, p. A361. AbstractGlobalLherzolite, Petrology
DS1990-0814
1990
Johnson, K.T.M.Kelemen, P.B., Johnson, K.T.M., Kinzler, R.J., Irving, A.J.High field strength element depletions in arc basalts due to mantle magmainteractionNature, Vol. 345, June 7, pp. 521-524GlobalMantle, Basalts
DS1995-0887
1995
Johnson, K.W.Johnson, K.W.The revival of diamond production in the Central African Republic -from artisanal to industrial mining.Prospectors and Developers Association of Canada (PDAC) Annual Meeting, p. 52. abstractCentral African RepublicDiamond production, review, Mining, United Reef Limited
DS1996-0693
1996
Johnson, K.W.Johnson, K.W., Durocher, C.A.Trends technologies, and case histories for the modern explorationistProspectors and Developers Association of Canada (PDAC) Short Course, 250p. approx. $ 45.00GlobalBook -table of contents, Short course -Exploration technology
DS200512-0482
2005
Johnson, K.W.Johnson, K.W.Diamond exploration in South America: emerging from the shadows.PDAC 2005, Abstract 1p.South America, Brazil, Venezuela, Guyana, French GuianaBrief overview abstract
DS1989-0986
1989
Johnson, L.F.McGuffie, B.A., Johnson, L.F., Alley, R.E., Lang, H.R.IGIS Computer aided photogeologic mapping with image processing, graphic sand CAD/CAM capabilitiesGeobyte, Vol. 4, No. 5, pp. 8, 10-14. Database #18194GlobalComputer, Program -IGIS
DS1995-0888
1995
Johnson, L.H.Johnson, L.H., Jones, A.P.Ultramafic xenoliths and megacrysts from Deeti tuff cone, northernTanzania.Geological Society Africa 10th. Conference Oct. Nairobi, p. 123-4. Abstract.TanzaniaCarbonatite, Deposit -Deeti
DS1997-0561
1997
Johnson, L.H.Johnson, L.H., Jones, A.P., Church, A.A., Taylor, W.R.Ultramafic xenoliths and megacrysts from a melilitite tuff cone, Deeti, northern Tanzania.Journal of African Earth Sciences, Vol. 25, No. 1, July pp. 29-42.TanzaniaMelilitite, Xenoliths
DS1998-0187
1998
Johnson, L.H.Burgess, R., Johnson, L.H., Mattey, D., Harris, TurnerHelium, Argon, and Carbon isotopes in coated and polycrystalline diamonds.Chemical Geology, Vol. 146, No. 3-4, May 5, pp. 205-218.AustraliaGeochronology, Diamond morphology
DS1998-0701
1998
Johnson, L.H.Johnson, L.H., Burgess, R., Turner, MilledgeNoble gas and halogen systematics of fluids with diamond coats from Canada and Africa.7th International Kimberlite Conference Abstract, pp. 383-5.Northwest Territories, Botswana, ZaireDiamond inclusions, Diamond morphology - coated stones
DS1998-0702
1998
Johnson, L.H.Johnson, L.H., Burgess, R., Turner, MilledgeFluids trapped within diamond: clues to mantle geochemistry7th International Kimberlite Conference Abstract, pp. 380-2.South AfricaDiamond inclusions, Deposit - Venetia, Premier
DS2003-0662
2003
Johnson, L.H.Johnson, L.H., Phillips, D.40 Ar 40 Ar dating of mantle metasomatism: a noble approach or all hot air?8ikc, Www.venuewest.com/8ikc/program.htm, Session 4, POSTER abstractSouth AfricaMantle geochemistry, Deposit - Kimberley, geochronology
DS1975-0301
1976
Johnson, M.Johnson, M., Baker, D.R.Intrusive Model of the Magnet Cove Complex, ArkansawGeological Society of America (GSA), Vol. 8, No. 1, P. 26. (abstract.).United States, Gulf Coast, Arkansas, Hot Spring CountyGenesis, Structure
DS200712-1035
2006
Johnson, M.Stea, R., Hanchar, D., Johnson, M.Glacial mapping as an aid to diamond exploration.34th Yellowknife Geoscience Forum, p. 104. abstractCanada, NunavutTahera - till sampling
DS200812-0458
2008
Johnson, M.Hayman, P.C., Cas, R.F., Johnson, M.Difficulties in distinguishing coherent from fragmental kimberlite: a case study of the Muskox pipe ( northern Slave Province, Nunavut, Canada).Journal of Volcanology and Geothermal Research, Vol. 174, 1-3, pp. 139-151.Canada, NunavutCoherent hypabyssal, gradational contact, alteration
DS200912-0289
2009
Johnson, M.Hayman, P.C., Cas, R.A.F., Johnson, M.Characteristics and alteration origins of matrix minerals in volcaniclastic kimberlite of the Muskox pipe, Nunavut Canada.Lithos, In press - available 48p.Canada, NunavutDeposit - Muskox
DS201012-0754
2009
Johnson, M.Stea, R.R., Johnson, M., Hanchar, D.The geometry of kimberlite indicator mineral dispersal fans in Nunavut, Canada.Geological Association of Canada Short Course, No. 18, pp. 1-14.Canada, NunavutGeomorphology, geochemistry
DS201412-0432
2014
Johnson, M.Johnson, M.Application of geostatistics - overview in kimberlite evaluation.SRK and Friends Diamond Short Course, March 1, ppt p. 94-114.TechnologyGeostatistics - variography
DS201503-0151
2015
Johnson, M.Jakubec, J., Johnson, M.The Jericho diamond mine - what happened?Vancouver Kimberlite Cluster, Feb. 20, 1p. AbstractCanada, NunavutDeposit - Jericho
DS1975-0114
1975
Johnson, M.L.Johnson, M.L.Carbon and Oxygen Isotope Evolution in the Magnet Cove Complex, Arkansaw.Msc. Thesis, Rice University, Houston, Texas, 63P.United States, Gulf Coast, Arkansas, Hot Spring CountyBlank
DS1989-0834
1989
Johnson, M.L.Kuehner, S.M., Laughlin, J.R., Grossman, L., Johnson, M.L., BurnettDetermination of trace element mineral/liquid partition coefficients in melilite and diopside by ion and electron microprobe techniquesGeochimica et Cosmochimica Acta, Vol. 53, pp. 3115-3130GlobalMelilite, Experimental petrology
DS1994-0869
1994
Johnson, M.L.Kammerling, R.C., McClure, S.F., Johnson, M.L., et al.An update on filled diamonds: identification and durabilityGems and Gemology, Vol. 30, Fall pp. 142-177.GlobalDiamond -fracture filled, Diamond markets, industry
DS1997-0821
1997
Johnson, M.L.Moses, T.M., Reinita, I.M., Johnson, M.L., King, J.M.A contribution to understanding the effect of blue fluorescence on the appearance of diamonds.Gems and Gemology, Vol. 33, winter, pp. 244-259.GlobalDiamond fluoresence, Review
DS1998-0610
1998
Johnson, M.L.Hemphill, T.S., Reinitz, I.M., Johnson, M.L., ShigleyModeling the appearance of the round brilliant cut diamond: an analysis ofbrilliance.Gems and Gemology, Fall pp. 158-183.GlobalDiamond cutting
DS200512-0751
2004
Johnson, M.L.Moses, T.M., Johnson, M.L., Green, B., Blodgett, Cino, Geurts, Gilbertson, hemphill, King, Kornylak, ReinitzA foundation for grading the overall cut quality of round brilliant cut diamonds.Gems & Gemology, Vol. 40, 3, Fall, pp. 202-228.Diamond cutting
DS201506-0277
2015
Johnson, M.L.Johnson, M.L.Colour grading of synthetic moissanite.The Journal of Gemmology, Vol. 34, 5, pp. 384-385.TechnologyMoissanite
DS1988-0332
1988
Johnson, M.R.Johnson, M.R., Rust, I.C.Terranes, tectonostratigraphy and unconformity-bounded units: a review of current nomenclatureJournal of South. Afr. Geology, Vol. 91, No. 4, pp. 522-526. Database # 17958GlobalTerranes -nomenclature, Tectonics
DS1996-0694
1996
Johnson, M.R.Johnson, M.R., Van Vuuren, C.J., Shoko, U.Stratigraphy of the Karoo Supergroup in southern Africa: an overviewJournal of African Earth Sciences, Vol. 23, No. 1, pp. 3-16.South AfricaStratigraphy, Karoo Supergroup
DS200612-0645
2006
Johnson, M.R.Johnson, M.R., Anhaeusser, C.R., Thomas, R.J.The geology of South Africa. Chapter 31 Kimberlites by E.M.W. SkinnerCouncil of Geoscience and Geological Society of South Africa joint venture, anhaeusserc @geosciences.wits.ac.zaAfrica, South AfricaBook - Archean, Proterozoic, Phanerozoic, general
DS200712-0156
2007
Johnson, M.R.Cawood, P.A., Johnson, M.R., Nemchin, A.A.Early Paleozoic orogenesis along the Indian margin of Gondwana: tectonic response to Gondwana assembly.Earth and Planetary Science Letters, Vol. 255, 1-2, pp. 70-84.IndiaTectonics
DS2002-0784
2002
Johnson, M.R.W.Johnson, M.R.W.Shortening budgets and the role of continental subduction during the India Asia collision.Earth Science Reviews, Vol. 59, 1-4, Nov. pp. 101-23.India, AsiaSubduction, Tectonics
DS1991-0804
1991
Johnson, M.S.Johnson, M.S., Sides, A.Environmental assessment of new mining projects- code of practice for appointment and management of environmental consultantsInstitute of Mining and Metallurgy (IMM) Minerals Industry International, September pp. 13-18GlobalEconomics, Law-environmental
DS200412-0920
2004
Johnson, N.Johnson, N., Lilja, N., Ashby, J.A., Garcia, J.A.The practice of participatory research and gender analysis in natural resource management.Natural Resources Forum, Vol. 28, 3, pp. 189-200.GlobalResource management - not specific to diamonds
DS2002-1253
2002
Johnson, O.Petersen, O.V., Niedermayr, G., Johnson, O., Gault, R.Lovdarite from the Ilmaussaq alkaline complex, South GreenlandNeues Jahrbuch Mineralogy Monatsche, Vol.14, 1, pp. 23-30.GreenlandAlkaline - mineralogy
DS1995-1223
1995
Johnson, O.H.Medaris, L.G., Beard, B.L., Johnson, O.H., Valley, J.M.Garnet pyroxenite and eclogite in the Bohemian Massif -geochemical evidence for Variscan recycling.Geologische Rundschau, Vol. 84, No. 3, Sept. pp. 489-505.GermanyEclogites, Subduction
DS200712-0738
2007
Johnson, P.Moe, K.S., Johnson, P., Jang-Green, H.Translucent greenish yellow diamonds.Gems & Gemology, Vol. 43, 1, pp. 50-53.TechnologyDiamond morphology
DS201012-0833
2010
Johnson, P.Wang, W., Doering, P., Tower, J., Lu, R., Eaton-Magana, S., Johnson, P., Emerson, E., Moses, T.M.Strongly coloured pink CVD lab grown diamonds. A new generation of CVD lab-grown diamonds from Apollo Diamond Inc.Gems & Gemology, Vol. 46, 1, Spring pp. 4-17.TechnologyCVD Pink synthetics
DS201112-0485
2011
Johnson, P.Johnson, P.Pink HPHT synthetic diamonds - a new coloration technique.GIA International Symposium 2011, Gems & Gemology, Summer poster abstract session p.133-4TechnologyDiamonds - synthesis
DS201212-0761
2012
Johnson, P.Wang, W., D'Haenens-Johansson, U.F.S., Johnson, P., Moe, K.S., Emerson, E., Newton, M., Moses, T.M.CVD synthetic diamonds from Gemesis Corp.Gems & Gemology, Vol. 48, 2, summer pp. 80-97.TechnologyGemesis
DS201212-0762
2012
Johnson, P.Wang, W., D'Haenens-Johansson, U.F.S., Johnson, P., Soe Moe, K., Emerson, E., Newton, M., Moses, T.M.CVD synthetic diamodns from Gemesis Corp.Gems & Gemology, Vol. 48, 2, Summer pp. 80-97.TechnologyGemesis
DS201312-0954
2012
Johnson, P.Wang, W., D'Haenens-Johansson, U.F.S., Johnson, P., Soe Moe, K., Emerson, E., Newton, M.E., Moses, T.M.CVD synthetic diamonds from Gemesis Corp.Gems & Gemology, Vol. 48, , summer pp. 80-97.TechnologyGemesis
DS201412-0186
2014
Johnson, P.D'Haenens-Johansson, U.F.S., Soe Moe, K., Johnson, P., Yan Wong, S., Lu, R., Wang, W.Near-colorless HPHT synthetic diamonds from AOTC group.Gems & Gemology, Vol. 50, 1, Spring, pp. 30-45.TechnologySynthetic diamonds
DS201510-1774
2015
Johnson, P.Johnson, P., Moe, K.S., D'Haenens-Johansson, U., Rzhevskii, A.Discovery and distrbution of the [SI-V] defect in HPHT-grown gem quality diamonds.GSA Annual Meeting, Paper 300-12, 1p. Abstract only BoothTechnologySynthetic diamonds

Abstract: Defect of [Si-V]- is common in CVD synthetic diamonds, and its occurrence was also reported in some rare natural diamonds (Breeding and Wang, 2008). It is an important feature employed for gem diamond identification, and also has great potential for applications in industry. However little is known about how the silicon impurity gets into diamond lattice either in synthetic or natural diamonds. In this study, we discovered the occurrence of [Si-V]- in HPHT synthetic diamonds and the correlation between its precipitation and diamond growth sectors was successfully determined. Total 20 samples, HPHT grown diamond wafers from NDT (New Diamond Technology) were studied in addition to one type IIb HPHT synthetic diamond submitted to GIA Laboratory for grading. Distributions of defects in these samples were carefully mapped using infrared microscopy at room temperature and an imaging Raman microscope at liquid nitrogen temperature. Defect of [Si-V]- has doublet emissions at 736.6/736.9 nm (Clark et al., 1995), and can be effectively excited using 633 nm laser. Analyses were conducted at Liquid Nitrogen temperature as the detection of the Si related emissions peak is temperature dependent (Feng and Schwartz 1993). Additionally, the solvent catalysts used in the HPHT methods to grow synthetic diamond either intentionally or unintentionally contain nickel in varying quantities. Nickel impurity creates optical centers which emit a doublet peak at 882.6/884.3nm, and can be easily excited using 780 nm laser. The [SiV]- is clearly observed in only certain growth sectors of the synthetic crystal and the distribution is not homogeneous. By comparing the two acquired maps one acquired at 633nm excitation showing the [Si-V]- distribution and one acquired with 780nm excitation showing the nickel defect distribution, it was found that the [Si-V]- is confined to the same growth sector as Ni related defect with higher concentrations/intensity at the edges of these sectors. Since it is well known that the Ni defect is confined exclusively to the octahedral growth sectors {111} of diamond (Lawson et al., 1993), this study for the first time confirmed that [Si-V]- is confined to the {111} octahedral growth sectors. This new discovery leads to discussion as to the incorporation of silicon in diamond and the relationship to other impurities.
DS201510-1789
2015
Johnson, P.Moe, K.S., Yang, J-S, Johnson, P., Xu, X., Wang, W.Microdiamonds in chromitite and peridotite. Type 1aB and 1bGSA Annual Meeting, Paper 300-5, 1p. Abstract only BoothRussiaSpectroscopy
DS201512-1910
2015
Johnson, P.D'Haenens-Johansson, U.F.S., Katrusha, A., Moe, K.S., Johnson, P., Wang, W.Large colorless HPHT synthetic diamonds from new diamond technology. Using spectroscopic and gemological analysis.Gems & Gemology, Vol. 51, 3, pp. 260-79.TechnologySynthetics

Abstract: The Russian company New Diamond Technology is producing colorless and near-colorless HPHT-grown synthetic diamonds for the gem trade. Forty-four faceted samples synthesized using modified cubic presses were analyzed using a combination of spectroscopic and gemological techniques to characterize the quality of the material and determine the means of distinguishing them from natural, treated, and alternative laboratory-grown diamonds. These samples, with weights ranging from 0.20 to 5.11 ct, had color grades from D to K and clarity grades from IF to I2. Importantly, 89% were classified as colorless (D-F), demonstrating that HPHT growth methods can be used to routinely achieve these color grades. Infrared absorption analysis showed that all were either type IIa or weak type IIb, and photoluminescence spectroscopy revealed that they contained Ni-, Si-, or N-related defects. Their fluorescence and phosphorescence behavior was investigated using ultraviolet excitation from a long-wave/short-wave UV lamp, a DiamondView instrument, and a phosphorescence spectrometer. Key features that reveal the samples’ HPHT synthetic origin are described.
DS201608-1414
2016
Johnson, P.Johnson, P., Moe, K.S., Zaitsev, A.M.Treated hydrogen rich diamonds.GSA Annual Meeting, Abstract, Poster 1p.TechnologyBlack diamond

Abstract: Black diamonds with poor transparency due to an intensity of mineral inclusions and fractures are routinely traded in the gem market today. Although the inclusions and fractures are of natural origin this type of diamond is often heated to create a more uniform black color by further graphitizing these inclusions and fractures. Graphitization is often prominent at these fractures resulting in poor quality heavily fractured material. After nitrogen hydrogen is the most common impurity in natural diamond and is often responsible for a gem quality diamonds color. Color in diamond related or attributed to the hydrogen impurity can range from brown to green and gray. These colors are often undesirable to the gem trade and consumers. Recently GIA laboratories have seen a lot of faceted “Black” diamonds (graded as Fancy Black on GIA’s color scale) for identification. These diamonds are hydrogen rich and it is suspected that this material is treated (heated). Probably unattractive grayish green brown material that is virtually worthless in the gem trade before treatment. With such large quantities of this treated material available a serious threat and identification problem is posed to the Gem Diamond industry. Three faceted round cut hydrogen rich diamonds (0.30, 0.52 and 0.58 carats) colored by dense hydrogen clouds giving them a murky grayish appearance have been documented and systematically heated. A black color identical to that of the suspected treated black diamonds has been achieved, thus confirming this coloration treatment and new identification techniques to detect it. These treated black diamonds have a uniform color and lack the heavy fracturing and surface graphitization of typical treated black diamonds. Heating conditions and techniques will be discussed and we report on this new type of material and gem stone treatment.
DS201610-1876
2016
Johnson, P.Johnson, P., Kyaw, S., Zaitsev, A.M.Treated hydrogen rich diamonds.GSA Annual Meeting, 1/2p. abstractTechnologyBlack diamond
DS201610-1916
2016
Johnson, P.Wang, W., Johnson, P., D'Haeniens-Johansson, U., Loudin, L.Distribution of [SI-V] defect in natural type Iia diamonds.GSA Annual Meeting, 1/2p. abstractTechnologyDiamond inclusions

Abstract: [Si-V]- is a well-known defect in diamond. It has a great potential in electronics application and also is a very important feature for gem diamond identification in separating natural from synthetic. It is common in CVD diamonds (Martineau et al., 2004), can be doped into HPHT synthetic diamonds (Sittas, et al., 1996), and also occurs in natural type IIa diamonds (Breeding and Wang, 2008). Recent study of [Si-V]- distribution (emissions at 736.6 and 736.9 nm) in HPHT synthetic diamonds confirmed that it was concentrated in the {111} growth sectors. Identical distribution pattern of Nii+, which has doublet emissions at 882.1 and 883.7 nm, was observed (Johnson et al., 2015), strongly indicating that [Si-V]- and Nii+ have the same behavior during HPHT diamond growth. However, little is known how [Si-V]- is incorporated in natural diamond lattice. In this report, we studied the distribution of [Si-V]- defect in natural diamonds and its correlation with other emissions (defects). Seven natural type IIa gem diamonds were analyzed in this study. A common feature of this group of diamonds is occurrence of euhedral olivine inclusions, which is very rare among natural type IIa diamonds and good evidence that these IIa diamonds were formed in the lithospheric mantle. Occurrence of [Si-V]- in these stones were detected among enormous natural type IIa diamonds routinely analyzed in GIA laboratories. Distribution of [Si-V]-, Nii+ and many other emissions were mapped over the table faces using various laser excitations at liquid nitrogen temperature. It was found that intensities of [Si-V]- emission varied significantly over a small area. The distribution patterns were irregular and changed from stone to stone. Distribution of Nii+ emissions showed irregular patterns, but entirely different from that of [Si-V]-. There is no correlation in spatial distribution of these two defects in natural type IIa diamonds, in drastic contract to that observed in HPHT synthetics. Possible causes of the contrast behaviors of [Si-V]- distributions in natural and HPHT synthetic diamonds, and their implications in diamond formation and gem diamond identification will be discussed.
DS201705-0858
2017
Johnson, P.Moe, K., Yang, J-S., Johnson, P., Wang, W.Spectroscopic analysis of microdiamonds in ophiolitic chromitite and peridotite.Lithosphere, 9p.Asia, Tibet, Russia, UralsMicrodiamonds

Abstract: Microdiamonds ?200 ?m in size, occurring in ophiolitic chromitites and peridotites, have been reported in recent years. Owing to their unusual geological formation, there are several debates about their origin. We studied 30 microdiamonds from 3 sources: (1) chromitite ore in Luobusa, Tibet; (2) peridotite in Luobusa, Tibet; and (3) chromitite ore in Ray-Iz, polar Ural Mountains, Russia. They are translucent, yellow to greenish-yellow diamonds with a cubo-octahedral polycrystalline or single crystal with partial cubo-octahedral form. Infrared (IR) spectra revealed that these diamonds are type Ib (i.e., diamonds containing neutrally charged single substitutional nitrogen atoms, Ns0, known as the C center) with unknown broad bands observed in the one-phonon region. They contain fluid inclusions, such as water, carbonates, silicates, hydrocarbons, and solid CO2. We also identified additional microinclusions, such as chromite, magnetite, feldspar (albite), moissanite, hematite, and magnesiochromite, using a Raman microscope. Photoluminescence (PL) spectra measured at liquid nitrogen temperature suggest that these diamonds contain nitrogen-vacancy, nickel, and H2 center defects. We compare them with high-pressure-high-temperature (HPHT) synthetic industrial diamond grits. Although there are similarities between microdiamonds and HPHT synthetic diamonds, major differences in the IR, Raman, and PL spectra confirm that these microdiamonds are of natural origin. Spectral characteristics suggest that their geological formation is different but unique compared to that of natural gem-quality diamonds. Although these microdiamonds are not commercially important, they are geologically important in that they provide an understanding of a new diamond genesis.
DS201804-0738
2017
Johnson, P.Smith, E.M., Johnson, P.Lizard skin on deformed diamondGems & Gemology Lab Notes, Vol. 53, 4, p. 460.Technologydiamond crystallography

Abstract: Facets that are nearly parallel to a diamond’s octahedral crystal plane often develop a wavy, rippled appearance called "lizard skin" during polishing (e.g., J.I. Koivula, The MicroWorld of Diamonds, Gemworld International, Northbrook, Illinois, 2000, p. 63). The term is also used more broadly to describe any bumpy, uneven surface texture that develops on polished diamond facets. It is often attributed to polishing off-grain. Recently, GIA’s New York lab encountered a 2.67 ct type IIa diamond (figure 1, left) with especially prominent lizard skin texture on multiple facets (figure 1, center and right). In this case, the texture appears to have developed due to a preexisting deformation fabric or structure inherent to the diamond itself, rather than merely as a consequence of poor polishing technique.
DS201901-0048
2018
Johnson, P.Moe, K.S., Johnson, P.Type Ib- dominant mixed type diamond with cuboctahedral growth structure: a rare diamond formation.Gems & Gemology, Sixth International Gemological Symposium Vol. 54, 3, 1p. Abstract p. 307-8.Globaldiamond morphology

Abstract: Type Ib-dominant mixed-type diamonds (Ib-IaA) can be formed by multiple growth events (Titkov et al., 2015; Smit et al., 2018). In this study, we report on a 0.41 ct Fancy Dark brown gem - quality diamond that formed in a single growth event. It is a type Ib-IaA with a C defect (single-substitutional nitrogen atom) concentration up to 21 ppm. The Fourier-transform infrared (FTIR) peaks of the H1a and H1b defects (figure 1, left) suggest that this diamond was irradiated and annealed to achieve a Fancy color grade. The cuboctahedral structure can be observed in the DiamondView images (figure 1, right), which show reddish orange submitted to GIA for screening, we found that more than 70% of them contained a typical mineral assemblage from the sublithosphere. Jeffbenite (TAPP), majorite garnet, enstatite, and ferropericlase have been observed, which could be retrograde products of former bridgmanite. CaSiO3-walstromite with larnite and titanite is the dominant phase present in approximately 40% of all diamond samples. Direct evidence from oxygen isotope ratios measured by secondary ion mass spectrometry, or SIMS, (?18OVSMOWin the range +10.7 to +12.5‰) of CaSiO3-walstromite with coexisting larnite and titanite that retrograde from CaSiO3-perovskite suggest that hydrothermally altered oceanic basalt can subduct to depths of >410 km in the transition zone. Incorporation of materials from subducted altered oceanic crust into the deep mantle produced diamond inclusions that have both lower mantle and subduction signatures. Ca(Si,Al)O3-perovskite was observed with a high concentration of rare earth elements (>5 wt.%) that could be enriched under P-Tconditions in the lower mantle. Evidence from ringwoodite with a hydroxide bond, coexisting tuite and apatite, precipitates of an NH3phase, and cohenite with trace amounts of Cl imply that the subducted brines can potentially introduce hydrous fluid to the bottom of the transition zone. In the diamonds with subducted materials, the increasing carbon isotope ratio from the core to the rim region detected by SIMS (?13C from -5.5‰ to -4‰) suggests that an oxidized carbonate-dominated fluid was associated with recycling of the subducted hydrous material. The deep subduction played an important role in balancing redox exchange with the reduced lower mantle indicated by precipitated iron nanoparticles and coexisting hydrocarbons and carbonate phases.
DS202108-1280
2021
Johnson, P.Eaton-Magana, S., Johnson, P., Barrie, E., Harinova, M.Bicolor rough diamond crystals. ( pink)Gems & Gemology , Vol. 57, 1, pp. 53-55.Australiadiamond colour
DS202110-1633
2021
Johnson, P.Persaud, S., Galati, A., Johnson, P.Colorful inclusions in diamond.Gems & Gemology, Vol. 57, 2, pp. 158-159. gia.edu/gems-gemologyUnited States, Californiadiamond inclusions
DS1975-0302
1976
Johnson, P.A.Johnson, P.A.Exploration for Kimberlites, a Possible Source of DiamondsBsc. Thesis, University Toronto, 52P.CanadaBlank
DS1990-0773
1990
Johnson, P.R.Johnson, P.R., Zietz, I., Bond, K.R.U.S. West coast revisited: an aeromagnetic perspectiveGeology, Vol. 18, No. 4, April pp. 323-335California, CordilleraGeophysics -magnetics, Lineaments
DS1990-1636
1990
Johnson, P.R.Zietz, I., Johnson, P.R., Wilson, G.V.Aeromagnetic dat a and basement structures in AlabamaGeological Society of America (GSA) Annual Meeting, Abstracts, Vol. 22, No. 7, p. A231GlobalGeophysics -aeromagnetics, Structure
DS1994-0849
1994
Johnson, P.R.Johnson, P.R., Zeitz, I., Thomas, W.A.Possible Neoproterozoic-early Paleozoic grabens in Mississippi, Alabama, and Tennessee.Geology, Vol. 22, No. 1, January pp. 11-14.Mississippi, Alabama, TennesseeTectonics, Grabens
DS2001-0539
2001
Johnson, P.R.Johnson, P.R., Kattan, F.Oblique sinistral transpression in Arabian shield: the timing and kinematics of a Neoproterozoic suture zone.Precambrian Research, Vol. 107, No. 1-2, Mar. 30, pp. 117-GlobalTectonics
DS200412-0921
2003
Johnson, P.R.Johnson, P.R., Woldehaimanot, B.Development of the Arabian Nubian shield: perspectives on accretion and deformation in the northern East African Orogen and theProterozoic East Gondwana: Supercontinent assembly and Breakup. Ed. Yoshida , Geological Society of London Spe, No. 206, pp. 289-326.AfricaPlume, tectonics
DS200512-0732
2005
Johnson, P.T.Misra, S., Johnson, P.T.Geochronological constraints on evolution of Singhbhum mobile belt and associated basic volcanics of eastern Indian Shield.Gondwana Research, Vol. 8, 2, pp. 129-142.IndiaSinghbhum-Orissa Craton, Archean crustal growth
DS1989-0541
1989
Johnson, R.A.Greene, L.C., Johnson, R.A.Interpretation of gravity and seismic relection dat a beneath the ChalbiEos, Vol. 70, No. 43, October 24, p. 1336. AbstractKenyaTectonics, Rift
DS1991-0604
1991
Johnson, R.A.Greene, L.C., Richards, D.R., Johnson, R.A.Crustal structure and tectonic evolution of the Anza rift, northern SOURCE[ TectonophysicsTectonophysics, Vol. 197, No. 2-4, November pp. 203-212KenyaTectonics, Rift system
DS1970-0584
1972
Johnson, R.B.Puckett, J.L., Mccallum, M.E., Johnson, R.B., Filson, R.H.Preliminary Geophysical Evaluation of Kimberlitic Diatremesin Northern Colorado and Southern Wyoming.Geological Society of America (GSA), Vol. 4, No. 6, P. 403, (abstract.).Colorado, Wyoming, United States, State Line, Rocky MountainsKimberlite, Geophysics
DS1982-0132
1982
Johnson, R.B.Carlson, J.A., Johnson, R.B., Mccallum, M.E., Padgett, J.P.Evaluation of Geophysical Techniques for Diatreme Delineation in the Colorado-Wyoming Kimberlite Province. #1Proceedings of Third International Kimberlite Conference, TERRA, Vol. 2, No. 3, P. 203, (abstract.).United States, Colorado, Wyoming, State Line, Rocky MountainsKimberlite, Geophysics, Groundmag, Electromagnetic, Radioactivity
DS1984-0180
1984
Johnson, R.B.Carlson, J.A., Johnson, R.B., Mccallum, M.E., Campbell, D.L.P.Evaluation of Geophysical Techniques for Diatreme Delineation in the Colorado Wyoming Kimberlite Province. #2Proceedings of Third International Kimberlite Conference, Vol. 1, PP. 21-32.United States, Colorado, Wyoming, State Line, Rocky MountainsGeophysics, Kimberlite, Electromagnetic, Ground, Magnetics, Vlf
DS1988-0723
1988
Johnson, R.J.E.Van der Voo, R., Johnson, R.J.E.Displaced terranes in the northern AppalachiansGeological Society of America (GSA) Abstract Volume, Vol. 20, No. 3, February p. 239-240. abstractNewfoundlandBlank
DS1990-1496
1990
Johnson, R.J.E.Van der Pluijm, B.A., Johnson, R.J.E., Van der Voo, R.Early Paleozoic paleogeography and accretionary history of the NewfoundlandAppalachiansGeology, Vol. 18, No. 9, September pp. 898-901NewfoundlandTectonics -accretion, Paleogeography
DS1960-0028
1960
Johnson, R.L.Cox, K.G., Johnson, R.L., Monkman, L.J., Vail, J.R.Progress of Investigations in Southeast Southern RhodesiaLeeds University Research Institute of African Geology Annual Report, APP. C, Vol. 4, PP. 26-28.ZimbabweGeology, Related Rocks
DS1960-0135
1961
Johnson, R.L.Cox, K.G., Vail, J.R., Monkman, L.J., Johnson, R.L.Karroo Igneous Activity and Tectonics in Southeast Southern Rhodesia.Nature., Vol. 190, No. 4770, P. 40.; P. 77.ZimbabweGeology, Related Rocks, Tectonics
DS1960-0158
1961
Johnson, R.L.Johnson, R.L.The Geology of the Doroga and Shawa Carbonatite Complexes, Southern Rhodesia.Geological Society of South Africa Transactions, Vol. 64, PP. 101-145.ZimbabweGeology, Related Rocks
DS1960-0281
1962
Johnson, R.L.Nicholson, L.O., Burger, A.J., Johnson, R.L.The Age of the Shawa Carbonatite ComplexGeological Society of South Africa Transactions, Vol. 65, PT. 1, PP. 293-294.ZimbabweGeology, Related Rocks, Geochronology
DS1960-0465
1964
Johnson, R.L.Johnson, R.L.The Structure of the Marumbe Ring Complex Nuanetsi Igneous Province, Southern Rhodesia.Geology Magazine, Vol. 101, No. 3, PP. 274-281.ZimbabweGeology, Related Rocks
DS1960-0532
1965
Johnson, R.L.Cox, K.G., Johnson, R.L., Monkman, L.J.The Geology of the Nuanetsi Igneous ProvinceRoyal Society. PHIL. Transactions, SERIES A Vol. 257, PP. 71-218.ZimbabweGeology, Related Rocks
DS1960-0684
1966
Johnson, R.L.Johnson, R.L.The Shawa and Dorowa Carbonatite Complexes: Features of The karroo Igneous Cycle of Southern Africa.In: Carbonatites, Tuttle, O.f.; Gittens, J. Editors, New Yor, PP. 205-224.ZimbabweGeology, Kimberley
DS1985-0545
1985
Johnson, R.W.Price, R.C., Johnson, R.W., Gray, C.M., Frey, F.A.Geochemistry of Phonolites and Trachytes from the Summit Region of Mt. Kenya.Contributions to Mineralogy and Petrology, Vol. 89, No. 4, PP. 394-409.East Africa, KenyaGeochemistry
DS1992-0798
1992
Johnson, R.W.Johnson, R.W.Intraplate volcanism in eastern Australia and New ZealandCambridge, 432p. approx. $ 100.00 United StatesAustralia, New Zealandvolcanism., Book -table of contents
DS1950-0219
1955
Johnson, R.W.JR.Johnson, R.W.JR.Aeromagnetic Observations in Central Western VirginiaAppalachian Geological Society Guidebook, MAY, P. 40.United States, Appalachia, VirginiaGeophysics
DS1950-0220
1955
Johnson, R.W.JR.Johnson, R.W.JR., Milton, C.Dike Rocks of Central Western VirginiaGeological Society of America (GSA) Bulletin., Vol. 66, PP. 1689-1690.United States, Appalachia, Virginia, Highland, GeorgiaKimberlite, Geophysics
DS1950-0477
1959
Johnson, R.W.JR.Johnson, R.W.JR.Aeromagnetic Survey of a Mica Peridotite in Union County, Tennessee.Geological Society of America (GSA) Bulletin., Vol. 70, No. 12, PT. 2, PP. 1745-1765.United States, Appalachia, TennesseeGeophysics
DS1960-0159
1961
Johnson, R.W.JR.Johnson, R.W.JR.Dimensions and Attitude of the Peridotite in Clark Hollow Union County, Tennessee: an Aeromagnetic Study.Southeastern Geology, Vol. 2, No. 3, PP. 137-154.United States, Tennessee, Central StatesKimberlite, Geophysics, Airmag
DS1970-0278
1971
Johnson, R.W.Jr.Dennison, J.M., Johnson, R.W.Jr.Tertiary Intrusions and Associated Phenomena Near the Thirty Eighth Parallel Fracture Zone in Virginia and West Virginia.Geological Society of America (GSA) Bulletin., Vol. 82, PP. 501-508.United States, Appalachia, VirginiaRelated Rocks, Geology
DS1970-0321
1971
Johnson, R.W.JR.Johnson, R.W.JR., Milton, C., Dennison, J.M.Field Trip to the Igneous Rocks of Augusta, Rockingham and Highland and bath Counties, Virginia.Virginia Div. Min. Res. Inf. Circular, No. 16, 68P.United States, Appalachia, VirginiaGeology, Fieldtrip
DS1975-1085
1979
Johnson, R.W.JR.Johnson, R.W.JR., Hildenbrand, T.G., Haygood, C., Kunselman, P.Magnetic Anomaly Map of the Greater New Madrid Seismic ZoneEos, Vol. 61, No. 5, PP. 47-48. (abstract.).GlobalMid-continent
DS1980-0184
1980
Johnson, R.W.JR.Johnson, R.W.JR., et al.Aeromagnetic Map of the East Central Midcontinent of the United States.U.s. Nucl. Regul. Comm. Report Nureg/cr-1662, 12P.GlobalMid-continent
DS200412-0345
2003
Johnson, S.Collins, A.S., Johnson, S., Fitzimmona, I.C.W., Powell, C.McA., Hulscher, B., Abello, J., Razakamana, T.Neoproterozoic deformation in central Madagascar: a structural section through part of the East African orogen.Proterozoic East Gondwana: Supercontinent assembly and Breakup. Ed. Yoshida , Geological Society of London Spe, No. 206, pp. 363-380.Africa, MadagascarPlume, tectonics
DS200412-1553
2003
Johnson, S.Pisarevsky, S.A., Wingate, M.T.D., Powell, C.McA., Johnson, S., Evans, D.A.D.Models of Rodinia assembly and fragmentation.Proterozoic East Gondwana: Supercontinent assembly and Breakup. Ed. Yoshida , Geological Society of London Spe, No. 206, pp. 35-56.GondwanaPlume, tectonics
DS2001-0540
2001
Johnson, S.E.Johnson, S.E., Albertz, M., Paterson, S.R.Growth rates of dike fed plutons: are they compatible with observations In the middle and upper crust?Geology, Vol. 29, No. 8, Aug. pp. 727-30.MantleDikes, diapirs, plutons
DS2001-0733
2001
Johnson, S.E.Marschallinger, R., Johnson, S.E.Presenting 3 D models of geological materials on the World Wide WebComputers and Geosciences, Vol. 27, No. 4, pp. 467-76.GlobalComputer - models ?
DS200812-0521
2008
Johnson, S.E.Jin, Z-H., Johnson, S.E.Magma driven multiple dike propogation and fracture toughness of crustal rocks.Journal of Geophysical Research, Vol. 113, B03206MantleMagmatism - dykes
DS1960-0845
1967
Johnson, S.H.Johnson, S.H.Seismic Investigation of the Mid-continent Gravity High in Southeastern Minnesota.Msc. Thesis, University Minnesota., GlobalMid-continent, Geophysics
DS1960-0846
1967
Johnson, S.H.Johnson, S.H., Farnham, P.R.Refraction Seismic Surveys on the Mid-continent Gravity Anomaly in Minnesota and Wisconsin.Institute LAKE SUPERIOR GEOLOGY, 13TH. MEETING HELD EAST LANSING, P. 24, (abstract.).GlobalMid-continent, Geophysics
DS1970-0151
1970
Johnson, S.H.Mooney, H.M., Craddock, C.E., Farnham, P.R., Johnson, S.H., Vol.Refraction Seismic Investigations of the Northern Mid-continent Gravity High.Journal of GEOPHYSICAL RESEARCH, Vol. 75, No. 26, PP. 5056-5086.GlobalMid Continent
DS1998-1092
1998
Johnson, S.P.Oliver, G.J.H., Johnson, S.P., Williams, I.S., HerdRelict 1.4 Ga oceanic crust in the Zambezi Valley: evidence Mesoproterozoic supercontinental fragmentationGeology, Vol. 26, No. 6, June pp. 571-3ZimbabweOrogenic belts, Archean Craton, Rodinia, tectonics, Chewore ophiolite
DS200512-0483
2005
Johnson, S.P.Johnson, S.P., Rivers, T., De Waele, B.A review of Mesoproterozoic to early Paleozooic magmatic and tectonothermal history of south central Africa: implications for Rodinia and Gondwana.Journal of the Geological Society, Vol. 162, 3, pp. 433-450.Africa, GondwanaMagmatism, geothermometry
DS201704-0634
2017
Johnson, S.P.Korhonen, F.J., Johnson, S.P., Wingate, M.T.D., Fletcher, I.R., Dunkley, D.J., Roberts, M.P., Sheppard, S., Muhling, J.R., Rasmussen, B.Radiogenic heating and craton-margin plate stresses as drivers for intraplate orogeny.Journal of Metamorphic Geology, in press availableMantleCraton

Abstract: The Proterozoic belts that occur along the margins of the West Australian Craton, as well as those in intraplate settings, generally share similar geological histories that suggest a common plate-margin driver for orogeny. However, the thermal drivers for intraplate orogenesis are generally more poorly understood. The Mutherbukin Tectonic Event records a protracted period of Mesoproterozoic reworking of the Capricorn Orogen and offers significant insight into both the tectonic drivers and heat sources of long-lived intraplate orogens. Mineral assemblages and tectonic fabrics related to this event occur within a 50 km-wide fault-bound corridor in the central part of the Gascoyne Province in Western Australia. This zone preserves a crustal profile, with greenschist facies rocks in the north grading to upper amphibolite facies rocks in the south. The P- T-t evolution of 13 samples from 10 localities across the Mutherbukin Zone is investigated using phase equilibria modelling integrated with in situ U-Pb monazite and zircon geochronology. Garnet chemistry from selected samples is used to further refine the P-T history and shows that the dominant events recorded in this zone are prolonged D1 transpression between c. 1320 and 1270 Ma, followed by D2 transtension from c. 1210 to 1170 Ma. Peak metamorphic conditions in the mid-crust reached >650 °C and 4.4-7 kbar at c. 1210-1200 Ma. Most samples record a single clockwise P-T evolution during this event, although some samples might have experienced multiple perturbations. The heat source for metamorphism was primarily conductive heating of radiogenic mid- and upper crust, derived from earlier crustal differentiation events. This crust was thickened during D1 transpression, although the thermal effects persisted longer than the deformation event. Peak metamorphism was terminated by D2 transtension at c. 1210 Ma, with subsequent cooling driven by thinning of the radiogenic crust. The coincidence of a sedimentary basin acting as a thermal lid and a highly radiogenic mid-crustal batholith restricted to the Mutherbukin Zone accounts for reworking being confined to a discrete crustal corridor. Our results show that radiogenic regions in the shallow to mid crust can elevate the thermal gradient and localize deformation, causing the crust to be more responsive to far-field stresses. The Mutherbukin Tectonic Event in the Capricorn Orogen was synchronous with numerous Mesoproterozoic events around the West Australian Craton, suggesting that thick cratonic roots play an important role in propagating stresses generated at distant plate boundaries.
DS201709-2019
2017
Johnson, S.P.Kohonen, F.J., Johnson, S.P., Wingate, M.T.D., Kirkland, C.L., Fletcher, I.R., Dunkley, D.J., Roberts, M.P., Sheppard, S., Muhling, J.R., Rasmussen, B.Radiogenic heating and craton margin plate stresses as drivers for intraplate orogeny.Journal of Metamorphic Geology, Vol. 35, 6, pp. 631-661.Mantlegeothermometry

Abstract: The Proterozoic belts that occur along the margins of the West Australian Craton, as well as those in intraplate settings, generally share similar geological histories that suggest a common plate-margin driver for orogeny. However, the thermal drivers for intraplate orogenesis are more poorly understood. The Mutherbukin Tectonic Event records a protracted period of Mesoproterozoic reworking of the Capricorn Orogen and offers significant insight into both the tectonic drivers and heat sources of long-lived intraplate orogens. Mineral assemblages and tectonic fabrics related to this event occur within a 50 km-wide fault-bound corridor in the central part of the Gascoyne Province in Western Australia. This zone preserves a crustal profile, with greenschist facies rocks in the north grading to upper amphibolite facies rocks in the south. The P–T–t evolution of 13 samples from 10 localities across the Mutherbukin Zone is investigated using phase equilibria modelling integrated with in situ U–Pb monazite and zircon geochronology. Garnet chemistry from selected samples is used to further refine the P–T history and shows that the dominant events recorded in this zone are prolonged D1 transpression between c. 1,320 and 1,270 Ma, followed by D2 transtension from c. 1,210 to 1,170 Ma. Peak metamorphic conditions in the mid-crust reached >650°C and 4.4–7 kbar at c. 1,210–1,200 Ma. Most samples record a single clockwise P–T evolution during this event, although some samples might have experienced multiple perturbations. The heat source for metamorphism was primarily conductive heating of radiogenic mid- and upper crust, derived from earlier crustal differentiation events. This crust was thickened during D1 transpression, although the thermal effects persisted longer than the deformation event. Peak metamorphism was terminated by D2 transtension at c. 1,210 Ma, with subsequent cooling driven by thinning of the radiogenic crust. The coincidence of a sedimentary basin acting as a thermal lid and a highly radiogenic mid-crustal batholith restricted to the Mutherbukin Zone accounts for reworking being confined to a discrete crustal corridor. Our results show that radiogenic regions in the shallow to mid crust can elevate the thermal gradient and localize deformation, causing the crust to be more responsive to far-field stresses. The Mutherbukin Tectonic Event in the Capricorn Orogen was synchronous with numerous Mesoproterozoic events around the West Australian Craton, suggesting that thick cratonic roots play an important role in propagating stresses generated at distant plate boundaries.
DS2002-0785
2002
Johnson, S.T.Johnson, S.T., McCourt, S., Bisnath, A., Mitchell, A.A.The Tugela Terrane Natal belt: Kibaran magmatism and tectonism along the southeast margin of the Kaapvaal Craton.Geological Society of South Africa, Vol. 105, No. 1, pp. 1-14.South AfricaCraton - tectonics
DS201905-1020
2019
Johnson, T.Cesare, B., Nestola, F., Mugnaioli, E., Della Ventura, G., Peruzzo, L., Bartoli, O., Viti, C., Johnson, T., Erickson, T.I was not born cubic, said low temperature metamorphic garnet. Geophysical Research Abstracts EGRU2019-3091, Vol. 21, 3091, 1p.Europe, Alpsgarnet

Abstract: Garnet is the paradigmatic cubic mineral of metamorphic and igneous rocks, and is generally regarded as optically isotropic. Nonetheless, evident birefringence is observed, particularly in the rare CaFe 3+ hydrogarnets, which is attributed to the coexistence of two or more cubic phases. A weak birefringence, with rare examples of optical sector zoning, has also been documented in much more common Fe 2+-Mg-Mn garnets, but an adequate explanation for its cause is, so far, lacking. Here we show that optically anisotropic garnets are much more widespread than previously thought, both in blueschists and blueschist-facies rocks, as well as in lower greenschist-facies phyllites, but they are frequently overlooked when working with conventional, 30-µm-thick thin sections. Utilizing a multi-technique approach including optical microstructural analysis, BSEM, EMPA, EBSD, FTIR, TEM, EDT and single-crystal XRD, we demonstrate here that the birefringence in these garnets is related to their tetragonal symmetry, that it is not due to strain, and that crystals are twinned according to a merohedral law. We also show that the birefringent garnets from blueschists and phyllites are anhydrous, lacking any hydrogarnet component, and have compositions dominated by almandine (58-79%) and grossular (19-30%) with variable spessartine (0-21%) and very low pyrope (1-7%). Considering the widespread occurrence of optically anisotropic OH-free garnets in blueschists and phyllites, their common low-grade metamorphic origin, and the occurrence of optically isotropic garnets with similar Ca-rich almandine composition in higher-grade rocks, we conclude that garnet does not grow with cubic symmetry in low-temperature rocks (< 400 • C). The tetragonal structure appears to be typical of Fe-Ca-rich compositions, with very low Mg contents. Cubic but optically sector-zoned garnet in a lower amphibolite-facies metapelite from the eastern Alps suggests that preservation of tetragonal garnet is favored in rocks which did not progress to T> ?500 • C, where transition to the cubic form, accompanied by change of stable chemical composition, would take place. Our data show that the crystal-chemistry of garnet, its thermodynamics and, in turn, its use in unravelling petrogenetic processes in cold metamorphic environments need to be reassessed.
DS201909-2026
2019
Johnson, T.Brown, M., Johnson, T.Metamorphism and the evolution of subduction on Earth.American Mineralogist, Vol. 104, pp. 1065-1082.Mantlesubduction

Abstract: Subduction is a component of plate tectonics, which is widely accepted as having operated in a manner similar to the present-day back through the Phanerozoic Eon. However, whether Earth always had plate tectonics or, if not, when and how a globally linked network of narrow plate boundaries emerged are matters of ongoing debate. Earth's mantle may have been as much as 200-300 °C warmer in the Mesoarchean compared to the present day, which potentially required an alternative tectonic regime during part or all of the Archean Eon. Here we use a data set of the pressure (P), temperature (T), and age of metamorphic rocks from 564 localities that vary in age from the Paleoarchean to the Cenozoic to evaluate the petrogenesis and secular change of metamorphic rocks associated with subduction and collisional orogenesis at convergent plate boundaries. Based on the thermobaric ratio (T/P), metamorphic rocks are classified into three natural groups: high T/P type (T/P > 775 °C/GPa, mean T/P ~1105 °C/GPa), intermediate T/P type (T/P between 775 and 375 °C/GPa, mean T/P ~575 °C/GPa), and low T/P type (T/P < 375 °C/GPa, mean T/P ~255 °C/GPa). With reference to published thermal models of active subduction, we show that low T/P oceanic metamorphic rocks preserving peak pressures >2.5 GPa equilibrated at P-T conditions similar to those modeled for the uppermost oceanic crust in a wide range of active subduction environments. By contrast, those that have peak pressures <2.2 GPa may require exhumation under relatively warm conditions, which may indicate subduction of young oceanic lithosphere or exhumation during the initial stages of subduction. However, low T/P oceanic metamorphic rocks with peak pressures of 2.5-2.2 GPa were exhumed from depths where, in models of active subduction, the slab and overriding plate change from being decoupled (at lower P) to coupled (at higher P), possibly suggesting a causal relationship. In relation to secular change, the widespread appearance of low T/P metamorphism in the Neoproterozoic represents a “modern” style of cold collision and deep slab breakoff, whereas rare occurrences of low T/P metamorphism in the Paleoproterozoic may reveal atypical localized regions of cold collision. Low T/P metamorphism is not known from the Archean geological record, but the absence of blueschists in particular is unlikely to reflect secular change in the composition of the oceanic crust. In addition, the premise that the formation of lawsonite requires abnormally low thermal gradients and the postulate that oceanic subduction-related rocks register significantly lower maximum pressures than do continental subduction-related rocks, and imply different mechanisms of exhumation, are not supported. The widespread appearance of intermediate T/P and high T/P metamorphism at the beginning of the Neoarchean, and the subsequent development of a clear bimodality in tectono-thermal environments are interpreted to be evidence of the stabilization of subduction during a transition to a globally linked network of narrow plate boundaries and the emergence of plate tectonics.
DS201911-2514
2019
Johnson, T.Cesare, B., Nestola, F., Johnson, T., Mugnaioli, E., Della Ventura, G., Peruzzo, L., Bartoli, O., Viti, C., Erickson, T.Garnet, the archetypal cubic mineral, grows tetragonal.Nature Research, doi.org/10.1038/s41598-019-51214-9Mantlegarnet

Abstract: Garnet is the archetypal cubic mineral, occurring in a wide variety of rock types in Earth’s crust and upper mantle. Owing to its prevalence, durability and compositional diversity, garnet is used to investigate a broad range of geological processes. Although birefringence is a characteristic feature of rare Ca-Fe3+ garnet and Ca-rich hydrous garnet, the optical anisotropy that has occasionally been documented in common (that is, anhydrous Ca-Fe2+-Mg-Mn) garnet is generally attributed to internal strain of the cubic structure. Here we show that common garnet with a non-cubic (tetragonal) crystal structure is much more widespread than previously thought, occurring in low-temperature, high-pressure metamorphosed basalts (blueschists) from subduction zones and in low-grade metamorphosed mudstones (phyllites and schists) from orogenic belts. Indeed, a non-cubic symmetry appears to be typical of common garnet that forms at low temperatures (<450?°C), where it has a characteristic Fe-Ca-rich composition with very low Mg contents. We propose that, in most cases, garnet does not initially grow cubic. Our discovery indicates that the crystal chemistry and thermodynamic properties of garnet at low-temperature need to be re-assessed, with potential consequences for the application of garnet as an investigative tool in a broad range of geological environments.
DS202005-0723
2020
Johnson, T.Brown, M., Johnson, T., Gardiner, N.J.Plate tectonics and the Archean Earth.Annual Review of Earth and Planetary Sciences, Vol. 48, 30p. pdfMantlesubduction, metamorphism

Abstract: If we accept that a critical condition for plate tectonics is the creation and maintenance of a global network of narrow boundaries separating multiple plates, then to argue for plate tectonics during the Archean requires more than a local record of subduction. A case is made for plate tectonics back to the early Paleoproterozoic, when a cycle of breakup and collision led to formation of the supercontinent Columbia, and bimodal metamorphism is registered globally. Before this, less preserved crust and survivorship bias become greater concerns, and the geological record may yield only a lower limit on the emergence of plate tectonics. Higher mantle temperature in the Archean precluded or limited stable subduction, requiring a transition to plate tectonics from another tectonic mode. This transition is recorded by changes in geochemical proxies and interpreted based on numerical modeling. Improved understanding of the secular evolution of temperature and water in the mantle are key targets for future research. 1) Higher mantle temperature in the Archean precluded or limited stable subduction, requiring a transition to plate tectonics from another tectonic mode. 2) Plate tectonics can be demonstrated on Earth since the early Paleoproterozoic (since c. 2.2 Ga), but before the Proterozoic Earth's tectonic mode remains ambiguous. 3) The Mesoarchean to early Paleoproterozoic (3.2-2.3 Ga) represents a period of transition from an early tectonic mode (stagnant or sluggish lid) to plate tectonics. 4) The development of a global network of narrow boundaries separating multiple plates could have been kick-started by plume-induced subduction.
DS202007-1126
2020
Johnson, T.Brown, M., Johnson, T., Gardiner, N.J.Plate tectonics and the Archean Earth.Annual Review of Earth and Planetary Sciences, Vol. 48, 1, pp. 291-320.Mantletectonics

Abstract: If we accept that a critical condition for plate tectonics is the creation and maintenance of a global network of narrow boundaries separating multiple plates, then to argue for plate tectonics during the Archean requires more than a local record of subduction. A case is made for plate tectonics back to the early Paleoproterozoic, when a cycle of breakup and collision led to formation of the supercontinent Columbia, and bimodal metamorphism is registered globally. Before this, less preserved crust and survivorship bias become greater concerns, and the geological record may yield only a lower limit on the emergence of plate tectonics. Higher mantle temperature in the Archean precluded or limited stable subduction, requiring a transition to plate tectonics from another tectonic mode. This transition is recorded by changes in geochemical proxies and interpreted based on numerical modeling. Improved understanding of the secular evolution of temperature and water in the mantle is a key target for future research.
DS201112-1114
2011
Johnson, T.E.White, R.W., Stevens, G., Johnson, T.E.Is the crucible reproducible? Reconciling melting experiments with thermodynamic calculations.Elements, Vol. 7, 4, August pp. 241-246.TechnologyMigmatites
DS201412-0433
2013
Johnson, T.E.Johnson, T.E., Brown, M., Klaus, J.P., VanTongeren, J.A.Delamination and recycling of Archean crust caused by gravitational instabilities.Nature Geoscience, Vol. 7, 1p.MantleArchean - craton
DS201704-0630
2017
Johnson, T.E.Johnson, T.E., Brown, M., Gardiner, N.J., Kirkland, C.L., Smithies, R.H.Earth's first stable continents did not form by subduction.Nature, Vol. 543, pp. 239-242.MantleGeodynamics

Abstract: The geodynamic environment in which Earth’s first continents formed and were stabilized remains controversial1. Most exposed continental crust that can be dated back to the Archaean eon (4 billion to 2.5 billion years ago) comprises tonalite-trondhjemite-granodiorite rocks (TTGs) that were formed through partial melting of hydrated low-magnesium basaltic rocks2; notably, these TTGs have ‘arc-like’ signatures of trace elements and thus resemble the continental crust produced in modern subduction settings3. In the East Pilbara Terrane, Western Australia, low-magnesium basalts of the Coucal Formation at the base of the Pilbara Supergroup have trace-element compositions that are consistent with these being source rocks for TTGs. These basalts may be the remnants of a thick (more than 35?kilometres thick), ancient (more than 3.5 billion years old) basaltic crust4, 5 that is predicted to have existed if Archaean mantle temperatures were much hotter than today’s6, 7, 8. Here, using phase equilibria modelling of the Coucal basalts, we confirm their suitability as TTG ‘parents’, and suggest that TTGs were produced by around 20 per cent to 30 per cent melting of the Coucal basalts along high geothermal gradients (of more than 700 degrees Celsius per gigapascal). We also analyse the trace-element composition of the Coucal basalts, and propose that these rocks were themselves derived from an earlier generation of high-magnesium basaltic rocks, suggesting that the arc-like signature in Archaean TTGs was inherited from an ancestral source lineage. This protracted, multistage process for the production and stabilization of the first continents—coupled with the high geothermal gradients—is incompatible with modern-style plate tectonics, and favours instead the formation of TTGs near the base of thick, plateau-like basaltic crust9. Thus subduction was not required to produce TTGs in the early Archaean eon.
DS201809-2046
2018
Johnson, T.E.Johnson, T.E., Gardiner, N.J., Miljkovic, K., Spencer, C.J., Kirkland, C.L., Bland, P.A., Smithies, R.H.Are Earth's oldest felsic rocks impact melts? Acasta Gneiss ComplexGoldschmidt Conference, 1p. AbstractCanada, Northwest Territoriesmeteorite

Abstract: Earth’s oldest felsic rocks, the 4.02 billion-year-old Idiwhaa gneisses of the Acasta Gneiss Complex, northwest Canada, have compositions that are distinct from the felsic rocks that typify Earth’s ancient continental nuclei, implying they formed through a different process. Using phase equilibria and trace element modelling, we show that the Idiwhaa gneisses were produced by partial melting of ironrich amphibolite host rocks at very low pressures, equating to the uppermost ~3 km of mafic crust. The heat required for such shallow melting is most easily explained through meteorite impacts. Hydrodynamic impact modelling shows that, not only is this scenario physically plausible, but the region of shallow melting appropriate to formation of the Idiwhaa gneisses would have been widespread. Given the predicted high flux of meteorites during the late Hadean, impact melting may have been the predominant mechanism that generated Hadean felsic rocks.
DS201811-2582
2018
Johnson, T.E.Johnson, T.E., Gardiner, N.J., Miljkovic, K., Spencer, C.J., Kirkland, C.L., Bland, P.A., Smithies, H.An impact melt origin for Earth's oldest known evolved rocks. Acasta GneissNature Geoscience, Vol. 11, pp. 795-799.Canada, Northwest Territoriesmelting

Abstract: Earth’s oldest evolved (felsic) rocks, the 4.02-billion-year-old Idiwhaa gneisses of the Acasta Gneiss Complex, northwest Canada, have compositions that are distinct from the felsic rocks that typify Earth’s ancient continental nuclei, implying that they formed through a different process. Using phase equilibria and trace element modelling, we show that the Idiwhaa gneisses were produced by partial melting of iron-rich hydrated basaltic rocks (amphibolites) at very low pressures, equating to the uppermost ~3?km of a Hadean crust that was dominantly mafic in composition. The heat required for partial melting at such shallow levels is most easily explained through meteorite impacts. Hydrodynamic impact modelling shows not only that this scenario is physically plausible, but also that the region of shallow partial melting appropriate to formation of the Idiwhaa gneisses would have been widespread. Given the predicted high flux of meteorites in the late Hadean, impact melting may have been the predominant mechanism that generated Hadean felsic rocks.
DS201903-0522
2019
Johnson, T.E.Johnson, T.E., Kirkland, C.L., Gardiner, C.L., Gardiner, N.J., Brown, M., Smithies, R.H., Santosh, M.Secular change in TTG compositions: implications for the evolution of Archean geodynamics.Earth and Planetary Science Letters, Vol. 505, pp. 65-75.Mantlegeothermometry

Abstract: It is estimated that around three quarters of Earth's first generation continental crust had been produced by the end of the Archaean Eon, 2.5 billion years ago. This ancient continental crust is mostly composed of variably deformed and metamorphosed magmatic rocks of the tonalite-trondhjemite-granodiorite (TTG) suite that formed by partial melting of hydrated mafic rocks. However, the geodynamic regime under which TTG magmas formed is a matter of ongoing debate. Using a filtered global geochemical dataset of 563 samples with ages ranging from the Eoarchaean to Neoarchaean (4.0-2.5 Ga), we interrogate the bulk rock major oxide and trace element composition of TTGs to assess evidence for secular change. Despite a high degree of scatter in the data, the concentrations or ratios of several key major oxides and trace elements show statistically significant trends that indicate maxima, minima and/or transitions in the interval 3.3-3.0 Ga. Importantly, a change point analysis of K2O/Na2O, Sr/Y and LaN/YbN demonstrates a statistically significant (>99% confidence) change during this 300 Ma period. These shifts may be linked to a fundamental change in geodynamic regime around the peak in upper mantle temperatures from one dominated by non-uniformitarian, deformable stagnant lid processes to another dominated by the emergence of global mobile lid or plate tectonic processes by the end of the Archaean. A notable change is also evident at 2.8-2.7 Ga that coincides with a major jump in the rate of survival of metamorphic rocks with contrasting thermal gradients, which may relate to the emergence of more potassic continental arc magmas and an increased preservation potential during collisional orogenesis. In many cases, the chemical composition of TTGs shows an increasing spread through the Archaean, reflecting the irreversible differentiation of the lithosphere.
DS201909-2046
2019
Johnson, T.E.Holder, R.M., Viete, D.R., Brown, M., Johnson, T.E.Metamorphism and the evolution of plate tectonics.Nature, doi.org/10.1038/ s41586-019-1462-2 2p.Mantleplate tectonics

Abstract: Earth’s mantle convection, which facilitates planetary heat loss, is manifested at the surface as present-day plate tectonics1. When plate tectonics emerged and how it has evolved through time are two of the most fundamental and challenging questions in Earth science1,2,3,4. Metamorphic rocks—rocks that have experienced solid-state mineral transformations due to changes in pressure (P) and temperature (T)—record periods of burial, heating, exhumation and cooling that reflect the tectonic environments in which they formed5,6. Changes in the global distribution of metamorphic (P, T) conditions in the continental crust through time might therefore reflect the secular evolution of Earth’s tectonic processes. On modern Earth, convergent plate margins are characterized by metamorphic rocks that show a bimodal distribution of apparent thermal gradients (temperature change with depth; parameterized here as metamorphic T/P) in the form of paired metamorphic belts5, which is attributed to metamorphism near (low T/P) and away from (high T/P) subduction zones5,6. Here we show that Earth’s modern plate tectonic regime has developed gradually with secular cooling of the mantle since the Neoarchaean era, 2.5 billion years ago. We evaluate the emergence of bimodal metamorphism (as a proxy for secular change in plate tectonics) using a statistical evaluation of the distributions of metamorphic T/P through time. We find that the distribution of metamorphic T/P has gradually become wider and more distinctly bimodal from the Neoarchaean era to the present day, and the average metamorphic T/P has decreased since the Palaeoproterozoic era. Our results contrast with studies that inferred an abrupt transition in tectonic style in the Neoproterozoic era (about 0.7 billion years ago1,7,8) or that suggested that modern plate tectonics has operated since the Palaeoproterozoic era (about two billion years ago9,10,11,12) at the latest.
DS201910-2245
2019
Johnson, T.E.Brown, M., Johnson, T.E.Metamorphism and evolution of subduction on Earth.American Mineralogist, Vol. 104, 8, pp. 1065-1082.Mantlesubduction

Abstract: Subduction is a component of plate tectonics, which is widely accepted as having operated in a manner similar to the present-day back through the Phanerozoic Eon. However, whether Earth always had plate tectonics or, if not, when and how a globally linked network of narrow plate boundaries emerged are matters of ongoing debate. Earth's mantle may have been as much as 200-300 °C warmer in the Mesoarchean compared to the present day, which potentially required an alternative tectonic regime during part or all of the Archean Eon. Here we use a data set of the pressure (P), temperature (T), and age of metamorphic rocks from 564 localities that vary in age from the Paleoarchean to the Cenozoic to evaluate the petrogenesis and secular change of metamorphic rocks associated with subduction and collisional orogenesis at convergent plate boundaries. Based on the thermobaric ratio (T/P), metamorphic rocks are classified into three natural groups: high T/P type (T/P > 775 °C/GPa, mean T/P ~1105 °C/GPa), intermediate T/P type (T/P between 775 and 375 °C/GPa, mean T/P ~575 °C/GPa), and low T/P type (T/P < 375 °C/GPa, mean T/P ~255 °C/GPa). With reference to published thermal models of active subduction, we show that low T/P oceanic metamorphic rocks preserving peak pressures >2.5 GPa equilibrated at P-T conditions similar to those modeled for the uppermost oceanic crust in a wide range of active subduction environments. By contrast, those that have peak pressures <2.2 GPa may require exhumation under relatively warm conditions, which may indicate subduction of young oceanic lithosphere or exhumation during the initial stages of subduction. However, low T/P oceanic metamorphic rocks with peak pressures of 2.5-2.2 GPa were exhumed from depths where, in models of active subduction, the slab and overriding plate change from being decoupled (at lower P) to coupled (at higher P), possibly suggesting a causal relationship. In relation to secular change, the widespread appearance of low T/P metamorphism in the Neoproterozoic represents a “modern” style of cold collision and deep slab breakoff, whereas rare occurrences of low T/P metamorphism in the Paleoproterozoic may reveal atypical localized regions of cold collision. Low T/P metamorphism is not known from the Archean geological record, but the absence of blueschists in particular is unlikely to reflect secular change in the composition of the oceanic crust. In addition, the premise that the formation of lawsonite requires abnormally low thermal gradients and the postulate that oceanic subduction-related rocks register significantly lower maximum pressures than do continental subduction-related rocks, and imply different mechanisms of exhumation, are not supported. The widespread appearance of intermediate T/P and high T/P metamorphism at the beginning of the Neoarchean, and the subsequent development of a clear bimodality in tectono-thermal environments are interpreted to be evidence of the stabilization of subduction during a transition to a globally linked network of narrow plate boundaries and the emergence of plate tectonics.
DS201910-2265
2019
Johnson, T.E.Holder, R., Viete, D.R., Brown, M., Johnson, T.E.Metamorphism and evolution of plate tectonics.Nature, Vol. 572, 7769, pp. 1-4.Mantleplate tectonics

Abstract: Earth’s mantle convection, which facilitates planetary heat loss, is manifested at the surface as present-day plate tectonics1. When plate tectonics emerged and how it has evolved through time are two of the most fundamental and challenging questions in Earth science1,2,3,4. Metamorphic rocks—rocks that have experienced solid-state mineral transformations due to changes in pressure (P) and temperature (T)—record periods of burial, heating, exhumation and cooling that reflect the tectonic environments in which they formed5,6. Changes in the global distribution of metamorphic (P, T) conditions in the continental crust through time might therefore reflect the secular evolution of Earth’s tectonic processes. On modern Earth, convergent plate margins are characterized by metamorphic rocks that show a bimodal distribution of apparent thermal gradients (temperature change with depth; parameterized here as metamorphic T/P) in the form of paired metamorphic belts5, which is attributed to metamorphism near (low T/P) and away from (high T/P) subduction zones5,6. Here we show that Earth’s modern plate tectonic regime has developed gradually with secular cooling of the mantle since the Neoarchaean era, 2.5 billion years ago. We evaluate the emergence of bimodal metamorphism (as a proxy for secular change in plate tectonics) using a statistical evaluation of the distributions of metamorphic T/P through time. We find that the distribution of metamorphic T/P has gradually become wider and more distinctly bimodal from the Neoarchaean era to the present day, and the average metamorphic T/P has decreased since the Palaeoproterozoic era. Our results contrast with studies that inferred an abrupt transition in tectonic style in the Neoproterozoic era (about 0.7 billion years ago1,7,8) or that suggested that modern plate tectonics has operated since the Palaeoproterozoic era (about two billion years ago9,10,11,12) at the latest.
DS202001-0040
2019
Johnson, T.E.Smithies, R.H., Lu, Y., Johnson, T.E., Kirkland, C.L., Cassidy, K.F., Champion, D.C., Mole, D.R., Zibra, I., Gessner, K., Sapkota, J., De Paoli, M.C., Poujol, M.No evidence for high pressure melting of Earth's crust in the Archean.Nature Communicatons, Vol. 10, 555912p. PdfAustraliamelting

Abstract: Much of the present-day volume of Earth’s continental crust had formed by the end of the Archean Eon, 2.5 billion years ago, through the conversion of basaltic (mafic) crust into sodic granite of tonalite, trondhjemite and granodiorite (TTG) composition. Distinctive chemical signatures in a small proportion of these rocks, the so-called high-pressure TTG, are interpreted to indicate partial melting of hydrated crust at pressures above 1.5?GPa (>50?km depth), pressures typically not reached in post-Archean continental crust. These interpretations significantly influence views on early crustal evolution and the onset of plate tectonics. Here we show that high-pressure TTG did not form through melting of crust, but through fractionation of melts derived from metasomatically enriched lithospheric mantle. Although the remaining, and dominant, group of Archean TTG did form through melting of hydrated mafic crust, there is no evidence that this occurred at depths significantly greater than the ~40?km average thickness of modern continental crust.
DS202005-0724
2020
Johnson, T.E.Brown, M., Kirkland, C.L., Johnson, T.E.Evolution of geodynamics since the Archean: significant change at the dawn of the Phanerozoic.Geology, Vol. 48, 5, pp. 488-492.Globalgeodynamics

Abstract: A time-series analysis of thermobaric ratios (temperature/pressure [T/P]) for Paleoarchean to Cenozoic metamorphic rocks identified significant shifts in mean T/P that may be related to secular change in the geodynamics on Earth. Thermobaric ratios showed significant (>95% confidence) change points at 1910, 902, 540, and 515 Ma, recording drops in mean T/P, and at 1830, 604, and 525 Ma, recording rises in mean T/P. Highest mean T/P occurred during the Mesoproterozoic, and lowest mean T/P occurred from the Cambrian to the Oligocene. Correlated changes were seen between T/P and global data sets of time-constrained hafnium (Hf) and oxygen (O) isotope compositions in zircon. The range of correlated variation in T/P, Hf, and O was larger during the formation of Rodinia than Columbia. Large changes and a wide range for these variables continued through the Phanerozoic, during which a statistically significant 83 m.y. frequency of T/P excursions recorded the high tempo of orogenic activity associated with the separation, migration, and accretion of continental terranes during the formation of Pangea. Since the early Tonian, the decreasing mean T/P of metamorphism, widespread appearance of blueschist and ultrahigh-pressure metamorphism, and wide fluctuations in Hf and O isotope compositions document a change to the modern plate-tectonic regime, characterized by widespread continental subduction and deeper slab breakoff than in the Proterozoic.
DS202102-0186
2021
Johnson, T.E.Feng, P., Wang, L., Brown, M., Johnson, T.E., Kylander-Clark, A., Piccoli, P.M.Partial melting of ultrahigh pressure eclogite by omphacite-breakdown facilitates exhumation of deeply-subducted crust.Earth and Planetary Science Letters, Vol. 554, doi.org/10.1016/ j.epsl.2020. 116664 13p. PdfMantleeclogite

Abstract: Results from numerical modelling and experimental petrology have led to the hypothesis that partial melting was important in facilitating exhumation of ultrahigh-pressure (UHP) metamorphic rocks from mantle depths. However, the melting reactions responsible are rarely well-documented from natural examples. Here we report microstructural features and compositional data that indicate in situ partial melting dominated by breakdown of omphacite in UHP eclogite from the Sulu belt, China. Diagnostic microstructures include: (i) the presence of in situ leucosome pockets composed of plagioclase, euhedral amphibole, minor K-feldspar and epidote within host zoisite- and phengite-bearing eclogite; (ii) skeletal omphacite within the leucosome pockets that has a lower jadeite content (25-45 mol.%) than rock-forming omphacite (39-54 mol.%); and, (iii) seams of Na-rich plagioclase that extend along grain boundaries separating phengite, quartz and zoisite, and which commonly exhibit low dihedral angles where they terminate at triple grain-boundary junctions. Major oxide proportions of 57 leucosome pockets, calculated using mineral modes and compositions, yield leucodiorite bulk compositions characterized by intermediate SiO2, high Al2O3 and Na2O, and low K2O contents. In primitive mantle-normalised trace element diagrams, the leucosome pockets show enrichment in large ion lithophile elements, U, Pb, Zr, Hf and Ti, but depletion in Th and Ta, patterns that are similar to those of rock-forming omphacite. Rather than forming predominantly by breakdown of phengite and/or zoisite, as widely proposed in the literature, the leucosome pockets have petrographic characteristics and major oxide and trace element compositions that are consistent with partial melting dominated by omphacite breakdown. Based on conventional thermobarometry, the eclogite was exhumed from pressure-temperature (P-T) conditions of 3.6-3.1 GPa and 900-840 °C. Partial melting led to the formation of the leucosome pockets, which equilibrated with the rims of surrounding rock-forming garnet and pyroxene during crystallisation. Conventional thermobarometry using rim compositions yields P-T conditions of 1.6-1.2 GPa and 780-690 °C, broadly consistent with calculated phase equilibria and Ti-in-zircon temperatures from zircon overgrowths. Weighted mean ages of ca 217-214 Ma from thin overgrowths on zircon are interpreted to record melt crystallisation. This study provides insight into an overlooked mechanism by which eclogites partially melt during exhumation from UHP conditions, and permits a better understanding of the processes that assist deeply-subducted continental crust to return to shallower depths.
DS202202-0194
2022
Johnson, T.E.Hartnady, M.I.H., Kirkland, C., Smithies, R.H., Johnson, T.E.Pb isotope insight into the formation of the Earth's first stable continents.Earth and planetary Science Letters, Vol. 578, 117319, 9p. PdfMantlegeochronolgy

Abstract: The formation of stable buoyant continental crust during the Archaean Eon was fundamental in establishing the planet's geochemical reservoirs. However, the processes that created Earth's first continents and the timescales over which they formed are debated. Here, we report the Pb isotope compositions of K-feldspar grains from 52 Paleoarchaean to Neoarchaean granites from the Pilbara Craton in Western Australia, one of the world's oldest and best-preserved granite-greenstone terranes. The Pb isotope composition of the Pilbara K-feldspars is variable, implying the granites were derived from crustal precursors of different age and/or variable time-integrated 238U/204Pb and 232Th/204Pb compositions. Trends to sub-mantle 207Pb/206Pb ratios preclude the influence of 4.3 Ga crustal precursors. In order to estimate crustal residence times we derive equations to calculate source model ages in a linearized Pb isotope evolution system. The best agreement between the feldspar Pb two-stage source model ages and those derived from zircon initial Hf isotope compositions requires crustal precursors that separated from a chondritic mantle source between 3.2 and 3.8 Ga, and rapidly differentiated to continental crust with 238U/204Pb and 232Th/238U ratios of ?14 and 4.2-4.5, respectively. The preservation of Pb isotope variability in the Pilbara Paleoarchaean granites indicates their early continental source rocks were preserved for up to 500 Ma after their formation. The apparent longevity of these early continental nuclei is consistent with the incipient development of buoyant melt-depleted cratonic lithosphere during the Eoarchaean to Paleoarchaean.
DS1910-0420
1914
Johnson, W.Johnson, W.The Origin of the Diamond (1914 July)South African Mining Journal, Vol. 23, PT. 2, JULY 18TH. P. 550.South AfricaGenesis
DS1993-0252
1993
Johnson, W.Christensen, R., Johnson, W., Pearson, L.M.Covariance function diagnostics for spatial linear modelsMathematical Geology, Vol. 25, No. 2, pp. 145-160GlobalGeostatistics, Kriging
DS1910-0063
1910
Johnson, W. B.Johnson, W. B.The Origin and Formation of the DiamondSouth African Journal of Science, Vol. 6, Oct. PP. 167-180.; PP. 275-286.South AfricaDiamond Genesis
DS1975-1086
1979
Johnson, W.D.JR.Johnson, W.D.JR., Haney, D.C.The Rough Creek Fault Zone, a Key to the Tectonics of the Mid-continent.Kentucky Geological Survey Symposium : Kentucky Geologic Mapping P, P. 13. (abstract.).GlobalMid-continent
DS1998-1604
1998
JohnstonWynne, P.J., Enkin, R.J., Baker, Johnston, HartThe big flush: paleomagnetic signature of a 70 Ma regional hydrothermal event in displaced rocks ....Canadian Journal of Earth Sciences, Vol. 35, No. 6, June pp. 657-71.YukonGeophysics - paleomagnetics, Northern Cordillera
DS1985-0309
1985
Johnston, A.Johnston, A.,Andnava, S.J.Recurrence Rates and Probability Estimates for the New Madrid Seismic Zone.Journal of Geophysical Research, Vol. 90, No. B5, JULY 10TH. PP. 6737-6753.United States, Central States, Gulf Coast, Arkansas, Missouri, TennesseeMidcontinent, Mississippi Embayment, Tectonics
DS1992-0799
1992
Johnston, A.Johnston, A.New Madrid: the rift, the river and the earthquakeEarth, Vol. 1, No. 1, pp. 34-43MissouriTectonics, Rifting -midcontinent
DS1990-0774
1990
Johnston, A.C.Johnston, A.C., Kanter, L.R.Earthquakes in stable continental crustScientific American, Vol. 262, No. 3, March pp. 68-82MissouriCrust, Earthquakes
DS1992-0800
1992
Johnston, A.C.Johnston, A.C.The rift, the river and the earthquake. the story of the New Madrid faultzoneEarth, Vol. 1, No. 1, January pp. 34-43Missouri, Appalachia, MidcontinentTectonics -rifting, Popular account
DS1994-1583
1994
Johnston, A.C.Shedlock, K.M., Johnston, A.C.Investigations of the New Madrid Seismic Zone; disc. crustal stress @prelim. study Crowley's Ridge.United States Geological Survey (USGS) Prof. Paper, No. 1538 A-C, 45p.ArkansasGeophysics -seismics, New Madrid Seismic Zone, Crowley's Ridge
DS1985-0310
1985
Johnston, A.D.Johnston, A.D., Stout, J.H., Murthy, V.R.Geochemistry and Origin of Some Unusually Oxidized Alkaline rocks from Kaluai, Hawaii.Journal of VOLCANOLOGY, Vol. 25, No. 3-4, JULY PP. 225-248.United States, HawaiiGeochemistry
DS1989-1661
1989
Johnston, A.D.Wyllie, P.J., Carroll, M.R., Johnston, A.D., Rutter, M.J., SekineInteraction among magmas and rocks in subduction zone regions-experimental studies from slab to mantle to crustEuropean Journal of Mineralogy, Vol. 1, No. 2, pp. 165-180GlobalMantle, Experimental petrology
DS1997-0851
1997
Johnston, A.D.Nixon, G.T., Johnston, A.D., Martin, R.F.Nature and origin of primitive magmas at subduction zonesCanadian Mineralogist, Vol. 35, No. 2, AprilPhilippines, Mexico, British Columbia, NewfoundlandBook - table of contents, Magmas, subduction zones
DS2001-0920
2001
Johnston, A.D.Pickering-Witter, J., Johnston, A.D.The effects of variable bulk composition on the melting systematics of fertile peridotitic assemblages.Contributions to Mineralogy and Petrology, Vol. 140, No. 2, pp. 190-211.GlobalMineral chemistry, Peridotites
DS2001-1041
2001
Johnston, A.D.Schwab, B.E., Johnston, A.D.Melting systematics of modally variable, compositionally intermediate peridotites and effectsJournal of Petrology, Vol. 42, No. 10, Oct. pp. 1789-1812.GlobalMineralogy - mineral fertility
DS200512-0484
2004
Johnston, A.D.Johnston, A.D., Schwab, B.E.Constraints on clinopyroxene/ melt partitioning of REE, Rb, Sr, Ti, Cr, Zr. Nb during mantle melting:insights from direct peridotite melting experiments 1.0 GPaGeochimica et Cosmochimica Acta, Vol. 68, 23, pp. 4949-4962.MantleMelting
DS201112-1105
2011
Johnston, A.D.Weaver, S.L., Wallace, P.J., Johnston, A.D.A comparative study of continental vs. intraoceanic arc mantle melting: experimentally determined phase relations of hydrous primitive melts.Earth and Planetary Science Letters, Vol. 308, 1-2, pp. 97-106.MantleMelting
DS1988-0760
1988
Johnston, C.R.Williams, P.R., Johnston, C.R., Almond, R.A., Simamora, W.H.Late Cretaceous to early Tertiary structural elements of West KalimantanTectonophysics, Vol. 148, No. 3/4, May 1, pp. 279-298GlobalBlank
DS1989-0720
1989
Johnston, D.H.Johnston, D.H.Recent advances in exploitation geophysicsThe Leading Edge, Vol. 8, No. 9, September pp. 22-28GlobalGeophysics, Petroleum overview
DS1995-0889
1995
Johnston, J.Johnston, J., Wannamaker, P.Deep electrical resistivity structure of the eastern Great Basin and Colorado Plateau Interior: implicationsEos, Vol. 76, No. 46, Nov. 7. p.F604. Abstract.Colorado PlateauMantle -extension, Geophysics -seismics
DS1970-0727
1973
Johnston, J.L.Johnston, J.L.Petrology and Geochemistry of Ultramafic Xenoliths from The jagersfontein Mines, Orange Free State, South Africa.1st International Kimberlite Conference, EXTENDED ABSTRACT VOLUME, PP. 181-183.South AfricaPetrology, Geochemistry
DS1997-1225
1997
Johnston, J.M.Wannamaker, P.E., Doermer, W.M., Johnston, J.M.Subdued state of tectonism of Great Basin interior relative to margin Based on deep resistivity structureEarth and Planetary Science Letters, Vol. 150, No. 1-2, July pp. 41-102.GlobalTectonics, Geophysics - seismics
DS1997-1226
1997
Johnston, J.M.Wannamaker, P.E., Johnston, J.M., Stodt, J.A., Booker, J.R.Anatomy of the southern Cordilleran hingeline, Utah and Nevada, from deep electric resistivity profilingGeophysics, Vol. 62, No. 4, July-Aug., pp. 1069-86Utah, Nevada, Basin and RangeGeophysics, Tectonics
DS201610-1840
2016
Johnston, P.Aravanis, T., Chen, J., Fuechsle, M., Grujic, M., Johnston, P., Kok, Y., Magaraggia, R., Mann, A., Mann, L., McIntoshm S., Rheinberger, G., Saxey, D., Smalley, M., van Kann, F., Walker, G., Winterflood, J.VK1 tm - a next generation airborne gravity gradiometer.ASEG-PESA-AIG 2016 25th Geophysical Conference, Abstract 5p.TechnologyGradiometer

Abstract: The minerals exploration industry’s demand for a highly precise airborne gravity gradiometer has driven development of the VK1TM Airborne Gravity Gradiometer, a collaborative effort by Rio Tinto and the University of Western Australia. VK1TM aims to provide gravity gradient data with lower uncertainty and higher spatial resolution than current commercial systems. In the recent years of VK1TM development, there have been significant improvements in hardware, signal processing and data processing which have combined to result in a complete AGG system that is approaching competitive survey-ready status. This paper focuses on recent improvements. Milestone-achieving data from recent lab-based and moving-platform trials will be presented and discussed, along with details of some advanced data processing techniques that are required to make the most use of the data.
DS1910-0169
1911
Johnston, R.A.A.Camsell, C.C., Johnston, R.A.A.British Columbia Diamonds and PlatinumMining Engineering WORLD., Vol. 35, SEPT. 30TH. PP. 647-648.Canada, British ColumbiaBlank
DS1910-0288
1912
Johnston, R.A.A.Johnston, R.A.A.Section on MineralogyGeological Survey of Canada SUMMARY Report FOR 1911, PP. 262-263.Canada, British ColumbiaBlank
DS1910-0289
1912
Johnston, R.A.A.Johnston, R.A.A.Mineralogical Notes. DiamondsGeological Survey of Canada SUMMARY Report FOR 1911, P. 360.Canada, Quebec, British ColumbiaBlank
DS1910-0290
1912
Johnston, R.A.A.Johnston, R.A.A.Reported Discussion of Diamonds in Ungava DistrictLetter To G.f. Kunz, APRIL 15TH.Canada, Quebec, Labrador, James Bay LowlandsBlank
DS1910-0465
1915
Johnston, R.A.A.Johnston, R.A.A.A List of Canadian Mineral OccurrencesGeological Survey of Canada MEMOIR., No. 74, GEOL. SERIES No. 61, 275P. P. 86.Canada, British ColumbiaBlank
DS1950-0478
1959
Johnston, R.H.Johnston, R.H.The Geology of the Northern Leucite Hills, Sweetwater County,wyoming.Msc. Thesis, University Wyoming, 83P.United States, Wyoming, Rocky Mountains, Leucite HillsLamproite
DS1995-0890
1995
Johnston, S.T.Johnston, S.T., Erdmer, P.Hot side up aureole in southwest Yukon and limits on terrane assembly Of the northern Canadian CordilleraGeology, Vol. 23, No. 5, May pp. 419-422Yukon, British Columbia, AlaskaNisling Terrane, metamorphism
DS1997-0562
1997
Johnston, S.T.Johnston, S.T., Thorkelson, D.J.Cocos-Nazca slab window beneath Central AmericaEarth and Planetary Science Letters, Vol. 146, No. 3/4, Feb. 1, pp. 465-474GlobalSubduction, Slab window
DS2000-0450
2000
Johnston, S.T.Johnston, S.T.The Cape Fold Belt and syntaxis and the rotated Falkland Islands: dextral transpressional tectonics ..Journal of African Earth Sciences, Vol.31, No.1, July, pp.51-63.GondwanaRifting, hot spots, orogeny, Cape Fold Belt
DS2001-0541
2001
Johnston, S.T.Johnston, S.T.The Great Alaskan Terrane Wreck: reconciliation of paleomagnetic and geological dat a northern CordilleraEarth and Planetary Science Letters, Vol. 193, No. 3-4, pp.273-85.Alaska, YukonGeophysics - paleomagnetics, Geological belts, orogeny
DS2003-0204
2003
Johnston, S.T.Canil, D., Johnston, S.T., Evers, K., Shellnutt, J.G., Creaser, R.A.Mantle exhumation in an early Paleozoic passive margin, northern Cordillera, YukonJournal of Geology, Vol. 1111, pp. 313-327.YukonPeridotite, Mantle lithosphere
DS2003-0205
2003
Johnston, S.T.Canil, D., Johnston, S.T., Evers, K., Shellnutt, J.G., Creaser, R.A.Mantle exhumation in an Early Paleozoic passive margin, northern Cordillera, YukonJournal of Geology, Vol. 111, 3, pp. 313-28.YukonTectonics
DS2003-0383
2003
Johnston, S.T.English, J.M., Johnston, S.T., Wang, K.Thermal modelling of the Laramide Orogeny: testing the flat slab subduction hypothesisEarth and Planetary Science Letters, Vol. 214, 3-4, pp.619-32.Colorado, WyomingSubduction, geothermometry
DS2003-0985
2003
Johnston, S.T.Murphy, J.B., Hynes, A.J., Johnston, S.T., Keppie, J.D.Reconstructing the ancestral Yellowstone plume from accreted seamounts and itsTectonophysics, Vol. 365, 1-4, pp.185-194.United StatesSubduction, Hotspot
DS200412-0265
2003
Johnston, S.T.Canil, D., Johnston, S.T., Evers, K., Shellnutt, J.G., Creaser, R.A.Mantle exhumation in an Early Paleozoic passive margin, northern Cordillera, Yukon.Journal of Geology, Vol. 111, 3, pp. 313-28.Canada, YukonTectonics
DS200412-0520
2004
Johnston, S.T.English, J.M., Johnston, S.T.The Laramide Orogeny: what were the driving forces?International Geology Review, Vol.46, 9, Sept. pp. 833-838.United States, WyomingTectonics
DS200412-0521
2003
Johnston, S.T.English, J.M., Johnston, S.T., Wang, K.Thermal modelling of the Laramide Orogeny: testing the flat slab subduction hypothesis.Earth and Planetary Science Letters, Vol. 214, 3-4, pp.619-32.United States, Colorado, WyomingSubduction, geothermometry
DS200412-1382
2003
Johnston, S.T.Murphy, J.B., Hynes, A.J., Johnston, S.T., Keppie, J.D.Reconstructing the ancestral Yellowstone plume from accreted seamounts and its relationship to flat slab subduction.Tectonophysics, Vol. 365, 1-4, pp.185-194.United StatesSubduction Hotspot
DS200512-0263
2005
Johnston, S.T.English, J.M., Johnston, S.T.Collisional orogenesis in the northern Canadian Cordillera: implications for Cordilleran crustal structure, ophiolite emplacement, continental growth, and the terrane hypothesis.Earth and Planetary Science Letters, Vol. 232, 3-4, April 15, pp. 333-344.Canada, British Columbia, YukonTectonics, Stikine Terrane, accretion
DS200512-0668
2005
Johnston, S.T.MacKenzie, J.M., Canil, D., Johnston, S.T., English, J., Mihalynuk, M.G., Grant, B.First evidence for ultrahigh pressure garnet peridotite in the North American Cordillera.Geology, Vol. 33, 2, pp. 105-108.Canada, Yukon, British ColumbiaUHP, Mantle lithosphere
DS200612-0217
2006
Johnston, S.T.Canil, D., Johnston, S.T., Mihalynuk, M.Mantle redox in Cordilleran ophiolites as a record of oxygen fugacity during partial melting and the life time of mantle lithosphere.Earth and Planetary Science Letters, Vol. 248, 1-2, Aug. 15, pp. 91-102.MantleRedox
DS200612-0218
2005
Johnston, S.T.Canil, D., Mihalynuk, M., MacKenzie, J.M., Johnston, S.T., Grant, B.Diamond in the Atlin-Nakin a region, British Columbia: insights from heavy minerals in stream sediments.Canadian Journal of Earth Sciences, Vol. 42, 12, Dec. pp. 2161-2171.Canada, British Columbia, Yukon, United States, AlaskaGeochemistry
DS200812-0526
2008
Johnston, S.T.Johnston, S.T.The Cordilleran ribbon continent of North America.Annual Review of Earth and Planetary Sciences, Vol. 36, May, pp. 495-530.United States, CanadaTectonics
DS201012-0485
2010
Johnston, S.T.McLeish, D.F., Kressall, R., Crozier, J., Johnston, S.T., Chakhmouradian, A., Mortensen, J.K.The Aley carbonatite complex - part 1 structural evolution of a Cordilleran niobium deposit mine.International Workshop Geology of Rare Metals, held Nov9-10, Victoria BC, Open file 2010-10, extended abstract pp. 21-24.Canada, British ColumbiaCarbonatite
DS201905-1019
2019
Johnston, S.T.Canil, D., Grundy, R., Johnston, S.T.Thermal history of the Donjek harzburgite massif in ophiolite from Yukon, Canada with implications for the cooling of oceanic mantle lithosphere.Lithos, Vol. 328-329, pp. 33-42.Canada, Yukongeothermometry

Abstract: We examine the partial melting and the cooling history of a ~5?km section of mantle lithosphere preserved in the Donjek massif, part of a Permian ophiolite in the northern Cordillera of Yukon, Canada. The mantle rocks are depleted spinel harzburgite containing <3% clinopyroxene displaying steep rare-earth element (REE) chondrite-normalized profiles and low (Gd/Yb)n (0.02 to 0.07) compared to most other ophiolites. The REE patterns of clinopyroxene can be modeled as 16-20% partial melts of typical depleted mid-ocean ridge (MOR) mantle. The REE exchange between coexisting ortho- and clinopyroxene preserves temperatures (TREE) of 1150-1360?°C, some of the highest values recorded in ophiolites and abyssal peridotites, and show a positive correlation with CaMg exchange (solvus) temperatures (TBKN) of 900-970?°C. The harzburgite represents lithosphere formed at an initial melting temperature of ~ 1350?°C that cooled at rate of 10?1 to 10?4?°C/year as deduced by TREE values with cation diffusion and grain size data. The TREE temperatures and cooling rates for the Donjek massif show a regular systematic variation with depth from the crust-mantle transition along a trend similar to the Samail ophiolite of Oman, consistent with conductive heat transfer beneath a cool lower crust. High near-solidus temperatures and the cooling rates in the massif were a consequence of rapid obduction against oceanic crust along either a transform or low angle detachment soon after melt extraction. Final emplacement of the ophiolite as klippen on underlying continental crust occurred ~ 40?m.y. later.
DS201906-1365
2019
Johnston, S.T.Zhang, W., Johnston, S.T., Currie, C.A.Kimberlite magmatism induced by west-dipping subduction of the North American plate.Geology, Vol. 47, pp. 395-398.United States, Canadasubduction

Abstract: Kimberlite magmas are volatile-rich, potassic, and ultramafic, and they are host to most of the world’s diamond deposits. A continental-scale kimberlite magmatic belt (the central Cretaceous kimberlite corridor [CCKC]) is found in the interior of the North American continent. Parallel to and coeval with the CCKC, the Cretaceous Omineca magmatic belt (OMB) is located in the Cordilleran orogen. Cordilleran magmatism, including the OMB, is commonly explained through long-lived east-dipping subduction beneath the western margin of the continent. However, this does not explain the temporal and spatial relationships between the OMB and CCKC. We suggest that west-dipping subduction of North American lithosphere beneath the eastern side of the Cordillera explains both. In this model, subduction resulted in arc magmatism of the OMB. The contemporaneous CCKC was formed by extensional stress acting on the continent as it flexed upon entry into the trench. Using a semi-infinite elastic beam model, we show that flexure of a subducting continental plate (elastic thickness = 120 km) produces tensile stresses in the deep continental lithosphere, coincident with the location of the CCKC.
DS201908-1792
2019
Johnston, S.T.McLeish, D.F., Johnston, S.T.The Upper Devonian Aley carbonatite, NE British Columbia: a product of Antler orogenesis in the western Foreland belt of the Canadian Cordillera.Journal of the Geological Society, Vol. 176, 4, pp. 620-628.Canada, British Columbiacarbonatite

Abstract: Paleozoic continental margin strata in the western Foreland Belt of the Canadian Cordillera are characterized in part by alkaline volcanic sequences, carbonatite intrusions, coarse clastic sedimentary units, and erosional unconformities. These strata also contain a record of mid-Paleozoic contractional deformation unseen in coeval passive margin strata in the eastern Foreland Belt. In order to test potential genetic links between Paleozoic alkaline igneous activity, active margin sedimentation, and deformation in the western Foreland Belt, and better understand their implications for the evolution of the Foreland Belt as a whole, we have undertaken a detailed mapping and structural study of the Aley carbonatite intrusion and its host strata in the western Foreland Belt of NE British Columbia. Our work demonstrates that carbonatite emplacement was coeval with a Late Devonian contractional nappe-forming tectonic event. Interpreting tectonism as associated with continental collision along a long-lived active margin provides the best explanation for our structural and stratigraphic observations, and suggests that the western Foreland Belt is far-travelled and exotic relative to coeval passive margin strata in the eastern Foreland Belt. Deformed alkaline-carbonatite intrusions that characterize continental suture zones in Africa may provide an analogue for the Aley carbonatite and correlative alkaline-carbonatite complexes in the western Foreland Belt.
DS1982-0300
1982
Johnston, W.H.Johnston, W.H., Cra exploration pty. ltd.El 2354 Attack Creek, Final Report 1980-1982Northern Territory Geological Survey Open File Report, No. CR 82/385, 4P.Australia, Northern TerritoryProspecting, Sampling, Geophysics, Geochemistry, Landsat
DS1993-0443
1993
Johnstone, D.Finlayson, D.M., Owen, A., Johnstone, D., Wake-Dyster, K.D.Moho and petrologic crust-mantle bounday coincide under southeasternAustraliaGeology, Vol. 21, No. 8, August pp. 707-710AustraliaMantle, Petrology
DS201212-0409
2010
Johnstone, I.Linton, T., Paul, A., Johnstone, I.,Hunter, K.DiamondNite tester.The Australian Gemmologist, Vol. 24, 4, Oct-Dec pp.TechnologyDiamond tester
DS1992-0801
1992
Johnstone, R.M.Johnstone, R.M.Geology and mineral potential of the Camsell Lake areaNorthwest Territories, Preprint from PDA., 2pNorthwest TerritoriesSulphides, Brief overview
DS1999-0631
1999
Jokat, W.Schlindwein, V., Jokat, W.Structure and evolution of the continental crust of northern Greenland and integrated geophysical studies.Journal of Geophysical Research, Vol. 104, No. 7, July 10, pp. 15227-46.GreenlandTectonics, Geophysics - seismics
DS2003-0663
2003
Jokat, W.Jokat, W., Boebel, T., Konig, M., Meyer, U.Timing and geometry of early Gondwana breakupJournal of Geophysical Research, Vol. 108, B9, Sept. 16, 10.1029/2002JB001802RodiniaTectonics
DS200412-0922
2003
Jokat, W.Jokat, W., Boebel, T., Konig, M., Meyer, U.Timing and geometry of early Gondwana breakup.Journal of Geophysical Research, Vol. 108, B9, Sept. 16, 10.1029/2002 JB001802Gondwana, RodiniaTectonics
DS200512-0712
2005
Jokat, W.Mechita, C., Schmidt-Aursch, C., Jokat, W.The crustal structure of central East Greenland- I. From the Caledonian orogen to the Tertiary igneous province.Geophysical Journal International, Vol. 160, 2, pp. 736-752.Europe, GreenlandTectonics - not specific to diamonds
DS200512-0713
2005
Jokat, W.Mechita, C., Schmidt-Aursch, C., Jokat, W.The crustal structure of central East Greenland- II. From the Precambrian Shield to the recent mid-oceanic ridges.Geophysical Journal International, Vol. 160, 2, pp. 753-760.Europe, GreenlandTectonics - not specific to diamonds
DS201212-0711
2012
Jokat, W.Suckro, S.K., Gohl, K., Funck, T., Heyde, I., Ehrardt, A., Schreckenberger, B., Gerlings, J., Damm, V., Jokat, W.The crustal structure of southern Baffin Bay: implications from a seismic refraction experiment.Geophysical Journal International, Vol. 190, 1, pp. 37-58.Canada, Nunavut, Baffin Island, Europe, GreenlandGeophysics - seismics
DS201509-0425
2015
Jokat, W.Ryberg, T., Haberland, C., Haberlau, T., Weber, M.H., Klaus, B., Behrmann, J.H., Jokat, W.Crustal structure of northwest Namibia: evidence for plume rift continent interaction.Geology, Vol. 43, 8,pp. 739-Africa, NamibiaPlume, rifting

Abstract: The causes for the formation of large igneous provinces and hotspot trails are still a matter of considerable dispute. Seismic tomography and other studies suggest that hot mantle material rising from the core-mantle boundary (CMB) might play a significant role in the formation of such hotspot trails. An important area to verify this concept is the South Atlantic region, with hotspot trails that spatially coincide with one of the largest low-velocity regions at the CMB, the African large low shear-wave velocity province. The Walvis Ridge started to form during the separation of the South American and African continents at ca. 130 Ma as a consequence of Gondwana breakup. Here, we present the first deep-seismic sounding images of the crustal structure from the landfall area of the Walvis Ridge at the Namibian coast to constrain processes of plume-lithosphere interaction and the formation of continental flood basalts (Paraná and Etendeka continental flood basalts) and associated intrusive rocks. Our study identified a narrow region (<100 km) of high-seismic-velocity anomalies in the middle and lower crust, which we interpret as a massive mafic intrusion into the northern Namibian continental crust. Seismic crustal reflection imaging shows a flat Moho as well as reflectors connecting the high-velocity body with shallow crustal structures that we speculate to mark potential feeder channels of the Etendeka continental flood basalt. We suggest that the observed massive but localized mafic intrusion into the lower crust results from similar-sized variations in the lithosphere (i.e., lithosphere thickness or preexisting structures).
DS1999-0338
1999
Jokinen, J.Jokinen, J., Kukkonen, I.T.Random modelling of the lithospheric thermal regime: forward simulations applied to uncertainty analysis.Tectonophysics, Vol. 306, No. 3-4, June 20, pp. 277-92.GlobalGeothermometry, Lithosphere
DS1999-0339
1999
Jokinen, J.Jokinen, J., Kukkonen, I.T.Inverse simulation of the lithospheric thermal regime using the Monte Carlomethod.Tectonophysics, Vol. 306, No. 3-4, June 20, pp. 293-310.GlobalGeothermometry, Lithosphere
DS201803-0446
2017
Jokn, M.J.Engi, M., Lanari, P., Jokn, M.J.Significant ages - an introduction to petrochronology.Reviews in Mineralogy & Geochemistry, Vol. 83, Chap. 1, pp. 1-12.Technologygeochronology

Abstract: Question: Why "Petrochronology"? Why add another term to an already cluttered scientific lexicon? Answer: Because petrologists and geochronologists need a term that describes the unique, distinctive way in which they apply geochronology to the study of igneous and metamorphic processes. Other terms just won’t do.
DS202203-0349
2022
Jokubauskas, P.Grabarczyk, A., Gil, G., Liu, Y., Kotowski, J., Jokubauskas, P., Barnes, J.D., Nejbert, K., Wisniewska, J., Baginski, B.Ultramafic-alkaline-carbonatite Tajno intrusion in NE Poland: a new hypothesis.Ore Geology Reviews, doi.org/10.1016/j.oregeorev.2022.104772 Europe, Polandcarbonatite

Abstract: This manuscript presents results of the newest petrographic, mineralogical and bulk chemical, as well as H, C and O stable isotope study of carbonatites and associated silicate rocks from the Tajno Massif (NE Poland). The Tajno Intrusion is a Tournaisian-Visean ultramafic-alkaline-carbonatite body emplaced within the Paleoproterozoic rocks of the East European Craton (EEC). Carbonatites of the Tajno Massif can be subdivided into the calciocarbonatite (calcite), ferrocarbonatite (ankerite), and breccias with an ankerite-fluorite matrix. Due to location at the cratonic margin and abundance in the REE, Tajno classifies (Hou et al., 2015) as the carbonatite-associated REE deposit (CARD), and more precisely as the Dalucao-Style orebody (the breccia-hosted orebody). High Fe2O3 (13.8 wt%), MnO (2.1 wt%), total REE (6582 ppm), Sr (43895 ppm), Ba (6426 ppm), F (greater than10000 ppm) and CO2 contents points for the involvement of the slab - including pelagic metalliferous sediments - in the carbonatites formation. Spatial relations and Sr isotope composition ((87Sr/86Sr)i = 0.7043-0.7048; Wiszniewska et al., 2020) of alkali clinopyroxenite and syenite suggest that these are products of differentiation of the magma, generated by the initial melting of the SCLM due to influx of F-rich fluids from subducted marine sediments. Carbonatites Sr isotope composition ((87Sr/86Sr)i = 0.7037-0.7038), and Ba/Th (16-20620) and Nb/Y (0.01-6.25) ratios, link their origin with a more advanced melting of the SCLM, triggered by CO2-rich fluids from the subducted AOC and melts from sediments. The Tajno Massif - and coeval mafic-alkaline intrusions - age, high potassic composition, and location along the craton margin nearly parallel the Variscan deformation front, are suggesting Variscan subduction beneath the EEC. The oxygen isotope compositions of clinopyroxene (?18O value = 5.2‰) and alkali feldspar (?18O value = 5.7‰), from alkali clinopyroxenite and foid syenite, respectively, are consistent with mantle-derived magmas. Isotopic compositions of carbonatites and breccias (carbonate ?18O = 8.7‰ to 10.7‰; ?13C = -4.8‰ to ?0.4‰) span from values of primary carbonatites to carbonatites affected by a fractionation or sedimentary contamination. The highest values (?18O = 10.7‰; ?13C = -0.4‰) were reported for breccia cut by numerous veins confirming post-magmatic hydrothermal alteration. The lowest carbonate ?18O (9.3‰ to 10.7‰) and ?13C (?5.0‰ to ?3.8‰) values are reported for veins in alkali clinopyroxenites, whereas the highest ?18O (11.2‰) and ?13C (?1.2‰ to ?1.1‰) values are for veins in syenites and trachytes. Isotopic composition of veins suggests hydrothermal origin, and interaction with host mantle-derived rocks, as well as country rocks. In silicate rocks of the Tajno Massif, fluid influx leads to the development of Pb, Zn, Cu, Ag, Au sulfide mineralization-bearing stockwork vein system, with carbonate, silicate and fluorite infilling the veins. Bulk-rock contents of molybdenum (925 ppm), rhenium (905 ppb) and palladium (29 ppb) are notable. The Re-rich molybdenite association with galena, pyrite and Th-rich bastnäsite in carbonate veins is similar as in Mo deposits associated with carbonatites, implying the mantle source of Mo and Re.
DS200412-0208
2003
Jol, H.M.Bristow, C.S., Jol, H.M.Ground penetrating radar in sediments.Geological Society of London , SP 211, 338p. approx. $ 135.USTechnologyBook - GPR
DS2003-0160
2003
Jol., H.M.Bristow, C.S., Jol., H.M.Ground penetrating radar in sedimentsGeological Society of London Publ., http://bookshop.geolsoc.org.uk, SP 211, 338p. approx. $ 135.USGlobalBook - GPR - general interest
DS200412-0662
2004
Joliff, B.L.Giesting, P.A., Hofmeister, A.M., Wopenka, B., Gwanmesia, G.D., Joliff, B.L.Thermal conductivity and thermodynamics of majoritic garnets: implications for the transition zone.Earth and Planetary Science Letters, Vol. 218, 1-2, Jan. 30, pp. 45-56.MantleGeothermometry, heat capacity, entropy
DS1997-0563
1997
Jolis, J.Jolis, J.Marketing rough diamonds outside the CSOPreprint, from International Conference held June 1997., 8p.GlobalDiamond markets, Trans Hex Group
DS1994-0850
1994
Jolis, J.F.Jolis, J.F.Marketing rough diamonds outside of De BeersThe Canadian Institute of Mining, Metallurgy and Petroleum (CIM) District 6, Oct. 11-15th. Vancouver, pp. 57-62.GlobalMarketing, CSO, alternative
DS1994-0851
1994
Jolis, J.F.Jolis, J.F.Alternative diamond marketingThe Canadian Institute of Mining, Metallurgy and Petroleum (CIM) Section Meeting Oct. 12, Vancouver, List of speakersGlobalUpdate, Marketing
DS2001-0151
2001
Jolivet, L.Burov, E., Jolivet, L., LePourhiet, L., Poliakov, A.A thermomechanical model of exhumation of high pressure HP and ultra high pressure UHP metamorphic rocks...Tectonophysics, Vol. 342, No. 2, pp. 113-36.GlobalAlpine type collision belts, UHP
DS2001-0542
2001
Jolivet, L.Jolivet, L., Nataf, H.C.Geodynamics and rheology of the lithosphere along the DSS profile SVEKA in the central Scandinavian Shield.Balkema Publishing, 236p. approx. $ 90.00GlobalBook - ad, Tectonics, plate boundaries
DS2003-0096
2003
Jolivet, L.Bellashen, N., Faccenna, C., Funiciello, F., Daniel, J.M., Jolivet, L.Why did Arabia separate from Africa? Insights from 3-D laboratory experimentsEarth and Planetary Science Letters, Vol. 216, 3, pp. 365-81.AfricaTectonics, rifting
DS200412-0131
2003
Jolivet, L.Bellashen, N., Faccenna, C., Funiciello, F., Daniel, J.M., Jolivet, L.Why did Arabia separate from Africa? Insights from 3-D laboratory experiments.Earth and Planetary Science Letters, Vol. 216, 3, pp. 365-81.AfricaTectonics, rifting
DS200412-0574
2004
Jolivet, L.Fournier, M., Jolivet, L., Davy, P., Thomas, J-C.Backarc extension and collision: an experimental approach to the tectonics of Asia.Geophysical Journal International, Vol. 157, 2, pp. 871-889.AsiaTectonics
DS200512-0485
2005
Jolivet, L.Jolivet, L., Raimbourg, H., Labrousse, L., Avigad, D., Leroy, Y., Austrheim, H., Andersen, T.B.Softening triggered by eclogitization, the first step toward exhumation during continental subduction.Earth and Planetary Science Letters, Vol. 237, 3-4, Sept. 15, pp. 532-547.Europe, NorwayEclogite, subduction
DS200612-0386
2005
Jolivet, L.Famin, V., Herbert, R., Philippot, P., Jolivet, L.Ion probe and fluid inclusions evidence for co-seismic fluid infiltration in a crustal detachment.Contributions to Mineralogy and Petrology, Vol. 150, 3, pp. 354-367.MantleGeochronology
DS200712-0865
2006
Jolivet, L.Raimbourg, H., Jolivet, L., Leroy, Y.Consequences of progressive eclogization on crustal exhumation, a mechanical study.Geophysical Journal International, Vol. 168, 1, pp. 379-401.TechnologyEclogite
DS201212-0595
2012
Jolivet, L.Rolland, Y., Lardeaux, J-M, Jolivet, L.Deciphering orogenic evolution.Journal of Geodynamics, Vol. 56-57, pp. 1-6.MantleTectonics
DS201212-0596
2012
Jolivet, L.Rolland, Y., Lardeaux, J-M., Jolivet, L.Deciphering orogenic evolution.Journal of Geodynamics, Vol. 56-57, pp. 1-6.MantleSubduction
DS201312-0257
2013
Jolivet, L.Faccenna, C., Becker, T.W., Jolivet, L., Keskin, M.Mantle convection in the Middle East: reconciling Afar upwelling, Arabia indentation and Aegean trench rollback.Earth and Planetary Science Letters, Vol. 375, pp. 254-269.Asia, ArabiaConvection
DS201801-0008
2018
Jolivet, L.Clerc, C., Ringenbach, J-C., Jolivet, L., Ballard, J-F.Rifted margins: ductile deformation, boudinage, continentward-dipping normal faults and the role of the weak crust.Gondwana Research, Vol. 53, 1, pp. 20-40.Mantlerifting

Abstract: The stunningly increased resolution of the deep crustal levels in recent industrial seismic profiles acquired along most of the world's rifted margins leads to the unraveling of an unexpected variety of structures. It provides unprecedented access to the processes occurring in the middle and lower continental crust. We present a series of so far unreleased profiles that allows the identification of various rift-related geological processes such as crustal boudinage, ductile shear and low-angle detachment faulting, and a rifting history that differs from the classical models of oceanward-dipping normal faults. The lower crust in rifted margins appears much more intensely deformed than usually represented. At the foot of both magma-rich and magma-poor margins, we observe clear indications of ductile deformation of the deep continental crust along large-scale shallow dipping shear zones. These shear zones generally show a top-to-the-continent sense of shear consistent with the activity of Continentward Dipping Normal Faults (CDNF) observed in the upper crust. This pattern is responsible for a migration of the deformation and associated sedimentation and/or volcanic activity toward the ocean. We discuss the origin of these CDNF and investigate their implications and the effect of sediment thermal blanketing on crustal rheology. In some cases, low-angle shear zones define an anastomosed pattern that delineates boudin-like structures. The maximum deformation is localized in the inter-boudin areas. The upper crust is intensely boudinaged and the highly deformed lower crust fills the inter-boudins underneath. The boudinage pattern controls the position and dip of upper crustal normal faults. We present some of the most striking examples from the margins of Uruguay, West Africa, South China Sea and Barents Sea, and discuss their implications for the time-temperature history of the margins.
DS201905-1051
2019
Jolivet, L.Koptev, A., Beniest, A., Gerya, T., Ehlers, T.A., Jolivet, L., Leroy, S.Plume induced breakup of a subducting plate: microcontinent formation without cessation of the subduction process.Geophysical Research Letters, Vol. 46, 7, pp. 3663-3675.Mantlesubduction

Abstract: Separation of microcontinental blocks from their parent continent is usually attributed to abrupt relocation of concentrated extension from the mid?oceanic ridge to the adjacent continental margin. In the context of extensional passive margin evolution, previous extensive numerical and analog studies have revealed that hot upwelling mantle flow plays a key role in the mechanical weakening of the passive margin lithosphere needed to initiate a ridge jump. This, in turn, results in continental breakup and subsequent microcontinent isolation. However, the consequences of mantle plume impingement on the base of a moving lithospheric plate that is already involved into subduction are still unexplored quantitatively. Here we present the results of 3?D thermo?mechanical models showing that even in the context of induced plate motion (contractional boundary conditions), which are necessary to sustain continuous convergence, thermal and buoyancy effects of the mantle plume emplaced at the bottom of the continental part of the subducting plate are sufficient to initiate continental breakup and the subsequent opening of a new oceanic basin that separates the microcontinental block from the main body of the continent. With these models, we show that it is physically possible to form microcontinents in a convergent setting without the cessation of subduction.
DS201710-2223
2017
Jolivet, M.Danelian, T., Jolivet, M., Ionov, D.Insights into the geology and paleontology of Siberia from French-Siberian collaboration in the Earth Sciences.Bulletin de la Societe Geologique de France *eng, Vol. 188, 1-2, 7p.Russia, Siberiadeposit - Udachnaya
DS201712-2696
2018
Jollands, M.C.Jollands, M.C., Hanger, B.J., Yaxley, G.M., Hermann, J., Kilburn, M.R.Timescales between mantle metasomatism and kimberlite ascent indicated by diffusion profiles in garnet crystals from periodotite xenoliths.Earth and Planetary Science Letters, Vol. 481, pp. 143-153.Africa, South Africadeposit - Wesselton

Abstract: Rare garnet crystals from a peridotite xenolith from the Wesselton kimberlite, South Africa, have distinct zones related to two separate episodes of mantle metasomatism. The garnet cores were firstly depleted through melt extraction, then equilibrated during metasomatism by a potentially diamond-forming carbonate-bearing or proto-kimberlitic fluid at 1100-1300?°C and 4.5-5.5 GPa. The garnet rim chemistry, in contrast, is consistent with later overgrowth in equilibrium with a kimberlite at around and . This suggests that the rock was physically moved upwards by up to tens of kilometres between the two metasomatic episodes. Preserved high Ca, Al and Cr contents in orthopyroxenes suggest this uplift was tectonic, rather than magmatic. Diffusion profiles were measured over the transitions between garnet cores and rims using electron microprobe (Mg, Ca, Fe for modelling, plus Cr, Mn, Ti, Na, Al) and nano Secondary Ion Mass Spectrometry (NanoSIMS; 89Y, along with 23Na, Ca, Cr, Fe, Mn and Ti) analyses. The short profile lengths (generally <10 ?m) and low Y concentrations (0.2-60 ppm) make the NanoSIMS approach preferable. Diffusion profiles at the interface between the zones yield constraints on the timescale between the second metasomatic event and eruption of the kimberlite magma that brought the xenolith to the surface. The time taken to form the diffusion profiles is on the order of 25 days to 400 yr, primarily based on modelling of Y diffusion along with Ca, Fe and Mg (multicomponent diffusion) profiles. These timescales are too long to be produced by the interaction of the mantle xenolith with the host kimberlite magma during a single-stage ascent to the crust (hours to days). The samples offer a rare opportunity to study metasomatic processes associated with failed eruption attempts in the cratonic lithosphere.
DS201808-1755
2018
Jollands, M.C.Jollands, M.C., Hanger, B.J., Yaxley, G.M., Hermann, J., Kilburn, M.R.Timescales between mantle metasomatism and kimberlite ascent indicated by diffusion profiles in garnet crystals from peridotite xenoliths.Earth and Planetary Science Letters, Vol. 481, 1, pp. 143-153.Mantlekimberlite

Abstract: Rare garnet crystals from a peridotite xenolith from the Wesselton kimberlite, South Africa, have distinct zones related to two separate episodes of mantle metasomatism. The garnet cores were firstly depleted through melt extraction, then equilibrated during metasomatism by a potentially diamond-forming carbonate-bearing or proto-kimberlitic fluid at 1100-1300?°C and 4.5-5.5 GPa. The garnet rim chemistry, in contrast, is consistent with later overgrowth in equilibrium with a kimberlite at around and . This suggests that the rock was physically moved upwards by up to tens of kilometres between the two metasomatic episodes. Preserved high Ca, Al and Cr contents in orthopyroxenes suggest this uplift was tectonic, rather than magmatic. Diffusion profiles were measured over the transitions between garnet cores and rims using electron microprobe (Mg, Ca, Fe for modelling, plus Cr, Mn, Ti, Na, Al) and nano Secondary Ion Mass Spectrometry (NanoSIMS; 89Y, along with 23Na, Ca, Cr, Fe, Mn and Ti) analyses. The short profile lengths (generally <10 ?m) and low Y concentrations (0.2-60 ppm) make the NanoSIMS approach preferable. Diffusion profiles at the interface between the zones yield constraints on the timescale between the second metasomatic event and eruption of the kimberlite magma that brought the xenolith to the surface. The time taken to form the diffusion profiles is on the order of 25 days to 400 yr, primarily based on modelling of Y diffusion along with Ca, Fe and Mg (multicomponent diffusion) profiles. These timescales are too long to be produced by the interaction of the mantle xenolith with the host kimberlite magma during a single-stage ascent to the crust (hours to days). The samples offer a rare opportunity to study metasomatic processes associated with failed eruption attempts in the cratonic lithosphere.
DS1996-0670
1996
Jolley, A.Islam, S.M.N., Jolley, A.Sustainable development in Asia: the current state and policy decisionsNatural Resources forum, Vol. 20, No. 4, pp. 263-279AsiaEconomics, Legal, environment
DS2002-0786
2002
Jolley, D.W.Jolley, D.W., Bell, B.R.The North Atlantic Igneous Province: stratigraphy, tectonic, volcanic and magmatic processes.Geological Society of London (U.K.), 344p.$ 142.00 http://bookshop.geolsoc.org.ukNorway, GreenlandBook - igneous and sedimentary processes
DS2002-0787
2002
Jolley, D.W.Jolley, D.W., Bell, B.R.The North Atlantic Igneous Province: stratigraphy, tectonic, volcanic and magmatic processes.Geological Society of London Special Paper, No. 197, 344p.$ 200. www.geosoc.orgNorway, Greenland, DenmarkBook
DS1992-0802
1992
Jolly, A.D.Jolly, A.D., Sheriff, S.D.Paleomagnetic study of thrust sheet motion along the Rocky Mountain frontin MontanaGeological Society of America (GSA) Bulletin, Vol. 104, No. 6, June pp. 779-785MontanaPaleomagnetics, Tectonics
DS1970-0728
1973
Jolly, J.H.Jolly, J.H.The Mineral Industry for the Territory of Southwest AfricaUnited States Bureau of Mines AREA REPORTS, Vol. 3, PP. 771-778. ALSO 1974 PP. 817-824.Southwest Africa, NamibiaDiamonds, Industry
DS1960-0558
1965
Jolly, J.L.Heyl, A.V., Brock, M., Jolly, J.L., Wells, G.E.Regional Structure of Southeast Missouri and Illinois- Kentucky Mineral District.United States Geological Survey (USGS) Bulletin., No. 1202-B, 20P.United States, Kentucky, Missouri, Illinois, Central StatesBlank
DS1960-0559
1965
Jolly, J.L.Heyl, A.V., Brock, M.R., Jolly, J.L., Wells, C.E.Regional Structure of the Southeast Missouri and Illinois Kentucky Mineral Districts.United States Geological Survey (USGS) Bulletin., No. 1202-B, 20P.GlobalMid Continent
DS1986-0362
1986
Jolly, J.L.Heyl, A.V., Brock, M.R., Jolly, J.L.Phanerozoic igneous rocks, including kimberlites of the United States craton west of the Blue Ridge Mountains and east of the Rocky Mountains and their associated7th. IAGOD Symposium abstract volume, Held August 18-22, Lulea Sweden, pp. 407-408. (abstract.)Colorado, New Mexico, Wyoming, Montana, South DakotaBlank
DS1988-0303
1988
Jolly, J.L.Heyl, A.V., Brock, M.R., Jolly, J.L.Phanerozoic igneous rocks, including kimberlites of the United States craton west of the Blue Ridge Mtns. &east of the Rocky Mountains and their Association mineral deposI.a.g.o.d., Proceedings Of The Seventh Quadrennial Iagod Symposium, Vol. 7, pp. 103-110Arkansas, Tennessee, Kentucky, Illinois, Appalachia, MidcontinentMontana, South Dakota, Colorado, Wyoming, Tectonics
DS1991-0805
1991
Jolly, W.T.Jolly, W.T., Lidiak, E.G.Origin of Puerto Rican Mesozoic shoshonites: evidence from incompatible lithophile element geochemistryGeological Society of America Annual Meeting Abstract Volume, Vol. 23, No. 5, San Diego, p. A 442GlobalShoshonite, Geochemistry
DS1991-0806
1991
Jonah, S.E.Jonah, S.E., Ansah, K.Debt funding for African mining Projects: issues, options and sourcesInstitute of Mining and Metallurgy (IMM) Newsletter, December pp. 13-19Ghana, Africa, South AfricaEconomics, Mining projects
DS200412-1513
2004
JonassonPeate, D.W., Baker, J.A., Breddam, K., Waight, T.E., Skovgaard, A.C., Stecher, O., Prestvik, T., JonassonPb isotope heterogeneity of the mantle beneath Iceland.Geochimica et Cosmochimica Acta, 13th Goldschmidt Conference held Copenhagen Denmark, Vol. 68, 11 Supp. July, ABSTRACT p.A569.Europe, IcelandGeochronology
DS201510-1796
2015
Jonathan, C.Ostrye, S., Jonathan, C., Tozer, R., Dirlam, D.M.The GIA Library's digitization project: providing access in a digital world.GSA Annual Meeting, Paper 300-2, 1p. Abstract only BoothTechnologyGIA library

Abstract: Through its digitization project, the Gemological Institute of America’s (GIA) Richard T. Liddicoat Library is making available digital copies of historic and unique books to geoscientists worldwide. By the end of 2015, more than 100 volumes from the library’s rare book collection, including the gemology and mineralogy library collected by John and Marjorie Sinkankas, will be posted online in a readily accessible, searchable format. In December 2014, the library purchased the BC100 Book Capture system by Digital Transitions. This equipment includes two Phase One digital camera backs with Schneider Kreuznach lenses, which photograph the two pages of an open book simultaneously. Images are captured at a minimum resolution of 300 pixels per inch, with higher resolutions used for books that are small, have highly detailed color images, or have small or faded text. Capture One imaging software is used to generate a TIFF image for each page. These TIFF files will be saved indefinitely as preservation masters, from which derivative files can be created and modified for future use. Then docWorks post-processing software by Content Conversion Specialists is used to perform optical character recognition (OCR) and generate a searchable PDF and ePub output for each book. The OCR supports a variety of languages including those using European and Cyrillic alphabets, as well as Chinese, Japanese, and Korean characters. A number of GIA’s digital books are now available online to view and download for free through Internet Archive (https://archive.org/details/@gia_library) with new books being uploaded every few days. Available books include out-of-copyright titles dating from 1496 to the 1920s. One of the oldest digitized books, Libellus de Lapidibus Preciosis (Book of Precious Stones) by Marbode, Bishop of Rennes, printed in 1511, was originally written in the 11th century and discusses properties of 60 gems. Another title, René Just Haüy’s influential Traité de Minéralogie (Treatise of Mineralogy) published in 1801, describes the laws governing crystal structure and was the first rational system for identifying and classifying minerals. The digitization project is ongoing with plans to ultimately post hundreds of volumes related to gems and minerals.
DS200612-1130
2006
Jonckheere, R.Ratschbacher, L., Franz, L., Enkelmann, E., Jonckheere, R., Porschke, A., Hacker, B.R., Dong, S., Zhang, Y.The Sino-Korean Yangtze suture, the Huwan detachment and the Paleozoic Tertiary exhumation of ultra high pressure rocks along the Tongbai Xinxian Dabie Mtns.Geological Society of America, Special Paper, No. 403, pp. 45-76.ChinaUHP
DS1989-0558
1989
JonesGupta, J.C., Jones, Kerr, Krentz, et al.Elecromagnetic sounding and crustal electrical conductivity in the region of the Wopmay Orogen.Canadian Journal of Earth Sciences, Vol. 26, pp. 2385-95.Northwest TerritoriesGeophysics - magnetics, Tectonics
DS1995-0673
1995
JonesGreen, R.W.E., Smith, C.B., Jones, Muller, ViljoenProgress towards understanding the Kaapvaal lithosphere geophysical and geochemical perspectives.Proceedings of the Sixth International Kimberlite Conference Extended Abstracts, p. 188-90.South AfricaGeophysics, Craton -Kaapvaal
DS1998-0136
1998
JonesBoerner, D.E., Craven, J.A., Kurtz, R.D., Ross, JonesThe Great Falls Tectonic Zone: suture or intracontinnental shear zone?Canadian Journal of Earth Sciences, Vol. 35, No. 2, Feb. pp. 175-183.Alberta, WyomingTectonics, Archean, Proterozoic, Geophysics - electromagnetic
DS1998-0137
1998
JonesBoerner, D.E., Kurtz, R.D., Craven, J.A., Ross, JonesGeophysical evidence of mantle involvement in Paleoproterzoic orogenesisAnnales Geophysicae, 23rd Meet abstracts 16. supp. p. 175.AlbertaGeophysics
DS2000-0094
2000
JonesBoerner, D.E., Kurtz, R.D., Craven, J.A., Ross, JonesA synthesis of electromagnetic studies in lithoprobe Alberta Basement Transect: constraints PaleoproterozoicCanadian Journal of Earth Sciences, Vol.37, no11, Nov.pp.1509-34.AlbertaTectonics - indentation, Geophysics - electromagnetics
DS2000-0256
2000
JonesEaton, D.W., Atkinson, Ferguson, Adams, Asudeh, JonesPOLARIS: an in depth look at Canada's subcontinental mantle and earthquakehazards.Geological Association of Canada (GAC)/Mineralogical Association of Canada (MAC) 2000 Conference, 4p. abstract.Ontario, Northwest TerritoriesGeophysics - seismics, lithospheric, Structure - Phanerozoic
DS2001-0286
2001
JonesEaton, D., Ferguson, Jones, Hope, WuA geophysical shear sense indicator and the role of mantle lithosphere in transcurrent faulting.Slave-Kaapvaal Workshop, Sept. Ottawa, 3p. abstractNorthwest TerritoriesGeophysics, Great Slave Lake Shear Zone
DS2001-0306
2001
JonesEvans, R.L., Chave, Jones, FillouxDeep bottom magnetotelluric sounding in the Slave CratonSlave-Kaapvaal Workshop, Sept. Ottawa, 1p. abstractNorthwest TerritoriesGeophysics - magnetics, tellurics
DS2002-0956
2002
JonesLitvin, Y.A., Jones, BeardCrystallization of diamond syngenetic minerals in melts of Diamondiferous carbonatites of Chagatai Massif 7.GPaDoklady, Vol. 381A, No. 9, pp. 1066-9.Russia, UzbekistanCarbonatite, Geochronology
DS200912-0522
2009
JonesMuller, M.R., Jones, Evans, Grutter, Hatton, Garcia, Hamilton, Miensopust, Cole, Ngwisanyi, Hutchins, Fourie, Jelsma,Aravanis.Pettit, Webb, WasborgLithospheric structure, evolution and diamond prospectivity of the Rehoboth Terrane and western Kaapvaal Craton, southern Africa: constraints from broadbandLithos, In press - available 57p..Africa, South Africa, BotswanaGeophysics - broadband magnetotellurics
DS200412-2003
2004
Jones, A.Tomlinson, E., Jones, A., Milledge, J.High pressure experimental growth of diamond using C K2CO3-KCl as an analogue for Cl bearing carbonate fluid.Lithos, Vol. 77, 1-4, Sept. pp. 287-294.TechnologyDiamond growth, potassium carbonate, potassium chloride
DS200612-0362
2006
Jones, A.Eaton, D.W., Jones, A.Tectonic fabric of the subcontinental lithosphere: evidence from seismic magnetotelluric and mechanical anisotropy.Physics of the Earth and Planetary Interiors, Vol. 158, 2-4, pp. 85-91.MantleGeophysics - seismics
DS200712-0282
2006
Jones, A.Eaton, D.W., Jones, A.Tectonic fabric of the subcontinental lithosphere: evidence from seismic magnetotelluric and mechanical anistropy.Physics of the Earth and Planetary Interiors, Vol. 158, 2-4, Oct. 16, pp. 85-91.MantleGeophysics - seismics
DS201012-0329
2010
Jones, A.Jones, A.Carbon rich melts in the deep mantle.Goldschmidt 2010 abstracts, AbstractMantleMelting
DS201012-0496
2010
Jones, A.Mikhail, S., Dobosi, G., Verchovsky, S., Jones, A., Kurat, G.Organic looking carbon and nitrogen isotope compositions in mantle derived diamondites: mantle fractionation vs reworked crustal organics?International Mineralogical Association meeting August Budapest, abstract p. 185.Africa, southern AfricaDiamondites
DS201312-0443
2013
Jones, A.Jones, A.Carbon & conductive properties of the mantle.GEM Diamond Workshop Feb. 21-22, Noted onlyMantleGeophysics
DS201312-0444
2013
Jones, A.Jones, A.Integrated petrological modelling of MT, seismics, gravity, heat flow, topography and geoid on the Kaapvaal Craton.AEM-SAGA Conference, Talk title listedAfrica, South AfricaGeophysics
DS201312-0445
2013
Jones, A.Jones, A.Water in cratonic mantle deduced from velocity and electrical conductivity.AEM-SAGA Conference, Talk title listedMantleGeophysics
DS201412-0040
2014
Jones, A.Basu, S., Jones, A.Helium 3 stored in mantle diamond periodically mobilised by deep carbonate melts?Goldschmidt Conference 2014, 1p. AbstractMantleMelting
DS201607-1355
2016
Jones, A.Jones, A.Illuminating craton architecture using deep-probing electromagnetic studies.IGC 35th., Session A Dynamic Earth 1p. AbstractMantleGeophysics
DS201607-1356
2016
Jones, A.Jones, A.Imaging the lithosphere-asthenosphere boundary beneath continents using mineral physics and surface observational constraints.IGC 35th., Session The Deep Earth 1 p. abstractMantleGeophysics
DS201705-0838
2017
Jones, A.Jones, A., Alvaro, M., McMillan, P., Price, D., Milledge, J.Lonsdaleite signatures and shock remnants in mantle diamond?European Geosciences Union General Assembly 2017, Vienna April 23-28, 1p. 16597 AbstractChinaDeposit - Liaoning
DS201709-2006
2017
Jones, A.Jones, A., Wood, B., Mikhail, S.Oldest diamond crystallisation on Earth: a metal driven Hadean growth model related to core formation.Goldschmidt Conference, abstract 1p.Mantlediamond genesis

Abstract: When hot liquid metal drained towards the core during and shortly after Earth accretion, exceptional conditions may have led to the first global crystallisation of diamond. Newly reported metallic iron trapped in large mantle diamond invites comparison between commercial Fe-Ni-Co “HPHT” diamond growth and natural environments. We evaluate possible conditions for Hadean diamond crystallisation from liquid ironrich metal where thermal and compositional gradients influence diamond crystallization. The solubility of up to 6% carbon has little effect on the phase transitions of the metallic iron phase diagram and carbon generally decreases with increasing pressure in solid iron based on calculated enthalpies. Models for core differentiation provide two scenarios (i) from an accumulated metal “pond” (ii) from massive downward mobile metal diapirs. A refinement arises from a parameterization of self-propagating downward fractures filled by turbulent liquid iron as proposed by Stephenson to send a transponder to the core; negatively buoyant diamond crystals would float. Experiments show that diamond growth under these conditions is fast (~1 carat per hour) and micro-textures of natural diamond with metallic inclusions retain substantial isotopic heterogeneities. We speculate that if the oldest diamond trapped metallic iron on its way to form the core, such “stranded core” might be recognized by trace element compositions, and could retain anomalous isotopic signatures of W and Hf.
DS1993-0755
1993
Jones, A.E.Jones, A.E.Electromagnetic images of modern and ancient subduction zones #1Tectonophysics, Vol. 219, pp. 29-47.MantleSubduction, Geophysics -magnetics
DS1988-0333
1988
Jones, A.G.Jones, A.G.A magnetotelluric investigation under the Williston Basin of southeastern Saskatchewan #1Canadian Journal of Earth Sciences, Vol. 25, pp. 1132-39.SaskatchewanGeophysics - magnetotellurics
DS1989-0721
1989
Jones, A.G.Jones, A.G., Boerner, D.E., Kurtz, R.D.Electrical crustal structure at the edge of the North American cratonGeological Association of Canada (GAC) Annual Meeting Program Abstracts, Vol. 14, p. A104. (abstract.)OntarioTectonics, Kapuskasing Lithoprobe
DS1990-0775
1990
Jones, A.G.Jones, A.G., Craven J.A.The North American Central Plains conductivity anomaly and its correlationPhysics of the Earth and Planetary Interiors, Vol. 60, pp. 169-194SaskatchewanGeophysics, North American Central Plains anomaly
DS1990-1064
1990
Jones, A.G.Morel-a-l'hussier, P., Green, A. G., Jones, A.G., Latham, T.The crust beneath the intracratonic Williston Basin from geophysical datain: Pinet, B., Bois, C. editors The potential of deep seismic profiling for, pp. 141-160SaskatchewanGeophysics, Williston Basin
DS1991-1332
1991
Jones, A.G.Percival, J.A., Shaw, D.M., Milkereit, B., White, D.J., Jones, A.G.A closer look at deep crustal reflectionsEos, Vol. 72, No. 32, August 6, pp. 337, 339, 340, 341United States, CanadaTectonics, Geophysics -seismics
DS1992-0803
1992
Jones, A.G.Jones, A.G., Gough, D.I., Kurtz, R.D., De Laurier, J.M., et al.Electromagnetic images of regional structure in the southern CanadianCordilleraGeophysical Research Letters, Vol. 12, No. 24, pp. 2373-2376Cordillera, British ColumbiaGeophysics -electromagnetic, Tectonics, structure
DS1993-0756
1993
Jones, A.G.Jones, A.G.Electromagnetic images of modern and ancient subduction zones #2Tectonophysics, Vol. 220, pp. 29-45MantleGeophysics -electromagnetics, Subduction
DS1993-0757
1993
Jones, A.G.Jones, A.G.Electromagnetic images of modern and ancient subduction zones #1Tectonophysics, Vol. 219, pp. 29-45MantleGeophysics -seismics, Subduction
DS1993-0758
1993
Jones, A.G.Jones, A.G., Craven, J.A., et al.North American central plains conductivity anomaly with the Trans-Hudson Orogen in northern Saskatchewan, CanadaGeology, Vol. 21, No. 11, November pp. 1027-1030SaskatchewanGeophysics -seismics, Trans-Hudson orogen
DS1993-0759
1993
Jones, A.G.Jones, A.G., Craven, J.A., McNeice, G.W., Ferguson, I.J., Boyce, T.North American Central Plains conductivity anomaly within the Trans-Hudson Orogen in northern Saskatchewan, Canada.Geology, Vol. 21, No. 11, November pp. 1027-1030.SaskatchewanGeophysics -magnetics, Tectonics
DS1996-0695
1996
Jones, A.G.Jones, A.G., Eaton, D.W., White, D., Bostock, M., MareschalGeophysical measurements for lithospheric parametersGeological Survey of Canada, LeCheminant ed, OF 3228, pp. 243-250.Canada, mantleGeophysics -seismics, Lithosphere
DS1996-0696
1996
Jones, A.G.Jones, A.G., Ferguson, I.J., et al.Electrical characteristics of the Slave lithosphere and adjaceent terranes:possible implications for earth.Northwest Territories Exploration Overview, Nov. 26, p. 3-20 - 3-21.Northwest TerritoriesLithoprobe Program, Anton Terrane
DS2000-0255
2000
Jones, A.G.Eaton, D.W., Asudeh, I., Jones, A.G.Constraints on mantle strain from seismic and electrical anisotropy: Great Slave Lake shear zone northwest Territories.Geological Association of Canada (GAC)/Mineralogical Association of Canada (MAC) 2000 Conference, 7p. abstract.Northwest TerritoriesGeophysics - seismics, Mantle deformation
DS2000-0451
2000
Jones, A.G.Jones, A.G.Electromagnetic images of the earth from near surface to deep within the mantle.Geological Association of Canada (GAC)/Mineralogical Association of Canada (MAC) 2000 Conference, 4p. abstract.MantleGeophysics - magnetotellurics, Tomography
DS2000-0452
2000
Jones, A.G.Jones, A.G.The electric lithosphere of the Slave CratonGeological Society of America (GSA) Abstracts, Vol. 32, No. 7, p.A-165.Northwest TerritoriesTectonics, Craton - Slave
DS2000-0453
2000
Jones, A.G.Jones, A.G., Evans, R., Chave, A.Electrifying images of the Slave Craton. #2Geological Association of Canada (GAC)/Mineralogical Association of Canada (MAC) Calgary May 2000, 7p.Northwest TerritoriesGeophysics - magnetotelluric, conductivity, Lithosphere - modeling, Diavik, Contwoyto
DS2000-0454
2000
Jones, A.G.Jones, A.G., Evans, R., Chave, A.Electrifying images of the Slave Craton. #1Geological Association of Canada (GAC)/Mineralogical Association of Canada (MAC) 2000 Conference, 7p. abstract.Northwest TerritoriesGeophysics - reflection profiles, electomagnetics, Deposit - Ekati, Diavik, Jericho, Kennady
DS2000-0455
2000
Jones, A.G.Jones, A.G., Snyder, D., Asudeh, I., White, D., EatonLithospheric architecture at the Rae Hearne boundary revealed through magnetotelluric and seismic experimentGeological Association of Canada (GAC)/Mineralogical Association of Canada (MAC) 2000 Conference, 6p. abstract.Northwest Territories, Churchill, AlbertaGeophysics - seismics, magnetotellurics, Crustal - boundary
DS2000-0559
2000
Jones, A.G.Ledo, J., Jones, A.G., Ferguson, I.J.Preliminary interpretations and implications for tectonics and deep geology of the Northern Cordillera..Geological Association of Canada (GAC)/Mineralogical Association of Canada (MAC) 2000 Conference, 4p. abstract.Northwest Territories, Yukon, AlbertaGeophysics - Magnetotellurics, Lithoprobe - SNORCLE.
DS2001-0217
2001
Jones, A.G.Craven, J.A., Jones, A.G.Comparisons of Slave and Superior electric lithosphereSlave-Kaapvaal Workshop, Sept. Ottawa, 3p. abstractNorthwest Territories, Ontario, Manitoba, AlbertaGeophysics - magnetics, Craton
DS2001-0543
2001
Jones, A.G.Jones, A.G.Information about the continental mantle from deep electromagnetic studiesProspectors and Developers Association of Canada (PDAC) Short Course, KEGS diamond workshop, 37p.Canada, Fennoscandia, Finland, Norway, Northwest TerritoriesGeophysics - seismics, Technology - techniques, methodology, electromagnetic, magnetotellur
DS2001-0544
2001
Jones, A.G.Jones, A.G., Craven, J.A.Carbon in the mantle? the electromagnetic responses of the Slave and Superior cratons compared and contrasted.29th. Yellowknife Geoscience Forum, Nov. 21-23, abstract p. 39-40.Mantle, Northwest Territories, OntarioGeophysics - carbon based conductors
DS2001-0545
2001
Jones, A.G.Jones, A.G., Ferguson, Chave, Evans, SprattSlave electromagnetic studiesSlave-Kaapvaal Workshop, Sept. Ottawa, 2p. abstractNorthwest TerritoriesGeophysics - electromagnetic
DS2001-0546
2001
Jones, A.G.Jones, A.G., Ferguson, I.J., Chave, Evans, McNeiceElectric lithosphere of the Slave CratonGeology, Vol. 29, No. 5, May, pp. 423-6.Northwest TerritoriesGeophysics - magnetotelluric, electromagnetic, Plate tectonics, kimberlite pipes
DS2001-0547
2001
Jones, A.G.Jones, A.G., Snyder, D., Ford, K.L., Spratt, J., EvansGeophysical experiments in central Baffin Island29th. Yellowknife Geoscience Forum, Nov. 21-23, abstract p. 38-9.Northwest Territories, Baffin IslandGeophysics, Trans Hudson Orogen
DS2001-0668
2001
Jones, A.G.Ledo, J., Jones, A.G.Regional electrical resistivity structure of the southern Canadian Cordillera and its physical interpretJournal of Geophysical Research, Vol. 106, No. 12, pp. 30,755-70.Cordillera, British Columbia, AlbertaGeophysics
DS2001-0764
2001
Jones, A.g.McNeice, G.W., Jones, A.g.Multisite, multifrequency tensor decomposition of magnetotelluric dataGeophysics, Vol. 66, No. 1, Jan. pp. 159-72.MantleGeophysics - magnetotellurics
DS2001-1095
2001
Jones, A.G.Snyder, D.B., Berman, R., Jones, A.G., Asudeh, I.Tectonic model for the unroofing of the northeastern Hearne domain based on geophysical petrological....29th. Yellowknife Geoscience Forum, Nov. 21-23, abstract p. 79.Northwest Territories, Saskatchewan, AlbertaTectonics
DS2002-0788
2002
Jones, A.G.Jones, A.G., Snyder, D., Hanmer, S., Asudeh, I., White, D., Eaton, D., Clarke, G.Magnetotelluric and teleseismic study across the Snowbird Tectonics Zone of theGeophysical Research Letters, Vol. 29, 17, 10.1029/2002GL015359Manitoba, Saskatchewan, AlbertaGeophysics - MT, seismics
DS2002-1742
2002
Jones, A.G.Wu, C., Ferguson, I.J., Jones, A.G.Magnetotelluric response and geoelectric structure of the Great Slave Lake shear zoneEarth and Planetary Science Letters, Vol.196, 1-2, Feb.28, pp.35-50.Northwest TerritoriesGeophysics - tellurics, Tectonics
DS2003-0320
2003
Jones, A.G.Davis, W.J., Jones, A.G., Bleeker, W., Grutter, H.Lithosphere development in the Slave Craton: a linked crustal and mantle perspectiveLithos, Vol. 71, 2-4, pp. 575-589.Northwest Territories, NunavutTectonics
DS2003-0664
2003
Jones, A.G.Jones, A.G.Deep probing electromagnetic studies for area selection of possible diamond provincesGeological Association of Canada Annual Meeting, Abstract onlyNorthwest TerritoriesGeophysics
DS2003-0665
2003
Jones, A.G.Jones, A.G., Craven, J.A.Area selection for diamond exploration using deep probing electromagnetic surveying8 Ikc Www.venuewest.com/8ikc/program.htm, Session 5, AbstractGlobalTarget area selection, Geophysics - MIT
DS2003-0666
2003
Jones, A.G.Jones, A.G., Ledo, J., Ferguson, I.J.Lithospheric electrical structure of northwestern CanadaGeological Association of Canada Annual Meeting, Abstract onlyNorthwest TerritoriesGeophysics - seismics, Lithoprobe
DS2003-0667
2003
Jones, A.G.Jones, A.G., Lezaeta, P., Ferguson, I.J., Chave, A.D., Evans, R.L., Garcia, X.The electrical structure of the Slave CratonLithos, Vol. 71, 2-4, pp. 505-527.Northwest Territories, NunavutGeophysics - seismics
DS2003-0781
2003
Jones, A.G.Ledo, J., Jones, A.G., Craven, J.A.Electrical parameter maps of Canada8 Ikc Www.venuewest.com/8ikc/program.htm, Session 9, POSTER abstractCanada, Northwest TerritoriesGeophysics
DS200412-0384
2004
Jones, A.G.Craven, J.A., Ferguson, I.J., Jones, A.G., Skulski, T.Roots of the Slave and Superior Provinces observed with deep looking magnetotellurics.Geological Association of Canada Abstract Volume, May 12-14, SS14-07 p. 266.abstractCanada, Northwest TerritoriesCraton, geophysics - seismics, mineralogy
DS200412-0421
2003
Jones, A.G.Davis, W.J., Jones, A.G., Bleeker, W., Grutter, H.Lithosphere development in the Slave Craton: a linked crustal and mantle perspective.Lithos, Vol. 71, 2-4, pp. 575-589.Canada, NunavutTectonics
DS200412-0923
2003
Jones, A.G.Jones, A.G.Deep probing electromagnetic studies for area selection of possible diamond provinces.Geological Association of Canada Annual Meeting, Abstract onlyCanada, Northwest TerritoriesGeophysics
DS200412-0924
2003
Jones, A.G.Jones, A.G., Craven, J.A.Area selection for diamond exploration using deep probing electromagnetic surveying.8 IKC Program, Session 5, AbstractTechnologyTarget area selection Geophysics - MIT
DS200412-0925
2004
Jones, A.G.Jones, A.G., Craven, J.A.Area selection for diamond exploration using deep probing electromagnetic surveying.Lithos, Vol. 77, 1-4, Sept. pp. 765-782.Canada, Northwest TerritoriesSlave Craton, Superior Craton, Rae Craton, magnetotellu
DS200412-0926
2003
Jones, A.G.Jones, A.G., Ledo, J., Ferguson, I.J.Lithospheric electrical structure of northwestern Canada.Geological Association of Canada Annual Meeting, Abstract onlyCanada, Northwest TerritoriesGeophysics - seismics Lithoprobe
DS200412-0927
2003
Jones, A.G.Jones, A.G., Lezaeta, P., Ferguson, I.J., Chave, A.D., Evans, R.L., Garcia, X., Spratt, J.The electrical structure of the Slave Craton.Lithos, Vol. 71, 2-4, pp. 505-527.Canada, NunavutGeophysics - seismics
DS200412-1097
2003
Jones, A.G.Ledo, J., Jones, A.G., Craven, J.A.Electrical parameter maps of Canada.8 IKC Program, Session 9, POSTER abstractCanada, Northwest TerritoriesCraton studies Geophysics
DS200412-1098
2004
Jones, A.G.Ledo, J., Jones, A.G., Ferguson, I.J., Wolynec, L.Lithospheric structure of the Yukon, northern Canadian Cordillera, obtained from magnetotelluric data.Journal of Geophysical Research, Vol. 109, B10, April 30, 10.1029/2003JB002516Canada, YukonGeophysics - magnetotelluric
DS200412-2023
2004
Jones, A.G.Unsworth, M., Wenbo, W., Jones, A.G., Li, S., Bedrosian, P., Booker, J., Sheng, J., Ming, D., Handong, T.Crustal and upper mantle structure of northern Tibet imaged with magnetotelluric data.Journal of Geophysical Research, Vol. 109, B2, Feb. 13, 10.1029/2002 JB002305Asia, TibetTectonics, geophysics - seismics
DS200512-0273
2005
Jones, A.G.Evans, S., Jones, A.G., Spratt, J., Katsube, J.Central Baffin Island electromagnetic experiment (CBEX): mapping the North American central plains (NACP) conductivity anomaly in the Canadian arctic.Physics of the Earth and Planetary Interiors, Vol. 150, 1-3, May 16, pp. 107-122.Canada, Nunavut, Baffin IslandTrans Hudson Orogeny, geophysics - magnetotelluric
DS200512-0285
2005
Jones, A.G.Ferguson, I.J., Stevens, K.M., Jones, A.G.Electrical resistivity imaging of the central Trans-Hudson orogen.Canadian Journal of Earth Sciences, Vol. 42, 4, April pp. 495-515.Canada, Northwest TerritoriesGeophysics
DS200512-0316
2005
Jones, A.G.Garcia, X., Jones, A.G.Electromagnetic image of the Trans Hudson Orogen - THO94 transect.Canadian Journal of Earth Sciences, Vol. 42, 4, April pp. 479-483.Canada, Saskatchewan, ManitobaGeophysics - Lithoprobe
DS200512-0486
2005
Jones, A.G.Jones, A.G., Ledo, J., Ferguson, I.J.Electromagnetic images of the Trans-Hudson orogen: the North American Central Plains anomaly revealed.Canadian Journal of Earth Sciences, Vol. 42, 4, April pp. 457-478.Canada, Northwest TerritoriesGeophysics - EM
DS200512-0609
2005
Jones, A.G.Ledo, J., Jones, A.G.Upper mantle temperature determined from combining mineral composition, electrical conductivity laboratory studies and magnetotelluric field observations:Earth and Planetary Science Letters, Vol. 236, 1-2, pp. 258-268.Canada, British Columbia, Alberta, Yukon, CordilleraGeophysics, geochemistry
DS200512-0610
2005
Jones, A.G.Ledo, J., Jones, A.G.Upper mantle temperature determined from combining mineral composition, electrical conductivity laboratory studies and magnetotelluric field observations.Earth and Planetary Science Letters, Advanced in press,Canada, British Columbia, YukonIntermontane belt, Cordillera, geophysics
DS200512-1034
2005
Jones, A.G.Spratt, J.E., Jones, A.G., Nelson, K.D., Unsworth, M.J., INDEPTH MT TeamCrustal structure of the India - Asia collision zone, southern Tibet, from INDEPTH MT investigations.Physics of the Earth and Planetary Interiors, India, Asia, TibetGeophysics, EM and magnetotelluric
DS200512-1175
2005
Jones, A.G.White, D.J., Thomas, M.D., Jones, A.G., Hope, J., Nemeth, B., Hajnal, Z.Geophysical transect across a Paleoproterozoic continent-continent collision zone: the Trans-Hudson Orogen.Canadian Journal of Earth Sciences, Vol. 42, 4, April pp. 385-402.Canada, Northwest TerritoriesGeophysics - seismics
DS200512-1200
2005
Jones, A.G.Wu, X., Ferguson, I.J., Jones, A.G.Geoelectric structure of the Proterozoic Wopmay Orogen and adjacent terranes, Northwest Territories, Canada.Canadian Journal of Earth Sciences, Vol. 42, 6, June pp. 955-981.Canada, Northwest TerritoriesGeophysics - magnetotellurics, subduction
DS200612-0524
2006
Jones, A.G.Hamilton, M.P., Jones, A.G., Evans, R.L., Evans, S., Fourie, C.J.S., Garcia, X., Mountford, A., Spratt, J.E., SAMTEX MTElectrical anisotropy of South African lithosphere compared with seismic anisotropy from shear wave splitting analyses.Physics of the Earth and Planetary Interiors, In press, availableAfrica, South AfricaGeophysics - magnetotellurics
DS200712-0404
2006
Jones, A.G.Hamilton, M.P., Jones, A.G., Evans, R.L., Evans, S., Fourie, C.J.S., Mountford, SprattElectrical anisotropy of South African lithosphere compared with seismic from shear wave splitting analyses.Physics of the Earth and Planetary Interiors, Vol. 158, 2-4, Oct. 16, pp. 226-239.Africa, South AfricaGeophysics - seismics
DS200712-0621
2007
Jones, A.G.Lezaeta, P., Chave, A., Jones, A.G., evans, R.Source field effects in the auroral zone: evidence from the Slave Craton NW Canada.Physics of the Earth and Planetary Interiors, Vol. 164, 1-2, pp. 21-35.Canada, Northwest TerritoriesGeophysics
DS200812-0527
2008
Jones, A.G.Jones, A.G., Evans, R.L., Eaton, D.W.Velocity conductivity relationships for mantle mineral assemblages in Archean cratonic lithosphere based on a review of laboratory dat a and Hashin-Shtrikman extremal bonds.Lithos, In press available 59p.MantleUHP
DS200912-0197
2009
Jones, A.G.Eaton, D.W., Darbyshire, F., Evans, R.L., Grutter, H., Jones, A.G., Yuan, X.The elusive lithosphere asthenosphere boundary ( LAB) beneath cratons.Lithos, Vol. 109, 1-2, pp. 1-22.MantleBoundary
DS200912-0341
2009
Jones, A.G.Jones, A.G., Evans, Muller, Hamilton, Miensopust, Garcia, Cole, Ngwisanyi, Hutchins, Stoffel Fourie, Jelsma, Aravanis, Petit, Webb, WasborgArea selection for diamonds using magnetotellurics: examples from southern Africa.Lithos, In press - available 35p.Africa, South Africa, BotswanaGeophysics - magnetotellurics
DS200912-0342
2009
Jones, A.G.Jones, A.G., Evans, R.L., Eaton, D.W.Velocity conductivity relationships for mantle mineral assemblages in Archean cratonic lithosphere based on a review of laboratory dat a and Hashin Strikman boundsLithos, Vol. 109, 1-2, pp. 131-143.MantleMineral chemistry
DS200912-0723
2009
Jones, A.G.Spratt, J.E., Jones, A.G., Jackson, V.A., Collins, L., Avdeeva, A.Lithospheric geometry of the Wopmay orogen from a Slave Craton to Bear province magnetotelluric transect.Journal of Geophysical Research, Vol. 114, B1 B01101.CanadaGeophysics - magnetotellurics
DS201012-0118
2010
Jones, A.G.Cook, F.A., White, D.J., Jones, A.G., Eaton, D.W.S., Hall, J., Clowes, R.M.How the crust meets the mantle: lithoprobe perspectives on the Mohorovicic.Canadian Journal of Earth Sciences, Vol. 47, 4, pp. 315-351.Mantle, CanadaGeophysics - seismic
DS201012-0330
2010
Jones, A.G.Jones, A.G., Plomerova, J., Korja, T., Sodoudi, F., Spakman, W.Europe from the bottom up: a statistical examination of the central and northern European lithosphere asthenosphere boundary comparing seismological & EMLithos, in press available, 51p.EuropeGeophysics - seismics
DS201112-0312
2011
Jones, A.G.Evans, R.L., Jones, A.G., Garcia, X., Muller, M., Hamilton, Evans, Fourie, Spratt, Webb, Jelsma, HutchinsElectrical lithosphere beneath the Kaapvaal craton, southern Africa.Journal of Geophysical Research, Vol. 116, B4, B04105.Africa, South AfricaGeophysics - seismics
DS201112-0338
2011
Jones, A.G.Fullea, J., Muller, M.R., Jones, A.G.Electrical conductivity of continental lithospheric mantle from integrated geophysical and petrological modeling: application to the Kaapvaal craton and RehobothJournal of Geophysical Research, Vol. 116, B10, B10202Africa, South AfricaGeophysics - Rehoboth Terrane
DS201112-0672
2011
Jones, A.G.Miensopust, M.P., Jones, A.G., Muller, M.R., Garcia, X., Evans, R.L.Lithospheric structures and Precambrian terrane boundaries in northeastern Botswana revealed through magnetotelluric profiling as part of southern AfricanJournal of Geophysical Research, Vol. 116, B02401Africa, BotswanaCraton, Zimbabwe
DS201112-0673
2011
Jones, A.G.Miensopust, M.P., Jones, A.G., Muller, M.R., Garcia, X., Evans, R.L.Lithospheric structures and Precambrian terrane boundaries in northeastern Botswana revealed through magnetotelluric profiling as part of Southern Africa...Journal of Geophysical Research, Vol. 116, B02401 21p.Africa, BotswanaGeophysics - magnetotellurics
DS201312-0009
2013
Jones, A.G.Afonso, J.C., Fullea, J., Connolly, J., Rawlinson, N., Yang, Y., Jones, A.G.Multi observable thermochemical tomography: a new framework in integrated studies of the lithosphere.Goldschmidt 2013, AbstractMantleGeothermometry
DS201312-0446
2013
Jones, A.G.Jones, A.G., Fishwick, S., Evans, R.L., Muller, M.Velocity conductivity relations for cratonic lithosphere and their application: examples of southern Africa.Geochemistry, Geophysics, Geosystems: G3, Vol. 14, 4, pp. 806-827.Africa, South AfricaGeophysics
DS201412-0434
2014
Jones, A.G.Jones, A.G., Ledo, J., Ferguson, I.J., Craven, J.A., Unswrth, M.J., Chouteau, M., Spratt, J.E., Enkin, R.The electrical resistivity of Canada's lithosphere and correlation with other parameters: contributions from lithoprobe and other programmes.Canadian Journal of Earth Sciences, Vol. 51, 6, pp. 573-617.CanadaGeophysics
DS201412-0456
2013
Jones, A.G.Khoza, T.D., Jones, A.G., Muller, M.R., Evans, R.L., Miensopust, M.P., Webb, S.J.Lithospheric structure of an Archean craton and adjacent mobile belt revealed from 2-D and 3-D inversion of magnetotelluric data: example from southern Congo craton in northern Namibia.Journal of Geophysical Research, Vol. 118, 8, pp. 4378-4397.Africa, NamibiaGeophysics - tellurics
DS201412-0878
2013
Jones, A.G.Spratt, J.E., Skulski, T., Craven, J.A., Jones, A.G., Snyder, D.B., Kiyan, D.Magnetotelluric investigations of the lithosphere beneath the central Rae craton, maIn land Nunavut, Canada.Journal of Geophysical Research, Vol. 119, pp. 2415-2439.Canada, NunavutGeophysics - magnetotellurics
DS201712-2667
2018
Jones, A.G.Abdelsalam, G., Atekwana, E., Elsenbeck, J., Jones, A.G., Chikambwe, E.Imaging Precambrian lithospheric structure in Zambia using electromagnetic methods.Gondwana Research, Vol. 54, pp. 38-49.Africa, Zambia, Malawigeophysics

Abstract: The Precambrian geology of eastern Zambia and Malawi is highly complex due to multiple episodes of rifting and collision, particularly during the formation of Greater Gondwana as a product of the Neoproterozoic Pan-African Orogeny. The lithospheric structure and extent of known Precambrian tectonic entities of the region are poorly known as there have been to date few detailed geophysical studies to probe them. Herein, we present results from electromagnetic lithospheric imaging across Zambia into southern Malawi using the magnetotelluric method complemented by high-resolution aeromagnetic data of the upper crust in order to explore the extent and geometry of Precambrian structures in the region. We focus particularly on determining the extent of subcontinental lithospheric mantle (SCLM) beneath the Archean-Paleoproterozoic cratonic Bangweulu Block and the Mesoproterozoic-Neoproterozoic Irumide and Southern Irumide Orogenic Belts. We also focus on imaging the boundaries between these tectonic entities, particularly the boundary between the Irumide and Southern Irumide Belts. The thickest and most resistive lithosphere is found beneath the Bangweulu Block, as anticipated for stable cratonic lithosphere. Whereas the lithospheric thickness estimates beneath the Irumide Belt match those determined for other orogenic belts, the Southern Irumide Belt lithosphere is substantially thicker similar to that of the Bangweulu Block to the north. We interpret the thicker lithosphere beneath the Southern Irumide Belt as due to preservation of a cratonic nucleus (the pre-Mesoproterozoic Niassa Craton). A conductive mantle discontinuity is observed between the Irumide and Southern Irumide Belts directly beneath the Mwembeshi Shear Zone. We interpret this discontinuity as modified SCLM relating to a major suture zone. The lithospheric geometries determined from our study reveal tectonic features inferred from surficial studies and provide important details for the tectonothermal history of the region.
DS201712-2697
2017
Jones, A.G.Jones, A.G., Alfonso, J.C., Fullea, J.Geochemical and geophysical constrains on the dynamic topography of the southern African plateau.Geochemistry, Geophysics, Geosystems, Vol. 18, 10, pp. 3556-3575.Africa, South Africageodynamics

Abstract: The deep mantle African Superswell is considered to contribute to the topographic uplift of the Southern African Plateau, but dynamic support estimates vary wildly depending on the approach and data used. One reason for these large disparities is that the role of lithospheric structure, key in modulating deep dynamic contributions to elevation, is commonly ignored or oversimplified in convection studies. We use multiple high-quality geophysical data coupled with xenolith-based geochemical constraints to compute the isostatic lithospheric contribution to the elevation of the Plateau, facilitating isolation of the current dynamic component from the total observed elevation. We employ a multiobservable stochastic algorithm to invert geoid anomaly, surface-wave dispersion data, magnetotelluric data, and surface heat flow to predict elevation in a fully thermodynamically and internally-consistent manner. We find that a compositionally layered 230?±?7 km thick lithosphere is required to simultaneously fit all four data types, in agreement with abundant independent xenolith evidence. Our stochastic modeling indicates a lithospheric contribution to elevation of the order of 670 m, which implies dynamic support arising from the convecting sublithospheric mantle of ?650 m. Our results have important implications for the understanding of lithospheric-deep mantle feedback mechanisms and for calibrating dynamic topography estimates from global convection studies.
DS201801-0055
2018
Jones, A.G.Sarfian, E., Evans, R.L, Abdelsalam, M.G., Atekwana, E., Elsenbeck, J., Jones, A.G., Chikambwe, E..Imaging Precambrian lithospheric structure in Zambia using electromagnetic methods.Gondwana Research, Vol. 54, pp. 38-49.Africa, Zambiageophysics -em
DS201802-0263
2018
Jones, A.G.Sarafian, E., Evans, R.L., Abdelsalam, M.G., Atekwana, E., Elsenbeck, J., Jones, A.G., Chikambwe, E.Imaging Precambrian lithospheric structure in Zambia using electromagnetic methods.Gondwana Research, Vol. 54, pp. 38-49.Africa, Zambiageophysics

Abstract: The Precambrian geology of eastern Zambia and Malawi is highly complex due to multiple episodes of rifting and collision, particularly during the formation of Greater Gondwana as a product of the Neoproterozoic Pan-African Orogeny. The lithospheric structure and extent of known Precambrian tectonic entities of the region are poorly known as there have been to date few detailed geophysical studies to probe them. Herein, we present results from electromagnetic lithospheric imaging across Zambia into southern Malawi using the magnetotelluric method complemented by high-resolution aeromagnetic data of the upper crust in order to explore the extent and geometry of Precambrian structures in the region. We focus particularly on determining the extent of subcontinental lithospheric mantle (SCLM) beneath the Archean-Paleoproterozoic cratonic Bangweulu Block and the Mesoproterozoic-Neoproterozoic Irumide and Southern Irumide Orogenic Belts. We also focus on imaging the boundaries between these tectonic entities, particularly the boundary between the Irumide and Southern Irumide Belts. The thickest and most resistive lithosphere is found beneath the Bangweulu Block, as anticipated for stable cratonic lithosphere. Whereas the lithospheric thickness estimates beneath the Irumide Belt match those determined for other orogenic belts, the Southern Irumide Belt lithosphere is substantially thicker similar to that of the Bangweulu Block to the north. We interpret the thicker lithosphere beneath the Southern Irumide Belt as due to preservation of a cratonic nucleus (the pre-Mesoproterozoic Niassa Craton). A conductive mantle discontinuity is observed between the Irumide and Southern Irumide Belts directly beneath the Mwembeshi Shear Zone. We interpret this discontinuity as modified SCLM relating to a major suture zone. The lithospheric geometries determined from our study reveal tectonic features inferred from surficial studies and provide important details for the tectonothermal history of the region.
DS201903-0507
2019
Jones, A.G.Evans, R.L., Elsenbeck, J., Zhu, J., Abelsalam, M.G., Sarafian, E., Mutamina, D., Chilongola, F., Atekwan, E., Jones, A.G.Structure of the lithosphere beneath the Barotse Basin, western Zambia from magnetotelluric data.Tectonics, in press available Africa, Zambiamelting

Abstract: A magnetotelluric survey in the Barotse Basin of western Zambia shows clear evidence for thinned lithosphere beneath an orogenic belt. The uppermost asthenosphere, at a depth of 60-70 km, is highly conductive, suggestive of the presence of a small amount of partial melt, despite the fact that there is no surface expression of volcanism in the region. Although the data support the presence of thicker cratonic lithosphere to the southeast of the basin, the lithospheric thickness is not well resolved and models show variations ranging from ~80 to 150 km in this region. Similarly variable is the conductivity of the mantle beneath the basin and immediately beneath the cratonic lithosphere to the southeast, although the conductivity is required to be elevated compared to normal lithospheric mantle. In a general sense, two classes of model are compatible with the magnetotelluric data: one with a moderately conductive mantle and one with more elevated conductivities. This latter class would be consistent with the impingement of a stringer of plume?fed melt beneath the cratonic lithosphere, with the melt migrating upslope to thermally erode lithosphere beneath the orogenic belt that is overlain by the Barotse Basin. Such processes are potentially important for intraplate volcanism and also for development or propagation of rifting as lithosphere is thinned and weakened by melt. Both models show clear evidence for thinning of the lithosphere beneath the orogenic belt, consistent with elevated heat flow data in the region.
DS201904-0733
2019
Jones, A.G.Evans, R.L., Elsenbeck, J., Zhu, J., Abdelsalam, M.G., Sarafian, E., Mutamina, D., Chilongola, F., Atekwana, E.A., Jones, A.G.Structure of the lithosphere beneath the Barotse basin, western Zambia, from magnetotelluric data.Tectonics, Vol. 38, 2, pp. 666-686.Africa, Zambiageophysics

Abstract: A magnetotelluric survey in the Barotse Basin of western Zambia shows clear evidence for thinned lithosphere beneath an orogenic belt. The uppermost asthenosphere, at a depth of 60-70 km, is highly conductive, suggestive of the presence of a small amount of partial melt, despite the fact that there is no surface expression of volcanism in the region. Although the data support the presence of thicker cratonic lithosphere to the southeast of the basin, the lithospheric thickness is not well resolved and models show variations ranging from ~80 to 150 km in this region. Similarly variable is the conductivity of the mantle beneath the basin and immediately beneath the cratonic lithosphere to the southeast, although the conductivity is required to be elevated compared to normal lithospheric mantle. In a general sense, two classes of model are compatible with the magnetotelluric data: one with a moderately conductive mantle and one with more elevated conductivities. This latter class would be consistent with the impingement of a stringer of plume?fed melt beneath the cratonic lithosphere, with the melt migrating upslope to thermally erode lithosphere beneath the orogenic belt that is overlain by the Barotse Basin. Such processes are potentially important for intraplate volcanism and also for development or propagation of rifting as lithosphere is thinned and weakened by melt. Both models show clear evidence for thinning of the lithosphere beneath the orogenic belt, consistent with elevated heat flow data in the region.
DS202106-0950
2021
Jones, A.G.Le Pape, F., Jones, A.G., Jessell, M.W., Hogg, C., Siebenaller, L., Perrouty, S., Tour, A., Oiuya, P., Boren, G.The nature pf the southern West Africa craton lithosphere inferred from its electrical resistivity.Precambrian Research, Vol. 358, 106190, 15p. Pdf Africageophysics

Abstract: The West-African craton is defined by a combination of Archean and Palaeoproterozoic rocks that stabilised at ~2 Ga towards the end of the Paleoproterozoic Eburnean Orogeny, and therefore may reflect the transition from Archean to modern tectonic processes. Exploring its present lithospheric architecture aids further understanding of not only the craton’s stability through its history but also its formation. We investigate the lithospheric structure of the craton through analysing and modelling magnetotelluric (MT) data from a 500-km-long east-west profile in northern Ghana and southern Burkina Faso crossing part of the Baoulé-Mossi Domain and reaching the Volta Basin in the south-eastern part of the craton. Although the MT stations are along a 2D profile, due to the complexity of the structures characterising the area, 3D resistivity modelling of the data is performed to obtain insights on the thermal signature and composition of the subcontinental lithosphere beneath the area. The thermal structure and water content estimates from different resistivity models highlight a strong dependence on the starting model in the 3D inversions, but still enable us to put constraints on the deep structure of the craton. The present?day thermal lithosphere?asthenosphere boundary (LAB) depth is estimated to be at least 250 km beneath the Baoulé-Mossi domain. The area likely transitions from a cold and thick lithosphere with relatively low water content into thinner, more fertile lithosphere below the Volta Basin. Although the inferred amount of water could be explained by Paleoproterozoic subduction processes involved in the formation of the Baoulé-Mossi domain, later enrichment of the lithosphere cannot be excluded.
DS1999-0340
1999
Jones, A.J.Jones, A.J.Imaging the continental upper mantle using electromagnetic methodsLithos, Vol. 48, No. 1-4, Sept. pp. 57-80.MantleGeophysics - electromagnetic (electromagnetic)
DS1995-0891
1995
Jones, A.L.Jones, A.L., Miller, A.R., Armitage, A.E., MacRae, N.D.Lamprophyre dikes of the Christopher Island Formation, Thirty Mile Lake, District of Keewatin.Geological Survey of Canada, Paper 1995-C, pp. 187-194.Northwest TerritoriesLamprophyre dykes
DS1995-1140
1995
Jones, A.L.MacRae, N.D., Armitage, A.E., Jones, A.L.A Diamondiferous lamprophyre dike, Gibson Lake area, NorthwestTerritories.International Geology Review, Vol. 37, pp. 212-229.Northwest TerritoriesLamprophyre, diamond, Deposit -Akluilak dike
DS1997-0564
1997
Jones, A.L.Jones, A.L.Petrology, geochemistry and diamond potential of Christopher Island Formation lamprophyre dykes, Thirty Mile Lake area, Central Churchill Province.University of Western Ontario, MSc.ManitobaLamprophyres - Christopher Island dikes
DS1982-0301
1982
Jones, A.P.Jones, A.P., Dawson, J.B., Smith, J.V.Peridotites from the Olmani Scoria Cone, Northern TanzaniaProceedings of Third International Kimberlite Conference, TERRA COGNITA, ABSTRACT VOLUME., Vol. 2, No. 3, P. 221, (abstract.).Tanzania, East AfricaKimberlite, Dunite, Harzburgite, Lherzolite, Wehrlite
DS1982-0302
1982
Jones, A.P.Jones, A.P., Gaspar, J.C., Wyllie, P.J.Pervoskites and Opaque Minerals in Carbonatites Associated with kimberlites in South Africa.Eos, Vol. 63, No. 45, P. 1134, (abstract.).South AfricaBlank
DS1982-0303
1982
Jones, A.P.Jones, A.P., Smith, J.V.Electron Probe Analyses of Minette Minerals and Ion Probe Procedures for Micas.Geological Society of America (GSA), Vol. 14, No. 7, P. 523. (abstract.).United States, Colorado PlateauProbe Data, Geochemistry, The Thumb, Agathla Peak, Navajo Volcan
DS1982-0304
1982
Jones, A.P.Jones, A.P., Smith, J.V., Dawson, J.B.Mantle Metasomatism in 14 Veined Peridotites from Bultfontein Mine, South Africa.Journal of Geology, Vol. 90, PP. 435-453.South AfricaKimberlite, Genesis, Marid, Matsoku
DS1982-0317
1982
Jones, A.P.Karlsson, H.R., Jones, A.P.Zoned Labradorite Megacrysts in Xenolithic Picrite from Southwest iceland.Geological Society of America (GSA), Vol. 14, No. 7, P. 525. (abstract.).GlobalPetrology, Picrite
DS1983-0219
1983
Jones, A.P.Exley, R.A., Jones, A.P.87 Sr 86 Sr in Kimberlitic Carbonates by Ion Microprobe: Hydrothermal: Alteration, Crustal Contamination and Relation To Carbonatite.Contributions to Mineralogy and Petrology, Vol. 83, No. 3-4, PP. 288-292.South AfricaAnalyses, Microprobe, Alteration,strontium
DS1983-0333
1983
Jones, A.P.Jones, A.P., Smith, J.V., Dawson, J.B.Glasses in Mantle Xenoliths from Olmani, TanzaniaJournal of GEOLOGY, Vol. 91, No. 2, PP. 167-178.Tanzania, East AfricaPetrology
DS1983-0334
1983
Jones, A.P.Jones, A.P., Smith, J.V., Dawson, J.B., Hansen, E.C.Metamorphism, Partial Melting, and K-metasomatism of Garnets capolite-kyanite Granulite Xenoliths from Lashaine, Tanzania.Journal of GEOLOGY, Vol. 91, No. 2, PP. 143- 166.Tanzania, East AfricaBlank
DS1984-0384
1984
Jones, A.P.Jones, A.P., Wyllie, P.J.Minor Elements in Perovskite from Kimberlites and Distribution of Rare Earth Elements- an Electron Probe Study.Earth and Planetary Science Letters, Vol. 69, No. 1, JULY PP. 128-140.South Africa, United States, Kentucky, New York, Central States, AppalachiaRare Earth Elements (ree), Geochemistry
DS1984-0631
1984
Jones, A.P.Scatena-Wachel, D.E., Jones, A.P.Primary Baddeleyite Zr O2 in Kimberlite from Benfontein South Africa.Mineralogical Magazine., Vol. 48, No. 347, PT. 2, JUNE PP. 257-262.South AfricaMineralogy, Zirconium
DS1984-0779
1984
Jones, A.P.Wyllie, P.J., Jones, A.P.Experimental Dat a Bearing on the Origin of Carbonatites, With Particular Reference to the Mountain Pass Rare Earth Deposit.American Institute of Mining, Metallurgical, and Petroleum Engineers (AIME), PP. 935-949.United States, West Coast, CaliforniaCarbonatite, Rare Earth Elements (ree), Geochemistry
DS1985-0140
1985
Jones, A.P.Dawson, J.B., Smith, J.V., Jones, A.P.A Comparative Study of Bulk Rock and Mineral Chemistry of Olivine Melilitites and Associated Rocks from East and South Africa.Neues Jahrbuch f?r Mineralogie, Vol. S 152, No. 2, PP. 143-175.South Africa, East AfricaMineral Chemistry
DS1985-0311
1985
Jones, A.P.Jones, A.P., Ekambaram, V.New Ina a Analysis of a Mantle Derived Titanate Mineral of The Crichtonite Series, with Particular Reference to the Rareearth Elements.American Mineralogist., Vol. 70, PP. 414-418.South AfricaBultfontein, Rare Earth Elements (ree), Mineral Chemistry
DS1985-0312
1985
Jones, A.P.Jones, A.P., Larsen, L.M.Geochemistry and rare earth elements (REE) minerals of nepheline syenites from theMotzfeldtCentre, South GreenlandAmerican Mineralogist, Vol. 70, pp. 1087-1100GreenlandRare Earth Elements (ree), Larvikite, Mineral Chemistry, Rare Earth
DS1985-0313
1985
Jones, A.P.Jones, A.P., Smith, J.V.Phlogopite and associated minerals from Permian minettes inDevon, southEnglandBulletin. Geological Society Finland, Vol. 57, pt. 1-2, pp. 89-102GlobalMinette, Comparison Of Kimberlitic
DS1985-0314
1985
Jones, A.P.Jones, A.P., Wyllie, P.J.Paragenetic Trends of Oxide Minerals in Carbonate Rich Kimberlites, with New Analyses from the Benfontein Sill, South Africa.Journal of PETROLOGY, Vol. 26, No. 1, PP. 210-222.South AfricaIlmenite, Spinel, Textures, Petrography, Perovskite
DS1986-0409
1986
Jones, A.P.Jones, A.P., Wyllie, P.J.Solubility of rare earth elements in carbonatite magmas,indicated by the liquidus surface in the CaCO3 Ca (OH) 2 la (OH) 3 at 1 K bar pressureApplied Geochemistry, Vol. 1, No. 1, Jan. Feb. pp. 95-102CaliforniaCarbonatite, Mountain Pass, Rare earth
DS1986-0410
1986
Jones, A.P.Jones, A.P., Wyllie, P.J.Synthetic rare earth elements (REE) carbonatite magmasTerra Cognita, Vol. 6, No. 1, Winter p. 37. (abstract.)GlobalRare earths, Carbonatite
DS1987-0321
1987
Jones, A.P.Jones, A.P.A titanate mineral, the quintessential mantle component?Terra Cognita, Conference abstracts Oceanic and Continental Lithosphere:, Vol. 7, No. 4, Autumn, abstract only p. 617GlobalBlank
DS1989-0722
1989
Jones, A.P.Jones, A.P.Upper-mantle enrichment by kimberlitic or carbonatitic magmatismCarbonatites -Genesis and Evolution, Ed. K. Bell Unwin Hyman Publ, pp. 448-463South AfricaMantle Metasomatism, Kimberlite/carbonatite
DS1993-1777
1993
Jones, A.P.Wyllie, P.J., Jones, A.P., Deng, J.Carbonatite magmas and rare earth elements (REE): some liquidus phaseRare earth Minerals: chemistry, origin and ore deposits, International Geological Correlation Programme (IGCP) Project, pp. 163-165.GlobalCarbonatite, Genesis
DS1994-0307
1994
Jones, A.P.Church, A.A., Jones, A.P.Hollow natrocarbonate lapilli from the 1992 eruption of Oldoinyo-Lengai, Tanzania.Journal of Geological Society of London, Vol. 151, January pp. 59-63.TanzaniaNatrocarbonate
DS1995-0321
1995
Jones, A.P.Church, A.A., Jones, A.P.Silicate carbonatite immiscibility at Oldoinyo LengaiGeological Society Africa 10th. Conference Oct. Nairobi, p. 122. Abstract.Tanzaniacarbonatite, Deposit -Oldoinyo Lengai
DS1995-0322
1995
Jones, A.P.Church, A.A., Jones, A.P.Silicate carbonate immiscibility at Oldoinyo LengaiJournal of Petrology, Vol. 96, No. 4, pp. 869-889.TanzaniaNatrocarbonatite, Deposit -Oldoinyo Lengai
DS1995-0614
1995
Jones, A.P.Genge, M.J., Jones, A.P., Price, G.D.An infrared and Raman study of carbonate glasses: implications for the structure of carbonatite magmas.Geochimica et Cosmochimica Acta, Vol. 59, No. 5, pp. 927-937.GlobalMagma -carbonatite, Mantle metasomatism, Melt, structure
DS1995-0615
1995
Jones, A.P.Genge, M.J., Price, G.D., Jones, A.P.Molecular dynamics simulations of CaCO3 melts -mantle pressure/temperatures: implications for carbonatite.Earth and Planetary Science Letters, Vol. 131, No. 3-4, April pp. 225-238.GlobalCarbonatite
DS1995-0888
1995
Jones, A.P.Johnson, L.H., Jones, A.P.Ultramafic xenoliths and megacrysts from Deeti tuff cone, northernTanzania.Geological Society Africa 10th. Conference Oct. Nairobi, p. 123-4. Abstract.TanzaniaCarbonatite, Deposit -Deeti
DS1995-0892
1995
Jones, A.P.Jones, A.P., Dobson, D.P., Genge, M.Comment on physical properties of carbonatite magmas inferred from molten salt data, mantle chambers....Geological Magazine, Vol. 132, No. 1, p. 121.GlobalMagma, Carbonatite -silicate
DS1995-0893
1995
Jones, A.P.Jones, A.P., Taniguchi, T., Dobson, D., Milledge, H.J.Experimental nucleation and growth of diamond from carbonate graphitesystems.Geological Society Africa 10th. Conference Oct. Nairobi, p. 119. Abstract.GlobalPetrology -experimental, Diamond
DS1995-0894
1995
Jones, A.P.Jones, A.P., Taniguchi, T., Dobson, D., Rabe, R., MilledgeExperimental nucleation and growth of diamond from carbonate-graphitesystems.Proceedings of the Sixth International Kimberlite Conference Abstracts, pp. 269-270.GlobalPetrology -experimental, Diamond nucleation
DS1996-0697
1996
Jones, A.P.Jones, A.P., Wall, F., Williams, C.T.Rare earth minerals chemistry, origin and ore depositsChapman Hall, MSA., MSA No. 7, 360p. approx. $ 80.00 United StatesGlobalBook - table of contents, Rare earth minerals
DS1996-0698
1996
Jones, A.P.Jones, A.P., Wall, F., Williams, C.T.Rare earth minerals: chemistry, origin and ore deposits.Specific chapters cited separately.Mineralogical Soc. Series, No. 7, 372p. approx. $60.00USGlobalRare earth minerals, Carbonatite
DS1996-1565
1996
Jones, A.P.Wyllie, P.J., Jones, A.P., Deng, J.Rare earth elements in carbonate rich melts from mantle to crustMineralogical Soc. Series, No. 7, pp. 77-104.MantleRare earth minerals, Carbonatite, alkaline rocks
DS1997-0561
1997
Jones, A.P.Johnson, L.H., Jones, A.P., Church, A.A., Taylor, W.R.Ultramafic xenoliths and megacrysts from a melilitite tuff cone, Deeti, northern Tanzania.Journal of African Earth Sciences, Vol. 25, No. 1, July pp. 29-42.TanzaniaMelilitite, Xenoliths
DS1998-0703
1998
Jones, A.P.Jones, A.P., Dobson, D., Milledge, Tabiguchi, LitvinExperiments with low T potassic carbonatitic melts, fluids and diamonds7th International Kimberlite Conference Abstract, pp. 386-8.GlobalCarbonatite, Petrology - experimental
DS2000-0456
2000
Jones, A.P.Jones, A.P., Kostula, T., Stoppa, F., Woolley, A.R.Petrography and mineral chemistry of mantle xenoliths in a carbonate rich meliltic tuff from Mt. Vulture.Mineralogical Magazine, Vol. 64, No. 4, Aug. pp. 593-614.ItalyXenoliths, Melilitite
DS2000-0828
2000
Jones, A.P.Rosatelli, G., Stopia, F., Jones, A.P.Intrusive calcite carbonate occurrence from Mt. Vulture volcano, southern Italy.Mineralogical Magazine, Vol. 64, No. 4, Aug. 1, pp.615-24.ItalyMelilite
DS2000-0829
2000
Jones, A.P.Rosatelli, G., Stoppa, F., Jones, A.P.Intrusive calcite carbonatite occurrence from Mt. Vulture volcano, southern Italy.Mineralogical Magazine, Vol. 64, No. 4, Aug. pp. 615-24.ItalyXenoliths, Melilitite
DS2001-0692
2001
Jones, A.P.Litvin, Yu.A., Jones, A.P., Beard, Divaev, ZharikovCrystallization of diamond and syngenetic minerals in melts of Diamondiferous carbonatites of Chagatai MassifDoklady, Vol.381A, No.9, Nov-Dec. pp. 1066-9.Russia, UzbekistanCarbonatite - diamond bearing, Deposit - Chagatai Massif
DS2002-0400
2002
Jones, A.P.Downes, H., Kostoula, T., Jones, A.P., Beard, A.D., Thirwall, M.F., Bodinier, J.L.Geochemistry and Sr Nd isotopic compositions of mantle xenoliths from the MonteContributions to Mineralogy and Petrology, Vol. 144, 1, Oct. pp. 78-92.ItalyMelilite - carbonatite - not specific to diamonds
DS2002-0789
2002
Jones, A.P.Jones, A.P., Price, G.D., rice, N.J., DeCarli, P.S., Clegg, R.A.Impact induced melting and the development of large igneous provincesEarth and Planetary Science Letters, Vol. 202, 3-4, pp. 551-61.GlobalMagmatism - not specific to diamonds
DS2002-1772
2002
Jones, A.P.Zedgenizov, D.A., Pokhilenko, N.P., Rylov, G.M., Milledge, J.H., Jones, A.P.Assorted diamond population from Snap lake mine ( Canada)18th. International Mineralogical Association Sept. 1-6, Edinburgh, abstract p.116Northwest TerritoriesDiamond - morphology
DS2003-0668
2003
Jones, A.P.Jones, A.P., Milledge, H.J., Beard, A.D.A new nitride mineral in carbonado8ikc, Www.venuewest.com/8ikc/program.htm, Session 3, POSTER abstractBrazilDiamonds - mineralogy
DS2003-1384
2003
Jones, A.P.Tomlinson, E.L., Jones, A.P., Milledge, H.J.Multiple fluids in diamond coat and their role in diamond growth8ikc, Www.venuewest.com/8ikc/program.htm, Session 3, POSTER abstractGlobalDiamonds - inclusions
DS200512-1094
2005
Jones, A.P.Tomlinson, E., De Schrijver, I., De Corte, K., Jones, A.P., Moens, L., Vanhaecke, F.Trace element compositions of submicroscopic inclusions in coated diamond: a tool for understanding diamond petrogenesis.Geochimica et Cosmochimica Acta, Vol. 69, 19, Oct. 1, pp. 4719-4732.Africa, Democratic Republic of CongoSilicate melt inclusions, Group 1, diamond inclusions
DS200612-0605
2006
Jones, A.P.Howell, D., Jones, A.P., Dobson, D.P., Milledge, H.J., Harris, J.W.Birefringence analysis of diamond utilising the MetriPol system.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 268. abstract only.TechnologyDiamond morphology
DS200612-1434
2006
Jones, A.P.Tomlinson, E.L., Jones, A.P., Harris, J.W.Co-existing fluid and silicate inclusions in mantle diamond.Earth and Planetary Science Letters, Vol. 250, 3-4, pp. 581-595.MantleDiamond inclusions
DS200612-1436
2006
JOnes, A.P.Trickett, S.K., JOnes, A.P., Field, M.Mapping lithofacies within the D/K1 kimberlite pipe, Lethakane, Botswana: a multi-disciplinary approach.Emplacement Workshop held September, 5p. abstractAfrica, BotswanaDeposit - D/K1, petrography
DS200712-1087
2007
Jones, A.P.Tomlinon, E.L., McMillan, P.F., Zhang, M., Jones, A.P., Redfern, S.A.T.Quartz bearing C-O-H fluid inclusions diamond: retracing the pressure-temperature path in the mantle using calibrated high temperature IR spectroscopy.Geochimica et Cosmochimica Acta, on line in press available, 10p.Africa, Democratic Republic of CongoDeposit - Mbuji Mayi - mineralogy
DS200712-1089
2006
Jones, A.P.Tomlinson, E.L., Jones, A.P., Harris, J.W.Co-existing fluid and silicate inclusions in mantle diamond.Earth and Planetary Science Letters, Vol. 250, 3-4, Oct. 30, pp. 581-595.MantleDiamond inclusions
DS200812-1132
2008
Jones, A.P.Stoppa, F., Sharygin, V.V., Jones, A.P.Mantle metasomatism and alkali carbonatite silicate phase reaction as inferred by Nyerereite inclusions in Vulture volcano carbonatite rocks.9IKC.com, 3p. extended abstractEurope, ItalyCarbonatite
DS200912-0343
2009
Jones, A.P.Jones, A.P., Oganov, A.Superdeep carbonate melts in the Earth.Goldschmidt Conference 2009, p. A601 Abstract.MantleMelting
DS201012-0292
2010
Jones, A.P.Howell, D., Wood, I.G., Dobson, D.P., Jones, A.P., Nasdala, L., Harris, J.W.Quantifying strain birefringence halos around inclusions in diamond.Contributions to Mineralogy and Petrology, Vol. 160, pp. 705-717.TechnologyDiamond genesis, inclusion remnant pressure
DS201112-0067
2011
Jones, A.P.Basu, S., Mikhail, S., Jones, A.P., Verchovsky, A.B.Comparing carbon isotopic signatures between meteorites and terrestrial mantle samples: need for reassessment of carbon composition of Earth's mantle.Goldschmidt Conference 2011, abstract p.497.MantleCarbonatite, diamonds
DS201112-0145
2011
Jones, A.P.Carmody, L., Jones, A.P., Kilburn, C., Steele, A., Bower, D.A first Raman study of fluid inclusions within xenoliths from Oldoinyo Lengai, Tanzania.Peralk-Carb 2011, workshop held Tubingen Germany June 16-18, PosterAfrica, TanzaniaCarbonatite
DS201112-0146
2011
Jones, A.P.Carmody, L., Jones, A.P., Kilburn, C., Steele, A., Bower, D.A first Raman study of fluid inclusions within xenoliths from Oldoinyo Lengai, Tanzania.Peralk-Carb 2011... workshop June 16-18, Tubingen, Germany, Abstract p.15-16.Africa, TanzaniaCarbonatite
DS201112-0147
2011
Jones, A.P.Carmody, L., Jones, A.P., Kilburn, C., Steele, A., Bower, D.A first Raman study of fluid inclusions within xenoliths from Oldoinyo Lengai, Tanzania.Peralk-Carb 2011... workshop June 16-18, Tubingen, Germany, Abstract p.15-16.Africa, TanzaniaCarbonatite
DS201112-1051
2011
Jones, A.P.Tomlinson, E.L., Howell, D., Jones, A.P., Frost, D.J.Characteristics of HPHT diamond grown at sub-lithosphere conditions (10-20 GPa).Diamond and Related Materials, Vol. 20, 1, Jan. pp. 11-17.TechnologyUHP
DS201212-0311
2012
Jones, A.P.Howell, D., Piazolo, S., Dobson, D.P., Wood, I.G., Jones, A.P., Watte, N., Frost, D.J., Fisher, D., Griffin, W.L.Quantitative characterization of plastic deformation of single diamond crystals: a high pressure high temperature (HPHT) experimental deformation study combines with electron backscatter diffraction.Diamond and Related Materials, Vol. 30, pp. 20-30.TechnologyDiamond morphology
DS201312-0058
2013
Jones, A.P.Basu, S., Jones, A.P., Verchovsky, A.B., Kelley, S.P., Stuart, F.M.An overview of noble gas (He,Ne, Ar, Xe) contents and isotope signals in terrestrial diamond.Earth Science Reviews, Vol. 126, pp. 370-389.TechnologyMineral chemistry
DS201312-0062
2013
Jones, A.P.Beard, A.D., Howard, K., Carmody, L., Jones, A.P.The origin of melanophlogite, a clathrate mineral, in natrocarbonatite lava at Oldoinyo Lengai, Tanzania.American Mineralogist, Vol. 98, pp. 1998-2006.Africa, TanzaniaCarbonatite
DS201312-0126
2012
Jones, A.P.Carmody, L., Jones, A.P., Mikhail, S., Bower, D.M., Steele, A., Lawrence, D.M., Verchovsky, A.B., Buikin, A., Taylor, L.A.Is the World's only carbonatite volcano a dry anhydrous system?Geological Society of America Annual Meeting abstract, Paper 157-2, 1/2p. AbstractAfrica, TanzaniaDeposit - Oldoinyo Lengai
DS201312-0447
2013
Jones, A.P.Jones, A.P., Basu, S.Is diamond a repository of mantle helium and noble gases?Goldschmidt 2013, AbstractMantleRatio in diamond pipes
DS201312-0448
2013
Jones, A.P.Jones, A.P., Genge, M., Carmody, L.Carbonate melts and carbonatites.Reviews in Mineralogy and Geochemistry, Vol. 75, pp. 289-322.MantleCarbonatite
DS201312-0602
2013
Jones, A.P.Mikhail, S., Dobosi, G., Verchovsky, A.B., Kurat, G., Jones, A.P.Peridotitic and websteritic diamondites provide new information regarding mantle melting and metasomatism induced through the subduction of crustal volatiles.Geochimica et Cosmochimica Acta, Vol. 107, Apr. 15, pp. 1-11.MantleDiamondites
DS201412-0577
2014
Jones, A.P.Mikhail, S., Guillermier, C., Franchi, I.A., Beard, A.D., Crispin, K., Verchovsky, A.B., Jones, A.P., Milledge, H.J.Empirical evidence for the fractionation of carbon isotopes between diamond and iron carbide from the Earth's mantle.Geochemistry, Geophysics, Geosystems: G3, Vol. 15, 4, pp. 855-866.MantleGeochronology
DS201412-0581
2014
Jones, A.P.Mikhail, S., Verchovsky, A.B., Howell, D., Hutchison, M.T., Southworth, R., Thomson, A.R., Warburton, P., Jones, A.P., Milledge, H.J.Constraining the internal variability of the stable isotopes of carbon and nitrogen within mantle diamonds.Chemical Geology, Vol. 366, pp. 14-23.Africa, Russia, South America, BrazilDiamond inclusions
DS201611-2116
2016
Jones, A.P.Jones, A.P., McMillan, P.F., Salzmann, C.G., Alvaro, M., Nestola, F., Prencipe, M., Dobson, D., Hazael, R., Moore, M.Structural characteristization of natural diamond shocked to 60 Gpa: implications for Earth and Planetary Systems.Lithos, in press available 25p.TechnologyNatural diamonds

Abstract: The possible presence of the high-density carbon polymorph with hexagonal symmetry known as "lonsdaleite" provides an important marker for shock impact events. It is typically considered to form as a metastable phase produced from graphite or other carbonaceous precursors. However, its existence has recently been called into question. Here we collected high-resolution synchrotron X-ray diffraction data for laboratory-shocked and natural impact diamonds that both show evidence for deviations from cubic symmetry, that would be consistent with the appearance of hexagonal stacking sequences. These results show that hexagonality can be achieved by shocking diamond as well as from graphite precursors. The diffraction results are analyzed in terms of a general model that describes intermediate stacking sequences between pure diamond (fully cubic) and "lonsdaleite" (fully hexagonal) phases, with provision made for ordered vs disordered stacking arrangements. This approach provides a "hexagonality index" that can be used to characterize and distinguish among samples that have experienced different degrees of shock or static high pressure-high temperature treatments. We have also examined the relative energetics of diamond and "lonsdaleite" structures using density functional theoretical (DFT) methods. The results set limits on the conditions under which a transformation between diamond and "lonsdaleite" structures can be achieved. Calculated Raman spectra provide an indicator for the presence of extended hexagonal stacking sequences within natural and laboratory-prepared samples. Our results show that comparable crystallographic structures may be developed by impact-generated shockwaves starting from ambient conditions using either of the two different allotropes of carbon (diamond, graphite). This broadens the scope for its occurrence in terrestrial and planetary systems.
DS201701-0016
2016
Jones, A.P.Jones, A.P., McMillan P.F., Salzmann, C.G., Alvaro, M., Nestola, F., Prencipe, M., Dobson, D., Hazael, R., Moore, M.Structual characterization of natural diamond shocked to 60 Gpa; implications for Earth and Planetary Systems.Lithos, In press availableTechnologyDiamond morphology

Abstract: The possible presence of the high-density carbon polymorph with hexagonal symmetry known as “lonsdaleite” provides an important marker for shock impact events. It is typically considered to form as a metastable phase produced from graphite or other carbonaceous precursors. However, its existence has recently been called into question. Here we collected high-resolution synchrotron X-ray diffraction data for laboratory-shocked and natural impact diamonds that both show evidence for deviations from cubic symmetry, that would be consistent with the appearance of hexagonal stacking sequences. These results show that hexagonality can be achieved by shocking diamond as well as from graphite precursors. The diffraction results are analyzed in terms of a general model that describes intermediate stacking sequences between pure diamond (fully cubic) and “lonsdaleite” (fully hexagonal) phases, with provision made for ordered vs disordered stacking arrangements. This approach provides a “hexagonality index” that can be used to characterize and distinguish among samples that have experienced different degrees of shock or static high pressure-high temperature treatments. We have also examined the relative energetics of diamond and “lonsdaleite” structures using density functional theoretical (DFT) methods. The results set limits on the conditions under which a transformation between diamond and “lonsdaleite” structures can be achieved. Calculated Raman spectra provide an indicator for the presence of extended hexagonal stacking sequences within natural and laboratory-prepared samples. Our results show that comparable crystallographic structures may be developed by impact-generated shockwaves starting from ambient conditions using either of the two different allotropes of carbon (diamond, graphite). This broadens the scope for its occurrence in terrestrial and planetary systems.
DS201908-1797
2019
Jones, A.P.Murri, M., Smith, R.L., McColl, K., Hart, M., Alvaro, M., Jones, A.P., Nemeth, P., Salzmann, C.G., Cora, F., Domeneghetti, M.C., Nestola, F., Sobolev, N.V., Vishnevsky, S.A., Logvinova, A.M., McMillan, P.F.Quantifying hexagonal stacking in diamond. ( lonsdaleite)Nature Scientific Reports, doi.org/10.1038/ s41598-019-46556-3 8p. PdfGlobaldiamond morphology, impact craters

Abstract: Diamond is a material of immense technological importance and an ancient signifier for wealth and societal status. In geology, diamond forms as part of the deep carbon cycle and typically displays a highly ordered cubic crystal structure. Impact diamonds, however, often exhibit structural disorder in the form of complex combinations of cubic and hexagonal stacking motifs. The structural characterization of such diamonds remains a challenge. Here, impact diamonds from the Popigai crater were characterized with a range of techniques. Using the MCDIFFaX approach for analysing X-ray diffraction data, hexagonality indices up to 40% were found. The effects of increasing amounts of hexagonal stacking on the Raman spectra of diamond were investigated computationally and found to be in excellent agreement with trends in the experimental spectra. Electron microscopy revealed nanoscale twinning within the cubic diamond structure. Our analyses lead us to propose a systematic protocol for assigning specific hexagonality attributes to the mineral designated as lonsdaleite among natural and synthetic samples.
DS201909-2076
2019
Jones, A.P.Piazzi, M., Morana, M., Coisson, M., Marone, F., Campione, M., Bindi, L., Jones, A.P., Ferrara, E., Alvaro, M.Multi-analytical characterization of Fe-rich magnetic inclusions in diamonds.Diamonds and Related Materials, in press available 36p. PdfAfrica, Ghanadeposit - Akwatia

Abstract: Magnetic mineral inclusions, as iron oxides or sulfides, occur quite rarely in natural diamonds. Nonetheless, they represent a key tool not only to unveil the conditions of formation of host diamonds, but also to get hints about the paleointensity of the geomagnetic field present at times of the Earth's history otherwise not accessible. This possibility is related to their capability to carry a remanent magnetization dependent on their magnetic history. However, comprehensive experimental studies on magnetic inclusions in diamonds have been rarely reported so far. Here we exploit X-ray diffraction, Synchrotron-based X-ray Tomographic Microscopy and Alternating Field Magnetometry to determine the crystallographic, morphological and magnetic properties of ferrimagnetic Fe-oxides entrapped in diamonds coming from Akwatia (Ghana). We exploit the methodology to estimate the natural remanence of the inclusions, associated to the Earth's magnetic field they experienced, and to get insights on the relative time of formation between host and inclusion systems. Furthermore, from the hysteresis loops and First Order Reversal Curves we determine qualitatively the anisotropy, size and domain state configuration of the magnetic grains constituting the inclusions.
DS201910-2292
2019
Jones, A.P.Piazzi, M., Morana, M., Coisson, M., Marone, F., Campione, M., Bindi, L., Jones, A.P., Ferrara, E., Alvaro, M.Multi-analytical characterization of Fe-rich magnetic inclusions in diamonds. Akwatiaresearchgate.net, June 18, 333866141 12p. PdfAfrica, Ghanadeposit - Akwatia

Abstract: Magnetic mineral inclusions, as iron oxides or sulfides, occur quite rarely in natural diamonds. Nonetheless, they represent a key tool not only to unveil the conditions of formation of host diamonds, but also to get hints about the paleointensity of the geomagnetic field present at times of the Earth's history otherwise not accessible. This possibility is related to their capability to carry a remanent magnetization dependent on their magnetic history. However, comprehensive experimental studies on magnetic inclusions in diamonds have been rarely reported so far. Here we exploit X-ray diffraction, Synchrotron-based X-ray Tomographic Microscopy and Alternating Field Magnetometry to determine the crystallographic, morphological and magnetic properties of ferrimagnetic Fe-oxides entrapped in diamonds coming from Akwatia (Ghana). We exploit the methodology to estimate the natural remanence of the inclusions, associated to the Earth's magnetic field they experienced, and to get insights on the relative time of formation between host and inclusion systems. Furthermore, from the hysteresis loops and First Order Reversal Curves we determine qualitatively the anisotropy, size and domain state configuration of the magnetic grains constituting the inclusions.
DS201911-2568
2019
Jones, A.P.Suarez, C.A., Edmonds, M., Jones, A.P.Earth catastrophes and their impact on the carbon cycle.Elements, Vol. 15, pp. 301-306.Mantlecarbon

Abstract: Carbon is one of the most important elements on Earth. It is the basis of life, it is stored and mobilized throughout the Earth from core to crust and it is the basis of the energy sources that are vital to human civilization. This issue will focus on the origins of carbon on Earth, the roles played by large-scale catastrophic carbon perturbations in mass extinctions, the movement and distribution of carbon in large igneous provinces, and the role carbon plays in icehouse-greenhouse climate transitions in deep time. Present-day carbon fluxes on Earth are changing rapidly, and it is of utmost importance that scientists understand Earth's carbon cycle to secure a sustainable future.
DS202011-2054
2020
Jones, A.P.Murri, M., Smith, R.L., McColl, K., Hart, M., Alvaro, M., Jones, A.P., Nemeth, P., Salzmann, C.G., Cora, F., Domeneghetti, M.C., Nestola, F., Sobolev, N.V., Vishnevsky, S.A., Logvinova, A.M., McMillan, P.F.Quantifying hexagonal stacking in diamond.Nature/scientific reports, 8p. PdfGlobalcrystallography

Abstract: Diamond is a material of immense technological importance and an ancient signifier for wealth and societal status. In geology, diamond forms as part of the deep carbon cycle and typically displays a highly ordered cubic crystal structure. Impact diamonds, however, often exhibit structural disorder in the form of complex combinations of cubic and hexagonal stacking motifs. The structural characterization of such diamonds remains a challenge. Here, impact diamonds from the Popigai crater were characterized with a range of techniques. Using the MCDIFFaX approach for analysing X-ray diffraction data, hexagonality indices up to 40% were found. The effects of increasing amounts of hexagonal stacking on the Raman spectra of diamond were investigated computationally and found to be in excellent agreement with trends in the experimental spectra. Electron microscopy revealed nanoscale twinning within the cubic diamond structure. Our analyses lead us to propose a systematic protocol for assigning specific hexagonality attributes to the mineral designated as lonsdaleite among natural and synthetic samples.
DS202203-0368
2021
Jones, A.P.Timmerman, S., Spivak, A.V., Jones, A.P.Carbonatitic melts and their role in diamond formation in the deep earth.Elements, Vol. 17, pp. 321-326.Mantlediamond genesis

Abstract: Carbonatitic high-density fluids and carbonate mineral inclusions in lithospheric and sub-lithospheric diamonds reveal comparable compositions to crustal carbonatites and, thus, support the presence of carbon-atitic melts to depths of at least the mantle transition zone (~410-660 km depth). Diamonds and high pressure-high temperature (HP-HT) experiments confirm the stability of lower mantle carbonates. Experiments also show that carbonate melts have extremely low viscosity in the upper mantle. Hence, carbonatitic melts may participate in the deep (mantle) carbon cycle and be highly effective metasomatic agents. Deep carbon in the upper mantle can be mobilized by metasomatic carbonatitic melts, which may have become increasingly volumetrically significant since the onset of carbonate subduction (~3 Ga) to the present day.
DS1985-0078
1985
Jones, A.S.Boulton, G.S., Smith, G.D., Jones, A.S., Newsome, J.Glacial Geology and Glaciology of the Last Mid Latitude Icesheets.Journal of the Geological Society of London., Vol. 142, No. 3, MAY PP. 447-474.United States, CanadaGlacial Dispersion
DS1975-1087
1979
Jones, B.Jones, B.Minerals in Depth. Diamonds. they are the Hardest Gemstones known But Not the Toughest.Rock And Gem., Vol. 11, No. 1, PP. 41-47; PP. 68-71.GlobalHistory, Diamonds Notable
DS1975-1088
1979
Jones, B.Jones, B.Diamonds. Pt. 1 and 2Rock Gem., Vol. 9, No. 1, PP. 40-44; 46-47; No. 2, PP. 48-54; 92-93.United StatesBlank
DS1975-1089
1979
Jones, B.Jones, B.Diamonds. their History Is as Colourful as their FireRock And Gem., Vol. 11, No. 2, FEBRUARY PP. 8; 50-55; 92-93.Russia, South AfricaHistory, Diamonds Notable
DS1982-0305
1982
Jones, B.Jones, B.Strategic Minerals.. there are Some We Can't Do Without Butmay.Rock And Gem., Vol. 12, No. 5, PP. 34-39; PP. 76-77.United StatesDiamonds, Kimberlite, Selenium, Cobalt, Chromium, Mercury, Titanium
DS1983-0335
1983
Jones, B.Jones, B.Minerals of BrasilRock And Gem., Vol. 13, No. 11, NOVEMBER, PP. 28-35.BrazilMineral Resources, Diamond
DS1983-0336
1983
Jones, B.Jones, B.Diamonds Revisited. they Have Been Swallowed, Smashed and Treasured.Rock And Gem., Vol. 13, No. 2, FEBRUARY PP. 28-34; PP. 76-77.GlobalHistory
DS1983-0337
1983
Jones, B.Jones, B.Diamonds RevisitedRock And Gem., Vol. 13, No. 2, PP. 28-32.United StatesBlank
DS1992-0804
1992
Jones, B.Jones, B.A mantle full of diamondsRock and GeM., Vol. 22, No. 6, June pp. 52-56, 96-97GlobalDiamonds, Popular geology
DS1993-0760
1993
Jones, B.Jones, B.Mineral erosionRock and GeM., Vol. 23, No. 10, pp. 52-56, 82-86.Africa, Asia, Brazil, China, Commonwealth of Independent States (CIS), India, NamibiaPopular account of alluvials, Diamonds
DS1993-0761
1993
Jones, B.Jones, B.Mineral erosion... affecting diamonds and diamond depositsRock and GeM., Vol. 23, No. 10, October pp. 52-56, 82-86.Africa, China, Brazil, RussiaAlluvial diamonds
DS1999-0341
1999
Jones, B.Jones, B.The lure of diamonds.. coveted everywhere.. found in exotic locations including America.Rock and GeM., April pp. 24-27.Arkansas, Colorado, WyomingNews, History - layman
DS201312-0931
2013
Jones, B.Uzzi, B., Mukherjee, S., Stringer, M., Jones, B.Atypical combinations and scientific impact .. ( creative ideas based on strong knowledge and in teamwork).Science, Vol. 342, 6157, pp. 468-472.TechnologyKnowledge base
DS1995-0895
1995
Jones, B.O.Jones, B.O.The future: is the mining industry part of it?Australian Institute of Mining and Metallurgy (AusIMM) Bulletin, No. 7, November pp. 48-53AustraliaEconomics, Mining industry
DS1975-0717
1978
Jones, C.Coates, J.N.M., Davies, J., Gould, D., Hutchins, D.G., Jones, C.The Kalatraverse One ReportBotswana Geological Survey, Bulletin. No. 21, 421P.Botswana, South AfricaGeology, Regional Tectonics
DS1993-0690
1993
Jones, C.A.Hollerbach, R., Jones, C.A.Influence of the earth's inner core on geomagnetic fluctuations andreversalsNature, Vol. 365, No. 6446, October 7, pp. 541-543MantleGeophysics, Crust-core, Geomagnetics
DS1994-1744
1994
Jones, C.E.Tarney, J., Jones, C.E.Trace element geochemistry of orogenic igneous rocks and crustal growthmodels.Journal of the Geological Society of London, Vol. 151, No. 5, Sept. pp. 855-868.GlobalGeochemistry, Igneous rocks
DS1997-1032
1997
Jones, C.H.Sheehan, A.F., Jones, C.H., Schneider, J.M.Contrasting lithospheric structure beneath the Colorado Plateau and GreatBasin: initial results from PASSCAL.Geophysical Res. Letters, Vol. 24, No. 21, Nov. 1, pp. 2609-12.Colorado PlateauGeophysics - seismics PASSCAL, Mantle
DS1998-0704
1998
Jones, C.H.Jones, C.H., Sonder, L.J., Unruh, J.R.Lithospheric gravitational potential energy and past orogenesis:implications for conditions - deformation..Geology, Vol. 26, No. 7, July pp. 639-642.Colorado, WyomingLaramide Orogeny, deformation, Mantle
DS2002-0790
2002
Jones, C.H.Jones, C.H.User - driven integrated software lives: "paleomag".. paleomagnetics analysis on the MacIntosh.Computers and Geosciences, Vol. 28, 10, pp.1145-51.GlobalComputers - programs
DS2003-0669
2003
Jones, C.H.Jones, C.H.How faults accommodate plate motionScience, No. 5622, May 16, pp. 1105-6.MantleTectonics
DS200412-0194
2004
Jones, C.H.Boyd, O.S., Jones, C.H., Sheehan, A.F.Foundering lithosphere imaged beneath the Southern Sierra Nevada, California.Science, No. 5684, July 30, p. 660-662.United States, CaliforniaGeophysics - MT
DS200412-0928
2003
Jones, C.H.Jones, C.H.How faults accommodate plate motion.Science, No. 5622, May 16, pp. 1105-6.MantleTectonics
DS200412-1352
2004
Jones, C.H.Molnar, P.,Jones, C.H.A test laboratory based rheological parameters of olivine from an analysis of late Cenozoic convective removal of mantle lithospGeophysical Journal International, Vol. 156, 3, pp. 555-564.United States, CaliforniaMantle - slab
DS200512-0201
2004
Jones, C.L.Dahl, P.S., Hamilton, M.A., Wooden, J.L., Tracy, R.J., Loehn, C.W., Jones, C.L., Foland, K.A.Do 2450-2480 mineral ages from Wyoming cratonic margins (USA) indicate incipient breakup of supercontinet Kenorland?Geological Society of America Annual Meeting ABSTRACTS, Nov. 7-10, Paper 142-8, Vol. 36, 5, p. 340.United States, WyomingGeochronology
DS1975-1090
1979
Jones, C.R.Jones, C.R.The Reconnaissance Airborne Magnetic Survey of Botswana. Background and Follow-up.Botswana Geological Survey, Bulletin. No. 22, PP. 1-30.BotswanaGeophysics, Regional
DS1991-0807
1991
Jones, D.Jones, D.Ghostly graphiteNature, Vol. 351, June 13, p. 526GlobalGraphite, DREADCO
DS1992-0805
1992
Jones, D.Jones, D.Pinched diamonds.. diamond fibres by DaedalusNature, Vol. 356, No. 6367, March 26, p. 286GlobalNews item, Diamond fibres
DS202012-2223
2020
Jones, D.C.Jones, D.C., Kumar, S., Lanigan, P.M.P., McGuiness, C.D., Dale, M.W., Twichen, D.J., Fisher, D., Martineau, P.M., Neil, M.A., Dunsby, C., French, P.M.W.Multidemensional luminescence microscope for imaging defect colour centres in diamond.Methods and Applications in Flouresence, Vol. 8, 1, 01404 htpp:dx.doi.org/10.1088/2050-6120/ab4eacGloballuminescence

Abstract: We report a multidimensional luminescence microscope providing hyperspectral imaging and time-resolved (luminescence lifetime) imaging for the study of luminescent diamond defects. The instrument includes crossed-polariser white light transmission microscopy to reveal any birefringence that would indicate strain in the diamond lattice. We demonstrate the application of this new instrument to detect defects in natural and synthetic diamonds including N3, nitrogen and silicon vacancies. Hyperspectral imaging provides contrast that is not apparent in conventional intensity images and the luminescence lifetime provides further contrast.
DS1997-0259
1997
Jones, D.G.De Meijer, R.J., Stapel, C., Jones, D.G., Roberts..Improved and new uses of natural radiactivity n mineral exploration andprocessingExploration and Mining Geology, Vol. 6, No. 1, pp. 105-117GlobalCoast - sediments, heavy minerals, Technology - radioactivity
DS201912-2784
2019
Jones, D.G.Gilfillan, S.M.V., Gyore, D., Flude, S., Johnson, G., Bond, C.E., Hicks, N., Lister, R., Jones, D.G., Kremer, Y., Hazeldine, R.S., Stuart, F.M.Noble gases confirm plume related mantle degassing beneath southern Africa.Nature Communications, Vol. 10, 1, 10.1038/s41467-019-1244-6Africa, South Africaplumes

Abstract: Southern Africa is characterised by unusually elevated topography and abnormal heat flow. This can be explained by thermal perturbation of the mantle, but the origin of this is unclear. Geophysics has not detected a thermal anomaly in the upper mantle and there is no geochemical evidence of an asthenosphere mantle contribution to the Cenozoic volcanic record of the region. Here we show that natural CO2 seeps along the Ntlakwe-Bongwan fault within KwaZulu-Natal, South Africa, have C-He isotope systematics that support an origin from degassing mantle melts. Neon isotopes indicate that the melts originate from a deep mantle source that is similar to the mantle plume beneath Réunion, rather than the convecting upper mantle or sub-continental lithosphere. This confirms the existence of the Quathlamba mantle plume and importantly provides the first evidence in support of upwelling deep mantle beneath Southern Africa, helping to explain the regions elevation and abnormal heat flow.
DS1960-0685
1966
Jones, D.L.Jones, D.L.Paleomagnetism of the Premier Mine KimberliteJournal of Geophysical Research, Vol. 73, No. 22, PP. 6937-6944.South AfricaKimberlite, Geophysics
DS1960-0686
1966
Jones, D.L.Jones, D.L., Mcelhinney, M.W.Paleomagnetic Correlation of Basic Intrusions in the Precambrian of Southern Africa.Journal of Geophysical Research, Vol. 71, No. 2, PP. 543-552.South AfricaRelated Rocks, Paleomagnetics
DS1960-0847
1967
Jones, D.L.Jones, D.L., Walford, M.E.R., Gifford, A.C.A Paleomagnetic Result from the Ventersdorp Lavas of South Africa.Earth and Planetary Science Letters, Vol. 2, No. 3, PP. 155-158.South AfricaDe Beers Mine, Paleomagnetics
DS1970-0880
1974
Jones, D.L.Blake, M.C., Jones, D.L.Origin of Franciscan Melanges in Northern CaliforniaSoc. Econ. Paleontologists And Mineralogists Spec. Publishing, No. 19, PP. 345-357.CaliforniaKimberlite
DS1975-0568
1977
Jones, D.L.Mcfadden, P.L., Jones, D.L.The Paleomagnetism of Some Upper Cretaceous Kimberlite Occurrences in South Africa.Earth and Planetary Science Letters, Vol. 34, No. 1, PP. 125-135.South AfricaKimberlite, Geophysics
DS1990-1125
1990
Jones, D.L.Nyblade, A.A., Pollack, H.N., Jones, D.L., Podmore, F.Terrestrial heat flow in east and southern AfricaJournal of Geophysical Research, Vol. 95, No. B 11, October 10, pp. 17371-17384South AfricaHeat Flow, Mantle
DS1992-1404
1992
Jones, D.L.Silberling, N.J., Jones, D.L., Monger, J.W., Coney, P.J.Lithotectonic terrane map of the North American CordilleraUnited States Geological Survey (USGS) Map, No. I 2176 1- 80 miles $ 6.25GlobalLithotectonic map, Cordillera, Terranes
DS2001-0948
2001
Jones, D.L.Powell, C. McA., Jones, D.L., Pisarevsky, S., WingatePaleomagnetic constraints on the position of the Kalahari craton in RodiniaPrecambrian Research, Vol. 110, pp. 33-46.South Africa, Rodinia, GondwanaPaleomagetisM., Craton - Kalahari
DS201112-0410
2011
Jones, D.L.Hanson, R.E., Rioux, M., Gose, W.A., Blackburn, T.J., Bowring, S.A., Mukwakwami, J., Jones, D.L.Paleomagnetic and geochronological evidence for large scale post 1.88 Ga displacement between Zimbabwe and Kaapvaal Cratons along the Limpopo belt.Geology, Vol.39, 5, pp. 487-490.Africa, South Africa, ZimbabweGeochronology
DS1984-0385
1984
Jones, D.R.Jones, D.R.Difficulties Associated with Using Indicator Minerals for Diamond Exploration in North Queensland.Darwin Conference, Conference Series Australasian Institute Min., No. 13, PP. 127-139.Australia, QueenslandProspecting, Sampling, Techniques
DS1987-0322
1987
Jones, E.J.W.Jones, E.J.W.Fracture zones in the equatorial Atlantic and the breakup of westernPangeaGeology, Vol. 15, No. 6, June pp. 533-536Southern AfricaTectonics, Structure
DS1991-0808
1991
Jones, E.J.W.Jones, E.J.W., Goddard, D.A., Mitchell, J.G., Banner, F.T.Lamprophyric volcanism of Cenozoic age on the Sierra Leone rise-implications for regional tectonics and the stratigraphic time scaleMarine Geology, Vol. 99, No. 1-2, July pp. 19-28Sierra LeoneTectonics, Volcanics
DS1900-0330
1905
Jones, F.A.Jones, F.A.New Mexico Mines and MineralsNew Mexico Bureau of Immigration., 349P.United States, New Mexico, Rocky MountainsGemstones
DS1986-0515
1986
Jones, F.W.Majorowicz, J.A., Jones, F.W., Ertman, M.E., Linville, A., OsadetzHeat flow in the Edmonton-Cold Lake region Of the western Canadian sedimentary basin and the influence of fluid flowProceedings of the Third Canadian/American conference on hydro- geology, pp. 151-158. (Staff of Geological Society of Canada (GSC))AlbertaBasin, Geothermometry -heat flow
DS1987-0038
1987
Jones, F.W.Beach, R.D.W., Jones, F.W., Majorowicz, J.A.Heat flow and heat generation estimates for the Churchill basement of The western Canadian basin inAlberta, CanadaGeothermic, Vol. 16, No. 1, pp. 1-16AlbertaChurchill province, depth to basement, hot spots, Geothermometry
DS1988-0434
1988
Jones, F.W.Majorowicz, J.A., Jones, F.W., Osadetz, K.G.Heat flow environment of the electrical conductivity anomalies in the Williston Basin and occurrence ofhydrocarbonsCan. Soc. Pet. Geol. Bulletin, Vol. 36, No. 1, pp. 86-90AlbertaBasin, Geothermometry -heat flow
DS1996-0146
1996
Jones, F.W.Boerner, D., Kurtz, R., Craven, J., Jones, F.W.Electromagnetic results from the Alberta basement lithoprobe transectRoss, G.M. Lithoprobe Alberta, No. 51, pp. 61-70.AlbertaGeophysics - electromagnetic
DS1999-0342
1999
Jones, F.W.Jones, F.W., Pascal, F., Ertman, M.E.The generation and thermal and electromagnetic effects of rising melt in A three dimensional subducting modelDeep Electromagnetic Exploration, Springer, pp. 387-401.GlobalGeophysics - electromagnetic, Lithospheric slab model
DS1950-0024
1950
Jones, G.Foshag, W.F., Jones, G.The Diamond Industry in 1949Gems And Gemology, Vol. 6, No. 11, NOVEMBER PP. 341-343.United States, Canada, GlobalEconomics, Imports, Production
DS200912-0848
2009
Jones, G.Zaitsev, A.N., Keller, J., Jones, G., Grassineau, N.Mineralogical and geochemical changes of natrocarbonatites due to fumarolic activity at Oldoinyo Lengai volcano, Tanzania.alkaline09.narod.ru ENGLISH, May 10, 2p. abstractAfrica, TanzaniaCarbonatite
DS1985-0740
1985
Jones, G.C.Woolley, A.R., Jones, G.C.The Chilwa Alkaline Igneous Province, Malawi: Petrochemistry and Petrogenesis.Conference Report of The Meeting of The Volcanics Studies Gr, 1P. ABSTRACT.East Africa, MalawiEast African Rift, Tectonics, Geochemistry
DS1991-1891
1991
Jones, G.C.Woolley, A.R., Barr, M.W.C., Din, V.K., Jones, G.C., Wall, F.Extrusive carbonatites from the Uyaynah area, United Arab EmiratesJournal of Petrology, Vol. 32, pt. 6, pp. 1143-1167GlobalCarbonatite, Rock, mineral chemistry
DS200712-1216
2007
Jones, G.C.Zaitsev, A.N., Jones, G.C.Mineralogical and geochemical changes in natrocarbonatites due to fumarolic activity at Oldoinyo volcano, Tanzania.Frontiers in Mineral Sciences 2007, Joint Meeting of Mineralogical societies Held June 26-28, Cambridge, Abstract Volume p. 240.Africa, TanzaniaCarbonatite
DS200712-1217
2007
Jones, G.C.Zaitsev, A.N., Jones, G.C.Mineralogical and geochemical changes in natrocarbonatites due to fumarolic activity at Oldoinyo volcano, Tanzania.Frontiers in Mineral Sciences 2007, Joint Meeting of Mineralogical societies Held June 26-28, Cambridge, Abstract Volume p. 240.Africa, TanzaniaCarbonatite
DS1981-0225
1981
Jones, G.K.Jones, G.K.The Industrial Minerals of TanzaniaIndustrial Minerals, No. 166, JULY PP. 23-39.Tanzania, East AfricaDiamonds
DS1981-0312
1981
Jones, H.Nichols, I.A., Ferguson, J., Jones, H., Marks, G.P., Mutter, J.C.Ultramafic Blocks from the Ocean Floor Southwest of AustraliEarth and Planetary Science Letters, Vol. 56, PP. 362-374.Australia, Western AustraliaUltrabasic, Rocks, Lherzolite, Sea Floor Dredging
DS1993-0386
1993
Jones, H.Earnshow, R.A., Gigante, M.A., Jones, H.Virtual reality systemsAcademic Press, 327p. approx. $ 50.00GlobalBook -ad, Virtual reality systems
DS2001-0548
2001
Jones, H.G.Jones, H.G., Pomeroy, J.W., Walker, D.A., Hoham, R.W.Snow ecology: an inter disciplinary examination of snow-covered ecosystems. BOOK REVIEW Cambridge Univ. Press, 378p. @ 80.00 USGeoscience Canada, Vol.29,2, June pp. 89-90.CanadaBook - review, Snow ecosystem
DS1984-0428
1984
Jones, J.E.Kover, A.N., Jones, J.E., Southworth, C.S.Major Sources of New Radar Dat a for Exploration ResearchUnited States Geological Survey (USGS), pp. 833-61.AppalachiaRemote Sensing - Radar
DS1989-0723
1989
Jones, J.H.Jones, J.H.Boundary conditions for the Archean mantleLpi Technical Report, No. 89-05, pp. 50-52Hawaii, Australia, AlaskaMantle xenoliths, Inhomogeneous accretion M.
DS1996-1563
1996
Jones, J.H.Woronow, A., Reid, A.M., Jones, J.H.Parental magma compositions inferred from the chemical compositions of olivine controlled derivative meltsGeochimica et Cosmochimica Acta, Vol. 60, No. 4, Feb. 1, pp. 577-586GlobalMagma, Geochemistry
DS200712-0817
2006
Jones, K.Passas, N., Jones, K.Commodities and terrorist financing: focus on diamonds.European Journal on criminal policy and research., Vol. 12, 1, March pp. 1-33.GlobalConflict diamonds
DS2000-0305
2000
Jones, K.A.Friend, C.L., Jones, K.A., Burns, I.M.New high pressure granulite event in the Moine Supergroup, northern Scotland: implications Taconic...Geology, Vol. 28, No. 6, June pp. 543-6.ScotlandTectonics - Caledonian crustal evolution, high pressure
DS200512-0350
2004
Jones, L.E.Goleby, B.R., Blewett, R.S., Korsch, R.J., Champion, D.C., Cassidy, K.F., Jones, L.E., Groenewald, P.B., Henson, P.Deep seismic reflection profiling in the Archean northeastern Yilgarn Craton: implications for crustal architecture and mineral potential.Tectonophysics, Vol. 388, 1-4, pp. 119-133.AustraliaGeophysics - seismics, not specific to diamonds
DS1940-0010
1940
Jones, L.J.Jones, L.J.The Beryl or Diamond Fields LeadNew South Wales Geological Survey Mineral Resource., No. 38, PP. 64-66.AustraliaDiamond
DS1991-0313
1991
Jones, M.Cosgrove, J., Jones, M.Neotectonics and resourcesBelhaven Press, 450p. Cost?Costa Rica, Taiwan, Egypt, Papua New Guinea, JapanNeotectonics, Book -table of contents
DS1995-1776
1995
Jones, M.Smith, C.B., Green, R.W.E., Jones, M., Viljoen, K.S.Progress two ards understanding the evolution of the Kaapvaal lithosphere:the mantle perspective.Centennial Geocongress (1995) Extended abstracts, Vol. 1, p. 343-346. abstractSouth AfricaCraton, Mantle
DS1999-0343
1999
Jones, M.Jones, M.Next up to bat... Diavik diamond mineProspectors and Developers Association of Canada (PDAC) abstract volume, p. 7.Northwest TerritoriesMining, environment, Deposit - Diavik
DS1988-0334
1988
Jones, M.B.Jones, M.B., Von Frese, R.R.B.Correlative gravimetric and magnetic features of Ohio's basement rocksGeological Society of America (GSA) Abstract Volume, Vol. 20, No. 5, March p. 351. abstractGlobalBlank
DS202003-0367
2020
Jones, M.C.Turetsky, M.R., Abbott, B.W., Jones, M.C., Walter Anthony, K.. Olefeldt, D., Schuur, E.A.G., Grosse, G., Kuhry, P., Higelius, G., Koven, C., Lawrence, D.M., Gibson, C., Sannel, A.B.K., McGuire, A.D.Carbon release through abrupt permafrost thaw. ( not specific to diamonds but interest)Nature Geoscience, Vol. 13, pp. 138-143.Mantlecarbon

Abstract: The permafrost zone is expected to be a substantial carbon source to the atmosphere, yet large-scale models currently only simulate gradual changes in seasonally thawed soil. Abrupt thaw will probably occur in <20% of the permafrost zone but could affect half of permafrost carbon through collapsing ground, rapid erosion and landslides. Here, we synthesize the best available information and develop inventory models to simulate abrupt thaw impacts on permafrost carbon balance. Emissions across 2.5?million?km2 of abrupt thaw could provide a similar climate feedback as gradual thaw emissions from the entire 18?million?km2 permafrost region under the warming projection of Representative Concentration Pathway 8.5. While models forecast that gradual thaw may lead to net ecosystem carbon uptake under projections of Representative Concentration Pathway 4.5, abrupt thaw emissions are likely to offset this potential carbon sink. Active hillslope erosional features will occupy 3% of abrupt thaw terrain by 2300 but emit one-third of abrupt thaw carbon losses. Thaw lakes and wetlands are methane hot spots but their carbon release is partially offset by slowly regrowing vegetation. After considering abrupt thaw stabilization, lake drainage and soil carbon uptake by vegetation regrowth, we conclude that models considering only gradual permafrost thaw are substantially underestimating carbon emissions from thawing permafrost.
DS1975-0888
1978
Jones, M.D.Wagner, G.H., Honig, R.H., Jones, M.D.Geochemistry of a Carbonatite in Montgomery County, ArkansawArkansaw Academy of Science Proceedings, Vol. 32, PP. 93-94.United States, Gulf Coast, Arkansas, PennsylvaniaGeochemistry
DS1983-0338
1983
Jones, M.K.Jones, M.K., Fisher, R.W.Paleotectonics and Sedimentation in Sweetgrass Arch, MontanaAmerican Association of Petroleum Geologists Bulletin., Vol. 67, No. 8, P. 1344. (abstract.).United States, Montana, Rocky MountainsTectonics
DS1981-0226
1981
Jones, M.Q.W.Jones, M.Q.W.Heat Flow and Heat Production Studies in the Namaqua Mobile belt and the Kaapvaal Craton.Ph.d. Thesis, University of The Witwatersrand., 319P.South Africa, BotswanaGeothermometry, Regional Studies
DS1988-0335
1988
Jones, M.Q.W.Jones, M.Q.W.Heat flow in the Witwatersrand Basin and environs and its significance For the South African shield geotherm and lithosphere thicknessJournal of Geophysical Research, Vol. 93, No. B4, April 10, pp. 3243-3260South AfricaBlank
DS2001-0549
2001
Jones, M.Q.W.Jones, M.Q.W.Heat flow in southern Africa and thermal structure of the Kaapvaal lithosphere.Slave-Kaapvaal Workshop, Sept. Ottawa, 6p. abstractSouth AfricaGeothermometry, Heat flow, production, crustal thickness
DS1970-0729
1973
Jones, M.T.Jones, M.T.Brief Description of the Geology of Mochudi Area. Map Sheet2426a and 2426c.Botswana Geological Survey, (UNPUBL.)BotswanaKimberlite Occurrence, Morobe
DS1980-0147
1980
Jones, M.T.Green, D., Crockett, R.N., Jones, M.T.Tectonic Control of Karroo Sedimentation in Mid-eastern Botswana.Geological Society of South Africa Transactions, Vol. 83, PP. 213-219.BotswanaRegional Tectonics
DS2002-0566
2002
Jones, MQW.Gibson, R.L., Jones, MQW.Late Archean to Paleoproterozoic geotherms in the Kaapvaal Craton, South Africa: constraints on the thermal evolution of the Witwatersrand Basin.Basin Research, Vol.14,2, pp.169-82.South AfricaTectonics, Georthermometry
DS2003-0792
2003
Jones, N.L.Lemon, A.M., Jones, N.L.Building solid models from boreholes and user defined cross sectionsComputers and Geosciences, Vol. 29, 5, pp. 547-555.GlobalComputer - program not specific to diamonds
DS200412-1114
2003
Jones, N.L.Lemon, A.M., Jones, N.L.Building solid models from boreholes and user defined cross sections.Computers & Geosciences, Vol. 29, 5, pp. 547-555.TechnologyComputer - program not specific to diamonds
DS2000-0414
2000
Jones, P.Hogarth, D.D., Williams, C.T., Jones, P.Primary zoning in pyrochlore group minerals from carbonatitesMineralogical Magazine, Vol. 64, No. 4, Aug. 1, pp.675-83.GlobalCarbonatite
DS2003-0407
2003
Jones, P. C.Ferris, J.K., Storey, B.C., Vaughan, A.P.M., Kyle, P.R., Jones, P. C.The Dufek and Forrestal intrusions, Antarctica: a centre for Ferrar large igneousGeophysical Research Letters, Vol. 30, 6, p. 81 DOI 10.1029/2002GLO16719AntarcticaBlank
DS1993-1492
1993
Jones, P.C.Smyk, M.C., Taylor, R.P., Jones, P.C., Kingston, D.M.Geology and geochemistry of the West Dead Horse Creek rare-metaloccurrence, northwestern OntarioThe Canadian Institute of Mining, Metallurgy and Petroleum (CIM) Exploration and Mining Geology, Vol. 2, No. 3, July pp. 245-252OntarioGeochemistry, Diatreme breccia
DS200412-0551
2003
Jones, P.C.Ferris, J.K., Storey, B.C., Vaughan, A.P.M., Kyle, P.R., Jones, P.C.The Dufek and Forrestal intrusions, Antarctica: a centre for Ferrar large igneous province dike emplacement?Geophysical Research Letters, Vol. 30, 6, p. 81 DOI 10.1029/2002 GLO16719AntarcticaIgneous layered intrusions
DS1990-0776
1990
Jones, P.D.Jones, P.D., Wigley, T.M.L.Global warming trendsScientific American, Vol. 263, No. 2, August pp. 84-91GlobalGlobal climate, Future
DS1996-0699
1996
Jones, P.D.Jones, P.D.Climatic variations and forcing mechanisms of the last 2000 yearsSpringer Verlag Publ, 649p. $ 300.00 United StatesGlobalClimates, Book -ad
DS1981-0227
1981
Jones, P.R.Jones, P.R.El 652-orroroo Relinquishment ReportSouth Australia Open File., No. E 4162, 2P. UNPUBL.Australia, South AustraliaGeophysics, Geochemistry, Prospecting, Ground Magnetics, Soil Sampling
DS1981-0228
1981
Jones, P.R.Jones, P.R.El 486- Carrieton West, Stockdale Prospecting Limited Relinquishment Report.South Australia Open File., No. E4152, 1P. UNPUBL.Australia, South AustraliaStream Sediment Sampling, Geochemistry, Airborne Magnetics
DS1983-0339
1983
Jones, R.Jones, R., King, T.The Recursion Method and a First Principles Tight Binding Calculation of the Band Structures of Diamond and Silicon.Phil. Magazine., Vol. 47, No. 5, MAY, PP. 481-490.GlobalDiamond Mineralogy
DS1983-0340
1983
Jones, R.Jones, R., King, T.The Recursion Method. Application to Ideal and Reconstructed Vacancies in Diamond and Silicon.Phil. Magazine, Vol. 48, No. 4, OCTOBER, PP. 391-403.GlobalMineralogy
DS1983-0341
1983
Jones, R.Jones, R., King, T.E.G.Band Structures of Vacancies and Dislocations in DiamondJournal of PHYSICS (PARIS), Vol. 44, No. C-4, PP. C461-463.GlobalCrystallography
DS1984-0386
1984
Jones, R.Jones, R.Geochemical Evidence Bearing on the Origin of Southern African Kimberlitic Megacrysts and the Nature of Their Source Region.Geological Society of London NEWSLETTER., Vol. 13, No. 6, NOVEMBER (abstract.).South Africa, BotswanaGeochemistry
DS1988-0083
1988
Jones, R.Briddon, P., Jones, R., Lister, G.M.S.Hydrogen in diamondJournal of Phys. Cond.: Solid State Physics, Vol. 21, No. 30, pp. L1027-L1031GlobalDiamond morphology
DS1989-0477
1989
Jones, R.Gautam Sen, Jones, R.Experimental equilibration of multicomponent pyroxenes in the spinel peridotite field: implications for practical thermometers and a possiblebarometerJournal of Geophysical Research, Vol. 94, No. B 12, December 10, pp. 17, 871-17, 880GlobalExperimental petrology, Spinel-peridoite field
DS1991-0809
1991
Jones, R.Jones, R.River dimensions at Aredor mine, Guinea, West AfricaAlluvial Mining, held November 11-13, 1991, Institute of Mining and Metallurgy (IMM), GuineaAlluvial mining, Deposit -Aredor
DS1992-0806
1992
Jones, R.Jones, R.River diversions at Aredor, Guinea, West AfricaTransactions of the Institute of Mining and Metallurgy (IMM), Vol. 100, pp. A 115-A120GuineaAlluvial diamonds, Mining application
DS2003-0487
2003
Jones, R.Goss, J.P., Coomer, B.J., Jones, R., Fall, C.J., Briddon, P.R., Oberg, S.Extended defects in diamond: the interstitial plateletPhysical Review, Vol. 67, 16, 15p.GlobalBlank
DS200412-0700
2003
Jones, R.Goss, J.P., Coomer, B.J., Jones, R., Fall, C.J., Briddon, P.R., Oberg, S.Extended defects in diamond: the interstitial platelet.Physical Review Letters, Vol. 67, 16, 15p.TechnologyDiamond - morphology
DS200412-0967
2004
Jones, R.Keep, M., Longley, I., Jones, R.Sumba and its effect on Australia's northwestern margin.Hillis, R.R., Muller, R.D. Evolution and dynamics of the Australian Plate, Geological Society America Memoir, No. 372, pp. 309-318.AustraliaTectonics
DS200512-0355
2004
Jones, R.Goss, J.P., Briddon, P.R., Papagiannidis, S., Jones, R.Interstitial nitrogen and its complexes in diamond.Physical Review Letters, Vol. 70, 23, pp. 235208.Diamond inclusions
DS200612-0082
2006
Jones, R.Bangert, U., Barnes, R., Hounsome, L.S., Jones, R., Blumenau, A.T., Briddon, P.R., Shaw, M.J., Oberg, S.Electron energy loss spectroscopic studies of brown diamonds.Philosophical Magazine, Vol. 86, no. 29/31, pp. 4757-4780.TechnologyBrown diamonds
DS200612-0604
2006
Jones, R.Hounsome, L.S., Jones, R., Martineau, P.M., Fisher, D., Shaw, M.J., Briddon, P.R., Oberg, S.Origin of brown coloration in diamond.Physical Review Letters, Vol. 73, 12, pp. 125203 ( 8 pages)TechnologyDiamond - colour
DS200712-0051
2006
Jones, R.Bangert, U., Barnes, R., Hounsome, L.S., Jones, R., Bhumenau, A.T., Briddon, P.R., Shaw, M.J., Oberg, S.Electron energy loss spectroscopic studies of brown diamonds.Philosophical Magazine, Vol. 86, no. 29-31, pp. 4757-4779.TechnologyType IIa diamonds
DS1983-0141
1983
Jones, R.A.Boyd, F.R., Jones, R.A., Nixon, P.H.Mantle Metasomatism: the Kimberley Dunites #1Carnegie Institute Yearbook, FOR 1982, PP. 330-336.South AfricaKimberley, Kampfersdam, Bultfontein, De Beers, Mineral Chemistry
DS1984-0169
1984
Jones, R.A.Boyd, F.R., Jones, R.A., Nixon, P.H.Mantle Metasomatism: the Kimberley Dunites #2Geological Society of America (GSA), Vol. 16, No. 6, P. 453. (abstract.).South AfricaPetrography
DS1985-0315
1985
Jones, R.A.Jones, R.A., Boyd, F.R., Schulze, D.J.Glimmerite, Marid and Pkp Xenoliths from Kimberley Republic of South Africa.Geological Society of America (GSA), Vol. 17, No. 3, P. 163. (abstract.).South AfricaGeochemistry
DS1987-0323
1987
Jones, R.A.Jones, R.A.Strontium and neodynium isotopic and rare earth element evidence for the genesis of megacrysts in kimberlites of southern Africain: Nixon, P.H. ed. Mantle xenoliths, J. Wiley, pp. 711-724Southern AfricaBlank
DS1989-0724
1989
Jones, R.C.Jones, R.C.Unraveling origins, the Archean..Earth Science, Winter pp. 20-22.GlobalArchean - layman
DS1989-0725
1989
Jones, R.C.Jones, R.C., Stranges, A.N.Unravelling origins, the ArcheanEarth Science, ( layman's approach for interest), Winter 1989, pp. 20-22GlobalArchean, Overview -layman's interpretation
DS1988-0625
1988
Jones, R.E.Sen, G., Jones, R.E.Exsolved silicate and oxide phases from clinopyroxenes in a single Hawaiian xenolith: implications for oxidation state of the Hawaiian uppermantleGeology, Vol. 16, No. 1, January pp. 69-72HawaiiComparison with kimberlites, Analyses of clinopyroxene
DS2003-0137
2003
Jones, R.E.Bostick, B.C., Jones, R.E., Ernst, W.G., Chen, C., Leech, M.L., Beane, R.J.Low temperature microdiamond aggregates in the Maksyutov metamorphic complexAmerican Mineralogist, Vol. 88, pp. 1709-17.Russia, UralsGeochemistry
DS200412-0185
2003
Jones, R.E.Bostick, B.C., Jones, R.E., Ernst, W.G., Chen, C., Leech, M.L., Beane, R.J.Low temperature microdiamond aggregates in the Maksyutov metamorphic complex, South Ural Mountains, Russia.American Mineralogist, Vol. 88, pp. 1709-17.Russia, UralsGeochemistry
DS1982-0306
1982
Jones, R.N.Jones, R.N.Alluvial Diamond Mining Operation by Sierra Leone Selection trust Ltd.Camborne: Camborne School of Mines, Report Submitted For Min, Jan. 20TH. 38P.Sierra Leone, West AfricaAlluvial Diamond Placers, Mining Engineering, Plant, Equipment
DS200812-0170
2008
Jones, R.R.Butler, R.W.H., Bond, C.E., Shipton, Z.K., Jones, R.R., Casey, M.Fabric anisotropy controls faulting in the continental crust.Journal Geological Society of London, Vol. 165, 2, pp. 449-452.MantleAnisotropy
DS200512-0398
2004
Jones, S.Hanne, D., White, N., Butler, A., Jones, S.Phanerozoic vertical motions of Hudson Bay.Canadian Journal of Earth Sciences, Vol. 41, 10, Oct. pp. 1181-1200.Canada, Ontario, ManitobaTectonics
DS2001-0550
2001
Jones, S.M.Jones, S.M., White, N., Lovell, B.Cenozoic and Cretaceous transient uplift in the Porcupine Basin and its relationship to a mantle plume.Geological Society of London Special Publication, No. 187, pp. 345-60.OntarioTectonics, Plumes
DS2003-0670
2003
Jones, S.M.Jones, S.M.Test of a ridge plume interaction model using oceanic crustal structure around IcelandEarth and Planetary Science Letters, Vol. 208, 3-4, pp. 205-218.IcelandTectonics
DS2003-0671
2003
Jones, S.M.Jones, S.M., White, N.Shape and size of the starting Iceland plume swellEarth and Planetary Science Letters, Vol. 216, 3, pp. 271-82.IcelandHotspots
DS2003-0672
2003
Jones, S.M.Jones, S.M., White, N.Shape and size of the starting Iceland plume swellEarth and Planetary Science Letters, Vol. 216, 3, Nov. 30, pp. 271-282.IcelandBlank
DS200412-0929
2003
Jones, S.M.Jones, S.M.Test of a ridge plume interaction model using oceanic crustal structure around Iceland.Earth and Planetary Science Letters, Vol. 208, 3-4, pp. 205-218.Europe, IcelandTectonics
DS200412-0930
2003
Jones, S.M.Jones, S.M., White, N.Shape and size of the starting Iceland plume swell.Earth and Planetary Science Letters, Vol. 216, 3, pp. 271-82.Europe, IcelandHotspots
DS200612-0646
2005
Jones, S.M.Jones, S.M., Maclennan, J.Crustal flow beneath Iceland.Journal of Geophysical Research, Vol. 110, B9 B09410Europe, IcelandTectonics
DS201412-0759
2014
Jones, T.Russell, K., Brett, C., Jones, T., Andrews, G., Porritt, L.Kimberlite ascent.Goldschmidt Conference 2014, 1p. AbstractMantleKimberlite genesis
DS201708-1683
2017
Jones, T.Jones, T.Experimental milling of olivine: implications for ascent and eruption of kimberlite.11th. International Kimberlite Conference, OralMantleMineralogy - olivine
DS201708-1684
2017
Jones, T.Jones, T.Kimberlitic olivine attrition: fingerprinting environments and timescales.11th. International Kimberlite Conference, PosterMantleolivine
DS1990-0777
1990
Jones, T.A.Jones, T.A., Leonard, J.E.Why 3-D modeling?Nine articles on the subject - three dimensions. mostly applicable to petroleuM.Geobyte, Vol. 5, No. 1, pp. 25-49GlobalComputer -modeling, Graphics - 3 D.
DS1992-0898
1992
Jones, T.A.Krum, G.L., Jones, T.A.Pitfalls, in computer contouringGeobyte, Vol. 7, No. 3, pp. 30-35GlobalComputer, Computer contouring
DS1984-0387
1984
Jones, T.D.Jones, T.D., Nur, A.The Nature of Seismic Reflections from Deep Crustal Fault Zones.Journal of GEOPHYSICAL RESEARCH, Vol. B.89, No. 5, PP. 3153-3171.GlobalMid-continent
DS201602-0215
2016
Jones, T.D.Jones, T.D., Davies, D.R., Campbell, I.H., Wilson, C.R., Kramer, S.C.Do mantle plumes preserve the heterogeneous structure of their deep mantle source?Earth and Planetary Science Letters, Vol. 434, pp. 10-17.MantleTectonics

Abstract: It has been proposed that the spatial variations recorded in the geochemistry of hotspot lavas, such as the bilateral asymmetry recorded at Hawaii, can be directly mapped as the heterogeneous structure and composition of their deep-mantle source. This would imply that source-region heterogeneities are transported into, and preserved within, a plume conduit, as the plume rises from the deep-mantle to Earth's surface. Previous laboratory and numerical studies, which neglect density and rheological variations between different chemical components, support this view. However, in this paper, we demonstrate that this interpretation cannot be extended to distinct chemical domains that differ from surrounding mantle in their density and viscosity. By numerically simulating thermo-chemical mantle plumes across a broad parameter space, in 2-D and 3-D, we identify two conduit structures: (i) bilaterally asymmetric conduits, which occur exclusively for cases where the chemical effect on buoyancy is negligible, in which the spatial distribution of deep-mantle heterogeneities is preserved during plume ascent; and (ii) concentric conduits, which occur for all other cases, with dense material preferentially sampled within the conduit's centre. In the latter regime, the spatial distribution of geochemical domains in the lowermost mantle is not preserved during plume ascent. Our results imply that the heterogeneous structure and composition of Earth's lowermost mantle can only be mapped from geochemical observations at Earth's surface if chemical heterogeneity is a passive component of lowermost mantle dynamics (i.e. its effect on density is outweighed by, or is secondary to, the effect of temperature). The implications of our results for: (i) why oceanic crust should be the prevalent component of ocean island basalts; and (ii) how we interpret the geochemical evolution of Earth's deep-mantle are also discussed.
DS202006-0924
2020
Jones, T.D.Jones, T.D., Maguire, R.R., van Keken, P.E., Ritsema, J., Koelemeijer, P.Subducted oceanic crust as the origin of seismically slow lower-mantle structures.Progress in Earth and Planetary Science , Vol. 7, 16p. PdfMantlegeophysics - seismics

Abstract: Mantle tomography reveals the existence of two large low-shear-velocity provinces (LLSVPs) at the base of the mantle. We examine here the hypothesis that they are piles of oceanic crust that have steadily accumulated and warmed over billions of years. We use existing global geodynamic models in which dense oceanic crust forms at divergent plate boundaries and subducts at convergent ones. The model suite covers the predicted density range for oceanic crust over lower mantle conditions. To meaningfully compare our geodynamic models to tomographic structures, we convert them into models of seismic wavespeed and explicitly account for the limited resolving power of tomography. Our results demonstrate that long-term recycling of dense oceanic crust naturally leads to the formation of thermochemical piles with seismic characteristics similar to the LLSVPs. The extent to which oceanic crust contributes to the LLSVPs depends upon its density in the lower mantle for which accurate data is lacking. We find that the LLSVPs are not composed solely of oceanic crust. Rather, they are basalt rich at their base (bottom 100-200 km) and grade into peridotite toward their sides and top with the strength of their seismic signature arising from the dominant role of temperature. We conclude that recycling of oceanic crust, if sufficiently dense, has a strong influence on the thermal and chemical evolution of Earth’s mantle.
DS201806-1230
2018
Jones, T.J.Jones, T.J., Russell, J.K.Attrition in the kimberlite system. Olivine Mineralogy and Petrology, in press available, 11p.Mantlekimberlite ascent

Abstract: The sustained transportation of particles in a suspension commonly results in particle attrition leading to grain size reduction and shape modification. Particle attrition is a well-studied phenomenon that has mainly focussed on sediments produced in aeolian or fluvial environments. Here, we present analogue experiments designed to explore processes of attrition in the kimberlite system; we focus on olivine as it is the most abundant constituent of kimberlite. The attrition experiments on olivine use separate experimental set-ups to approximate two natural environments relevant to kimberlites. Tumbling mill experiments feature a low energy system supporting near continual particle-particle contact and are relevant to re-sedimentation and dispersal processes. Experiments performed in a fluidized particle bed constitute a substantially higher energy environment pertinent to kimberlite ascent and eruption. The run-products of each experiment are analysed for grain size reduction and shape modification and these data are used to elucidate the rates and extents of olivine attrition as a function of time and energy. Lastly, we model the two experimental datasets with an empirical rate equation that describes the production of daughter products (fines) with time. Both datasets approach a fines production limit, or plateau, at long particle residence times; the fluidized system is much more efficient producing a substantially higher fines content and reaches the plateau faster. Our experimental results and models provide a way to forensically examine a wide range of processes relevant to kimberlite on the basis of olivine size and shape properties.
DS201902-0318
2019
Jones, T.J.Sasse, D., Jones, T.J., Russell, K.Experimental milling of olivine: implications for ascent and eruption of kimberlite.AME Roundup, 1p. Abstract pp. 28-31.Mantlekimberlite genesis

Abstract: Kimberlite magmas entrain, transport and erupt large volumes of mantle-derived olivine grains. Characteristically, the olivine crystals found in kimberlite are rounded and ellipsoidal in shape. The origin of their ellipsoidal morphologies remains somewhat enigmatic given their origin from disaggregation of lithospheric mantle rocks. Explanations include rounding by magmatic corrosion and dissolution (Kamenetsky et al. 2008; Pilbeam et al. 2013) or mechanical milling (Arndt et al. 2006; Arndt et al. 2010; Russell et al. 2012; Jones et al. 2014; Brett et al. 2015). Here, we focus on mechanical processes that operate during turbulent mantle ascent, facilitating reshaping and resurfacing of olivine. During transport orthopyroxene and other mantle minerals are assimilated by the kimberlite magma. One effect of the assimilation is to raise the melt’s SiO2 content, thereby causing a reduction in CO2 solubility and the spontaneous exsolution of a CO2-dominated fluid phase (Brooker et al. 2011; Russell et al. 2012; Moussallam et al. 2015). This assimilation-driven exsolution of a fluid phase provides a continuous decrease in density, an increase in buoyancy, and an accelerating ascent. Additionally, there is strong evidence that, during kimberlite magma ascent through the mantle lithosphere, substantial mechanical modification of the suspended cargo occurs (Jones et al. 2014; Brett et al. 2015). Brett et al. (2015) hypothesized that the ascending dyke segregates into a turbulent gas-rich head where particleparticle interactions dominate followed by a trailing tail of less gas-charged magma. This ascending dyke continually modifies its cargo from initial disaggregation to ultimately, eruption. Here, we present data from a series of novel, scaled, analogue attrition experiments that inform on the rates, efficiency and timings of mechanical modification possible during transport through the mantle lithosphere.
DS201907-1554
2019
Jones, T.J.Jones, T.J., Russell, J.K., Sasse, D.Modification of mantle cargo by turbulent ascent of kimberlite.Frontiers in Earth Science, Vol. 7, pp. 134-145. pdfGlobalkimberlite genesis

Abstract: Kimberlite magmas transport cratonic mantle xenoliths and diamonds to the Earth's surface. However, the mechanisms supporting the successful and efficient ascent of these cargo-laden magmas remains enigmatic due to the absence of historic eruptions, uncertainties in melt composition, and questions concerning their rheology. Mantle-derived xenocrystic olivine is the most abundant component in kimberlite and is uniquely rounded and ellipsoidal in shape. Here, we present data from a series of attrition experiments designed to inform on the transport of low-viscosity melts through the mantle lithosphere. The experimental data suggest that the textural properties of the mantle-derived olivine are records of the flow regime, particle concentration, and transport duration of ascent for kimberlitic magmas. Specifically, our results provide evidence for the rapid and turbulent ascent of kimberlite during their transit through the lithosphere; this transport regime creates mechanical particle-particle interactions that, in combination with chemical processes, continually modify the mantle cargo and facilitate mineral assimilation.
DS202001-0022
2019
Jones, T.J.Jones, T.J., Reynolds, C.D., Boothroyd, S.C.Fluid dynamic induced break-up during volcanic eruptions. ( mentions kimberlite and carbonatite)Nature Communications, doi.org/10.1038/ s41467-019-11750-4 7p. pdf Mantlemelting

Abstract: Determining whether magma fragments during eruption remains a seminal challenge in volcanology. There is a robust paradigm for fragmentation of high viscosity, silicic magmas, however little is known about the fragmentation behaviour of lower viscosity systems—the most abundant form of volcanism on Earth and on other planetary bodies and satellites. Here we provide a quantitative model, based on experiments, for the non-brittle, fluid dynamic induced fragmentation of low viscosity melts. We define the conditions under which extensional thinning or liquid break-up can be expected. We show that break-up, both in our experiments and natural eruptions, occurs by both viscous and capillary instabilities operating on contrasting timescales. These timescales are used to produce a universal break-up criterion valid for low viscosity melts such as basalt, kimberlite and carbonatite. Lastly, we relate these break-up instabilities to changes in eruptive behaviour, the associated natural hazard and ultimately the deposits formed.
DS202007-1144
2020
Jones, T.J.Haddock, D., Manya, S., Brown, R.J., Jones, T.J., Wadsworth, F.B., Dobson, K.J., Gernon, T.M.Syn-eruptive agglutination of kimberlite volcanic ash. PyroclastsVolcanica, Vol. 3, 1, pp. 169-182. PdfAfrica, Tanzaniadeposit - Igwisi Hills

Abstract: Pyroclastic deposits of the Holocene Igwisi Hills kimberlite volcanoes, Tanzania, preserve unequivocal evidence for rapid, syn-eruptive agglutination. The unusual pyroclasts are composed of ash-sized particles agglutinated to each other by thin necks. The textures suggest the magma was disrupted into droplets during ascent. Collisions between particles occurred within a volcanic plume and on deposition within the conduit to form a weakly agglutinated, porous pyroclastic deposit. Theoretical considerations indicate that agglutination occurred over short timescales. Agglutinated clasts were entrained into weak volcanic plumes and deposited around the craters. Our results support the notion that agglutination can occur during kimberlite eruptions, and that some coherent, dense rocks in ancient kimberlite pipes interpreted as intrusive rocks could instead represent agglutinated pyroclastic rocks. Differentiating between agglutinated pyroclastic rocks and effusive or intrusive rocks in kimberlite pipes is important because of the potential effects that pyroclastic processes might have on diamond concentrations in deposits.
DS202007-1151
2019
Jones, T.J.Jones, T.J., Reynolds, C.D., Boothroyd, S.C.Fluid dynamics induced break up during volcanic eruptions.Nature Communications, Vol. 10, 1, 10.1038/s41467-019-11750-4.Mantlegeodynamics

Abstract: Determining whether magma fragments during eruption remains a seminal challenge in volcanology. There is a robust paradigm for fragmentation of high viscosity, silicic magmas, however little is known about the fragmentation behaviour of lower viscosity systems—the most abundant form of volcanism on Earth and on other planetary bodies and satellites. Here we provide a quantitative model, based on experiments, for the non-brittle, fluid dynamic induced fragmentation of low viscosity melts. We define the conditions under which extensional thinning or liquid break-up can be expected. We show that break-up, both in our experiments and natural eruptions, occurs by both viscous and capillary instabilities operating on contrasting timescales. These timescales are used to produce a universal break-up criterion valid for low viscosity melts such as basalt, kimberlite and carbonatite. Lastly, we relate these break-up instabilities to changes in eruptive behaviour, the associated natural hazard and ultimately the deposits formed.
DS202009-1656
2020
Jones, T.J.Sasse, D., Jones, T.J., Russell, J.K.Transport, survival and modification of xenoliths and xenocrysts from source to surface.Earth and Planetary Science Letters, Vol. 548, 12p. PdfMantlekimberlite ascent

Abstract: A wide variety of magmas entrain, transport and erupt mantle material in the form of xenoliths and xenocrysts. The host magmas are often low viscosity in nature and range from basalt to more esoteric compositions such as kimberlite, nephelinite and basanite. Here we focus on kimberlite magmas which are particularly successful at transporting deep mantle cargo to the surface, including economically important quantities of diamond. Collections of mantle-derived xenoliths and xenocrysts are critical to our understanding of the structure, stability, composition, thermal state, age, and origin of the lithosphere. However, they also inform on magma transport conditions. Through a series of scaled analogue experiments, we document the relative mechanical stability of olivine, garnet, orthopyroxene, clinopyroxene and diamond xenocrysts during magma ascent. Our experiments fluidized these mantle minerals at a constant gas flux for variable amounts of time approximating transport in a high velocity, turbulent, fluid-rich (supercritical fluid or gas, depending on depth) magma. The evolution of mineral surface features, morphology and grain size distributions is analyzed as a function of residence time. We show that on timescales consistent with magma ascent, each mantle mineral is subject to mechanical modification resulting in mass loss and reshaping (rounding) by grain size reduction and surface pitting. We further discuss the chemical consequences of producing fine particle chips that are highly susceptible to dissolution. Lastly, we utilize an empirical model that relates textural observations (e.g. impact pit size) on xenocrysts to differential particle velocities. Our approach applied to natural kimberlitic olivine and garnet xenocrysts indicates differential velocities of - the first direct estimate for velocity in an ascending kimberlite magma.
DS202011-2040
2020
Jones, T.J.Haddock, D., Manya, S., Brown, R.J., Jones, T.J., Wadsworth, F.B., Dobson, K.J., Gernon, T.M.Syn-eruptive agglutination of kimberlite volcanic ash.Volcanica, 15p. PdfAfrica, Tanzaniadeposit - Igwisi Hills kimberlite

Abstract: Pyroclastic deposits of the Holocene Igwisi Hills kimberlite volcanoes, Tanzania, preserve unequivocal evidence for rapid, syn-eruptive agglutination. The unusual pyroclasts are composed of ash-sized particles agglutinated to each other by thin necks. The textures suggest the magma was disrupted into droplets during ascent. Collisions between particles occurred within a volcanic plume and on deposition within the conduit to form a weakly agglutinated, porous pyroclastic deposit. Theoretical considerations indicate that agglutination occurred over short timescales. Agglutinated clasts were entrained into weak volcanic plumes and deposited around the craters. Our results support the notion that agglutination can occur during kimberlite eruptions, and that some coherent, dense rocks in ancient kimberlite pipes interpreted as intrusive rocks could instead represent agglutinated pyroclastic rocks. Differentiating between agglutinated pyroclastic rocks and effusive or intrusive rocks in kimberlite pipes is important because of the potential effects that pyroclastic processes might have on diamond concentrations in deposits.
DS202205-0690
2022
Jones, T.J.Jones, T.J., Russell, J.K., Brown, R.J., Hollendonner, L.Melt stripping and agglutination of pyroclasts during the explosive eruption of low viscosity magmas.Nature Communications, 10.1038/s41467-022-28633-w 12p. PdfMantlemagmatism

Abstract: Volcanism on Earth and on other planets and satellites is dominated by the eruption of low viscosity magmas. During explosive eruption, high melt temperatures and the inherent low viscosity of the fluidal pyroclasts allow for substantial post-fragmentation modification during transport obscuring the record of primary, magmatic fragmentation processes. Here, we show these syn-eruption modifications, in the form of melt stripping and agglutination, to be advantageous for providing fundamental insights into lava fountain and jet dynamics, including eruption velocities, grain size distributions and melt physical properties. We show how enigmatic, complex pyroclasts termed pelletal lapilli form by a two-stage process operating above the magmatic fragmentation surface. Melt stripping from pyroclast surfaces creates a spray of fine melt droplets whilst sustained transport in the fountain allows for agglutination and droplet scavenging, thereby coarsening the grain size distribution. We conclude with a set of universal regime diagrams, applicable for all fluidal fountain products, that link fundamental physical processes to eruption conditions and melt physical properties.
DS1860-0148
1871
Jones, T.R.Jones, T.R.On the Diamond Fields of South Africa Orange and Vaal riversGeology Magazine (London), Dec. 1, Vol. 8, PP. 49-60.Africa, South Africa, Cape ProvinceGeology
DS1860-0149
1871
Jones, T.R.Jones, T.R.South Africa and Its Diamonds Orange and Vaal riversHertford: J. Tennant., 24P. ALSO: POPULAR SCIENCE SCIENCE, PP. 169-176.Africa, South Africa, Cape ProvinceGeology
DS1860-0150
1871
Jones, T.R.Jones, T.R.Crystalline Rocks from the Diamond Bearing Localities of The Orange and Vaal Valleys.Quarterly Journal of Geological Society (London), Vol. 27, PP. 50-51.Africa, South Africa, Cape ProvincePetrology, Alluvial Placers
DS1860-0441
1884
Jones, T.R.Jones, T.R.On the Geology of South Africa (1884)British Association Advanced Science Report, PP. 736-738. ALSO: NATURE Vol. 30, PP. 553-554.Africa, South AfricaRegional Geology
DS1860-0470
1885
Jones, T.R.Jones, T.R.South African Diamonds (1885)Popular Science Review., Vol. 10, P. 169. ALSO: SOC. ARTS Journal of, Vol. 23, P.Africa, South AfricaHistory
DS1860-0553
1887
Jones, T.R.Jones, T.R.Refuting Cape Diamonds as All Poor QualityRoy. Col. Institute, Vol. 18, APRIL 5 Proceedings PP. 216-233. DISC. PP. 233-251.Africa, South AfricaDiamond Morphology
DS1997-0107
1997
Jones, W.Boerner, D., Craven, J., Kurtz, R., Jones, W.Electrical structure in the Precambrian crust and mantle of westernCanada.Geological Survey of Canada Forum 1997 abstracts, p. 8. AbstractAlberta, SaskatchewanMantle, Geophysics - magnetotellurics
DS1985-0743
1985
Jones, W.B.Wright, J.B., Hastings, D.A., Jones, W.B., Williams, H.R.Geology and Mineral Resources of West AfricaAllen and Unwin Publ, 200pWest AfricaMineral Resources, Book -table Of Contents -listed Due To Interest
DS1990-0778
1990
Jones, W.B.Jones, W.B.The Buem volcanic and associated sedimentary rocks: Ghana a field and geochemical investigationJournal of African Earth Sciences, Vol. 11, No. 3/4, pp. 373-384GhanaVolcanics, Geochemistry
DS1983-0356
1983
Jones, W.J.Klasner, J.S., Jones, W.J.Geologic Interpretation of Gravity and Magnetic Dat a in Northern Michigan and Wisconsin.Geophysics, Vol. 48, No. 4, P. 451. (abstract.).MichiganMid-continent
DS1989-0791
1989
Jones, W.J.Klasner, J.S., Jones, W.J.Bouger gravity anomaly map and geologic interpretation of the Iron River 1X 2 quadrangle, Michigan and WisconsinUnited States Geological Survey (USGS) Map, No. I-1360-E, 1: 250, 000 $ 3.10Michigan, WisconsinMap, Bouguer gravity
DS1989-0726
1989
Jones-Cecil, M.Jones-Cecil, M., Crone, A.J.Constraints on the Anadarko Basin-Wichita Uplift boundary interpreted from aeromagnetic dataOklahoma Geological Survey, Circular - Anadarko Basin Symposium, held, No. 90, pp. 176-193GlobalTectonics, Geophysics -magnetics
DS201312-0461
2014
Jonnalagadda, M.K.Karmalkar, N.R., Duraiswami, R.A., Jonnalagadda, M.K., Griffin, W.L.Mid-Cretaceous lamproite from the Kutch region, Gujarat, India: genesis and tectonic implications.Gondwana Research, Vol. 26, 3-4, pp. 942-956.IndiaLamproite
DS201412-0444
2014
Jonnalagadda, M.K.Karmalkar, N.R., Duraiswami, R.A., Jonnalagadda, M.K., Griffin, W.L.Mid-Cretaceous lamproite from the Kutch region, Gujarat, NW India: genesis and tectonic implications.Gondwana Research, Vol. 26, 3-4, Nov. pp. 942-956.IndiaLamproite
DS200712-0494
2007
Jons, N.Jons, N., Schenk, V., Razakamanana, T.Polymetamorphic evolution of ultrahigh temperature granulites from southern Madagascar: implications for the amalgamation of Gondwana.Frontiers in Mineral Sciences 2007, Joint Meeting of Mineralogical societies Held June 26-28, Cambridge, Abstract Volume p. 256-257.Africa, MadagascarTectonics
DS200712-0495
2007
Jons, N.Jons, N., Schenk, V., Razakamanana, T.Polymetamorphic evolution of ultrahigh temperature granulites from southern Madagascar: implications for the amalgamation of Gondwana.Frontiers in Mineral Sciences 2007, Joint Meeting of Mineralogical societies Held June 26-28, Cambridge, Abstract Volume p. 256-257.Africa, MadagascarTectonics
DS200712-0944
2007
Jons, N.Schenk, V., Appel, P., Jons, N., Loose, D., Schumann, A., Wegner, H.Pan-African reworking of the northeastern corner of the Congo Craton in Uganda.Frontiers in Mineral Sciences 2007, Joint Meeting of Mineralogical societies Held June 26-28, Cambridge, Abstract Volume p. 257-258.Africa, UgandaTectonics
DS200712-0945
2007
Jons, N.Schenk, V., Appel, P., Jons, N., Loose, D., Schumann, A., Wegner, H.Pan-African reworking of the northeastern corner of the Congo Craton in Uganda.Frontiers in Mineral Sciences 2007, Joint Meeting of Mineralogical societies Held June 26-28, Cambridge, Abstract Volume p. 257-258.Africa, UgandaTectonics
DS202008-1376
2018
Jooste, V.Campbell, J.A.H., Jooste, V.The AK6 kimberlite - discovery through to production: learning the lessons of history.Botswana Journal of Earth Sciences, Vol. 7, pp. 13-28. pdfAfrica, Botswanadeposit - AK6

Abstract: The AK6 kimberlite in north-eastern Botswana, better known as Karowe, is today one of the world?s top diamond producers by value. Its potential, however, was not recognised when AK6 was first discovered some fifty years ago. This paper traces the history of Karowe from the discovery of AK6 through to evaluation and production, reflecting on the interplay of economic, technical and corporate elements and highlighting some of the lessons learnt along this journey. Karowe Mine has been operating since 2012 and is fully owned by Lucara Diamond Corporation. In 2015, Karowe yielded the second largest diamond ever found, the 1,109ct Lesedi La Rona (Fig. 1).
DS1998-0705
1998
JORC.JORC.Australian code for reporting of mineral resources and ore reserves ( the JORC code). Exposure draft July 30Jorc, Draft Proposal To Be Effective July 1999, July 30, 1998 16pAustraliaLegal - mineral reserves, reporting, Mineral resource, definition, classification
DS200912-0344
2009
Jordan, G.Jordan, G.Sustainable mineral resources management from regional mineral resources exploration to spatial contamination risk assessment of mining.Environmental Geology, Vol. 58, 1, pp. 153-169.GlobalResource - sustainability not specific to diamonds
DS2001-0979
2001
Jordan, M.Ritter, J.R.R., Jordan, M., Christensen, U.R., AchauerA mantle plume below the Eifel volcanic fields, GermanyEarth and Planetary Science Letters, Vol. 186, No. 1, pp. 7-14.GlobalTomography, Hot spot
DS1995-1974
1995
Jordan, R.E.Vandervoot, D.S., Jordan, R.E., Zeitler. P.K., Alonso, R.N.Chronology of internal drainage and uplift southern Puna plateau, Argentine central AndesGeology, Vol. 23, No. 2, Feb. pp. 145-148Andes, ArgentinaGeochronology, Tectonics
DS201811-2593
2018
Jordan, T.A.Martos, Y.M., Jordan, T.A., Catalan, M., Jordan, T.M., Bamber, J.L., Vaughan, D.G.Geothermal heat flux reveals the Iceland hotspot track underneath Greenland.Geophysical Research Letters, Vol. 45, 16, pp. 8214-8222.Europe, Greenlandplumes

Abstract: Heat escaping from the Earth's interior provides important clues about areas of geology and geodynamics. In addition, where a region is covered by an ice sheet, such as Greenland, variations in the heat supplied from the Earth's interior can potentially influence how the ice flows, and hence its future changes. Unfortunately, in ice covered regions direct measurements of heat flow are limited to sparse boreholes, meaning this important quantity is poorly understood. In this study we used variations in the Earth's magnetic field to map out the variations in the amount of heat being supplied to the base of the Greenland Ice Sheet from the Earth's interior. Ice sheet models incorporating these new and improved results will help better constrain future predictions of ice sheet evolution. Overall, the new map not only shows less extreme variations than previous studies, but also reveals a previously unseen band of warmer than expected rock stretching northwest to southeast across Greenland. This band, together with lithospheric models derived from gravity data, is interpreted to be the scar left as the Greenland tectonic plate moved over a region of hot upwelling mantle (the material beneath the tectonic plates), which now underlies Iceland.
DS1990-0474
1990
Jordan, T.E.Flemings, P.B., Jordan, T.E.Stratigraphic modeling of foreland basins: interpreting thrust deformation and lithosphere rheologyGeology, Vol. 18, No. 5, May pp. 430-434GlobalStructure, Foreland basins
DS1997-0021
1997
Jordan, T.E.Allmendinger, R.W., Jordan, T.E., Kay, S.M., Isacks, B.L.The evolution of the Altiplano-Puna Plateau of the Central AndesAnnual Review of Earth and Planetary Sciences, Vol. 25, pp. 139-174Andes, Bolivia, BrazilReview - plateau, Tectonics, stratigraphy
DS2001-0551
2001
Jordan, T.E.Jordan, T.E., Burns, Veiga, Pangaro. Copeland, MpodozisExtension and basin formation in the southern Andes caused by increased convergence rate: a mid-Cenozoic...Tectonics, Vol. 20, No. 3, June, pp. 308-24.AndesTectonics - not specific to diamonds
DS1980-0185
1980
Jordan, T.H.Jordan, T.H.Continents as a Chemical Boundary LayerPhilosphical Trans, Series A., Vol. 301, No. 1461, PP. 359-373.GlobalKimberlite
DS1992-0807
1992
Jordan, T.H.Jordan, T.H.Role of the continental tectosphere in the preservation of ArcheancratonsEos Transactions, Vol. 73, No. 14, April 7, supplement abstracts p. 323MantleCraton, Tectonics
DS1997-0935
1997
Jordan, T.H.Puster, P., Jordan, T.H.How stratified is mantle convection?Journal of Geophysical Research, Vol. 102, No. 4, April 10, pp. 7625-46.MantleConvection, Stratigraphy
DS1999-0233
1999
Jordan, T.H.Gaherty, J.B., Kato, M., Jordan, T.H.Seismological structure of the upper mantle: a regional comparison of seismic layering.Physical Earth and Planetary Interiors, Vol. 110, pp. 21-41.MantleGeophysics - seismics, Discontinuities
DS1999-0651
1999
Jordan, T.H.Shapiro, S.S., Hager, B.H., Jordan, T.H.Stability and dynamics of the continental tectosphereLithos, Vol. 48, No. 1-4, Sept. pp. 115-34.MantleGeodynamics, Craton
DS1999-0652
1999
Jordan, T.H.Shapiro, S.S., Hager, B.H., Jordan, T.H.The continental tectosphere and earth's long wave length gravity fieldLithos, Vol. 48, No. 1-4, Sept. pp. 135-52.MantleGeodynamics, Geophysics - gravity
DS2001-0336
2001
Jordan, T.H.Freybouger, M., Gaherty, J.B., Jordan, T.H.Structure of the Kaapvaal craton from surface wavesGeophysical Research Letters, Vol. 28, No. 13, July 1, pp. 2489-92.South AfricaTectonics, Geophysics - seismics
DS2002-0881
2002
Jordan, T.H.Korenaga, J., Jordan, T.H.On steady state heat flow and rheology of oceanic mantleGeophysical Research Letters, Vol. 29, 22, Nov. 15, DOI 10.1029/2002GLO16085MantleGeothermometry
DS2002-0882
2002
Jordan, T.H.Korenaga, J., Jordan, T.H.On the state of sublithospheric upper mantle beneath a supercontinentGeophysical Journal International, Vol.149,1,pp.179-89., Vol.149,1,pp.179-89.MantleBlank
DS2002-0883
2002
Jordan, T.H.Korenaga, J., Jordan, T.H.On the state of sublithospheric upper mantle beneath a supercontinentGeophysical Journal International, Vol.149,1,pp.179-89., Vol.149,1,pp.179-89.MantleBlank
DS2003-0743
2003
Jordan, T.H.Korenaga, J., Jordan, T.H.Physics of multiscale convection in Earth's mantle: onset of sublithospheric convectionJournal of Geophysical Research, Vol. 108, 2, 10.1029/2002JB001760MantleConvection
DS200412-1037
2003
Jordan, T.H.Korenaga, J., Jordan, T.H.Physics of multiscale convection in Earth's mantle: onset of sublithospheric convection.Journal of Geophysical Research, Vol. 108, 2, 10.1029/2002 JB001760MantleConvection
DS200412-1038
2004
Jordan, T.H.Korenaga, J., Jordan, T.H.Physics of multiscale convection in Earth's mantle: evolution of sublithospheric convection.Journal of Geophysical Research, Vol. 109, B1, 10.1029/2003 JB002464MantleGeophysics - seismics, convection
DS200512-0487
2004
Jordan, T.H.Jordan, T.H.Perspectives on continental evolution from xenoliths and geophysical data.Geological Society of America Annual Meeting ABSTRACTS, Nov. 7-10, Paper 17-2, Vol. 36, 5, p. 46.MantleIsopicnicity, tectonosphere, dyke swarms
DS200912-0647
2009
Jordan, T.H.Roy, M., Jordan, T.H., Pederson, J.Colorado Plateau magmatism and uplift by warming of heterogeneous lithosphere.Nature, Vol. 459, June pp. 978-985.United States, Colorado PlateauMagmatism
DS201811-2593
2018
Jordan, T.M.Martos, Y.M., Jordan, T.A., Catalan, M., Jordan, T.M., Bamber, J.L., Vaughan, D.G.Geothermal heat flux reveals the Iceland hotspot track underneath Greenland.Geophysical Research Letters, Vol. 45, 16, pp. 8214-8222.Europe, Greenlandplumes

Abstract: Heat escaping from the Earth's interior provides important clues about areas of geology and geodynamics. In addition, where a region is covered by an ice sheet, such as Greenland, variations in the heat supplied from the Earth's interior can potentially influence how the ice flows, and hence its future changes. Unfortunately, in ice covered regions direct measurements of heat flow are limited to sparse boreholes, meaning this important quantity is poorly understood. In this study we used variations in the Earth's magnetic field to map out the variations in the amount of heat being supplied to the base of the Greenland Ice Sheet from the Earth's interior. Ice sheet models incorporating these new and improved results will help better constrain future predictions of ice sheet evolution. Overall, the new map not only shows less extreme variations than previous studies, but also reveals a previously unseen band of warmer than expected rock stretching northwest to southeast across Greenland. This band, together with lithospheric models derived from gravity data, is interpreted to be the scar left as the Greenland tectonic plate moved over a region of hot upwelling mantle (the material beneath the tectonic plates), which now underlies Iceland.
DS2002-0462
2002
Jordan. T.E.Fisher, N.D., Jordan. T.E., Brown, L.The structural and stratigraphic evolution of the la Rioja basin, ArgentinaJournal of South American Earth Sciences, Vol.15,1,Apr.pp.141-56.Argentina, AndesTectonics
DS200512-0488
2005
Jordi, J.Jordi, J., Ammon, C.J., Nyblade, A.A.Evidence for mafic lower crust in Tanzania, East Africa, from joint inversion of receiver functions and Rayleigh wave dispersion velocities.Geophysical Journal International, Vol. 162, 2, August pp.555-569.Africa, TanzaniaGeophysics - seismics
DS200912-0278
2009
Jordi, J.Hansen, S.E., Nyblade, A.A., Jordi, J., Dirks, P.Upper mantle low velocity zone structure beneath the Kaapvaal craton from S wave receiver functions.Geophysical Journal International, Vol. 178, 2, pp. 1021-1027.Africa, South AfricaGeophysics - seismics
DS201012-0352
2009
Jordi, J.Kgaswane, E., Nyblade, A.A., Jordi, J., Durrheim, P.H.G.M., Raymond, J., Payanos, M.E.Shear wave velocity structure of the lower crust in southern Africa: evidence for compositional heterogeneity within Archean and Proterozoic terrains.Journal of Geophysical Research, Vol. 114, B12, B12304.AfricaGeophysics - seismics
DS201312-0449
2013
Jordi, J.Jordi, J., Nyblade, A.A.Probing the upper mantle transition zone under Africa with P520s conversions: implications for temperature and composition.Earth and Planetary Science Letters, Vol. 368, pp. 151-162.Africa, west AfricaDiscontinuity
DS1992-1003
1992
Jordt-Evangelista, H.Marshak, S., Alkmim, F.F., Jordt-Evangelista, H.Proterozoic crustal extension and the generation of dome and keel structure in an Archean granite-greenstone terraneNature, Vol. 357, No. 6378, June 11, pp. 491-493BrazilTectonics, Greenstone belts
DS2000-0457
2000
Jordt-Evangelista, H.Jordt-Evangelista, H., Macambira, M., Peres. G.G., Limalead/lead single zircon dating of Paleoproterozoic calc-alkaline /alkaline magmatism in Sao Francisco...Igc 30th. Brasil, Aug. abstract only 1p.Brazil, Minas GeraisCraton - southeastern border, Geochronology
DS1983-0181
1983
Jorge, M.I.B.Collins, A.T., Thomaz, M.F., Jorge, M.I.B.Luminescence Decay Time of the 1.945 Ev Centre in Type 1b DiamondJournal of Phys. Pt. C. Solid State Physics, Vol. 16, No. 11, pp. 2177-2181GlobalDiamond Morphology
DS1985-0479
1985
Jorge, M.I.B.Narae, M.H., Thomaz, M.F., Jorge, M.I.B.Luminescence Bands in Natural Brown DiamondsSolid State Communications, Vol. 55, No. 7, PP. 577-582.GlobalBlank
DS1986-0639
1986
Jorge, M.I.B.Pereira, M.E., Jorge, M.I.B., Thomaz, M.F.The red luminescence spectrum of brown diamonds- vibronic couplingJournal of Phys. C., Vol. 19, No. 7, March 10, pp. 1009-1015GlobalDiamond morphology
DS1989-0727
1989
Jorgensen, G.J.Jorgensen, G.J., Bosworth, W.Gravity modeling in the Central African Rift System,Sudan: rift geometries and tectonic significanceJournal of African Earth Sciences, Vol. 8, No. 2/3/4, pp. 283-306GlobalTectonics, Rifting -Sudan
DS2001-0552
2001
Jorgensen, J.O.Jorgensen, J.O., Holm, P.M.The role of carbonatites in the Cape Verde magmatism: lead, Strontium, and neodymium isotopic evidence of multiple sourcesJournal of South African Earth Sciences, Vol. 32, No. 1, p. A 20 (abs)GlobalCarbonatite, Geochronology
DS2001-0553
2001
Jorgensen, J.O.Jorgensen, J.O., Holm, P.M.A geochemical comparison of magnesiocarbonatites and co-existing suite of ocean island basalts ...Journal of South African Earth Sciences, Vol. 32, No. 1, p. A 20 (abs)GlobalCarbonatite, Sao Vicente Island
DS200512-0014
1998
Jorgensen, U.G.Andersen, A.C., Jorgensen, U.G., Nicolaisen, F.M., Sorensen, P.G., Glejbal, K.Spectral features of presolar diamonds in laboratory and in carbon star atmospheres.Astronomy and Astrophysics, Vol. 330, pp. 1080-1090.Meteorite
DS1986-0411
1986
Joris, A.Joris, A.A destiny in diamondsBoolarong Publishing Brisbane Queensland Australia, 113pAustraliaHistory
DS1986-0412
1986
Joris, A.Joris, A.Chapter 3, Copeton Adventuresin: A destiny in diamonds. Boolarong publications, pp. 15-26.Australia, New South WalesBlank
DS200412-0931
1986
Joris, A.Joris, A.Chapter 3, Copeton Adventures.in: A destiny in diamonds. Boolarong publications, pp. 15-26.Australia, New South WalesHistory
DS1983-0342
1983
Joris, A.C.T.Joris, A.C.T.Some Uncuttable Diamonds from New South WalesIndiaqua., No. 36, 1983/3, PP. 41-43.Australia, New South WalesDiamond Cutting, History, Copeton, Cudgegong
DS1930-0274
1938
Joris, J.Joris, J.Diamonds in Australia. #2Walkabout., P. 47.AustraliaDiamond
DS1900-0564
1907
Jorissen, E.Jorissen, E.Presidential Address - Gssa 1907Geological Society of South Africa Proceedings, Vol. 10, PP. XIX-XXXI.Africa, South AfricaDiamond, Kimberlite
DS1998-0998
1998
JoronMetrich, N., Joron, J-L, Berthier, B.Occurrence of boron rich potassic melts in the Vulsini volcanic district, Evidence from melt inclusions.Geochimica et Cosmochimica Acta, Vol. 62, No. 3, pp. 507-14.ItalyXenoliths
DS1985-0716
1985
Joron, J.L.Weaver, B.L., Wood, D.A., Tarney, J., Joron, J.L.Geochemical Nature of Mantle Sources of Atlantic Ocean Island Basalts.Conference Report of The Meeting of The Volcanics Studies Gr, 1P. ABSTRACT.GlobalIsotope, Petrography
DS1990-0203
1990
Joron, J.L.Bienvenu, P., Bougault, H., Joron, J.L., Treuil, M., Dmitriev, L.Mid Ocean Ridge Basalt (MORB) alteration: rare earth element/non-rare earth hydromagmaphile elementfractionationChemical Geology, Vol. 82, No. 1/2, March 30, pp. 1-14GlobalMagma genesis, Mid Ocean Ridge Basalt (MORB) alteration
DS1992-1014
1992
Joron, J-L.Maury, R.C., Defant, M.J., Joron, J-L.Metasomatism of the sub-arc mantle inferred from trace elements in Philippine xenolithsNature, Vol. 360, Dece, ber 17, pp. 661-663PhilippinesXenoliths, Mantle
DS1993-1388
1993
Joron, J-L.Schiano, P., Algre, C.J., Dupre, B., Lewin, E., Joron, J-L.Variability of trace elements in basaltic suitesEarth and Planetary Science Letters, Vol. 119, No. 1-2, August pp. 37-52GlobalGeochemistry, Basalt
DS200712-0402
2007
Joron, J-L.Halama, R., Joron, J-L., Villemant, B., Markl, G., Treuil, M.Trace element constraints on mantle sources during mid-Proterozoic magmatism: evidence for a link between Gardar and Abitibi mafic rocks.Canadian Journal of Earth Sciences, Vol. 44, 4, pp. 459-478.Canada, Quebec, Europe, GreenlandMagmatism
DS1990-0779
1990
Josenhans, H.W.Josenhans, H.W., Zevenhuizen, J.Dynamics of the Laurentide ice sheet in Hudson Bay, CanadaMarine Geology, Vol. 92, No. 1-2, pp. 1-26OntarioGeomorphology, Laurentide Ice Sheet
DS2003-0673
2003
Joseph, E.J.Joseph, E.J., Segawa, J., Kusumoto, S., Nakayama, E., Ishihara, T., KomazawaAirborne gravimetry - a new gravimeter system and test resultsExploration Geophysics, Vol. 34, 1-2, pp. 82-86.GlobalGeophysics - gravimetry not specific to diamonds
DS200412-0932
2003
Joseph, E.J.Joseph, E.J., Segawa, J., Kusumoto, S., Nakayama, E., Ishihara, T., Komazawa, M., Sakuma, S.Airborne gravimetry - a new gravimeter system and test results.Exploration Geophysics, Vol. 34, 1-2, pp. 82-86.TechnologyGeophysics - gravimetry not specific to diamonds
DS1994-1425
1994
Joseph, M.Radhakrishna, T., Dallmeyer, R.D., Joseph, M.Paleomagnetism and 36 Ar-40 Ar vs 39 Ar-40 Ar isotope correlation ages of dyke swarms in central Kerala, India: tectonic implications.Earth and Planetary Science Letters, Vol. 121, No. 1/2, January pp. 213-226.IndiaDikes, isotope correlation, Argon, Tectonics
DS1994-1426
1994
Joseph, M.Radhakrishna, T., Dallmeyer, R.D., Joseph, M.Paleomagnetism and 36 Ar-40Ar vs 39Ar-40r isotope correlation ages of dyke swarms in central Kerala, India: tectonic implications.Earth and Planetary Science Letters, Vol. 121, pp. 213-226.IndiaPaleomagnetics, Argon, Dykes
DS1998-1201
1998
Joseph, M.Radhakrishna, T., Joseph, M.Geochemistry and petrogenesis of the Proterozoic dikes in Tamil Nadu:another example of Archean lithosphericGeol. Rundsch., Vol. 87, No. 3, Dec. pp. 268-82.India, southern IndiaDike - mantle source
DS2003-1122
2003
Joseph, M.Radhakrishna, T., Joseph, M., Krishnendu, N.R., Balasubramonian, G.Paleomagnetism of mafic dykes in Dharwar Craton: possible geodynamic implicationsGeological Society of India Memoir, No. 50, pp. 193-224.IndiaGeophysics - magnetics
DS200412-1608
2003
Joseph, M.Radhakrishna, T., Joseph, M., Krishnendu, N.R., Balasubramonian, G.Paleomagnetism of mafic dykes in Dharwar Craton: possible geodynamic implications.Geological Society of India Memoir, No. 50, pp. 193-224.IndiaGeophysics - magnetics
DS201012-0761
2009
Josey, S.D.Stott, G.M., Josey, S.D.Regional geology and mineral deposits of northern Ontario, north of latitude 49 30.Ontario Geological Survey, Open file 6242 and Data set 265, 1 DVD $ 25.00Canada, OntarioInventory of records on file
DS202102-0200
2020
Joshi, K.B.Joshi, K.B., Sorcar, N., Pant, N.C., Nandakumar, V., Ahmad, T., Tomson, J.K.Characterization of multiple episodes of melt generation from lower crust during Archean using amphibole composition.Episodes, doi.org/10.18814/ epiiugs/2020 /020092 24p. PdfIndiaCraton - Bundelkhand

Abstract: Spatial association of tonalite trondhjemite granodiorites (TTGs) and high-K granitoids (anatectic and hybrid granites) from the Bundelkhand Craton (BC), Central India, is well known. Geochronological data indicates multiple episodes of formation of these high silica rocks showing a spread of ~1 Ga during Paleo to Neoarchaean. In the present study, we try to understand the evolution of TTGs and high-K granitoids (hybrid granites) from the BC using amphibole composition. The amphibole in both TTGs and high-K granitoids (hybrid granites) from the BC are characterised as magmatic, zoned, and calcic in nature. We find that the amphibole composition of the studied rocks is dominated by magnesiohornblende along with less common occurrence of tschermakite, magnesiohastingsite and edenite. Overall variation in amphibole compositions in terms of exchange vectors show a well defined linear trend (except for a late stage low-grade metamorphic readjustment), which suggests melt control over crystallization and evolution of amphibole chemistry. Moreover, the geothermobarometric analysis points towards higher pressure formation of TTGs in comparison to that of high-K granitoids (hybrid granites), with nearly the same temperature conditions in both the cases. Combining all our findings, we propose the evolution of the two considered rock types through lower crustal melting under varying PH2O conditions at different depths of emplacement.
DS202106-0945
2021
Joshi, K.B.Joshi, K.B., Goswami, V., Bannerji, U.S., Shankar, R.Recent developments in instrumentation and its application in absolute dating: historical perspective and overview.** not specific to diamondsJournal of Asian Earth Sciences, Vol. 211, 104690, 23p. PdfGlobalradiometric dating

Abstract: The discovery of radioactivity in the early 20th century led to the development of several radiometric dating methods (e.g., Rb-Sr, Sm-Nd, Re-Os, U-Pb, etc.). These radiometric dating methods are frequently used in earth science studies to constrain the deposition/formation timing of various natural archives (e.g., bulk rocks, minerals, carbonaceous materials, detrital clastic sedimentary materials, ore deposits, hydrocarbon deposits). The last few decades have witnessed significant improvements in overall accuracy and precision of these absolute radiometric dating methods due to continuous developments and refinements in sample processing and analytical techniques. In this contribution, we discuss some of the frequently used radiometric dating techniques for obtaining absolute ages in various natural archives and associated advancements in the instrumentation. The present attempt emphasizes on a multi-mineral and multi-isotopic approach with continuous developments in obtaining better precision and accuracy in the ages through improved analytical and measurement protocols that are the pre-requisite in absolute dating.
DS1993-1587
1993
Joshi, M.S.Thakur, N.K., Nagarajan, N., Joshi, M.S.Estimation of the regional Bouguer gravity field over the Indian Peninsula using two dimensional filtering.Tectonophysics, Vol. 225, pp. 543-550.IndiaGeophysics -gravity
DS1991-0517
1991
Joshi, S.D.Fritz, R.D., Horn, M.K., Joshi, S.D.Geological aspects of horizontal drillingAmerican Association of Petroleum Geol. Bulletin, No. 33, 563p. approx. $ 45.00 United StatesGlobalDrilling -petroleuM., Book -ad
DS201312-0450
2013
Joshi, V.Joshi, V.Has India's moment come and gone? Growth has slowed…. Optima, Dec. pp. 20-29.IndiaEconomics
DS200512-0492
2005
Jost, H.Junqueira-Brod, T.C., Gaspar, J-C., Brod, J.A., Jost, H., Rocha Barbosa, E.S., Kafino, C.V.Emplacement of kamafugitic lavas from the Goais alkaline province, Brazil: constraints from whole rock simulations. (mafurite, ugandite)Journal of South American Earth Sciences, Vol. 18, 3-4, March pp. 323-335.South America, BrazilSanto Antonio da Barra, Aguas Emendadas, carbonatite
DS1994-0852
1994
Joswiak, D.J.Joswiak, D.J., McCallum, I., Nelson, B.K.Age and geochemistry of lower crustal granulite xenoliths from minette dikes in central Montana.Geological Society of America (GSA) Abstract Volume, Vol. 26, No. 7, ABSTRACT only p. A296.MontanaIgneous petrology, Minette
DS1994-0959
1994
Joswiak, D.J.Kuehner, S.M., Joswiak, D.J.Ferric iron sanidine from the Leucite Hills Wyoming lamproites: diffraction characterization.Geological Society of America (GSA) Abstract Volume, Vol. 26, No. 7, ABSTRACT only p. A481.WyomingMineralogy, Lamproite, Leucite Hills
DS1996-0791
1996
Joswiak, D.J.Kuehner, S.M., Joswiak, D.J.Naturally occurring ferric iron sanidine from the Leucite Hills lamproiteAmerican Mineralogist, Vol. 81, No. 1-2, Jan-Feb. pp. 229-237.WyomingLamproite, Deposit -Leucite Hills
DS200512-0113
2005
JoswigBrenker, F.E., Vincze, L., Velemans, Nasdala, Stachel, Vollmer, Kersten, Somogyi, Adams, Joswig, HarrisDetection of a Ca rich lithology in the Earth's deep ( >300km) convecting mantle.Earth and Planetary Science Letters, Vol. 236, 3-4, pp. 579-587.Africa, GuineaKankan, diamond inclusions, spectroscopy
DS200712-0106
2007
JoswigBrenker, F.E., Vollmer, C., Vincze, L., Vekemans, B., Szymanski, Janssens, Szaloki, Nasdala, Joswig, KaminskyCarbonates from the lower part of transition zone or even the lower mantle.Earth and Planetary Science Letters, Vol. 260, 1-2, pp. 1-9.MantleCarbonates
DS200712-0107
2007
JoswigBrenker, F.E., Vollmer, C., Vincze, L., Vekemans, B., Szymanski, Janssens, Szaloki, Nasdala, Joswig, KaminskyCarbonates from the lower part of transition zone or even the lower mantle.Earth and Planetary Science Letters, Vol. 260, 1-2, pp. 1-9.MantleCarbonates
DS200712-0108
2007
JoswigBrenker, F.E., Vollmer, Vincze, Vekemans, Szymanski, Janssens, Szaloki, Nasdala, Joswig, KaminskyCarbonates from the lower part of transition zone or even the lower mantle.Earth and Planetary Science Letters, Vol. 260, 1-2, pp. 1-9.MantleCarbonates
DS2000-0923
2000
Joswig, W.Stachel, T., Harris, J.W., Joswig, W.Kankan diamonds II. Lower mantle inclusion paragenesesContributions to Mineralogy and Petrology, Vol. 140, No. 1, pp. 16-27.GuineaDiamond genesis, Deposit - Kankan
DS2002-0202
2002
Joswig, W.Brenker, F.E., Kaminsky, F., Joswig, W.Polytypes of CaSiO3 walstromite in diamonds from Juina: an indicator of retrograde reaction from CaSIO3 perovskite.18th. International Mineralogical Association Sept. 1-6, Edinburgh, abstract p.78. (poster)BrazilUHP mineralogy
DS200412-0933
1999
Joswig, W.Joswig, W., Stachel, T., Harris, J.W., Baur, W.H., Brey, G.P.New Ca silicate inclusions in diamonds - tracers from the lower mantle.Earth and Planetary Science Letters, Vol. 173, pp. 1-6.TechnologyDiamond inclusions
DS200612-0171
2006
Joswig, W.Brenker, F.E., Vollmer, C., Vincze, L., Vekemans, B., Szymanski, A., Janssens, K., Szaloki, I., Nasdala, L., Joswig, W., Kaminsky, F.CO2 recycling to the deep convecting mantle.Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 1, abstract only.MantleConvection
DS200712-0670
2007
Jouanna, P.Mainprice, D., Le Page, Y., Rodgers, J., Jouanna, P.Predicted elastic properties of hydrous D phase at mantle pressures: implications for the anisotropy of subducted slabs near 670 km discontinuity and in the lower mantle.Earth and Planetary Science Letters, Vol. 259, 3-4, pp. 283-296.MantleSubduction
DS200712-0671
2007
Jouanna, P.Mainprice, D., Le Page, Y., Rodgers, J., Jouanna, P.Predicted elastic properties of hydrous D phase at mantle pressures: implications for the anisotropy of subducted slabs near 670 km discontinuity and in the lower mantle.Earth and Planetary Science Letters, Vol. 259, 3-4, pp. 283-296.MantleSubduction
DS200412-1935
1984
Joubert, P.Stowe, C.W., Hartnady, C.J.H., Joubert, P.Proterozoic tectonic provinces of southern Africa.Precambrian Research, Vol. 25, 1-3, pp. 229-231.Africa, South AfricaTectonics
DS1920-0076
1921
Joubert, S.P.Joubert, S.P.Alluvial Diamond Diggers in South AfricaSouth African Journal of IND., Vol. 4, SEPT. PP. 702-712.South AfricaMineral Economics, Politics
DS2002-0924
2002
Jourdan, F.Le Gall, B., Tshoso, G., Jourdan, F., Feraud, G., Bertrand, H., Tiercelin, J.J.40 Ar/39 Ar geochronology and structural dat a from the giant Okavango and relatedEarth and Planetary Science Letters, Vol. 202, 3-4, pp. 595-606.BotswanaMagmatism - not specific to diamonds
DS200412-0934
2004
Jourdan, F.Jourdan, F., Feraud, Bertrand, Kampunzu, Watkeys, Le Gall, TshosoNew age constraints on the Karoo Large Igneous Province: triple junction and brevity questioned.Geochimica et Cosmochimica Acta, 13th Goldschmidt Conference held Copenhagen Denmark, Vol. 68, 11 Supp. July, ABSTRACT p.A575.Africa, South AfricaGondwana, Karoo magmatism
DS200412-0935
2004
Jourdan, F.Jourdan, F., Feraud, G., Betrand, H., Kampunzu, A.B., Tshoso, G., Le Gall, B., Tiercelin, J.J., Capiz, P.The Karoo triple junction questioned: evidence from Jurassic and Proterzoic 40 Ar 39 Ar ages and geochemistry of the giant OkavaEarth and Planetary Science Letters, Vol. 222, 3-4, June 15, pp. 989-1006.Africa, BotswanaGeochronology, mantle plume
DS200512-0489
2005
Jourdan, F.Jourdan, F., Feraud, G., Kampunzu, A.B., Tshoso, G., Watkeys, M.K., Le Gall, B.Karoo large igneous province: brevity, origin and relation to mass extinction questioned by new 40 Ar 39 Ar age data.Geology, Vol. 33, 9, Sept. pp. 745-748.Africa, South AfricaGeochronology
DS200612-0647
2005
Jourdan, F.Jourdan, F., Feraud, G., Bertrand, H., Watkeys, M.K., Kampunzu, A.B., Le Gall, B.Basement control on dyke distribution in Large Igneous Provinces: case study of the Karoo triple junction.Earth and Planetary Science Letters, mantleplumes.orgAfrica, South AfricaGeochronology, mantle plume, structure, tectonics
DS200712-0496
2007
Jourdan, F.Jourdan,F., Bertrand, H., Scharer, U., Blichert-Toft, J., Feraud, G., Kampunzu, A.B.Major and trace element and Sr Nd, Hf, and Pb isotope compositions of the Karoo large igneous province, Botswana and Zimbabwe: lithosphere vs mantle plume...Journal of Petrology, Vol. 48, 6, pp. 1043-1078.Africa, Botswana, ZimbabweGeochemistry, geochronology
DS200912-0121
2009
Jourdan, F.Coltice, N., Betrand, H., Rey, P., Jourdan, F.,Ricard, Y.Global warming of the mantle beneath continents back to the Archean.Gondwana Research, Vol. 15, 3-4, pp. 264-266.MantleGeothermometry
DS200912-0345
2009
Jourdan, F.Jourdan, F., Betrand, H., Fraud, G., LeGall, B., Watkeys, M.K.Lithospheric mantle evolution monitored by overlapping large igneous provinces: case study in southern Africa.Lithos, Vol. 107. 3-4, pp. 257-268.Africa, South AfricaMagmatism
DS201212-0191
2012
Jourdan, F.Evans, N.J., McInnes, B.I.A., McDonald, B., Danisik, M., Jourdan, F., Mayers, C., Thern, E., Corbett, D.Emplacement age and thermal footprint of the Diamondiferous Ellendale E9 lamproite pipe, Western Australia.Mineralium Deposita, in press availableAustraliaDeposit - Ellendale E9
DS201212-0192
2012
Jourdan, F.Evans, N.J., McInnes, B.I.A., McDonald, B., Danisik, M., Jourdan, F., Mayers, C., Thern, E., Corbett, D.Emplacement age and thermal footprint of the Diamondiferous Ellendale E9 lamproite pipe, western Australia.Mineralium Deposita, in press availableAustraliaDeposit - Ellendale E9
DS201212-0341
2012
Jourdan, F.Jourdan, F., Reimold, W.U., Deutsch, A.Dating terrestrial impact structures.Elements, Vol. 8, 1, Feb. pp. 49-53.MantleGeochronology
DS201212-0455
2012
Jourdan, F.McInnes, B.I.A., Evans, N.J., Jourdan, F., McDonald, B.J., Danislk, M., Mayers, C.Zircon U-TH-PB-HE double dating of North Australian diamond fields: Ellendale(WA) Seppelt ( WA) Merlin (NT).10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractAustraliaDeposit - Ellendale, Seppelt, Merlin
DS201212-0456
2012
Jourdan, F.McInnis, B., Evans, N., Jourdan, F., McDonald, B., Gorter, J., Mayers, C., Wilde, S.A Tertiary record of Australian plate motion from ages of Diamondiferous alkalic intrusions.Goldschmidt Conference 2012, abstract 1p.AustraliaGeochronology - Fohn
DS201212-0582
2012
Jourdan, F.Reimold, W.U, Jourdan, F.Impact! Bolides. Craters and catastrophes.Elements, Vol. 8, 1, Feb, pp. 19-24.GlobalImpact Crater
DS201312-0252
2013
Jourdan, F.Evans, N.J., McInnies, B.I.A., McDonald, B., Danisik, M., Jourdan, F., Mayers, C., Thern, E., Corbett, D.Emplacement age and thermal footprint of the Diamondiferous Ellendale E9 lamproite pipe, western Australia.Mineralium Deposita, Vol. 48, 3, pp. 413-421.AustraliaDeposit - Ellendale 9
DS201412-0568
2015
Jourdan, F.McGee, B., Collins, A.S., Trindade, R.I.F., Jourdan, F.Investigating mid-Edicaran glaciation and final Gondwana amalgamation using coupled sedimentology and 40 Ar/39Ar detrital muscovite provenance from the Paraguay Belt, Brazil.Sedimentology, Vol. 62, 1, pp. 130-154.South America, BrazilGeomorphology
DS201508-0348
2015
Jourdan, F.Cucciniello, C., Tucker, R.D., Jourdan, F., Melluso, L., Morra, V.The age and petrogenesis of alkaline magmatism in the Ampasindava Peninsula and Nosy Be archipelago, northern Madagascar.Mineralogy and Petrology, in press available 23p.Africa, MadagascarBasanites, Foidites

Abstract: The Ampasindava alkaline province consists of a series of circular and elliptical intrusions, lava flows, dyke swarms and plugs of Cenozoic age emplaced into the Mesozoic-Cenozoic sedimentary rocks of the Antsiranana basin (NW Madagascar) and above the crystalline basement. The magmatism in the Ampasindava region is linked to a NW-SE trending extensional tectonic setting. New 40Ar/39Ar age determinations on feldspar separate of alkali granites and basaltic dykes yielded ages of 18.01?±?0.36 Ma and 26?±?7 Ma, respectively. Alkali basalts and basanites, nepheline syenites and phonolites, and silica saturated-to-oversaturated syenites, trachytes, granites and rhyolites are the main outcropping lithologies. These rocks have sodic affinity. The felsic rocks are dominant, and range from peraluminous to peralkaline. The mantle-normalized incompatible element patterns of the mafic lavas match those of Na-alkaline lavas in within-plate rift settings. The patterns are identical in shape and absolute concentrations to those of the Bobaomby (Cap d’Ambre) and Massif d’Ambre primitive volcanic rocks. These geochemical features are broadly compatible with variable degrees of partial melting of incompatible element-enriched mantle sources. The mineralogical and geochemical variations are consistent with fractional crystallization processes involving removal of olivine, feldspar, clinopyroxene, amphibole, Fe-Ti oxides and apatite. Removal of small amount of titanite explains the concave upward lanthanide pattern in the evolved nepheline syenites and phonolites, which are additionally rich in exotic silicates typical of agpaitic magmas (eudialyte, F-disilicates).
DS201807-1536
2018
Jourdan, F.Ware, B., Jourdan, F.40Ar/39/Ar geochronology of terrestrial pyroxene.Geochimica et Cosmochimica Acta, Vol. 230, pp. 112-130.Mantlegeochronology

Abstract: Geochronological techniques such as U/Pb in zircon and baddeleyite and 40Ar/39Ar on a vast range of minerals, including sanidine, plagioclase, and biotite, provide means to date an array of different geologic processes. Many of these minerals, however, are not always present in a given rock, or can be altered by secondary processes (e.g. plagioclase in mafic rocks) limiting our ability to derive an isotopic age. Pyroxene is a primary rock forming mineral for both mafic and ultramafic rocks and is resistant to alteration process but attempts to date this phase with 40Ar/39Ar has been met with little success so far.In this study, we analyzed pyroxene crystals from two different Large Igneous Provinces using a multi-collector noble gas mass spectrometer (ARGUS VI) since those machines have been shown to significantly improve analytical precision compared to the previous single-collector instruments. We obtain geologically meaningful and relatively precise 40Ar/39Ar plateau ages ranging from 184.6?±?3.9 to 182.4?±?0.8?Ma (2? uncertainties of ±1.8-0.4%) and 506.3?±?3.4?Ma for Tasmanian and Kalkarindji dolerites, respectively. Those data are indistinguishable from new and/or published U-Pb and 40Ar/39Ar plagioclase ages showing that 40Ar/39Ar dating of pyroxene is a suitable geochronological tool. Scrutinizing the analytical results of the pyroxene analyses as well as comparing them to the analytical result from plagioclase of the same samples indicate pure pyroxene was dated. Numerical models of argon diffusion in plagioclase and pyroxene support these observations. However, we found that the viability of 40Ar/39Ar dating approach of pyroxene can be affected by irradiation-induced recoil redistribution between thin pyroxene exsolution lamellae and the main pyroxene crystal, hence requiring careful petrographic observations before analysis. Finally, diffusion modeling show that 40Ar/39Ar of pyroxene can be used as a powerful tool to date the formation age of mafic rocks affected by greenschist metamorphism and will likely play an important role in high temperature thermochronology.
DS201906-1322
2019
Jourdan, F.McCausland, P., Higgins, M., LeCheminant, A., Jourdan, F., Hamilton, M., Murphy, J.B.Laurentia during the mid-Edicacaran: paleomagnetism and 580 Ma age of the Saint Honore alkali intrusion and related dykes, Quebec. GAC/MAC annual Meeting, 1p. Abstract p. 141.Canada, Quebecdeposit - Saint Honore

Abstract: We sampled the mid-Ediacaran Saint-Honoré alkali intrusion and related dykes in the Saguenay City region of Québec for paleomagnetic and U-Pb, 40Ar/39Ar geochonologic study. 40Ar/39Ar geochronology of phlogopite separates from carbonatite of the central intrusion return plateau ages with a weighted mean of 578.3 ± 3.5 Ma. Baddeleyite from a phoscorite dyke provides a concordant age of 580.25 ± 0.87 Ma for the crystallization of the dykes associated with the St-Honoré intrusive complex. Paleomagnetic results from the intrusion itself and related carbonatite and lamprophyre dykes exhibit some streaking between higher to moderate inclination directions, even at the site level, after screening to remove a steep, present-day viscous remanence. The predominant St-Honoré mean direction (13 sites), which is primary (baked contact test on the host Lac St-Jean anorthosite), is D = 119, I = 72.3°; ?95 = 9.5°, retained at higher coercivity and to high unblocking temperatures by titanomagnetite. Assuming a geocentric axial dipole, this result places the St. Honoré locality at 57° S at ~ 580 Ma, implying that Laurentia straddled mid-paleolatitudes at that time. Notably, the paleopole location at 27.2° N, 320.7 E (dp = 15°, dm = 17°) is consistent with similar mid-Ediacaran age paleopoles which place Laurentia at mid- to high paleolatitudes. The Saint-Honoré result implies that Laurentia had moved from low latitude in the early Ediacaran to higher southern paleolatitudes by 580-570 Ma, and then back to low paleolatitudes by as early as 564 Ma. Viewed as apparent polar wander (APW), this motion traces an 'Ediacaran loop' that can also be seen in similar-aged paleomagnetic results from at least two other paleocontinents. The similar APW loops suggest a role for true polar wander in Ediacaran geodynamics, and perhaps help to define a longitudinally-constrained global Ediacaran paleogeography.
DS201908-1769
2019
Jourdan, F.Alessio, B.L., Glorie, S., Collins, A.S., Jourdan, F., Jepson, G., Nixon, A., Siegfried, P.R., Clark, C.The thermo-tectonic evolution of the southern Congo craton margin as determined from apatite and muscovite thermochronology.Tectonophysics, Vol. 766, pp. 398-415.Africa, Zambia, Malawi, Mozambique, Tanzaniacraton

Abstract: The Southern Irumide Belt (SIB) of Zambia consists of predominantly Mesoproterozoic terranes that record a pervasive tectono-metamorphic overprint from collision between the Congo and Kalahari cratons in the final stages of Gondwana amalgamation. This study applies multi-method thermochronology to samples throughout southern Zambia to constrain the post-collisional, Phanerozoic thermo-tectonic evolution of the region. U-Pb apatite and 40Ar/39Ar muscovite data are used to constrain the cooling history of the region following Congo-Kalahari collision, and reveal ages of c. 550-450?Ma. Variations in the recorded cooling ages are interpreted to relate to localised post-tectonic magmatism and the proximity of analysed samples to the Congo-Kalahari suture. Apatite fission track data are used to constrain the low-temperature thermo-tectonic evolution of the region and identify mean central ages of c. 320-300, 210-200 and 120-110?Ma. Thermal modelling of these samples identifies a number of thermal events occurring in the region throughout the Phanerozoic. Carboniferous to Permian-Triassic heating is suggested to relate to the development of Karoo rift basins found throughout central Africa and constrain the timing of sedimentation in the basin. Permian to Jurassic cooling is identified in a number of samples, reflecting exhumation as a result of the Mauritanian-Variscan and Gondwanide orogenies. Subsequent cooling of the majority of samples occurs from the Cretaceous and persists until present, reflecting exhumation in response to larger scale rifting associated with the break-up of Gondwana. Each model reveals a later phase of enhanced cooling beginning at c. 30?Ma that, if not an artefact of modelling, corresponds to the development of the East African Rift System. The obtained thermochronological data elucidate the previously unconstrained thermal evolution of the SIB, and provides a refined regional framework for constraining the tectonic history of central Africa throughout the Phanerozoic.
DS202204-0516
2022
Jourdan, F.Boscaini, A., Marzoli, A., Bertrand, H., Chiagradia, M., Jourdan, F., Faccende, M., Meyzen, C.M., Callegaro, S., Duran, L. Cratonic keels controlled the emplacement of the Central Atlantic Magmatic Province ( CAMP)Earth and Planetary Science Letters, Vol. 584, doi 10.1016/j.espl.2022.117480Africa, Mali, Mauritaniacraton

Abstract: Large Igneous Provinces (LIPs) are exceptionally voluminous magmatic events frequently related to continental break-up, global climate changes and mass extinctions. One interesting aspect of many LIPs is their spatial proximity to cratons, begging the question of a potential control of thick lithosphere on their emplacement. In this study, we investigate the relationship between the emplacement of the Central Atlantic Magmatic Province (CAMP) and the thick lithospheric mantle of the Precambrian cratons that formed the central portion of Pangea and are currently located on the continents surrounding the Central Atlantic Ocean. CAMP outcrops are frequently located over the margins of the thick cratonic keels, as imaged by recent tomographic studies, suggesting a role of lithosphere architecture in controlling magma genesis and emplacement. Here we focus on CAMP dykes and sills from the Hank, Hodh, and Kaarta basins in North-Western Africa (NW-Africa, Mali and Mauritania) emplaced at the edge of the Reguibat and Leo-Man Shields. The investigated intrusive rocks show compositions similar to most CAMP magmas, in particular those of the Tiourjdal geochemical group, limited to NW-Africa, and of the Prevalent group, occurring all over the CAMP. Geochemical modelling of CAMP basalts requires a Depleted MORB Mantle (DMM) source enriched by recycled continental crust (1-4%) and melting beneath a lithosphere of ca. 80 km in thickness. On the contrary, melting under a significantly thicker lithosphere (>110 km) does not produce magmas with compositions similar to those of CAMP basalts. This suggests that CAMP magmatism was likely favoured by decompression-induced partial melting of the upwelling asthenospheric mantle along the steep lithospheric boundaries of stable cratons. The architecture of the pre-existing lithosphere (i.e., the presence of stable thick cratonic keels juxtaposed to relatively thinner lithosphere) appears to have been a critical factor for localizing mantle upwelling and partial melting during extensive magmatic events such as in the CAMP.
DS1986-0413
1986
Jourdan, P.Jourdan, P.The minerals industry of AngolaRaw Materials report, Vol. 5, No.1, pp.20-40AngolaDiamond, Production
DS1988-0336
1988
Jourdan, P.Jourdan, P.The minerals sector of Tanzania. Brief section 4 pages on diamondsInstitute of Mining Research, Report No. 78, pp, 9-12TanzaniaBrief overview production history, Diamonds
DS1989-0728
1989
Jourdan, P.Jourdan, P.The mineral economies of the SADCC: NamibiaRaw Materials Report, Vol. 7, No. 1, pp. 6-17Southwest Africa, NamibiaEconomics -mining, Diamonds production-compa
DS1989-0729
1989
Jourdan, P.Jourdan, P.The mineral economies of the SADCC: TanzaniaRaw Materials Report, Vol. 7, No. 1, pp. 18-31TanzaniaEconomics -mining, Diamonds production (Will
DS1990-0780
1990
Jourdan, P.Jourdan, P.The minerals industry of Angola. Extracted information on diamondsInstitute of Mining Research, University of Zimbabwe, Report No. 116, pp. 9, 10, 11AngolaDiamond production, Brief overview
DS1990-0781
1990
Jourdan, P.Jourdan, P.The minerals industry of SwazilandInstitute Min. Research University of Zimbabwe, IMR No. 104, 9pGlobalEconomics, Overview
DS1990-0782
1990
Jourdan, P.Jourdan, P.The minerals industry of Namibia. Extracted information on diamondsInstitute of Mining Research, University of Zimbabwe, Report No. 115, 1pNamibiaDiamond production, Brief overview
DS1990-0783
1990
Jourdan, P.Jourdan, P.The minerals industry of Tanzania. Extracted information on diamondsInstitute of Mining Research, University of Zimbabwe, Report No. 119, pp. 5, 6, 7TanzaniaDiamond production, Brief overview
DS1990-0784
1990
Jourdan, P.Jourdan, P., Carlsson, J.The minerals industry of Botswana. Diamonds pp. 8-10Institute of Mining Research, University of of Zimbabwe, Report No. 106, May, 17p. p. 8-10. diamondsBotswanaEconomics, Diamonds
DS1991-0810
1991
Jourdan, P.Jourdan, P.United States mineral dependence on South Africa: exploding the myths.Diamonds pp.3-4Institute of Mining Research, University of of Zimbabwe, Report No. 89, August, 17p. p. 3-4 diamondsSouth AfricaDiamond -brief overview, Economics
DS1993-0762
1993
Jourdan, P.Jourdan, P.Mining industry in a democratic South AfricaRaw Materials Report, Vol. 9, No. 4, pp. 20-23South AfricaCountry profile, Mining industry
DS1993-0763
1993
Jourdan, P.Jourdan, P.Mining industry in a democratic South AfricaRaw Materials Report, Vol. 9, No. 4, pp. 20-23.South AfricaMining Industry, Economics
DS1994-0853
1994
Jourdan, P.Jourdan, P.ANC policy on mining and minerals processingAnc Department Of Economic Planning, 6p.South AfricaMining legislation, Mining policy
DS1996-0700
1996
Jourdan, P.Jourdan, P.Adding value to South Africa's mineralsJournal of Mineral Policy, Vol. 12, No. 1, pp. 3-13South AfricaEconomics, Legal
DS2003-1444
2003
Jourdan, P.Walker, M., Jourdan, P.Resource based sustainable development: an alternative approach to industrialization inMinerals and Energy, Raw Materials Report, Vol. 18, 3, Sept. pp. 25-34.South AfricaLegal, economics
DS200412-2073
2003
Jourdan, P.Walker, M., Jourdan, P.Resource based sustainable development: an alternative approach to industrialization in South Africa.Minerals & Energy - Raw Materials Report, Vol. 18, 3, Sept. pp. 25-34.Africa, South AfricaLegal, economics
DS1995-0896
1995
Jourdan, P.P.Jourdan, P.P.The mining sector in southern AfricaSapes Book, 120pSouth Africa, Zimbabwe, BotswanaBook -table of contents, Mining -Southern Africa
DS1993-1242
1993
Jourde, G.Pinna, P., Jourde, G., Calvez, J.Y., Mroz, J.P., Marques, J.M.The Mozambique Belt in northern Mozambique: Neoproterozoic 1100-850 Macrustal growth and tectogenesis and superimposed Pan-African 800-550 MatectonisM.Precambrian Research, Vol. 62, No. 1-2, April pp. 1-60GlobalTectonics, Mozambique
DS1989-0730
1989
Journal do BrasilJournal do BrasilDiamante de 224 quilates some e ha suspeita de contrabando.(in Portugese)Journal of do Brasil, Newspaper (in Portugese)., July 20, p. 14BrazilNews item, Diamond 224
DS1989-0731
1989
Journal of African Earth SciencesJournal of African Earth SciencesSpecial issue: African rifting. Individual specific reference citations are listed seperatelyJournal of African Earth Sciences, Vol. 8, No. 2/3/4, pp. 137- 617AfricaTectonics, Rifting - special issue
DS1991-0811
1991
Journal of African Earth SciencesJournal of African Earth SciencesSpecial issue: Precambrian sedimentary basins of southern AfricaJournal of African Earth Sciences, Vol. 13, No. 1, pp. 1-150Southern AfricaBasins, Greenstone belts
DS1994-0854
1994
Journal of African Earth SciencesJournal of African Earth SciencesMozambique and related belts in Zambia and MalawiJournal of African Earth Sciences, Vol. 19, No. 3, Oct. pp. 153-250Zambia, Malawi, Zimbabwe, Tanzania, AntarcticaBook -table of contents, Tectonics, metamorphism
DS1997-0565
1997
Journal of African Earth SciencesJournal of African Earth SciencesInternational Geological Correlation Programme (IGCP) 348 Mozambique and related beltsJournal of African Earth Sciences, Vol. 23, No. 3, Oct. pp. 269-500GlobalTectonics, shear zones, suture zones, rare earths, Thermobarometry
DS1998-0706
1998
Journal of African Earth SciencesJournal of African Earth SciencesEast African Rift systems.... special issueJournal of African Earth Sciences, Vol. 26, No. 3, pp. 343-494.East AfricaTectonics, Rift systems
DS1998-0707
1998
Journal of African Earth SciencesJournal of African Earth SciencesEast African Rift systemJournal of African Earth Sci, Vol. 26, No. 3, pp. 343-495East Africa, TanzaniaRift system, Tectonics
DS200612-0648
2006
Journal of African Earth SciencesJournal of African Earth SciencesMesozoic orogenic belts in southern and central Africa. Katanga DRC, Irumide Zambia, Natal South Africa, Namibia, Kalahari Craton magmatism.Journal of African Earth Sciences, Vol. 46, 1-2, Sept. pp. 1-172. whole issueAfrica, Democratic Republic of Congo, Zambia, South Africa, NamibiaBook - orogeny
DS200812-0528
2007
Journal of Applied CrystallographyJournal of Applied CrystallographyOn the role of nitrogen in stiffening the diamond structure.Journal of Applied Crystallography, Vol. 40, 6, pp. 1146-1152.TechnologyDiamond morphology
DS1860-0094
1870
Journal of Applied ScienceJournal of Applied ScienceSouth African Diamond Washing MachinesJournal of Applied Science, Vol. 1, DECEMBER P. 183.Africa, South AfricaMining recovery
DS1860-0289
1878
Journal of Applied ScienceJournal of Applied ScienceDiamonds in California, 1878 El DoradoJournal of Applied Science, Vol. 9, SEPT. 2, P. 144.United States, CaliforniaDiamond Occurrence
DS1993-0764
1993
Journal of Geochemical ExplorationJournal of Geochemical ExplorationGeochemical mapping... papers from Gold schmidt Conference held May 1992Journal of Geochemical Exploration, Vol. 49, No. 1-2, November pp. 3-212China, Greenland, Canada, Germany, United Kingdom, NewfoundlandGeochemical mapping, Analytical techniques ICP-ES, ICP-MS, Geochemistry -environmental, Spectrometry
DS1995-0897
1995
Journal of Geochemical ExplorationJournal of Geochemical ExplorationHeavy metal aspects of mining pollution and its remediationJournal of Geochemical Exploration, Vol. 52, No. 1-2, Jan. pp. 1-280British Columbia, Nevada, Papua New Guinea, Cuba, BrazilBook -table of contents, Environmental processes, mineral processing
DS1997-0566
1997
Journal of Geochemical ExplorationJournal of Geochemical ExplorationEnvironmental geochemical baseline mapping in Europe... Finland, ChinaJournal of Geochem. Expl, Vol. 60, No. 1, Nov. pp. 1-120Europe, Slovakia, Poland, Hungary, Lithuania, SardiniaGeochemistry, Environmental
DS1998-0708
1998
Journal of Geochemical ExplorationJournal of Geochemical ExplorationGeochemical engineering: current applications and future trendsJournal of Geochem. Expl, Vol. 62, No. 1-3, 360pGlobalBook - table of contents, Geochemistry, engineering
DS1989-0732
1989
Journal of Geological Society IndiaJournal of Geological Society IndiaAlternative sources of diamondJournal of Geological Society India, Vol. 34, No. 1, July p. 109IndiaDiamond, Genesis
DS1993-0765
1993
Journal of Geological Society IndiaJournal of Geological Society IndiaIndia diamond potentialJournal Geological Society of India, Vol. 41, No. 2, February, p. 179IndiaNews item, Diamonds
DS1989-0733
1989
Journal of Geophysical ResearchJournal of Geophysical ResearchAlkaline volcanism in Island Arcs. Special sectionJournal of Geophysical Research, Vol. 94, No. B4, April 10, pp. 4467-4700GlobalShoshonite
DS1990-0785
1990
Journal of Geophysical ResearchJournal of Geophysical ResearchSilicate melts and mantle petrogenesis (in memory of Christopher M.Scarfe)Journal of Geophysical Research, Vol. 95, No. B 10, September 10, pp. 15, 661-15, 954GlobalMantle petrogenesis, Silicate melts
DS201212-0342
2012
Journal of Metamorphic GeologyJournal of Metamorphic GeologyIntroduction to a virtual special issue on crustal melting.Journal of Metamorphic Geology, Vol. 30, pp. 453-356.MantleMelting
DS1998-0709
1998
Journal of Mineral PolicyJournal of Mineral PolicyUNCTAD: commodity resources - sustainable developmentJournal of Mineral Policy, Vol. 13, No. 2, pp. 34-40Papua New GuineaEconomics, Environmental
DS1860-1058
1899
Journal of Society of ArtsJournal of Society of ArtsDiamond Production of the TransvaalJournal of Society of Arts, Vol. 47, P. 849.Africa, South AfricaMining Recovery
DS1995-0898
1995
Journal of South American Earth SciencesJournal of South American Earth SciencesGeology of the Borborema Province, northeast BrasilJournal of South American Earth Sciences, Vol. 8, No. 3-4, July-October pp. 233-420BrazilBrasiliano Belt, shear zone, Structure
DS1996-0701
1996
Journal of South American Earth SciencesJournal of South American Earth SciencesAndean GeodynamicsJournal of South American Earth Sciences, Vol. 9, No. 1-2, Jan-Mar pp. 1-150Argentina, Colombia, Peru, BoliviaAndes tectonics, Table of contents
DS1996-0702
1996
Journal of Southeast Asian Earth SciencesJournal of Southeast Asian Earth SciencesPrecambrian India within east GondwanaJournal of Southeast Asian Earth Sciences, Vol. 14, No. 3-4, Oct.Nov. pp.. 117-310IndiaGondwana, Tectonics, geochronology
DS200912-0346
2009
Journal of the Geological Society of IndiaJournal of the Geological Society of IndiaIdentification of nano diamonds in recent impact material.Journal of the Geological Society of India, Vol. 73, no. 3, March, p. 445 ( 1/8p.)United States, CanadaMeteorite - impacts
DS201112-0486
2010
Journal of the Geological Society of IndiaJournal of the Geological Society of IndiaNew dat a on kimberlites and related rocks of India.Journal of the Geological Society of India, Vol. 75, p. 569.India, Andhra PradeshKimberlites, boninites - brief
DS1900-0089
1902
Journal of the Society of ArtsJournal of the Society of ArtsDiamonds and Carbon in BrasilJournal of SOC. ARTS (London), Vol. 50, PP. 928-930.South America, BrazilOrigin, Classification
DS1960-1137
1969
Journeaux, C.P.Journeaux, C.P.Operations at Consolidated African Selection Trust Limited, akwatia, Ghana.Commonwealth Min. Met. Congress 9th., 25P.Ghana, West AfricaAlluvial Placers, Mining Recovery, Diamond
DS1990-1080
1990
Journel, A.Myers, D.E., Journel, A.Variograms with zonal anisotropies and noninvertible kriging systemsMathematical Geology, Vol. 22, No. 7, pp. 779-785GlobalGeostatistics, Variograms
DS1975-0771
1978
Journel, A.G.Journel, A.G., et al.Mining Geostatistics. Reprintwww.blackburnpress.com/mige 600p. $ 69.95, GlobalBlank
DS1989-0734
1989
Journel, A.G.Journel, A.G., Alabert, F.Non-gaussian dat a expansion in the earths sciencesTerra Nova, Vol. 1, No. 2, pp. 123-134. Database #18051GlobalComputer, Geostatistics
DS1989-0735
1989
Journel, A.G.Journel, A.G., Rossi, M.E.When do we need a trend model in kriging?Mathematical Geology, Vol. 21, No. 7, October pp. 715-739. # 18146GlobalGeostatistics, Kriging -trend model
DS1991-1255
1991
Journel, A.G.Olea, R.A., Christakos, G., David, M., Journel, A.G., Krige, D.G.Geostatistical glossary and multilingual dictionaryOxford University of Press, 288p. $ 55.95 approxGlobalGeostatistics -glossary
DS1991-1676
1991
Journel, A.G.Suro-Perez, V., Journel, A.G.Indicator principal component krigingMathematical Geology, Vol. 23, No. 5, July pp. 759-788GlobalGeostatistics, Kriging
DS1992-0360
1992
Journel, A.G.Deutsch, C.V., Journel, A.G.GSLIB: geostatistical software library user's guideOxford University of Press, 336p. approx. $ 50.00 United StatesGlobalGeostatistical software, Book -ad
DS1993-0343
1993
Journel, A.G.Deutsch, C.V., Journel, A.G.GSLIB Geostatistical software library and user's guideOxford University Press, 336p. approx. $ 70.00GlobalBook -ad, GSLIB -geostatistical software
DS1993-0766
1993
Journel, A.G.Journel, A.G., Deutsch, C.V.Entropy and spatial disorderMathematical Geology, Vol. 25, No. 3, April pp. 329-356GlobalComputer, geostatistics, Program
DS1996-0703
1996
Journel, A.G.Journel, A.G.Modelling uncertainty and spatial dependence: stochastic imagingInternational Journal of Geographical Information Systems, Vol. 10, No. 5, pp. 517-522GlobalGeostatistics, Stochastic imaging
DS1998-0341
1998
Journel, A.G.Deutsch, C.V., Journel, A.G.GSLIB Geostatistical software library and users guideOxford, $ 370p. $ 91.00GlobalBook - table of contents, Geostatistics
DS200412-0936
1978
Journel, A.G.Journel, A.G., HuijbregtsMining geostatistics. REPRINTblackburnpress.com, 600p. $ 69.95TechnologyBook - geostatistics
DS200812-0909
2007
Journel, A.G.Polyakova, E., Journel, A.G.The Nu expression for probablistic dat a integration.Mathematical Geology, Vol. 39, pp. 715-733.TechnologyStatistical probability - not specific to diamonds
DS1985-0316
1985
Jovanovic, L.Jovanovic, L., Ntaflos, TH., Kurat, G.Petrology of Some Ultramafic Xenoliths from the Kimberlites of Yakutia.Terra Cognita., Vol. 5, No. 4, AUTUMN, P. 442. (abstract.).Russia, YakutiaPetrology, Mir, Udacnaya, Obnazenaya, Dama, Lesotho
DS200512-0200
2004
Jovanovic, M.Cvetkovic, V., Downes, H., Prelevic, D., Jovanovic, M.Characteristics of the lithospheric mantle beneath East Serbia inferred from ultramafic xenoliths in Paleogene basanites.Contributions to Mineralogy and Petrology, Vol. 148, 3, pp. 335-357.Europe, SerbiaBasanites, Foidites
DS200712-0173
2007
Jovanovic, Z.Chen, L-H., Jiang, S-Y., Hofmann, A.W., Jovanovic, Z., Xie, L-W., Zhou, X-H.Are peridotite xenoliths in Mesozoic plutons inherited from Paleozoic kimberlites?Plates, Plumes, and Paradigms, 1p. abstract p. A166.ChinaNorth China Craton
DS201712-2713
2017
Jovovic, I.Nicoli, G., Thomassot, E., Schannor, M., Vezinet, A., Jovovic, I.Constraining a Precambrian Wilson Cycle lifespan: an example from the ca. 1.8Ga Nagssugtoqidian Orogen, southeastern Greenland.Lithos, in press available 68p.Europe, GreenlandWilson cycle

Abstract: In the Phanerozoic, plate tectonic processes involve the fragmentation of the continental mass, extension and spreading of oceanic domains, subduction of the oceanic lithosphere and lateral shortening that culminate with continental collision (i.e. Wilson cycle). Unlike modern orogenic settings and despite the collection of evidence in the geological record, we lack information to identify such a sequence of events in the Precambrian. This is why it is particularly difficult to track plate tectonics back to 2.0 Ga and beyond. In this study, we aim to show that a multidisciplinary approach on a selected set of samples from a given orogeny can be used to place constraints on crustal evolution within a P-T-t-d-X space. We combine field geology, petrological observations, thermodynamic modelling (Theriak-Domino) and radiogenic (U-Pb, Lu-Hf) and stable isotopes (?18O) to quantify the duration of the different steps of a Wilson cycle. For the purpose of this study, we focus on the Proterozoic Nagssugtoqidian Orogenic Belt (NOB), in the Tasiilaq area, South-East Greenland. Our study reveals that the Nagssugtoqidian Orogen was the result of a complete three stages juvenile crust production (Xjuv) - recycling/reworking sequence: (I) During the 2.60-2.95 Ga period, the Neoarchean Skjoldungen Orogen remobilised basement lithologies formed at TDM 2.91 Ga with progressive increase of the discharge of reworked material (Xjuv from 75% to 50%; ?18O: 4-8.5‰). (II) After a period of crustal stabilization (2.35-2.60 Ga), discrete juvenile material inputs (?18O: 5-6‰) at TDM 2.35 Ga argue for the formation of an oceanic lithosphere and seafloor spreading over a period of ~ 0.2 Ga (Xjuv from < 25% to 70%). Lateral shortening is set to have started at ca. 2.05 Ga with the accretion of volcanic/magmatic arcs (i.e. Ammassalik Intrusive Complex) and by subduction of small oceanic domains (M1: 520 ± 60 °C at 6.6 ± 1.4 kbar). (III) Continental collision between the North Atlantic Craton and the Rae Craton occurred at 1.84-1.89 Ga. Crustal thickening of ~ 25 km was accompanied by regional metamorphism M2 (690 ± 20 °C at 6.25 ± 0.25 kbar) and remobilization of pre-existing supracrustal lithologies (Xjuv ~ 40%; ?18O: 5-10.5‰). Rates and durations obtained for seafloor spreading (175 ± 25 Ma), subduction (125 ± 75 Ma) and continental collision (ca. 60 Ma) are similar to those observed in Phanerozoic Wilson Cycle but differ from what was estimated for Archean terrains. Therefore, timespans of the different steps of a Wilson cycle might have progressively changed over time as a response to the progressive cratonization of the lithosphere.
DS1991-0812
1991
Jowhar, T.N.Jowhar, T.N.A FORTRAN 77 computer program for calculating thermodynamic properties of minerals at higher temperatures and pressuresNeus Jahrb. Min. Monatsche, 1991, Hefte 5, pp. 217-222GlobalComputer, Program -thermodynamic properties of minerals
DS201312-0899
2013
Jowitt, S.M.Tait, J., Straathof, G., Soderlund, U., Ernst, R.E., Key, R., Jowitt, S.M., Lo, K., Dahmada, M.E.M., N'Diaya, O.The Ahmeyim Great Dyke of Mauritania: a newly dated Archean intrusion.Lithos, Vol. 174, pp. 323-332.Africa, MauritaniaGeochronology
DS201811-2570
2018
Jowitt, S.M.Ernst, R.E., Davies, D.R., Jowitt, S.M., Campbell, I.H.When do mantle plumes destroy diamonds? ( review )Earth and Planetary Science Letters, Vol. 502, pp. 244-252.Russia, Canada, Ontario, Attawapiskatkimberlite, core boundary

Abstract: Mantle plumes are hot buoyant upwellings that rise from Earth's core-mantle-boundary to its surface where they can produce large igneous provinces (LIPs) and volcanic tracks, such as the Siberian Traps and the Hawaiian Emperor chain, respectively. We show that flattened mantle plume heads, which can have radii of >1200 km in the uppermost mantle, can heat the overlying lithospheric mantle to temperatures above the diamond stability field. As a consequence, they can destroy diamonds within the roots of Archean cratons, the principal source of diamonds in kimberlites. We quantitatively demonstrate that there is a ‘sour spot’ for this effect that occurs when lithospheric thicknesses are 165-185 km and the plume has a temperature of >150?°C above background mantle. Our model explains why the kimberlites associated with the 370 Ma Yakutsk-Vilyui plume in the Siberian craton are diamondiferous whilst those associated with the younger 250 Ma Siberian Traps plume are barren. We also show that the time required to restore the pre-plume thermal structure of the lithosphere is ca. 75-120 Myr, and that destroyed diamonds may regrow once the plume's thermal effect dissipates. The 1100 Ma Kyle Lake and adjacent 180-150 Ma Attawapiskat kimberlites in the southern Superior craton exemplify this, where the older kimberlites are associated with a narrower diamond window (<30 km) in comparison with the ca. 85 km diamond window of the younger Attawapiskat field.
DS201908-1776
2019
Jowitt, S.M.Ernst, R.E., Liikane, D.A., Jowitt, S.M., Buchan, K.L., Blanchard, J.A.A new plumbing system framework for mantle plume related continental large igneous provinces and their mafic ultramafic intrusions.Journal of Volcanology and Geothermal Research, in press available 34p. PdfGlobalmantle plumes, hotspots

Abstract: The magmatic components of continental Large Igneous Provinces (LIPs) include flood basalts and their plumbing system of giant mafic dyke swarms (radiating, linear, and the recently discovered circumferential type), mafic sill provinces, a lower crustal magmatic underplate, mafic-ultramafic (M-UM) intrusions, associated silicic magmatism, and associated carbonatites and kimberlites. This paper proposes a new plumbing system framework for mantle plume-related continental LIPs that incorporates all of these components, and provides a context for addressing key thematic aspects such as tracking magma batches "upstream" and "downstream" and their geochemical evolution, assessing the setting of M-UM intrusions and their economic potential, interpreting deep magmatic component identified by geophysical signatures, and estimating magnitudes of extrusive and intrusive components with climate change implications. This plumbing system model, and its associated implications, needs to be tested against the rapidly improving LIP record.
DS202105-0770
2021
Jowitt, S.M.Jowitt, S.M., McNulty, B.A.Geology and mining: mineral resources and reserves: their estimation, use, and abuse. *** not specific to diamonds .. Of interest for studentsSEG Discovery, No. 125, April pp. 27-36. pdfGlobaloverview

Abstract: Resource and reserve estimation is a critical step in mine development and the progression from mineral exploration to commodity production. The data inputs typically change over time and reflect variations in geoscientific knowledge as well as the modifying factors required by regulation for estimating a reserve. These factors include mineral (ore) processing, metallurgical treatment of the ore, infrastructure requirements for mine and workforce, and the transportation of processed products to buyers; others that will affect the production of metals and/or minerals from a deposit include economic, marketing, legal, environmental, social, and governmental factors. All are needed by the mining industry to quantify the contained mineralization within mineral deposits that likely warrant the significant capital investment required to build a mine. However, these resource and reserve data are estimates that change over time due to unpredicted variations in the initial inputs. Paramount to the two estimates are the quality and accuracy of the geologic inputs and the communication of these to the professionals tasked with making each estimate. Geostatistical processing of the grade of the resource has become a dominant element of the estimation process, but this requires transparent and informed communication between geologists and mining engineers with the geostatistician responsible for mathematically processing the grade data. Regulatory constraints also mean that estimated resources and reserves seldom capture the full extent of a mineral deposit. Similarly, co- and by-product metals and minerals that are commonly produced by mines may not be captured by resource and reserve estimates because of their limited economic contribution. This suggests that reporting standards for co- and by-products—particularly for the critical metals that may have a sharp increase in demand—need improvement. Finally, the importance of these data to the mining industry is such that informing investors and the broader public about the nature of resource and reserve estimates, and the meaning of associated terminology, is also essential when considering the global metal and mineral supply, and the role of mining in modern society.
DS201508-0376
2015
Joy, B.Schulze, D.J., Davis, D.W., Helmstaedt, H., Joy, B.Timing of the Cenozoic " Great Hydration" event beneath the Colorado Plateau: Th-Pb dating of monazite in Navajo volcanic field metamorphic eclogite xenoliths.Geology, Vol. 43, pp. 727-730.United States, Colorado PlateauDiatremes - Moses Rock, Mule's Ear, Garnet Ridge, Cane Valley, Red Mesa, Buell Park, Green Knobs
DS201212-0339
2012
Joy, S.Jelsma, H.,Krishnan, S.U., Perritt, S.,Kumar, M., Preston, R., Winter, F., Lemotlo, L., Costa, J., Van der Linde, G., Facatino, M., Posser, A., Wallace, C., Henning, A., Joy, S., Chinn, I., Armstrong, R., Phillips, D.Kimberlites from central Angola: a case stidy of exploration findings.10th. International Kimberlite Conference Feb. 6-11, Bangalore India, AbstractAfrica, AngolaOverview of kimberlites
DS201212-0343
2012
Joy, S.Joy, S., Jelsma, H.A., Preston, R.F., Kota, S.Geology and diamond provenance of the Proterozoic Banganapalle conglomerates, Kurnool Group, India.Geological Society of London Special Publication, No. 365, pp. 197-218.IndiaDeposit - Banganapalle
DS201212-0553
2012
Joy, S.Phillips, D., Giullani, A., Jelsma, H., Joy, S.40Ar/39AR analyses of kelphite: a new approach for dating kimberlites and related rocks.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractAfrica, South Africa, AngolaDeposit Dando Kwanza
DS201312-0559
2013
Joy, S.Lynn, M., Joy, S., Preston, R.The geology and geochemistry of the Wadagera kimberlite and the characteristics of the underlying subcontinental lithospheric mantle, Dharwar craton, India.Proceedings of the 10th. International Kimberlite Conference, Vol. 1, Special Issue of the Journal of the Geological Society of India,, Vol. 1, pp. 167-181.IndiaDeposit - Wadagera
DS201412-0427
2013
Joy, S.Jelsma, H., Krishnan, U., Perritt, S., Preston, R., Winter, F., Lemotlo, L., van der Linde, G., Armstrong, R., Phillips, D., Joy, S., Costa, J., Facatino, M., Posser, A., Kumar, M., Wallace, C., Chinn, I., Henning, A.Kimberlites from central Angola: a case study of exploration findings.Proceedings of the 10th. International Kimberlite Conference, Vol. 2, pp. 173-190.Africa, AngolaExploration - kimberlites
DS201809-2047
2018
Joy, S.Joy, S., Van der Linde, G., Choudbury, A.K., Deb, G.K., Tappe, S.Reassembly of the Dharwar and Bastar cratons at ca. 1 Ga: evidence from multiple tectonothermal events along the Karimnagar granulite belt and Khammam schist belt, southern India.Journal of Earth System Science, Vol. 127, 6, pp. 76- doi:10.1007/s12040-018-0988-2Indiacratons

Abstract: The northern part of the Nellore-Khammam schist belt and the Karimnagar granulite belt, which are juxtaposed at high angle to each other have unique U-Pb zircon age records suggesting distinctive tectonothermal histories. Plate accretion and rifting in the eastern part of the Dharwar craton and between the Dharwar and Bastar craton indicate multiple and complex events from 2600 to 500 Ma. The Khammam schist belt, the Dharwar and the Bastar craton were joined together by the end of the Archaean. The Khammam schist belt had experienced additional tectonic events at ?1900 and ?1600 Ma. The Dharwar and Bastar cratons separated during development of the Pranhita-Godavari (P-G) valley basin at ?1600 Ma, potentially linked to the breakup of the Columbia supercontinent and were reassembled during the Mesoproterozoic at about 1000 Ma. This amalgamation process in southern India could be associated with the formation of the Rodinia supercontinent. The Khammam schist belt and the Eastern Ghats mobile belt also show evidence for accretionary processes at around 500 Ma, which is interpreted as a record of Pan-African collisions during the Gondwana assembly. From then on, southern India, as is known today, formed an integral part of the Indian continent.
DS200612-1411
2006
JoyceTappe, S., Foley, S.F., Jenner, G.A., Heaman, L.M., Kjarsgaard, B.A., Romer,R.L., Stracke, A., Joyce, HoefsGenesis of ultramafic lamprophyres and carbonatites at Aillik Bay, Labrador: a consequence of incipient lithospheric thinning beneath the North Atlantic CratonJournal of Petrology, Vol. 47,7, pp. 1261-1315.Canada, LabradorCarbonatite
DS1992-0808
1992
Joyce, C.Joyce, C., McIlveen, G., Ryan, P.Update of environmental regulatory controls on Mines in AustraliaAustralian Institute of Mining and Metallurgy (AusIMM) Bulletin, No. 3, May pp. 59, 60, 62, 63, 65-67AustraliaLegal -Environmental, Mining
DS1960-0483
1964
Joyce, E.B.Ollier, C.D., Joyce, E.B.Volcanic Physiography of the Western Plains of VictoriaRoyal Society. VICTORIA Proceedings, Vol. 77, PP. 357-376.Australia, VictoriaDiatreme
DS1995-0491
1995
Joyce, E.B.Elliott, C.I., Wilson, C.J.L., Joyce, E.B., Campbell, I.C.Field verification of remotely sensed regional lineaments in the BonaparteBasin, northwest Australia.Iagod Giant Ore Deposits Workshop, J. Kutina, 7p.AustraliaRemote sensing, Lineaments - not specific to diamonds
DS1975-1016
1979
Joyce, J.Ferguson, J., Arculus, R.J., Joyce, J.Kimberlite and Kimberlitic Intrusives of Southeastern Australia: a Review.B.m.r. Journal of Aust. Geol. Geophys., Vol. 4, PP. 227-241.Australia, New South Wales, VictoriaKimberlite, Nepheline Basanites
DS1986-0672
1986
Joyce, J.Robey, J.V.A., Bristowm J.W., Marxm M.R., Joyce, J., Danchin, R.V.Alkalic ultrabasic dykes of the southeast Yilgarn margin,WesternAustraliaProceedings of the Fourth International Kimberlite Conference, Held Perth, Australia, No. 16, pp. 142-144AustraliaBlank
DS1989-1284
1989
Joyce, J.Robey, J.V.A., Bristow, J.W., Marx, M.R., Joyce, J., Danchin, R.V.Alkaline ultrabasic dikes near Norseman, western AustraliaGeological Society of Australia Inc. Blackwell Scientific Publishing, Special, No. 14, Vol. 1, pp. 382-391AustraliaGeochronology, Lamprophyre
DS1998-1598
1998
Joyce, J.Wyatt, B.A., Wenyun, M., Ziyun, L., Joyce, J., Colgan..The Ningxiang lamproites, Hunan Province, China: petrology and mineralchemistry.7th International Kimberlite Conference Abstract, pp. 965-7.China, Hunan ProvinceLamproites, Petrography, mineral chemistry
DS200712-1069
2007
Joyce, N.Tappe, S., Foley, S.F., Stracke, A., Romer, R.L., Kjarsgaard, B.A., Heamna, L.M., Joyce, N.Craton reactivation on the Labrador sea margins 40Ar 39Ar age and Sr Nd Hf Pb isotope constraints from alkaline and carbonatite intrusives.Earth and Planetary Science Letters, Vol. 256, 3-4, pp. 433-454.CanadaCarbonatite
DS201707-1368
2017
Joyce, N.L.Skipton, D.R., Schneider, D.A., Kellett, D.A., Joyce, N.L.Deciphering the Paleoproterozoic cooling history of the northeastern Trans-Hudson Orogen, Baffin Island ( Canada), using 40Ar/39Ar step heating and UV laser thermochrobology.Lithos, Vol. 284-285. pp. 69-90.Canada, Nunavut, Baffin Islandgeothermometry

Abstract: The previously unstudied cooling and exhumation history of mid-crustal rocks exposed on southeastern Baffin Island (Canada) provides new insights into the post-orogenic evolution of the Paleoproterozoic Trans-Hudson Orogen (THO). New 40Ar/39Ar step-heat analyses of biotite, muscovite and phlogopite and core-to-rim intra-grain 40Ar/39Ar analyses of muscovite have a range of apparent ages compatible with slow regional cooling following peak metamorphism. Twenty-nine amphibolite- to granulite-facies rocks were dated using the 40Ar/39Ar step-heating laser (CO2) method. 40Ar/39Ar spot analyses were performed across muscovite grains from three samples using an ultraviolet (UV) laser to investigate intra-grain 40Ar/39Ar age variations. Step-heating apparent ages range from ca. 1788–1622 Ma for biotite, 1720–1630 Ma for phlogopite and 1729–1657 Ma for muscovite. UV spot 40Ar/39Ar analyses in the three muscovite grains range from ca. 1661–1640 Ma, 1675–1645 Ma and 1680–1652 Ma, with core-to-rim apparent age gradients of 20–30 Myr. Previous studies resolved peak metamorphism in this region to between ca. 1860 and 1820 Ma and identified late- to post-THO zircon and monazite populations at ca. 1800–1750 Ma. Numerical diffusion models for Ar in muscovite were conducted to test different Proterozoic cooling and exhumation scenarios. Comparisons with our 40Ar/39Ar ages attest to cooling rates of ~ 1–2 °C/Myr following peak metamorphism and ~ 1.5–2.5 °C/Myr after ca. 1740 Ma. Anomalously old apparent 40Ar/39Ar ages, in cases equivalent to U–Pb zircon rim and monazite ages, likely result from incorporation of excess Ar. The results suggest that mid-crustal rocks on southeastern Baffin Island remained hotter than ~ 420–450 °C for ~ 150–200 Myr after peak metamorphism, with subsequent slow cooling and denudation rates that are typical of Proterozoic orogens. The apparent absence of orogenic collapse implies that, despite high temperatures and estimated maximum crustal thicknesses comparable to those of large, hot orogens, the THO remained gravitationally stable during its terminal phase.
DS200612-1424
2006
Joyce, S.Thomson, I., Joyce, S.Changing mineral exploration industry approaches to sustainability.SEG 2006 Conference, Wealth Creation in the Minerals Industry, May 14-16, Keystone Colorado USA, Abtract Volume p. 93-95. ( 3p.)GlobalSocial responsibility
DS1997-1153
1997
Joyce, S.A.Thomsom, I., Joyce, S.A.Mineral exploration and the challenge of community relationsá#1Prospectors and Developers Association of Canada (PDAC) Communique, July, 8pLatin America, South America, GlobalMining legislation, legal, community relations, Aboriginal rights, social, political
DS1970-0154
1970
Joynt, R.H.Murray, L.G., Joynt, R.H., O'shea, D.O.C., Foster, R.W., Kleinja.The Geological Environment of Some Diamond Deposits Off The coast of Southwest Africa.Institute of Geological Sciences Report, No. 70/13, PP. 119-142.Southwest Africa, NamibiaGeology, Geomorphology, Diamond Mining Recovery, Littoral Placers
DS1970-0730
1973
Joynt, R.H.Joynt, R.H., Greenshields, R., Hodgen, R.Advances in Sea and Beach Diamond Mining TechniquesMining Engineering Journal of South Africa, Vol. No. APRIL, PP. 25-49.Southwest Africa, NamibiaSubmarine Diamond Placers, Marine Diamond Corporation, Sampling
DS1975-1091
1979
Joynt, R.H.Joynt, R.H.Prospecting and Mining Diamonds from the SeaSth. Afr. Lapidary Journal, Vol. 13, No. 2, PP. 45-46.Southwest Africa, South Africa, NamibiaSubmarine Placers, Diamond Mining Recovery
DS200612-1262
2006
Jozwiak, W.Semenov, V.Y., Jozwiak, W.Lateral variations of the mid-mantle conductance beneath Europe.Tectonophysics, Vol. 416, 1-4, April 5, pp. 279-288.EuropeGeophysics - seismics, geothermometry
DS2001-1055
2001
JPSeyler, M., Toplis, M.J., Lorand, JP, Luquet, CannalClinopyroxene microtextures reveal incompletely extracted melts in abyssalperidotites.Geology, Vol. 29, No. 2, Feb. pp. 155-8.MantlePeridotites
DS1989-0512
1989
J-PGirard, J-P, Deynoux, M., Nahon, D.Diagenesis of the upper Proterozoic siliciclastic sediments of the Taoudeni basin, West Africa, and relation to diabase emplacementJournal of Sedimentary Petrology, Vol. 59, No. 2, March pp. 233-248. Database # 17951West AfricaProterozoic, Diagenesis
DS1993-1638
1993
J-PValet, J-P, Meynadier, L.Geomagnetic field intensity and reversals during the past four millionyears.Nature, Vol. 366, November 18, pp. 234-238.MantlePaleomagnetics, Geophysics -magnetics
DS1995-1250
1995
J-PMilesi, J-P, Egal, E., Ledru, P., Vernhet, Y et al.Les mineralisations du Nord de la Guyana francaise dans leur cadregeologique.Chron. Recherche Min., No. 518, pp. 5-58.French GuianaGeology -3 p. english summary general geology, Metallogeny - mainly gold related
DS200612-0204
2006
J-PCagnard, F., Durrieu, N., Gapais, D., Brun, J-P, Ehlers, C.Crustal thickening and lateral flow during compression of hot lithospheres, with particular reference to Precambrian times.Terra Nova, Vol. 18, Feb. pp. 72-78.MantleGeothermometry
DS201312-0915
2013
J-PTirel, C., Brun, J-P, Burov, E., Wortel, M.J.R., Lebedev, S.A plate tectonics oddity: caterpillar walk exhumation of subducted continental crust.Geology, Vol. 41, 5, pp. 555-558.MantleSubduction
DS1991-1426
1991
Jr.Riley, G.N., Jr., Kohlstedt, D.L.Kinetics of melt migration in upper mantle type rocksEarth and Planetary Science Letters, Vol. 105, pp. 500-521CaliforniaMantle, San Carlos, Melt migration
DS2000-0585
2000
Jratz, K.L.Lorand, J.P., Schmidt, G./, Jratz, K.L.Highly siderophile element geochemistry of the Earth's mantle: new dat a Lanzo and Ronda orogenic peridotiteLithos, Vol. 53, No. 2, Aug. pp.149-64.GlobalPeridotites, Geochemistry
DS200812-0529
2008
Jreige, C.Jreige, C.Discovering a real gem - 3 D modeling helps mine diamonds in Canada.Geo World ( Adams Business Media) Ingenta art 1084185019, Vol. 21, 9, pp. 28-33.CanadaTechnology
DS201510-1789
2015
J-SMoe, K.S., Yang, J-S, Johnson, P., Xu, X., Wang, W.Microdiamonds in chromitite and peridotite. Type 1aB and 1bGSA Annual Meeting, Paper 300-5, 1p. Abstract only BoothRussiaSpectroscopy
DS201711-2521
2017
J-TKang, J-T, Ionov, D.A., Liu, F., Zhang, C-L., Golovin, A.V., Qin, L-P., Zhang, Z-F., Huang, F.Calcium isotopic fractionation in mantle peridotites by melting and metasomatism and Ca isotope composition of the Bulk Silicate Earth.Earth and Planetary Science Letters, Vol. 474, pp. 128-137.Mantleperidotites

Abstract: To better constrain the Ca isotopic composition of the Bulk Silicate Earth (BSE) and explore the Ca isotope fractionation in the mantle, we determined the Ca isotopic composition of 28 peridotite xenoliths from Mongolia, southern Siberia and the Siberian craton. The samples are divided in three chemical groups: (1) fertile, unmetasomatized lherzolites (3.7-4.7 wt.% Al2O3); (2) moderately melt-depleted peridotites (1.3-3.0 wt.% Al2O3) with no or very limited metasomatism (LREE-depleted cpx); (3) strongly metasomatized peridotites (LREE-enriched cpx and bulk rock) further divided in subgroups 3a (harzburgites, 0.1-1.0% Al2O3) and 3b (fertile lherzolites, 3.9-4.3% Al2O3). In Group 1, ?44/40Ca of fertile spinel and garnet peridotites, which experienced little or no melting and metasomatism, show a limited variation from 0.90 to 0.99‰ (relative to SRM 915a) and an average of 0.94 ± 0.05‰ (2SD, ), which defines the Ca isotopic composition of the BSE. In Group 2, the ?44/40Ca is the highest for three rocks with the lowest Al2O3, i.e. the greatest melt extraction degrees (average ‰, i.e. ?0.1‰ heavier than the BSE estimate). Simple modeling of modal melting shows that partial melting of the BSE with ranging from 0.10 to 0.25 can explain the Group 2 data. By contrast, ?44/40Ca in eight out of nine metasomatized Group 3 peridotites are lower than the BSE estimate. The Group 3a harzburgites show the greatest ?44/40Ca variation range (0.25-0.96‰), with ?44/40Ca positively correlated with CaO and negatively correlated with Ce/Eu. Chemical evidence suggests that the residual, melt-depleted, low-Ca protoliths of the Group 3a harzburgites were metasomatized, likely by carbonate-rich melts/fluids. We argue that such fluids may have low (?0.25‰) ?44/40Ca either because they contain recycled crustal components or because Ca isotopes, similar to trace elements and their ratios, may be fractionated by kinetic and/or chromatographic effects of melt percolation in the mantle. The ?44/40Ca in Group 3b lherzolites (0.83-0.89‰) are lower than in the BSE as well, but the effects of metasomatism on ?44/40Ca are smaller, possibly because of the high Ca contents in their protoliths and/or smaller ?44/40Ca differences between the protoliths and metasomatic agents. The BSE estimates based on fertile peridotites in this study fall in the ?44/40Ca ranges for oceanic and continental basalts, various meteorites (achondrites; carbonaceous, ordinary and enstatite chondrites), Mars, and the Moon. These results provide benchmarks for the application of Ca isotopes to planet formation, mantle evolution, and crustal recycling.
DS201709-2078
2017
Ju, Y.Zhu, R-N, Ni, P., Ding, J-Y., Wang, D-Z., Ju, Y., Kang, N.Petrography, chemical composition, and Raman spectra of chrome spinel: constraints on the diamond potential of the no. 30 pipe kimberlite in Wafandian, North Chin a Craton.Ore Geology Reviews, in press available, 40p.Chinadeposit - No. 30 Wafangdian

Abstract: Conventional diamond exploration seldom searches directly for diamonds in rock and soil samples. Instead, it focuses on the search for indicator minerals like chrome spinel, which can be used to evaluate diamond potential. Chrome spinels are preserved as pristine minerals in the early Paleozoic (?465 Ma), hydrothermally altered, Group I No. 30 pipe kimberlite that intruded the Neoproterozoic Qingbaikou strata in Wafangdian, North China Craton (NCC). The characteristics of the chrome spinels were investigated by petrographic observation (BSE imaging), quantitative chemical analysis (EPMA), and Raman spectral analysis. The results show that the chrome spinels are mostly sub-rounded with extremely few grains being subhedral, and these spinels are macrocrystic, more than 500 µm in size. The chrome spinels also have compositional zones: the cores are classified as magnesiochromite as they have distinctly chromium-rich (Cr2O3 up to 66.56 wt%) and titanium-poor (TiO2 < 1 wt%) compositions; and the rims are classified as magnetite as they have chromium-poor and iron-rich composition. In the cores of chrome spinels, compositional variations are controlled by Al3+-Cr3+ isomorphism, which results in a strong Raman spectra peak (A1g mode) varying from 690 cm?1 to 702.9 cm?1. In the rims of chrome spinel, compositional variations result in the A1g peak varying from 660 cm?1 to 672 cm?1. The morphology and chemical compositions indicate that the chrome spinels are mantle xenocrysts. The cores of the spinel are remnants of primary mantle xenocrysts that have been resorbed, and the rims were formed during kimberlite magmatism. The compositions of the cores are used to evaluate the diamond potential of this kimberlite through comparison with the compositions of chrome spinels from the Changmazhuang and No. 50 pipe kimberlites in the NCC. In MgO, Al2O3 and TiO2 versus Cr2O3 plots, the chrome spinels from the Changmazhuang and No. 50 pipe kimberlites are mostly located in the diamond stability field. However, only a small proportion of chrome spinels from No. 30 pipe kimberlite have same behavior, which indicates that the diamond potential of the former two kimberlites is greater than that of the No. 30 pipe kimberlite. This is also supported by compositional zones in the spinel grains: there is with an increase in Fe3+ in the rims, which suggests that the chrome spinels experienced highly oxidizing conditions. Oxidizing conditions may have been imparted by fluids/melts that have a great influence on diamond destruction. Here, we suggest that chrome spinel compositions can be a useful tool for identifying the target for diamond potential in the North China Craton.
DS202004-0503
2020
Juan, A.Chasse, M., Blanchard, M., Cabaret, D., Vantelon, D., Juan, A., Calas, G.First principles modeling of X-ray absorption spectra enlightens the process of scandium sequestration by iron oxides.American Mineralogist, Vol. 105, 7, 10.2138/am-2020-730Globalscandium

Abstract: Scandium is often associated with iron oxides in the environment. Despite the use of scandium as a geochemical tracer and the existence of world-class supergene deposits, uncertainties on speciation obscure the processes governing its sequestration and concentration. Here, we use first-principles approaches to interpret experimental K-edge X-ray absorption near-edge structure spectra of scandium either incorporated in or adsorbed on goethite and hematite, at concentrations relevant for the environment. This modeling helps to interpret the characteristic spectral features, providing key information to determine scandium speciation when associated with iron oxides. We show that scandium is substituted into iron oxides at low concentration without modifying the crystal structure. When scandium is adsorbed onto iron oxide surfaces, the process occurs through outer-sphere complexation with a reduction in the coordination number of the hydration shell. Considering available X-ray absorption spectra from laterites, the present results confirm that scandium adsorption onto iron oxides is the dominant mechanism of sequestration in these geochemical conditions. This speciation explains efficient scandium recovery through mild metallurgical treatments of supergene lateritic ores. The specificities of scandium sorption mechanisms are related to the preservation of adsorbed scandium in million-years old laterites. These results demonstrate the emerging ability to precisely model fine X-ray absorption spectral features of trace metals associated with mineral phases relevant to the environment. It opens new perspectives to accurately determine trace metals speciation from high-resolution spatially-resolved X-ray absorption near-edge structure spectroscopy in order to constrain the molecular mechanisms controlling their dynamics.
DS2003-1448
2003
Juang, W-S.Wang, K.L., O'Reilly, S.Y., Griffin, W.L., Chung, S-L., Juang, W-S.Geochemical characteristics of mantle xenoliths from Penghu Island, Taiwan Straits, SE8 Ikc Www.venuewest.com/8ikc/program.htm, Session 9, POSTER abstractChina, AsiaBlank
DS200412-2081
2003
Juang, W-S.Wang, K.L., O'Reilly, S.Y., Griffin, W.L., Chung, S-L., Juang, W-S.Geochemical characteristics of mantle xenoliths from Penghu Island, Taiwan Straits, SE Asian margin.8 IKC Program, Session 9, POSTER abstractChina, AsiaCraton studies
DS202007-1152
2020
Juarez-Perez, E.Juarez-Perez, E., Haro, M.Perovskite cells take a step forward.Science, Vol 368, 6497, p. 1309.Globalperovskite

Abstract: Today's monocrystalline silicon solar cells have their throne on the roofs of our houses. In the past decade, however, perovskite solar cells (PSCs) show impressive advances with a high power conversion efficiency (PCE) of 25.2% (1) and low fabrication cost, which make this technology promising for further advances in decarbonization energy models (2). Yet the life cycle of PSCs needs to be increased for market integration. Poor stability is the main impediment to commercializing this technology. Thus, great effort has been focused on the causes and mechanisms of degradation, many of which can be mitigated or minimized with encapsulation. Various strategies have been proposed to increase PSCs' operational stability, which is affected by moisture, oxidation, heat, light, and other factors (3, 4). On page 1328 of this issue, Shi et al. (5) report a successful encapsulation procedure for hybrid PSCs.
DS201412-0435
2014
Juchem, P.L.Juchem, P.L., Hinrichs, R., Traverso, M.Analise multi-technicas para identificar diamante e moissanta em joias. 6 Simposio Brasileiro de Geologia do Diamante, Aug. 3-7, 6p. AbstractTechnologyMoissanite
DS1860-0554
1887
Judd, J.W.Judd, J.W.On the Discovery of Leucite in AustraliaMineralogical Magazine., Vol. 7, PP. 194-195.Australia, New South WalesLeucite
DS201605-0852
2016
Judeel, G.Judeel, G., Swaneoel, T., Holder, A., Swarts, B., Van Strijp, T., Cloete, A.Extension of the Culli nan diamond mine No. 1 shaft underneath the existing operating shaft.Diamonds Still Sparkling SAIMM 2016 Conference, Mar. 14-17, pp. 301-316.Africa, South AfricaDeposit - Cullinan
DS201612-2308
2016
Judeel, G.Judeel, G., Swanepoel, T., Holder, A., Swarts, B., van Strijp, T., Cloete, A.Extension of the Culli nan diamond mine no. 1 shaft underneath the existing operating shaft, with emphasis on rock engineering considerations.Journal of South African Institute of Mining and Metallurgy, Vol. 116, Aug. pp. 745-753.Africa, South AfricaDeposit - Cullinan

Abstract: In 2012, Cullinan Diamond Mine began an expansion programme with the shaft deepening and development of access to the C-Cut 1 block at approximately 839 m below surface. The expansion programme is funded by a combination of bank loans and retained operating profit generated by the mine. Continuous production during deepening of the No. 1 Shaft, which is the rock hoisting shaft, was therefore critical for sustainability and efficiency as well as overall funding of the project. The deepening method, support design and verification, as well as learning outcomes pertaining to the extension of the No. 1 Shaft underneath the existing operating shaft are summarized, with emphasis on the importance of gaining some understanding of the shaft's host rock mass.
DS201709-2007
2016
Judeel, G.Judeel, G., Swanepoel, T., Holder, A., Swarts, B., van Strijp, T., Cloete, A.Extension of the Culli nan diamond mine No. 1 shaft underneath the existing operating shaft, with emphasis on rock engineering considerations.South African Institute of Mining and Metallurgy, Vol. 116, 8, pp. 745-752.Africa, South Africadeposit - Cullinan

Abstract: In 2012, Cullinan Diamond Mine began an expansion programme with the shaft deepening and development of access to the C-Cut 1 block at approximately 839 m below surface. The expansion programme is funded by a combination of bank loans and retained operating profit generated by the mine. Continuous production during deepening of the No. 1 Shaft, which is the rock hoisting shaft, was therefore critical for sustainability and efficiency as well as overall funding of the project. The deepening method, support design and verification, as well as learning outcomes pertaining to the extension of the No. 1 Shaft underneath the existing operating shaft are summarized, with emphasis on the importance of gaining some understanding of the shaft's host rock mass.
DS1996-1426
1996
JudgeThompson, P.H., Judge, Charbonneau, Carson, ThomasThermal regimes and diamond stability in the Archean Slave Province northwestern Canadian Shield.Geological Survey of Canada (GSC) Paper, No. 1996-B, pp. 135-46.Northwest TerritoriesGeochronology, Geothermometry
DS1995-1902
1995
Judge, A.S.Thompson, P.H., Judge, A.S., Lewis, T.J.Thermal parameters in rock units of the Winter Lake Lac de Gras area, implications for diamond genesis.Geological Survey of Canada Report of Activities, No. 1995-E, pp. 125-135.Northwest TerritoriesThermal model, Diamond genesis
DS1996-1423
1996
Judge, A.S.Thompson, P.H., Judge, A.S., Charbonneau, B.W., Carson, J.Regional radiogenic heat production and lithospheric temperatures beneath the Slave Province - thickness?northwest Territories Exploration overview 1995, March pp. 3-33-4. abstractNorthwest TerritoriesRadiogenic heat, granites, lithosphere, Kimberlites
DS1996-1424
1996
Judge, A.S.Thompson, P.H., Judge, A.S., Lewis, T.J.Thermal parameters in rock units of the Winter Lake -Lac de Gras-implications for diamond genesis.northwest Territories Exploration overview 1995, March, p. 3-34. abstractNorthwest TerritoriesLithosphere, Geothermometry
DS1996-1425
1996
Judge, A.S.Thompson, P.H., Judge, A.S., Lewis, T.J.Thermal evolution of the lithosphere in the central Slave Province:implications for diamond genesis.Geological Survey of Canada, LeCheminant ed, OF 3228, pp. 151-160.Northwest TerritoriesReflectance data, Thermal history, Slave Province
DS2002-1610
2002
Judge, T.Trench, A., Judge, T.Mineral exploration: what we should look for, where should we look for new deposits, and what should we use in the search?Preview ( Australian Exploration Geophysics Newsletter), Oct. pp. 27-33.AustraliaGeophysics - techniques (not specific to diamonds)
DS1994-0855
1994
Judina, I.A.Judina, I.A.Some features of application of panned concentrate and mineralogic investigation for local prospecting bedrock10th. Prospecting In Areas Of Glaciated Terrain, p. 196-197.. AbstractRussia, White SeaGeochemistry -heavy minerals, Exploration prospecting
DS1900-0257
1904
Judson, J.N.Judson, J.N.Diamond ConcentrationEngineering and Mining Journal, Vol. 77, No. 25, JUNE 23RD. P. 996.Africa, South Africa, United StatesMining Engineering
DS200612-1612
2006
Jue, X.Zhenyu, C., Yuchuan, C., Denghong, W., Jue, X., Jianxiong, Z.Rutiles in eclogites from the Sulu UHPM terrane: a preliminary study.Maor & Bierlein eds. Understanding ore systems through precise geochronology, isotope tracing, microgeochem., Chapter 7-36, pp.861-864.ChinaUHP
DS2000-0419
2000
Juhanoja, J.Holtta, P., Huhma, H., Juhanoja, J.Petrology and geochemistry of mafic granulite xenoliths from the Lahtojoki kimberlite pipe, eastern Finland.Lithos, Vol. 51, No. 1-2, pp. 109-133.FinlandXenoliths
DS2002-1517
2002
Juhas, A.P.Snow, G.G., Juhas, A.P.Trends and forces in mining and mineral explorationSociety of Economic Geologists Special Publication, No.9,pp.1-16.GlobalEconomics - trends, evolutionary, consolidation, Statistics, charts, information, discoveries
DS200712-0497
2007
Juhin, A.Juhin, A., Cabaret, D., Galoisy, L., Hazemann, J-L., Calas, G.First principles investigation of trace element in corporation in minerals: the case of Cr3+ in spinel and pyrope garnet.Frontiers in Mineral Sciences 2007, Joint Meeting of Mineralogical societies Held June 26-28, Cambridge, Abstract Volume p.166-167.TechnologyGarnet mineralogy
DS200712-0498
2007
Juhin, A.Juhin, A., Cabaret, D., Galoisy, L., Hazemann, J-L., Calas, G.First principles investigation of trace element in corporation in minerals: the case of Cr3+ in spinel and pyrope garnet.Frontiers in Mineral Sciences 2007, Joint Meeting of Mineralogical societies Held June 26-28, Cambridge, Abstract Volume p.166-167.TechnologyGarnet mineralogy
DS201910-2249
2019
Juhin, A.Chasse, M., Blanchard, M., Cabareta, D., Juhin, A., Vantelon, D., Griffin, W.L., O'Reilly, S.Y., Calas, G.Deciphering molecular-scale mechanisms covering scandium dynamics in the critical zone. Goldschmidt2019, in press available, 71 ppt.Australialaterites

Abstract: Scandium is often considered as immobile during chemical weathering, based on its low solubility. In contrast to other conservative (i.e. relatively immobile) elements incorporated into accessory minerals resistant to weathering (e.g. zirconium, thorium or niobium), the scarcity of scandium minerals indicates that the processes accounting for scandium's immobilisation are distinctive. However, the evolution of scandium speciation during weathering is unknown, limiting the understanding of the processes controlling its dynamics in the critical zone. Exceptional scandium concentrations in east Australian laterites provide the possibility of unravelling these mechanisms. We follow scandium speciation through thick lateritic profiles (> 30 m) using a multiscale mineralogical and spectroscopic approach involving electron microprobe, laser-ablation--inductively coupled plasma mass spectrometry, selective leaching and X-ray absorption near-edge structure spectroscopy, complemented by mass-transfer calculations. We show that the initial reservoir of scandium contained in the parent rock is preserved under reducing conditions occurring in the lowest horizons of the profiles. The dissolution of scandium-bearing clinopyroxene generates smectitic clays that immobilise and concentrate scandium. It is subsequently trapped in the lateritic duricrust by goethite. Scandium mobilisation appears in this horizon and increases upward as a result of the dissolution of goethite, possibly assisted by dissolved organic matter, and the precipitation of hematite. Molecular-scale analyses demonstrate that changes in speciation govern scandium dynamics, with substitution in smectitic clays and adsorption on iron oxyhydroxides playing a crucial role in scandium immobility in the saprolite and lower lateritic duricrust. The higher affinity of scandium for goethite relative to hematite drives scandium mobilisation in the upper lateritic duricrust, leading to its concentration downward in the lower lateritic duricrust. These successive mechanisms illustrate how the unique complexity of the critical zone leads to scandium concentrations that may form new types of world-class scandium deposits. Comparison with conservative elements and with rare-earth elements, expected to have similar geochemical properties, emphasizes the unique behaviour of scandium in the critical zone. While scandium remains immobile during the early stages of weathering, intense and long-term alteration processes, observed in lateritic contexts, lead to scandium mobilisation. This study highlights the dependence of scandium mobility on weathering conditions.
DS2002-0484
2002
JuhlinFriberg, M., Juhlin, Beckolmen, Petrov, GreenPaleozoic tectonic evolution of the Middle Urals in the light of ESRU seismic experiment.Journal of the Geological Society of London, Vol.159,3,pp.295-306., Vol.159,3,pp.295-306.Russia, UralsTectonics
DS2002-0485
2002
JuhlinFriberg, M., Juhlin, Beckolmen, Petrov, GreenPaleozoic tectonic evolution of the Middle Urals in the light of ESRU seismic experiment.Journal of the Geological Society of London, Vol.159,3,pp.295-306., Vol.159,3,pp.295-306.Russia, UralsTectonics
DS1995-0899
1995
Juhlin, C.Juhlin, C., Kashubin, S., Knapp, J.H., Makovsky, RybergProject conducts seismic reflection profiling in the Ural MountainsEos, Vol. 76, No. 19, May 9, p. 193, 197, 198, 199.Russia, UralsTectonics, Geophysics -seismics
DS1998-0710
1998
Juhlin, C.Juhlin, C., Friberg, M., Echtler, et al.Crustal structure of the Middle Urals: results from the ESRU Europrobe seismic reflection profiling in Urals...Tectonics, Vol. 17, No. 5, Oct. pp. 710-725.Russia, UralsGeophysics - seismics, East European Craton, tectonics
DS1998-0711
1998
Juhlin, C.Juhojuntti, N., Juhlin, C.Seismic lower crustal activity and signal penetration in the Siljan Ringarea, Central Sweden.Tectonophysics, Vol. 288, No. 1-4, Mar. pp. 17-30.SwedenTectonics, Geophysics - seismic
DS1999-0344
1999
Juhlin, C.Juhlin, C., Palm, H.3 D structure below Avro Island from high resolution reflection seismicstudies, southeastern Sweden.Geophysics, Vol. 64, No. 3, May-June pp. 662-667.SwedenGeophysics - seismics, Tectonics - not specific to diamonds
DS2000-0045
2000
Juhlin, C.Ayarza, P., Brown, D., Juhlin, C.Contrasting tectonic history of arc-continent suture in southern and middle Urals: evolution of orogen.Journal of Geological Society of London, Vol. 157, No. 5, Sept.pp.1065-76.Russia, UralsTectonics, Orogeny
DS2000-0302
2000
Juhlin, C.Friberg, M., Juhlin, C., Green, A.G., Hortsmeyer, RothEuroprobe seismic reflection profiling across the eastern middle Urals and West Siberian Basin.Terra Nova, Vol. 12, No. 6, Dec.pp. 252-7.Urals, Russia, SiberiaGeophysics - seismics
DS2000-0458
2000
Juhlin, C.Juhlin, C., Wahlgren, C.H., Stephens, M.B.Seismic imaging in the frontal part of the Sveconorwegian Orogen, south western Sweden.Precambrian Research, Vol. 102, No. 1-2, July 1, pp. 135-SwedenGeophysics - seismics, Orogen - Sveconorowegian
DS2001-0554
2001
Juhlin, C.Juhojuntti, N., Juhlin, C.Crustal reflectivity underneath the Central Scandinavian CaledonidesTectonophysics, Vol. 334, No. 3-4, pp. 191-210.Scandinavia, Norway, Sweden, Denmark, FinlandGeophysics - seismics
DS2002-0211
2002
Juhlin, C.Brown, D., Juhlin, C., Puchkov, V.Mountain building in the Uralides ... Pangea to the presentAmerican Geophysical Union, Geophysical Monograph, No. 132, 300p.Russia, Europe, UralsBook - Tectonics, arc collision, crustal, orogenesis, Geochronology
DS2002-0791
2002
Juhlin, C.Juhlin, C., Elming, S.A., Mellqvist, C., Ohlander, B., Weihed, P., Wikstrom, A.Crustal refectivity near Archean Proterozoic boundary in northern Sweden andGeophysical Journal International, Vol.150,1,pp.180-197.SwedenGeophysics - seismics, Boundary
DS200412-0137
2004
Juhlin, C.Bergman, B., Tryggvason, A., Juhlin, C.High resolution seismic traveltime tomography incorporating static corrections applied to a till covered bedrock environment.Geophysics, Vol. 69, 4, pp. 1082-1090.Europe, SwedenGeomorphology - tomography
DS200412-0223
2002
Juhlin, C.Brown, D., Juhlin, C., Puchkov, V.Mountain building in the Uralides ... Pangea to the present.American Geophysical Union, Geophysical Monograph, No. 132, 300p.Russia, Europe, UralsBook - Tectonics, arc collision, crustal, orogenesis Geochronology
DS200612-0176
2006
Juhlin, C.Brown, D., Juhlin, C.A possible lower crustal flow channel in the Middle Urals based on reflection seismic data.Terra Nova, Vol. 18, 1, Feb. pp. 1-8.Russia, UralsGeophysics - seismics
DS200612-0177
2006
Juhlin, C.Brown, D., Juhlin, C., Tryggvason, A., Friberg, M., Rybalka, A., Puchkov, V.Structural architecture of the southern and middle Urals foreland from reflection seismicsTectonics, Vol. 25, 1, Jan. TC1002RussiaTectonics
DS200712-0116
2006
Juhlin, C.Brown, D., Spadea, P., Puchkov, V., Alvarez-Marron, J., Herrington, R., Willner, A.P., Hetzel, R., Gorozhanina, Y., Juhlin, C.Arc continent collision in the southern Urals.Earth Science Reviews, in press availableRussia, UralsBaltica tectonics, UHP, geochemistry
DS1998-0711
1998
Juhojuntti, N.Juhojuntti, N., Juhlin, C.Seismic lower crustal activity and signal penetration in the Siljan Ringarea, Central Sweden.Tectonophysics, Vol. 288, No. 1-4, Mar. pp. 17-30.SwedenTectonics, Geophysics - seismic
DS2001-0554
2001
Juhojuntti, N.Juhojuntti, N., Juhlin, C.Crustal reflectivity underneath the Central Scandinavian CaledonidesTectonophysics, Vol. 334, No. 3-4, pp. 191-210.Scandinavia, Norway, Sweden, Denmark, FinlandGeophysics - seismics
DS1991-0406
1991
Juigali, J.Duckworth, K., Calvert, H.T., Juigali, J.A method for obtaining depth estimates from the geometry of SlingramprofilesGeophysics, Vol. 56, No. 10, October, pp. 1543-1552GlobalGeophysics -electromagnetics, Overburden, host rock
DS1994-0856
1994
Juilland, J.Juilland, J.Biodiversity-ecosystem-energy and mineral resources on public landsAmerican Institute of Mining, Metallurgical, and Petroleum Engineers (AIME) Preprint, Meeting held Albuquerque Feb. 14-17th, No. 94-191, 2pUnited StatesBLM management, Environmental
DS201212-0204
2012
JuliFlor De Lis, M., Stitch, Morales, Juli, Diaz, Cordoba, Pulgar, Ibarra, Harnafi, Gonzalez-LodeiroCrustal thickness variations in northern Morocco.Journal of Geophysical Research, Vol. 117, B2, B02312.Africa, MoroccoGeophysics - seismics
DS200812-0530
2008
Julia, J.Julia, J., Assumpcao, M., Rocha, M.P.Deep crustal structure of the Parana Basin from receiver functions and Rayleigh wave dispersion: evidence for a fragmented cratonic root.Journal of Geophysical Research, Vol. 113, B8318.South America, BrazilGeophysics - seismics
DS201212-0738
2012
Julia, J.Tugume, F., Nyblade, A., Julia, J.Moho depths and Poisson's ratios of Precambrian crust in East Africa: evidence for similarities in Archean and Proterozoic crustal structure.Earth and Planetary Science Letters, Vol. 355-356, pp. 73-81.Africa, East AfricaTectonics
DS201312-0036
2013
Julia, J.Assumpcao, M., Bianchi, M., Julia, J., Dias, F.L., Nascimento, R., Drouet, S., Pavao, C.G., Albuquerque, D.F., Lopes, A.E.V.Crustal thickness map of Brazil: dat a compilation and main features.Journal of South American Earth Sciences, Vol. 609, pp. 82-96.South America, BrazilMOHO map
DS201312-0037
2013
Julia, J.Assumpcao, M., Feng, M., Tassara, A., Julia, J.Models of crustal thickness for South America from seismic refraction, receiver functions and surface wave tomography.Tectonophysics, in press available 15p.South AmericaGeophysics - seismics - boundary
DS201902-0289
2018
Julia, J.Lamarque, G., Agostinetti, N.P., Julia, J., Evain, M.Joint interpretation of SKS-splitting measurements and receiver function data for detecting seismic anisotropy in the upper mantle: feasibility and limitations.AGU, 1p. abstract Mantlegeophysics -seismic

Abstract: Measuring seismic anisotropy within the Earth is essential as it constitutes a proxy for inferring upper mantle deformation related to mantle flow, that develops preferred orientations of the minerals in response to tectonic strain. The most-used method to detect anisotropy beneath a seismic station is the measurement of teleseismic SKS wave splitting on two horizontal recordings, i.e. measuring the delay time (?t) between two fast- and slow- polarized shear-waves and the orientation of polarization (?). This technique allows a integrative measurement (SKS data, hereinafter) that estimates the average ? and ?t along the entire SKS ray-path. Despite its importance for large-scale anisotropy within the upper mantle, the analysis of SKS data suffers from several limitations : (1) SKS data become difficult to interpret in regions where several anisotropic layers occur; (2) SKS waves fail to provide robust information about anisotropy related to thin layers; and (3) SKS data can investigate rock volumes with an horizontal symmetry axis only. During the last decade a new method, called harmonic decomposition of teleseismic Receiver Functions (RFs) has been developed in order to detect more complex anisotropic layering. This methodology is based on the extraction of back-azimuth harmonics of the RF dataset. Briefly, it constitutes a tool to appreciate the value of ? and ?t at every depth-level affording a detailed study of the rock anisotropy with both plunging and horizontal symmetry axis. RFs studies are however commonly limited to the first 10-15s of the signal and do not sample the deepest anisotropy. In this work we investigate in details both SKS data and RFs harmonic decomposition for a pool of stations deployed in northeastern Brasil, in order to understand how results from the analysis of these two observables can be jointly interpreted. We focus our study on the permanent station RCBR and on temporary seismic stations deployed in the area. We show that comparison and/or joint interpretation is not straightforward as both results can vary according to the amount of data available and their distribution in back-azimuth, and filtering. However, tacking into account those issues, the integration of these two observables represent a great step-forward for robust detection of upper mantle anisotropy.
DS1991-0813
1991
Julian, B.Julian, B., Zidek, J.Field guide to geologic excursions in New Mexico and adjacent areas of Texas and ColoradoNew Mexico Bureau of Mines, Bulletin. No. 137, 192p. $ 14.00New Mexico, Texas, ColoradoGuidebook, Volcanics -general
DS2002-0792
2002
Julian, B.Julian, B.Seismological detection of slab metamorphismScience, No.5573, May 31, pp.1625-6.MantleGeophysics - seismics
DS2003-0418
2003
Julian, B.R.Foulger, G.R., Du, Z., Julian, B.R.Iclandic type crustGeophysical Journal International, IcelandBlank
DS200412-0570
2003
Julian, B.R.Foulger, G.R., Du, Z., Julian, B.R.Iclandic type crust.Geophysical Journal International, Vol. 155, pp. 567-590.Europe, IcelandGeophysics - seismics, mantle, plume
DS200512-0490
2005
Julian, B.R.Julian, B.R.What can seismology say about hotspots?Plates, Plumes, and Paradigms, pp. 155-170. ( total book 861p. $ 144.00)GlobalGeophysics - seismics
DS200512-0491
2005
Julian, B.R.Julian, B.R., Evans, J.R.Guided seismic waves: possible mantle plume diagnostics.Chapman Conference held in Scotland August 28-Sept. 1 2005, 1p. abstractMantleMantle plume, geophysics - seismics
DS201312-0273
2013
Julian, B.R.Foulger, G.R., Panza, G.F., Artemieva, I.M., Bastow, I.D., Cammarano, F., Evans, J.R., Hamilton, W.B., Julian, B.R., Lustrino, M., Thybo, H., Yanovskaya, T.B.Caveat on tomographic images.Terra Nova, Vol. 25, 4, pp. 259-281.MantleSeismic tomography, geodynamics
DS201511-1847
2015
Julian, B.R.Julian, B.R., Foulger, G.R., Hatfield, O., Jackson, S.E., Simpson, E., Einbeck, J., Moore, A.Hotspots in hindsight. Mentions kimberlitesGeological Society of America Special Paper, No. 514, pp. SPE514-08.MantleHotspots

Abstract: Thorne et al. (2004), Torsvik et al. (2010; 2006) and Burke et al. (2008) have suggested that the locations of melting anomalies ("hot spots") and the original locations of large igneous provinces ("LIPs") and kimberlite pipes, lie preferentially above the margins of two "large lower-mantle shear velocity provinces", or LLSVPs, near the bottom of the mantle, and that the geographical correlations have high confidence levels (> 99.9999%) (Burke et al., 2008, Fig. 5). They conclude that the LLSVP margins are "Plume-Generation Zones", and that deep-mantle plumes cause hot spots, LIPs, and kimberlites. This conclusion raises questions about what physical processes could be responsible, because, for example, the LLSVPs are apparently dense and not abnormally hot (Trampert et al., 2004). The supposed LIP-hot spot-LLSVP correlations probably are examples of the "Hindsight Heresy" (Acton, 1959), of performing a statistical test using the same data sample that led to the initial formulation of a hypothesis. In this process, an analyst will consider and reject many competing hypotheses, but will not adjust statistical assessments correspondingly. Furthermore, an analyst will test extreme deviations of the data, , but not take this fact into account. "Hindsight heresy" errors are particularly problematical in Earth science, where it often is impossible to conduct controlled experiments. For random locations on the globe, the number of points within a specified distance of a given curve follows a cumulative binomial distribution. We use this fact to test the statistical significance of the observed hot spot-LLSVP correlation using several hot-spot catalogs and mantle models. The results indicate that the actual confidence levels of the correlations are two or three orders of magnitude smaller than claimed. The tests also show that hot spots correlate well with presumably shallowly rooted features such as spreading plate boundaries. Nevertheless, the correlations are significant at confidence levels in excess of 99%. But this is confidence that the null hypothesis of random coincidence is wrong. It is not confidence about what hypothesis is correct. The correlations probably are symptoms of as-yet-unidentified processes.
DS1996-0704
1996
Julian Kruttschmitt Mineral Research CentreJulian Kruttschmitt Mineral Research CentreMining and mineral processing textsJkmrc., AustraliaBook - ad, Mineral processing
DS201903-0500
2019
Juliani, C.Carneiro, C.de C., Juliani, C., Carreiro-Araujo, S.A., Monteiro, L.V.S., Crosta, A.P., Fernandes, C.M.D.New crustal framework in the Amazon craton based on geophysical data: evidence of deep east-west trending suture zones.IEEE.org , Vol. 16, 1, pp. 20-24.South America, Brazilcraton

Abstract: The Tapajós mineral province (TMP), in the Brazilian Amazon Craton, comprises NW-SE Paleoproterozoic insular magmatic arcs accreted to the Carajás Archean Province (CAP). We present new geological and geophysical data pointing toward a different evolutionary model for the TMP. Results obtained from magnetic data indicate that NNW-SSE trending structures occur at shallow crustal levels. Furthermore, an E-W structural framework shows up at 15.4 km depth, in disagreement with the accreted island arc orientation. These E-W structures are associated with north-dipping blocks, reflecting ductile compressive tectonics, similar to the tectonic setting found in the CAP. We interpret these E-W structures of the TMP as the continuity westwards of similar structures from the CAP, under the Paleoproterozoic volcanic rocks of the Uatumã Supergroup. Based on this evidence, we propose that Paleoproterozoic arcs have been formed in an Archean active continental margin, instead of in island arcs. This novel tectonic setting for the TMP has significant implications for the tectonic evolution and the metallogenic potential of the southern portion of the Amazon craton, particularly for Paleoproterozoic magmatic-hydrothermal (epithermal and porphyry) precious and base metal systems.
DS201903-0541
2019
Juliani, C.Roverato, M., Giordano, D., Giovanardi, T., Juliani, C., Polo, L.The 2.0-1.88 Ga Paleoproterozoic evolution of the southern Amazonian Craton ( Brazil): an interpretation inferred by lithofaciological, geochemical and geochronological data.Gondwana Research, Vol. 70, pp. 1-24. doi:10.1016/ j.gr.2018.12.005South America, Brazilcraton

Abstract: The study of Paleoproterozoic rocks is crucial for understanding Earth's tectonic evolution during the time when most of the modern crust and ore deposits were formed. The rocks of the Brazilian Amazonian Craton record some of the most-complete and best-preserved Paleoproterozoic magmatic and volcanic episodes on Earth. Following previous investigations, we present new lithofaciological and stratigraphic records of the felsic rocks of the Tapajós Mineral Province (TMP) (~2-1.88?Ga) and the São Felix do Xingú region (SFX) (~1.88?Ga) which, combined with new petrological and geochronological data, help providing a more complete understanding of the tectonic, magmatic and volcanological evolution of the Amazonian Craton. This magmatism/volcanism is thought to be formed in a late-/post-orogenic to extentional regime confirmed by the new geochemical data presented here. The transition from late-convergent to extensional tectonic setting could register the beginning of the taphrogenesis that marked the Amazonian Craton throughout the Mesoproterozoic. The volcanological approach of this contribution can serve as a strategy for the modelling of the evolution of Precambrian volcano-sedimentary basins around the world. The large amount of rocks analyzed are divided into primary and secondary volcaniclastic products depending on if they resulted from a direct volcanic activity (pyroclastic) or processes that reworked pyroclastic fragments. Furthermore, the deposits are subdivided into massive and stratified, depending on their primary mechanisms of transport and emplacement. By confirming the results from previous studies, our study permits to depict a more precise paleo-environmental picture of the processes that occurred in the Amazonian Craton during the Late-Paleoproterozoic. In particular, the presence of large regional-scale fissural systems and caldera collapses produced large silicic explosive volcanic eruptions, also accompanied by the emission of large volume effusive products. Although studies on the Amazonian Craton are still scarce and controversial, the present study provides new evidence that this volcanism may have formed one of the largest Silicic Large Igneous Provinces (SLIP) on earth. Our data also confirm that at least two major Paleoproterozoic periods of formation of volcanic rocks exist in the Amazonian craton. This point is of great relevance for any future interpretation of the geological evolution of this craton.
DS201905-1074
2019
Juliani, C.Roverato, M., Giordano, D., Giovanardi, T., Juliani, C., Polo, L.The 2.0-1.88 Ga Paleoproterozoic evolution of the southern Amazonian Craton ( Brazil): an interpretation inferred by lithofaciological, geochemical and geochronological data.Gondwana Research, Vol. 70, pp. 1-24.South America, Brazilcraton

Abstract: The study of Paleoproterozoic rocks is crucial for understanding Earth's tectonic evolution during the time when most of the modern crust and ore deposits were formed. The rocks of the Brazilian Amazonian Craton record some of the most-complete and best-preserved Paleoproterozoic magmatic and volcanic episodes on Earth. Following previous investigations, we present new lithofaciological and stratigraphic records of the felsic rocks of the Tapajós Mineral Province (TMP) (~2-1.88?Ga) and the São Felix do Xingú region (SFX) (~1.88?Ga) which, combined with new petrological and geochronological data, help providing a more complete understanding of the tectonic, magmatic and volcanological evolution of the Amazonian Craton. This magmatism/volcanism is thought to be formed in a late-/post-orogenic to extentional regime confirmed by the new geochemical data presented here. The transition from late-convergent to extensional tectonic setting could register the beginning of the taphrogenesis that marked the Amazonian Craton throughout the Mesoproterozoic. The volcanological approach of this contribution can serve as a strategy for the modelling of the evolution of Precambrian volcano-sedimentary basins around the world. The large amount of rocks analyzed are divided into primary and secondary volcaniclastic products depending on if they resulted from a direct volcanic activity (pyroclastic) or processes that reworked pyroclastic fragments. Furthermore, the deposits are subdivided into massive and stratified, depending on their primary mechanisms of transport and emplacement. By confirming the results from previous studies, our study permits to depict a more precise paleo-environmental picture of the processes that occurred in the Amazonian Craton during the Late-Paleoproterozoic. In particular, the presence of large regional-scale fissural systems and caldera collapses produced large silicic explosive volcanic eruptions, also accompanied by the emission of large volume effusive products. Although studies on the Amazonian Craton are still scarce and controversial, the present study provides new evidence that this volcanism may have formed one of the largest Silicic Large Igneous Provinces (SLIP) on earth. Our data also confirm that at least two major Paleoproterozoic periods of formation of volcanic rocks exist in the Amazonian craton. This point is of great relevance for any future interpretation of the geological evolution of this craton.
DS201908-1808
2019
Juliani, C.Roverato, M., Giordano, D., Giovanardi, T., Juliani, C., Polo, L.The 2.0-1.88 Ga Paleoproterozoic evolution of the southern Amazonian craton ( Brazil): an interpretation inferred by lithofaciological, geochemical and geochronological data.Gondwana Research, Vol. 70, pp. 1-24.South America, Braziltectonics

Abstract: The study of Paleoproterozoic rocks is crucial for understanding Earth's tectonic evolution during the time when most of the modern crust and ore deposits were formed. The rocks of the Brazilian Amazonian Craton record some of the most-complete and best-preserved Paleoproterozoic magmatic and volcanic episodes on Earth. Following previous investigations, we present new lithofaciological and stratigraphic records of the felsic rocks of the Tapajós Mineral Province (TMP) (~2-1.88?Ga) and the São Felix do Xingú region (SFX) (~1.88?Ga) which, combined with new petrological and geochronological data, help providing a more complete understanding of the tectonic, magmatic and volcanological evolution of the Amazonian Craton. This magmatism/volcanism is thought to be formed in a late-/post-orogenic to extentional regime confirmed by the new geochemical data presented here. The transition from late-convergent to extensional tectonic setting could register the beginning of the taphrogenesis that marked the Amazonian Craton throughout the Mesoproterozoic. The volcanological approach of this contribution can serve as a strategy for the modelling of the evolution of Precambrian volcano-sedimentary basins around the world. The large amount of rocks analyzed are divided into primary and secondary volcaniclastic products depending on if they resulted from a direct volcanic activity (pyroclastic) or processes that reworked pyroclastic fragments. Furthermore, the deposits are subdivided into massive and stratified, depending on their primary mechanisms of transport and emplacement. By confirming the results from previous studies, our study permits to depict a more precise paleo-environmental picture of the processes that occurred in the Amazonian Craton during the Late-Paleoproterozoic. In particular, the presence of large regional-scale fissural systems and caldera collapses produced large silicic explosive volcanic eruptions, also accompanied by the emission of large volume effusive products. Although studies on the Amazonian Craton are still scarce and controversial, the present study provides new evidence that this volcanism may have formed one of the largest Silicic Large Igneous Provinces (SLIP) on earth. Our data also confirm that at least two major Paleoproterozoic periods of formation of volcanic rocks exist in the Amazonian craton. This point is of great relevance for any future interpretation of the geological evolution of this craton.
DS1900-0767
1909
Julien, A.A.Julien, A.A.A Bibliography of the Diamond Fields of South AfricaEconomic Geology, Vol. 5, PP. 453-469.Africa, South AfricaBibliography
DS200612-0649
2006
Jull, A.J.T.Jull, A.J.T., Burr, G.S.Accelerator mass spectrometry: is the future bigger or smaller?Earth and Planetary Science Letters, Vol. 243, 3-4, March 30, pp. 305-325.TechnologySpectrometry
DS1998-1356
1998
Jull, M.Slater, L., Jull, M., Gronvold, K.Deglaciation effects on mantle melting under Iceland: results from the northern volcanic zone.Earth and Planetary Science Letters, Vol.164, No.1-2, Dec.15, pp.151-78.GlobalGeomorphology, Mantle hot spots
DS2001-0555
2001
Jull, M.Jull, M., Kelemen, P.B.On the conditions for lower crustal convective instabilityJournal of Geophy. Res., Vol. 106, No. 4, Apr. 10, pp. 6423-46.MantleGeophysics, Convection
DS201904-0776
2019
Jumar, V.P.Saikia, U., Jumar, V.P., Rai, S.S.Complex upper mantle deformation beneath the Dharwar craton inferred from high density splitting measurements: distinct lateral variation from west to east.Tectonophysics, Vol. 755, pp. 10-20.Indiageophysics - seismics

Abstract: Upper mantle anisotropy investigated using 172 core-refracted (SKS, SKKS) seismic phases along a ~660?km long profile at 10 to 20?km intervals from the west to the east coast of South India reveals significant lateral variations in its magnitude and direction. This profile, with 38 broadband seismic stations, covers mid-Archean Western Dharwar craton (WDC), late-Archean Eastern Dharwar Craton (EDC), Proterozoic Cuddapah Basin (CB) and the passive continental margins along the west and east coast. The observed fast polarization directions (FPDs) show lateral variability: NW50o to NW5o beneath the WDC, NW40o to NE30o beneath the EDC and N5o to N85o beneath the CB and further east. The delay time varies between 0.4 and 2.0?s with an average of 1?s. However, we are unable to fit a two layers anisotropy model for the region due to sparse azimuth coverage. Beneath the WDC, the direction of the fast axis follows trends of shear zones and faults, suggesting “frozen-in” anisotropy in the lithosphere, possibly established during the lithospheric evolution in mid-late Archean. In the EDC, the fast axis does not only follow the plate motion direction but it deviates, manifesting late Archean to Proterozoic deformation may still be present as fossil mantle anisotropy. The splitting trend beneath the CB and Eastern Ghat (EG) follows the strike of the rift along with plate motion direction, indicating anisotropy is influenced by the combination of “frozen” anisotropy due to continental rifting along the eastern margin of Indian plate and active asthenospheric flow.
DS2003-0109
2003
Jun, S.Bielinski, R.A., Park, S.K., Rybin, A., Batalev, V., Jun, S., Sears, C.Lithospheric heterogeneity in the Kyrgyz Tien Shan imaged by magnetotelluric studiesGeophysical Research Letters, Vol. 30, No. 15, Aug. 1, DOI 10.1029/2003GLO17455ChinaGeophysics - tellurics
DS200412-0152
2003
Jun, S.Bielinski, R.A., Park, S.K., Rybin, A., Batalev, V., Jun, S., Sears, C.Lithospheric heterogeneity in the Kyrgyz Tien Shan imaged by magnetotelluric studies.Geophysical Research Letters, Vol. 30, no. 15, Aug. 1, DOI 10.1029/2003 GLO17455ChinaGeophysics - tellurics
DS201012-0895
2010
Jun, S.Zhonghua, S., Taijin, L., Mendong, S., Jun, S., Jing, D., Xihuan, Z.2010 coated and fracture filled coloured diamond.The Australian Gemmologist, Vol. 24, 1,TechnologyDiamond filling
DS201212-0832
2011
Jun, S.Zhonghua, S., Taijin, L., Meidong, S., Jun, S., Jingjing, S.High quality synthetic yellow orange diamond emerges in China.The Australian Gemmologist, Vol. 24, 7, July-Sept pp.TechnologySynthetics
DS201511-1894
2014
Jun, S.Zhonghua, S., Taijin, L., Meidong, S., Jun, S., Jing, D., Xikuan, Z.Coated and fracture filled coloured diamond.Australian Gemmologist, Vol. 24, 2, pp. 41-43.TechnologyDiamond morphology
DS201511-1895
2014
Jun, S.Zhonghua, S., Taijin, L., Meidong, S., Jun, S., Jingjing, S.High quality synthetic yellow orange diamond emerges in China.Australian Gemmologist, Vol. 24, 7, pp. 167-170.ChinaSynthetics
DS201810-2334
2018
Juncker, C.Juncker, C., Herreweghe, A., DeLaunay, A.Les diamants de Golconde.Revue de Gemmologie A.F.G. IN: French, No. 202, pp. 22-26Indiahistory
DS201312-0888
2013
Jung, D.Sturm, S., Wulf, G., Jung, D., Kenmann, T.The Ries impact, a double layerGeology, Vol. 41, 5, pp. 531-534.Europe, GermanyImpact Crater
DS201112-0487
2011
Jung, D.Y.Jung, D.Y., Schmidt, M.W.Solid solution behaviour of CaSiO3 and MgSiO3 perovskites.Physics and Chemistry of Minerals, Vol. 38, 4, pp. 311-319.MantleInterior structure
DS1998-0721
1998
Jung, H.Karato, S.I., Jung, H.Water, partial melting and the origin of the seismic low velocity and high attenuation zone in Upper Mantle.Earth and Planetary Science Letters, Vol. 157, No. 3-4, Apr. 30, pp. 193-208.MantleGeophysics - seismics, Melting
DS200812-0544
2008
Jung, H.Karato, S-I., Jung, H., Katayama, I., Skemer, P.Geodynamic significance of seismic anisotropy of the upper mantle: new insights from laboratory studies.Annual Review of Earth and Planetary Sciences, Vol. 36, pp. 59-95.MantleGeophysics - seismic anistropy
DS200912-0347
2009
Jung, H.Jung, H., Mo, W., Green, H.W.Upper mantle seismic anisotropy resulting from pressure induced slip transition in olivine.Nature Geoscience, Vol. 2, 1, pp. 73-77.MantleAnisotropy
DS201112-0141
2011
Jung, H.Cao, Y., Song, S.G., Niu, Y.L., Jung, H., Jin, Z.M.Variation of mineral composition, fabric and oxygen fugacity from massive to foliated eclogites during exhumation of subducted ocean crust in North Qiilian sutureJournal of Metamorphic Geology, Vol. 29, 7, pp. 699-720.ChinaSubduction
DS201112-0768
2011
Jung, H.Park, M., Jung, H.Microstructure of Yuka eclogite, North Qaidam HP UHP terrane northwestern China.Goldschmidt Conference 2011, abstract p.1598.ChinaUHP
DS201112-0816
2011
Jung, H.Potgeiter, J., Sommer, H., Regenauer-Lieb, K., Jung, H., Gasharova, B.The formation of microdiamonds in cracks caused by C-O-H rich fluid under medium to low pressure conditions.Goldschmidt Conference 2011, abstract p.1662.Africa, South AfricaVictor
DS201112-0836
2011
Jung, H.Purchase, M., Sommer, H., Regenauer-Lieb, K., Jung, H., Gasharova, B.Coexistent aqueous fluid phase and melt in lherzolites from Bultfontein, South Africa.Goldschmidt Conference 2011, abstract p.1675.Africa, South AfricaDeposit - Bultfontein
DS201112-0986
2011
Jung, H.Sommer, H., Regenauer-Lieb, K., Gaede, O., Jung, H., Gasharova, B.WEERTMAN cracks: a possible mechanism for near sonic speed diamond extraction from the Earth's mantle.Goldschmidt Conference 2011, abstract p.1908.MantleTransport for diamond bearing kimberlite melts
DS201212-0692
2012
Jung, H.Sommer, H., Regenauer-Lieb, K., Gasharova, B., Jung, H.The formation of volcanic centers at the Colorado Plateau as a result of the passage of aqueous fluid through the oceanic lithospher and the subcontinental mantle" new implications for the planetary water cycle in the western United States.Journal of Geodynamics, Vol. 61, Oct. pp. 154-171.United States, Colorado PlateauVolcanism
DS201502-0072
2015
Jung, H.Lee, J., Jung, H.Lattice- preferred orientation of olivine found in diamond bearing garnet peridotites in Finsch, South Africa and implications for seismic anisotropy.Journal of Structural Geology, Vol. 70, Jan. pp. 12-22.Africa, South AfricaDeposit - Finsch
DS202010-1831
2020
Jung, H.Cao, Y., Jung, H., Ma, J.Seismic properties of a unique olivine-rich eclogite in the western Gneiss region, Norway.Minerals ( MDPI), 10.339/min10090774 22p. PdfEurope, Norwayeclogites

Abstract: Investigating the seismic properties of natural eclogite is crucial for identifying the composition, density, and mechanical structure of the Earth’s deep crust and mantle. For this purpose, numerous studies have addressed the seismic properties of various types of eclogite, except for a rare eclogite type that contains abundant olivine and orthopyroxene. In this contribution, we calculated the ambient-condition seismic velocities and seismic anisotropies of this eclogite type using an olivine-rich eclogite from northwestern Flemsøya in the Nordøyane ultrahigh-pressure (UHP) domain of the Western Gneiss Region in Norway. Detailed analyses of the seismic properties data suggest that patterns of seismic anisotropy of the Flem eclogite were largely controlled by the strength of the crystal-preferred orientation (CPO) and characterized by significant destructive effects of the CPO interactions, which together, resulted in very weak bulk rock seismic anisotropies (AVp = 1.0-2.5%, max. AVs = 0.6-2.0%). The magnitudes of the seismic anisotropies of the Flem eclogite were similar to those of dry eclogite but much lower than those of gabbro, peridotite, hydrous-phase-bearing eclogite, and blueschist. Furthermore, we found that amphibole CPOs were the main contributors to the higher seismic anisotropies in some amphibole-rich samples. The average seismic velocities of Flem eclogite were greatly affected by the relative volume proportions of omphacite and amphibole. The Vp (8.00-8.33 km/s) and Vs (4.55-4.72 km/s) were remarkably larger than the hydrous-phase-bearing eclogite, blueschist, and gabbro, but lower than dry eclogite and peridotite. The Vp/Vs ratio was almost constant (avg. ? 1.765) among Flem eclogite, slightly larger than olivine-free dry eclogite, but similar to peridotite, indicating that an abundance of olivine is the source of their high Vp/Vs ratios. The Vp/Vs ratios of Flem eclogite were also higher than other (non-)retrograded eclogite and significantly lower than those of gabbro. The seismic features derived from the Flem eclogite can thus be used to distinguish olivine-rich eclogite from other common rock types (especially gabbro) in the deep continental crust or subduction channel when high-resolution seismic wave data are available.
DS201912-2791
2019
Jung, J.Jung, J.Diavik diamond mine A21 orebody.Yellowknife Forum NWTgeoscience.ca, abstract volume p. 90.Canada, Northwest Territoriesdeposit - Diavik

Abstract: Diavik’s newest orebody, the A21 kimberlite pipe, was brought into production in December 2017 when surface mining began. This is the fourth kimberlite pipe to be mined at the Diavik Diamond Mine, located at Lac de Gras, 300 kilometres northeast of Yellowknife. To access this underwater orebody, Diavik constructed an engineered, 2.1 km long rock fill water retention dike during 2014 to 2017. This has now opened up the opportunity to study and evaluate possible mining methods below the open pit. Such additional kimberlite extraction would occur from 2023 to 2025.
DS1994-1896
1994
Jung, K.Weiller, M., Sattel, S., Jung, K., Ehrhardt, H.Is C(60) fullerite harder than diamondPhys. Lett. A., Vol. 188, No. 3, May 23, pp. 281-286.GlobalFullerite, Carbon
DS200812-0531
2008
Jung, M.Jung, M., Morel, J., Siffert, P.Numerical simulations for diamond sensors as real time X-ray dosemeters; comparison to silicon.Nuclear Instruments and Methods in Physics Research Section A., No. 587, 1, pp. 125-129.TechnologyX-ray diamond sensors
DS1995-0900
1995
Jung, S.Jung, S.Geochemistry and petrogenesis of rift related Tertiary alkaline rocks From the Rhon area, central Germany.Neues Jahb. fuer Mineralogie, Abhandlungen, Vol. 169, No. 3, pp. 193-226.GermanyAlkaline rocks, Geochemistry
DS2002-0793
2002
Jung, S.Jung, S., Hoernes, S., Mezger, K.Synorogenic melting of mafic lower crust: constraints from geochronology, petrology and Sr Nd, Pb and O isotope geochemistry of quartz diorites, Damara OrogenContributions to Mineralogy and Petrology, Vol.NamibiaGeochronology - not specific to diamonds
DS2002-0794
2002
Jung, S.Jung, S., Hoernes, S., Mezger, K.Synorogenic melting of mafic lower crust: constraints from geochronology, petrology and Sr Nd Pb O isotope geochemistry of diorites from Damara Origin.Contributions to Mineralogy and Petrology, Vol. 143, 5, pp.551-66.NamibiaGeochronology - not specific to diamonds
DS2003-0674
2003
Jung, S.Jung, S., Mezger, K.U Pb garnet chronometry in high grade rocks - case studies from the central DamaraContributions to Mineralogy and Petrology, Vol. 146, 3, Dec. pp. 382-96.NamibiaGeochronology - not specific to diamonds
DS2003-0675
2003
Jung, S.Jung, S., Mezger, K., Hoernes, S.Petrology of basement dominated terranesChemical Geology, Vol. 199, No. 1-2, pp. 1-28.GlobalBlank
DS200412-0937
2004
Jung, S.Jung, S., Merger, K., Hoernes, S.Shear zone related syenites in the Damara belt ( Namibia): the role of crustal contamination and source composition.Contributions to Mineralogy and Petrology, Vol. 148, 1, pp. 104-121.Africa, NamibiaGeneral geology - not specific to diamonds
DS200412-0938
2003
Jung, S.Jung, S., Mezger, K.U Pb garnet chronometry in high grade rocks - case studies from the central Damara orogen ( Namibia) and implications for the SmContributions to Mineralogy and Petrology, Vol. 146, 3, Dec. pp. 382-96.Africa, NamibiaGeochronology - not specific to diamonds
DS200412-0939
2003
Jung, S.Jung, S., Mezger, K., Hoernes, S.Petrology of basement dominated terranes.Chemical Geology, Vol. 199, no. 1-2, pp. 1-28.TechnologyTectonics
DS200612-0650
2006
Jung, S.Jung, S., Hellebrand, E.Trace element fractionation during high grade metamorphism and crustal melting - constraints from ion microprobe dat a of metapelitic, migmatitic and igneous garnets and implications for Sn Nd garnet chronologyLithos, Vol. 87, 1-4, April pp. 193-213.AfricaDamara Orogeny, geochronology Sm-Nd garnet chronology
DS201412-0563
2014
Jung, S.Mayer, B., Jung, S., Romer, R.,Pfander, J., Klugel, A., Pack, A., Groner, E.Amphibole in alkaline basalts from intraplate settings: implications for the petrogenesis of alkaline lavas from the metasomatised lithospheric mantle.Contributions to Mineralogy and Petrology, Vol. 167, 3, pp. 1-22.MantleMetasomatism
DS201808-1777
2018
Jung, S.Pflander, J.A., Jung, S., Klugel, A., Munker, C., Romer, R.L., Sperner, B., Rohrmuller, J.Recurrent local melting of metasomatised lithospheric mantle in response to continental rifting: constraints from basanites and nephelinites/melilitites from SE Germany.Journal of Petrology, Vol. 59, 4, pp. 667-694.Europe, Germanymelilitites

Abstract: Cenozoic primitive basanites, nephelinites and melilitites from the Heldburg region, SE Germany, are high-MgO magmas (8•5-14•1?wt % MgO), with low SiO2 (34•2-47•1?wt %) and low to moderately high Al2O3 (9•0-15•5?wt %) and CaO (8•7-12•7?wt %). The Ni and Cr contents of most samples are up to 470?ppm and 640?ppm, respectively, and match those inferred for primary melts. In multi-element diagrams, all samples are highly enriched in incompatible trace elements with chondrite-normalised La/Yb?=?19-45, strongly depleted in Rb and K, with primitive mantle normalised K/La?=?0•15-0•72, and moderately depleted in Pb. The initial Sr-Nd-Hf isotope compositions (87Sr/86Sr?=?0•7033-0•7051, 143Nd/144Nd?=?0•51279-0•51288 and 176Hf/177Hf?=?0•28284-0•28294) fall within the range observed for other Tertiary volcanic rocks of the Central European Volcanic Province, whereas 208Pb/204Pb and 206Pb/204Pb (38•42-38•88 and 18•49-18•98) are distinctly lower at comparable 207Pb/204Pb (15•60-15•65). Trace element modelling and pressure-temperature estimates based on major element compositions and experimental data suggest that the nephelinites/melilitites formed within the lowermost lithospheric mantle, close to the lithosphere-asthenosphere boundary, by ?3-5% partial melting of a highly enriched, metasomatised, carbonated phlogopite-bearing garnet-lherzolite at temperatures?<1250?°C and pressures of ?2•8?GPa. This corresponds to a melting depth of less than ?85?km. Formation and eruption of these magmas, based on 40Ar/39Ar dating, started in the late Eocene (38•0 Ma) and lasted until the late Oligocene (25•4 Ma). Basanite eruptions occurred in the same area in the middle Miocene, about 7•7 Myr after nephelinite/melilitite generation has ceased, and lasted from 17•7 to 13•1 Ma. The basanites were generated at lower pressures (2•2-1•7?GPa) at similar temperatures (?1220-1250?°C) within the spinel stability field in the lithospheric mantle by 2-6% partial melting. Isotope and trace element systematics indicate that the lithospheric mantle source of the Heldburg magmas was affected by metasomatism associated with long-lasting subduction of oceanic and continental crust during the Variscan orogeny. Aqueous or supercritical fluids that formed at temperatures?<1000?°C and pressures of likely?>4?GPa infiltrated the thermal boundary layer at the base of the lithospheric mantle and imprinted a crustal lead isotope, and to a minor extent crustal Sr, Nd and Hf isotope signatures. They also reduced Nb/U, Ce/Pb, Lu/Hf, Sm/Nd, U/Pb and Th/Pb, but increased Rb/Sr and Nb/Ta and amplified the enrichment of LILE and LREE relative to HREE. This lead to the highly-enriched trace element patterns observed in both sample suites, and to overall less radiogenic 206Pb/204Pb and 208Pb/204Pb compared to other continental basalts in Central Europe, and to less radiogenic 176Hf/177Hf and 143Nd/144Nd that plot distinctly below the terrestrial mantle array. Temporal evolution of magmatism in the Heldburg region coincides with the changing Tertiary intraplate stress field in Central Europe, which developed in response to the Alpine orogeny. Magmatism was most probably caused in response to lithosphere deformation and perturbation of the thermal boundary layer, and not by actively upwelling asthenosphere.
DS202004-0521
2020
Jung, S.Jung, S., Hauff, F., Berndt, J.Generation of a potassic to ultrapotassic alkaline complex in a syn-collisional setting through flat subduction: constraints on magma sources and processes ( Otjimingwe alkaline complex, Damara orogen, Namibia).Gondwana Research, Vol. 82, pp. 267-287.Africa, Namibiametasomatism

Abstract: The ~545 Ma-old syn-collisional Otjimbingwe alkaline complex is composed of pyroxene-amphibole-biotite-bearing, mildly nepheline-normative to quartz-normative rocks ranging in composition from monzogabbro to monzonite, syenite and granite. The alkaline rocks have moderate to high SiO2 (50.5-73.0 wt%) and Na2O + K2O (5.1-11.5 wt%) and moderate to low MgO (6.6-0.2 wt%) concentrations. All samples have high large ion lithophile element (LILE: Ba up to 4600 ppm) and high-field-strength element contents (HFSE; Zr: 155-1328 ppm; Nb: 16-110 ppm; Ta: 1.4-7.1 ppm and Hf: 4-24 ppm) and have strongly fractionated LREE patterns ((La/Yb)N = 14-51). The most primitive members lack significant negative Eu anomalies. Mantle-normalized multi-element diagrams show depletion in Ba, Rb, Nb (Ta), P and Ti. The alkaline rocks have moderate radiogenic initial 87Sr/86Sr ratios (0.7061-0.7087) and unradiogenic initial ?Nd values (?3.9 to ?6.1). This isotope signature, associated with high LREE/HFSE ratios indicates that the parental melts were generated in enriched portions of the shallow lithospheric mantle, which was probably affected by previous subduction zone processes. In addition, correlations between Sr and Nd isotopes indicate that some of these variations result from combined crustal assimilation and fractional crystallization (AFC) processes. A new model of flat subduction is presented that explains most of the unsolved problems in the orogenic evolution of the Damara orogen, namely (i) the absence of early intrusive rocks with a clear subduction zone setting, (ii) the absence of high-pressure rocks such as blueschists and eclogites, (iii) the unusual distribution of igneous rocks with a clear predominance of granite and granodiorite and (iv) the need for a asthenospheric window during a classical subduction to explain the high T/moderate P granulite facies conditions in the overriding plate.
DS202007-1153
2020
Jung, S.Jung, S., Hauff, F., Berndt, J.Generation of a potassic to ultrapotassic alkaline complex in a syn-collisional setting through flat subduction: constraints on magma sources and processes ( Otjimingwe alkaline complex, Damara orogen, Namibia.Gondwana Research, Vol. 82, pp. 267-287. pdfAfrica, Namibiadeposit - Otjimbingwe

Abstract: The ~545 Ma-old syn-collisional Otjimbingwe alkaline complex is composed of pyroxene-amphibole-biotite-bearing, mildly nepheline-normative to quartz-normative rocks ranging in composition from monzogabbro to monzonite, syenite and granite. The alkaline rocks have moderate to high SiO2 (50.5-73.0 wt%) and Na2O + K2O (5.1-11.5 wt%) and moderate to low MgO (6.6-0.2 wt%) concentrations. All samples have high large ion lithophile element (LILE: Ba up to 4600 ppm) and high-field-strength element contents (HFSE; Zr: 155-1328 ppm; Nb: 16-110 ppm; Ta: 1.4-7.1 ppm and Hf: 4-24 ppm) and have strongly fractionated LREE patterns ((La/Yb)N = 14-51). The most primitive members lack significant negative Eu anomalies. Mantle-normalized multi-element diagrams show depletion in Ba, Rb, Nb (Ta), P and Ti. The alkaline rocks have moderate radiogenic initial 87Sr/86Sr ratios (0.7061-0.7087) and unradiogenic initial ?Nd values (?3.9 to ?6.1). This isotope signature, associated with high LREE/HFSE ratios indicates that the parental melts were generated in enriched portions of the shallow lithospheric mantle, which was probably affected by previous subduction zone processes. In addition, correlations between Sr and Nd isotopes indicate that some of these variations result from combined crustal assimilation and fractional crystallization (AFC) processes. A new model of flat subduction is presented that explains most of the unsolved problems in the orogenic evolution of the Damara orogen, namely (i) the absence of early intrusive rocks with a clear subduction zone setting, (ii) the absence of high-pressure rocks such as blueschists and eclogites, (iii) the unusual distribution of igneous rocks with a clear predominance of granite and granodiorite and (iv) the need for a asthenospheric window during a classical subduction to explain the high T/moderate P granulite facies conditions in the overriding plate. Graphical abstract
DS1994-0857
1994
Jung, S.J.Jung, S.J., Smith, M.L.Optimum design of mining structuresAmerican Institute of Mining, Metallurgical, and Petroleum Engineers (AIME) Preprint, Meeting held Albuquerque Feb. 14-17th, No. 94-164, 5pGlobalMining, Computer modeling
DS1998-1551
1998
Jung, W.Vogt, P.R., Jung, W., Brozena, J.Arctic margin gravity highs remain puzzlingEos, Vol. 79, No. 49, Dec. 8, pp. 601, 605, 6.Northwest Territories, ArcticGeophysics - gravity, Oceanic crust
DS1950-0073
1951
Junger, A.Junger, A.Deep Basement Reflections in Big Horn County, MontanaGeophysics, Vol. 16, PP. 499-505.MontanaGeophysics, Mid-continent
DS1990-0786
1990
Jungfeng LuoJungfeng LuoStatistical mineral prediction without defining a training areaMathematical Geology, Vol. 22, No. 3, April pp. 253-260GlobalGeostatistics, Mineral prediction
DS1990-1217
1990
Jungnert, H.Rasanen, M.E., Salo, S., Jungnert, H., Pittman, L.R.Evolution of the Western Amazon Lowland relief: impact of Andean forelanddynamicsTerra Nova, Vol. 2, pp. 320-332Brazil, AndesTectonics, Geomorphology
DS1988-0479
1988
Jun-IchiMiyamoto, M., Matsuda, Jun-Ichi, Ito, K.Raman spectroscopy of diamond in ureilite And implications for the origin of diamondGeophysical Research Letters, Vol. 15, No. 12, pp. 1445-1448GlobalCrystallography, Meteorites
DS1992-0809
1992
Jun-ichi Susaki, et al.Jun-ichi Susaki, et al.Thermal conductivity of rocks at upper mantle conditionProceedings of the 29th International Geological Congress. Held Japan August 1992, Vol. 1, abstract p. 58MantleThermometry, Pyroxenite
DS200912-0034
2009
Junior, F.C.Barros, M.A., Junior, F.C., Nardi, L.V., Lima, E.F.Paleoproterozoic bimodal post collisional magmatism in the southwestern Amazonian Craton, mato Grosso, Brazil: geochemistry and isotopic evidence.Journal of South American Earth Sciences, Vol. 27, no. 1, pp. 11-23.South America, Brazil, Mato GrossoMagmatism
DS2003-0676
2003
Juniper, J.Juniper, J.Mineral claims mapping in the digital age - toward an improved base with high31st Yellowknife Geoscience Forum, p. 48. (abst.NunavutLand permits, leases
DS200412-0940
2003
Juniper, J.Juniper, J.Mineral claims mapping in the digital age - toward an improved base with high resolution imagery and a SDE powered Geodatabase.31st Yellowknife Geoscience Forum, p. 48. (abst.Canada, NunavutLand permits, leases
DS1900-0565
1907
Junius, S.H.Junius, S.H.Iets over Diamanten-kimberleyAlb. Natuur., PP. 363-373.Africa, South AfricaMining Engineering, Kimberley Mining, Diamonds
DS200712-0513
2007
Junji, Y.Kawakami, Y., Junji, Y., Kagi, H.Micro-raman densimeter for CO2 inclusions in mantle derived minerals.Applied Spectroscopy, Vol. 57, 11, pp. 320A-340A-previous Nov 2003 pp.1333-9.TechnologySpectroscopy - xenolith
DS1992-0303
1992
Junk, M.J.Cosca, M.A., Essene, E.J., Junk, M.J., Sutter, J.F.Differential unroofing within the Central Metasedimentary Belt of the Grenville Orogen: constraints from 40Ar/39Ar thermochronologyMineralogy and Petrology, Vol. 110, No. 2/3, pp. 211-225OntarioGeochronology, Central Metasedimentary Belt
DS1930-0194
1935
Junner, N.R.Junner, N.R.Gisements Alluvionnaires de Diamant de la Gold CoastInternational CONGRESS Mines 7TH., Vol. 1, PP. 179-185.GlobalAlluvial Diamond Placers, Bonsa
DS1930-0220
1936
Junner, N.R.Junner, N.R.The Bonsa Diamond Field, Gold Coast ColonyImp. Institute Bulletin., Vol. 34, No. 5, PP. 103-104; PP. 373-374.GlobalDiamonds
DS1940-0071
1943
Junner, N.R.Junner, N.R.The Diamond Deposits of the Gold Coast with Notes on Some Other Diamond Deposits in West Africa.Geological Survey COAST Bulletin., No. 12, 52P.GlobalAlluvial Diamond Placers
DS1940-0117
1946
Junner, N.R.Junner, N.R.Progress on Geological and Mineral Investigations in the Gold Coast.Gold Coast Geological Survey Bulletin., No. 16GlobalGeology, Diamonds
DS1940-0118
1946
Junner, N.R.Junner, N.R.Preliminary Report on the Sierra Leone Diamond FieldsInternal Report Sierra Leone Selection Trust., UNPUB.Sierra Leone, West AfricaGeology
DS2001-0134
2001
JunqueiraBrod, J., Gaspar, De Araujo, Gibson, Thompson, JunqueiraPhlogopite and tetra ferriphlogopite from Brazilian carbonatite complexes and implications for systematicsJournal of African Earth Sciences, Vol. 19, No. 3, Apr. pp.265-296.BrazilCarbonatite, Mineral chemistry systematics
DS2000-0109
2000
Junqueira-BrodBrod, J.A., Gibson, S.A., Thompson, R., Junqueira-BrodMineral chemistry fingerprints of liquid immiscibility and fractionation in the Tapira alkaline - carbonatiteIgc 30th. Brasil, Aug. abstract only 1p.Brazil, Minas GeraisCarbonatite - Alto Paranaiba Igneous Province
DS2000-0110
2000
Junqueira-BrodBrod, J.A., Gibson, S.A., Thompson, R., Junqueira-BrodKamafugite affinity of the Tapira alkaline carbonatite complex (Minas Gerais, Brasil).Igc 30th. Brasil, Aug. abstract only 1p.Brazil, Minas GeraisCarbonatite - Araxa, Serra Negra, Salitre, Catalao, Kamafugites
DS200712-0144
2007
Junqueira-BrodCarlson, R.W., Aruajo, Junqueira-Brod, Gaspar, Brod, Petrinovic, Hollanda, Pimentel, SichelChemical and isotopic relationships between peridotite xenoliths and mafic-ultrapotassic rocks from southern Brazil.Chemical Geology, Vol. 242, 3-4, pp. 418-437.South America, BrazilGeochemistry
DS200712-0145
2007
Junqueira-BrodCarlson, R.W., Aruajo, Junqueira-Brod, Gaspar, Brod, Petrinovic, Hollanda, Pimentel, SichelChemical and isotopic relationships between peridotite xenoliths and mafic-ultrapotassic rocks from southern Brazil.Chemical Geology, Vol. 242, 3-4, pp. 418-437.South America, BrazilGeochemistry
DS2003-0167
2003
Junqueira-Brod, T.C.Brod, J.A., Gaspar, J.C., Diniz-Pinto, H.S., Junqueira-Brod, T.C.Spinel chemistry as an indicator of crystal fractionation and liquid immiscibility in the8 Ikc Www.venuewest.com/8ikc/program.htm, Session 7, POSTER abstractBrazil, Minas GeraisBlank
DS2003-0168
2003
Junqueira-Brod, T.C.Brod, J.A., Junqueira-Brod, T.C., Gaspar, J.C., Gibson, S.A., Thompson, R.N.Ti rich and Ti poor garnet from the Tapira carbonatite complex, SE Brazil: fingerprinting8 Ikc Www.venuewest.com/8ikc/program.htm, Session 7, POSTER abstractBrazil, Minas GeraisBlank
DS2003-0677
2003
Junqueira-Brod, T.C.Junqueira-Brod, T.C., Brod, J.A., Gaspar, J.C., Barbosa, E.S.R.Magma - sediments interaction in the Aguas Emendadas kamafugitic diatremes, GO8ikc, Www.venuewest.com/8ikc/program.htm, Session 1 POSTER abstractBrazil, GoiasKimberlite geology and economics, Deposit - Aguas Emendadas
DS2003-0678
2003
Junqueira-Brod, T.C.Junqueira-Brod, T.C., Gaspar, J.C., Brod, J.A., Barbosa, E.S.R.Magma mixing in Cretaceous kamafugites, Goias alkaline province, Brazil8ikc, Www.venuewest.com/8ikc/program.htm, Session 1 POSTER abstractBrazil, GoiasKimberlite geology and economics
DS200412-0213
2003
Junqueira-Brod, T.C.Brod, J.A., Gaspar, J.C., Diniz-Pinto, H.S., Junqueira-Brod, T.C.Spinel chemistry as an indicator of crystal fractionation and liquid immiscibility in the Tapira alkaline carbonatie complex, Mi8 IKC Program, Session 7, POSTER abstractSouth America, Brazil, Minas GeraisKimberlite petrogenesis
DS200412-0214
2003
Junqueira-Brod, T.C.Brod, J.A., Junqueira-Brod, T.C., Gaspar, J.C., Gibson, S.A., Thompson, R.N.Ti rich and Ti poor garnet from the Tapira carbonatite complex, SE Brazil: fingerprinting fractional crystallization and liquid8 IKC Program, Session 7, POSTER abstractSouth America, Brazil, Minas GeraisKimberlite petrogenesis
DS200512-0492
2005
Junqueira-Brod, T.C.Junqueira-Brod, T.C., Gaspar, J-C., Brod, J.A., Jost, H., Rocha Barbosa, E.S., Kafino, C.V.Emplacement of kamafugitic lavas from the Goais alkaline province, Brazil: constraints from whole rock simulations. (mafurite, ugandite)Journal of South American Earth Sciences, Vol. 18, 3-4, March pp. 323-335.South America, BrazilSanto Antonio da Barra, Aguas Emendadas, carbonatite
DS200512-0493
2005
Junqueira-Brod, T.C.Junqueira-Brod, T.C., Gaspar, J-C., Brod, J.A., Kafino, C.V.Kamafugitic diatremes: their textures and field relationships with examples from the Goais alkaline province, Brazil.Journal of South American Earth Sciences, Vol. 18, 3-4, March pp. 337-353.South America, BrazilBreccia, lapilli, peperite, surge
DS200512-0902
2005
Junqueira-Brod, T.C.Ribeiro, C.C., Brod, J.A., Junqueira-Brod, T.C., Gaspar, J-C., Petrinovic, I.A.Mineralogical and field aspects of magma fragmentation deposits in a carbonate phosphate magma chamber: evidence from the Catalao I complex, Brazil.Journal of South American Earth Sciences, Vol. 18, 3-4, March pp. 355-369.South America, BrazilCarbonatite, Lagoa Seca, APIP, chamber pipes, surge
DS200812-0077
2008
Junqueira-Brod, T.C.Barbosa, E.S.R., Junqueira-Brod, T.C., Brod, J.A., Dantas, E.L.Petrology of bebdourites from the Salitre phoscorite carbonatite complex, Brazil.9IKC.com, 3p. extended abstractSouth America, BrazilCarbonatite
DS201212-0053
2012
Junqueira-Brod, T.C.Barbosa, E.S.R., Brod, J.A., Junqueira-Brod, T.C., Cordeiro, P.F.O., Santos, R.V., Dantas, E.L.Phoscorites from the Salitre alkaline complex, Brazil: origin and petrogenetic implications.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractSouth America, BrazilDeposit - Salitre
DS201212-0054
2012
Junqueira-Brod, T.C.Barbosa, E.S.R., Brod, J.A., Junqueira-Brod, T.C., Cordeiro, P.F.O.,Dantas, E.L., Santos, R.V.Mineralogy and petrology of the Salitre 1 phoscorite carbonatite alkaline compelx, Brazil.10th. International Kimberlite Conference Held Bangalore India Feb. 6-11, Poster abstractSouth America, BrazilDeposit - Slitre 1
DS201212-0681
2012
Junqueira-Brod, T.C.Soares Rocha Barbosa, E., Brod, J.A., Junqueira-Brod, T.C., Dantas, E.L., De Oliveira Cordeiro, P.F., Siqueira Gomide, C.Bebdourite from its type area Sailtre 1 complex: a key petrogenetic series in the Late-Cretaceous Alto Paranaiba kamafugite carbonatite phoscorite association, central Brazil.Lithos, Vol. 146-147, pp. 56-72.South America, BrazilCarbonatite
DS201312-0100
2013
Junqueira-Brod, T.C.Brod, J.A., Junqueira-Brod, T.C., Gaspar, J.C., Petrinovic, I.A., De Castro Valente, S., Corval, A.Decoupling of paired elements, crossover REE patterns and mirrored spider diagrams: fingerprinting liquid immiscibility in the Tapira alkaline carbonatite complex, SE Brazil.Journal of South American Earth Sciences, Vol. 41, pp. 41-56.South America, BrazilTapira - mineral chemistry
DS201312-0319
2013
Junqueira-Brod, T.C.Gomide, C.S., Brod, J.A., Junqueira-Brod, T.C., Buhn, B.M., Santos, R.V., Barbosa, E.S.R., Cordeiro, P.F.O., Palmieri, M., Grasso, C.B., Torres, M.G.Sufur isotopes from Brazilian alkaline carbonatite complexes.Chemical Geology, Vol. 341, pp. 38-49.South America, BrazilDeposit - Tapira, Salitre, Serra Negra, Catalao, Jacupiringa
DS200812-0840
2008
Junquiera-Brod, T.C.Palmieri, M., Pereira, G.S.B., Brod, J.A., Junquiera-Brod, T.C., Petrinovic, I.A., Ferrari, A.J.D.Orbicular magnetite from the Catalao I phoscorite carbonatite complex.9IKC.com, 3p. extended abstractSouth America, BrazilCarbonatite
DS1992-0810
1992
Junsuo LiuJunsuo Liu, Barnes, S.., Woussenl, G.The mantle sources of the lamproites, basanites and trachy basalts from the Hunan-Guangxi Provinces, southern ChinaEos Transactions, Vol. 73, No. 14, April 7, supplement abstracts p.337ChinaLamproites, Basanite
DS201712-2705
2017
Junter, J.McPeak, S., Mallozzi, S., Samson, C., Elliott, B., Junter, J.Estimating overburden depth in a permafrost rich environment using passive seismics: results from the 2017 preliminary survey at Kennady Camp.45th. Annual Yellowknife Geoscience Forum, p. 103 abstract posterCanada, Northwest Territoriesdeposit - Kennady
DS1995-1167
1995
Juntz, R.D.Mareschal, M., Kellett, R.L., Juntz, R.D., Ludden, J.N. Li.Archean cratonic roots, mantle shear zones and deep electrical SOURCE[ NatureNature, Vol. 375, No. 6527, May 11, pp. 134-136.MantleCraton, Geophysics
DS1992-1520
1992
Junwen, W.Tatsumoto, M., Basu, A.R., Wankang, H., Junwen, W., Guanghong, X.Strontium, neodymium, lead isotopes of ultramafic xenoliths in volcanicEarth and Planetary Science Letters, Vol. 113, No. 1-2, September pp. 107-128ChinaGeochronology, Xenoliths
DS2002-0946
2002
Juo, B.Y.Lin, S.C., Chiao, L.Y., Juo, B.Y.Dynamic interaction of cold anomalies with the mid-ocean ridge flow field and its implications for the Australian Antarctic discordance.Earth and Planetary Science Letters, Vol. 203, 3-4, pp. 925-35.AustraliaGeodynamics
DS2001-0077
2001
JupilleBalan, E., Trocellier, Jupille, Fritsch, Muller, CalasSurface chemistry of weathered zirconsChemical Geology, Vol. 181,No. 1-4, pp. 13-22.Brazil, Amazon BasinSEM, spectroscopy, weathering - not specific to diamond
DS1989-0736
1989
Jupp, D.L.B.Jupp, D.L.B., Strahler, A.H., Woodcock, C.E.Auto correlation and regularization in digital images II. Simple imagemodelsGeoscience and Remote Sensing, Vol. 27, No. 3, May pp. 247-258GlobalRemote Sensing, Autocorrelation
DS1989-0737
1989
Jupp, P.E.Jupp, P.E., Spurr, B.D.Statistical estimation of a shock center: Slate Islands astroblemeMathematical Geology, Vol. 21, No. 2, pp. 191-198Ontario, United StatesGeostatistics
DS1990-0787
1990
Jurdy, D.M.Jurdy, D.M., Stefanik, M.Models for the hotspot distributionGeophysical Research Letters, Vol. 17, No. 11, October pp. 1965-1968GlobalHotspots, Subduction zones
DS1991-0814
1991
Jurdy, D.M.Jurdy, D.M., Stefanik, M.The forces driving the plates: constraints from kinematics and stressobservationsPhil. Transactions Royal Society of London, Vol. 337, No. 1645, October 15, pp. 127-140GlobalMantle, Plate tectonics
DS1992-0811
1992
Jurdy, D.M.Jurdy, D.M., Stefanik, M.The forces driving the plates: constraints from kinematics and hotspotsEos Transactions, Vol. 73, No. 14, April 7, supplement abstracts p. 272MantleHotspots, Tectonics
DS1995-0901
1995
Jurdy, D.M.Jurdy, D.M., Stefanik, M., Scotese, C.R.Paleozoic plate tectonicsJournal of Geophysical Research, Vol. 100, No. 9, Sept. 10, pp. 7965-76GlobalTectonics -Plate, Paleozoic
DS2000-0459
2000
Jurdy, D.M.Jurdy, D.M.Superplume events and polar wanderGeological Society of America (GSA) Abstracts, Vol. 32, No. 7, p.A-314.MantlePolar wandering, Paleomagnetism
DS200612-0296
2006
Jurdy, D.M.Cuffaro, M., Jurdy, D.M.Microplate motions in the hotspot reference frame.Terra Nova, Vol. 18, 4, pp. 276-281.MantleHotspots
DS200712-0323
2007
Jurdy, D.M.Foulger, G.R., Jurdy, D.M.Plates, plumes and planetary processes.GSA Bookstore, 950p. approx. $ 180.00MantleBook - individual papers of interest cited separately
DS1990-0788
1990
Jurgens, H.Jurgens, H., Pietgen, H-O., Saupe, D.The language of fractalsScientific American, Vol. 263, No. 2, August pp. 60-67GlobalFractals, Layman's overview
DS1989-1017
1989
Jurick, D.Micrus, K.L., Keller, G.R., Jurick, D., Gurrola, H.Crustal structure of the southern margin of North america determined from gravity modelingGeological Society of America (GSA) Annual Meeting Abstracts, Vol. 21, No. 6, p. A99. AbstractMidcontinentGeophysics -gravity, Tectonics
DS1990-1038
1990
Jurick, D.Mickus, K., Keller, G.R., Hamilton, L., Jurick, D., Gurrola, H.Geophysical transects across the southern midcontinent region of the UnitedStatesGeological Society of America (GSA) Annual Meeting, Abstracts, Vol. 22, No. 7, p. A191GlobalGeochronology, Geophysics
DS200512-0494
2005
Jurine, D.Jurine, D., Jaupart, C., Brandeis, G., Tackley, P.J.Penetration of mantle plumes through depleted lithosphere.Journal of Geophysical Research, Vol. 110, B10, B 10104 10.1029/2005 JB003751MantleTectonics
DS1900-0768
1909
Juritz, C.F.Juritz, C.F.Topographical and Geological Terms in Local Use in South Africa.British Association Advanced Science Reports, PP. 481-482.Africa, South AfricaHistory, Toponomy
DS1988-0522
1988
Jurkowski, I.Ollier, C.D., Gaunt, G.F.M., Jurkowski, I.The Kimberley Plateau, Western Australia: a Precambrian erosionSOURCE[ Zeitschrift fur GeomorphologieZeitschrift fur Geomorphologie, Vol. 32, No. 2, June pp. 239-246AustraliaTectonics, Kimberley Plateau
DS1995-2129
1995
Jurtz, R.Zhang, P., Chouteau, M., Mareschal, M., Jurtz, R., HubertHigh frequency magnetotelluric investigation of crustal structure in north central Abitibi QuebecGeophy. Journal, Vol. 120, pp. 406-418QuebecLithoprobe - AMT, Abitibi greenstone belt
DS1990-0789
1990
Just, J.Just, J.Cathodluminesence of diamondsGems and Gemology, 15th, General Meeting International Mineralogical Association held, Vol. 26, Winter p. 314. AsbtractGlobalCathodluminesence, Diamond identification
DS1990-0790
1990
Just, J.Just, J.Cathodluminescence of diamondsInternational Mineralogical Association Meeting Held June, 1990 Beijing China, Vol. 1, extended abstract p. 182-184GlobalDiamond morphology, Cathodluminescence
DS201506-0278
2015
Justo, J.F.Justo, J.F., Morra, G., Yuen, D.A.Viscosity undulations in the lower mantle: the dynamical role of iron spin transition.Earth and Planetary Science Letters, Vol. 421, pp. 20-26.MantleCore
DS201901-0072
2018
Justo, J.F.Santos, S.S.M., Marcondes, M.L., Justo, J.F., Assali, L.V.C.Stability of calcium and magnesium carbonates at Earth's lower mantle thermodynamic conditions.Earth and Planetary Science Letters, Vol. 506, pp. 1-7.Mantlegeodynamics

Abstract: We present a theoretical investigation, based on ab initio calculations and the quasi-harmonic approximation, on the stability properties of magnesium (MgCO3) and calcium (CaCO3) carbonates at high temperatures and pressures. The results indicate that those carbonates should be stable in the Earth's lower mantle, instead of dissociating into other minerals, in chemical environments with excess of SiO2, MgO, or MgSiO3. Therefore, considering the lower mantle chemical composition, consisting mostly of the MgSiO3 and MgO minerals, calcium and magnesium carbonates are the primary candidates as carbon hosts in that region. For the thermodynamic conditions of the mantle, the results also indicate that carbon should be primarily hosted on MgCO3, contrasting with what was found by other theoretical studies, which neglected temperature effects. Finally, the results indicate that carbon, in the form of free CO2, is unlikely in the lower mantle.
DS1999-0345
1999
Juteau, T.Juteau, T., Maury, R.The Oceanic crust, from accretion to mantle recyclingSpringer, 385p. approx. $ 150.00 United StatesOceanic, crustGeophysics, geodesy, Oceanic lithosphere
DS1860-0368
1881
JutierJutierExploitation du Diamant dans la Colonie du CapSoc. Ind. Min. (st. Etienne) C.r., PP. 34-37.Africa, South AfricaGeology
DS200612-0850
2005
Juvonen, R.Maier, W.D., Peltonen, P., Juvonen, R., Pienaar, C.Platinum group elements in peridotite xenoliths and kimberlite from the Premier kimberlite pipe, South Africa.South African Journal of Geology, Vol. 108, pp. 413-428.Africa, South AfricaDeposit - Premier, xenolith mineralogy
DS1994-1979
1994
Jux, U.Zeese, R., Scwertmann, U., Tietz, G.F., Jux, U.Mineralogy and stratigraphy of three deep lateritic profiles of the Josplateau (Central Nigeria)Catena, Laterization and Supergene Ore, Vol. 21, No. 2-3, pp. 195-214NigeriaMIneralogy, Laterization
DS2001-0556
2001
JVXJVXComputed conductivity time sections of PROTEM -47 ( TDEM) dat a measured over known kimberlites Lac de GrasJvx Promotional Info, 3p. text, 2 graphsNorthwest TerritoriesGeophysics - TDEM.
Author Index
A-An Ao+ B-Bd Be-Bk Bl-Bq Br+ C-Cg Ch-Ck Cl+ D-Dd De-Dn Do+ E F-Fn Fo+ G-Gh Gi-Gq Gr+ H-Hd He-Hn Ho+ I J K-Kg Kh-Kn Ko-Kq Kr+ L-Lh
Li+ M-Maq Mar-Mc Md-Mn Mo+ N O P-Pd Pe-Pn Po+ Q R-Rh Ri-Rn Ro+ S-Sd Se-Sh Si-Sm Sn-Ss St+ T-Th Ti+ U V W-Wg Wh+ X Y Z
 
 

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