2015 Reference Compilation |
Posted/ Published | Author | Title | Source | Region | Keywords |
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DC201512-2413 2015 | 92 Resources Corporation | 92 Resources Corp. considers FIn land diamond property, announces working capital private placement. | 92 Resources Corporation, Nov. 18, 1p. | Europe, Finland | News item - press release |
DM201511-2110 2015 | Abreu, F., Silva, L.F. | How illegal diamond mining threatens Brazil's indigenous communities. Reported in Republicofmining.com | insightcrime.org, Oct. 14, 2p. | South America, Brazil | News item - legal |
DC201507-1379 2015 | Adamera Minerals Corporation | Adamera completes sale of diamond data. | Adamera Minerals Corp., May 28, 1p. | Canada, Nunavut | News item - press release |
DS201502-0036 2015 | Afanasiev, V., Ashchekov, I., Nikolenko, E. | Concentrates and mantle xenocrysts from the Lao River Guinea and reconstruction of the mantle structure. | Economic Geology Research Institute 2015, Vol. 17,, # 2484, 1p. Abstract | Africa, Guinea | Kimberlite dykes |
DC201502-1380 2015 | Afri-Can Marine Minerals Corporation | Afri-Can Marine Minerals Corporation trading halt and resignation of executives and directors. | Afri-Can Marine Minerals Corporation, Jan. 5, 1p. | Africa, Namibia | News item - press release |
DS201501-0001 2014 | Ague, J.J. | Deep carbon: subduction goes organic. | Nature Geoscience, 2p. | Mantle | Carbon |
| Abstract: Aqueous subduction-zone fluids contain CO2 and methane. New calculations indicate that these fluids also host a wide array of organic carbon species, in concentrations sufficient to influence the deep carbon cycle. |
DS201511-1819 2014 | Ahmat, A.L. | The Ellendale diamond field: exploration history, discovery, geology and mining. | Australian Gemmologist, Vol. 24, 12, pp. 280-288. | Australia | Deposit - Ellendale |
| Abstract: The Ellendale diamond field in West Kimberley is one of only three hard-rock diamond mine locations in Australia. Though not the first Australian diamond mine, Ellendale was the country’s first hard-rock deposit. It holds a special place in world diamond history as it led in November 1976 to the recognition of a new host-rock for diamond, olivine lamproite. Up until that time, commercial-sized diamonds were considered to be sourced only from kimberlite. The Ellendale lamproites are geologically very young, only 22 Ma (million of years) old. Within several years of the initial discovery, some 46 lamproite pipes were found at Ellendale. By 1980, 38 of these pipes had been assessed for their diamond content. More than two decades later, geologists from the Kimberley Diamond Company (KDC) recognized eluvial diamond enrichment over these pipes. After a lengthy legal battle, they wrested the Ellendale mining lease from the Ashton Joint Venture and commenced mining there in May 2002. Ellendale is recognized as a source of high-value fancy yellow diamonds. These high priced stones have been marketed through a special deal with Tiffany & Co since 2009. But the future of mining there is tenuous. Ellendale 4 was closed in 2009, and the high Australian dollar, combined with dwindling reserves, may jeopardize the survival of Ellendale 9. |
DS201502-0037 2015 | Ahmed, A.H., Habtoor, A. | Heterogeneously depleted Precambrian lithosphere deduced from mantle peridotites and associated chromitite deposits of Al, Ays ophiolite, northwestern Arabian shield, Saudi Arabia. | Ore Geology Reviews, Vol. 67, pp. 279-296. | Africa, Saudi Arabia | Peridotite |
| Abstract: The mantle section of Al'Ays ophiolite consists of heterogeneously depleted harzburgites, dunites and large-sized chromitite pods. Two chromitite-bearing sites (Site1 and Site2), about 10 km apart horizontally from one another, were examined for their upper mantle rocks. Cr-spinels from the two sites have different chemistry; Cr-rich in Site1 and Al-rich in Site2. The average Cr-ratio = (Cr/(Cr + Al) atomic ratio) of Cr-spinels in harzburgites, dunites and chromitites is remarkably high 0.78, 0.77 and 0.87, respectively, in Site1, compared with those of Site2 which have intermediate ratio averages 0.5, 0.56 and 0.6, respectively. The platinum-group elements (PGE) in chromitites also show contrasting patterns from Site1 to Site2; having elevated IPGE (Os, Ir, Ru) and strongly depleted in PPGE (Rh, Pt, Pd) with steep negative slopes in the former, and gentle negative slopes in the latter. The oxygen fugacity (?log fO2) values deduced from harzburgites and dunites of Site1 show a wide variation under reducing conditions, mostly below the FMQ buffer. The Site2 harzburgites and dunites, on the other hand are mostly above the FMQ buffer. Two magmatic stages are suggested for the lithospheric evolution of Al'Ays ophiolite in response to a switch of tectonic setting. The first stage produced a peridotites–chromitites suite with Al-rich Cr-spinels, possibly beneath a mid-ocean ridge setting, or most likely in back-arc rift of a supra-subduction zone setting. The second stage involved higher degrees of partial melting, produced a peridotites–chromitites suite with Cr-rich Cr-spinels, possibly in a fore-arc setting. The coexistence of compositionally different mantle suites with different melting histories in a restricted area of an ophiolite complex may be attributable to a mechanically juxtaposed by mantle convection during recycling. The mantle harzburgites and dunites are apt to be compositionally modified during recycling process; being highly depleted (Site1 case) than their original composition (Site2 case). |
DS201503-0131 2015 | Alifirova, T.A., Pokhilenko, L.N., Korsakov, A.V. | Apatite, SiO2, rutile and orthopyroxene precipitates in minerals of eclogite xenoliths from Yakutian kimberlites, Russia. | Lithos, Vol. 226, pp. 31-49. | Russia, Yakutia | Deposit - Udachnaya, Zarnitsa, Obnazhennaya |
| Abstract: Eclogite mantle xenoliths from the central part of Siberian craton (Udachnaya and Zarnitsa kimberlite pipes) as well as from the northeastern edge of the craton (Obnazhennaya kimberlite) were studied in detail. Garnet and clinopyroxene show evident exsolution textures. Garnet comprises rutile, ilmenite, apatite, and quartz/coesite oriented inclusions. Clinopyroxene contains rutile (± ilmenite) and apatite precipitates. Granular inclusions of quartz in kyanite and garnet usually retain features of their high-pressure origin. According to thermobarometric calculations, studied eclogitic suite was equilibrated within lithospheric mantle at 3.2–4.9 GPa and 813–1080 °C. The precursor composition of garnets from Udachnaya and Zarnitsa eclogites suggests their stability at depths 210–260 km. Apatite precipitation in clinopyroxenes of Udachnaya and Zarnitsa allows us to declare that original pyroxenes could have been indicative of their high P–T stability. Raman spectroscopic study of quartz and coesite precipitates in garnet porphyroblasts confirms our hypothesis on the origin of the exsolution textures during pressure-temperature decrease. With respect to mineralogical data, we suppose the rocks to be subjected to stepwise decompression and cooling within mantle reservoir. |
DM201501-0441 2014 | AllAfrica | Missing 100 carat diamond sold for US $ 1.5 million in Dubai. West African diamond company. | Allafrica.com, Dec. 15, 1p. | Africa, Liberia | News item - legal |
DM201501-2481 2014 | AllAfrica | Botswana: more in store for Jwaneng, Orapa mines. | Allafrica.com, Nov. 30, 1p. | Africa, Botswana | News item - Debswana |
DM201502-0442 2014 | AllAfrica | Mwadui U.S. production, mine life span. | Allafrica.com, Dec. 22, 1/2p. | Africa, Tanzania | News item - Petra |
DM201502-0443 2014 | AllAfrica | Endiama to reduce operation costs. | Allafrica.com, Dec. 30, 1/4p. | Africa, Angola | News item - Endiama |
DM201502-0444 2014 | AllAfrica | Gov't still fighting for diamonds seized in Belgium. | Allafrica.com, Dec. 30, 1/4p. | Africa, Zimbabwe | News item - legal |
DM201502-0445 2015 | AllAfrica | Lunda Sul - Catoca ensures continued focus on betterment of working conditions. | Allafrica.com, Jan. 5, 1/4p. | Africa, Angola | News item - Catoca |
DM201502-0446 2015 | AllAfrica | Its time we became diamond people. ( value added processes needed) | Allafrica.com, Jan. 10, 1p. | Africa, Zimbabwe | News item - legal |
DM201502-0447 2015 | AllAfrica | Fresh bid to grab mining companies…. Murowa mentioned. | Allafrica.com, Jan. 17, 1/4p. | Africa, Zimbabwe | News item - Rio Tinto |
DM201503-0448 2015 | AllAfrica | Angolan mining sector new project … Cambange in eastern Lunda Norte. | Allafrica.com, Feb. 12, 1p. | Africa, Angola | News item - Mining UARi-society |
DM201504-0452 2015 | AllAfrica | Chinamasa - forget diamonds, Zim is broke. | AllAfrica.com, Mar. 5, 1/2p. | Africa, Zimbabwe | News item - Marange |
DM201504-0453 2015 | AllAfrica | Botswana: Debswana upgrades Seepapitso Labs. | AllAfrica.com, Mar. 12, 1/2p. | Africa, Namibia | News item - Debswana |
DM201504-0454 2015 | AllAfrica | Diamond board wants 24 hr access to Oranjemund. | AllAfrica.com, Mar. 12, 1/2p. | Africa, Namibia | News item - legal |
DM201505-0449 2015 | AllAfrica | Production at Mwadui Diamond mine rises. 27% to 57,542 carats | Allafrica.com, Apr. 17, 1/4p. | Africa, Tanzania | News item - Petra |
DM201505-2476 2015 | AllAfrica | Diamond miners on looting spree. | Allafrica.com, Mar. 27, 1/4p. | Africa, Zimbabwe | News item - Marange |
DM201507-0455 2015 | AllAfrica | Govt loses potential revenue after mine's closure. DTZ-OZGEO alluvial operation. | Allafrica.com, June 2, 1/4p. | Africa, Zimbabwe | News item - DTZ-OZGEO |
DM201507-0456 2015 | AllAfrica | Zim sells $ 1.4 million carats of rough diamonds. | Allafrica.com, June 11, 1/4p. | Africa, Zimbabwe | News item - rough |
DM201508-0450 2015 | AllAfrica | Riozim committed to Murowa. Rio Zim held 22 % and now controls the entity after its major shareholder Gem Holdings bought 78 % from Rio Tinto. | Allafrica.com, July 16, 1p. | Africa, Zimbabwe | News item - RioZim |
DM201508-0451 2015 | AllAfrica | Debswana Diamond Company shown commitment to the submission of training and labour. | Allafrica.com, July 27, 1/2p. | Africa, Botswana | News item - CSR |
DM201508-2482 2015 | AllAfrica | Angola, Russia discuss co-operation in diamond industry. Catoca, Tchiuzo, Luaxe | Allafrica.com, July 2, 1/4p. | Africa, Angola | News item - Alrosa |
DM201510-2000 2015 | AllAfrica | Diamond production increases in country. Catoca | Allafrica.com, Aug. 27, 1/4p. | Africa, Angola | News item - production |
DM201510-2001 2015 | AllAfrica | Mwadui mine life extended 20 years. | Allafrica.com, Sept. 19, 1/4p. | Africa, Tanzania | News item - Petra |
DM201512-2210 2015 | AllAfrica | Marange diamond licences have now expired: minister.. Giving government an advantage for consolidation of the sector. | Allafrica.com, Oct. 30, 1p. | Africa, Zimbabwe | News item - Marange |
DM201512-2211 2015 | AllAfrica | Gun thefts leave diamond big shots paranoid. | Allafrica.com, Nov. 27, 1/4p. | Africa, Namibia | News item - legal |
DM201512-2212 2015 | AllAfrica | Namibia has 1,5 billion carats at sea. | Allafrica.com, Nov. 27, 1/4p. | Africa, Namibia | News item - marine mining |
DM201512-2213 2015 | AllAfrica | Debswana partnership solid in Botswana. | Allafrica.com, Nov. 23, 1/4p. | Africa, Botswana | News item - Debswana |
DC201503-1383 2015 | Alrosa | Alrosa reports Q2 production results. H1 2014 results and sales. | Alrosa, Jan. 31, 3p. | Russia | News item - press release |
DC201505-1384 2015 | Alrosa | Alrosa Investors-Day presentation. Detailed locations, projects, financials | Alrosa, Apr. 8, 45ppt | Russia | News item - Alrosa |
DC201505-1385 2015 | Alrosa | Alrosa's executive Committtee considered the 2014 exploration performance to declare all the targets successfully achieved. | [email protected], Apr. 17, 2p. | Russia | News item - press release |
DC201501-1386 2014 | Alto Ventures Ltd. | Alto initiates airborne magnetometer survey on its Pikoo area, diamond claims, Saskatchewan. | Alto Ventures Lt., Dec. 17, 1p. | Canada, Saskatchewan | News item - press release |
DC201502-1387 2015 | Alto Ventures Ltd. | Alto Ventures review of 2014 activities. Pikoo | Alto Ventures Ltd., Jan. 14, 1p. | Canada, Saskatchewan | News item - press release |
DC201502-1388 2015 | Alto Ventures Ltd. | Alto Ventures confirms kimberlite indicator minerals on the GEFA property adjacent to Pikoo, Northern Saskatchewan. | Alto Ventures Ltd., Jan. 22, 2p. | Canada, Saskatchewan | News item - press release |
DC201504-1389 2015 | Alto Ventures Ltd. | Priority targets identified from high resolution airborne magnetic Survey adjacent to Pikoo diamond discovery, northern Saskatchewan. | Alto Ventures Ltd., Feb. 26, 2p. | Canada, Saskatchewan | News item - press release |
DC201505-1390 2015 | Alto Ventures Ltd. | Alto Ventures recovers kimberlite indicator minerals on the West Fisher claims northwest of the Pikoo diamond discovery, northern Saskatchewan. | Alto Ventures Ltd., Apr. 1, 1p. | Canada, Saskatchewan | News item - press release |
DC201505-1391 2015 | Alto Ventures Ltd. | Priority targets from high resolution airborne magnetic survey over West Fisher claims northwest of Pikoo diamond discovery, northern Saskatchewan. | Alto Ventures Ltd., Apr. 22, 1p. | Canada, Saskatchewan | News item - press release |
DC201510-2329 2015 | Alto Ventures Ltd. | Alto Ventures arranges financing plans till sampling on its Pikoo area claims, northern Saskatchewan. | Alto Ventures Limited, Sept. 24, 1p. | Canada, Saskatchewan | News item - press release |
DS201503-0132 2015 | Amit, H., Olson, P. | Lower mantle superplume growth excites geomagnetic reversals. | Earth and Planetary Science Letters, Vol. 414, March 15, pp. 68-76. | Mantle | Hotspots |
| Abstract: Seismic images of the lower mantle reveal two large-scale, low shear wave velocity provinces beneath Africa and the Pacific that are variously interpreted as superplumes, plume clusters or piles of dense mantle material associated with the layer. Here we show that time variations in the height of these structures produce variations in heat flux across the core–mantle boundary that can control the rate at which geomagnetic polarity reversals occur. Superplume growth increases the mean core–mantle boundary heat flux and its lateral heterogeneity, thereby stimulating polarity reversals, whereas superplume collapse decreases the mean core–mantle boundary heat flux and its lateral heterogeneity, inhibiting polarity reversals. Our results suggest that the long, stable polarity geomagnetic superchrons such as occurred in the Cretaceous, Permian, and earlier in the geologic record were initiated and terminated by the collapse and growth of lower mantle superplumes, respectively. |
DM201511-2111 2015 | Amnesty International | Chains of abuse: the case of diamonds from the Central African Republic and the global diamond supply chain. | Amnestyinternational.org, Sept. 3p. | Africa, Central African Republic | News item - KP, CSR |
| Abstract: Amnesty International has examined three specific points in the global diamond supply chain, starting with diamonds in the Central African Republic (CAR), moving to two of CAR’s neighbours into which some of its diamonds are smuggled, and ending at diamond exchanges in the major global trading centres of Antwerp and Dubai. CAR has been embroiled in armed conflict since late 2012. The report uses CAR as a case study to examine the diamond supply chain but looks beyond the conflict to human rights abuses in the artisanal mining sector in CAR and to other illegal and unethical practices in the diamond supply chain that cause or contribute to human rights abuses – such as smuggling and tax abuse. |
DS201501-0002 2014 | Anderson, D.L., King, S.D. | Driving the Earth machine? | Science, Vol. 346, 6214, pp. 1184-1185. | Mantle | Athenosphere, magmatism |
| Abstract: The asthenosphere—derived from the Greek asthen?s, meaning weak—is the uppermost part of Earth's mantle, right below the tectonic plates that make up the solid lithosphere. First proposed by Barrell 100 years ago (1), the asthenosphere has traditionally been viewed as a passive region that decouples the moving tectonic plates from the mantle and provides magmas to the global spreading ridge system. Recent studies suggest that the asthenosphere may play a more active role as the source of the heat and magma responsible for intraplate volcanoes. Furthermore, it may have a major impact on plate tectonics and the pattern of mantle flow. |
DS201510-1756 2014 | Andreeva, I.A. | Salt ( carbonatite) melts of the Bol'shaya Tagna Massif, the eastern Sayan region: evidence from melt inclusions. | Deep-seated magmatism, its sources and plumes, Proceedings of XIII International Workshop held 2014., Vol. 2014, pp. 148-159. | Russia | Mineral chemistry |
DS201502-0038 2015 | Angel, R.J., Alvaro, M., Nestola, F., Mazzucchelli, M.L. | Diamond thermoelastic properties and implications for determining the pressure of formation of diamond inclusion systems. | Russian Geology and Geophysics, Vol. 56, 1-2, pp. 211-220. | Technology | Diamond inclusions |
| Abstract: The formation conditions of diamond can be determined from the residual pressure of inclusions trapped within the diamond, as measured at ambient conditions, and the equations of state (EoS) of the mineral inclusion and the host diamond. The EoS parameters of the diamond and the inclusion phase are therefore critical for determining the precision and accuracy of the calculation of formation conditions of diamonds. The questions we address are (i) How precise are these calculations? and, in particular, (ii) Do we know the EoS parameters of diamond to a precision and accuracy which do not contribute significantly to uncertainties in the geological conclusions drawn from these calculations? We present a review of the most recent compressional data, simulations, and direct elastic measurements of diamond and show them to be consistent with a room-temperature bulk modulus of K0T = 444(2) GPa and a pressure derivative K = 4.0. In combination with a thermal-pressure model with parameters aV300,0 = 2.672(3) x 10- 6 K- 1 and a single Einstein temperature 0E = 1500 K, the volume variation of diamond from room conditions to pressures and temperatures exceeding those in the Earth’s transition zone is described to within the levels of uncertainty inherent in both experimental and computational determinations. For the example of olivine inclusions in diamond, these uncertainties in the diamond EoS parameters lead to uncertainties in the entrapment pressures of no more than 0.001 GPa at low temperatures and 0.008 GPa at higher temperatures. |
DS201503-0133 2015 | Araujo e Azevedo, P., Peres Rocha, M., Pereira Soares, J.E., Fuck, R.A. | Thin lithosphere beween the Amazonian and Sao Francisco cratons, in central Brazil, revealed by seismic P wave tomography. | Geophysical Journal International, Vol. 201, 1, pp. 61-69. | South America, Brazil | Geophysics - seismic |
| Abstract: Results of P-wave traveltime seismic tomography in central Brazil unravel the upper-mantle velocity structure and its relationship with the tectonic framework. Data were recorded between 2008 and 2012 at 16 stations distributed over the study area, and were added to the database used by Rocha et al. to improve the resolution of anomalies, and to image the surrounding regions. The main objective was to observe the upper-mantle boundary zone between the Amazonian and São Francisco cratons, represented by mobile belts, inside the Tocantins Province, and to study the lithosphere related to the collision between these two cratons during the Neoproterozoic. A set of low-velocity anomalies was observed crossing the study area in the NE–SW direction, in agreement with the main trend of the Transbrasiliano lineament. The region where the anomalies are located was interpreted as the zone separating the Amazonian and São Franciscan palaeoplates. There is a good correlation between the low-velocity anomalies and the high seismicity of this region, suggesting that it is a region of weakness, probably related to lithospheric thinning. High velocities were observed under the Amazonian and São Francisco cratons. A model is proposed for the lithospheric subsurface in central Brazil, emphasizing the boundary zone between the main palaeoplates in the study area. After merging both databases, the low-velocity anomalies in the central part of the study area suggest tectonic partitioning of the lithosphere. Synthetic tests show that the tomography results are robust. |
DC201502-1392 2014 | Archangel Diamond Corp | Lukoil wins dismissal of USA lawsuit over alleged fraud. ( Archangel Diamond Company JV with Arkhangelgeology AGE) | OAO Lukoil , Dec. 23, 1p. | Russia | News item - press release |
DC201502-1393 2015 | Arctic Star Exploration Corporation | Arctic Star stakes Torrie kimberlite cluster at Lac de Gras. | Arctic Star Exploration, Jan. 16, 1p. | Canada, Northwest Territories | News item - press release |
DC201503-1395 2015 | Arctic Star Exploration Corporation | Arctic Star announces "Stein diamond project", Nunavut Canada. | Arctic Star Exploration Corporation, Feb. 5, 1p. | Canada, Nunavut | News item - press release |
DC201507-1394 2015 | Arctic Star Exploration Corporation | Arctic Star updates the Redemption diamond project, Lac de Gras. | Arctic Star Exploration, June 2, 1p. | Canada, Northwest Territories | News item - press release |
DC201509-1396 2015 | Arctic Star Exploration Corporation | Arctic Star reports on T-Rex property. | Arctic Star Exploration Corporation, Aug. 5, 4p. | Canada, Northwest Territories | News item - press release |
DS201510-1757 2014 | Arzamastev, A.A., Arztmasteva, L.V., Zhirova, A.M., Glaznev, V.N. | Model of formation of the Khibiny-Lovozero ore bearing volcanic-plutonic complex. | Deep-seated magmatism, its sources and plumes, Proceedings of XIII International Workshop held 2014., Vol. 2014, pp. 124-147. | Baltic Shield, Fennoscandia | Carbonatite, alkaline rocks |
| Abstract: The paper presents the results of a study of the large Paleozoic ore-magmatic system in the northeastern Fennoscandian Shield comprising the Khibiny and Lovozero plutons, the Kurga intrusion, volcanic rocks, and numerous alkaline dike swarms. As follows from the results of deep drilling and 3D geophysical simulation, large bodies of rocks pertaining to the ultramafic alkaline complex occur at the lower level of the ore-magmatic system. Peridotite, pyroxenite, melilitolite, melteigite, and ijolite occupy more than 50 vol % of the volcanic-plutonic complex within the upper 15 km accessible to gravity exploration. The proposed model represents the ore-magmatic system as a conjugate network of mantle magmatic sources localized at different depth levels and periodically supplying the melts belonging to the two autonomous groups: (1) ultramafic alkaline rocks with carbonatites and (2) alkali syenites-peralkaline syenites, which were formed synchronously having a common system of outlet conduits. With allowance for the available isotopic datings and new geochronological evidence, the duration of complex formation beginning from supply of the first batches of melt into calderas and up to postmagmatic events, expressed in formation of late pegmatoids, was no less than 25 Ma. |
DS201502-0039 2015 | Ashchepkov, I. | The universal Cpx Jd-Di barometer for mantle peridotite eclogite and pyroxenites and its use for mantle petrology. | Economic Geology Research Institute 2015, Vol. 17,, # 2121, 1p. Abstract | Technology | Barometer |
| Abstract: Original monomineral thermobarometers for mantle peridotites for clinopyroxene, garnet, chromite and ilmenites for the mantle peridotites were statistically calibrated on the PT estimates for mantle peridotites [Ashchepkov et al., 2010] were tested using the mineral phases obtained in high pressure experiments with the natural peridotites (380 runs) [Brey et al.,1990; 2008 etc] and eclogites (240 runs)[Dasgupta et al., 2006 etc]. In the original program of that written on FORTRAN are assembled the most reliable methods of mineral thermometers (45) and barometers (36) and oxybarometers (5), including original monomineral and methods [Ashchepkov, 2003 Ashchepkov et al., 2008; 2009; 2010; 2011] for the mantle peridotites bases on the compositions of on clinopyroxene, garnet, chromite and ilmenite. Program reads the text files, which converted from Excel. Original data include standard silicate compositions for 12 components in standard order. The text file includes 15 columns of 8 symbols. The first is file name which is the same for all the minerals in the association. The second is indicator symbol for phases. E- enstatite, D - diopside, O-olivine, S-spinel, G- garnet, I –ilmenite, A- amphibole, F – phlogopite, P-plagioclase, L- liquid, R- bulk rock. Then follow oxides: SiO2, TiO2, Al2O3, Cr2O3, FeO, MnO, MgO, CaO, Na2O, K2O, NiO, V2O3 written with 2–3 decimals. The last column may contain description of the mineral or association up to 64 symbols. Monomineral methods use calculated values for Fe#Ol or Fe#Cpx. The input from console includes file name (8 symbols) (A8), then amount of PT pairs of numbers thermometers and barometers (2I2) and one for FO2 method. Program allows input of the iteration numbers (to 25 by default). It allow to choose whether to use the calculated Fe3+ for the minerals and also. It is possible also to put fixed values of T and P (default 1000oC and 40 kbar ). |
DS201502-0040 2015 | Ashchepkov, I., Ntaflos, T., Spetsius, Z. | Trace element study of the xenoliths study of the mantle xenoliths from Sytykanskaya pipe, Yakutia. | Economic Geology Research Institute 2015, Vol. 17,, # 2624, 1p. Abstract | Russia | Deposit - Sytykanskaya |
DS201510-1758 2015 | Ashchepkov, I.V., Logvinova, A.M., Reimers, L.F., Ntaflos, T., Spetisus, Z.V., Vladykin, N.V., Downes, H., Yudin, D.S., Travin, A.V., Makovchuk, I.V., Palesskiy, V.S., KhmelNikova, O.S. | The Sytykanskaya kimberlite pipe: evidence from deep seated xenoliths and xenocrysts for the evolution of the mantle beneath Alakit, Yakutia, Russia. | Geoscience Frontiers, Vol. 6, 5, pp. 687-714. | Russia, Yakutia | Deposit - Sytykanskaya |
| Abstract: Mantle xenoliths (>150) and concentrates from late autolithic breccia and porphyritic kimberlite from the Sytykanskaya pipe of the Alakit field (Yakutia) were analyzed by EPMA and LAM ICP methods. In P-T-X-f(O2) diagrams minerals from xenoliths show widest variations, the trends P-Fe#-CaO, f(O2) for minerals from porphyric kimberlites are more stepped than for xenocrysts from breccia. Ilmenite PTX points mark moving for protokimberlites from the lithosphere base (7.5 GPa) to pyroxenite lens (5-3.5 GPa) accompanied by Cr increase by AFC and creation of two trends P-Fe#Ol ?10-12% and 13-15%. The Opx-Gar-based mantle geotherm in Alakit field is close to 35 mW/m2 at 65 GPa and 600 °C near Moho was determined. The oxidation state for the megacrystalline ilmenites is lower for the metasomatic associations due to reduction of protokimberlites on peridotites than for uncontaminated varieties at the lithosphere base. Highly inclined linear REE patterns with deep HFSE troughs for the parental melts of clinopyroxene and garnet xenocrysts from breccia were influenced by differentiated protokimberlite. Melts for metasomatic xenoliths reveal less inclined slopes without deep troughs in spider diagrams. Garnets reveal S-shaped REE patterns. The clinopyroxenes from graphite bearing Cr-websterites show inclined and inflected in Gd spectrums with LREE variations due to AFC differentiation. Melts for garnets display less inclined patterns and Ba-Sr troughs but enrichment in Nb-Ta-U. The 40Ar/39Ar ages for micas from the Alakit mantle xenoliths for disseminated phlogopites reveal Proterozoic (1154 Ma) age of metasomatism in early Rodinia mantle. Veined glimmerites with richterite - like amphiboles mark ?1015 Ma plume event in Rodinia mantle. The ?600-550 Ma stage manifests final Rodinia break-up. The last 385 Ma metasomatism is protokimberlite-related. |
DS201510-1759 2014 | Ashchepkov, I.V., Vladykin, N.V., Ntaflos, T., Logvinova, A.M., Yudin, D.S., Karpenko, M.A., Paleeskiy, V.S., Alymova, N.V., Khmelnikova, O.S. | Deep seated xenoliths and xencrysts from Sytykanskaya pipe: evidence for the evolution of the mantle beneath Alakit, Yakutia. | Deep-seated magmatism, its sources and plumes, Proceedings of XIII International Workshop held 2014., Vol. 2014, pp. 203-232. | Russia, Yakutia | Deposit - Sytykanskaya |
| Abstract: The concentrate from two phases of the kimberlite (breccia and porphyritic kimberlite) and about 130 xenoliths from the Sytykanskaya pipe of the Alakit field (Yakutia) were studied by EPMA and LAM ICP methods. Reconstructions of the PTXfO2 mantle sections were made separately for the two phases. The porphyritic kimberlites and breccia show differences in the minerals although the layering and pressure interval remains the same. For the porphyritic kimberlite the trends P- Fe# - CaO in garnet, fO2 are sub-vertical while the xenocrysts from the breccia show stepped and curved trends possibly due to interaction with fluids. Minerals within xenoliths show the widest variation in all pressure intervals. PT points for the ilmenites which trace the magmatic system show splitting of the magmatic source into two levels at the pyroxenite lens (4GPa) accompanied by peridotite contamination and an increase in Cr in ilmenites. Two groups of metasomatites with Fe#Ol ~ 10-12% and 13-15% were created by the melts derived from protokimberlites and trace the mantle columns from the lithosphere base (Ilm - Gar - Cr diopside) to Moho becoming essentially pyroxenitic (Cr-diopside with Phl). The first Opx-Gar-based mantle geotherm from the Alakit field has been constructed from15 associations and is close to 35 mw/m2 in the lower part of mantle section but deviates to high temperatures in the upper part of the mantle section. The oxidation state for the protokimberlite melts determined from ilmenites is higher than for the other pipes in the Yakutian kimberlite province which probably accounts for the decrease in the diamond grade of this pipe. The geochemistry of the minerals (garnets and clinopyroxenes) from breccias, metasomatic peridotite xenoliths and pyroxenites systematically differ. Xenocrysts from the breccia were produced by the most differentiated melts and enriched protokimberlite or carbonatite; they show highly inclined nearly linear REE patterns and deep troughs of HFSE. Minerals of the metasomatic xenoliths are less inclined with lower La/Cen ratios and without troughs in spider diagrams. The garnets often show S-shaped patterns. Garnets from the Cr websterites show round REE patterns and deep troughs in Ba-Sr but enrichment in Nb-Ta-U. The clinopyroxenes reveal the inclined and inflected on Gd spectrums with variations in LREE due to AFC differentiation. The 40Ar-39Ar ages for micas from the Alakit field reveal three intervals for the metasomatism. The first (1154 Ma) relates to dispersed phlogopites found throughout the mantle column, and probably corresponds to the continental arc stage in the early stage of Rodinia. Veined highly alkaline and Ti-rich veins with richterite ~1015 Ma corresponds to the plume event within the Rodinia mantle. The ~600-550 Ma stage marks the final Rodinia break-up. The last one near 385 Ma is protokimberlite related. |
DC201506-1397 2015 | Astro Resources nl | Highlights East Kimberley diamonds. | Astro Resources nl, Apr. 29, 1p. | Australia | News item - press release |
DC201509-1398 2015 | Astro Resources NL | East Kimberley diamonds project ( near Argyle AK1 pipe). Quarterly update | Astro Resources NL, July 30, 12p. | Australia | News item - press release |
DC201512-2414 2015 | Astro Resources nl | Drilling and geophysical dat a identified seven priority potential lamproite pipe targets. East Kimberley | Astro Resources nl, Oct. 27, 1p | Australia | News item - press release |
DC201502-1399 2015 | Athabasca Nuclear Corporation | Athabasca Nuclear options Pikoo North diamond project. | Athabasca Nuclear Corporation, Jan. 2, 1p. | Canada, Saskatchewan | News item - press release |
DC201510-2330 2015 | Athabasca Nuclear Corporation | Athabasca Nuclear Corporation announces commencement of Pikoo airborne survey. | Athabasca Nuclear Corporation, Sept. 16, 1p. | Canada, Saskatchewan | News item - press release |
DC201512-2415 2015 | Athabasca Nuclear Corporation | Prongua Lake project update. Airborne survey. | Athabasca Nuclear Corporation, Oct. 29, 1p. | Canada, Saskatchewan | News item - press release |
DC201512-2416 2015 | Athabasca Nuclear Corporation | Announces Pikoo airborne results at Prongua Lake. | Athabasca Nuclear Corporation, Nov. 17, 1p. | Canada, Saskatchewan | News item - press release |
DS201511-1820 2015 | Aulbach , S., Viljoen, K.S. | Eclogite xenoliths from the Lace kimberlite, Kaapvaal craton: from convecting mantle source to palaeo-ocean floor and back. | Earth and Planetary Science Letters, Vol. 431, pp. 274-286. | Africa, South Africa | Deposit - Lace |
| Abstract: Major- and trace-element compositions of eclogite and pyroxenite xenoliths of ?2.5 Ga age (in situ Pb-Pb data on clinopyroxene) from the Lace kimberlite on the Kaapvaal craton were investigated in order to constrain: (1) the nature and evolution of their protoliths; (2) the extent to which they preserve information on the state of the asthenospheric mantle source that gave rise to their low-pressure protoliths; and (3) the effect of their deep recycling on the radiogenic isotope evolution of the convecting mantle. Their elemental relationships are consistent with low-pressure fractionation of olivine ± plagioclase and clinopyroxene during oceanic crust formation, whereby the residual melt was enriched in rare-earth elements (REE), high field-strength elements and Y, producing inverse correlations of ?REE with the size of Eu- and Sr-anomalies. LREE-depletion may indicate loss of on average 20% of a partial melt upon subduction and metamorphism (eclogitisation) of oceanic crust, which did not, however, contribute to juvenile growth of continental crust. The eclogites have median Sm/Nd (0.40) and Lu/Hf (0.27) similar to Depleted Mantle, and lower U/Pb (0.02) and Th/Pb (0.02). If deeply subducted, these rocks cannot explain unradiogenic Nd and Hf, and radiogenic Pb isotope compositions in the sources of some modern ocean island basalts. Low incompatible trace-element contents similar to picrites, and Yb concentrations at a given TiO2 content similar to modern MORB, indicate derivation of the protoliths by average melt fractions of ?0.20-0.25?0.20-0.25 that left a spinel peridotite residue at pressures ?2.5 to 3.0 GPa. This shallow intersection of the peridotite solidus suggests moderate Archaean ambient mantle potential temperatures of ?1420 to 1470?°C. Samples filtered for clinopyroxene fractionation and metasomatism have V/Sc (4.7±1.24.7±1.2; n=11n=11) indicating lower fO2fO2 (?1.9 relative to the fayalite-magnetite-quartz buffer=?FMQbuffer=?FMQ) than modern MORB. This is in part due to the higher average melt extraction pressure (?1.5 GPa) during formation of their crustal protoliths. Extrapolation to 1 GPa, similar to the average pressure of present-day MORB generation, yields ?FMQ of ?1.7±1.1?1.7±1.1, corresponding to Fe3+# of 0.07±0.040.07±0.04. If these results are correct, they suggest an Archaean ambient mantle more reducing than at present, with implications for the speciation of volatiles, which affects the mantle solidus and the composition of volcanic gases. This has implications for the Archaean atmospheric redox evolution and the recycling of carbon and other volatiles. |
DS201501-0003 2015 | Ault, A.K., Flowers, R.M., Bowlring, S.A. | Synchroneity of cratonic burial phases and gaps in kimberlite record: episodic magmatism or preservational bias? | Earth and Planetary Science Letters, Vol. 410, pp. 97-104. | Global, Canada | Thermochronology - Slave craton |
| Abstract: A variety of models are used to explain an apparent episodicity in kimberlite emplacement. Implicit in these models is the assumption that the preserved kimberlite record is largely complete. However, some cratons now mostly devoid of Phanerozoic cover underwent substantial Phanerozoic burial and erosion episodes that should be considered when evaluating models for global kimberlite distributions. Here we show a broad temporal coincidence between regional burial phases inferred from thermochronology and gaps in the kimberlite record in the Slave craton, Superior craton, and cratonic western Australia. A similar pattern exists in the Kaapvaal craton, although its magmatic, deposition, and erosion history differs in key ways from the other localities. One explanation for these observations is that there is a common cause of cratonic subsidence and suppression of kimberlite magmatism. Another possibility is that some apparent gaps in kimberlite magmatism are preservational artifacts. Even if kimberlites occurred during cratonic burial phases, the largest uppermost portions of the pipes would have been subsequently eroded along with the sedimentary rocks into which they were emplaced. In this model, kimberlite magmatism was more continuous than the preserved record suggests, implying that evidence for episodicity in kimberlite genesis should be carefully evaluated in light of potential preservational bias effects. Either way, the correlation between burial and kimberlite gaps suggests that cratonic surface histories are important for understanding global kimberlite patterns. |
DS201511-1821 2012 | AusIMM JORC | Australasian code for reporting of exploration results, mineral resources and ore reserves. There is a mention of micros in this 2012 version. Tania has updated the next SAMREC version with alluivials and micros which may be available in 2016 and will b | JORC Ore Reserves Committee, 2012, 44p. Available pdf | Global | Microdiamonds - responses |
DM201504-0457 2015 | Australian Mining | Argyle pink diamond coin retailing for a cool $ 8k. | Australian Mining, Mar. 4, 1/4p. | Australia | News item - Argyle |
DS201501-0004 2014 | Bah, M.D. | Mining for peace: diamonds, bauxite, iron ore and political stability in Guinea. | Review of African Political Economy, Routledge Pub., Vol. 41, no. 142, pp. 500-515. | Africa, Guinea | History |
| Abstract: The article explores the relationship between mineral resources and conflict management in Guinea. Literature on theories of recent civil wars and/or armed conflicts in West Africa identifies the combination of abundant natural resources and extreme poverty as a significant trigger of violent civil conflicts. In Guinea, however, despite this combination, the state has managed to avoid large-scale civil violence. This gives rise to the question of why this combination has failed to be associated with the onset of large-scale violence in the country. The article identifies mitigating factors that have contributed to political stability in Guinea. It concludes that measures taken by Guinea and its international partners mitigated the security threats posed by these resources, while keeping most Guineans in abject poverty. This is in contrast to findings in recent quantitative studies whereby natural resource abundance alongside extreme poverty is strongly associated with armed conflicts in West African nations. |
DS201507-0303 2015 | Bailey, B.L., Blowes, D.W., Smith, L., Sego, D.C. | The Diavik waste rock project: geochemical and microbiological characterization of drainage from low sulfide waste rock: active zone field experiments. | Applied Geochemistry, Vol. 36, pp. 187-199. | Canada, Northwest Territories | Deposit - Diavik |
DS201512-1896 2015 | Bailey, B.L., Blowes, D.W., Smith, L., Sego, D.C. | The Diavik waste rock project: geochemical and microbiological characterization of low sulfide content large-scale waste rock test piles. | Applied Geochemistry, Vol. 62, pp. 18-34. | Canada, Northwest Territories | Deposit - Diavik |
| Abstract: Two experimental waste-rock piles (test piles), each 15 m in height × 60 m × 50 m, were constructed at the Diavik diamond mine in Northern Canada to study the behavior of low-sulfide content waste rock, with a similarly low acid-neutralization potential, in a continuous permafrost region. One test pile with an average of 0.035 wt.% S (<50 mm fraction; referred to as Type I) and a second test pile with an average of 0.053 wt.% S (<50 mm fraction; referred to as Type III) were constructed in 2006. The average carbon content in the <50 mm fraction of waste rock in the Type I test pile was 0.031 wt.% as C and in the Type III test pile was 0.030 wt.% as C. The NP:AP ratio, based on the arithmetic mean of particle-size weighted NP and AP values, for the Type I test pile was 12.2, suggesting this test pile was non-acid generating and for the Type III test pile was 2.2, suggesting an uncertain acid-generating potential. The Type I test pile maintained near-neutral pH for the 4-year duration of the study. Sulfate and dissolved metal concentrations were low, with the exception of Ni, Zn, Cd, and Co in the fourth year following construction. The pore water in the Type III test pile contained higher concentrations of SO42? and dissolved metals, with a decrease in pH to <4.7 and an annual depletion of alkalinity. Maximum concentrations of dissolved metals (20 mg L?1 Ni, 2.3 mg L?1 Cu, 3.7 mg L?1 Zn, 35 ?g L?1 Cd, and 3.8 mg L?1 Co) corresponded to decreases in flow rate, which were observed at the end of each field season when the contribution of the total outflow from the central portion of the test pile was greatest. Bacteria were present each year in spite of annual freeze/thaw cycles. The microbial community within the Type I test pile included a population of neutrophilic S-oxidizing bacteria. Each year, changes in the water quality of the Type III test-pile effluent were accompanied by changes in the microbial populations. Populations of acidophilic S-oxidizing bacteria and Fe-oxidizing bacteria became more abundant as the pH decreased and internal test pile temperatures increased. Irrespective of the cold-climate conditions and low S content of the waste rock, the geochemical and microbiological results of this study are consistent with other acid mine drainage studies; indicating that a series of mineral dissolution-precipitation reactions controls pH and metal mobility, and transport is controlled by matrix-dominated flow and internal temperatures. |
DS201501-0005 2014 | Bain & Company | The global diamond report 2014, Diamonds: timeless gems in a changing world. Challenges, financing, supply and demand | Bain & Company, 84p. Pdf available | Global | Diamond markets |
| Abstract: In this year’s edition: Diamonds: Timeless Gems in A Changing World, we focus on key challenges facing the industry, initiatives under way to address them, and possible outcomes that would support the industry’s continued growth. We believe that the challenges explored in this report also present opportunities for all players in the diamond industry and for the investment community. The key challenges include the following: Sustaining demand for diamonds in jewelry and as investments. What models of cooperation are players adopting to spur demand for diamonds, in jewelry and as an investment vehicle? Securing long-term access to diamonds. As long-term supply tapers off, what options can retailers consider? Defining the role of synthetic diamonds. What opportunities and challenges will the continued evolution of synthetic-diamond technologies present to the industry? Ensuring that diamond financing will continue to sustain industry growth. How should the diamond-financing business model evolve to sustain healthy growth for all industry players? As in previous years, the report also identifies key trends along the value chain for rough and polished diamonds as well as diamond jewelry. We compare 2013 results with the results of previous years and highlight the impact of continuing economic uncertainty on the diamond market. We also provide an update on the outlook for the diamond industry through 2024. The 2024 demand outlook is based on our extensive market analysis and research. The updated supply forecast is based on the latest developments among key diamond miners and the largest diamond mines worldwide. |
DS201505-0254 2015 | 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 Plateau | Convection |
| 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. |
DS201509-0384 2015 | Baptiste, V., Demouchy, S., Keshav, S., Parat, F., Bolfan-Casanova, N., Condamine, P., Cordier, P. | Decrease of hydrogen in corporation in forsterite from CO2-H2O rich kimberlitic liquid. | American Mineralogist, Vol. 100, pp. 1912-1920. | Technology | Hydrogen, water |
| Abstract: To test if hydrogen incorporation by ionic diffusion can occur between a volatile-rich kimberlitic liquid and forsterite, results of high-pressure and high-temperature experiments using a piston-cylinder apparatus at 1200–1300 °C and 1 GPa for durations of 1 min, 5 h, and 23 h, are reported here. Kim-berlitic liquid in the system CaO-MgO-Al 2 O 3-SiO 2-CO 2-H 2 O and synthetic forsterite single crystals were chosen as a first simplification of the complex natural kimberlite composition. Unpolarized Fourier transform infrared spectroscopy was used to quantify the concentrations of OH in the crystallographically oriented forsterite. Scanning electron microscopy, electron backscattered diffraction, electron microprobe analyses, and transmission electron microscopy were performed to identify the run products. After 5 and 23 h, a forsterite overgrowth crystallized with the same orientation as the initial forsterite single crystal. The kimberlitic liquid has crystallized as micrometer-scale euhedral forsterite neocrystals with random crystallographic orientations, as well as a nanoscale aluminous phase and a calcic phase. Despite theoretical water-saturation of the system and long duration, none of the initial forsterite single crystals display signs of hydration such as hydrogen diffusion profile from the border toward the center of the crystal. Most likely, the presence of CO 2 in the system has lowered the H 2 O fugacity to such an extent that there is no significant hydration of the starting forsterite single crystal or its overgrowth. Also, the presence of CO 2 enhances rapid forsterite crystal growth. Forsterite growth rate is around 2 × 10 8 mm 3 /h at 1250 °C. These experimental results suggest a deep mantle origin of the high OH content found in natural mantle-derived xenoliths transported in kimberlites, as reported from the Kaapvaal craton. In agreement with previous studies, it also points out to the fact that significant hydration must take place in a CO 2-poor environment. |
DS201504-0183 2015 | Barry, P.H., Hilton, D.R., Day, J.M.D., Pernet-Fisher, J.F., Howarth, G.H., Magna, T., Agashev, A.M., Pokhilenko, N.P., Opkhilenko, L.N., Taylor, L.A. | Helium isotope evidence for modification of the cratonic lithosphere during the Permo-Triassic Siberian flood basalt event. | Lithos, Vol. 216-217, pp. 73-80. | Russia, Siberia | Deposit - Udachnaya, Obnazhennaya |
| Abstract: Major flood basalt emplacement events can dramatically alter the composition of the sub-continental lithospheric mantle (SCLM). The Siberian craton experienced one of the largest flood basalt events preserved in the geologic record — eruption of the Permo-Triassic Siberian flood basalts (SFB) at ~250 Myr in response to upwelling of a deep-rooted mantle plume beneath the Siberian SCLM. Here, we present helium isotope (3 He/ 4 He) and concentra-tion data for petrologically-distinct suites of peridotitic xenoliths recovered from two temporally-separated kim-berlites: the 360 Ma Udachnaya and 160 Ma Obnazhennaya pipes, which erupted through the Siberian SCLM and bracket the eruption of the SFB. Measured 3 He/ 4 He ratios span a range from 0.1 to 9.8 R A (where R A = air 3 He/ 4 He) and fall into two distinct groups: 1) predominantly radiogenic pre-plume Udachnaya samples (mean clinopyroxene 3 He/ 4 He = 0.41 ± 0.30 R A (1?); n = 7 excluding 1 outlier), and 2) 'mantle-like' post plume Obnazhennaya samples (mean clinopyroxene 3 He/ 4 He = 4.20 ± 0.90 R A (1?); n = 5 excluding 1 outlier). Olivine separates from both kimberlite pipes tend to have higher 3 He/ 4 He than clinopyroxenes (or garnet). Helium con-tents in Udachnaya samples ([He] = 0.13–1.35 ?cm 3 STP/g; n = 6) overlap with those of Obnazhennaya ([He] = 0.05–1.58 ?cm 3 STP/g; n = 10), but extend to significantly higher values in some instances ([He] = 49– 349 ?cm 3 STP/g; n = 4). Uranium and thorium contents are also reported for the crushed material from which He was extracted in order to evaluate the potential for He migration from the mineral matrix to fluid inclusions. The wide range in He content, together with consistently radiogenic He-isotope values in Udachnaya peridotites suggests that crustal-derived fluids have incongruently metasomatized segments of the Siberian SCLM, whereas high 3 He/ 4 He values in Obnazhennaya peridotites show that this section of the SCLM has been overprinted by Permo-Triassic (plume-derived) basaltic fluids. Indeed, the stark contrast between pre-and post-plume 3 He/ 4 He ra-tios in peridotite xenoliths highlights the potentially powerful utility of He-isotopes for differentiating between various types of metasomatism (i.e., crustal versus basaltic fluids). |
DS201511-1822 2015 | Bartels, A., Nielsen, T.F.D., Lee, S.R.G.J., Upton, B.G.J. | Petrological and geochemical characteristics of Mesoproterozoic dyke swarms in the Gardar Province, south Greenland: evidence for a major sub-continental lithospheric mantle component in the generation of the magmas. | Mineralogical Magazine, Vol. 79, 4, pp. 909-939. | Europe, Greenland | Dike swarms |
| Abstract: The Mesoproterozoic Gardar Province in South Greenland developed in a continental rift-related environment. Several alkaline intrusions and associated dyke swarms were emplaced in Archaean and Ketilidian basement rocks during two main magmatic periods at 1300-1250 Ma and 1180-1140 Ma. The present investigation focuses on mafic dykes from the early magmatic period (‘Older Gardar’) and the identification of their possible mantle sources. The rocks are typically fine- to coarse-grained dolerites, transitional between tholeiitic and alkaline compositions with a general predominance of Na over K. They crystallized from relatively evolved, mantle-derived melts and commonly show minor degrees of crustal contamination. Selective enrichment of the large ion lithophile elements Cs, Ba and K and the light rare-earth elements when compared to high field-strength elements indicate significant involvement of a sub-continental lithospheric mantle (SCLM) component in the generation of the magmas. This component was affected by fluid-dominated supra-subduction zone metasomatism, possibly related to the Ketilidian orogeny ~500 Ma years prior to the onset of Gardar magmatism. Melt generation in the SCLM is further documented by the inferential presence of amphibole in the source region, negative calculated ?Nd(i) values (?0.47 to ?4.40) and slightly elevated 87Sr/86Sr(i) (0.702987 to 0.706472) ratios when compared to bulk silicate earth as well as relatively flat heavy rare-earth element (HREE) patterns ((Gd/Yb)N = 1.4-1.9) indicating melt generation above the garnet stability field. The dyke rocks investigated show strong geochemical and geochronological similarities to pene-contemporaneous mafic dyke swarms in North America and Central Scandinavia and a petrogenetic link is hypothesized. Considering recent plate reconstructions, it is further suggested that magmatism was formed behind a long-lived orogenic belt in response to back-arc basin formation in the time interval between 1290-1235 Ma. |
DS201511-1823 2004 | Barton, E. | Small is beautiful… the recovery of microdiamonds helps to predict the presence of commercial sized diamonds. | Inside Mining, Vol. 109, July, pp. 32-35. Available pdf | Africa | Microdiamonds - responses |
| Abstract: The recovery and analysis of microdiamonds helps to predict the presence of commercial-sized diamonds in kimberlites. It is a cost-effective method for prioritising targets for bulk sampling. |
DS201503-0136 2015 | Bastow, I.D., Eaton, D.W., Kendall, J-M., Helffrich, G., Snyder, D.B., Thompson, D.A., Wookey, J., Darbyshire, F.A., Pawlak, A.E. | The Hudson Bay lithospheric experiment ( HuBLE): insights into Precambrian plate tectonics and the development of mantle keels. | Geological Society of London Special Publication: Continent formation through time., No. 389, pp. 41-67. | Canada, Ontario, Quebec | Geotectonics |
| Abstract: Hudson Bay Lithospheric Experiment (HuBLE) was designed to understand the processes that formed Laurentia and the Hudson Bay basin within it. Receiver function analysis shows that Archaean terranes display structurally simple, uniform thickness, felsic crust. Beneath the Palaeoproterozoic Trans-Hudson Orogen (THO), thicker, more complex crust is interpreted as evidence for a secular evolution in crustal formation from non-plate-tectonic in the Palaeoarchaean to fully developed plate tectonics by the Palaeoproterozoic. Corroborating this hypothesis, anisotropy studies reveal 1.8 Ga plate-scale THO-age fabrics. Seismic tomography shows that the Proterozoic mantle has lower wavespeeds than surrounding Archaean blocks; the Laurentian keel thus formed partly in post-Archaean times. A mantle transition zone study indicates ‘normal’ temperatures beneath the Laurentian keel, so any cold mantle down-welling associated with the regional free-air gravity anomaly is probably confined to the upper mantle. Focal mechanisms from earthquakes indicate that present-day crustal stresses are influenced by glacial rebound and pre-existing faults. Ambient-noise tomography reveals a low-velocity anomaly, coincident with a previously inferred zone of crustal stretching, eliminating eclogitization of lower crustal rocks as a basin formation mechanism. Hudson Bay is an ephemeral feature, caused principally by incomplete glacial rebound. Plate stretching is the primary mechanism responsible for the formation of the basin itself. |
DS201502-0041 2014 | Batanova, V.G., Lyaskovskaya, Z.E., Savelieva, G.N., Sobolev, A.V. | Peridotites from the Kamchatsky Mys: evidence of oceanic mantle melting near a hotspot. | Russian Geology and Geophysics, Vol. 55, pp. 1395-1403. | Russia | Harzburgite, plumes |
| Abstract: A suite of mantle peridotites sampled in the Kamchatsky Mys includes spinel lherzolite, clinopyroxene-bearing harzburgite, and harzburgite. Mineral chemistry of olivine, chromian spinel, and clinopyroxene show strongly correlated element patterns typical of peridotite formed by 8% to more than 22% partial melting. Clinopyroxene in the Kamchatka peridotites is compositionally different from that of both abyssal and suprasubduction varieties: Clinopyroxene in lherzolite is depleted in LREE relative to abyssal peridotite and that in harzburgite has very low LREE and Sr unlike the subduction-related counterpart. These composition features indicate that the rocks ultra-depleted in basaltic components originated in the vicinity of a hotspot, possibly, proto-Hawaiian plume, which provided high temperature and melting degree of the MORB source mantle at mid-ocean ridge. |
DM201501-0458 2014 | Bates, R. | Believe it: the lab-grown diamond sector is out promoting the natural diamonds. | jckonline.com, Dec. 12, 1p. | Technology | News item - Pure Grown |
DM201502-0459 2015 | Bates, R. | Being a sightholder is a fool's errand. | JSCK Online blog, Jan. 23, 1p. | Global | News item - De Beers |
DC201509-1400 2015 | Bauer Foundations Canada Inc. | Bauer Group acquires major project to build cut-off wall for diamond mine in Canada. Diavik | Bauer Foundations Canada Inc., Aug. 1p. | Canada, Northwest Territories | News item - press release |
DC201503-1401 2015 | Beaufort Securities | Paragon Diamonds … emerging diamond producer with polished upside, fully funded. Lemphane | Beaufort Securities Research Report, Feb. 12, 6p. | Africa, Lesotho | News item - Paragon |
DS201512-1897 2015 | Belcourt, G. | A 2015 geophysical update for Kennady North project, NT. | 43rd Annual Yellowknife Geoscience Forum Abstracts, abstract p. 16. | Canada, Northwest Territories | Deposit - Kennady North |
| Abstract: This presentation will provide an update of geophysical surveys performed in 2015. These surveys were undertaken to aid in the delineation of known kimberlites and discovery of potential kimberlite targets on Kennady Diamonds Inc.'s Kennady North Property. In 2015, Kennady Diamonds Inc. focused most of their geophysical budget on expansion of the known kimberlites. Previous OhmMapper surveys were expanded in the Doyle & MZ Areas in order to provide locations for exploration drilling. Ground based Gravity surveys were completed using an increased sample density in key areas. This increased density in the gravity data proved to be very helpful in the detailed drilling of the Kelvin and Faraday kimberlite bodies. Late in the summer season, a small scale marine seismic system was utilized on the Kelvin and Faraday lakes. This data will hopefully be used to discover potential areas of new or thicker kimberlite under the lake. As the Kelvin and Faraday kimberlites are not the typical pipe-like bodies, many different geophysical tools from our toolbox must be utilized. |
DS201506-0256 2015 | Bell, K., Zaitsev, A.N., Spratt, J., Frojdo, S., Rukhlov, A.S. | Elemental, lead and sulfur isotopic compositions of galena from Kola carbonatites, Russia - implications for melt and mantle evolution. | Mineralogical Magazine, Vol. 79, 2, pp. 219-241. | Russia | Carbonatite, Kola |
| Abstract: Galena from four REE-rich (Khibina, Sallanlatvi, Seblyavr, Vuoriyarvi) and REE-poor (Kovdor) carbonatites, as well as hydrothermal veins (Khibina) all from the Devonian Kola Alkaline Province of northwestern Russia was analysed for trace elements and Pb and S isotope compositions. Microprobe analyses show that the only detectable elements in galena are Bi and Ag and these vary from not detectable to 2.23 and not detectable to 0.43 wt.% respectively. Three distinct galena groups can be recognized using Bi and Ag contents, which differ from groupings based on Pb isotope data. The Pb isotope ratios show significant spread with 206Pb/204Pb ratios (16.79 to 18.99), 207Pb/204Pb (15.22 to 15.58) and 208Pb/204Pb ratios (36.75 to 38.62). A near-linear array in a 207Pb/204Pb vs. 206Pb/204Pb ratio diagram is consistent with mixing between distinct mantle sources, one of which formed during a major differentiation event in the late Archaean or earlier. The S isotopic composition (?34S) of galena from carbonatites is significantly lighter (–-6.7 to -–10.3% Canyon Diablo Troilite (CDT) from REE-rich Khibina, Seblyavr and Vuoriyarvi carbonatites, and - 3.2% CDT from REE-poor Kovdor carbonatites) than the mantle value of 0%. Although there is no correlation between S and any of the Pb isotope ratios, Bi and Ag abundances correlate negatively with ?34S values. The variations in the isotopic composition of Pb are attributed to partial melting of an isotopically heterogeneous mantle source, while those of ?34S (together with Bi and Ag abundances) are considered to be process driven. Although variation in Pb isotope values between complexes might reflect different degrees of interaction between carbonatitic melts and continental crust or metasomatized lithosphere, the published noble gas and C, O, Sr, Nd and Hf isotopic data suggest that the variable Pb isotope ratios are best attributed to isotopic differences preserved within a sub-lithospheric mantle source. Different Pb isotopic compositions of galena from the same complex are consistent with a model of magma replenishment by carbonatitic melts/fluids each marked by quite different Pb isotopic compositions. |
DS201505-0249 2015 | Belogub, E.V., Krivovichev, S.V., Pekov, I.V., Kuznetsov, A.M., Yapaskurt, V.O., Kitlyarov, V.A., Chukanov, N.V., Belakoviskiy, D.I. | Nickelpicromerite, K2Ni(SO4)2*6H2O, a new picromerite group mineral from Slyudorudnik, South Urals, Russia. | Mineralogy and Petrology, Vol. 109, 2, pp. 143-152. | Russia, Urals | Mineralogy |
| Abstract: A new picromerite-group mineral, nickelpicromerite, K2Ni(SO4)2 - 6H2O (IMA 2012-053), was found at the Vein #169 of the Ufaley quartz deposit, near the town of Slyudorudnik, Kyshtym District, Chelyabinsk area, South Urals, Russia. It is a supergene mineral that occurs, with gypsum and goethite, in the fractures of slightly weathered actinolite-talc schist containing partially vermiculitized biotite and partially altered sulfides: pyrrhotite, pentlandite, millerite, pyrite and marcasite. Nickelpicromerite forms equant to short prismatic or tabular crystals up to 0.07 mm in size and anhedral grains up to 0.5 mm across, their clusters or crusts up to 1 mm. Nickelpicromerite is light greenish blue. Lustre is vitreous. Mohs hardness is 2-2½. Cleavage is distinct, parallel to {10-2}. Dmeas is 2.20(2), Dcalc is 2.22 g cm?3. Nickelpicromerite is optically biaxial (+), ? = 1.486(2), ? = 1.489(2), ? = 1.494(2), 2Vmeas =75(10)°, 2Vcalc =76°. The chemical composition (wt.%, electron-microprobe data) is: K2O 20.93, MgO 0.38, FeO 0.07, NiO 16.76, SO3 37.20, H2O (calc.) 24.66, total 100.00. The empirical formula, calculated based on 14 O, is: K1.93Mg0.04Ni0.98S2.02O8.05(H2O)5.95. Nickelpicromerite is monoclinic, P21/c, a = 6.1310(7), b = 12.1863(14), c = 9.0076(10) Å, ? = 105.045(2)°, V = 649.9(1) Å3, Z = 2. Eight strongest reflections of the powder XRD pattern are [d,Å-I(hkl)]: 5.386--34(110); 4.312-46(002); 4.240-33(120); 4.085--100(012, 10-2); 3.685-85(031), 3.041-45(040, 112), 2.808-31(013, 20-2, 122), 2.368-34(13-3, 21-3, 033). Nickelpicromerite (single-crystal X-ray data, R = 0.028) is isostructural to other picromerite-group minerals and synthetic Tutton’s salts. Its crystal structure consists of [Ni(H2O)6]2+ octahedra linked to (SO4)2? tetrahedra via hydrogen bonds. K+ cations are coordinated by eight anions. Nickelpicromerite is the product of alteration of primary sulfide minerals and the reaction of the acid Ni-sulfate solutions with biotite. |
DS201511-1824 2015 | Bergantz, G.W., Schleicher, J.M., Burgisser, A. | Open system dynamics and mixing in magma mushes. | Nature Geoscience, Vol. 8, 10, pp. 793-796. | Mantle | Magmatism |
| Abstract: Magma dominantly exists in a slowly cooling crystal-rich or mushy state1, 2, 3. Yet, observations of complexly zoned crystals4, some formed in just one to ten years5, 6, 7, 8, 9, as well as time-transgressive crystal fabrics10 imply that magmas mix and transition rapidly from a locked crystal mush to a mobile and eruptable fluid5, 6. Here we use a discrete-element numerical model that resolves crystal-scale granular interactions and fluid flow, to simulate the open-system dynamics of a magma mush. We find that when new magma is injected into a reservoir from below, the existing magma responds as a viscoplastic material: fault-like surfaces form around the edges of the new injection creating a central mixing bowl of magma that can be unlocked and become fluidized, allowing for complex mixing. We identify three distinct dynamic regimes that depend on the rate of magma injection. If the magma injection rate is slow, the intruded magma penetrates and spreads by porous media flow through the crystal mush. With increasing velocity, the intruded magma creates a stable cavity of fluidized magma that is isolated from the rest of the reservoir. At higher velocities still, the entire mixing bowl becomes fluidized. Circulation within the mixing bowl entrains crystals from the walls, bringing together crystals from different parts of the reservoir that may have experienced different physiochemical environments and leaving little melt unmixed. We conclude that both granular and fluid dynamics, when considered simultaneously, can explain observations of complex crystal fabrics and zoning observed in many magmatic systems. |
DS201504-0184 2015 | Berryman, E.J., Wunder, B., Wirth, R., Rhede, D., Schettler, G., Franz, G., Heinrich, W. | An experimental study on K and Na in corporation in dravitic tourmaline and insight into the origin of Diamondiferous tourmaline from the Kokchetav Massif, Kazakhstan. | Contributions to Mineralogy and Petrology, Vol. 169, 19p. | Russia, Kazakhstan | Diamondiferous tourmaline |
| Abstract: Tourmaline was synthesized in the system MgO-Al2O3-B2O3-SiO2-KCl-NaCl-H2O from an oxide mixture and excess fluid at 500-700 °C and 0.2-4.0 GPa to investigate the effect of pressure, temperature, and fluid composition on the relative incorporation of Na and K in dravitic tourmaline. Incorporation of K at the X-site increases with pressure, temperature, and KCl concentration; a maximum of 0.71 K pfu (leaving 0.29 X-vacant sites pfu) was incorporated into K-dravite synthesized at 4.0 GPa, 700 °C from a 4.78 m KCl, Na-free fluid. In contrast, Na incorporation depends predominately on fluid composition, rather than pressure or temperature; dravite with the highest Na content of 1.00 Na pfu was synthesized at 0.4 GPa and 700 °C from a 3.87 m NaCl and 1.08 m KCl fluid. All synthesized crystals are zoned, and the dominant solid solution in the Na- and K-bearing system is between magnesio-foitite [?(Mg2Al)Al6Si6O18(BO3)3(OH)3OH] and dravite [NaMg3Al6Si6O18(BO3)3(OH)3(OH)], with the dravitic component increasing with the concentration of Na in the fluid. In the K-bearing, Na-free system, the dominant solid solution is between magnesio-foitite and K-dravite [KMg3Al6Si6O18(BO3)3(OH)3(OH)], with the K-dravitic component increasing with pressure, temperature, and the concentration of K in the fluid. The unit-cell volume of tourmaline increases with K incorporation from 1555.1(3) to 1588.1(2) Å3, reflecting the incorporation of the relatively large K+ ion. Comparison of our results to the compositional data for maruyamaite (K-dominant tourmaline) from the ultrahigh-pressure rocks of the Kokchetav Massif in Kazakhstan suggests that the latter was formed in a K-rich, Na-poor environment at ultrahigh-pressure conditions near the diamond-stability field. |
DS201510-1760 2015 | Beyer, C. | Geobarometry, phase relations and elasticity of eclogite under conditions of Earth's upper mantle. IN ENGLISH | Thesis, Doctoral Beyreuther Graduiertenschule fur Mathematik und Naturwissenschaften IN: ENGLISH, 222p. Available pdf | Mantle | Geobarometry |
| Abstract: Eclogite rocks, composed mainly of garnet and clinopyroxene, form principally as a metamorphic product of oceanic crust as it undergoes subduction. The equilibrium between garnet and clinopyroxene is sensitive to temperature and pressure, therefore eclogitic outcrops and xenoliths can reveal important information on the chemical and mineralogical processes occurring during such episodes. This is particularly the case for lithospheric eclogitic xenoliths from Archean cratons, which can potential reveal information on ancient (> 1 Ga) subduction events. To obtain information on the depth of origin of eclogitic xenoliths the first project of this thesis was designed to establish a thermodynamically grounded geobarometer, which is based on the incorporation of tetrahedrally coordinated aluminum in clinopyroxene coexisting with garnet: 2/3 Ca3Al2Si3O12 + 1/3 Mg3Al2Si3O12 = CaAl2SiO6 + CaMgSi2O6 Grossular Pyrope CaTs Diopside The reaction was calibrated against high-pressure and high-temperature experiments carried out in the multi-anvil and piston-cylinder apparatus between pressures of 3 and 7 GPa and temperatures from 1200 to 1550 °C. Starting materials were hydrous and anhydrous synthetic mixtures of basaltic bulk compositions that yielded homogeneous bimineralic garnet-clinopyroxene phase assemblages. The experimental data set was expanded by employing results from previous experimental studies conducted in eclogitic systems, which widened the range of applicable conditions and compositions. The calibration reproduces experimental pressures of bimineralic eclogite assemblages, in addition to SiO2-saturated and kyanite-bearing eclogites, to within 0.4 GPa at the 95 % confidence interval. The barometer was then used to examine equilibration pressures recorded by natural mantle eclogites from various xenolith locations covering a wide pressure, temperature, and compositional range. The results seem to indicate that many eclogite xenoliths fall towards the hotter side of the range of geothermal temperatures displayed by peridotitic xenoliths from the same localities. The second project calibrates the composition of majoritic garnets, which contain excess silicon substituted onto the octahedrally coordinated garnet site, coexisting with clinopyroxene as a function of pressure, temperature and bulk composition. Majorite substitution for a given bulk composition increases with pressure, and its proportion can in principal be used as a geobarometer. Single majoritic garnet crystals are found as inclusions in diamonds, which are generally used to support a sublithospheric origin in the deeper upper mantle or transition zone. The chemical compositions of such inclusions indicate that they have formed from a number of different lithologies, including mafic, ultramafic and pyroxenitic. These inclusions give important insight into the environment where diamonds crystallize and the evolution of deep subducted crustal material. The empirical barometer studied here is based on the three major majoritic substitutions: 2Al3+ = Mg2+ + Si4+ (Mj), Mg2+ + Al3+ = Na1+ + Si4+ (NaSi), Mg2+ + Al3+ = Na1+ + Ti4+ (NaTi), and the secondary effect of chromium on the stability of Mj. The barometer was calibrated against experiments conducted in the multi-anvil apparatus between pressures of 6 and 16 GPa and temperatures of 1000 to 1400 °C. In order to expand the applicability to a wide range of compositions experiments were performed in three different mafic compositions and in one pyroxenitic composition. Moreover, existing experimental data in mafic and ultramafic systems, including mid-ocean ridge basalts, kimberlite, komatiite and peridotite bulk compositions were included in the calibration covering pressures from 6 to 20 GPa and temperatures from 900 to 2200 °C. Applying the geobarometer to natural majoritic diamond inclusions reveals clearly that eclogitic and pyroxenitic inclusions form dominantly at conditions near the top of the transition zone (300-400 km). Peridotitic inclusions, however, have formed generally at shallower depths ~200 km within the Earth’s upper mantle. This may reflect the differences expected for the oxygen fugacity between peridotitic and eclogitic/pyroxenitic rocks. If diamonds form through the reduction of carbonate or CO2 bearing melts then most peridotitic rocks would be already within the diamond stability field by depths of 200 km. At greater pressures carbon would remain immobilized as diamond and there is no mechanism by which new diamonds can form. Eclogitic rocks formed by the subduction of oceanic crust, however, should form an intrinsically more oxidized environment that remains within the carbonate stability field to much higher pressures. The diamond stability field would be eventually reached, however, due to either the effect of pressure on controlling Fe3+/Fe2+ equilibria or due to partial melting, which would preferentially remove ferric iron and lower the Fe3+/?Fe of the residue, on which the oxygen fugacity is mainly dependent. In fact deep partial melting as slabs heat up may be the mechanism by which both the local oxygen fugacity is lowered, carbon is mobilized and pyroxenite rocks are formed, with the latter occurring through reaction with the surrounding peridotite. The third project was focused on the elasticity of garnet solid solutions formed from eclogitic compositions. Garnet is an important mineral because it is a major phase in the upper mantle and dominates mafic rocks at these conditions. The elastic behavior of garnet solid solutions plays a role in the interpretation of seismic data and is important for estimating the density contrast between subducting slabs and the surrounding mantle. High-precision single-crystal X-ray diffraction measurements at high pressure have been conducted on three different ternary garnet solid solutions with varying chemical composition in order to examine possible non-ideal contributions to the volume and compressibility of garnet solid solutions. Furthermore one experiment has been conducted at high pressures and high temperatures to examine the effect of temperature on the elasticity of complex garnet solid solutions. Experimental results reveal that the concentration of the almandine (Fe3Al2Si3O12) component has a significant effect on the elasticity, whereby 10 - 20 mole% of almandine is sufficient to overprint the previously reported minima of the bulk modulus along the pyrope grossular join. It has also been shown that minor compositional variations of Ca and Mg within the Mg Fe Ca garnet ternary are not resolvable within the analytical errors. Therefore, the two eclogitic samples have similar bulk moduli within the analytical uncertainties. In contrast to previous studies, no evidence was found that garnets have a K’ significantly different from 4. The high-temperature experiment revealed that the relatively small fraction of almandine in a solid solution increased the softening of garnet with temperature. Finally, the experimental volumes and calculated densities have been compared to the self-consistent thermodynamic model of Stixrude and Lithgow-Bertelloni (2005, 2011). The comparison clearly reveals that volume and elastic properties cannot be linearly interpolated as a function of composition. Moreover, it has been shown that the excess properties vary not only as a function of composition and pressure, but also as a function of temperature. The final project is focused on the partitioning of fluorine (F) between garnet, clinopyroxene, and silicate melt within eclogitic compositions. Fluorine is the most abundant halogen on Earth and plays an important role in the formation of ultrapotassic lithologies, i.e. lamproites that contain several wt.% F, in contrast to the average lithospheric mantle that contains only tens of µg/g F. The cycling and partitioning behavior of fluorine in the Earth’s mantle are not well understood. High-pressure experiments have been conducted in the multi-anvil apparatus to obtain mineral-melt partition coefficients between garnet, clinopyroxene, and coexisting silicate melt of fluorine in a mafic system under conditions of the Earth’s upper mantle. The results show that mafic crust can host significantly more fluorine than the surrounding ultramafic mantle, due to the much higher proportion of clinopyroxene and its high fluorine partition coefficient of D_F^(clinopyroxene/melt)= 0.057 - 0.074. Combining the fluorine partitioning data with water partitioning data yields a plausible process to generate lamproitic magmas with a high F/H2O ratio. The enrichment of fluorine relative to H2O is triggered by multiple episodes of small degree melting which deplete the residual more in H2O than in fluorine, caused by the approximately three times smaller mineral-melt partition coefficients of H2O. |
DS201503-0134 2015 | Beyer, C., Frost, D.J., Miyajima, N. | Experimental calibration of a garnet-clinopyroxene geobarometer for mantle eclogites. | Contributions to Mineralogy and Petrology, Vol. 169, 21p. | Mantle | Geobarometry - eclogites |
| Abstract: Thermodynamic parameters have been calibrated for a geobarometer suitable for use on eclogitic mantle xenoliths. The barometer is based on the incorporation of tetrahedrally coordinated aluminum in clinopyroxene coexisting with garnet and has been calibrated using the results of piston cylinder and multi-anvil experiments performed between pressures of 3 and 7 GPa and temperatures from 1,200 to 1,550 °C. Starting materials were hydrous and anhydrous synthetic mixtures of basaltic bulk compositions that yielded homogeneous bimineralic garnet-clinopyroxene phase assemblages. The experimental data set was expanded by employing results from previous experimental studies conducted in eclogitic systems, which widened the range of applicable conditions and compositions. The calibration reproduces experimental pressures of bimineralic eclogite assemblages, in addition to SiO2-saturated and kyanite-bearing eclogites, to within 0.4 GPa at the 95 % confidence interval. The barometer was then used to examine equilibration pressures recorded by natural mantle eclogites from various xenolith locations covering a wide pressure, temperature, and compositional range. |
DM201508-0460 2015 | Biesheuver, T. | The missing diamond shortage. | Bloomberg.news, July 3, 3p. | Global | News item - markets |
DS201512-1898 2015 | Blacklock, S. | Ekati diamond mine UAVs. | 43rd Annual Yellowknife Geoscience Forum Abstracts, abstract p. 18. | Canada, Northwest Territories | Deposit - Ekati |
| Abstract: Dominion Diamond Ekati Corporation (DDEC) purchased two unmanned aerial vehicles (UAV's) in 2014 to assist in surveying the active open pits and kimberlite stockpiles at the mine. UAV technology has allowed the team to survey various aspects of the mine in a safer and more accurate. manner. Along with making day to day work more efficient, DDEC surveying now has the ability to complete various other requests from departments at the mine. These include; large area photographs of lay downs, new road alignments, projects and environmental areas of interest. |
DS201504-0185 2015 | 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, Ghana | Geochronology |
| 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. |
DS201502-0042 2015 | Bloodworth, A. | The high stakes race to satisfy our need for the scarcest metals on Earth. Book by K. Veronese Publ. Prometheus | Nature, Vol. 517, 7533, Jan. 8, pp. 142-143. | Global | Book review - REE |
DM201502-0461 2015 | Bloomberg | X-ray scanners ordered by Debswana to catch Botswana gem thieves. Jwaneng, Orapa, Letlhakane and Damtshaa. | bloomberg.com, Jan. 6, 1p. | Africa, Botswana | News item - Debswana |
DM201502-0462 2015 | Bloomberg | Israel gem buyers scared of De Beers profit squeeze. | bloomberg.com, Jan. 21, 1p. | Europe, Israel | News item - De Beers |
DM201502-0463 2015 | Bloomberg | Namibia resumes diamond sales talks with Anglo's De Beers unit. | bloomberg.com, Jan. 22, 1p. | Africa, Namibia | News item - Namdeb |
DM201509-0464 2015 | Bloomberg | Want to make a diamond in just 10 weeks? Use a microwave. | bloomberg.com, Aug. 27, 2p. | Technology | News item - synthetics |
DM201512-2214 2015 | Bloomberg | Diamonds aren't forever for Botswana as mining boom fades. | bloomberg.com, Nov. 5, 1p. | Africa, Botswana | News item - economics |
DM201512-2215 2015 | Bloomberg | Was billionaire Steinmetz betrayed by CEO over diamond mine? Koidu | bloomberg.com, Nov. 11, 5p. | Africa, Sierra Leone | News item - Steinmetz |
DM201509-1999 2015 | Bluedax.com | Rough market report: July sight - is the system bankrupt. | Idex online, July 26, 2p. | Global | News item - sights |
DS201512-1899 2015 | Bluemel, B., Dunn, C., Hart, C., Leijd, M. | Biogeochemical expressions of buried REE mineralization at Norra Karr, southern Sweden. | Symposium on critical and strategic materials, British Columbia Geological Survey Paper 2015-3, held Nov. 13-14, pp. 231-240. | Technology | Rare earths |
| Abstract: Biogeochemical exploration is an effective but underutilized method for delineating covered mineralization. Plants are capable of accumulating rare earth elements (REEs) in their tissue, and ferns (pteridophytes) are especially adept because they are one of the most primitive land plants, therefore lack the barrier mechanisms developed by more evolved plants. The Norra Kärr Alkaline Complex, located in southern Sweden approximately 300km southwest of Stockholm, is a peralkaline nepheline syenite enriched in heavy rare earth elements (HREEs). The deposit, roughly 300m wide, 1300m long, and overlain by up to 4 m of Quaternary sediments, has been well-defined by diamond drilling. The inferred REE mineral resource, over 60 million tonnes averaging 0.54% Total Rare Earth Oxide (TREO), is dominantly hosted within the pegmatitic “grennaite” unit, a eudialyte-catapleiite-aegerine nepheline syenite. Vegetation and soil samples were collected from the surficial environment above Norra Kärr to address four key questions: which plant species is the most effective biogeochemical exploration medium; what are the annual and seasonal REE variations in that plant; how do the REEs move through the soil profile; and into which part of the plant are they concentrated. Athyrium filix-femina (lady fern) has the highest concentration of LREEs and HREEs (up to 125.17ppm Ce and 1.03ppm Dy) in its dry leaves; however, there is better contrast between background and anomalous areas in Dryopteris filix-mas (wood fern), which makes it the preferred biogeochemical sampling medium. The REE content in all fern species was shown to decrease from root > frond > stem, and chondrite normalized REE patterns within the plant displayed preferential fractionation of the LREEs in the fronds relative to the roots. Samples collected from an area directly overlying the deposit had up to five times greater HREE content (0.74ppm Dy) in August than the same plants did in June (0.14ppm Dy). The elevated REE content and distinct contrast to background demonstrate that biogeochemical sampling is an effective method for REE exploration in this environment. |
DC201506-1403 2015 | BlueRock Diamonds Plc. | BlueRock Diamonds' Kareevlei plant delayed by crusher commissioning. | BlueRock Diamonds Plc., May 1, 1p. | Africa, South Africa | News item - press release |
DC201507-1404 2015 | BlueRock Diamonds plc. | Blue Rock Diamonds sells 116 carat parcel for average of USD440 per carat. | Bluerock Diamonds plc., June 25, 1p. | Africa, South Africa | News item - press release |
DC201511-2370 2015 | BlueRock Diamonds plc. | Interim results .. Summary Kareevlei Wes kimberlite. | BlueRock Diamonds plc., Sept. 30, 3p. | Africa, South Africa | News item - press release |
DC201512-2417 2015 | BlueRock Diamonds plc. | Finalization of contract with Diacar and operational update.. Kareevlei | BlueRock Diamonds Plc, Nov. 5, 1p. | Africa, South Africa | News item - press release |
DS201509-0385 2015 | 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, Madagascar | Tectonics |
| 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. |
DS201502-0043 2015 | Bogina, M., Zlobin, V., Sharkov, E., Chistyakov, A. | Petrogenesis of siliceous high-Mg series rocks as exemplified by the Early Paleoproterozoic mafic volcanic rocks of the Eastern Baltic Shield: enriched mantle versus crustal contamination. | Economic Geology Research Institute 2015, Vol. 17,, #3510, 1p. Abstract | Russia | Plume geodynamics |
| Abstract: The Early Paleoproterozoic stage in the Earth's evolution was marked by the initiation of global rift systems, the tectonic nature of which was determined by plume geodynamics. These processes caused the voluminous emplacement of mantle melts with the formation of dike swarms, mafic-ultramafic layered intrusions, and volcanic rocks. All these rocks are usually considered as derivatives of SHMS (siliceous high-magnesian series). Within the Eastern Baltic Shield, the SHMS volcanic rocks are localized in the domains with different crustal history: in the Vodlozero block of the Karelian craton with the oldest (Middle Archean) crust, in the Central Block of the same craton with the Neoarchean crust, and in the Kola Craton with a heterogeneous crust. At the same time, these rocks are characterized by sufficiently close geochemical characteristics: high REE fractionation ((La/Yb)N = 4.9-11.7, (La/Sm)N=2.3-3.6, (Gd/Yb)N =1.66-2.74)), LILE enrichment, negative Nb anomaly, low to moderate Ti content, and sufficiently narrow variations in Nd isotope composition from -2.0 to -0.4 epsilon units. The tectonomagmatic interpretation of these rocks was ambiguous, because such characteristics may be produced by both crustal contamination of depleted mantle melts, and by generation from a mantle source metasomatized during previous subduction event. Similar REE patterns and overlapping Nd isotope compositions indicate that the studied basaltic rocks were formed from similar sources. If crustal contamination en route to the surface would play a significant role in the formation of the studied basalts, then almost equal amounts of contaminant of similar composition are required to produce the mafic rocks with similar geochemical signatures and close Nd isotopic compositions, which is hardly possible for the rocks spaced far apart in a heterogeneous crust. This conclusion is consistent with analysis of some relations between incompatible elements and their ratios. In particular, the rocks show no correlation between Th/Ta and La/Yb, (Nb/La)pm ratio and Th content, and eNd and (Nb/La)N ratio. At the same time, some correlation observed in the eNd-Mg# and (La/Sm)N-(Nb/La)N diagrams in combination with the presence of inherited zircons in the rocks does not allow us to discard completely the crustal contamination. Examination of Sm/Yb-La/Sm relations and the comparison with model melting curves for garnet and spinel lherzolites showed that the parental melts of the rocks were derived by 10-30% mantle melting at garnet-spinel facies transition. Two stage model can be proposed to explain such remarkable isotope-geochemical homogeneity of the mafic volcanic rocks over a large area: (1) ubiquitous emplacement of large volumes of sanukitoid melts in the lower crust of the shield at 2.7 Ga; (2) underplating of plume-derived DM melts at the crust-mantle boundary, melting of the lower crust of sanukitoid composition, and subsequent mixing of these melts with formation of SHMS melts at 2.4 Ga. A simple mixing model showed that in this case the Nd isotope composition of obtained melts remained practically unchanged at variable amounts of contaminant (up to 30%). This work was supported by the RFBR no. 14-05-00458. |
DS201502-0044 2015 | Bonetto, S., Facello, A., Ferrero, A-M., Umili, G. | A tool for semi-automatic linear feature detection based on DTM. | Computers & Geosciences, Vol. 75, pp. 1-12. | Technology | Not specific to diamonds |
DM201502-0465 2015 | Bonner, H. | Hason Stevens: why I believe diamonds are a good 5 year play. | Sprottglobal.com, Jan.12, 4p. Graphs | Global | News item - demand |
DS201511-1825 2014 | Bosshart, G., Chapman, J. | The Argyle diamond mine in transition from open pit to underground extraction. | Australian Gemmologist, Vol. 24, 1, pp. 4-8. | Australia | Deposit - Argyle |
| Abstract: At the Argyle diamond mine in Western Australia, an underground project is using block caving techniques to reach deeper portions of the diamondiferous lamproite. This program could extend the life of the mine to 2018. It entails a high level of automation, as well as measures to combat monsoonal downpours. |
DC201504-1405 2015 | Botswana Diamonds plc. | Field exploration update - Orapa, Botswana ( Alrosa). PL 206,207,210 | Botswana Diamonds plc., Mar. 5, 2p. | Africa, Botswana | News item - press release |
DC201504-1406 2015 | Botswana Diamonds plc. | New licence in Orapa, Botswana. PL 085/2015 to Atlas Minerals ( the local subsidiary company) | Botswana Diamonds plc., Mar. 24, 1p. | Africa, Botswana | News item - press release |
DC201505-1407 2015 | Botswana Diamonds plc. | Interim results for the six months to 31 December 2014. JV Alrosa | Botswana Diamonds plc., Mar. 27, 3p. | Africa, Botswana | News item - press release |
DC201505-1408 2015 | Botswana Diamonds plc. | Botswana Diamonds Plc. Fundraising of lbs 282,500. | Botswana Diamonds plc., Mar. 31, 1p. | Africa, Botswana | News item - press release |
DC201505-1409 2015 | Botswana Diamonds plc. | Botswana Diamonds expands exploration with three new licences in the central part of Botswana. ( Alrosa) | Botswana Diamonds plc., Apr. 15, 1p. | Africa, Botswana | News item - press release |
DC201507-1410 2015 | Botswana Diamonds plc. | Exploration update - June 2015. Field work .. Anomaly PL210/2014 drill programme and more work on PL206 & 207. Alrosa | Botswana Diamonds plc., June 18, 1p. | Africa, Botswana | News item - press release |
DC201510-2331 2015 | Botswana Diamonds plc. | Update on exploration in Botswana. Orapa region .. PL 206, PL 210, PL 085 and then on to Gope region. | Botswana Diamonds plc, Sept. 3, 2p. | Africa, Botswana | News item - press release |
DC201510-2332 2015 | Botswana Diamonds plc. | Exploration update: Joint Venture with Alrosa, drilling starting on PL210, work on new Gope prospecting licences | Botswana Diamonds plc, Sept. 11, 2p. | Africa, Botswana | News item - Botswana Diamonds, Alrosa |
DC201511-2371 2015 | Botswana Diamonds plc. | Exploration update on Licence PL 210 drilling in Orapa. | Botswana Diamonds plc., Oct. 7, 1p. | Africa, Botswana | News item - press release |
DC201511-2372 2015 | Botswana Diamonds plc. | New prospecting licence awarded in the Orapa region of Botswana PL260/2015 to Sunland Minerals ( JV Alrosa) | Botswana Diamonds plc., Oct. 9, 1p. | Africa, Botswana | News item - press release |
DC201512-2418 2015 | Botswana Diamonds plc. | Preliminary results for the year ended 30 June 2015. | Botswana Diamonds plc., Nov. 19, 13p. | Africa, Botswana | News item - press release |
DS201503-0135 2015 | Bouhifd, M.A., Boyet, M., Cartier, C., Hammouda, T., Bofan-Casanova, N., Devidal, J.L., Andrault, D. | Superchondritic Sm/Nd ratio of the Earth: impact of Earth's core formation. | Earth and Planetary Science Letters, Vol. 413, March 1, pp. 158-166. | Mantle | Geochronology |
| Abstract: This study investigates the impact of Earth's core formation on the metal-silicate partitioning of Sm and Nd, two rare-earth elements assumed to be strictly lithophile although they are widely carried by the sulphide phases in reducing material (e.g. enstatite chondrites). The partition coefficients of Sm and Nd (DSmDSm and DNdDNd) between molten CI and EH chondrites model compositions and various Fe-rich alloys (in the Fe-Ni-C-Si-S system) have been determined in a multi-anvil between 3 and 26 GPa at various temperatures between 2073 and 2440 K, and at an oxygen fugacity ranging from 1 to 5 log units below the iron-wüstite (IW) buffer. The chemical compositions of the run products and trace concentrations in Sm and Nd elements were determined using electron microprobe and laser ablation inductively coupled plasma-mass spectrometry. Our results demonstrate the non-fractionation of Sm and Nd during the segregation of the metallic phases: the initial Sm/Nd ratio of about 1 in the starting materials yields precisely the same ratio in the recovered silicate phases after the equilibration with the metal phases at all conditions investigated in this study. In addition, DSmDSm and DNdDNd values range between 10?310?3 and 10?510?5 representing a low solubility in the metal. An increase of the partition coefficients is observed with decreasing the oxygen fugacity, or with an increase of S content of the metallic phase at constant oxygen fugacity. Thus, based on the actual Sm and Nd concentrations in the bulk Earth, the core should contain less than 0.4 ppb for Sm and less than 1 ppb for Nd. These estimates are three orders of magnitude lower than what would be required to explain the reported 142Nd excess in terrestrial samples relative to the mean chondritic value, using the core as a Sm-Nd complementary reservoir. In other words, the core formation processes cannot be responsible for the increase of the Sm/Nd ratio in the mantle early in Earth history. |
DS201511-1826 2015 | Boyd, O.S., Smalley, R., Zeng, Y. | Crustal deformation in the New Madrid seismic zone and the role of postseismic processes. | Journal of Geophysical Research, Vol. 120, 8, pp. 5782-5803. | United States, Arkansas | Geophysics - seismics |
| Abstract: Global Navigation Satellite System data across the New Madrid seismic zone (NMSZ) in the central United States over the period from 2000 through 2014 are analyzed and modeled with several deformation mechanisms including the following: (1) creep on subsurface dislocations, (2) postseismic frictional afterslip and viscoelastic relaxation from the 1811–1812 and 1450 earthquakes in the NMSZ, and (3) regional strain. In agreement with previous studies, a dislocation creeping at about 4 mm/yr between 12 and 20 km depth along the downdip extension of the Reelfoot fault reproduces the observations well. We find that a dynamic model of postseismic frictional afterslip from the 1450 and February 1812 Reelfoot fault events can explain this creep. Kinematic and dynamic models involving the Cottonwood Grove fault provide minimal predictive power. This is likely due to the smaller size of the December 1811 event on the Cottonwood Grove fault and a distribution of stations better suited to constrain localized strain across the Reelfoot fault. Regional compressive strain across the NMSZ is found to be less than 3?×?10?9/yr. If much of the present-day surface deformation results from afterslip, it is likely that many of the earthquakes we see today in the NMSZ are aftershocks from the 1811–1812 New Madrid earthquakes. Despite this conclusion, our results are consistent with observations and models of intraplate earthquake clustering. Given this and the recent paleoseismic history of the region, we suggest that seismic hazard is likely to remain significant. |
DS201506-0257 2015 | Bradley, D. | The promise of perovskite ( solar) | Chemistry Views, May 5, 2p. | Technology | Energy |
DS201502-0045 2014 | Brazil diamond map | Map of diamonds from the Patos Meeting. | Mapa Simposio APL Diamantes A3 QT.pdf, pdf available 12306K | South America, Brazil | Diamond locations in A.P. |
DC201503-1411 2015 | Brazil Minerals Inc. | Receives title to 25% of a company with 10 mining concessions for diamond and gold. RST Recursos Minerals, Ltda. | Brazil Minerals, Inc., Feb. 22, 1p. | South America, Brazil | News item - press release |
DC201504-1412 2015 | Brazil Minerals Inc. | Extinguishes 46% of convertible debt note. | Brazil Minerals, Inc., Mar. 9, 1p. | South America, Brazil | News item - press release |
DC201505-1413 2015 | Brazil Minerals Inc. | Brazil Minerals, Inc. reports largest rough diamond & expected further cash flows from sand products. | Brazil Minerals, Inc., Apr. 6, 1p. | South America, Brazil | News item - press release |
DC201506-1414 2015 | Brazil Minerals Inc. | Strong preliminary result for new diamond and gold area. Along the margins of Jequithonha River. | Brazil Minerals, Inc., Apr. 27, 1p. | South America, Brazil | News item - press release |
DC201506-1415 2015 | Brazil Minerals Inc. | Brazil Minerals, Inc. completes first phase of geological assessment of new diamond & gold area. Jequitinhonha river. | Brazil Minerals, Inc., May 26, 2p. | South America, Brazil, Minas Gerais | News item - press release |
DC201508-1416 2015 | Brazil Minerals Inc. | Brazil Minerals, Inc. receives environmental permit for mining in new diamond and gold area. Jequitinhonka River ( In land old course). | Brazil Minerals, Inc., July 13, 1p. | South America, Brazil | News item - press release |
DC201509-1417 2015 | Brazil Minerals Inc. | Finishes second phase of geological assessment of new diamond and gold area & completes payment for its RST ownership position. | Brazil Minerals, Inc., Aug. 3, 2p. | South America, Brazil | News item - press release |
DC201510-2333 2015 | Brazil Minerals Inc. | Brazil Minerals, Inc. provides general update. Comments on gravel potential. | Brazil Minerals, Inc., Sept. 21, 1p. | South America, Brazil | News item - press release |
DC201512-2419 2015 | Brazil Minerals Inc. | Provides updates on new access road and agreement with investor group to purchase outstanding convertible debt. | Brazil Minerals, Inc., Nov. 3, 1p. | South America, Brazil | News item - press release |
DS201507-0305 2015 | Brett, R.C. | The ascent of kimberlite: insights from olivine. | Earth and Planetary Science Letters, Vol. 424, pp. 119-131. | Canada, Northwest Territories, Africa, Tanzania | Deposit - Diavik, Igwisi Hills |
| Abstract: Olivine xenocrysts are ubiquitous in kimberlite deposits worldwide and derive from the disaggregation of mantle-derived peridotitic xenoliths. Here, we provide descriptions of textural features in xenocrystic olivine from kimberlite deposits at the Diavik Diamond Mine, Canada and at Igwisi Hills volcano, Tanzania. We establish a relative sequence of textural events recorded by olivine during magma ascent through the cratonic mantle lithosphere, including: xenolith disaggregation, decompression fracturing expressed as mineral- and fluid-inclusion-rich sealed and healed cracks, grain size and shape modification by chemical dissolution and abrasion, late-stage crystallization of overgrowths on olivine xenocrysts, and lastly, mechanical milling and rounding of the olivine cargo prior to emplacement. Ascent through the lithosphere operates as a "kimberlite factory" wherein progressive upward dyke propagation of the initial carbonatitic melt fractures the overlying mantle to entrain and disaggregate mantle xenoliths. Preferential assimilation of orthopyroxene (Opx) xenocrysts by the silica-undersaturated carbonatitic melt leads to deep-seated exsolution of CO2-rich fluid generating buoyancy and supporting rapid ascent. Concomitant dissolution of olivine produces irregular-shaped relict grains preserved as cores to most kimberlitic olivine. Multiple generations of decompression cracks in olivine provide evidence for a progression in ambient fluid compositions (e.g., from carbonatitic to silicic) during ascent. Numerical modelling predicts tensile failure of xenoliths (disaggregation) and olivine (cracks) over ascent distances of 2-7 km and 15-25 km, respectively, at velocities of 0.1 to >4 m?s?1. Efficient assimilation of Opx during ascent results in a silica-enriched, olivine-saturated kimberlitic melt (i.e. SiO2 >20 wt.%) that crystallizes overgrowths on partially digested and abraded olivine xenocrysts. Olivine saturation is constrained to occur at pressures <1 GPa; an absence of decompression cracks within olivine overgrowths suggests depths <25 km. Late stage (<25 km) resurfacing and reshaping of olivine by particle-particle milling is indicative of turbulent flow conditions within a fully fluidized, gas-charged, crystal-rich magma. |
DS201509-0386 2015 | Brey, G.P., Girnis, A.V., Bulatov, V.K., Hofer, H.E., Gerdes, A., Woodland, A.B. | Reduced sediment melting at 7.5-12 Gpa: phase relations, geochemical signals and diamond nucleation. | Contributions to Mineralogy and Petrology, Vol. 170, 25p. | Technology | Experimental petrology |
| Abstract: Melting of carbonated sediment in the presence of graphite or diamond was experimentally investigated at 7.5–12 GPa and 800–1600 °C in a multianvil apparatus. Two starting materials similar to GLOSS of Plank and Langmuir (Chem Geol 145:325–394, 1998) were prepared from oxides, carbonates, hydroxides and graphite. One mixture (Na-gloss) was identical in major element composition to GLOSS, and the other was poorer in Na and richer in K (K-gloss). Both starting mixtures contained ~6 wt% CO2 and 7 wt% H2O and were doped at a ~100 ppm level with a number of trace elements, including REE, LILE and HFSE. The near-solidus mineral assemblage contained a silica polymorph (coesite or stishovite), garnet, kyanite, clinopyroxene, carbonates (aragonite and magnesite-siderite solid solution), zircon, rutile, bearthite and hydrous phases (phengite and lawsonite at <9 GPa and the hydrous aluminosilicates topaz-OH and phase egg at >10 GPa). Hydrous phases disappear at ~900 °C, and carbonates persist up to 1000-1100 °C. At temperatures >1200 °C, the mineral assemblage consists of coesite or stishovite, kyanite and garnet. Clinopyroxene stability depends strongly on the Na content in the starting mixture; it remains in the Na-gloss composition up to 1600 °C at 12 GPa, but was not observed in K-gloss experiments above 1200 °C. The composition of melt or fluid changes gradually with increasing temperature from hydrous carbonate-rich (<10 wt% SiO2) at 800-1000 °C to volatile-rich silicate liquids (up to 40 wt% SiO2) at high temperatures. Trace elements were analyzed in melts and crystalline phases by LA ICP MS. The garnet-melt and clinopyroxene-melt partition coefficients are in general consistent with results from the literature for volatile-free systems and silicocarbonate melts derived by melting carbonated peridotites. Most trace elements are strongly incompatible in kyanite and silica polymorphs (D < 0.01), except for V, Cr and Ni, which are slightly compatible in kyanite (D > 1). Aragonite and Fe-Mg carbonate have very different REE partition coefficients (D Mst-Sd/L ~ 0.01 and D Arg/L ~ 1). Nb, Ta, Zr and Hf are strongly incompatible in both carbonates. The bearthite/melt partition coefficients are very high for LREE (>10) and decrease to ~1 for HREE. All HFSE are strongly incompatible in bearthite. In contrast, Ta, Nb, Zr and Hf are moderately to strongly compatible in ZrSiO4 and TiO2 phases. Based on the obtained partition coefficients, the composition of a mobile phase derived by sediment melting in deep subduction zones was calculated. This phase is strongly enriched in incompatible elements and displays a pronounced negative Ta-Nb anomaly but no Zr-Hf anomaly. Although all experiments were conducted in the diamond stability field, only graphite was observed in low-temperature experiments. Spontaneous diamond nucleation and the complete transformation of graphite to diamond were observed at temperatures above 1200-1300 °C. We speculate that the observed character of graphite-diamond transformation is controlled by relationships between the kinetics of metastable graphite dissolution and diamond nucleation in a hydrous silicocarbonate melt that is oversaturated in C. |
DC201502-1418 2014 | Britannia Mining Inc. | Diamonds in transit to north east initiate precious stones commodities contract. | Britannia Mining, Inc., Dec. 22, 1p. | Technology | News item - press release |
DC201505-1419 2015 | Britannia Mining Inc. | Announces two key hires for its diamond division ( Commodities trading division) | Britannia Mining, Inc., Mar. 31, 1p. | United States | News item - press release |
DS201502-0046 2014 | Brown, R., Summerfield, M., Gleadow, A., Gallagher, K., Carter, A., Beucher, R., Wildman, M. | Intracontinental deformation in southern Africa during the Late Cretaceous. | Journal of African Earth Sciences, Vol. 100, pp. 20-41. | Africa, Namibia | Geothermometry |
| Abstract: Intracontinental deformation accommodated along major lithospheric scale shear zone systems and within associated extensional basins has been well documented within West, Central and East Africa during the Late Cretaceous. The nature of this deformation has been established by studies of the tectonic architecture of sedimentary basins preserved in this part of Africa. In southern Africa, where the post break-up history has been dominated by major erosion, little evidence for post-break-up tectonics has been preserved in the onshore geology. Here we present the results of 38 new apatite fission track analyses from the Damara region of northern Namibia and integrate these new data with our previous results that were focused on specific regions or sections only to comprehensively document the thermo-tectonic history of this region since continental break-up in the Early Cretaceous. The apatite fission track ages range from 449 ± 20 Ma to 59 ± 3 Ma, with mean confined track lengths between 14.61 ± 0.1 ?m (SD 0.95 ?m) to 10.83 ± 0.33 ?m (SD 2.84 ?m). The youngest ages (c. 80–60 Ma) yield the longest mean track lengths, and combined with their spatial distribution, indicate major cooling during the latest Cretaceous. A simple numerical thermal model is used to demonstrate that this cooling is consistent with the combined effects of heating caused by magmatic underplating, related to the Paraná-Etendeka continental flood volcanism associated with rifting and the opening of the South Atlantic, and enhanced erosion caused by major reactivation of major lithospheric structures within southern Africa during a key period of plate kinematic change that occurred in the South Atlantic and SW Indian ocean basins between 87 and 56 Ma. This phase of intraplate tectonism in northern Namibia, focused in discrete structurally defined zones, is coeval with similar phases elsewhere in Africa and suggests some form of trans-continental linkage between these lithospheric zones. |
DS201507-0306 2015 | Brushan, S.K. | Geology of the Kamthai rare earth deposit. | Journal of the Geological Society of India, Vol. 85, 5, pp. 537-546. | India, Rajasthan | Calciocarbonatite |
| Abstract: A wide spectrum of calciocarbonatites and associated alkaline rocks are exposed around Kamthai, Rajasthan. The mineralogical studies exhibit a bimodal distribution of REE minerals. The southeastern block has carbocernaite and the eastern block has bastnaesite ± ancylite / synchysite as the dominant REE minerals followed by parisite and other accessory minerals. Calcite is the most abundant of the gangue phase, followed by biotite, albite, k-feldspar and iron oxide / hydroxide. Minor and trace gangue phases include pyrite, ilmenite, apatite, siderite, ankerite, amphibole, pyroxene, strontianite, barite, ilmenite / pyrophanite, celestine, clay minerals, sphalerite, pyrochlore, fluorite and Mn-rich phases including hollandite and Mn-Fe oxides. Calciocarbonatite occuring as intrusive veins, sills/dykes and plug, is perhaps a product of crystallization of a primary carbonatite melt generated at upper mantle. The first phase magmatic calciocarbonatite is alvikite type, rich in carbocernaite whereas second hydrothermal phase, sovite type, is enriched in bastnaesite. The absence of supergene activity and minerals (crandalite, florencite, gorceixite) indicate minor role of secondary enrichment. A rift-related mechanism, thermal equivalent to Deccan flood basalt (65±2 Ma), invoking "Reunion plume - continental hot spot" might have triggered Tertiary alkaline magmatism. |
DS201507-0307 2015 | Bucher, K., Stober, I., Muller-Sigmund, H. | Weathering crusts on peridotite. | Contributions to Mineralogy and Petrology, Vol. 169, pp. 52- | Europe, Spain | Deposit - Ronda |
| Abstract: Chemical weathering of dark-green massive peridotite, including partly serpentinized peridotite, produces a distinct and remarkable brown weathering rind when exposed to the atmosphere long enough. The structure and mineral composition of crusts on rocks from the Ronda peridotite, Spain, have been studied in some detail. The generic overall weathering reaction serpentinized peridotite + rainwater = weathering rind + runoff water describes the crust-forming process. This hydration reaction depends on water supply from the outcrop surface to the reaction front separating green peridotite from the brown crust. The reaction pauses after drying and resumes at the front after wetting. The overall net reaction transforms olivine to serpentine in a volume-conserving replacement reaction. The crust formation can be viewed as secondary serpentinization of peridotite that has been strongly altered by primary hydrothermal serpentinization. The reaction stoichiometry of the crust-related serpentinization is preserved and reflected by the composition of runoff waters in the peridotite massif. The brown color of the rind is caused by amorphous Fe(III) hydroxide, a side product from the oxidation of Fe(II) released by the dissolution of fayalite component in olivine. |
DS201512-1900 2015 | Burnham, A.D., Thomson, A.R., Bulanova, G.P., Kohn, S.C., Smith, C.B., Walter, M.J. | Stable isotope evidence for crustal recycling as recorded by superdeep diamonds. | Earth and Planetary Science Letters, Vol. 432, pp. 374-380. | South America, Brazil | Deposit - Juina-5, Collier-4, Machado River |
| Abstract: Sub-lithospheric diamonds from the Juina-5 and Collier-4 kimberlites and the Machado River alluvial deposit in Brazil have carbon isotopic compositions that co-vary with the oxygen isotopic compositions of their inclusions, which implies that they formed by a mixing process. The proposed model for this mixing process, based on interaction of slab-derived carbonate melt with reduced (carbide- or metal-bearing) ambient mantle, explains these isotopic observations. It is also consistent with the observed trace element chemistries of diamond inclusions from these localities and with the experimental phase relations of carbonated subducted crust. The 18O-enriched nature of the inclusions demonstrates that they incorporate material from crustal protoliths that previously interacted with seawater, thus confirming the subduction-related origin of superdeep diamonds. These samples also provide direct evidence of an isotopically anomalous reservoir in the deep (?350 km) mantle. |
DS201504-0186 2015 | Burtseva, M.V., Ripp, G.S., Posokhov, V.F., Zyablitsev, A.Yu., Murzintseva, A.E. | The sources of fluids for the formation of nephritic rocks of the southern folded belt of the Siberian craton. | Doklady Earth Sciences, Vol. 460, 1, pp. 82-86. | Russia, Siberia | Alkaline rocks, nephrites |
DM201502-0466 2015 | Business Standard | Rio Tinto strikes diamonds in Bundelkhand's Bunder. | business standard.com, Jan. 8, 1p. | India | News item - Rio Tinto |
DS201502-0047 2015 | Buslov, M.M., Dobretsov, N.L., Vovna, G.M., Kiselev, V.I. | Structural location, composition, and geodynamic nature of diamond bearing metamorphic rocks of the Kokchetav subduction-collision zone of the Central Asian Fold Belt ( Northern Kazakhstan). | Russian Geology and Geophysics, Vol. 56, 1-2, pp. 64-80. | Russia, Kazakhstan | Kokchetav massif |
| Abstract: We present data on different aspects of geology, mineralogy, petrology, geochemistry, and geochronology of diamond-bearing metamorphic rocks of the Kumdy-Kol terrane, which show the similarity of their protolith to the sedimentary rocks of the Kokchetav microcontinent. The structural location of the studied objects in the accretion-collision zone evidences that the subduction of the Kokchetav microcontinent beneath the Vendian-Cambrian Ishim-Selety island arc is the main mechanism of transport of graphite-bearing terrigenous-carbonate rocks to zones of their transformation into diamond-bearing metamorphic rocks. The sedimentary rocks of the Kokchetav microcontinent, which are enriched in graphite and iron sulfides and carbonates, contain all components necessary for diamond crystallization in deep-seated subduction zone. This is in agreement with the experimental data and the compositions of fluid-melt inclusions in the minerals of diamond-bearing rocks. |
DS201504-0187 2015 | 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 Territories | Deposit - 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.%). |
DS201512-1901 2015 | Butler, R. | Destructive sampling ethics… protect natural sites, rock outcrops… code of ethics. | Nature Geoscience, Vol. 8, 11, pp. 817-818. | Global | CSR |
DS201511-1827 2015 | Cai, Y-C., Fan, H-R., Santsh, M., Hu, F-F., Yang, K-F, Hu, Z. | Subduction related metasomatism of the lithospheric mantle beneath the southeastern North Chin a Craton: evidence from mafic to intermediate dykes in the northern Sulu orogen. | Tectonophysics, Vol. 659, pp. 137-151. | China | Sulu orogen - dykes |
| Abstract: The widespread mafic to intermediate dykes in the northern Sulu orogen provide important constrains on mantle source characteristics and geodynamic setting. Here we present LA-ICPMS zircon U-Pb ages which indicate that the dykes were emplaced during Early Cretaceous (~ 113-108 Ma). The rocks show SiO2 in the range of 46.2 to 59.5 wt.% and alkalic and shoshonitic affinity with high concentrations of MgO (up to 7.6 wt.%), Cr (up to 422 ppm) and Ni (up to 307 ppm). They are enriched in light rare earth elements LREE (La, Ce, Pr, Nd, Sm and Eu) and large ion lithophile elements (LILE, Rb, Sr, Ba, U and Th) and show strong depletion in high field strength elements (HFSE, Nb, Ta, Ti and P). The dykes possess uniformly high (87Sr/86Sr)i (0.70824-0.70983), low ?Nd(t) (? 14.0 to ? 17.4) and (206Pb/204Pb)i (16.66-17.02) and negative ?Hf(t) (? 23.5 to ? 13.7). Our results suggest that the source magma did not undergo any significant crustal contamination during ascent. The systematic variation trends between MgO and major and trace elements suggest fractionation of olivine and clinopyroxene. The highly enriched mantle source for these rocks might have involved melts derived from the subducted lower crust of Yangtze Craton that metasomatized the ancient lithospheric mantle of the North China Craton. |
DS201509-0387 2015 | Campeny, M., Kamenetsky, V.S., Melgarejo, J.C., Mangas, J., Manuel, J., Alfonso, P., Kamenetsky, M.B., Bambi, A.C.J.M., Goncalves, A.O. | Carbonatitic lavas in CatAnd a ( Kwanza Sul, Angola): mineralogical and geochemical constraints on the parental melt. | Lithos, Vol. 232, pp. 1-11. | Africa, Angola | Carbonatite |
| Abstract: A set of small volcanic edifices with tuff ring and maar morphologies occur in the Catanda area, which is the only locality with extrusive carbonatites reported in Angola. Four outcrops of carbonatite lavas have been identified in this region and considering the mineralogical, textural and compositional features, we classify them as: silicocarbonatites (1), calciocarbonatites (2) and secondary calciocarbonatites produced by the alteration of primary natrocarbonatites (3). Even with their differences, we interpret these lava types as having been a single carbonatite suite related to the same parental magma. We have also estimated the composition of the parental magma from a study of melt inclusions hosted in magnetite microphenocrysts from all of these lavas. Melt inclusions revealed the presence of 13 different alkali-rich phases (e.g., nyerereite, shortite, halite and sylvite) that argues for an alkaline composition of the Catanda parental melts. Mineralogical, textural, compositional and isotopic features of some Catanda lavas are also similar to those described in altered natrocarbonatite localities worldwide such as Tinderet or Kerimasi, leading to our conclusion that the formation of some Catanda calciocarbonatite lavas was related to the occurrence of natrocarbonatite volcanism in this area. On the other hand, silicocarbonatite lavas, which are enriched in periclase, present very different mineralogical, compositional and isotopic features in comparison to the rest of Catanda lavas. We conclude that its formation was probably related to the decarbonation of primary dolomite bearing carbonatites. |
DC201506-1420 2015 | Canadian International Minerals Inc. | Kimberlite indicator minerals recovered from Pikoo East properties. | Canadian International Minerals Inc., Apr. 27, 2p. | Canada, Saskatchewan | News item - press release |
DC201509-1421 2015 | Canadian International Minerals Inc. | Acquires Arc diamond project. Southwest of Pikoo field. ( Mountain Province and Consolidated Pine Channel Gold previous worked) | Canadian International Minerals Inc., Aug. 21, 2p. | Canada, Saskatchewan | News item - press release |
DC201510-2334 2015 | Canadian International Minerals Inc. | Fixed wing magnetic survey to be flown on Pikoo East properties. | Canadian International Minerals Inc., Sept. 14, 2p. | Canada, Saskatchewan | News item - press release |
DC201510-2335 2015 | Canadian Mining Journal | Diamonds, NWT, and how the Polar Bear got in there. Logo and diamond policy framework mentions Gahcho Kue. | Canadain Mining Journal, Sept. p. 8. | Canada, Northwest Territories | News item - Diamond Policy Framework |
DC201504-1422 2015 | CanAlaska Uranium Ltd. | CanAlaska Uranium reports on multiple projects Maguire Lake. | CanAlaska Uranium Ltd., Mar. 2, 1p. | Canada, Manitoba | News item - press release |
DC201502-1423 2015 | Canterra Minerals Corporation | Canterra stakes the Rex property, NT. | Canterra Minerals Corporation, Jan. 20, 1p. | Canada, Northwest Territories | News item - press release |
DC201503-1424 2015 | Canterra Minerals Corporation | Canterra receives preliminary gravity survey dat a for Marlin project, southern Slave, NT. | Canterra Minerals Corporation, Jan. 26, 2p. | Canada, Northwest Territories | News item - press release |
DC201507-1425 2015 | Canterra Minerals Corporation | Canterra provides exploration update on southern Slave properties, NWT. | Canterra Minerals Corporation, June 17, 2p. | Canada, Northwest Territories | News item - press release |
DC201508-1426 2015 | Canterra Minerals Corporation | Canterra announces $ 1 million financing 0.06 cts and flow through unit @ 0.08cts | Canterra Minerals Corporation, July 8, 1p. | Canada, Northwest Territories, Alberta | News item - press release |
DC201510-2336 2015 | Canterra Minerals Corporation | Canterra commences exploration program on South Slave properties, NT. | Canterra Minerals Corporation, Sept. 3, 1p. | Canada, Northwest Territories | News item - press release |
DC201512-2420 2015 | Canterra Minerals Corporation | Canterra completes exploration program, appoints new director and extends financing. Hilltop property Great Slave area | Canterra Minerals Corporation, Nov. 17, 1p. | Canada, Northwest Territories | News item - press release |
DS201502-0048 2015 | Cathles, L.M. | Future Rx: optimism, preparation, acceptance of risk. | In: Ore deposits of an evolving Earth, Geological Society of London,, Special Publication no. 393, pp. 303-324. | Global | Economics |
DS201502-0049 2015 | Cawood, P., Hawkesworth, C.J. | Temporal relations between mineral deposits and global tectonic cycles. | In: Ore deposits of an evolving Earth, Geological Society of London,, Special Publication no. 393, pp. 9-21. | Global | Tectonics |
| Abstract: Mineral deposits are heterogeneously distributed in both space and time, with variations reflecting tectonic setting, evolving environmental conditions, as in the atmosphere and hydrosphere, and secular changes in the Earth’s thermal history. The distribution of deposit types whose settings are tied to plate margin processes (e.g. orogenic gold, volcanic-hosted massive sulphide, Mississippi valley type Pb-Zn deposits) correlates well with the supercontinent cycle, whereas deposits related to intra-cratonic settings and mantle-driven igneous events, such as Ni-Cu-PGE deposits, lack a clear association. The episodic distribution of deposits tied to the supercontinent cycle is accentuated by selective preservation and biasing of rock units and events during supercontinent assembly, a process that encases the deposit within the assembled supercontinent and isolates it from subsequent removal and recycling at plate margins. |
DS201509-0388 2015 | Cawthorn, R.G. | The geometry and emplacement of the Pilanesberg Complex, South Africa. | Geological Magazine, Vol. 152, 5, pp. 802-812. | Africa, South Africa | Alkalic |
| Abstract: The circular 625 km2 alkaline Pilanesberg Complex, South Africa, contains coeval eruptive and several distinctive intrusive syenitic and foyaitic components, concentrically arranged at the surface. However, owing to poor outcrop the relationships between the different intrusive rocks, and their shape in the third dimension cannot be convincingly determined in the field. The original interpretation was a laccolith, whereas later models suggested a funnel shape, and appealed to ring-dyke and cone-sheet emplacement mechanisms. However, the radial widths of these coarse-grained bodies are over 1 km and so cannot have been emplaced as ring dykes or cone sheets, which are usually quite thin and fine grained. Creating the space for emplacement and removal of pre-existing country rocks for each postulated subsequent intrusive event presents a major challenge to this latter hypothesis. Extensive previously published and new field relationships are re-evaluated here to suggest that the body is a gently inward-dipping sheet and that subsequent injections of magma merely pumped up an existing and evolving magma chamber rather than intruded into solid rocks. A Bouguer gravity anomaly model is presented that supports the concept of a shallow, flat-bottomed body rather than one that continues to significant depth. There are many analogies with the Kangerlussuaq Intrusion, Greenland. |
DS201512-1902 2015 | Cayer, E.M., Winterburn, P.A., Elliott, B. | Development of geochemical exploration technologies for the discovery of concealed kimberlites under glacial overburden, NWT. | 43rd Annual Yellowknife Geoscience Forum Abstracts, abstract p. 22. | Canada, Northwest Territories | Geochemistry |
| Abstract: Attention is being focused on the development of deep penetrating geochemical exploration methods as the discovery rate of world class deposits decreases. Diamondiferous kimberlites located in the Lac de Gras region of the Northwest Territories are one of the many deposit types in Canada covered by glacial overburden, and are therefore challenging to detect. This paper presents initial results from an investigation of the DO-18 kimberlite (Peregrine Diamonds), buried under 5-20m of glacial cover, to identify surface geochemical responses directly related to the buried kimberlite and differentiate between physical and chemical transport mechanisms. A detailed grid of 150 samples over an area of 0.5km2 sampled the oxidized upper B soil horizon in till above and off the DO-18 kimberlite into background. Regolith mapping was conducted and included surficial soil type and rock fragments, topographic variation and physical features, e.g. bogs, swamps, vegetation and glacial direction indicators. This allows an assessment of surface controls on the geochemistry, including the generation of false anomalies from chemical traps such as swamps. Multi-element geochemistry comprising 4-acid, Aqua-Regia and distilled water extraction coupled with ICP-MS was undertaken using commercial techniques to identify and differentiate between those elements migrating by chemical process from those migrating by physical transportation. Hydrocarbons were analysed using the SGH-technique (ActLabs) and the Gore-sorber technique (AGI) to characterize type and abundance of complex hydrocarbons above the kimberlite relative to the host granite gneiss. Preliminary results from the 4-acid digestion data show a clastic dispersion of Nb, Ni, Mg, Co, Cr and Cs from directly above the kimberlite to the edge of the sampling grid 500 metres northwest of the buried kimberlite. Surface material exhibits a strong control on geochemistry with trace elements being controlled by major elements (Al, Fe, Mn) found within each surface material type, and in some cases are heavily influenced by the presence of organic carbon. Evaluation of these relationships allows clarification of the natural background noise and enhancement of the geochemical responses and contrasts. |
DM201501-0467 2014 | CBC News | Work starts on winter road network in Ontario. Victor | Cbcnews.ca, Dec. 9, 1p. | Canada, Ontario | News item - ice roads |
DM201502-2464 2015 | CBC News | Taken alone, NWT exploration figures fail to impress. | Cbcnews.ca, Jan. 22, 1/2p. | Canada, Northwest Territories | News item - spending |
DM201503-0468 2015 | CBC News | Clock ticking on Ekati mine expansion: Dominion Diamond Corporation. Company says current timeline of environmental assessment could delay construction, prompt layoffs. | Cbcnews.ca, Jan. 25, 1p. | Canada, Northwest Territories | News item - Dominion |
DM201503-0469 2015 | CBC News | N.W.T. to study diamond mine ice road into all-season road. | Cbcnews.ca, Jan. 29, 1/4p. | Canada, Northwest Territories | News item - ice road |
DM201504-0470 2015 | CBC News | Snap Lake mine could close if dissolved solid limit not raised: De Beers. Company asking Mackenzie Valley Land and Water Board to nearly triple limit. | Cbcnews.ca, Mar. 13, 2p. | Canada, Northwest Territories | News item - De Beers |
DM201507-0473 2015 | CBC News | Yellowknives Dene lose Drybones Bay diamond exploration appeal. Federal court upholds Debogorski's proposal. ( took 4 years and will still be appealed by Dene) | Cbcnews.ca, June 26, 1p. | Canada, Northwest Territories | News item - Drybones Bay |
DM201507-0474 2015 | CBC News | 2nd De Beers Snap Lake dissolved solid limit increase OK'd by N.W.T. board. Mackenzie Valley Land and Water Board( 1,000 milligrams per litre for rest of mine's life.) | Cbcnews.ca, June 25, 1p. | Canada, Northwest Territories | News item - De Beers |
DM201508-0471 2015 | CBC News | Nunavut property owners owe nearly $ 3.3 million in tax arrears. Shear Minerals owes $ 1.5 in property tax arrears on its abandoned Jericho Diamond Mine. | Cbcnews.ca, July 8, 1/2p. | Canada, Nunavut | News item - Shear Minerals |
DM201508-0472 2015 | CBC News | Ekati mine expansion in NWT doesn’t need review: feds. Jay project. | Cbcnews.ca, July 22, 1/4p. | Canada, Northwest Territories | News item - Dominion |
DM201510-2002 2015 | CBC News | Snap Lake diamond mine's water licence change ok'd by N.W.T. minister. | CBCnews.ca , Sept. 17, 1p. | Canada, Northwest Territories | News item - De Beers |
DM201510-2003 2015 | CBC News | Diavik's mine's ability to recoup $ 159 million security at risk from Ekati expansion: Rio Tinto. Jay | CBCnews.ca , Sept. 2, 1p. | Canada, Northwest Territories | News item - Rio Tinto |
DM201511-2112 2015 | CBC News | Why De Beers makes diamonds it will never sell. ( lab synthetics) Element Six | CBC.ca, Oct. 8, 3p. | Technology | News item - De Beers |
DC201512-2421 2015 | Centaurus Diamond Technologies Inc. | Restarts final phase of R&D in revolutionary cultured diamond … Magnatek | Centaurus Diamond Technologies, Inc., Nov. 5, 1p. | Technology | News item - press release |
DS201504-0188 2015 | Cerantola, V., Walte, N.P., Rubie, D.C. | Deformation of a crystalline olivine aggregate containing two immiscible liquids: implications for early core-mantle differentiation. | Earth and Planetary Science Letters, Vol. 417, pp. 67-77. | Mantle | Core, mantle |
| Abstract: Deformation-assisted segregation of metallic and sulphidic liquid from a solid peridotitic matrix is a process that may contribute to the early differentiation of small planetesimals into a metallic core and a silicate mantle. Here we present results of an experimental study using a simplified system consisting of a polycrystalline Fo90-olivine matrix containing a small percentage of iron sulphide and a synthetic primitive MORB melt, in order to investigate whether the silicate melt enhances the interconnection and segregation of FeS liquid under deformation conditions at varying strain rates. The experiments have been performed at 2 GPa, 1450?°C and strain rates between 1×10?3 s?11×10?3 s?1 to 1×10?5 s?11×10?5 s?1. Our results show that the presence of silicate melt actually hinders the migration and segregation of sulphide liquid by reducing its interconnectivity. At low to moderate strain rates the sulphide liquid pockets preserved a roundish shape, showing the liquid behavior is governed mainly by surface tension rather than by differential stress. Even at the highest strain rates, insignificant FeS segregation and interconnection were observed. On the other hand the basaltic melt was very mobile during deformation, accommodating part of the strain, which led to its segregation from the matrix at high bulk strains leaving the sulphide liquid stranded in the olivine matrix. Hence, we conclude that deformation-induced percolation of sulphide liquid does not contribute to the formation of planetary cores after the silicate solidus is overstepped. A possible early deformation enhanced core-mantle differentiation after overstepping the Fe-S solidus is not possible between the initial formation of silicate melt and the formation of a widespread magma ocean. |
DS201510-1761 2014 | Chakhmouradian, A.R., Cooper, M.A., Ball, N., Reguir, E.P., Medici, L., Abdu, Y., Antonov, A.A. | Vladykinite, Na3Sr4(Fe2+Fe3+)Si8024: a new complex sheet silicate from peralkaline rocks of the Murun Complex, eastern Siberia, Russia. | Deep-seated magmatism, its sources and plumes, Proceedings of XIII International Workshop held 2014., Vol. 2014, pp. 5-21. | Russia, Siberia | Deposit - Murun |
| Abstract: Vladykinite, ideally Na3Sr4(Fe2+Fe3+)Si8O24, is a new complex sheet silicate occurring as abundant prismatic crystals in a dike of coarse-grained peralkaline feldspathoid syenite in the north-central part of the Murun complex in eastern Siberia, Russia (Lat. 58° 22? 48? N; Long. 119° 03? 44? E). The new mineral is an early magmatic phase associated with aegirine, potassium feldspar, eudialyte, lamprophyllite, and nepheline; strontianite (as pseudomorphs after vladykinite) and K-rich vishnevite are found in the same assemblage, but represent products of late hydrothermal reworking. Vladykinite is brittle, has a Mohs hardness of 5, and distinct cleavage on {100}. In thin section, it is colorless, biaxial negative [a = 1.624(2), b = 1.652(2), g = 1.657(2), 2Vmeas = 44(1)°, 2Vcalc = 45(1)°] and shows an optic orientation consistent with its structural characteristics (X^a = 5.1° in b obtuse, Z^c = 4.7° in b acute, Y = b). The Raman spectrum of vladykinite consists of the following vibration modes (listed in order of decreasing intensity): 401, 203, 465, 991, 968, 915, 348, 167, 129, 264, 1039, and 681 cm–1; O-H signals were not detected. The Mössbauer spectrum indicates that both Fe2+ and Fe3+ are present in the mineral (Fe3+/FeS = 0.47), and that both cations occur in a tetrahedral coordination. The mean chemical composition of vladykinite (acquired by wavelength-dispersive X?ray spectrometry and laser-ablation inductively-coupled-plasma mass-spectrometry), with FeS recast into Fe2+ and Fe3+ in accord with the Mössbauer data, gives the following empirical formula calculated to 24 O atoms: (Na2.45Ca0.56)S3.01(Sr3.81 K0.04Ba0.02La0.02Ce0.01)S3.90(Fe2+0.75Fe3+0.66Mn0.26Zn0.16Al0.12Mg0.05Ti0.01)S2.01(Si7.81Al0.19)S8.00O24. The mineral is monoclinic, space group P21/c, a = 5.21381(13), b = 7.9143(2), c = 26.0888(7) Å, b = 90.3556(7)°, V = 1076.50(5) Å3, Z = 2. The ten strongest lines in the powder X?ray diffraction pattern are [dobs in Å (I) (hkl)]: 2.957 (100) (123, 123); 2.826 (100) (117, 117); 3.612 (58) (114, 114); 3.146 (37) (120); 2.470 (32) (210, 01.10); 4.290 (30) (111, 111); 3.339 (30) (106, 115, 106); 2.604 (28) (200); 2.437 (25) (034); 1.785 (25) (21.10, 234). The structure of vladykinite, refined by single-crystal techniques on the basis of 3032 reflections with Fo > 4sFo to R1 = 1.6%, consists of tetrahedral sheets parallel to (100) and consisting of (Si8O24)16– units incorporating four-membered silicate rings and joined into five- and eight-membered rings by sharing vertices with larger tetrahedra hosting Fe2+, Fe3+, Mn, Zn, Al, Mg, and Ti. Larger cations (predominantly Na, Sr, and Ca) are accommodated in octahedral and square-antiprismatic interlayer sites sandwiched between the tetrahedral sheets. Structural relations between vladykinite and other sheet silicates incorporating four-, five-, and eight-membered rings are discussed. The name vladykinite is in honor of Nikolay V. Vladykin (Vinogradov Institute of Geochemistry, Russia), in recognition of his contribution to the study of alkaline rocks. Holotype and co-type specimens of the mineral were deposited in the Robert B. Ferguson Museum of Mineralogy in Winnipeg, Canada. |
DS201512-1903 2015 | Chakhmouradian, A.R., Cooper, M.A., Medici, L., Abdu, Y.A., Shelukhina, Y.S. | Anzaite-(Ce), a new rare earth mineral and structure type from the AfrikAnd a silicocarbonatite, Kola Peninsula. | Mineralogical Magazine, Vol. 79, 5, pp. 1231-1244. | Russia | Carbonatite |
| Abstract: Anzaite-(Ce), ideally Formula Fe2+Ti6O18(OH)2, is a new, structurally complex mineral occurring as scarce minute crystals in hydrothermally altered silicocarbonatites in the Afrikanda alkali-ultramafic complex of the Kola Peninsula, Russia. The mineral is a late hydrothermal phase associated with titanite, hibschite, clinochlore and calcite replacing the primary magmatic paragenesis. The rare-earth elements (REE) (dominated by Ce), Ti and Fe incorporated in anzaite-(Ce) were derived from primary Ti oxides abundant in the host rock. Anzaite-(Ce) is brittle and lacks cleavage; the density calculated on the basis of structural data is 5.054(6) g cm?3. The mineral is opaque and grey with a bluish hue in reflected light; its reflectance values range from 15-16% at 440 nm to 13-14% at 700 nm. Its infrared spectrum shows a prominent absorption band at 3475 cm?1 indicative of OH? groups. The average chemical composition of anzaite-(Ce) gives the following empirical formula calculated on the basis of 18 oxygen atoms and two OH? groups: (Ce2.18Nd0.85La0.41Pr0.26Sm0.08Ca0.36Th0.01)?4.15Fe0.97(Ti5.68Nb0.22Si0.04)?5.94O18(OH)2. The mineral is monoclinic, space group C2/m, a = 5.290(2), b = 14.575(6), c = 5.234(2) Å, ? = 97.233(7)°, V = 400.4(5) Å3, Z = 1. The ten strongest lines in the X-ray micro-diffraction pattern are [dobs in Å (I) hkl]: 2.596 (100) 002; 1.935 (18) 170; 1.506 (14) 133; 1.286 (13) 1.11.0; 2.046 (12) 2?41; 1.730 (12) 003; 1.272 (12) 0.10.2; 3.814 (11) 1?11; 2.206 (9) 061; 1.518 (9) 172. The structure of anzaite-(Ce), refined by single-crystal techniques to R1 = 2.1%, consists of alternating layers of type 1, populated by REE (+ minor Ca) in a square antiprismatic coordination and octahedrally coordinated Fe2+, and type 2, built of five-coordinate and octahedral Ti, stacked parallel to (001). This atomic arrangement is complicated by significant disorder affecting the Fe2+, five-coordinate Ti and two of the four anion sites. The order-disorder pattern is such that only one half of these positions in total occupy any given (010) plane, and the disordered (010) planes are separated by ordered domains comprising REE, octahedral Ti and two anion sites occupied by O2?. Structural and stoichiometric relations between anzaite-(Ce) and other REE-Ti (±Nb, Ta) oxides are discussed. The name anzaite-(Ce) is in honour of Anatoly N. Zaitsev of St Petersburg State University (Russia) and The Natural History Museum (UK), in recognition of his contribution to the study of carbonatites and REE minerals. The modifier reflects the prevalence of Ce over other REE in the composition of the new mineral. |
DS201508-0344 2015 | Chakhmouradian, A.R., Reguir, E.P., Coueslan, C., Yang, P. | Calcite and dolomite in intrusive carbonatites. II Trace element variations. | Mineralogy and Petrology, in press available 17p. | Global | Carbonatite |
| Abstract: The composition of calcite and dolomite from several carbonatite complexes (including a large set of petrographically diverse samples from the Aley complex in Canada) was studied by electron-microprobe analysis and laser-ablation inductively-coupled-plasma mass-spectrometry to identify the extent of substitution of rare-earth and other trace elements in these minerals and the effects of different igneous and postmagmatic processes on their composition. Analysis of the newly acquired and published data shows that the contents of rare-earth elements (REE) and certain REE ratios in magmatic calcite and dolomite are controlled by crystal fractionation of fluorapatite, monazite and, possibly, other minerals. Enrichment in REE observed in some samples (up to ~2000 ppm in calcite) cannot be accounted for by coupled substitutions involving Na, P or As. At Aley, the REE abundances and chondrite-normalized (La/Yb)cn ratios in carbonates decrease with progressive fractionation. Sequestration of heavy REE from carbonatitic magma by calcic garnet may be responsible for a steeply sloping "exponential" pattern and lowered Ce/Ce* ratios of calcite from Magnet Cove (USA) and other localities. Alternatively, the low levels of Ce and Mn in these samples could result from preferential removal of these elements by Ce4+- and Mn3+-bearing minerals (such as cerianite and spinels) at increasing f(O2) in the magma. The distribution of large-ion lithophile elements (LILE = Sr, Ba and Pb) in rock-forming carbonates also shows trends indicative of crystal fractionation effects (e.g., concomitant depletion in Ba + Pb at Aley, or Sr + Ba at Kerimasi), although the phases responsible for these variations cannot be identified unambiguously at present. Overall, element ratios sensitive to the redox state of the magma and its complexing characteristics (Eu/Eu*, Ce/Ce* and Y/Ho) are least variable and in both primary calcite and dolomite, approach the average chondritic values. In consanguineous rocks, calcite invariably has higher REE and LILE levels than dolomite. Hydrothermal reworking of carbonatites does not produce a unique geochemical fingerprint, leading instead to a variety of evolutionary trends that range from light-REE and LILE enrichment (Turiy Mys, Russia) to heavy-REE enrichment and LILE depletion (Bear Lodge, USA). These differences clearly attest to variations in the chemistry of carbonatitic fluids and, consequently, their ability to mobilize specific trace elements from earlier-crystallized minerals. An important telltale indicator of hydrothermal reworking is deviation from the primary, chondrite-like REE ratios (in particular, Y/Ho and Eu/Eu*), accompanied by a variety of other compositional changes depending on the redox state of the fluid (e.g., depletion of carbonates in Mn owing to its oxidation and sequestration by secondary oxides). The effect of supergene processes was studied on a single sample from Bear Lodge, which shows extreme depletion in Mn and Ce (both due to oxidation), coupled with enrichment in Pb and U, possibly reflecting an increased availability of Pb2+ and (UO2)2+ species in the system. On the basis of these findings, several avenues for future research can be outlined: (1) structural mechanisms of REE uptake by carbonates; (2) partitioning of REE and LILE between cogenetic calcite and dolomite; (3) the effects of fluorapatite, phlogopite and pyrochlore fractionation on the LILE budget of magmatic carbonates; (4) the cause(s) of coupled Mn-Ce depletion in some primary calcite; and (5) relations between fluid chemistry and compositional changes in hydrothermal carbonates. |
DS201508-0345 2015 | Chakhmouradian, A.R., Reguir, E.P., Zaitsev, A.N. | Calcite and dolomite in intrusive carbonatites. I Textural variastions. | Mineralogy and Petrology, in press available 28p. | Global | Carbonatite |
| Abstract: Carbonatites are nominally igneous rocks, whose evolution commonly involves also a variety of postmagmatic processes, including exsolution, subsolidus re-equilibration of igneous mineral assemblages with fluids of different provenance, hydrothermal crystallization, recrystallization and tectonic mobilization. Petrogenetic interpretation of carbonatites and assessment of their mineral potential are impossible without understanding the textural and compositional effects of both magmatic and postmagmatic processes on the principal constituents of these rocks. In the present work, we describe the major (micro)textural characteristics of carbonatitic calcite and dolomite in the context of magma evolution, fluid-rock interaction, or deformation, and provide information on the compositional variation of these minerals and its relation to specific evolutionary processes. |
DS201508-0346 2015 | Chalapathi Rao, N.V., Atiullah, Kumar, A., Sahoo, S., Nanda, P., Chahong, N., Lehmann, B., Rao, K.V.S. | Petrogenesis of Mesoproterozoic lamproite dykes from the Garledinne (Banganapalle) cluster, south western Cuddapah Basin, southern India. | Mineralogy and Petrology, in press available 22p. | India | Lamproite |
| Abstract: We report mineral chemistry and whole-rock major and trace-element geochemistry for a recent find of Mesoproterozoic (~1.4 Ga) lamproites from the Garledinne (Banganapalle) cluster, south-western part of the Paleo-Mesoproterozoic Cuddapah Basin, southern India. The Garledinne lamproites occur as WNW-ESE-trending dykes that have undergone varying degree of pervasive silicification and carbonate alteration. Nevertheless, their overall texture and relict mineralogy remain intact and provide important insights into the nature of their magmas. The lamproite dykes have porphyritic to weakly porphyritic textures comprising pseudomorphed olivine macrocrysts and microphenocrysts, titanian phlogopite microphenocrysts, spinel having a compositional range from chromite to rarely magnesiochromite, Sr-rich apatite and niobian rutile. The Garledinne and other Cuddapah Basin lamproites (Chelima and Zangamarajupalle) collectively lack sanidine, clinopyroxene, potassic richterite, and titanite and are thus mineralogically distinct from the nearby Mesoproterozoic lamproites (Krishna and Ramadugu) in the Eastern Dharwar Craton, southern India. The strong correlation between various major and trace elements coupled with high abundances of incompatible and compatible trace elements imply that alteration and crustal contamination have had a limited effect on the whole-rock geochemistry (apart from K2O and CaO) of the Garledinne lamproites and that olivine fractionation played an important role in their evolution. The Garledinne lamproites represent small-degree partial melts derived from a refractory (previously melt extracted) peridotitic mantle source that was subsequently metasomatised (enriched) by carbonate-rich fluids/melts within the garnet stability field. The involvement of multiple reservoirs (sub-continental lithospheric mantle and asthenosphere) has been inferred in their genesis. The emplacement of the Garledinne lamproites is linked to extensional events, across the various Indian cratons, related to the break-up of the Proterozoic supercontinent of Columbia. |
DS201509-0389 2015 | Chalapathi Rao, N.V., Dongre, A., Wu, F-Y., Lehmann, B. | A Late Cretaceous ( ca.90Ma) kimberlite event in southern India: implication for sub-continental lithospheric mantle evolution and diamond exploration. Wajrakarur | Gondwana Research, in press available 12p. | India | Deposit - Timmasamudram |
DC201505-1428 2015 | Chalice Gold Mines Limited | Webb diamond project update. ( Meteoric Resources Limited press release) | Chalice Gold Mines Limited, Mar. 27, 1p. | Australia | News item - press release |
DS201506-0258 2015 | Chapin, M.,Pardieu, V., Lucas, A. | Mozambique: a ruby discovery for the 21st. Century. Montepuez | Gems & Gemology, Vol. 51, 1, pp. 44-54. | Africa, Mozambique | Deposit - ruby |
DS201504-0189 2015 | Chapman, J. | Why aren't all natural diamonds larger than 10 carats - they've had millions of years to grow. | Vancouver Kimberlite Cluster, Mar. 17, 1p. Abstract | Technology | Diamond morphology |
DS201504-0190 2015 | Chapman, J. | Chromism in pink diamonds. | The Australian Gemmologist, Vol. 25, 8, pp. 268-271. | Technology | Deposit - Argyle |
DS201511-1828 2004 | Chapman, J.G., Boxer, G.L. | Size distribution analyses for estimating grade and value. | Lithos, Vol. 76, pp. 369-375. Available pdf | Technology | Microdiamonds - responses |
| Abstract: Analysing the size frequency distributions (SFDs) of both micro diamonds and macro diamonds from primary deposits shows that the distributions are continuous across all sizes and that there are two regions of different character with a transition about 1-2 mm. Using log axes, the frequency curve is linear for the smaller sizes allowing slope and intercept parameters to be determined which are less ambiguous than stone counts and ratios of macro to micro populations that are generally reported. Modelling a diamond population that has undergone removal of a uniform thickness of the outer layer transforms a linear frequency curve into a quadratic form, which is also the form of the frequency curve for macro diamonds. Diamonds grown synthetically also display a linear distribution across a smaller fraction of their size distribution curve. |
DS201510-1762 2015 | 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. | Technology | X-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. |
DS201502-0050 2015 | Chen, M., Tian, W. | Surface and mantle expression of the Early Permian Tarim mantle plume. | Economic Geology Research Institute 2015, Vol. 17,, # 1147, 1p. Abstract | China | Peridotite, xenoliths |
| Abstract: The mantle process during the Early Permian Tarim plume event is revealed by flood basalt and mantle xenoliths. Permian Tarim flood basalts have typical two pulses' eruption. The first pulse of the Tarim flood basalt was erupted at 291-290Ma, characterized by OIB-like Zr/Nb (~5.83), Nb/La and Ce/Pb ratios, and PUM-like initial 187Os/188Os ratios (0.1308-0.1329). They're plotted along a 290±11Ma isochron, implying a pristine "plume mantle" source. The second pulse of the Tarim flood basalt was erupted at 283-281 Ma, with Zr/Nb (~13.6), Nb/La and Ce/Pb ratios similar or close to the lower crust and initial 187Os/188Os ratios (0.1743~19.6740) that deviated from the ~290 Ma isochron line, indicative of significant crustal assimilation. Mantle-derived peridotite and pyroxenite xenoliths hosted in Cenozoic alkali basalts (~20 Ma) are found in the Xikeer, western Tarim Block. Based on their petrographic and geochemical characteristics, peridotite xenoliths can be divided into three groups. Group 1 peridotites, with the presence of the high Mg-number of olivines (91-93) and spinel-pyroxenes clusters, experienced high-degree melt extraction (~17% fractional melting) from garnet- to spinel-stable field. Groups 2 and 3 peridotites, characterized by the clinopyroxenes with spoon-shaped and highly fractionated REE patterns respectively, underwent extensive silicate melt metasomatism at low melt/rock ratios (15) and that the host basanite is incapable of being the metasomatic agent. The Re-Os isotopic systematics of the Xikeer peridotites and pyroxenites yield an isochron of 290±11 Ma, virtually identical to the age of Tarim flood basalts. Their PUM-like Os initial ratios and convecting mantle-like É?Nd(t=290 Ma) strongly suggest that the Xikeer mantle xenoliths derive from the plume mantle. We propose that the Xikeer xenolith suite recorded mantle 'auto-refertilization' process, i.e., they may have been initially formed by melt extraction from the convecting mantle and, shortly after, was refertilized by plume melts during the Early Permian. |
DS201502-0051 2015 | Chen, T., Gwanmesia, G.D., Wang, X., Zou, Y., Liebermann, R.C., Michaut, C., Li, B. | Anomalous elastic properties of coesite at high pressure and implications for the upper mantle X-discontinuity. | Earth and Planetary Science Letters, Vol. 412, pp. 42-51. | Mantle | Coesite |
| Abstract: Compressional and shear wave velocities of coesite have been measured using ultrasonic interferometry in a multi-anvil apparatus up to 12.6 GPa at room temperature for the first time. While the P wave velocity increases continuously with pressure, the S wave exhibits an anomalous softening and the velocity decreases continuously with pressure. Finite strain analysis of the data yielded KS0=103.6(4) GPaKS0=103.6(4) GPa, G0=61.6(2) GPaG0=61.6(2) GPa and View the MathML sourceK0?=2.9(1), View the MathML sourceG0?=0.3(1) for the bulk and shear moduli and their pressure derivatives, respectively. The anomalous elastic behavior of coesite results in large velocity and impedance contrasts across the coesite–stishovite transition, reaching ?39% and ?48% for P and S wave velocity contrasts, and ?70% and 78% for P and S wave impedance contrasts, respectively, at pressure ?8 GPa, with P and S wave velocity perturbations showing no apparent dependence on depths (i.e., View the MathML sourcedln?V(PorS)/dh?0) within 8–12 GPa. These unusually large contrasts and depth independent characteristics render the transition between the two silica polymorphs one of the most plausible candidates for the cause of the seismically observed X-discontinuity. The current P and S wave velocity perturbation dependences on the SiO2 content, d(ln?VP)/d(SiO2)?0.43 (wt%)?1d(ln?VP)/d(SiO2)?0.43 (wt%)?1 and d(ln?VS)/d(SiO2)?0.60 (wt%)?1d(ln?VS)/d(SiO2)?0.60 (wt%)?1, can serve as a geophysical probe to track ancient subducted eclogite materials to gain insights on the geodynamics of the mantle. |
DS201512-1904 2015 | Chen, W., Leblanc, S.G., White, H.P., Milkovic, B., O'Keefe, H., Croft, B., Gunn, A., Boulanger, J. | Caribou relevant environmental changes around the Ekati diamond mine measured in 2015. | 43rd Annual Yellowknife Geoscience Forum Abstracts, abstract p. 24. | Canada, Northwest Territories | Deposit - Ekati |
| Abstract: How would a large open pit mine on caribou range (e.g., the Ekati Diamond Mine in the Bathurst caribou’s summer range) have influenced caribou? A traditional knowledge study on the cumulative impacts on the Bathurst caribou herd qualitatively described how mining activities might have influenced the herd (Mackenzie et al. 2013): caribou migration routes deflected away from the mines probably due to seeing mining activities or hearing the noises; and skinny caribou or abnormal smells and materials in caribou meat, liver, or the hide linings probably related to changes in caribou forage and quality of water and air. In other words, the potential influences of mining operations on caribou were most likely through altering what caribou can see, hear, smell (e.g., dusts and fine particle matter < 2.5 ?m (PM2.5) in the air, and from acidity in the soil), and taste (e.g., dust on foliage, vegetation composition change). Boulanger et al. (2012) estimated the size of a zone of influence (ZOI) of the Ekati-Diavik mining complex in the Bathurst caribou summer range, using caribou presence dataset. They also explored the mechanisms of ZOI using the spatial distribution of the total suspended particles, which was simulated with an atmospheric transport and dispersion model (Rescan, 2006). While these studies have added to our understanding of the possible impacts of mining operations on caribou, knowledge gaps remain. One outstanding gap is the lack of direct measurements about the caribou relevant environmental changes caused by mining operations. For example, exactly from how far away can caribou clearly see the vehicles driving on a mining road, or the buildings and the elevated waste piles in a camp? From how far away might caribou hear the noise caused by mining operations? To what spatial extent had the dusts and PM2.5 from mining operations influenced the tundra ecosystems? And how the dusts and PM2.5 from mining operations might have influenced caribou forage quality? Potentially these questions can be answered by in-situ measurements and satellite remote sensing. For example, studies have showed that it is possible to remotely sense PM2.5 distribution using twice-daily MODIS data at a spatial resolution of 1 km (Lyapustin et al., 2011; Chudnovsky et al., 2013; Hu et al., 2014). The objective of this study is thus to quantitatively measure these changes around the Ekati Diamond Mine, by means of in-situ surveys and satellite remote sensing. We conducted field surveys at more than 100 sites around the Ekati Diamond Mine during August 14-23, 2015, a collaborative effort of the NWT CIMP project entitled “Satellite Monitoring for Assessing Resource Development’s Impact on Bathurst Caribou (SMART)”, and the Dominion Diamond Ekati Corporation. In this presentation, we will report preliminary results and lessons learned from our first year’s study. |
DS201508-0347 2015 | Chepurov, A.A., Pokhilenko, N.P. | Experimental estimation of the kimberlite melt velosity. ( Nyurbinskaya mentioned) | Doklady Earth Sciences, Vol. 462, 2, pp. 592-595. | Technology | Petrology - geodynamic model |
DC201510-2337 2015 | CMKM Diamonds Inc. | CMKM defendants see Spooner plead guilty. | Stockwatch, Sept. 10, 2p. | United States, Nevada | News item - CMKM |
DM201508-0478 2015 | CNN | Park visitor unearths 8.52 carat diamond in Arkansas. Esperanza Diamond | CNN, June 27, 1p. | United States, Arkansas | News item - Crater of Diamonds |
DM201508-0479 2015 | CNN | Rains wash out gems, lives in Gujarat diamond district. | CNN, June 27, 1/2p. | India | News item - Gujarat |
DS201511-1829 2015 | Coblentz, D., Van Wijk, J., Richardson, R.M., Sandiford, M. | The upper mantle geoid: implications for continental structure and the intraplate stress field. | Geological Society of America Special Paper, No. 514, pp. SPE514-13. | Mantle | Geophysics - seismics |
| Abstract: We use the fact that geoid anomalies are directly related to the local dipole moment of the density-depth distribution to help constrain density variations within the lithosphere and the associated tectonic stresses. The main challenge with this approach is isolating the upper mantle geoid contribution from the full geoid (which is dominated by sources in the lower mantle). We address this issue by using a high-pass spherical harmonic filtering of the EGM2008-WGS84 geoid to produce an "upper mantle" geoid. The tectonic implications of the upper mantle are discussed in terms of plate tectonics and intraplate stresses. We find that globally there is about a 9 meter geoid step associated with the cooling oceanic lithosphere that imparts a net force of ~2.5x1012 N/m in the form of "ridge push" - a magnitude that is consistent with 1-d models based on first-order density profiles. Furthermore, we ind a consistent 6 meter geoid step across passive a continental margin which has the net effect of educing the compressive stresses in the continents due to the ridge force. Furthermore, we use the pper mantle geoid to reevaluate the tectonic reference state which previously studies estimated using n assumption of Airy-based isostasy. Our evaluation of the upper mantle geoid confirms the near quivalence of the gravitational potential energy of continental lithosphere with an elevation of about 750 meters and the mid-ocean ridges. This result substantiates early conclusions about the tectonic reference state and further supports the prediction that continental regions are expected to be in a slightly extensional state of stress. |
DS201503-0137 2015 | Cohen, R. | Missing link in metal physics explains Earth's magnetic field. | gl.ciw.edu, Jan. 28, 1p. | Technology | Magnetics |
DS201504-0191 2015 | Comin-Chiaramonti, P., Gomes, C.B., De Min, A., Ernesto, M., Gasparon, M. | Magmatism along the high Paraguay River at the border of Brazil and Paraguay: a review and new constraints on emplacement ages. | Journal of South American Earth Sciences, Vol. 58, March pp. 72-81. | South America, Paraguay, Brazil | Geochronology |
| Abstract: The magmatic rocks from Alto Paraguay (High Paraguay River extensional lineament), western Apa craton, mainly consist of several major circular alkaline complexes and some rhyolitic domes and ignimbrites. The former are characterized by intrusive Na-alkaline rock-types (nepheline syenites and syenites and effusive equivalents) topped by lava flows and ignimbrites. Two main evolved suites were defined using petrochemical and Sr- isotope data: an agpaitic suite in the north and a miaskitic suite in the south. The domes of subalkaline rhyolitic lavas and ignimbrites occur to the north of the alkaline complexes, along the Paraguay River, near the town of Fuerte Olimpo. The emplacement ages of the alkaline complexes were constrained using the K-Ar, Ar-Ar, Rb-Sr and Sm-Nd dating methods on whole rocks and/or mineral separates (amphibole, alkali feldspar and biotite). Ages are quite variable (Upper Permian to Middle Triassic), with average K-Ar and Ar-Ar ages of 248.8 ± 4.8 and 241.8 ± 1.1 Ma, respectively, and Rb-Sr and Sm-Nd age data giving best values from 248 ± 4 to 244 ± 27 Ma and from 256 ± 3 to 257 ± 3 Ma, respectively. In contrast, the Fuerte Olimpo volcanics show a Mesoproterozoic age (1.3 Ga, K-Ar and Ar-Ar radiometric methods; and 1.42 ± 0.24 to 1.30 ± 0.03 Ga, Rb-Sr and Sm-Nd methods, respectively). Rb-Sr systematics (87Sr/86Sr initial ratios ? 0.7038) highlight a relatively "primitive" character of the Na-alkaline magmatic source(s), in contrast with the "crustal" values (87Sr/86Sr initial ratio ? 0.7105) of the Fuerte Olimpo rhyolites. Thus, magmatism in the Alto Paraguay area is related to two extensional events: a younger event corresponding to the Permian-Triassic alkaline rocks, and an older event connected to the Precambrian volcanic acidic rocks. |
DC201505-1429 2015 | Commerce Resources Corporation | Commerce Resources completes 22 drill holes at the Ashram rare earth deposit. | Commerce Resources Corporation, Apr. 15, 2p. | Canada, Quebec | News item - press release |
DC201505-1430 2015 | Commerce Resources Corporation | Completes floatation pilot plant for Ashram rare earth deposit. | Commerce Resources Corporation, Apr. 20, 2p. | Canada, British Columbia | News item - press release |
DS201510-1763 2015 | Condie, B. | Scientists create record pressure in a lab - twice that of Earth's core. Osmium sample. | blog. cosmos magazine.com, Aug. 25, 1p. | Technology | Osmium |
DS201506-0259 2015 | Condie, K., Davaille, Aster | Upstairs - downstairs: supercontinents and large igneous provinces, are they related? | International Geology Review, Vol. 57, 11-12, pp. 1341-1348. | Mantle | Supercontinents |
| Abstract: There is a correlation of global large igneous province (LIP) events with zircon age peaks at 2700, 2500, 2100, 1900, 1750, 1100, and 600 and also probably at 3450, 3000, 2000, and 300?Ma. Power spectral analyses of LIP event distributions suggest important periodicities at 250, 150, 100, 50, and 25?million years with weaker periodicities at 70-80, 45, and 18-20?Ma. The 25?million year periodicity is important only in the last 300?million years. Some LIP events are associated with granite-forming (zircon-producing) events and others are not, and LIP events at 1900 and 600?Ma correlate with peaks in craton collision frequency. LIP age peaks are associated with supercontinent rifting or breakup, but not dispersal, at 2450-2400, 2200, 1380, 1280, 800-750, and ?200?Ma, and with supercontinent assembly at 1750 and 600?Ma. LIP peaks at 2700 and 2500?Ma and the valley between these peaks span the time of Neoarchaean supercraton assemblies. These observations are consistent with plume generation in the deep mantle operating independently of the supercontinent cycle and being controlled by lower-mantle and core-mantle boundary thermochemical dynamics. Two processes whereby plumes can impact continental assembly and breakup are (1) plumes may rise beneath supercontinents and initiate supercontinent breakup, and (2) plume ascent may increase the frequency of craton collisions and the rate of crustal growth by accelerating subduction. |
DS201509-0390 2015 | Cooper, C.M. | Puzzling the pieces - supercontinent at depth. | Geology, Vol. 43, 9, pp. 847-848. | Global | Plate reconstructions |
| Abstract: Alfred Wegener famously argued that the seemingly puzzle piece–like fit of the Atlantic coastlines was not a mere coincidence, but rather one line of evidence proving that the continents were once arranged as a single, coherent supercontinent (Wegener, 1912,1920). This puzzle piece observation eventually launched a revolution that changed our understanding of the Earth from its deep interior to evolutionary processes. Often, however, we think of the supercontinent puzzle in a two-dimensional sense, neglecting to include or consider how variations of the thickness of the puzzle pieces might also be at play. How do the puzzle pieces fit together at depth, and is there more to learn by including lithospheric thickness in our plate reconstructions? Would thinking three-dimensionally in our plate reconstructions help resolve some of the outstanding questions about supercontinents, continental deformation, and the lithosphere in general? This is the motivation of new research by McKenzie et al. (2015, p. 783 in this issue of Geology). |
DS201512-1905 2015 | Cordier, C., Sauzeat, L., Arndt, N.T., Boullier, A-M., Batanova, V., Barou, F. | Metasomatism of the lithospheric mantle immediately precedes kimberlite eruption: new evidence from olivine composition and microstructures. | Journal of Petrology, Vol. 56, 9, pp. 1775-1796. | Technology | Olivine, metasomatism |
| Abstract: Most kimberlites contain abundant dunitic nodules. These are centimetre-sized, rounded and multi-grained assemblages of xenocrystic olivine with a wide range of compositions (Fo83 to Fo94). The absence of orthopyroxene and other mantle minerals and the range of olivine compositions have been attributed to reaction between mantle peridotite and (proto)kimberlitic fluid or melt, but the timing of the reaction is a subject of debate. In a kimberlite from the Kangamiut region of Greenland, nodule cores are surrounded by fine-grained outer margins with near-constant Fo contents (~Fo88) but highly variable minor element contents (e.g. 500-2500 ppm Ni). These margins crystallized from the kimberlite melt and we show that their compositions can be explained by crystallization of olivine alone, if a high partition coefficient for Ni between melt and olivine (DNi > 20) is assumed. Orthopyroxene assimilation is not required, removing the constraint that its dissolution occurred during ascent of the kimberlite magma. Within some nodules, in addition to the usual core-to-margin gradients, we observe asymmetric compositional changes (variable Fo but near-constant minor element contents) across mobile grain boundaries. These changes document fluid percolation at the grain scale that occurred during dynamic recrystallization in the deforming lithospheric mantle. We note that chemical gradients associated with mobile grain boundaries are observed in olivines that cover the entire compositional range of the nodules, and propose that fluid-assisted dynamic recrystallization took place in dunite that was already compositionally heterogeneous. Reaction between peridotite and protokimberlitic melt or fluid and dissolution of orthopyroxene thus occurred within the lithospheric mantle, immediately (a few days) prior to the ascent of the kimberlite melt and the entrainment of the dunite nodules. We propose that the grain boundary zones probably mimic, at a fine scale, the fluid-peridotite interaction that caused, at a larger scale, orthopyroxene dissolution and formation of compositionally diverse olivine in kimberlites. |
DS201509-0391 2015 | Cornah, A., Machaka, E. | Integration of imprecise and biased dat a into mineral resource estimates. | South African Institute of Mining and Metallurgy, Vol. 115, June pp. 523-531. | Global | Resource estimation, kriging not specific to diamonds |
| Abstract: Mineral resources are typically informed by multiple data sources of varying reliability throughout a mining project life cycle. Abundant data which are imprecise or biased or both (‘secondary data’) are often excluded from mineral resource estimations (the ‘base case’) under an intuitive, but usually untested, assumption that this data may reduce the estimation precision, bias the estimate, or both. This paper demonstrates that the assumption is often wasteful and realized only if the secondary data are naïvely integrated into the estimation. A number of specialized geostatistical tools are available to extract maximum value from secondary information which are imprecise or biased or both; this paper evaluates cokriging (CK), multicollocated cokriging (MCCK), and ordinary kriging with variance of measurement error (OKVME). Where abundant imprecise but unbiased secondary data are available, integration using OKVME is recommended. This re-appropriates kriging weights from less precise to more precise data locations, improving the estimation precision compared to the base case and to Ordinary Kriging (OK) of a pooled data-set. If abundant secondary data are biased and imprecise, integration through CK is recommended as the biased data are zero-sum weighted. CK consequently provides an unbiased estimate with some improvement in estimation precision compared to the base case. |
DS201512-1906 2015 | Counts, B., Power, M. | Proxima Diamonds Corp.: exploring for diamonds in the fertile Slave craton. | 43rd Annual Yellowknife Geoscience Forum Abstracts, abstract p. 33. | Canada, Northwest Territories | Prospect - Sancy |
| Abstract: Proxima Diamonds Corp. is a private Canadian diamond exploration company exploring diamond targets in the heart of the diamond producing region of the Slave Geological Province. The company holds 17 target-rich properties that were selected based on a review of publicly available data, a proprietary kimberlite indicator mineral sample database and a wealth of experience exploring for diamonds in Canada's north. Focused kimberlite indicator mineral (KIM) sampling conducted by Proxima in 2014 identified a potential source area on the Sancy Property, located near the northern boundary of the Ekati Diamond Mine. Follow-up ground geophysical surveys completed over the area in spring 2015 have returned compelling results. Ground gravity, total magnetic field and capacitively coupled resistivity surveys identified a large, new target approximately 300 m from the diamondiferous T-10 kimberlite pipe. On this and other Proxima properties, focused KIM till sampling is defining likely source areas which will be surveyed with ground geophysical methods this winter. |
DS201503-0138 2014 | Cowing, M.D. | Objective diamond clarity grading. | The Journal of Gemmology, Vol. 34, 4, pp. 316-332. | Technology | Methodology and consistency |
DS201503-0139 2015 | Cowing, M.D. | Grading diamond clarity objectively. | Book - self published, michaelgem @gmail.com, Book available | Technology | Diamond grading |
DS201506-0260 2015 | Crater of Diamonds State Park | Park visitor from Arkansas finds 3.69 carat white, teardrop-shaped diamond yesterday ( April 23) at Arkansas Crater of Diamonds State Park. Hallelujah name | Crater of Diamonds State Park, Apr. 23, 2p. | United States, Arkansas | Crater of Diamonds |
DM201501-0480 2014 | Creamers Mining Weekly | Rio Tinto on path to sustainable increased shareholder returns. | Creamers Mining Weekly, Dec. 4, 1/4p. | Global | News item - Rio Tinto |
DM201501-0481 2014 | Creamers Mining Weekly | Rio Tinto diamond bet adds sparkle to junior miner's prospects. | Creamers Mining Weekly, Dec. 4, 1/4p. | Canada | News item - Rio Tinto |
DM201501-0482 2014 | Creamers Mining Weekly | Diamonds look to set to do well in 2015 - Investec. | Creamers Mining Weekly, Dec. 5, 1/4p. | Global | News item - prices |
DM201501-0483 2014 | Creamers Mining Weekly | First diamonds exported from Baoule trial mining. | Creamers Mining Weekly, Dec. 5, 1/4p. | Africa, Guinea | News item - Stellar |
DM201501-0484 2014 | Creamers Mining Weekly | Strike ends at DiamondCorp's Lace mine, workers to return on Monday. | Creamers Mining Weekly, Dec. 5, 1/4p. | Africa, South Africa | News item - DiamondCorp |
DM201501-0485 2014 | Creamers Mining Weekly | Paragon raises Lb257,000 | Creamers Mining Weekly, Dec. 5, 1/4p. | Africa, Lesotho | News item - Paragon |
DM201501-0486 2014 | Creamers Mining Weekly | Stellar secures sufficient funds for working needs until first diamond sales. | Creamers Mining Weekly, Dec. 11, 1/4p. | Africa, Guinea | News item - Stellar |
DM201501-0487 2014 | Creamers Mining Weekly | Despite sagging grades, prices, Rockwell Diamonds reports record Q3 revenue. | Creamers Mining Weekly, Dec. 16, 1/4p. | Africa, South Africa | News item - Rockwell |
DM201502-0488 2015 | Creamers Mining Weekly | De Beers launches hub for entrepreneurs in Cape Town. De Beers Marine Zimele Business Hub. | Creamers Mining Weekly, Jan. 8, 1/4p. | Africa, South Africa | News item - DBCM |
DM201502-0489 2015 | Creamers Mining Weekly | Rio Tinto to invest $ 500 m in diamond project in India. | Creamers Mining Weekly, Jan. 12, 1/4p. | India, Madhya Pradesh | News item - Rio Tinto |
DM201502-0490 2015 | Creamers Mining Weekly | Rockwell boosts carat sales as recovery of large diamonds falters. | Creamers Mining Weekly, Jan. 13, 1/4p. | Africa, South Africa | News item - Rockwell |
DM201502-0491 2015 | Creamers Mining Weekly | The low oil price is expected to benefit the diamond business. De Beers CEO Phillippe Mellier. | Creamers Mining Weekly, Jan. 21, 1/4p. | Global | News item - De Beers |
DM201503-0492 2015 | Creamers Mining Weekly | Gem Diamonds warns of possible price softening in early 2015. Elphick | Creamers Mining Weekly, Jan. 27, 2p. | Africa, Botswana | News item - Gem Diamonds |
DM201503-0493 2015 | Creamers Mining Weekly | Diamond demand on the rise. | Creamers Mining Weekly, Feb. 10, 1p. | Global | News item - demand |
DM201503-0494 2015 | Creamers Mining Weekly | Coloured gemstones coming into their own after being outshone by diamonds for decades. | Creamers Mining Weekly, Feb 12, 1/4p. | Global | News item - gemstones |
DM201503-0495 2015 | Creamers Mining Weekly | Construction of De Beers Letlhakane tailings treatment plant. | Creamers Mining Weekly, Feb. 20, 1/2p. | Africa, Botswana | News item - De Beers |
DM201503-0496 2015 | Creamers Mining Weekly | Botswana Diamonds with partner Alrosa focusing on Orapa area. Siesko and Future | Creamers Mining Weekly, Feb. 20, 1/2p. | Africa, Botswana | News item - Botswana Diamonds, Alrosa |
DM201503-0497 2015 | Creamers Mining Weekly | Lucara Diamond Corp declares special dividend on strong 2014 performance. Karowe | Creamers Mining Weekly, Feb. 22, 1/4p. | Africa, Botswana | News item - Lucara |
DM201503-2465 2015 | Creamers Mining Weekly | Mountain Province Diamonds starts C$95 m rights offering to fund cost overrun facility. | Creamers Mining Weekly, Feb.22, 1/4p. | Canada, Northwest Territories | News item - Mountain Province |
DM201504-0498 2015 | Creamers Mining Weekly | Aim listed diamond explorer Botswana Diamonds has shifted its 2015 focus to three licence areas covering more than 1000 km2 in the diamond province of Orapa, Botswana. Gope | Creamers Mining Weekly, Feb. 20, 2p. | Africa, Botswana | News item - Botswana Diamonds |
DM201504-0499 2015 | Creamers Mining Weekly | Diamcor earnings drop 36%y/y. Krone-Endora | Creamers Mining Weekly, Feb. 27, 1/4p. | Africa, South Africa | News item - Diamcor |
DM201504-0500 2015 | Creamers Mining Weekly | Construction on Letlhakane tailings expansion to start soon. | Creamers Mining Weekly, Feb 25, 1p. | Africa, Botswana | News item - Debswana |
DM201504-0501 2015 | Creamers Mining Weekly | Rio Tinto discloses tax payments to governments. | Creamers Mining Weekly, Mar. 18, 1/4p. | Global | News item - Rio Tinto |
DM201504-0502 2015 | Creamers Mining Weekly | Early signs of another good year for diamond jewellery - De Beers. | Creamers Mining Weekly, Mar. 20, 1/4p. | Global | News item - De Beers |
DM201504-0503 2015 | Creamers Mining Weekly | Global diamond jewellery demand hits record $ 81 bln. | Creamers Mining Weekly, Mar. 20, 1/4p. | Global | News item - De Beers |
DM201504-0504 2015 | Creamers Mining Weekly | SA junior in partnership to reopen Ghana diamond mine. Limoz Resources and Great Consolidated Diamond Ghana Limited. Akwatia | Creamers Mining Weekly, Mar. 20, 1p. | Africa, Ghana | News item - Limoz |
DM201504-0505 2015 | Creamers Mining Weekly | Faltering Mbada resorts to digging conglomerate diamonds. Marange | Creamers Mining Weekly, Mar. 19, 1/2p. | Africa, Zimbabwe | News item - Mbada |
DM201504-0506 2015 | Creamers Mining Weekly | New mining legislation to empower Indian provinces ( have to adhere to federal guidelines). | Creamers Mining Weekly, Mar. 25, 1/4p. | India | News item - legal |
DM201505-0507 2015 | Creamers Mining Weekly | De Beers starts three year global sightholder sales contracts. | Creamers Mining Weekly, Mar. 31, 1/4p. | Global | News item - De Beers |
DM201505-0508 2015 | Creamers Mining Weekly | Norton Rose Fulbright advises on $ 370 m financing of world's largest new diamond project. Gahcho Kue | Creamers Mining Weekly, Apr. 10, 1/4p. | Canada, Northwest Territories | News item - Mountain Province |
DM201505-0509 2015 | Creamers Mining Weekly | Debswana to cap output due to slow demand. | Creamers Mining Weekly, Apr. 10, 1/4p. | Africa, Botswana | News item - Debswana |
DM201505-0510 2015 | Creamers Mining Weekly | Flawless 100 carat diamond sells for $ 22.1 million at N.Y. auction. | Creamers Mining Weekly, Apr. 22, 1/4p. | Africa, South Africa | News item - diamond notable |
DM201505-0511 2015 | Creamers Mining Weekly | Rio Tinto's Zimbabwe diamond production falls 42% in Q1. Murowa | Creamers Mining Weekly, Apr. 21, 1/4p. | Africa, Zimbabwe | News item - Rio Tinto |
DM201506-0512 2015 | Creamers Mining Weekly | Zimbabwe suspends tax on diamond sales - letter to IMF. | Creamers Mining Weekly, Apr. 30, 1/4p. | Africa, Zimbabwe | News item - legal |
DM201506-0513 2015 | Creamers Mining Weekly | World Bourses prepare to confront diamond troubles at global gathering. | Creamers Mining Weekly, Apr. 30, 1/4p. | Global | News item - Bourses |
DM201506-0514 2015 | Creamers Mining Weekly | Lace mine on target for mid-year start up. | Creamers Mining Weekly, Apr. 30, 1/4p. | Africa, South Africa | News item - DiamondCorp |
DM201506-0515 2015 | Creamers Mining Weekly | BlueRock completes upgrade of Kareevlei plant, resumes commercial mining. | BlueRock Diamonds Plc., May 19, 1/4p. | Africa, South Africa | News item - BlueRock |
DM201506-0516 2015 | Creamers Mining Weekly | New mineral development strategy seeks to maintain Ontario's pole position. | Creamers Mining Weekly, May 20, 1p. | Canada, Ontario | News item - legal |
DM201506-0517 2015 | Creamers Mining Weekly | Trans Hex readies or hefty FY earninsg jump. | Creamers Mining Weekly, May 25, 1/4p. | Africa, South Africa | News item - Trans Hex |
DM201506-0518 2015 | Creamers Mining Weekly | Mining to kick off at Lace mine ahead of schedule in H2. | Creamers Mining Weekly, May 26, 1/4p. | Africa, South Africa | News item - DiamondCorp |
DM201507-0519 2015 | Creamers Mining Weekly | Lucapa to sign earthmoving deal, lists on Frankfurt Stock Exchange 28 May. Lulo | Creamers Mining Weekly, May 28, 1p. | Africa, Angola | News item - Lucapa |
DM201507-0520 2015 | Creamers Mining Weekly | India makes provisions for composite mining licences. | Creamers Mining Weekly, June 3, 1/4p. | India | News item - legal |
DM201507-0521 2015 | Creamers Mining Weekly | Junior miners perceive Botswana as best investment destination. | Creamers Mining Weekly, June 3, 1/4p. | Africa, Botswana | News item - legal |
DM201507-0522 2015 | Creamers Mining Weekly | South Africa's geoscience desperately underfunded - Nedbank Capital comment. | Creamers Mining Weekly, June 5, 1/4p. | Africa, South Africa | News item - DMR |
DM201507-0523 2015 | Creamers Mining Weekly | Pioneering Botswana diamond circuit set for design run this month. Karowe | Creamers Mining Weekly, June 9, 2p. | Africa, Botswana | News item - Lucara |
DM201507-0524 2015 | Creamers Mining Weekly | Mining subtracting from Botswana's economic growth - economist. | Creamers Mining Weekly, June 9, 1/2p. | Africa, Botswana | News item - economics |
DM201507-0525 2015 | Creamers Mining Weekly | Botswana diamond beneficiation hits rough patch. | Creamers Mining Weekly, June 9, 1/2p. | Africa, Botswana | News item - Diamond Hub |
DM201507-0526 2015 | Creamers Mining Weekly | Lesotho govt processing sale of Mothae diamond stake. | Creamers Mining Weekly, June 9, 1/4p. | Africa, Lesotho | News item - Paragon |
DM201507-0527 2015 | Creamers Mining Weekly | Diamond miners show potential; as 4 declare dividends in last year. Alrosa, Dominion, Gem, Petra. | Creamers Mining Weekly, June 12, 3p. | Global | News item - dividends |
DM201507-0528 2015 | Creamers Mining Weekly | Alrosa does not see recovery in diamond prices this year. | Creamers Mining Weekly, June 16 1/4p. | Russia | News item - Alrosa |
DM201507-0529 2015 | Creamers Mining Weekly | Diamond industry in the midst of 'complicated times'. Blom. | Creamers Mining Weekly, June 15, 1/4p. | Global | News item - economics |
DM201507-0530 2015 | Creamers Mining Weekly | Diamond Corp offers 21 m shares to raise 2 million pounds. Lace | Creamers Mining Weekly, June 8, 1/4p. | Africa, South Africa | News item - DiamondCorp |
DM201507-0531 2015 | Creamers Mining Weekly | Uncertain future for global diamond trade as profits vanish. | Creamers Mining Weekly, June 25, 1/4p. | Global | News item - economics |
DM201507-0532 2015 | Creamers Mining Weekly | Rockwell to focus on production profile as Saxen drift output decreases. | Creamers Mining Weekly, June 25, 1/4p. | Africa, South Africa | News item - Rockwell |
DM201507-0533 2015 | Creamers Mining Weekly | Rio Tinto to sell stakes in Zim diamond, coal assets. Murowe | Creamers Mining Weekly, June 25, 1/4p. | Africa, Zimbabwe | News item - Rio Tinto |
DM201508-0534 2015 | Creamers Mining Weekly | Kimberley Diamonds secures debt fin ance for Botswana mine. From Chin a based auction house Zhejiang Huitong. Lerala | Creamers Mining Weekly, June 30, 1p. | Africa, Botswana | News item - Kimberley |
DM201508-0535 2015 | Creamers Mining Weekly | Diamond Corp raises 5 million lbs over subscribed offer. Lace | Creamers Mining Weekly, July 6, 1/4p. | Africa, South Africa | News item - DiamondCorp |
DM201508-0536 2015 | Creamers Mining Weekly | Madagascar to pass mining, petroleum bills in October - Minister. | Creamers Mining Weekly, July 10, 1/4p. | Africa, Madagascar | News item - legal |
DM201508-0537 2015 | Creamers Mining Weekly | Kimberley gets go ahead for Lerala. | Creamers Mining Weekly, July 20, 1/4p. | Africa, Botswana | News item - Kimberley Diamonds |
DM201508-0538 2015 | Creamers Mining Weekly | Amec launch of the UNCOVER Roadmap. …for greenfield exploration support. | Creamers Mining Weekly, July 21, 1p. | Australia | News item - AMEC |
DM201509-0539 2015 | Creamers Mining Weekly | Diamond miner De Beers Group has renewed gas and welding company Afrox contract ( Venetia) | Creamers Mining Weekly, Aug. 28, 1/4p. | Africa, South Africa | News item - De Beers |
DM201510-2004 2015 | Creamers Mining Weekly | Diamond, gold worth Rand 2 Million bust at Beitbridge. | Creamers Mining Weekly, Sept. 4, 1/4p. | Africa, South Africa, Democratic Republic of Congo | News item - legal |
DM201510-2005 2015 | Creamers Mining Weekly | Botswana's Debswana cuts diamond production due to market downturn. | Creamers Mining Weekly, Sept. 12, 1/4p. | Africa, Botswana | News item - Debswana |
DM201510-2006 2015 | Creamers Mining Weekly | Botswana Diamonds advances work at Orapa. | Creamers Mining Weekly, Sept. 12, 1/4p. | Africa, Botswana | News item - Botswana Diamonds, Alrosa |
DM201510-2007 2015 | Creamers Mining Weekly | Lucapa secures financing for Angolan expansion. | Creamers Mining Weekly, Sept. 14, 1/2p. | Africa, Angola | News item - Lucapa |
DM201510-2008 2015 | Creamers Mining Weekly | UAE chosen as Kimberley Process Chair. | Creamers Mining Weekly, Sept. 16, 1/4p. | United Arab Emirates | News item - KP |
DM201510-2009 2015 | Creamers Mining Weekly | Trans Hex diamond prices down in line with global slump. Somiluna | Creamers Mining Weekly, Sept. 16, 1/4p. | Africa, South Africa, Angola | News item - Trans Hex |
DM201510-2010 2015 | Creamers Mining Weekly | Sierra Leone economy to shrink one-fifth amid mining crisis. | Creamers Mining Weekly, Sept. 16, 1/4p. | Africa, Sierra Leone | News item - economics |
DM201510-2011 2015 | Creamers Mining Weekly | Kimberley Diamonds shares fall as former chairperson arrested ( false information to the market). | Creamers Mining Weekly, Sept. 16, 1/4p. | Australia | News item - Kimberley Diamonds |
DM201510-2012 2015 | Creamers Mining Weekly | Diamond sales to stabilize in 2015, long term outlook positive. | Creamers Mining Weekly, Sept. 22, 1/4p. | Global | News item - De Beers |
DM201510-2013 2015 | Creamers Mining Weekly | Diamond prices down on market weakness - Rockwell. | Creamers Mining Weekly, Sept. 22, 1/4p. | Africa, South Africa | News item - Rockwell |
DM201510-2014 2015 | Creamers Mining Weekly | Lucapa strikes it lucky in Angola… ten special diamonds. Lulo | Creamers Mining Weekly, Sept. 22, 1/4p. | Africa, Angola | News item - Lucapa |
DM201510-2015 2015 | Creamers Mining Weekly | Gemfields delivers maiden mineral resource, ore reserve estimates for Kagem. ( emerald) | Creamers Mining Weekly, Sept. 23, 1p. | Africa, Zambia | News item - Gemfields |
DM201511-2113 2015 | Creamers Mining Weekly | Lucapa recovers more special diamonds at Angola project. Lulo 90,56,36, 29 | Creamers Mining Weekly, Sept. 28, 1/4p. | Africa, Angola | News item - Lucapa |
DM201511-2114 2015 | Creamers Mining Weekly | Stornoway lifts Renard resources, sees ample exploration upside. | Creamers Mining Weekly, Sept. 28, 1/4p. | Canada, Quebec | News item - Stornoway |
DM201511-2115 2015 | Creamers Mining Weekly | The destruction of 95 % of South Africa's once bouyant diamond cutting and polishing industry showed once again that governments could not micromanage businesses. | Creamers Mining Weekly, Oct. 1, 1p. | Africa, South Africa | News item - cutting and polishing |
DM201511-2116 2015 | Creamers Mining Weekly | Paragon secures $ 15 million for Mothae, Lemphane development. | Creamers Mining Weekly, Oct. 2, 1p. | Africa, Lesotho | News item - Paragon |
DM201511-2117 2015 | Creamers Mining Weekly | Lucapa shares surge on kimberlite confirmation. ( Lulo area) | Creamers Mining Weekly, Oct. 6, 1/4p. | Africa, Angola | News item - Lucapa |
DM201511-2118 2015 | Creamers Mining Weekly | Botswana plans "bold" economic stimulus after diamond price drop. | Creamers Mining Weekly, Oct. 12, 1/4p. | Africa, Botswana | News item - economics |
DM201511-2119 2015 | Creamers Mining Weekly | Lucapa sells more Lulo diamonds. | Creamers Mining Weekly, Oct. 13, 1/4p. | Africa, Angola | News item - Lucapa |
DM201511-2120 2015 | Creamers Mining Weekly | Lucapa ups alluvial output. Lulo | Creamers Mining Weekly, Oct. 14, 1/4p. | Africa, Angola | News item - Lucapa |
DM201511-2121 2015 | Creamers Mining Weekly | Debt-heavy Rockwell juggles operating costs, repayment obligations in Q2 16th. October 2015. | Creamers Mining Weekly, Oct. 16, 1/4p. | Africa, South Africa | News item - Rockwell |
DM201511-2122 2015 | Creamers Mining Weekly | Now Oppenheimer properties edge out of De Beers' diamond route. | Creamers Mining Weekly, Oct. 20, 2p. | Africa, South Africa | News item - Oppenheimer |
DM201512-2216 2015 | Creamers Mining Weekly | Work together or perish together. State diamond trader commentary at Diamond Indaba 2015. | Creamers Mining Weekly, Oct. 27, 1p. | Africa, South Africa | News item - beneficiation |
DM201512-2217 2015 | Creamers Mining Weekly | Consider benefits of cross border diamond beneficiation. | Creamers Mining Weekly, Oct. 28, 1/4p. | Africa, South Africa, Botswana, Namibia | News item - economics |
DM201512-2218 2015 | Creamers Mining Weekly | Lucapa sells seventh parcel of Lulo diamonds. | Creamers Mining Weekly, Nov. 16, 1/4p. | Africa, Angola | News item - Lucapa |
DM201512-2219 2015 | Creamers Mining Weekly | Global industry comments by Zimnisky …. | Creamers Mining Weekly, Nov. 23, 3p. | Canada, global | News item - producers |
DM201512-2220 2015 | Creamers Mining Weekly | Canadian diamond producers best positioned to weather price crunch. | Creamers Mining Weekly, Nov. 24, 1/4p. | Canada | News item - producers |
DC201512-2422 2015 | Crystal Exploration Inc. | Crystal closes diamond projects acquisition. Muskox, Rush and James River properties. | Crystal Exploration Inc., Nov. 25, 1p. | Canada, Northwest Territories | News item - press release |
DS201508-0348 2015 | 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, Madagascar | Basanites, 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). |
DS201506-0261 2015 | Dannberg, J., Sobolev, S.V. | Low-bouyancy thermochemical plumes resolve controversy of classical mantle plume concept. | Nature Communications, Vol. 6, 6960 DOI: 10.1038 /ncomms7960 | Mantle | Magmatism |
DS201512-1907 2015 | D'Arpizio, C., Levato, F., Zito, D., De Montgolfier, J. | Luxury goods worldwide market study Fall-Winter 2014. | Bain & Company, Nov. 5, 38p. Pdf | Global | Diamond market |
DS201505-0232 2015 | Das, J.N. | Prospect of gemstones of India in 21st century. | Geological Society of America Annual Meeting, Oct. 24, 1p. Abstract | India | Gemstones |
DS201510-1764 2015 | Das, R., Saikia, U., Rai, S.S. | The deep geology of South India inferred from Moho depth and Vp/Vs ratio. | Geophysical Journal International, Vol. 203, pp. 910-926. | India | Geophysics - seismics |
| Abstract: We present a comprehensive study of thickness and composition of the crust; and the nature of crust-mantle boundary beneath Southern India using P-wave receiver function from 119 seismic stations. Data from distributed network of seismograph location encompass geological domains like mid to late Archean Dharwar craton, Archean and Proterozoic metamorphic terrains, Proterozoic basin, rifted margins and escarpments, and Deccan volcanics. Except for the mid to lower crust exhumed Archean terrains (of West Dharwar and Southern Granulite) all other geological domains have crustal thickness in the range 33-40 km. In the western Dharwar, crustal thickness increases from ?40 km in the north to over 50 km in the south. The Archean domain of granulite terrain is thicker (40-45 km) and more mafic compared to its counterpart in south deformed at 550 Ma. Most of the crustal blocks have low to moderate Vp/Vs (1.72-1.76) representing a felsic to intermediate composition. Exception to the above include Archean granulite terrain with high Vp/Vs (1.76–1.81) suggestive of more mafic crust beneath them. When accounted for the paleo burial depth of 15-25 km, the study suggests a possible Himalaya-Tibet like scenario beneath the mid-late Archean in southwestern Dharwar and north granulite terrain whose deeper crust has progressively densified. This led to a gradational crust-mantle transition that is otherwise sharp elsewhere. The study suggests a more homogenized and felsic nature of the Precambrian crust beneath the terrains formed after 2.6 Ga, possibly due to delamination of the mafic lower crust. Our study does not suggest any distinction between late Archean and Proterozoic crust. The Deccan volcanism at 65 Ma does not appear to have altered the crustal character beneath it and is similar to the adjoining late Archean east Dharwar craton. The western Ghat escarpment and the coastal plain formed due to separation of India from Madagascar are underlain by mafic lower crust. |
DS201503-0140 2015 | Dauteuil, O., Bessin, P., Guillocheau, F. | Topographic growth around the Orange River valley, southern Africa: a Cenozoic record of crustal deformation and climatic change. | Geomorphology, Vol. 233, March 15, pp. 5-19. | Africa, South Africa | Orange River |
| Abstract: We reconstruct the history of topographic growth in southern Africa on both sides of the Orange River valley from an integrated analysis of erosion surfaces, crustal deformation and climate change. First, we propose an inventory of erosion surfaces observed in the study area and classify them according to their most likely formative process, i.e. chemical weathering or mechanical erosion. Among the various land units observed we define a new class of landform: the pedivalley, which corresponds to a wide valley with a flat erosional floor. In the Orange River valley, we mapped three low-relief erosion surfaces, each bevelling a variety of lithologies. The oldest and most elevated is (1) a stripped etchplain evolving laterally into (2) a stepped pediplain bearing residual inselbergs; (3) a younger pediplain later formed in response to a more recent event of crustal deformation. These are all Cenozoic landforms: the etchplain is associated with a late Palaeocene to middle Eocene weathering event, and the two pediplains are older than the middle Miocene alluvial terraces of the Orange River. Landscape evolution was first driven by slow uplift (10 m/Ma), followed by a second interval of uplift involving a cumulative magnitude of at least 200 m. This event shaped the transition between the two pediplains and modified the drainage pattern. A final phase of uplift (magnitude: 60 m) occurred after the Middle Miocene and drove the incision of the lower terraces of the Orange River. Climate exerted a major control over the denudation process, and involved very humid conditions responsible for lateritic weathering, followed by more arid conditions, which promoted the formation of pedivalleys. Collectively, these produce pediplains. |
DS201509-0392 2015 | Davies, C., Pozzo, M., Gubbins, D., Alfe, D. | Constraints from material properties on the dynamics and evolution of Earth's core. | Nature Geoscience, Vol. 8, pp. 678-785. | Mantle | HT - core evolution |
| Abstract: The Earth’s magnetic field is powered by energy supplied by the slow cooling and freezing of the liquid iron core. Efforts to determine the thermal and chemical history of the core have been hindered by poor knowledge of the properties of liquid iron alloys at the extreme pressures and temperatures that exist in the core. This obstacle is now being overcome by high-pressure experiments and advanced mineral physics computations. Using these approaches, updated transport properties for FeSiO mixtures have been determined at core conditions, including electrical and thermal conductivities that are higher than previous estimates by a factor of two to three. Models of core evolution with these high conductivities suggest that the core is cooling much faster than previously thought. This implies that the solid inner core formed relatively recently (around half a billion years ago), and that early core temperatures were high enough to cause partial melting of the lowermost mantle. Estimates of core-mantle boundary heat flow suggest that the uppermost core is thermally stratified at the present day. |
DS201512-1908 2015 | Davies, D.R., Rawlinson, N., Iaffaldano, G., Campbell, I.H. | Lithospheric controls on magma composition along Earth's longest continental hotspot track. | Nature, Vol. 525, 7570, pp. 511-514. | Australia | Cosgrove track |
| Abstract: Hotspots are anomalous regions of volcanism at Earth’s surface that show no obvious association with tectonic plate boundaries. Classic examples include the Hawaiian-Emperor chain and the Yellowstone-Snake River Plain province. The majority are believed to form as Earth’s tectonic plates move over long-lived mantle plumes: buoyant upwellings that bring hot material from Earth’s deep mantle to its surface1. It has long been recognized that lithospheric thickness limits the rise height of plumes2, 3, 4 and, thereby, their minimum melting pressure. It should, therefore, have a controlling influence on the geochemistry of plume-related magmas, although unambiguous evidence of this has, so far, been lacking. Here we integrate observational constraints from surface geology, geochronology, plate-motion reconstructions, geochemistry and seismology to ascertain plume melting depths beneath Earth’s longest continental hotspot track, a 2,000-kilometre-long track in eastern Australia that displays a record of volcanic activity between 33 and 9 million years ago5, 6, which we call the Cosgrove track. Our analyses highlight a strong correlation between lithospheric thickness and magma composition along this track, with: (1) standard basaltic compositions in regions where lithospheric thickness is less than 110 kilometres; (2) volcanic gaps in regions where lithospheric thickness exceeds 150 kilometres; and (3) low-volume, leucitite-bearing volcanism in regions of intermediate lithospheric thickness. Trace-element concentrations from samples along this track support the notion that these compositional variations result from different degrees of partial melting, which is controlled by the thickness of overlying lithosphere. Our results place the first observational constraints on the sub-continental melting depth of mantle plumes and provide direct evidence that lithospheric thickness has a dominant influence on the volume and chemical composition of plume-derived magmas. |
DS201502-0052 2015 | Day, J.M.D. | Planet formation processes revealed by meteorites. | Geology Today, Vol. 31, 1, pp. 12-20. | Technology | Meteorite |
DC201501-1433 2014 | De Beers Canada Inc. | Gahcho Kue joint venture and NWT Metis Nation sign impact benefit agreement. | De Beers Canada , Dec. 15, 2p. | Canada, Northwest Territories | News item - press release |
DC201511-2374 2015 | De Beers Canada Inc. | De Beers Canada to move headquarters to Calgary from Toron to ( by June 2016) | De Beers Canada, Oct. 16, 1/2p. | Canada | News item - De Beers |
DC201502-1434 2014 | De Beers Group | Gahcho Kue joint venture and Deninu Kue First Nation sign impact benefit agreement. | De Beers Group, Dec. 24, 1p. | Canada, Northwest Territories | News item - press release |
DC201502-1435 2015 | De Beers Group | De Beers Group CEO steps out to support Forevermark "high impact" brand strategy. | De Beers Group, Jan. 8, 1p. | Global | News item - press release |
DC201502-1436 2015 | De Beers Group | De Beers announces 2015 auction sales programme for forward contract sales. | De Beers Group, Jan. 21, 1p. | Global | News item - press release |
DC201503-1440 2015 | De Beers Group | International institute of diamond grading & research set for Indian roadshow. | De Beers Group of Companies, Feb. 16, 1p. | India | News item - press release |
DC201505-1441 2015 | De Beers Group | Paul Rowley: we must all invest now to increase our future returns. VP of Global Sightholder Sales speaking at Dubai Diamond Conference. | De Beers Group of Companies, Apr. 21, 1p. | Global | News item - De Beers |
DC201506-1437 2015 | De Beers Group | De Beers seeks expression of interest for Kimberley Mines tailings Operation. | De Beers Group, May 21, 1p. | Africa, South Africa | News item - press release |
DC201507-1438 2015 | De Beers Group | Report to Society.. Building Forever 2014 | De Beers Group, June 5, | Global | News item - press release |
DC201507-1439 2015 | De Beers Group | Phillippe Mellier: Sustainable returns across the diamond pipeline are key to investment. | De Beers Group, June 16, 3p. | Global | News item - De Beers |
DC201508-1432 2015 | De Beers Group | Namibia and De Beers reach agreement on Milestone 10 year diamond sales agreement. | De Beers, July 21, 1p. | Africa, Namibia | News item - NDTC |
DC201510-2338 2015 | De Beers Group | 104 carat Forevermark diamond unveiled by long standing Forevermark Diamantaire … | De Beers Group, Sept. 7, 1p. | Hong Kong | News item - Cullinan Heritage |
DC201510-2339 2015 | De Beers Group | International Institute of diamond grading & research to launch synthetic melee screening and referrals testing service in India. | De Beers Group, Sept. 14, 1p. | India | News item - press release |
DC201510-2340 2015 | De Beers Group | Diamond industry fundamentals support long-term confidence in sector as India presents further growth opportunity. | De Beers Group, Sept. 21, 1p. | India | News item - press release |
DC201510-2341 2015 | De Beers Group | De Beers insight report 2015 - global consumer demand, rough diamond pipeline, in focus: the Indian consumer. | De Beers Group, 44p. | Global, India | News item - demand, piepline, consumer |
DC201511-2375 2015 | De Beers Group | International Institute of diamond grading & research launches melee testing service. HDGR low cost-high volume. | De Beers Group of Companies, Oct. 21, 1p. | India, Europe, Belgium | News item - De Beers |
DC201512-2423 2015 | De Beers Group | De Beers to launch social campaign to honour inspirational women globally. | news360.com, Nov. 10, 1/2p. | Global | News item - De Beers |
DC201512-2424 2015 | De Beers Group | Connecting resources and society conference to be held in Botswana. | De Beers Group of Companies, Nov. 13, 1p. | Africa, Botswana | News item - press release |
DC201510-2342 2015 | De Grey Mining Ltd. | De Grey opts out of agreement to acquire interest in diamond project. IIIP Prospect PR 856 in Kimberley district. | De Grey Mining Ltd., Sept. 8, 1p. | Africa, South Africa | News item - press release |
DS201512-1909 2015 | De Lamotte, F., Fourdan, D., Leleu, B., Leparmentier, S., Clarens, F. | Style of rifting and the stages of Pangea. | Tectonics, Vol. 34, 5, pp. 1009-1029. | Mantle | Pangea |
| Abstract: Pangea results from the progressive amalgamation of continental blocks achieved at 320?Ma. Assuming that the ancient concept of “active” versus “passive” rifting remains pertinent as end-members of more complex processes, we show that the progressive Pangea breakup occurred through a succession of rifting episodes characterized by different tectonic evolutions. A first episode of passive continental rifting during the Upper Carboniferous and Permian led to the formation of the Neo-Tethys Ocean. Then at the beginning of Triassic times, two short episodes of active rifting associated to the Siberian and Emeishan large igneous provinces (LIPs) failed. The true disintegration of Pangea resulted from (1) a Triassic passive rifting leading to the emplacement of the central Atlantic magmatic province (200?Ma) LIP and the subsequent opening of the central Atlantic Ocean during the lowermost Jurassic and from (2) a Lower Jurassic active rifting triggered by the Karoo-Ferrar LIP (183?Ma), which led to the opening of the West Indian Ocean. The same sequence of passive then active rifting is observed during the Lower Cretaceous with, in between, the Parana-Etendeka LIP at 135?Ma. We show that the relationships between the style of rifts and their breakdown or with the type of resulting margins (as magma poor or magma dominated) are not straightforward. Finally, we discuss the respective role of mantle global warming promoted by continental agglomeration and mantle plumes in the weakening of the continental lithosphere and their roles as rifting triggers. |
DS201503-0141 2015 | 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 Congo | Overview, 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. |
DS201503-0142 2015 | De Wit, M.C.J., Thorose, E. | Diamond bearing gravels along the lower Kwango River, DRC. | Geology and resource potential of the Congo Basin, Springer Regional Geology Reviews, Chapter 16, 20p. | Africa, Democratic Republic of Congo | Overview, history |
| Abstract: Since the mid-1950s the Kwango River has been a major target for alluvial diamonds which are and continue to be mined from its terraces, younger river flats and present-day river channel. The terraces have maximum ages of Early to Middle Pleistocene. Most of the diamonds have been recovered from large diamond placers in and along the Angolan section of this river—the Cuango River. Smaller deposits have been worked further downstream, where the Kwango River forms the international border between Angola and the Democratic Republic of Congo (DRC), also referred to as the ‘international’ Kwango. The prospecting history of this river goes back to 1906 but a systematic exploration program over the lower Kwango was only initiated in 2005. The application of geophysics to explore the terrace deposits and river flats has been very useful, but a programme of drilling and pitting was required to accurately define gravel and overburden thicknesses, and outline palaeo-channels. A diamond study used to glean information on diamond sizes and characteristics added significant value to the understanding of these alluvial deposits. For most of the international Kwango, terraces and river flats overly aeolian facies of Upper Kwango Group. Basement rocks, providing more favourable sites for diamond concentrations, are only exposed over a relatively short section, just upstream from Tembo. The basal part of the Cretaceous Kwango Group is locally composed of chemically mature gravels with diamonds in economic quantities only proximal to primary sources and no such settings were found in the project area. The size frequency of the diamonds from the international Kwango indicates that these form the distal head of the diamond trail that have been eroded out of the Cretaceous Kwango Group sediments and kimberlites in the Upper Cuango basin in Angola since the Pleistocene. The diamonds below the two major waterfalls along the international Kwango near Tembo, the Guiliame and Francois-Joseph Falls, show a high percentage of breakage and a decline in average diamond size from around 0.25 cts/stn above the falls to between 0.07 and 0.1 cts/stn in the Nzasi Muadi to Kitangu area between 20 km and 130 km below the Falls. However, local variations due to geomorphological influences affect diamond concentrations and sizes. A preliminary assessment of the terrace deposits suggests that these are uneconomic at present using modern mining methods. This is largely due to thick overburden (up to 12 m of sand) combined with thin and hence low-volume, medium-grade basal gravel, and the dominance of small diamonds of lower value. |
DS201509-0393 2015 | De Wit, R.W.L., Trampert, J. | Robust constraints on average radial lower mantle anisotropy and consequences for composition and texture. | Earth and Planetary Science Letters, Vol. 429, pp. 101-109. | Mantle | Seismic -anisotropy |
| Abstract: The seismic structure of Earth’s inner core is highly complex, displaying strong anisotropy and further regional variations. However, few seismic waves are sensitive to the inner core and fundamental questions regarding the origin of the observed seismic features remain unanswered. Thus, newtechniques to observe different types of inner corewaves are imperative to improve data coverage. Here, we detail our method for detecting exotic inner core phases such as PKJKP and PKIIKP, using inner core compressional waves as proof of concept.We use phase weighted stacking on long period data from a global distribution of stations, and employ several synthetic methods, including normal mode summation and SPECFEM, to identify and confirm the inner core phases. We present evidence for two observations of exotic inner core compressional waves, and apply the technique to a previously detected inner core shear wave. A possible new inner core shear wave remains unconfirmed. Additionally, we show how our method is important for rejecting potential observations, and distinguishing between waves with similar traveltime and slowness. The method is most successful for detecting exotic inner core compressional waves, and will provide a new approach for studying the compressional wave structures in the upper inner core. |
DC201502-1442 2015 | Debut Diamonds Inc. | Debut Diamonds Inc. completes private placement. $ 50,000. ( Macfadyen and Good Friday pipes) | Debut Diamonds Inc., Jna. 8, 1p. | Canada, Ontario, Attawapiskat | News item - press release |
DC201503-1443 2015 | Debut Diamonds Inc. | Debut Diamonds Inc. completes private placement. McFadyen | Debut Diamonds Inc., Jan. 27, 1p. | Canada, Ontario | News item - press release |
DS201511-1830 2015 | Decree, S., Boulvais, P., Tack, L., Andre, L., Baele, J-M. | Fluorapatite in carbonatite-related phosphate deposits: the case of the Matongo carbonatite. ( Burundi) | Mineralium Deposita, in press available 14p. | Africa, Burundi | Carbonatite |
| Abstract: The Matongo carbonatite intrusive body in the Neoproterozoic Upper Ruvubu alkaline plutonic complex (URAPC) in Burundi is overlain by an economic phosphate ore deposit that is present as breccia lenses. The ore exhibits evidence of supergene enrichment but also preserves textures related to the concentration of fluorapatite in the carbonatitic system. Magmatic fluorapatite is abundant in the ore and commonly occurs as millimeter-sized aggregates. It is enriched in light rare earth elements (LREE), which is especially apparent in the final generation of magmatic fluorapatite (up to 1.32 wt% LREE2O3). After an episode of metasomatism (fenitization), which led to the formation of K-feldspar and albite, the fluorapatite-rich rocks were partly brecciated. Oxygen and carbon isotope compositions obtained on the calcite forming the breccia matrix (?18O?=?22.1?- and ?13C?=??1.5?‰) are consistent with the involvement of a fluid resulting from the mixing of magmatic-derived fluids with a metamorphic fluid originating from the country rocks. In a subsequent postmagmatic event, the carbonates hosting fluorapatite were dissolved, leading to intense brecciation of the fluorapatite-rich rocks. Secondary carbonate-fluorapatite (less enriched in LREE with 0.07-0.24 wt% LREE2O3 but locally associated with monazite) and coeval siderite constitute the matrix of these breccias. Siderite has ?18O values between 25.4 and 27.7?- and very low ?13C values (from ?12.4 to ?9.2?, which are consistent with the contribution of organic-derived low ?13C carbon from groundwater. These signatures emphasize supergene alteration. Finally, the remaining voids were filled with a LREE-poor fibrous fluorapatite (0.01 wt% LREE2O3), forming hardened phosphorite, still under supergene conditions. Pyrochlore and vanadiferous magnetite are other minerals accumulated in the eluvial horizons. As a consequence of the supergene processes and fluorapatite accumulation, the phosphate ore, which contains 0.72 to 38.01 wt% P2O5, is also enriched in LREE (LaN/YbN from 47.1 to 83.5; ?REE between 165 and 5486 ppm), Nb (up to 656 ppm), and V (up to 1232 ppm). In the case of phosphate exploitation at Matongo, REE could prove to have a subeconomic potential to be exploited as by-products of phosphates. |
DS201511-1831 2015 | Deljanin, B., Alessandri, M., Peretti, A., Astrom, M. | NDT breaking the 10 carat barrier: world record faceted and gem-quality synthetic diamonds. | Contributions to Gemology, Vol. 15, pp. 1-7. | Technology | Synthetics |
| Abstract: The first small manufactured industrial diamonds were produced in 1953 by the Swedish company ASEA but their accomplishment went unannounced. In 1970, General Electric (GE) produced synthetic diamond crystals using the HPHT method with a belt type of press and created a 0.78ct polished RBC colorless diamond. In the 1980’s and 1990’s Russians used their own technology (“BARS” and “TOROID” high pressure apparatus (HPA) with high pressure presses of up to 25 MN load) to grow industrial and crystals up to 2.00ct in polished size, mostly orange to yellow in colour. In the last 15 years, companies including Lucent, Chatham, AOTC, Gemesis (now IIa Technologies) and many other producers in China, Germany, India, Russia, Ukraine, USA and Taiwan have improved the technology yet again and used their expertise to successfully grow diamond crystals that cut to 1.00ct up to 2.00ct in size. This “next generation” of diamonds exhibited high clarities (VS and VVS) and colours (D-H), as well as new blue and pink colours (after irradiation). Other companies (ref. 2-3) including Scio Diamonds, Washington Diamonds, Taidiam, PDC diamonds and Pure Grown Diamonds (selling arm of IIa technologies) are also using a very different technology/process of Chemical Vapour Deposition (CVD) to produce laboratory-grown diamonds up to 3.00 ct in size (table 1). |
DS201504-0192 2014 | Delpit, S., Ross, P-S., Hearn, B.C. | Deep bedded ultramafic diatremes in the Missouri River Breaks volcanic field, Montana, USA. | Bulletin of Volcanology, Vol. 76, p. 832- | United States, Montana | Diatreme |
DS201506-0263 2015 | DeStefano, A., Shiroki, A., Zhuk, V., Gaudet, M. | Detailed studies of Renard 2 kimberlite - some practical aspects. | Vancouver Kimberlite Cluster, May 27, 1/4p. Abstract | Canada, Quebec | Deposit - Renard |
DM201511-2123 2015 | Devenish, C. | Charles is a strong environmenta list in India and asks that mining and agriculture support each other. Articles by Colin Todhunter | ColinTodHunter.com, charlesdevenish @geomysore.com | India | News item - CSR |
DS201502-0053 2010 | deVera, J., Granado, P., McClay, K. | Structural evolution of the Orange Basin gravity-driven system, offshore Namibia. | Marine and Petroleum Geology, Vol. 27, 1, pp. 223-237. | Africa, Namibia | Structure |
DS201501-0006 2014 | Devriese, S.G.R., Corcoran, N., Cowan, D., Davis, K., Bild-Enkin, D., Fournier, D., Heagy, L., Kang, S., Marchant, D., McMillan, M.S., Mitchell, M., Rosenkjar, G., Yang, D., Oldenburg, D.W. | Magnetic inversion of three airborne dat a sets over the Tli Kwi Cho kimberlite complex. | SEG Annual Meeting Denver, 5p. Extended abstract | Canada, Northwest Territories | Deposit - Tli Kwi Cho, geophysics |
| Abstract: The magnetic and electromagnetic responses from airborne systems at Tli Kwi Cho, a kimberlite complex in the Northwest Territories, Canada, have received considerable attention over the last two decades but a complete understanding of the causative physical properties is not yet at hand. Our analysis is distributed among three papers. In the first, we find a 3D magnetic susceptibility model for the area; in the second, we find a 3D conductivity model; and in the third paper, we find a 3D chargeability model. Our goal is to explain all the geophysical results within a geologic framework. In this first paper, we invert three independent airborne magnetic data sets flown over the Tli Kwi Cho kimberlite complex located in the Lac de Gras kimberlite field in Northwest Territories, Canada. The complex consists of two kimberlites known as DO-27 and DO-18. An initial airborne DIGHEM survey was flown in 1992 and AeroTEM and VTEM data subsequently acquired in 2003 and 2004, respectively. In this paper, we invert each magnetic data set in three dimensions. Both kimberlites are recovered in each model, with DO-27 as a more susceptible body than DO-18. Our goal is to simultaneously invert the three data sets to generate a single susceptibility model for Tli Kwi Cho. This project is part of a larger, on-going investigation by UBC-GIF on inverting magnetic, electromagnetic, and induced polarization data from the Tli Kwi Cho area. |
DS201503-0143 2015 | Dey, S., Nandy, J., Choudhary, A.K., Liu, Y., Zong, K. | Neoarchean crustal growth by combined arc-plume action: evidence from the Kadiri greenstone belt, eastern Dharwar craton, India. | Geological Society of London Special Publication: Continent formation through time., No. 389, pp. 135-163. | India | Geotectonics |
| Abstract: Field and geochemical studies combined with laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) zircon U-Pb dating set important constraints on the timing and petrogenesis of volcanic rocks of the Neoarchaean Kadiri greenstone belt and the mechanism of crust formation in the eastern Dharwar craton (EDC). The volcanic rocks are divided into three suites: tholeiitic basalts, calc-alkaline high-Mg# andesites and dominant dacites-rhyolites. The basalts (pillowed in places) show flat rare earth element (REE) and primordial mantle-normalized trace element patterns, but have minor negative Nb and Ta anomalies. They are interpreted as mantle plume-related oceanic plateau basalts whose source contained minor continental crustal input. The andesites are characterized by high Mg# (0.66-0.52), Cr and Ni, with depletion of high-field strength elements (HFSE) and enrichment of light REE (LREE) and large-ion lithophile elements (LILE). They were probably derived from a metasomatized mantle wedge overlying a subducted slab in a continental margin subduction zone. The dacites-rhyolites are silicic rocks (SiO2 = 61-72 wt%) with low Cr and Ni, K2O/Na2O mostly 0.5-1.1, highly fractionated REE patterns, enrichments of LILE and distinctly negative HFSE anomalies. One rhyolite sample yielded a zircon U-Pb age of 2353 ± 32 Ma. This suite is similar to potassic adakites and is explained as the product of deep melting of thickened crust in the arc with a significant older crustal component. Collision between a continental margin arc with an oceanic plateau followed by slab break-off, upwelling of hot asthenosphere and extensive crustal reworking in a sustained compressional regime is proposed for the geodynamic evolution of the area. This is in corroboration with the scenario of EDC as a Neoarchaean hot orogen as suggested recently by some workers. |
DS201512-1910 2015 | 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. | Technology | Synthetics |
| 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. |
DS201508-0349 2015 | Dhuime, B., Wuestefeld, A., Hawkesworth, C.J. | Emergence of modern continental crust about 3 billion years ago. | Nature Geoscience, Vol. 8, pp. 552-555. | Mantle | Geochronology Rb/Sr |
DC201507-1444 2015 | Diamante Minerals, Inc. | Diamante provides update on Mineracao Batovi diamond project. | Diamante Minerals, Inc., June 5, 2p. | South America, Brazil, Mato Grosso | News item - press release |
DC201508-1445 2015 | Diamante Minerals, Inc. | Announces new chief financial officer. Batovi | Diamante Minerals, Inc., July 9, 1p. | South America, Brazil, Mato Grosso | News item - press release |
DC201501-1446 2014 | Diamcor Mining Inc. | MD&A ended Sept. 30, 2014 - Corporate highlights Krone-Endora. | Diamcor Mining Inc., Dec. 1, 1p. | Africa, South Africa | News item - press release |
DC201501-1447 2014 | Diamcor Mining Inc. | Diamcor achieves significant milestone in second fiscal quarter. A full mining right from the South African Dept. of Minerals and resources in respect of Krone-Endora. | Diamcor Mining Inc., Dec. 4, 2p. | Africa, South Africa | News item - press release |
DC201502-1448 2014 | Diamcor Mining Inc. | Diamcor closes private placement of CDB $ 3,133,600 | Diamcor Mining Inc., Dec. 31, 1p. | Africa, South Africa | News item - press release |
DC201503-1449 2015 | Diamcor Mining Inc. | Diamcor commences expansion/ targets implementation. Krone-Endora | Diamcor Mining Inc., Feb. 5, 1p. | Africa, South Africa | News item - press release |
DC201504-1450 2015 | Diamcor Mining Inc. | Diamcor third quarter fiscal 2015 results. Krone-Endora | Diamcor Mining Inc., Feb. 26, 2p. | Africa, South Africa | News item - press release |
DC201505-1451 2015 | Diamcor Mining Inc. | Fourth quarter diamond sales and upgrade progress at Krone-Endor at Venetia. | Diamcor Mining Inc., Apr. 15, 4p. | Africa, South Africa | News item - press release |
DC201506-1452 2015 | Diamcor Mining Inc. | Diamcor files updated technical report for Krone-Endora at Venetia project. | Diamcor Mining Inc., Apr. 28, 2p. | Africa, South Africa | News item - press release |
DC201508-1453 2015 | Diamcor Mining Inc. | Diamcor first quarter diamond sales and operational update at Krone-Endora at Venetia. | Diamcor Mining Inc., July 20, 2p. | Africa, South Africa | News item - press release |
DC201511-2376 2015 | Diamcor Mining Inc. | Diamcor second fiscal quarter sales and operational update at Krone-Endora at Venetia. | Diamcor Mining Inc., Oct. 6, 3p. | Africa, South Africa | News item - press release |
DC201512-2425 2015 | Diamcor Mining Inc. | Diamcor preparing for largest rough diamond tender to date. Krone-Endora | Diamcor Mining Inc., Oct. 30, 1p. | Africa, South Africa | News item - press release |
DC201507-1454 2015 | Diamond Fields International Ltd. | Diamond Fields International restarts Namibian diamond operations. | Diamond Fields International Ltd., June 5, 1p. | Africa, Namibia | News item - press release |
DC201512-2426 2015 | Diamond Fields International Ltd. | Diamond Fields is pleased to announce that offshore marine sampling operations have begun ML-111 | Diamond Fields International Ltd., Nov. 16, 1p. | Africa, Namibia | News item - press release |
DM201512-2326 2015 | Diamond Intelligence Briefing | De Beers defers its own Debswana rough purchases. | Diamond Intellgence Briefing, Nov. 12, 7p. | Africa, Botswana | News item - De Beers |
DM201502-0544 2015 | Diamond Investing News | What are nanodiamonds ( outline for the layman) | Diamond Investing News, Jan. 1, 1p. | Technology | News item - nanodiamonds |
DM201504-0545 2015 | Diamond Investing News | Trans Hex announces an update of latest diamond sales and production. | Diamond Investing News, Mar. 5, 1/4p. | Africa, South Africa | News item - Trans Hex |
DM201507-0546 2015 | Diamond Investing News | 5 top industrial diamond producing countries ( DRC, Russia, Australia, Botswana, South Africa) | diamondinvestingnews.com, June 18, 2p. | Global | News item - industrial diamonds |
DM201508-2466 2015 | Diamond Investing news | High hopes for Lucara Diamond's first 2015 exceptional stone tender. | Diamond Investing News, July 13, 1p. | Africa, Botswana | News item - Lucara |
DM201511-2208 2015 | Diamond Investing News | Can miners buck the diamond price trend 2015? | Diamond Investing News, Oct. 19, 2p. | Global | News item - prices |
DC201509-1456 2015 | DiamondCorp plc. | Lace diamond mine project update. Upper K4 unit. | DiamondCorp plc., July 31, 4p. | Africa, South Africa | News item - press release |
DC201510-2343 2015 | DiamondCorp Plc. | Interim results…. Lace mine. | DiamondCorp Plc., Sept. 1, 4p. | Africa, South Africa | News item - press release |
DC201511-2377 2015 | DiamondCorp Plc. | Conveyor belt installation complete ( 400 tonne per hour) at Lace mine. | DiamondCorp. Plc, Oct. 13, 2p. | Africa, South Africa | News item - press release |
DC201512-2427 2015 | DiamondCorp plc. | Lace diamond mine project update … detailed. | DiamondCorp plc, Nov. 3, 1p. | Africa, South Africa | News item - press release |
DC201512-2428 2015 | DiamondCorp plc. | Conveyor belt commissioned. Lace mine | DiamondCorp plc, Nov. 12, 1p. | Africa, South Africa | News item - press release |
DC201512-2429 2015 | DiamondCorp plc. | Lace mine - 290m level development resumes. | DiamondCorp plc, Nov. 20, 1p. | Africa, South Africa | News item - press release |
DS201512-1911 2015 | Diamonds in Canada | Big changes at De Beers Canada.. New CEO discusses HQ move to Calgary. | Diamonds in Canada Magazine, Northern Miner, Nov. pp. 18-19. | Canada, Alberta | De Beers Headquarters |
DS201512-1912 2015 | Diamonds in Canada | Stornoway benefits from 'good timing'. Renard on track for commercial production in 2017. | Diamonds in Canada Magazine, Northern Miner, Nov. pp. 20-21. | Canada, Quebec | Deposit - Renard |
DS201512-1913 2015 | Diamonds in Canada | Sable PEA sweetens Ekati. Dominion works to add mine life to operation. | Diamonds in Canada Magazine, Northern Miner, Nov. 22-23. | Canada, Northwest Territories | Deposit - Sable |
DM201501-0547 2014 | Diamonds.net | Anjin's failed promise turns former Marange nonagenarian destitute. | Diamonds.net, Dec. 1, 1/4p. | Africa, Zimbabwe | News item - Anjin |
DM201501-0548 2014 | Diamonds.net | Sierra Leone issues investor statement on Sunergy Inc. License from NWA false. | Diamonds.net, Dec. 1, 1/4p. | Africa, Sierra Leone | News item - Sunergy |
DM201501-0549 2014 | Diamonds.net | Firestone on track to commence Liquobong production in 2Q 2016. | Diamonds.net, Dec. 2, 1/4p. | Africa, Lesotho | News item - Firestone |
DM201501-0550 2014 | Diamonds.net | Argyle Champagne diamond raises money for women in mining internship. | Diamonds.net, Dec. 4, 1/4p. | Global, England | News item - Argyle, Rio Tinto |
DM201501-0551 2014 | Diamonds.net | The diamond decade so far. | Diamonds.net, Dec. 5, 2p. | Global | News item - history |
DM201501-0552 2014 | Diamonds.net | Liori Diamonds engagement survey shows growing interest in black diamonds. | Diamonds.net, Dec. 3, 1p. | Global | News item - Liori |
DM201501-0553 2014 | Diamonds.net | Venezuela adds diamonds to financial reserves to strengthen security and currency. Withdrew from KP in 2008. No Venezuelan reports to date ( suspected smuggling through Brazil and Guyana). | Diamonds.net, Dec. 5, 1/4p. | South America, Venezuela | News item - legal |
DM201501-0554 2014 | Diamonds.net | President Putin, Prime Minister Modi to address World Diamond Conference. | Diamonds.net, Dec. 7, /4p. | India | News item - GJEPC |
DM201501-0555 2014 | Diamonds.net | Lace mine workers end strike, resume work on Dec. 8. | Diamonds.net, Dec. 7, /4p. | Africa, South Africa | News item - DiamondCorp |
DM201501-0556 2014 | Diamonds.net | Stellar Diamonds prepares Baoule rough for sale in Antwerp. | Diamonds.net, Dec. 4, 1/4p. | Africa, Guinea | News item - Stellar |
DM201501-0557 2014 | Diamonds.net | Diamond explorer ( Delrand) votes on plan to sell Congo Licenses for $1 | Diamonds.net, Dec. 7, /4p. | Africa, Democratic Republic of Congo | News item - Delrand |
DM201501-0558 2014 | Diamonds.net | Consumers starting to embrace lab-grown diamonds. | Diamonds.net, Dec. 7, /4p. | Technology | News item - Diamaz International |
DM201501-0559 2014 | Diamonds.net | AWDC and Bain & Co. release fourth annual diamond industry report. SEE Technical refs for full report ref. | Diamonds.net, Dec. 9, 1/4p. | Global | News item - Bain |
DM201501-0560 2014 | Diamonds.net | Belgium's competition authority dismisses Spira's complaint against De Beers. | Diamonds.net, Dec. 8, 1/4p. | Europe, Belgium | News item - De Beers |
DM201501-0561 2014 | Diamonds.net | Rio Tinto's Partnership model to drive diamond jewelry growth in India. | Diamonds.net, Dec. 11, 1/4p. | India | News item - Rio Tinto |
DM201501-0562 2014 | Diamonds.net | Lucara sets top revenue target at $ 240 million for 2015. | Diamonds.net, Dec. 11, 1/4p. | Africa, Botswana | News item - Lucara |
DM201501-0563 2014 | Diamonds.net | Alrosa takes measures to improve liquidity. | Diamonds.net, Dec. 12, 1/4p. | Russia | News item - Alrosa |
DM201501-0564 2014 | Diamonds.net | Sightholders reject goods at $600 m December De Beers sight. | Diamonds.net, Dec. 16, 1/4p. | Global | News item - De Beers |
DM201501-0565 2014 | Diamonds.net | Cote d'Ivoire resumes diamond trade with Belgian help. | Diamonds.net, Dec. 16, 1/4p. | Africa, Ivory Coast | News item - KP |
DM201501-0566 2014 | Diamonds.net | Gahcho Kue operators sign impact agreement with Metis Nation. | Diamonds.net, Dec. 15, 1/4p. | Canada, Northwest Territories | News item - De Beers, Mountain Province |
DM201501-0567 2014 | Diamonds.net | Nasdaq approves listing for Mountain Province Diamonds. | Rough-Polished.com, Dec. 19, 1/4p. | Canada, Northwest Territories | News item - Mountain Province |
DM201501-0568 2014 | Diamonds.net | Lucapa to start alluvial mining at Lulo in January. | Diamonds.net, Dec. 18, 1/4p. | Africa, Angola | News item - Lucapa |
DM201502-0569 2014 | Diamonds.net | Diamond grade improves in the latest Kelvin mini-bulk sample. | Diamonds.net, Dec. 24, 1/4p. | Canada, Northwest Territories | News item - Kennady |
DM201502-0570 2014 | Diamonds.net | Decree taps Alrosa, Kristall to reduce foreign currency holdings. | Diamonds.net, Dec. 24, 1/4p. | Russia | News item - Alrosa, Kristall |
DM201502-0571 2014 | Diamonds.net | Peregrine Diamonds placement to raise $ 2 million. | Diamonds.net, Dec. 22, 1/4p. | Canada, Nunavut, Baffin Island | News item - Peregrine |
DM201502-0572 2014 | Diamonds.net | Lukoil targets production of 2 million carats in 2015. | Diamonds.net, Dec. 29, 1/4p. | Russia, Kola Peninsula, Archangel | News item - Lukoil |
DM201502-0573 2014 | Diamonds.net | SRK signs supply contract with Alrosa. | Diamonds.net, Dec. 29, 1/4p. | Russia | News item - SRK, Alrosa |
DM201502-0574 2014 | Diamonds.net | The diamond story of 2014…. Reduction of bank credit available is a game changer. | Diamonds.net, Dec. 26, 4p. | Global | News item - economics |
DM201502-0575 2014 | Diamonds.net | Mbada Diamonds workers picket for unpaid salary. | Diamonds.net, Dec. 24, 1/4p. | Africa, Zimbabwe | News item - Mbada |
DM201502-0576 2014 | Diamonds.net | Russia orders Alrosa, Kristall to sell foreign currency. | Diamonds.net, Dec. 23, 1/4p. | Russia | News item - Alrosa, Kristall |
DM201502-0577 2014 | Diamonds.net | Sarine delivers its first Galaxy ultra microscopic inclusion mapping service. | Diamonds.net, Dec. 30, 1/4p. | Technology | News item - Sarine |
DM201502-0578 2015 | Diamonds.net | Stellar Diamonds postpones first Baoule diamond sale to late January. | Diamonds.net, Jan. 7, 1/4p. | Africa, Guinea | News item - Stellar |
DM201502-0579 2015 | Diamonds.net | WDC website posts system of warranties guidelines. | Diamonds.net, Jan.7, 1/4p. | Technology | News item - WDC |
DM201502-0580 2015 | Diamonds.net | Rio Tinto's 4 Q diamond production -37%. Argyle and Diavik | Diamonds.net, Jan. 20, 1/4p. | Australia, Canada, Northwest Territories | News item - Rio Tinto |
DM201502-0581 2015 | Diamonds.net | Advanced HPHT takes lab grown diamonds to new level. One carat flawless | Diamonds.net, Jan. 20, 1/4p. | Technology | News item - Diamaz International |
DM201502-0582 2015 | Diamonds.net | Lucapa receives $ 15 m bridge financing. Lulo | Diamonds.net, Jan. 23, 1/4p. | Africa, Angola | News item - Lucapa |
DM201502-0583 2015 | Diamonds.net | Okavango Diamond Company completed first year in business. | Diamonds.net, Jan. 23, 1/4p. | Africa, Botswana | News item - Okavango |
DM201502-0584 2015 | Diamonds.net | Petra's 1 H production -2% to 1.6 m carats. | Diamonds.net, Jan. 26, 1/4p. | Africa, South Africa | News item - Petra |
DM201502-0585 2015 | Diamonds.net | Rio Tinto publishes 17 select diamantaires for 2015. | Diamonds.net, Jan. 26, 1/4p. | Global | News item - Rio Tinto |
DM201503-0586 2015 | Diamonds.net | GIA revises colored stone reports. | Diamonds.net, Jan. 29, 1/4p. | Technology | News item - GIA |
DM201503-0587 2015 | Diamonds.net | Alrosa plans 2015 production +5% to 40 m carats. | Diamonds.net, Jan. 29, 1/4p. | Russia | News item - Alrosa |
DM201503-0588 2015 | Diamonds.net | Gem Diamonds Letseng sales - 10% in 4Q. | Diamonds.net, Jan. 27, 1p. | Africa, Lesotho | News item - Gem Diamonds |
DM201503-0589 2015 | Diamonds.net | De Beers January sight estimated at $ 450 M. | Diamonds.net, Jan. 27, 1p. | Global | News item - De Beers |
DM201503-0590 2015 | Diamonds.net | Diamond Corp reports $ 1.4 m sales in 2014. | Diamonds.net, Feb. 1, 1/4p. | Africa, South Africa | News item - DiamondCorp |
DM201503-0591 2015 | Diamonds.net | US says Edwards sane enough to stand trial in diamond fraud case. | Diamonds.net, Jan. 30, 1/4p. | United States | News item - CMKM |
DM201503-0592 2015 | Diamonds.net | Minister urges Zimbabwe's youth to take charge of diamond mining. Chiadzwa | Diamonds.net, Jan 30, 1/4p. | Africa, Zimbabwe | News item - legal |
DM201503-0593 2015 | Diamonds.net | New Zimbabwe tax scheme makes Murowa unprofitable. | Diamonds.net, Jan. 30, 1/4p. | Africa, Zimbabwe | News item - legal |
DM201503-0594 2015 | Diamonds.net | Heavy traffic expected on Canada's diamond ice road. | Diamonds.net, Feb. 3, 1/4p. | Canada, Northwest Territories | News item - ice road |
DM201503-0595 2015 | Diamonds.net | Alrosa expects to sell 2 m carats from inventory in 2015. | Diamonds.net, Feb. 4, 1/4p. | Russia | News item - Alrosa |
DM201503-0596 2015 | Diamonds.net | Alrosa, Israel sign cooperation agreement… exchange of expertise | Diamonds.net, Feb. 9, 1/4p. | Russia, Europe, Israel | News item - Alrosa |
DM201503-0597 2015 | Diamonds.net | Minister is unimpressed with diamond miners, tells NGOs to stay out of politics. | Diamonds.net, Feb. 9, 1/4p. | Africa, Zimbabwe | News item - legal |
DM201503-0598 2015 | Diamonds.net | Kennady Diamonds private placement to raise $ 16 m. | Diamonds.net, Feb. 9, 1/4p. | Canada, Northwest Territories | News item - Kennady |
DM201503-0599 2015 | Diamonds.net | North Arrow's drilling program is underway at the Pikoo diamond project. | Diamonds.net, Feb. 11, 1/4p. | Canada, Saskatchewan | News item - North Arrow |
DM201503-0600 2015 | Diamonds.net | Alrosa relaxes client sales volume requirements but not prices. | Diamonds.net, Feb. 11, 1/4p. | Russia | News item - Alrosa |
DM201503-0601 2015 | Diamonds.net | Rio Tinto's diamond revenue +6 % to $901 m in 2014. | Diamonds.net, Feb. 12, 1/4p. | Global | News item - Rio Tinto |
DM201503-0602 2015 | Diamonds.net | Stable rough diamond production. | Diamonds.net, Feb. 6, 2p. | Global | News item - production |
DM201503-0603 2015 | Diamonds.net | De Beers profit, revenue soar in 2014. 74% jump to $ 923 million. | Diamonds.net, Feb. 13, 1/4p. | Global | News item - De Beers |
DM201503-0604 2015 | Diamonds.net | Sotheby's to offer 100 carat emerald cut diamond at April auction. Dubbed the "Ultimate emerald cut diamond". De Beers stone mined in southern Africa. | Diamonds.net, Feb. 13, 1/4p. | Technology | News item - diamond notable |
DM201503-0605 2015 | Diamonds.net | Diamond Corp secures wage agreement for Lace mine workers. | Diamonds.net, Feb. 18,1 /4p. | Africa, South Africa | News item - DiamondCorp |
DM201503-0606 2015 | Diamonds.net | Diavik Diamond Mines, Crossworks Manufacturing sponsor Yellowknife Gala. | Diamonds.net, Feb. 20, 1/4p. | Canada, Northwest Territories | News item - Diavik |
DM201503-0607 2015 | Diamonds.net | Alrosa seeks to buy 33% of Catoca production. | Diamonds.net, Feb. 19, 1/4p. | Africa, Angola, Russia | News item - Alrosa |
DM201504-0608 2015 | Diamonds.net | Lucapa clears bridge loan requirements and raises $ 5 million. | Diamonds.net, Mar.3, 1p. | Africa, Angola | News item - Lucapa |
DM201504-0609 2015 | Diamonds.net | Average rough prices drop for Trans Hex. | Diamonds.net, Mar.3, 1/4p. | Africa, South Africa | News item - Trans Hex |
DM201504-0610 2015 | Diamonds.net | GIA & De Beers to speak on synthetic diamonds March 22. Panel discussion at GIA | Diamonds.net, Mar.3, 1/4p. | United States | News item - synthetics |
DM201504-0611 2015 | Diamonds.net | De Beers Feb. sight estimated at $ 550 million. | Diamonds.net, Mar. 3, 1/4p. | Global | News item - De Beers |
DM201504-0612 2015 | Diamonds.net | Zimbabwe prepares for no diamond revenue in 2015. | Diamonds.net, Mar. 6, 1/4p. | Africa, Zimbabwe | News item - legal |
DM201504-0613 2015 | Diamonds.net | Diamond miners meet to set up consumer promotion body. Rio Tinto, De Beers, Alrosa, Petra, Gem, Lucara, Dominion, LuKoil | Diamonds.net, Mar. 9, 1/4p. | Global | News item - promo |
DM201504-0614 2015 | Diamonds.net | Alrosa feels weaker demand, sizable inventory levels in the pipeline. | Diamonds.net, Mar. 10, 1/4p. | Russia | News item - Alrosa |
DM201504-0615 2015 | Diamonds.net | Chidhakwa's plan creates just one diamond miner in Marange. | Diamonds.net, Mar. 13, 1/4p. | Africa, Zimbabwe | News item - legal |
DM201504-0616 2015 | Diamonds.net | Turkey targets growth in diamond trading. | Diamonds.net, Mar. 13, 1/4p. | Europe, Turkey | News item - jewellery |
DM201504-0617 2015 | Diamonds.net | Antwerp diamond industry launches offensive in Latin America. Brazil in particular. | Diamonds.net, Mar. 11, 1p. | South America, Brazil | News item - markets |
DM201504-0618 2015 | Diamonds.net | Sarine debuts its profile technology. | Diamonds.net, Mar. 16, 1/4p. | Technology | News item - Sarine |
DM201504-0619 2015 | Diamonds.net | Russian diamond sales unaffected by economic crisis. | Diamonds.net, Mar. 16, 1/4p. | Russia | News item - Alrosa |
DM201504-0620 2015 | Diamonds.net | Zimbabwe lost $ 12 billion to illegal multinational business practices. | Diamonds.net, Mar. 18, 1/4p. | Africa, Zimbabwe | News item - legal |
DM201504-0621 2015 | Diamonds.net | De Beers upgrades DiamondView. | Diamonds.net, Mar. 18, 1/4p. | Technology | News item - DiamondView |
DM201504-0622 2015 | Diamonds.net | Gem Diamonds profit +57% to $ 33 m in 2014. | Diamonds.net, Mar. 17, 1/4p. | Africa, Lesotho | News item - Gem Diamonds |
DM201504-0623 2015 | Diamonds.net | Fancy Color Research Foundation launches mobile website. | Diamonds.net, Mar. 19, 1/4p. | Technology | News item - FCRF |
DM201504-0624 2015 | Diamonds.net | Alrosa reports liss in 2014, revenu + 23% ( foreign exchange loss) | Diamonds.net, Mar. 23, 1/4p. | Russia | News item - Alrosa |
DM201504-0625 2015 | Diamonds.net | Yellow diamond leads Sotheby's HK spring sale. | Diamonds.net, Mar. 23, 1/4p. | Global | News item - diamond notable |
DM201504-0626 2015 | Diamonds.net | Journa list faces defamation trial for exposing Angolan diamonds abuses. Marquis de Morais | Diamonds.net, Mar. 22, 1p. | Africa, Angola | News item - legal |
DM201504-0627 2015 | Diamonds.net | De Beers to open first diamond grading institute in Surat. | Diamonds.net, Mar. 23, 1/4p. | India | News item - De Beers |
DM201504-0628 2015 | Diamonds.net | Merlin Diamonds receives $ 5 million to restart production. ( Govt tax refund). | Diamonds.net, Mar. 23, 1/4p. | Australia | News item - Merlin |
DM201504-0629 2015 | Diamonds.net | Angolan court slaps additional charges on Marques de Morais ( exposed corruption in diamond industry in Angola). | Diamonds.net, Mar. 25, 1/4p. | Africa, Angola | News item - legal |
DM201504-0630 2015 | Diamonds.net | GA adopts Sarine's Instructor as standard software. | Diamonds.net, Mar. 25, 1/4p. | Technology | News item - Sarine |
DM201504-0631 2015 | Diamonds.net | Diamond smuggling thrives in CAR. | Diamonds.net, Mar. 25, 1/4p. | Africa, Central African Republic | News item - legal |
DM201505-0632 2015 | Diamonds.net | Teeling says diamonds shine in a resource world filled with gloom. | Diamonds.net, Mar. 27, 1/4p. | Global | News item - Botswana Diamonds |
DM201505-0633 2015 | Diamonds.net | Stellar Diamonds narrows loss, seeks to raise $ 20 m. | Diamonds.net, Mar. 27, 1/4p. | Africa, Guinea, Sierra Leone | News item - Stellar |
DM201505-0634 2015 | Diamonds.net | ABN Amro … diamond industry lacks bankability, not liquidity. | Diamonds.net, Mar. 27, 1/4p. | Global | News item - ABN Amro |
DM201505-0635 2015 | Diamonds.net | ABN AMRO returns to India. | Diamonds.net, Mar. 26, 1/4p. | India | News item - ABN Amro |
DM201505-0636 2015 | Diamonds.net | De Beers announces 84 sightholders. | Diamonds.net, Mar. 31, 1/4p. | Global | News item - De Beers |
DM201505-0637 2015 | Diamonds.net | Refusals exceed 30% at De Beers March sight. | Diamonds.net, Mar. 31, 1/4p. | Global | News item - De Beers |
DM201505-0638 2015 | Diamonds.net | Belgian court returns diamonds to Zimbabwe. | Diamonds.net, Mar. 31, 1/4p. | Africa, Zimbabwe, Belgium | News item - legal |
DM201505-0639 2015 | Diamonds.net | GIA's Dreams of Diamonds exhibit comes to southern California. Seven of world's finest diamond houses to showcase exceptionally rare diamonds…… | Diamonds.net, Apr. 2, 1/4p. | United States, California | News item - GIA exhibit |
DM201505-0640 2015 | Diamonds.net | Zimbabwe's Vice President Mnangagwa colluded with the army and Chinese .. Accused of stealing diamonds. | Diamonds.net, Apr. 1, 1/4p. | Africa, Zimbabwe | News item - legal |
DM201505-0641 2015 | Diamonds.net | Production drops over refinancing difficulty in 2014. | Diamonds.net, Apr. 1, 1/4p. | Russia, Yakutia | News item - Alrosa |
DM201505-0642 2015 | Diamonds.net | Mugabe taps reserve bank to stop diamond smuggling. | Diamonds.net, Apr. 4, 1/4p. | Africa, Zimbabwe | News item - legal |
DM201505-0643 2015 | Diamonds.net | Contrasting quarters … 2014 and 2015. Cause and effect. | Diamonds.net, Apr. 4, 1p. | Global | News item - prices |
DM201505-0644 2015 | Diamonds.net | Chidhakwa faces pressure to deliver diamond royalties. | Diamonds.net, Apr. 9, 1/4p. | Africa, Zimbabwe | News item - legal |
DM201505-0645 2015 | Diamonds.net | Lucapa recovers a 63 ct diamond from Lulo. | Diamonds.net, Apr. 17, 1/4p. | Africa, Angola | News item - Lucapa |
DM201505-0646 2015 | Diamonds.net | Petra's revenue - 41% to $ 96 m in 3 Q. | Diamonds.net, Apr. 16, 1/4p. | Africa, South Africa | News item - Petra |
DM201505-0647 2015 | Diamonds.net | Severalmaz appoints Pismenny as CEO. | Diamonds.net, Apr. 16, 1/4p. | Russia, Kola Peninsula, Archangel | News item - Severalmaz |
DM201505-0648 2015 | Diamonds.net | Diamcor's rough sale achieves $ 842 K ( Krone-Endora) | Diamonds.net, Apr. 15, 1/4p. | Africa, South Africa | News item - Diamcor |
DM201505-0649 2015 | Diamonds.net | NGOs urge Zimbabwe to consult with stakeholders in Marange merger. | Diamonds.net, Apr. 15, 1/4p. | Africa, Zimbabwe | News item - legal |
DM201505-0650 2015 | Diamonds.net | OGI debuts symmetry leakage technology. | Diamonds.net, Apr. 20, 1/4p. | Technology | News item - OGI |
DM201505-0651 2015 | Diamonds.net | Investigators probe Marange diamond firm Ji nan for transferring $ 546 million. | Diamonds.net, Apr. 17, 1/4p. | Africa, Zimbabwe | News item - Jinan |
DM201505-0652 2015 | Diamonds.net | Lucapa's third sale of Lulo production achieves $ 790K. | Diamonds.net, Apr. 22, 1/4p. | Africa, Angola | News item - Lucapa |
DM201505-0653 2015 | Diamonds.net | Alrosa's first quarter diamond production + 14%. | Diamonds.net, Apr. 21, 1/4p. | Russia | News item - Alrosa |
DM201506-0654 2015 | Diamonds.net | Petra Diamonds launches $300 miln notes issue to fund Culli nan construction. | Diamonds.net, Apr. 24, 1/4p. | Africa, South Africa | News item - Petra |
DM201506-0655 2015 | Diamonds.net | Zimbabwe diamond centre to open in phases ( machinery sourced from India). | Diamonds.net, Apr. 24, 1/4p. | Africa, Zimbabwe | News item - Diamond Centre |
DM201506-0656 2015 | Diamonds.net | Residents fear consolidation releases Marange firms from broken promises. | Diamonds.net, Apr. 23, 1/4p. | Africa, Zimbabwe | News item - Marange |
DM201506-0657 2015 | Diamonds.net | Bank executives tell diamond industry that risk hinders financing. | Diamonds.net, Apr. 23, 1/4p. | Global | News item - economics |
DM201506-0658 2015 | Diamonds.net | Diamcor achieves $ 5 m in revenue from Krone-Endora since 2013. | Diamonds.net, Apr. 29, 1/4p. | Africa, South Africa | News item - Diamcor |
DM201506-0659 2015 | Diamonds.net | Debmarine names new vessel after Nujoma. | Diamonds.net, Apr. 28, 1/4p. | Africa, Namibia | News item - Debmarine |
DM201506-0660 2015 | Diamonds.net | Scio Diamond to double production levels. | Diamonds.net, Apr. 27, 1/4p. | Technology | News item - Scio |
DM201506-0661 2015 | Diamonds.net | Lace mine to ramp up production in second half of 2015. | Diamonds.net, Apr. 30, 1/4p. | Africa, South Africa | News item - DiamondCorp |
DM201506-0662 2015 | Diamonds.net | Disciplined diamantaires …. | Diamonds.net, May 1, 1/4p. | Global | News item - legal |
DM201506-0663 2015 | Diamonds.net | Zimbabwe's local cutters face total lack of supply. | Diamonds.net, May 7, 1/4p. | Africa, Zimbabwe | News item - cutting |
DM201506-0664 2015 | Diamonds.net | Unchecked private jets deliver Marange diamonds to Dubai, Hong Kong. | Diamonds.net, May 6, 1/4p. | Africa, Zimbabwe | News item - Marange |
DM201506-0665 2015 | Diamonds.net | Market correction: diamond markets under pressure. Martin Rapaport discussion. | Diamonds.net, May 8, 8p. | Global | News item - prices and markets |
DM201506-0666 2015 | Diamonds.net | Lucara's revenue -10%, profit +18% in 1Q. Karowe | Diamonds.net, May 12, 1/4p. | Africa, Botswana | News item - Lucara |
DM201506-0667 2015 | Diamonds.net | Victor mine's royalties total $ 226 for the 2013 and 2014 period. | Diamonds.net, May 12, 1/4p. | Canada, Ontario | News item - De Beers |
DM201506-0668 2015 | Diamonds.net | Zimbabwe's production value -23% in 2014 to $ 350 million -Marange | Diamonds.net, May 15, 1/4p. | Africa, Zimbabwe | News item - economics |
DM201506-0669 2015 | Diamonds.net | Zimbabwe's green diamonds remain a risk for U.S. traders. | Diamonds.net, May 13, 1/4p. | Africa, Zimbabwe | News item - KP |
DM201506-0670 2015 | Diamonds.net | Zimbabwe's diamond mining consolidation plan in limbo. | Diamonds.net, May 18, 1/4p. | Africa, Zimbabwe | News item - legal |
DM201506-0671 2015 | Diamonds.net | U.S. reiterates rough diamond suspension on Venezuela, CAR. | Diamonds.net, May 18, 1/4p. | Africa, Central African Republic, South America, Venezuela | News item - KP |
DM201506-0672 2015 | Diamonds.net | Shore Gold to raise $ 2 mill in private placement. Orion | Diamonds.net, May 20, 1/4p. | Canada, Saskatchewan | News item - Shore Gold |
DM201506-0673 2015 | Diamonds.net | Lucapa's fourth parcel sale from Lulo generates $ 2m. | Diamonds.net, May 19, 1/4p. | Africa, Angola | News item - Lucapa |
DM201506-0674 2015 | Diamonds.net | Dominion Diamonds's 1 Q rough diamond sales+ 7%. | Diamonds.net, May 22, 1/4p. | Canada, Northwest Territories | News item - Dominion |
DM201507-0675 2015 | Diamonds.net | IGI certifies 10 carat diamond grown with new technology. ( New Diamond Technology lab Russia fashioned from 32.36 carat man made rough) | Diamonds.net, May 26, 1/4p. | Technology | News item - New Diamond Technology LLC |
DM201507-0676 2015 | Diamonds.net | Stellar Diamonds achieved $ 505,000 from its recent sale of rough diamonds from the Baoule project in Guinea. | Diamonds.net, May 28, 1/4p. | Africa, Guinea | News item - Stellar |
DM201507-0677 2015 | Diamonds.net | Phillippe Mellier's speech transcript from JCK talks series. | Diamonds.net, May 30, 1/4p. | Global | News item - De Beers |
DM201507-0678 2015 | Diamonds.net | De Beers re-launch 'A diamond is forever' campaign. | Diamonds.net, May 29, 1/4p. | Global | News item - De Beers |
DM201507-0679 2015 | Diamonds.net | Dominion launches CanadaMark B2B trading platform. | Diamonds.net, June 2, 1/4p. | Canada, Northwest Territories | News item - Dominion |
DM201507-0680 2015 | Diamonds.net | Okavango diamond sales volume -20% so far in 2015. | Diamonds.net, June 1, 1/4p. | Africa, Botswana | News item - Okavango |
DM201507-0681 2015 | Diamonds.net | Rockwell's revenue +19%, loss widens 6%. | Diamonds.net, June 1, 1/4p. | Africa, South Africa | News item - Rockwell |
DM201507-0682 2015 | Diamonds.net | Diamond Corp raises $ 5 m., proposes another $ 3 m 'open offer' placement. Lace | Diamonds.net, June 5, 3p. | Africa, South Africa | News item - DamondCorp |
DM201507-0683 2015 | Diamonds.net | Lucapa ramping up Angola alluvial production, kimberlite exploration. | Diamonds.net, June 5, 1/4p. | Africa, Angola | News item - Lucapa |
DM201507-0684 2015 | Diamonds.net | Trans Hex Group FY revenue +35%, profit soars. | Diamonds.net, June 4, 1/4p. | Africa, South Africa | News item - Trans Hex |
DM201507-0685 2015 | Diamonds.net | Weak ruble boosts Alrosa revenue, profit in 1 Q. | Diamonds.net, June 4, 1/4p. | Russia | News Item - Alrosa |
DM201507-0686 2015 | Diamonds.net | Illegal rough trade flourishes despite CAR's embargo. | Diamonds.net, June 8, 1/4p. | Africa, Central African Republic | News item - legal |
DM201507-0687 2015 | Diamonds.net | AWDC, diamond admin. Of Chin a sign cooperative agreement. | Diamonds.net, June 4, 1/4p. | China, Belgium | News item - AWDC |
DM201507-0688 2015 | Diamonds.net | Confidence in the diamond dream. Forevermark | Diamonds.net, June 12, 1/4p. | Global | News item - De Beers |
DM201507-0689 2015 | Diamonds.net | Mustang Resources recovers diamonds in Mozambique. | Diamonds.net, June 16, 1/2p. | Africa, Mozambique | News item - Mustang |
DM201507-0690 2015 | Diamonds.net | Israel's diamond leaders call for reduced rough supply. | Diamonds.net, June 16, 1/4p. | Global | News item - IDE |
DM201507-0691 2015 | Diamonds.net | Diamonds provide ample funding to warlords in CAR. | Diamonds.net, June 18, 1/4p. | Africa, Central African Republic | News item - legal |
DM201507-0692 2015 | Diamonds.net | De Beers June sight estimated at $ 550 million. | Diamonds.net, June 18, 1/4p. | Global | News item - De Beers |
DM201507-0693 2015 | Diamonds.net | Shore Gold completes drilling program at Star-Orion South. | Diamonds.net, June 17, 1/4p. | Canada, Saskatchewan | News item - Shore |
DM201507-0694 2015 | Diamonds.net | Zimbabwe turns to Botswana for better managing diamonds. | Diamonds.net, June 19, 1/4p. | Africa, Zimbabwe, Botswana | News item - legal |
DM201507-0695 2015 | Diamonds.net | Paragon preps share buyback, seeks immediate Mothae acquisition. | Diamonds.net, June 19, 1/4p. | Africa, Lesotho | News item - Paragon |
DM201507-0696 2015 | Diamonds.net | Demand grows for industrial and synthetic diamonds. | Diamonds.net, June 19, 1/4p. | Technology | News item - industrial diamonds |
DM201507-0697 2015 | Diamonds.net | Diamond trade subject to arbitration on color grading standards. Policy sets guidelines to tolerance levels on grading. | Diamonds.net, June 21, 1/4p. | Technology | News item - grading |
DM201507-0698 2015 | Diamonds.net | Namibia reviews terms of venture with De Beers. | Diamonds.net, June 22, 1/4p. | Africa, Namibia | News item - De Beers |
DM201507-0699 2015 | Diamonds.net | Kennedy Diamonds reports sample grade from Kelvin winter drill program. | Diamonds.net, June 22, 1/4p. | Canada, Northwest Territories | News item - Kennady |
DM201507-0700 2015 | Diamonds.net | London Bourse members gain access to bonded warehouse. | Diamonds.net, June 24, 1/4p. | Europe, England | News item - bourse |
DM201507-0701 2015 | Diamonds.net | OGI releases Titanium 5X laser cutting system. | Diamonds.net, June 23, 1/4p. | Technology | News item - OGI |
DM201507-0702 2015 | Diamonds.net | Alrosa repays $ 185 m worth of commercial bonds. | Diamonds.net, June 23, 1/4p. | Russia | News item - Alrosa |
DM201507-0703 2015 | Diamonds.net | KP leaders stress consensus and bringing CAR, Venezuela back into compliance. | Diamonds.net, June 24, 1/4p. | Africa, Central African Republic, South America, Venezuela | News item - KP |
DM201507-0704 2015 | Diamonds.net | Mellier says Namibia's new diamond sales terms are satisfactory. | Diamonds.net, June 24, 1/4p. | Africa, Namibia | News item - De Beers |
DM201508-0705 2015 | Diamonds.net | Rapaport presents industry insights, Lussier explains 'The Diamond Dream'. | Diamonds.net, June 25, 1/4p. | Global | News item - economics |
DM201508-0706 2015 | Diamonds.net | Namdeb CEO leaves post for government position. Inge Zaamwani-Kamwi | Diamonds.net, July 1, 1/4p. | Africa, Namibia | News item - Namdeb |
DM201508-0707 2015 | Diamonds.net | Kimberley Process presents roadmap for CAR compliance. | Diamonds.net, June 30, 1p. | Africa, Central African Republic | News item - KP |
DM201508-0708 2015 | Diamonds.net | Paragon Diamonds loss widens, Revenue target for 2015 is $ 36 million. | Diamonds.net, June 29, 1/4p. | Africa, Lesotho | News item - Paragon |
DM201508-0709 2015 | Diamonds.net | Large size diamond market under pressure. Q&A with Amir Tiroche, owner and CEO of Tiroche Diamonds. | Diamonds.net, July 3, 1/4p. | Global | News item - Tiroche |
DM201508-0710 2015 | Diamonds.net | Diamond storytelling… marketing and "A Diamond is Forever". | Diamonds.net, July 3, 2p. | Global | News item - De Beers |
DM201508-0711 2015 | Diamonds.net | India to continue importing rough diamonds for now. | Diamonds.net, July 7, 1/4p. | India | News item - rough |
DM201508-0712 2015 | Diamonds.net | Zimbabwe mulls bid for Kimberley Process chairmanship by 2018. | Diamonds.net, July 7, 1/4p. | Africa, Zimbabwe | News item - KP |
DM201508-0713 2015 | Diamonds.net | Scio revenue halves, loss narrows to $ 4 million. | Diamonds.net, July 6, 1/4p. | Technology | News item - Scio |
DM201508-0714 2015 | Diamonds.net | Botswana's Okavango diamond sales fell 23% in 1 H | Diamonds.net, July 9, 1/4p. | Africa, Botswana | News item - Okavango |
DM201508-0715 2015 | Diamonds.net | Sightholders can defer 25% of De Beers July supply. | Diamonds.net, July 9, 1p. | Global | News item - De Beers |
DM201508-0716 2015 | Diamonds.net | HRD discovers hard-to-detect synthetic rough diamonds: quick take. | Diamonds.net, July 13, 1/4p. | Technology | News item - HRD Lab |
DM201508-0717 2015 | Diamonds.net | Diamond Hallmarketing seeks to make its mark. | Diamonds.net, July 17, 2p. | Global | News item - Hallmarking |
DM201508-0718 2015 | Diamonds.net | Peregrine Diamonds begins summer development program at Chidliak. | Diamonds.net, July 21, 1/4p. | Canada, Nunavut, Baffin Island | News item - Peregrine |
DM201508-0719 2015 | Diamonds.net | Namibia to introduce independent rough diamond sales. | Diamonds.net, July 21, 1/4p. | Africa, Namibia | News item - De Beers |
DM201508-0720 2015 | Diamonds.net | Alrosa's 1 H rough diamond sales drop 22 %: quick take. | Diamonds.net, July 21, 1/4p. | Russia | News item - Alrosa |
DM201508-0721 2015 | Diamonds.net | Diamcor generates sales of $ 455K in 1 Q. Krone-Endora | Diamonds.net, July 20, 1/4p. | Africa, South Africa | News item - Diamcor |
DM201508-0722 2015 | Diamonds.net | Villagers confront EMA Board about diamond mining pollution. | Diamonds.net, July 20, 1/4p. | Africa, Zimbabwe | News item - EMA |
DM201508-0723 2015 | Diamonds.net | Seeking a better diamond future. Comments from Lieberherr Rio Tinto Diamonds. | Diamonds.net, July 17, 1p. | Global | News item - Rio Tinto |
DM201508-0724 2015 | Diamonds.net | New synthetic detector to be shown at HK September show: Quick Take | Diamonds.net, July 22, 1/4p. | Technology | News item - Diamond Services |
DM201508-0725 2015 | Diamonds.net | Surat diamond bourse project put on hold. | Diamonds.net, July 22, 1/4p. | India | News item - Surat |
DM201508-0726 2015 | Diamonds.net | Mbada's security guards unleash dogs on illegal panners. | Diamonds.net, July 24, 1/4p. | Africa, Zimbabwe | News item - Mbada |
DM201508-0727 2015 | Diamonds.net | The futility of chasing rough shadows. | Diamonds.net, July 24, 1/4p. | Global | News item - De Beers |
DM201508-0728 2015 | Diamonds.net | Alrosa has shifted operations at the iconic Udachnay mine…. Opened in June 1955 ..Alrosa's Largest open pit 1,600 X 2,000 m and depth 640 m. 350 million tons of ore containing $ 80 Billion worth mined diamonds. | Diamonds.net, July 27, 1/4p. | Russia, Yakutia | News item - Alrosa |
DM201509-0729 2015 | Diamonds.net | Unique volcano diamonds found in Russian Far East. Tolbachik | Diamonds.net, July 27, 1/4p. | Russia, Kamchatka | News item - Tolbachik |
DM201509-0730 2015 | Diamonds.net | Gem Diamonds 1 H revenue falls 28%. | Diamonds.net, July 30, 1/4p. | Africa, Lesotho, Botswana | News item - Gem Diamonds |
DM201509-0731 2015 | Diamonds.net | Fipke joins Dunnedin Ventures as company advisor. Kahuna | Diamonds.net, July 30, 1/4p. | Canada, Nunavut | News item - Dunnedin |
DM201509-0732 2015 | Diamonds.net | Gokhran's rough auction achieves $ 479 per carat. | Diamonds.net, July 30, 1/4p. | Russia | News item - Gokhran |
DM201509-0733 2015 | Diamonds.net | Zimbabwe to consolidate Marange miners by end of 2015 ( seven companies) | Diamonds.net, July 29, 1/4p. | Africa, Zimbabwe | News item - Marange |
DM201509-0734 2015 | Diamonds.net | Russia weighs establishing rough diamond exchange. | Diamonds.net, July 29, 1/4p. | Russia | News item - bourse |
DM201509-0735 2015 | Diamonds.net | Lucapa raises $ 3 million for Lulo, postpones rough sale. | Diamonds.net, July 27, 1/4p. | Africa, Angola | News item - Lucapa |
DM201509-0736 2015 | Diamonds.net | Kao mine large diamond tender begins in New York. | Diamonds.net, Aug. 3, 1/4p. | Africa, Lesotho | News item - Namakwa, Storm Mountain, Fusion, I Hennig |
DM201509-0737 2015 | Diamonds.net | Gem International Resources seeks stake in Angola's Dala diamond concession. | Diamonds.net, Aug. 3, 1/4p. | Africa, Angola | News item - Gem Diamonds |
DM201509-0738 2015 | Diamonds.net | State Diamond Trader seeks partners for growth. | Diamonds.net, July 31, 1/4p. | Africa, South Africa | News item - State Diamond Trader |
DM201509-0739 2015 | Diamonds.net | Ellendale mine worker accuses Kimberley Diamonds of unsafe practices. | Diamonds.net, Aug. 5, 1/4p. | Australia | News item - Kimberley Diamonds |
DM201509-0740 2015 | Diamonds.net | Rio Tinto diamond revenue -23% to $ 331 million in H1. | Diamonds.net, Aug. 6, 1/4p. | Global | News item - Rio Tinto |
DM201509-0741 2015 | Diamonds.net | Lucara cuts production outlook as 2Q revenue, profit plummet. Karowe | Diamonds.net, Aug. 13, 1/4p. | Africa, Botswana | News item - Lucara |
DM201509-0742 2015 | Diamonds.net | Botswana diamond producers cut 1,000 jobs in past year. Mmegi | Diamonds.net, Aug, 13, 1/4p. | Africa, Botswana | News item - cutters |
DM201509-0743 2015 | Diamonds.net | Weak diamond sales may fuel Botswana budget deficit. | Diamonds.net, Aug. 18, 1/4p. | Africa, Botswana | News item - sales |
DM201509-0744 2015 | Diamonds.net | Lucara finds 336 carat diamond at Botswana mine. Karowe | Diamonds.net, Aug. 18, 1/4p. | Africa, Botswana | News item - Lucara |
DM201509-0745 2015 | Diamonds.net | Namibia diamond venture pays % 4.6 m dividend to state. NDTC | Diamonds.net, Aug. 19, 1/4p. | Africa, Namibia | News item - NDTC |
DM201509-0746 2015 | Diamonds.net | Is diamond demand determined in Beijing and Washington? | Diamonds.net, Aug. 20, 1/4p. | United States, China | News item - demand |
DM201509-0747 2015 | Diamonds.net | Russia outshines Botswana as world's top diamond producer in 2014. | Diamonds.net, Aug. 25, 1/4p. | Russia | News item - Alrosa |
DM201509-0748 2015 | Diamonds.net | Stellar says Tongo to produce 1 million carats over 18 years. | Diamonds.net, Aug. 24, 1/4p. | Africa, Sierra Leone | News item - Stellar |
DM201509-0749 2015 | Diamonds.net | De Beers price cuts could top 10% at sight. | Diamonds.net, Aug. 25, 1/4p. | Global | News item - De Beers |
DM201509-0750 2015 | Diamonds.net | Blue diamonds drive color index higher in 2Q. Fancy Color diamond index ( FCDI tm) | Diamonds.net, Aug. 25, 1/4p. | Global | News item - Blue diamonds |
DM201509-0751 2015 | Diamonds.net | Sightholders react to price cuts at $250M sight…. Mixed reactions. | Diamonds.net, Aug. 27, 1/4p. | Global | News item - De Beers |
DM201509-0752 2015 | Diamonds.net | De Beers maintains outlook for season amid market turmoil. | Diamonds.net, Aug. 26, 1/4p. | Global | News item - De Beers |
DM201510-2016 2015 | Diamonds.net | GIA plans 2016 for opening for synthetic research centre. | Diamonds.net, Sept. 1, 1/4p. | United States, New Jersey | News item - GIA |
DM201510-2017 2015 | Diamonds.net | Alrosa 1 Q sales up 20% $875.8 million. | Diamonds.net, Aug. 30, 1/4p. | Russia | News item - Alrosa |
DM201510-2018 2015 | Diamonds.net | Alrosa unit diamonds go missing at Gokhran. | Diamonds.net, Aug. 30, 1/4p. | Russia | News item - Alrosa |
DM201510-2019 2015 | Diamonds.net | Alrosa may cut diamond prices again as orders fall short. | Diamonds.net, Sept. 2, 1/4p. | Russia | News item - Alrosa |
DM201510-2020 2015 | Diamonds.net | Lucapa recovers 10 ct plus diamonds from Angola's Lulo site. | Diamonds.net, Sept. 3, 1/4p. | Africa, Angola | News item - Lucapa |
DM201510-2021 2015 | Diamonds.net | Mwana Africa to raise $ 5.6 million for Klipspringer mine work. | Diamonds.net, Sept. 3, 1/4p. | Africa, South Africa | News item - Mwana |
DM201510-2022 2015 | Diamonds.net | New sightholder KGK opens Botswana factory. | Diamonds.net, Sept. 3, 1/4p. | Africa, Botswana | News item - KGK |
DM201510-2023 2015 | Diamonds.net | Zimbabwe urged to curb rough diamond exports. | Diamonds.net, Sept. 6, 1/4p. | Africa, Zimbabwe | News item - exports |
DM201510-2024 2015 | Diamonds.net | Russia looks to Shanghai experience for Vladivostok diamond exchange. | Diamonds.net, Sept. 6, 1/4p. | Russia | News item - Vladivostok |
DM201510-2025 2015 | Diamonds.net | Lucara sets November exceptional stone tender. Karowe | Diamonds.net, Sept. 8, 1/4p. | Africa, Botswana | News item - Lucara |
DM201510-2026 2015 | Diamonds.net | Israel diamond industry readies for anti-money laundering law. | Diamonds.net, Sept. 9, 1/4p. | Europe, Israel | News item - legal |
DM201510-2027 2015 | Diamonds.net | Diamond prices pressured by financial market slump. | Diamonds.net, Sept. 9, 1/4p. | Global | News item - prices, supply, demand |
DM201510-2028 2015 | Diamonds.net | Catoca mine diamond sales rise 1% in 2014. | Diamonds.net, Sept. 9, 1/4p. | Africa, Angola | News item - Endiama |
DM201510-2029 2015 | Diamonds.net | Kimberley process: where is it now? | Diamonds.net, Sept. 9, 2p. | Global | News item - KP |
DM201510-2030 2015 | Diamonds.net | Ex-Kimberley Diamonds boss arrested over yellow diamond price reports. Alexander Alexander | Diamonds.net, Sept. 16, 1/4p. | Australia | News item - Kimberley Diamonds |
DM201510-2031 2015 | Diamonds.net | De Beers growth highlights India as counter to flat growth. | Diamonds.net, Sept. 21, 1/4p. | India | News item - De Beers |
DM201510-2032 2015 | Diamonds.net | Botswana and Alrosa start Orapa license work. | Diamonds.net, Sept. 21, 1/4p. | Africa, Botswana | New item - Botswana Diamonds, Alrosa |
DM201510-2033 2015 | Diamonds.net | Russia's H1 rough diamond exports slide 16%. | Diamonds.net, Sept. 20, 1/4p. | Russia | News item - Alrosa |
DM201511-2124 2015 | Diamonds.net | Rio Tinto sets first time India rough auction. | Diamonds.net, Sept. 29, 1/4p. | India | News item - Rio Tinto |
DM201511-2125 2015 | Diamonds.net | Lab grown diamonds set to fill deficit as mined output declines. | Diamonds.net, Sept. 29, 1/4p. | Global | News item - synthetics |
DM201511-2126 2015 | Diamonds.net | Fancy vivid pink diamond to list at Christies for $ 23-28 million. 16.08 cts | Diamonds.net, Sept. 29, 1/4p. | Global | News item - diamond notable |
DM201511-2127 2015 | Diamonds.net | India preparing measures to raise direct purchases of Russian rough. | Diamonds.net, Sept. 29, 1/4p. | Russia, India | News item - rough |
DM201511-2128 2015 | Diamonds.net | Indian diamond consumers need differentiated strategy: De Beers. | Diamonds.net, Sept. 29, 1/4p. | India | News item - De Beers |
DM201511-2129 2015 | Diamonds.net | Botswana first half rough exports - 15% | Diamonds.net, Oct. 1, 1/4p. | Africa, Botswana | News item - Debswana |
DM201511-2130 2015 | Diamonds.net | Alrosa unearths 103 carat diamond at Jubilee pipe. | Diamonds.net, Oct. 12, 1/4p. | Russia | News item - Alrosa |
DM201511-2131 2015 | Diamonds.net | De Beers October rough sales reflect depressed market. | Diamonds.net, Oct. 14, 1/4p. | Global | News item - De Beers |
DM201511-2132 2015 | Diamonds.net | Diamond Corp delays sales due to slow mining progress. Lace | Diamonds.net, Oct. 15, 1/4p. | Africa, South Africa | News item - DiamondCorp |
DM201511-2133 2015 | Diamonds.net | Synthetic diamonds: legitimize, don't ostracize. | Diamonds.net, Oct. 15, 2p. | Technology | News item - synthetics |
DM201511-2134 2015 | Diamonds.net | Ellendale may be handed back to the local government. | Diamonds.net, Oct. 22, 1/4p. | Australia | News item - Ellendale |
DM201511-2135 2015 | Diamonds.net | Signet inks rough supply deal with Alrosa. A list of Alrosa's clients included. | Diamonds.net, Oct. 21, 2p. | Russia | News item - Alrosa |
DM201511-2136 2015 | Diamonds.net | E-commerce startup Worthy raises $ 8 million for diamond, colored gems expansion. | Diamonds.net, Oct. 25, 1/2p. | Global | News item - Worthy |
DM201511-2137 2015 | Diamonds.net | GIA invalidates 1,000 plus grading reports after hackers alter data. | Diamonds.net, Oct. 24, 1/2p. | Global | News item - GIA |
DM201511-2138 2015 | Diamonds.net | De Beers enables 100% deferrals at November sight. | Diamonds.net, Oct. 26, 1/4p. | Global | News item - De Beers |
DM201512-2221 2015 | Diamonds.net | South Africa told its lagging diamond industry needs a boost. | Diamonds.net, Oct. 29, 1/4p. | Africa, South Africa | News item - economics |
DM201512-2222 2015 | Diamonds.net | Botswana 3 Q rough exports -41%. | Diamonds.net, Nov. 3, 1/4p. | Africa, Botswana | News item - exports |
DM201512-2223 2015 | Diamonds.net | Argyle pink tender results come in as Leibish wins 26 stones. | Diamonds.net, Nov. 3, 1/4p. | Australia | News item - Argyle |
DM201512-2224 2015 | Diamonds.net | Sarine Technologies swings to loss in 3Q as revenue plummets 53%. | Diamonds.net, Nov. 9, 1/4p. | Technology | News item - Sarine |
DM201512-2225 2015 | Diamonds.net | De Beers November sight slumps to estimated $ 70 million. | Diamonds.net, Nov. 11, 2p. | Global | News item - De Beers |
DM201512-2226 2015 | Diamonds.net | Rio Tinto says Karelian's FIn land find is diamond making material. | Diamonds.net, Nov. 11, 1/4p. | Europe, Finland | News item - Karelian |
DM201512-2227 2015 | Diamonds.net | Murowa mine working to boost production after Rio Tinto exit. | Diamonds.net, Nov. 11, 1/4p. | Africa, Zimbabwe | News item - Murowa Diamonds |
DM201512-2228 2015 | Diamonds.net | UK's Paragon Diamond shares, listed on UK alternative has had its shares temporarily suspended amid financial 'uncertainty'. | Diamonds.net, Nov. 17, 1/4p. | Africa, Lesotho | News item - Paragon |
DM201512-2229 2015 | Diamonds.net | Lab-grown diamond producer Scio's 2Q revenue doubles, net loss widens 8%. | Diamonds.net, Nov. 17, 1/4p. | Technology | News item - Scio |
DM201512-2230 2015 | Diamonds.net | Rio Tinto carries out first shipment of rough diamonds to BDB's special notified zone. Bharat | Diamonds.net, Nov. 16, 1/4p. | India | News item - Rio Tinto |
DM201512-2231 2015 | Diamonds.net | India's GJEPC plans advertising push with global miners to revive diamond trade. | Diamonds.net, Nov. 17, 1/4p. | India | News item - GJEPC |
DM201512-2232 2015 | Diamonds.net | Historic diamonds put Lucara in enviable spotlight. Second and Sixth largest diamonds in history. | Diamonds.net, Nov. 19, 3p. | Africa, Botswana | News item - Lucara |
DM201512-2233 2015 | Diamonds.net | Alrosa revises sales budget, keeps production plan unchanged. | Diamonds.net, Nov. 23, 1/4p. | Russia | News item - Alrosa |
DM201512-2234 2015 | Diamonds.net | De Beers shareholders to meet on diamond prices. | Diamonds.net, Nov. 23, 1/4p. | Africa, Botswana | News item - De Beers |
DM201512-2235 2015 | Diamonds.net | Dominion sales -53% as average price drop at Ekati. | Diamonds.net, Nov. 22, 1/4p. | Canada, Northwest Territories | News item - Dominion |
DM201512-2236 2015 | Diamonds.net | Australia's Mustang Resources raises $ 4.1 million to progress Mozambique projects. Save River | Diamonds.net, Nov. 25, 1/4p. | Africa, Mozambique | News item - Mustang |
DM201512-2237 2015 | Diamonds.net | Tiffany's 3Q revenue -2% as strong dollar mutes sales. | Diamonds.net, Nov. 24, 1p. | Global | News item - Tiffany |
DM201512-2238 2015 | Diamonds.net | Rapaport calls for resignation of De Beers CEO. | Diamonds.net, Nov. 24, 1/2p. | Global | News item - De Beers |
DM201512-2239 2015 | Diamonds.net | How Botswana will find independence. 50 years | Diamonds.net, Nov. 26, 1/4p. | Africa, Botswana | News item - history |
DM201512-2240 2015 | Diamonds.net | Majority of diamonds in GIA hacking case still not returned, 175 of 1,042 only so far. | Diamonds.net, Nov. 26, 1/4p. | Technology | News item - GIA |
DM201512-2241 2015 | Diamonds.net | Paragon's nominated advisor quits as London shares remain suspended. | Diamonds.net, Nov. 26, 1/4p. | Africa, Lesotho | News item - Paragon |
DM201512-2242 2015 | Diamonds.net | Zimbabwe government urged to float consolidated diamond company. | Diamonds.net, Nov. 26, 1/4p. | Africa, Zimbabwe | News item - legal |
DM201502-0540 2014 | DIB Online | Trust is a two way street…. Israel's diamond industry works to fortify local polishing sector. | Diamond Intelligence Brief, No. 844, Dec. 31, 1p. | India | News item - polishing |
DM201505-0754 2015 | DIB Online | Modular tailings plant planned for Debswana's Letlhakane mine site. | diamondintelligence.com, 1/2p. | Africa, Botswana | News item - Debswana |
DM201507-0541 2015 | DIB Online | KPCS intercessional: Zimbabwe on the agenda again. | Diamondintelligence.com, June 24, 1/4p. | Africa, Zimbabwe | News item - KP |
DM201507-0542 2015 | DIB Online | Kennady's Kelvin produces excellent results - sample grade 2.74 ct | Diamondintelligence.com, June 24, 1/4p. | Canada, Northwest Territories | News item - Kennady |
DM201507-0543 2015 | DIB Online | Sunland Minerals' Botswana exploration promising. | Diamondintelligence.com, June 18, 1/4p. | Africa, Botswana | News item - Botswana Diamonds, Alrosa |
DM201508-0755 2015 | DIB Online | De Beers mining production down 6% in Q2 | DIB Online, July 16, 1p. | Global | News item - De Beers |
DM201508-0756 2015 | DIB Online | Namibia's Trustco may acquire diamond mine and polishing factory in Namibia. Kunene Huso and NNDC | DIB Online, July 13, 1/2p. | Africa, Namibia | News item - Trustco |
DM201508-0757 2015 | DIB Online | Talks stalled between Dominion and Canada's Union of Northern Workers. | DIB Online, July 13, 1/2p. | Canada, Northwest Territories | News item - Dominion |
DM201509-0753 2015 | DIB Online | Sierra Leoneons face depletion of existing alluvial deposits. | DIB Online, Aug. 11, 1/4p. | Africa, Sierra Leone | News item - alluvials |
DM201509-0758 2015 | DIB Online | Dominion fiscal Q2 2016 results: diamond sales $ 209.7 million. Ekati and Diavik | DIBOnline.com, Aug. 23, 1/4p. | Canada, Northwest Territories | News item - Dominion |
DM201509-0759 2015 | DIB Online | Large diamond possibly worth over $ 7 million 'missing' from India's Panna district. ( shallow open pits) | DIBOnline.com, No. 861, Aug. 24, 1/4p. | India | News item - legal |
DS201512-1914 2015 | Dickson, J.S. | Rare earth elements: global market overview. | Symposium on critical and strategic materials, British Columbia Geological Survey Paper 2015-3, held Nov 13-14 2015, pp. 5-12. | Global | Rare earths |
| Abstract: Rare earth elements (REE), as defi ned by the International Union of Pure and Applied Chemistry (IUPAC), include yttrium (Y), scandium (Sc), and the lanthanides, comprising lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu). In the scientifi c community, subdivisions into light (LREE) and heavy (HREE) categories are based on electron confi guration. In this context, LREE include La, Ce, Pr, Nd, Pm, Sm, Eu, and Gd and HREE include Y, Tb, Dy, Ho, Er, Tm, Yb, and Lu (Connelly et al., 2005). Industry commonly refers to LREE as lanthanides from La to Sm, and HREE as lanthanides from Eu to Lu, plus Y (Simandl, 2014). World mine production of rare earth oxides (REO) for 2014 is estimated at approximately 117,000 tonnes, including Y2O3, which accounts for 7000 tonnes of the total (Gambogi, 2015a, b). In 2014, the main producing countries for REE less Y were China, with 86% of worldwide production (Gambogi, 2015a), the United States, India, Australia, Russia, and Thailand (Fig. 1). |
DS201502-0054 2015 | Dobretsov, N.L., Koulakov, I.Yu., Litasov, K.D., Kukarina, E.V. | An integrated model of subduction: contributions from geology, experimental petrology and seismic tomography. | Russian Geology and Geophysics, Vol. 56, 1-2, pp. 13-38. | Mantle | Subduction |
DS201509-0394 2015 | Dobretsov, N.L., Turkina, O.M. | Early Precambrian Earth history: plate and plume tectonics and extraterrestrial controls. | Russian Geology and Geophysics, Vol. 56, pp. 978-995. | Mantle | Subduction |
| Abstract: The Hadean and Archean geologic history of the Earth is discussed in the context of available knowledge from different sources: space physics and comparative planetology; isotope geochronology; geology and petrology of Archean greenstone belts (GB) and tonalite-trondhjemite-granodiorite (TTG) complexes; and geodynamic modeling review to analyse plate-tectonic, plume activity, and impact processes. Correlation between the age peaks of terrestrial Hadean-Early Archean zircons and late heavy bombardment events on the Moon, as well as the Hf isotope composition of zircons indicating their mostly mafic sources, hint to an important role of impact processes in the Earth’s history between 4.4 and 3.8 Ga. The earliest continental crust (TTG complexes) formed at 4.2 Ga (Acasta gneisses), while its large-scale recycling left imprint in Hf isotope signatures after 3.75 Ga. The associations and geochemistry of rocks suggest that Archean greenstone belts formed in settings of rifting, ocean floor spreading, subduction, and plume magmatism generally similar to the present respective processes. The Archean history differed in the greater extent of rocks derived from mantle plumes (komatiites and basalts), boninites, and adakites as well as in shorter subduction cycles recorded in alternation of typical calc-alkaline andesite-dacite-rhyolite and adakite series that were generated in a hotter mantle with more turbulent convection and unsteady subduction. The Archean is interpreted as a transient period of small plate tectonics. |
DS201507-0309 2015 | Dobretsov, N.L., Zedgenizov, D.A., Litasov, K.D. | Evidence for and consequences of the "hot" subduction model. | Doklady Earth Sciences, Vol. 461, 1, pp. 517-521. | Mantle | Subduction |
DS201511-1832 2015 | Doglioni, C., Anderson, D.L. | Top-driven asymmetric mantle convection. | Geological Society of America Special Paper, No. 514, pp. SPE514-05. | Mantle | Convection |
| Abstract: The role of decoupling in the low-velocity zone is crucial for understanding plate tectonics and mantle convection. Mantle convection models fail to integrate plate kinematics and thermodynamics of the mantle. In a first gross estimate, we computed at >300 km3/yr the volume of the plates lost along subduction zones. Mass balance predicts that slabs are compensated by broad passive upwellings beneath oceans and continents, passively emerging at oceanic ridges and backarc basins. These may correspond to the broad low-wavespeed regions found in the upper mantle by tomography. However, west-directed slabs enter the mantle more than three times faster (?232 km3/yr) than in the opposite east- or northeast-directed subduction zones (?74 km3/yr). This difference is consistent with the westward drift of the outer shell relative to the underlying mantle, which accounts for the steep dip of west-directed slabs, the asymmetry between flanks of oceanic ridges, and the directions of ridge migration. The larger recycling volumes along west-directed subduction zones imply asymmetric cooling of the underlying mantle and that there is an "easterly" directed component of the upwelling replacement mantle. In this model, mantle convection is tuned by polarized decoupling of the advecting and shearing upper boundary layer. Return mantle flow can result from passive volume balance rather than only by thermal buoyancy-driven upwelling. |
DC201501-1457 2014 | Dolat Ventures Inc. | Dolat Ventures Inc. completes corporate restructuring…and Millenium Mining LLC ( subsidiary) has signed a JV to restart diamond mining near Bo, Sierra Leone. Sewa River | Dolat Ventures Inc., Dec. 1, 1p. | Africa, Sierra Leone | News item - press release |
DC201501-1458 2014 | Dolat Ventures Inc. | Moves forward with private investment into diamond mine assets. To restart mining at Bo, Sierra Leone. | Dolat Ventures Inc., Dec. 9, 1p. | Africa, Sierra Leone | News item - press release |
DC201501-1459 2014 | Dolat Ventures Inc. | Dolat ventures to reduce outstanding stock. | Dolat Ventures Inc., Dec. 12, 1p. | Africa, Sierra Leone | News item - press release |
DC201503-1460 2015 | Dominion Diamond Corporation | Dominion Diamond Corporation announces Jay project pre-feasibility study results. 84.6 million carats promoted to mineral reserve… NPV of $ 610 mililon. | Dominion Diamond Corporation, Jan. 28, 3p. | Canada, Northwest Territories | News item - press release |
DC201503-1461 2015 | Dominion Diamond Corporation | Dominon Diamond reports fiscal 2015 fourth quarter and year end sales and production results. | Dominion Diamond Corporation, Feb. 23, 5p. | Canada, Northwest Territories | News item - press release |
DC201504-1462 2015 | Dominion Diamond Corporation | Dominion Diamond Corporation issues updated reserves amd resources statement for the Diavik diamond mine. | Dominion Diamond Corporation, Mar. 6, 5p. | Canada, Northwest Territories | News item - press release |
DC201504-1463 2015 | Dominion Diamond Corporation | Dominion files technical report for the Ekati diamond mine. | Dominion Diamond Corporation, Mar. 12, 14p. | Canada, Northwest Territories | News item - press release |
DC201505-1464 2015 | Dominion Diamond Corporation | Dominion Diamond Corporation files technical report for the Diavik diamond mines. | Dominion Diamond Corporation , Mar. 26, 2p. | Canada, Northwest Territories | News item - press release |
DC201505-1465 2015 | Dominion Diamond Corporation | Dominion Diamond Corporation reports continued strong operating results supporting dividend declaration. | Dominion Diamond Corporation , Apr. 8, 4p. | Canada, Northwest Territories | News item - press release |
DC201505-1466 2015 | Dominion Diamond Corporation | Dominion Diamond Corporation files annual report on Form 40-F with SEC. | Dominion Diamond Corporation , Apr. 20, 2p.. | Canada, Northwest Territories | News item - press release |
DC201505-1467 2015 | Dominion Diamond Corporation | Dominion reports Diavik diamond mine first calendar quarter production. | Dominion Diamond Corporation , Apr. 21, 5p. | Canada, Northwest Territories | News item - press release |
DC201506-1468 2015 | Dominion Diamond Corporation | Dominion Diamond Corporation reports fiscal 2016 first quarter sales and production results. | Dominion Diamond Corporation, May 21, 5p. | Canada, Northwest Territories | News item - press release |
DC201507-1469 2015 | Dominion Diamond Corporation | Dominion Diamond Corporation's fiscal 2016 first quarter results to be released Wednesday June 10, 2015. | Dominion Diamond Corporation, June 10, 3p. | Canada, Northwest Territories | News item - press release |
DC201508-1470 2015 | Dominion Diamond Corporation | Dominion Diamond Corporation announces Chairman Robert A. Gannicott to resume duties and Brendan Bell appointed CEO. | Dominion Diamond Corporation, July 13, 1p. | Canada, Northwest Territories | News item - press release |
DC201508-1471 2015 | Dominion Diamond Corporation | Dominion Diamond Corporation reports Diavik diamond mine second calendar quarter production. | Dominion Diamond Corporation, July 15, 2p. | Canada, Northwest Territories | News item - press release |
DC201509-1472 2015 | Dominion Diamond Corporation | Dominion Diamond Corporation fiscal 2016 second quarter sales and production results. | Dominion Diamond Corporation, Aug. 20, 5p. | Canada, Northwest Territories | News item - press release |
DC201510-2344 2015 | Dominion Diamond Corporation | Dominion Diamond Corporation reports fiscal 2016 second quarter results. | Dominion Diamond Corporation, Sept. 10, 5p. | Canada, Northwest Territories | News item - press release |
DC201510-2345 2015 | Dominion Diamond Corporation | Dominion Diamond Corporation announces Sable project preliminary economic assessment results. 11.7 m carats operational synergies with Jay project. | Dominion Diamond Corporation, Sept. 10, 2p. | Canada, Northwest Territories | News item - press release |
DC201511-2378 2015 | Dominion Diamond Corporation | Dominion Diamond Corporation reports Diavik diamond mine third calendar quarter production. | Dominion Diamond Corporation, Oct. 15, 7p. | Canada, Northwest Territories | News item - press release |
DC201512-2430 2015 | Dominion Diamond Corporation | Dominion Diamond reports fiscal 2016 third quarter sales and production results. | Dominion Diamond Corporation, Nov. 20, 5p. | Canada, Northwest Territories | News item - press release |
DS201508-0350 2015 | 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. | India | Deposit - Wajrakarur |
DS201508-0351 2015 | Dongre, A.N., Viljoen, K.S., Ma, M. | The Pipe-15 kimberlite: a new addition to the Wajrakarur cluster of the Wajrakarur kimberlite field, Eastern Dharwar craton, southern India. | Journal of the Geological Society of India, Vol. 86, 1, pp. 71-79. | India | Deposit - Pipe-15 |
DS201502-0055 2015 | Dorogokupets, P.I., Dymshits, A.M., Sokolova, T.S., Danilov, B.S., Litasov, K.D. | The equations of state of forsterite, wadsleyite, ringwoodite, akimotoite, Mg2SiO4 perovskite and post perovskite and phase diagram for the Mg2SiO4 system at pressures of up to 130 Gpa. | Russian Geology and Geophysics, Vol. 56, 1-2, pp. 172-189. | Technology | Perovskite |
DS201511-1833 2014 | Downes, P.J., Bevan, A.W.R., Deacon, G.L. | The Kimberley Diamond Company Ellendale diamond collection at the Western Australia Museum. | Australian Gemmologist, Vol. 24, 12, pp. 289-293. | Australia | Deposit - Ellendale |
DC201502-1474 2015 | Dunnedin Ventures Inc. | TSX venture exchange approves Kahuna option agreement. | Dunnedin Ventures Inc., Jan. 5, 1p. | Canada, Nunavut | News item - press release |
DC201503-1473 2015 | Dunnedin Ventures Inc. | Dunnedin reports 4.02 carat inferred diamond resource at Khuna. | Dunnedin Ventures Inc., Jan. 26, 3p. | Canada, Nunavut | News item - press release |
DC201504-1475 2015 | Dunnedin Ventures Inc. | Dunnedin increases land position to control additional kimberlites. Kahuna | Dunnedin Ventures Inc., Mar. 2, 1p. | Canada, Nunavut | News item - press release |
DC201505-1476 2015 | Dunnedin Ventures Inc. | Dunnedin files maiden resource report including additional target for further exploration. Kahuna and Notch | Dunnedin Ventures Inc., Mar. 31, 1p. | Canada, Nunavut | News item - press release |
DC201506-1477 2015 | Dunnedin Ventures Inc. | Dunnedin receives land use permits and adds diamond project development expertise. Kahuna | Dunnedin Ventures Inc., May 7, 1p. | Canada, Nunavut | News item - press release |
DC201508-1478 2015 | Dunnedin Ventures Inc. | Dunnedin announces July mobiliazation and expands scope of project. Kahuna | Dunnedin Ventures Inc., June 29, 2p. | Canada, Nunavut, Rankin Inlet | News item - press release |
DC201510-2346 2015 | Dunnedin Ventures Inc. | Dunnedin provides update on summer diamond exploration and announces non-brokered private placement. | Dunnedin Ventures Inc., Aug. 31, 1p. | Canada, Nunavut | News item - press release |
DC201511-2379 2015 | Dunnedin Ventures Inc. | Dunnedin provides update on kimberlite sample processing. Kahuna and Notch. | Dunnedin Ventures Inc., Oct. 8, 1p. | Canada, Nunavut | News item - press release |
DC201512-2431 2015 | Dunnedin Ventures Inc. | Dunnedin reports 5.34 carats from first 0.82 tonne kimberlite sample. | Dunnedin Ventures Inc., Nov. 12, 1p. | Canada, Quebec | News item - press release |
DC201505-1479 2015 | Durango Resources Inc. | Durango signs non binding LOI for diamonds in James Bay. | Durango Resources Inc., Mar. 24, 1p. | Canada, Quebec, Otish Mountains | News item - press release |
DC201505-1480 2015 | Durango Resources Inc. | Durango to focus on gold in the James Bay region. Not to continue LOI for the Lucky 7 diamond property. | Durango Resources Inc., Apr. 1, 1p. | Canada, Quebec | News item - press release |
DS201504-0193 2014 | Dvoichenkova, G.P. | Mineral formations on natural diamond surface and their destruction using electrochemically modified mineralized water. | Journal of Mining Science, Vol. 50, 4, pp. 788-799. | Technology | Diamond morphology - surfaces |
DS201510-1765 2014 | Dvoichenkova, G.P. | Mineral formations on natural diamond surface and their destruction using electrochemically modified mineralized water. | Journal of Mining Science, Vol. 50, 4, pp. 788-799. | Technology | Diamond morphology |
| Abstract: The article describes modeling and analysis of formation, attachment and dissolving of mineral substances on surface of diamond crystals. Based on the thermodynamic analysis and experimental research, the author validates deposition of chemical compounds as the main factor to govern mineral formations on natural diamond surface under contact with mineralized water in the occurrence conditions of kimberlite ore and during mining and processing. The efficiency of electrochemically modified water in dissolving and removal of mineral formations from diamond surface is ascertained. |
DS201504-0194 2015 | Dymshits, A., Sharygin, I., Litasov, K., Shatskiy, A., Gavryushkin, P., Ohtani, E., Suzuki, A., Funakoshi, K. | In situ observation of the pyroxene majorite transition in Na2MgSi5O12 using synchroton radiation and Raman spectroscopy of Na-majorite. | American Mineralogist, Vol. 100, pp. 378-384. | Mantle | Majorite |
DS201508-0352 2015 | Eaton-Magana, S. | Comparison of luminescence life times from natural and laboratory irradiated diamonds. | Diamond and Related Materials, Vol 58, pp. 94-102. | Technology | Diamond - luminescence |
DS201510-1766 2015 | Eaton-Magana, S., Ardon, T. | Effect of LPHT treatment on natural Type 1A diamonds. | GSA Annual Meeting, Paper 300-10, 1p. Abstract only Booth | Technology | LPHT |
DS201512-1915 2015 | Ebert, K., Brodaric, B. | GIS analyses of ice-sheet erosional impacts on the exposed shield of Baffin Island, eastern Canadian Arctic. | Canadian Journal of Earth Sciences, Vol. 52, 11, pp. 966-979. | Canada, Nunavut, Baffin Island | Geomorphology |
| Abstract: The erosional impacts of former ice sheets on the low-relief bedrock surfaces of Northern Hemisphere shields are not well understood. This paper assesses the variable impacts of glacial erosion on a portion of Baffin Island, eastern Canadian Arctic, between 68° and 72°N and 66° and 80°W. This tilted shield block was covered repeatedly by the Laurentide Ice Sheet during the late Cenozoic. The impact of ice-sheet erosion is examined with GIS analyses using two geomorphic parameters: lake density and terrain ruggedness. The resulting patterns generally conform to published data from other remote sensing studies, geological observations, cosmogenic exposure ages, and the distribution of the chemical index of alteration for tills. Lake density and terrain ruggedness are thereby demonstrated to be useful quantitative indicators of variable ice-sheet erosional impacts across Baffin Island. Ice-sheet erosion was most effective in the lower western parts of the lowlands, in a west-east-oriented band at around 350-400 m a.s.l., and in fjord-onset zones in the uplifted eastern region. Above the 350-400 m a.s.l. band and between the fjord-onset zones, ice-sheet erosion was not sufficient to create extensive ice-roughened or streamlined bedrock surfaces. The exception — where lake density and terrain ruggedness indicate that ice-sheet erosion had a scouring effect all across the study area — was in an area from Foxe Basin to Home Bay with elevations <400 m a.s.l. These morphological contrasts link to former ice-sheet basal thermal regimes during the Pleistocene. The zone of low glacial erosion surrounding the cold-based Barnes Ice Cap probably represents the ice cap’s greater extent during successive Pleistocene cold stages. Inter-fjord plateaus with few ice-sheet bedforms remained cold-based throughout multiple Pleistocene glaciations. In contrast, zones of high lake density and high terrain ruggedness are a result of the repeated development of fast-flowing, erosive ice in warm-based zones beneath the Laurentide Ice Sheet. These zones are linked to greater ice thickness over western lowland Baffin Island. However, adjacent lowland surfaces with similar elevations of non-eroded, weakly eroded, and ice-scoured shield bedrock indicate that—even in areas of high lake density and terrain ruggedness—the total depth of ice sheet erosion did not exceed 50 m. |
DM201508-0760 2015 | Ecclestone, C. | Tango Mining .. Strategy Oena .. Coverage by analyst | Hallgarten & Company cecclestone @hallgartenco.com, July 6, 16p. | Africa, South Africa | News item - Tango Mining |
DS201507-0310 2015 | Edwards, S.J., Schellart, W.P., Duarte, J.C. | Geodynamic models of continental subduction and obduction of overriding plate forearc oceanic lithosphere on top of continental crust. | Tectonics, Vol. 34, 7, pp. 1494-1515. | New Zealand | Subduction |
DM201508-0761 2015 | Ehud Arye Laniado | Tackling debts & fears in today's diamond market. | ehudlaniado.com, June 29, 8p. | Global | News item - markets |
DM201508-0762 2015 | Ehud Arye Laniado | Dark Clouds loom over the diamond industry. | ehudlaniado.com, July 13, 5p. | Global | News item - economics |
DM201508-0763 2015 | Ehud Arye Laniado | Antwerp and diamonds: a rocky love story. | EAL, July 15, 4p. | Europe | News item - diamond centers -history |
DM201508-0764 2015 | Ehud Arye Laniado | Miners vs the Midstream: who needs to change? | info @ehudlaniado.com, July 27, 5p. | Global | News item - value chain |
DM201509-0765 2015 | Ehud Arye Laniado | India where it all began. | ehudlaniado.com, July 29, 3p. | India | News item - history |
DM201509-0766 2015 | Ehud Arye Laniado | Not a price correction but a market correction. | ehudlaniado.com, Aug. 3, 3p. | Global | News item - markets |
DM201509-0767 2015 | Ehud Arye Laniado | New York diamond center. | ehudlaniado.com, Aug. 5, 4p. | United States | News item - history |
DM201509-0768 2015 | Ehud Arye Laniado | The booming bear: the story of Russian diamond industry. | ehudlaniado.com, Aug. 13, 5p. | Russia | News item - history |
DM201509-0769 2015 | Ehud Arye Laniado | Is the midstream working for a wage? A call for more profitable midstream for a stronger industry. | ehudlaniado.com, Aug. 17, 5p. | Global | News item - polishers |
DM201509-0770 2015 | Ehud Arye Laniado | Key changes offer bright future for diamond industry. | info @ehudlaniado.com, Aug. 24, 3p. | Global | News item - economics |
DM201509-0771 2015 | Ehud Arye Laniado | Diamond centers - Dubai profiled. | ehudlaniado.com, Aug. 26, 4p. | Dubai | News item - Dubai |
DM201510-2034 2015 | Ehud Arye Laniado | A call for change, a call for hope. | ehudlaniado.com, Aug. 31, 4p. | Global | News item - market |
DM201510-2035 2015 | Ehud Arye Laniado | Hong Kong's rise to diamond fame. | ehudlaniado.com, 4p. | Hong Kong | News item - Hong Kong |
DM201510-2036 2015 | Ehud Arye Laniado | The awakening of diamonds in Chin a ( jewellery) | ehudlaniado.com, Sept. 9, 4p. | China | News item - markets |
DM201510-2037 2015 | Ehud Arye Laniado | Stability in the diamond market. | ehudlaniado.com, Sept. 21, 5p. | Global | News item - markets |
DM201510-2038 2015 | Ehud Arye Laniado | Diamond mining in Namibia - past and present. | ehudlaniado.com, Sept. 24, 3p. | Africa, Namibia | News item - history |
DM201511-2139 2015 | ehud Arye Laniado | The diamonds's place in the consumer's heart. | ehudlaniado.com, Oct. 5, 3p. | Global | News item - history |
DM201511-2140 2015 | Ehud Arye Laniado | Understanding seasonality in diamond sales. | ehudlaniado.com, Oct. 15, 8p. | Global | News item - markets |
DM201512-2243 2015 | Ehud Arye Laniado | $ 48 .4 million for 'blue Moon' diamond eclipses world auction record. | ehudlaniado.com, Nov. 12, 2p. | Global | News item - diamond notable |
DM201512-2244 2015 | Ehud Arye Laniado | Retail Economics: why consolidation could be helping the entire diamond retail industry. | ehudlaniado.com, Nov. 25, 3p. | Global | News item - prices |
DS201505-0241 2015 | Elazar, O., Kessel, R., Navon, O. | Fluids and melts in equlibrium with carbonated hydrous eclogite system at 4-6 Gpa and 900-1200 C. | Israel Geological Society, Abstracts 1p. | Technology | Eclogite |
DS201506-0264 2015 | El-Desoky, H., Khalil, A.E., Salem, A.K.A. | Ultramafic rocks in Gabal El-Rubshi, Central Eastern Desert, Egypt: petrography, mineral chemistry, and geochemistry constraints. | Arabian Journal of Geosciences, Vol. 8, 5, pp.2607-2631. | Africa, Egypt | Ultramafic rocks - general |
DC201511-2380 2015 | Element Six | Element Six announced the use of its researchers at MQ Photonics to demonstrate a diamond laser 20 times more powerful than previous ones. | Element Six, Sept. 23, 1/2p. | Technology | News item - Element Six |
DC201509-1481 2015 | Elkedra Diamonds NL. | Canadian master diamond cutter Mike Botha to craft the Esperanza diamond in Arkansas. | Embee Diamonds, Aug. 27, 1/2p. | United States, Arkansas | News item - Embee |
DM201503-0772 2015 | EMJ Womp | Rio Tinto developing Diavik's A21 pipe. | womp-int.com, Jan. 29, 1/3p. | Canada, Northwest Territories | News item - Rio Tinto |
DC201508-1482 2015 | EMU NL | Sale of Superkolong diamond interest final payment from El Nino Mining. | EMU NL, July 17, 1/8p. | Australia | News item - press release |
DS201512-1916 2015 | Evans, K.A., Powell, R. | The effect of subduction on sulphur, carbon and redox budget of lithospheric mantle. | Journal of Metamorphic Geology, Vol. 33, 6, pp. 649-670. | Mantle | Subduction |
| Abstract: Subduction of hydrated lithospheric mantle introduces Hinline imageO, ferric iron, oxidized carbon and sulphur to the subduction zone system. The fate of these components is poorly known, but is intimately linked to the global geochemical cycles of iron, carbon and sulphur, the genesis of arc-related ore deposits, the temporal evolution of mantle redox state and subduction-related earthquakes and magmatism. thermocalc is used to provide first-order constraints on the effect of subduction zone metamorphism on metamorphic redistribution of iron, carbon, sulphur and water in ultramafic rocks via construction of P?T and T-X(O) pseudosections with open system calculation of the effect of fluid loss. The calculations replicate observed mineral assemblages in high-P to low-T ultramafic rocks at P?T conditions consistent with those suggested by other workers. The results are consistent with open system fluid loss without significant fluid infiltration. Water loss is complete by 850 inline imageC, the corresponding depth of fluid loss being consistent with that inferred for earthquakes in subducting slabs. Losses of carbon and sulphur are relatively minor, at around <5% and <1%, respectively, so it is envisaged that most carbon and sulphur subducted in ultramafic lithologies is transported to >5 GPa, below the depths of the source zone for arc volcanoes. Oxygen activity for rocks in closed systems that evolve with a fixed redox budget is calculated to change from ?FMQ ?1 at 350 inline imageC to over ?FMQ +3 at 850 inline imageC. This result emphasizes the need to consider redox budget as well as oxygen activity when the results of experiments performed at fixed oxygen activity relative to some buffer are interpreted in the context of natural systems. In open systems, devolatilization is calculated to increase the redox budget and oxygen activity of the residue via loss of methane and Hinline imageS at the brucite-out and serpentine-out reactions respectively. No fluid-induced mechanism for oxidation of sub-arc mantle by transfer of redox budget from hydrated ultramafic lithologies to the overlying sub-arc mantle was identified, although further thermodynamic data on fluid species such as Sinline image are required to confirm this. |
DM201510-2108 2015 | Evans, N. | Bit by bit sale for Ellendale. | The West Australian, Sept. 3, 1p. | Australia | News item - Kimberley Diamonds |
DM201512-2245 2015 | Evans, N. | Diamond Daze - Ellendale Upbeat corporate forecasts, it transpires, were based on no more than an assumption that Tiffany would pay more for yellow diamonds. | The Australian News , Nov. pp. 8-10. pdf | Australia | News item - Kimberley Diamonds |
DM201501-0475 2014 | Even-Zohar, C. | Another certificate movie: Dirty Dancing … using analogy to ethical grading and different labs. | Diamond Intelligence Briefs ( Courtesy of Chaim), DIB 839, Nov. 25, pp. 8941-8945. | Technology | News item - diamond certificates |
DM201501-0476 2014 | Even-Zohar, C. | Analyzing Indian dreams of duty free jewelry exports to the United States. | Diamond Intelligence Briefs ( Courtesy of Chaim), DIB 838, Nov. 19, pp. 8927-8930. | India, United States | News item - GSP program |
DM201501-0477 2014 | Even-Zohar, C. | Tyler Gillard: 'OECD has no plans to issue precious stones ( or diamonds) Due Diligence Guidelines at this time. Discusses The white paper initiative. | Diamond Intelligence Briefs ( Courtesy of Chaim), DIB 837, Nov. 12, pp. 8913-17. | Global | News item - OECD |
DM201502-0774 2015 | Even-Zohar, C. | Analyzing Indian dreams of duty-free jewelry exports to the United States. | Idex Magazine, No. 297, Jan. pp. 112-117. | India | News item - jewelry |
DM201503-0775 2015 | Even-Zohar, C. | Economics 101: a course on added value. | DIB , Vol. 30, 848, Jan. 28, pp. 9038-9042. | Global | News item - statistics |
DM201503-0776 2015 | Even-Zohar, C. | Diamond miracles from the Holy Land…. Offical diamond import and export statistics ( KP and Israel)…. Observations and concerns. | DIB , Vol. 30, 845, Jan. 7, pp. 9008-9010. | Global | News item - statistics |
DM201503-0777 2015 | Even-Zohar, C. | False ABN-AMRO withdrawal scare in India. | DIB , Vol. 30, 846, Jan. 15, pp. 9018-9020. | India | News item - banking, financing |
DM201503-0778 2015 | Even-Zohar, C. | Taking one's banker to court. ABN-AMRO | DIB , Vol. 30, 847, Jan. 22, pp. 9029-9032. | India | News item - legal |
DM201506-0779 2015 | Even-Zohar, C. | The year the industry lost confidence in its future. | Diamond Intelligence Briefing Courtesy of Chaim), Vol. 30, 855, Apr. 27, 3p. | Global | News item - supply chain |
DM201507-0780 2015 | Even-Zohar, C. | ABN AMRO's Indian exit: Induslnd bank catapults into $ 1 billion exposure. | Diamond Intelligence Briefing ( Courtesy of Chaim), Vol. 30, 854, Apr. 13, 8p. | India | News item - Induslnd |
DM201507-0781 2015 | Even-Zohar, C. | Botswana beneficiation from a marketing agreement perspective: local rough supplies - a promise broken. | Diamond Intelligence Briefing ( Courtesy of Chaim), Vol. 30, 856, May 11, 8p. | Africa, Botswana | News item - beneficiation |
DM201509-0773 2015 | Even-Zohar, C. | Love and hate on the rough supply side. | Diamond Intelligence Briefing, Vol. 30, no. 860, July 23, 8p. | Global | News item - rough |
DM201510-2039 2015 | Even-Zohar, C. | The emerging secrets of a bank destined to close. Antwerp Diamond Bank ( ADB) | Diamond Intelligence Briefing ( Courtesy of Chaim), Vol. 30, no. 862, Sept. 11, 11p. | Europe, Belgium | News item - ADB legal |
DM201511-2209 2015 | Even-Zohar, C. | Beneficiation from a marketing agreement perspective… factories, management and history. | Idex Magazine, No. 306, pp. 38-62. | Africa, Botswana | Beneficiation, production |
| Abstract: The President of Botswana, the Honorable Seretse Khama Ian Khama, has all the legitimate means to fix the plight of his country's ailing diamond-beneficiation sector, i.e., factory closings and the retrenchment of some 700 workers during the past few months. Only one thing is needed to turn the situation around: to muster the political will and courage to do so. This may sound like an impossible challenge given today's diamond market and economic realities - but it can be done. In fact, it must be done, according some stakeholders in Botswana. This isn't for someone from the outside to say. The president of Botswana heads an independent sovereign government, and it is up to him to set the policy priorities in his country. |
DM201512-2246 2015 | Even-Zohar, C. | Violating the 11th commandment: thou shalt not discount… Supplier and Client stood eyeball-to-eyeball in price standoff - De Beers blinked first. | Diamond Intellgence Briefing (Courtesy of Chaim), Vol. 30, no. 864, Oct. 26, 9p. | Global | News item - De Beers |
DM201512-2247 2015 | Even-Zohar, C. | The riddle of De Beers and $ 5 billion of "invisible" production… | Diamond Intellgence Briefing (Courtesy of Chaim), Vol. 30, no. 863, Oct. 1, 9p. | Global | News item - production figures |
DS201506-0266 2015 | Even-Zohar, C. | Taxing the Antwerp diamond industry into prosperity. | Idex Magazine, No. 301, pp. 111-117. | Europe | Economics |
DS201507-0311 2015 | Even-Zohar, C. | Temporary color enhancement: a potential game changer for industry and grading labs. | Diamond Intelligence Briefing ( Courtesy of Chaim), Vol. 30, no. 857, May 28, 8p. | Technology | Diamond - colours |
DS201508-0354 2015 | Even-Zohar, C. | Temporary colour enhancement …. Treatment, story so far, timing, legal and commercial problems of dishonesty. | Idex Magazine, No. 303, July pp. 36-62. | Technology | Diamond color enhancement |
DS201504-0195 2015 | Ewing, I. | Ice, ice baby A frigid winter paves the way for Gahcho Kue. | Canadian Institute of Mining and Metallurgy, March-April 2p. | Canada, Northwest Territories | Deposit - Gahcho Kue |
DS201510-1767 2015 | Eyike, A., Ebbing, J. | Lithospheric structure of the West and Central African Rift system from regional three dimensional gravity modelling. | South African Journal of Geology, Vol, 118, no. 3, pp. 285-298. | Africa, East Africa | Geophysics - gravity |
| Abstract: A three-dimensional interpretation of the central part of the West and Central African Rift System (WCARS) is presented using the Earth Gravity Model 2008 (EGM2008). The 3-D model presented here provides new insights into the regional lithospheric structure of the central sector of the WCARS. The 3-D model reveals a possible crustal thickness and density distribution beneath the rift system, and the depth extent of magmatic activity in the Benue Trough is revealed for the first time. Because of asthenospheric uplift, the crust under the Benue Trough is thinned. The zone of crustal thinning (<30 km) coincides with the trace of an intrusion beneath the trough, and the maximum of which is attained in the Yola Basin. The Adamawa and Kapsiki Plateaus, on the other hand, show by far the largest crustal thickness in the region (34 to 36 km). The inferred zone of intrusion coincides with the maximum gravity anomaly of the rift zone. The great depth (ca. 14 km) to the top of the intrusion along the rift may explain the absence of magmatism in the Benue Trough compared to the Cameroon Volcanic Line (CVL) or the East African Rift System (EARS). The relatively small nature of the intrusion leads to the conclusion that small-scale asthenospheric upwelling might be responsible for the thinning of the crust and subsequent rifting of the Benue Trough. |
DS201501-0007 2014 | Fahrenkamp-Uppenbrink, J. | What drives Earth's thermodynamic engine? | Science, Vol. 346, 6214, pp. 1184-1185. | Mantle | Athenosphere, magmatism |
DS201512-1917 2015 | Fajber, R., Simandl, G.J., Luck, P., Neetz, M. | Biogeochemical methods to explore for carbonatites and related mineral deposits: an orientation survey, Blue River area, British Columbia, Canada. | Symposium on critical and strategic materials, British Columbia Geological Survey Paper 2015-3, held Nov. 13-14, pp. 241-244. | Canada, British Columbia | Carbonatite |
| Abstract: Carbonatites host economic deposits of niobium (Nb), rare earth elements (REE), phosphate, baddeleyite (natural zirconia), vermiculite, and fl uorspar, and historically, supplied copper, uranium, carbonate (for cement industries) and sodalite (Pell, 1994 and Simandl, this volume). The Upper Fir carbonatite is in southeastern British Columbia, approximately 200 km north of Kamloops (Fig. 1). It is one ofmany known carbonatite occurrences in the British Columbia alkaline province, which follows the Rocky Mountain Trench and extends from the southeastern tip of British Columbia to its northern boundaries with the Yukon and Northwest Territories (Pell, 1994). The Upper Fir is a strongly deformed carbonatite with an indicated mineral resource of 48.4 million tonnes at 197 ppm of Ta2O5 and 1,610 ppm of Nb2O5, and an inferred resource of 5.4 million tonnes at 191 ppm of Ta2O5 and 1760 ppm of Nb2O5 (Kulla et al. 2013). The Nb, Ta, and vermiculite mineralization is described by Simandl et al. (2002, 2010), Chong, et al, (2012), and Chudy (2014). In this document we present the results of an orientation survey designed to determine the biogechemical signature of a typical carbonatite in the Canadian Cordillera. This survey suggests that needles and twigs of White Spruce (Picea glauca) and Subalpine Fir (Abies lasio carpa) are suitable sampling media to explore for carbonatites and carbonatite-related rare earth elements (REE), niobium (Nb), and tantalum (Ta) deposits. |
DS201511-1834 2015 | Fedortchouk, Y. | Diamond resorption features as a new method of examining conditions of kimberlite emplacement. | Contributions to Mineralogy and Petrology, Vol. 170, 19p. | Global | Diamond morphology - etch pits |
| Abstract: The study develops a new approach utilizing parameters of trigonal etch pits on diamond crystals to infer the conditions of diamond residence in kimberlite magma. Diamond crystals from dissolution experiments conducted at 1 GPa and 1150-1350 °C in the presence of H2O-rich or CO2-rich fluid were studied with atomic force microscopy (AFM). The AFM data of resorbed diamond surfaces show that much deeper surface relief was produced in CO2 fluid. It also clearly distinguishes the profiles of the trigonal etch pits forming regular flat-bottomed trigons in H2O fluid, and round- or pointed-bottomed trigons in CO2 fluid. The relationship between the diameter and the depth of the trigonal pits is found to be another important indicator of the fluid composition. Dissolution in H2O fluid develops trigons with constant diameter and variable depth where the diameter increases with temperature. Trigons developed in CO2 fluid have a large range of diameters showing a strong positive correlation with the depth. The developed criteria applied to the natural diamond crystals from three Ekati Mine kimberlites indicate significant variation in CO2-H2O ratio and temperature of their magmatic fluid. This conclusion based on diamond resorption agrees with the mineralogy of microphenocrysts and groundmass of the studied kimberlites offering new method to study crystallization conditions of kimberlite magma.
Keywords |
DS201512-1918 2015 | Feng, J., Tappert, M.C., Rivard, B.A., Fulop, A., Rogge, D., Tappert, R. | Acquiring crustal dilution dat a and kimberlite compositional information from drill core using SWIR hyper spectral imagery from the Tango extension kimberlite. | 43rd Annual Yellowknife Geoscience Forum Abstracts, abstract p. 39. | Canada, Northwest Territories | Deposit - Tango |
| Abstract: Short-wave infrared (SWIR, 1.90-2.36 µm) hyperspectral imagery collected from 171 meters of drill core from the diamondiferous Tango Extension kimberlite using a high spatial resolution imaging system (pixel size: 1.43 x 1.43 µm) was analyzed to create compositional maps that show the distribution of different crustal (dilution) components and different kimberlite types along the drill core. Three types of crustal dilution components were identified in the compositional maps: carbonate, a carbonate-mudstone mixture, and mudstone. Five spectrally distinct types of kimberlite were identified, which differ mainly in their level of hydration and the amount of crustal micro-dilution they contain. Accompanying the compositional maps are depth profiles that provide quantitative abundance information for each compositional component (dilution and kimberlite). These profiles show the abundance of macro-dilution relative to kimberlite and the spatial distribution of the different kimberlite types. Using depth profiles, compositional boundaries along the length of the drill core were identified and compared to the unit boundaries from the visual lithological log. The boundaries identified using the hyperspectral imagery correlate well with the boundaries recorded during visual logging. This study demonstrates that hyperspectral imagery is well suited to the task of mapping the distribution of spectrally distinct kimberlite types, and quantifying kimberlite micro- and macro-dilution by crustal rocks. |
DS201501-0008 2014 | Fernandes, A.F., Karfunkel, J., Hoover, D.B., Sgarbi, P.B.De Al., Sgarbo, G.N.C., Oliveira, G.D., Gomes, J.C.de S.P., Kambrock, K. | The basal conglomerate of the Capacete Formation ( Mat a da Corda Group) and its relation to diamond distributions in Coromandel, Minas Gerais State, Brazil. | Brazil Journal of Geology, Vol. 44, 1, pp. 91-103. | South America, Brazil | Coromandel district |
| Abstract: The diamond bearing district of Coromandel is located in the northwestern part of Minas Gerais, within the Alto Paranaíba Arch, famous for the discovery of most of Brazil's large diamonds above 100 ct. Detailed mapping, aimed at characterizing the Mata da Corda Group of Upper Cretaceous age of Coromandel, has been carried out. This Group was divided into the Patos Formation, composed of kimberlitic and kamafugitic rocks, and the Capacete Formation, presented by conglomerates, pyroclastic rocks, arenite and tuffs. Exposures of the latter Formation have been studied in detail at the small abandoned mine called Canastrel, as well as in the headwater of Santo Antônio do Bonito River. The results have been compared to studies of the kimberlite bodies in the nearby Douradinho River. Kimberlite indicator minerals from these localities show the same compositional trend. Moreover, in the basal conglomerate of the Garimpo Canastrel two diamonds diamonds have been recovered and described. The Garimpo Wilson, situated in the headwater of the river Santo Antônio do Bonito in paleo-alluvium, is composed of material exclusively derived from the erosion of the Capacete Formation and Precambrian (sterile) Canastra quartzites and schists. These detailed investigations suggest that the basal conglomerates of the Capacete Formation represent the main source rock of the alluvial diamond deposits in the Coromandel region. |
DS201505-0250 2015 | Ferracutti, G.R., Gargiulo, M.F., Ganuza, M.L., Bjerg, E.A., Castro, S.M. | Determination of the spinel group end-members based on electron microprobe analyses. | Mineralogy and Petrology, Vol. 109, 2, pp. 153-160. | Technology | Geochronology |
DS201511-1835 2012 | Ferreira, J. | Motete dyke project … preliminary diamond grade and tonnage model for the Motete dyke. | MSA Group for Paragon Diamonds, April, 17p. Available pdf | Africa, Lesotho | Microdiamonds - responses |
| Abstract: The Motete Dyke is a diamondiferous kimberlite situated in the mountains of Lesotho. Total liberation diamond recovery methods were used to analyse representative samples from localities along the 1 500 m outcrop length of the dyke for grade modeling purposes. The microdiamond grade and stone density is remarkably consistent throughout the exposed area of the dyke. A grade of some 60 cpht at +1.18 mm and 90 cpht at +0.85 mm is estimated for the dyke at surface. In order to extend the estimate to deeper levels it will be necessary to drill into the dyke to obtain more sampling material for total liberation analysis. Initial tonnage calculations indicate that the dyke contains an estimated 525 000 carats at +0.85 mm with an additional 50 000 carats in every additional 10 m depth below 2450 m elevation, assuming an average dyke width of 1.44 m and density of 2.57 tons/m3. Bulk sampling of the dyke is recommended to recover a parcel of diamonds for valuation and to confirm the diamond size frequency and content model. |
DS201506-0267 2015 | Ferrero, S., Wunder, B., Walczak, K., O'Brien, P.J., Ziemann, M.A. | Preserved near ultrahigh-pressure melt from continental crust subducted to mantle depths. | Geology, Vol. 43, 5, pp. 447-450. | Mantle | Bohemian |
DC201501-1483 2014 | Firestone Diamonds plc. | Liqhobong mine development project update. | Firestone Diamonds plc., Dec. 2, 3p. | Africa, Lesotho | News item - press release |
DC201504-1484 2015 | Firestone Diamonds plc. | Highlights from results six months to 31 December. Liqobong, BK-11, finances | Firestone Diamonds plc., Mar. 12, 14p. | Africa, Lesotho, Botswana | News item - press release |
DC201506-1485 2015 | Firestone Diamonds plc. | Proposed standby debt facility and restructuring of the existing mezzanine facility. Liqhobong | Firestone Diamonds plc., Apr. 24, 3p. | Africa, Lesotho | News item - press release |
DC201507-1486 2015 | Firestone Diamonds plc. | Liqhobong mine development project update. | Firestone Diamonds plc., June 23, 4p. | Africa, Lesotho | News item - press release |
DC201508-1487 2015 | Firestone Diamonds plc. | Sale of Botswana operations. BK11 mine to Tango. | Firestone Diamonds plc., July 9, 2p. | Africa, Botswana | News item - press release |
DC201511-2381 2015 | Firestone Diamonds plc. | Update on the sale of the Botswana operations to Tango Mining Limited … requested an extension to the timetable. | Firestone Diamonds plc., Oct. 2, 1p. | Africa, Botswana | News item - press release |
DC201511-2382 2015 | Firestone Diamonds plc. | Final results for year ended 30 June 2015. Liqhobong on budget.. Capital investment US $ 82.9 million … restructuring of Botswana assets. | Firestone Diamonds plc., Oct. 6, 3p. | Africa, Lesotho | News item - press release |
DC201511-2383 2015 | Firestone Diamonds plc. | Update on the sale of the Botswana operations and extension to Tango to April 8, 2016. | Firestone Diamonds plc., Oct. 13, 1p. | Africa, Botswana | News item - press release |
DS201504-0196 2012 | 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. | Technology | Diamond recovery |
DS201504-0197 2012 | Firsching, M., Muhlbauer, J., Nachtrab, F., Uhlmann, N. | Detection of enclosed diamonds using dual energy X-ray imaging. | 18th. World Conference on Nondestructive Testing held Durban SA, 7p. | Technology | Diamond recovery |
DS201502-0056 2015 | Firsov, A., Ashchepkov, I., Rikhvanov, L. | The alkali basaltic and picritic magmatism in Minusa and Kusnetsk basin - geochemical study. | Economic Geology Research Institute 2015, Vol. 17,, # 2797, 1p. Abstract | Russia | Picrite |
DC201512-2432 2015 | Five Star Diamonds Limited | Listing in H1 2016 The company plans to develop a 3.5 hectare kimberlite pipe at its Catalano project, Goias district. | ProactiveInvestors @sut8.co.uk, Nov. 27, 1p. | South America, Brazil | News item - Five Star Diamonds |
DM201510-2040 2015 | Forbes | Culli nan Heritage diamond 507.55 Carat type 11a has been cut by Chow Tai Fook … | Forbes Magazine, Sept. 4p. | Africa, South Africa | News item - diamond notable |
DS201501-0009 2014 | Fournier, D., Heagy, L., Corcoran, N., Cowan, D., Devriese, S.G.R., Bild-Enkin, D., Davis, K., Kang, S., Marchant, D., McMillan, M.S., Mitchell, M., Rosenkjar, G., Yang, D., Oldenburg, D.W. | Multi-EM systems inversion - towards a common conductivity model for Tli Kwi Cho complex. | SEG Annual Meeting Denver, 5p. Extended abstract | Canada, Northwest Territories | Deposit - Tli Kwi Cho, geophysics |
| Abstract: The magnetic and electromagnetic responses from airborne systems at Tli Kwi Cho, a kimberlite complex in the Northwest Territories, Canada, have received considerable attention over the last two decades but a complete understanding of the causative physical properties is not yet at hand. Our analysis is distributed among three posters. In the first we find a 3D magnetic susceptibility model for the area; in the second we find a 3D conductivity model; and in the third we find a 3D chargeability model that can explain the negative transient responses measured over the kimberlite pipes. In this second paper we focus upon the task of finding a conductivity model that is compatible with three airborne data sets flown between 1992 and 2004: one frequency-domain data set (DIGHEM) and two time-domain systems (AeroTEM and VTEM). The goal is to obtain a 3D model from which geologic questions can be answered, but even more importantly, to provide a background conductivity needed to complete the 3D IP inversion of airborne EM data. We begin by modifying our pre-existing 1D frequency and time domain inversion codes to produce models that have more lateral continuity. The results are useful in their own right but we have also found that 1D analysis is often very effective in bringing to light erroneous data, assisting in estimating noise floors, and providing some starting information for developing a background model for the 3D EM inversion. Here we show some results from our Laterally Constrained Inversion (LCI) framework. The recovered conductivity models seem to agree on the general location of the kimberlite pipes but disagree on the geometry and conductivity values at depth. The complete 3D inversions in time and frequency, needed to resolved these issues, are currently in progress. |
DS201509-0396 2015 | France, L., Chazot, G., Kornprobst, J., Dallai, L., Vannucci, R., Gregoire, M., Bertrand, H., Boivin, P. | Mantle refertilization and magmatism in old orogenic regions: the role of late-orogenic pyroxenites. | Lithos, Vol. 232, pp. 49-75. | Africa, Morocco, Cameroon, Jordan, Europe, France | Xenoliths |
| Abstract: Pyroxenites and garnet pyroxenites are mantle heterogeneities characterized by a lower solidus temperature than the enclosing peridotites; it follows that they are preferentially involved during magma genesis. Constraining their origin, composition, and the interactions they underwent during their subsequent evolution is therefore essential to discuss the sources of magmatism in a given area. Pyroxenites could represent either recycling of crustal rocks in mantle domains or mantle originated rocks (formed either by olivine consuming melt-rock reactions or by crystal fractionation). Petrological and geochemical (major and trace elements, Sr-Nd and O isotopes) features of xenoliths from various occurrences (French Massif-Central, Jordan, Morocco and Cameroon) show that these samples represent cumulates crystallized during melt percolation at mantle conditions. They formed in mantle domains at pressures of 1-2 GPa during post-collisional magmatism (possibly Hercynian for the French Massif-Central, and Panafrican for Morocco, Jordan and Cameroon). The thermal re-equilibration of lithospheric domains, typical of the late orogenic exhumation stages, is also recorded by the samples. Most of the samples display a metasomatic overprint that may be either inherited or likely linked to the recent volcanic activity that occurred in the investigated regions. The crystallization of pyroxenites during late orogenic events has implications for the subsequent evolution of the mantle domains. The presence of large amounts of mantle pyroxenites in old orogenic regions indeed imparts peculiar physical and chemical characteristics to these domains. Among others, the global solidus temperature of the whole lithospheric domain will be lowered; in turn, this implies that old orogenic regions are refertilized zones where magmatic activity would be enhanced. |
DS201505-0253 2015 | Fraser Institute | Fraser Institute annual survey for 2014. Mining jurisdictions listed. | Fraser Institute, 97p. Pdf | Global | Legal |
DS201504-0198 2015 | Frezzotti, M.L., Ferrando, S. | The chemical behaviour of fluids released during deep subduction based on fluid inclusions. | American Mineralogist, Vol. 100, pp. 352-377. | Mantle | Subduction |
DS201512-1919 2015 | Friis, H. | Primary and secondary mineralogy of the Ilimaussaq alkaline complex, south Greenland. | Symposium on critical and strategic materials, British Columbia Geological Survey Paper 2015-3, held Nov. 13-14, pp. 83-90. | Europe, Greenland | Alkalic |
| Abstract: The Ilímaussaq alkaline complex is among the largest known alkaline complexes in the world and has been studied since the early 19th century, when Giesecke explored Greenland for minerals. More than 230 different mineral species occur in the complex. Ilímaussaq is the type locality for 34 minerals, including 15 that have not been reported elsewhere. Some of these are rock-forming minerals and thus, although unique to Ilímaussaq, may not be considered rare. Among the minerals fi rst described from Ilímaussaq are two important sources for critical materials: steenstrupine- (Ce) and eudialyte (Table 1). Steenstrupine-(Ce) is the main target mineral for the Kvanefjeld multi-element project in the northern part of Ilímaussaq, whereas eudialyte is targeted at the Tanbreez project in the southern part known as Kringlerne (Fig. 1). The fi rst detailed mapping and petrological studies of the complex were published by Ussing (1912), who also defi ned the term ‘agpaitic’ for rocks where the molar ratio (Na+K)/ Al is greater than or equal to 1.2. Since then, the distinction between agpaitic and miaskitic has changed from being based on just rock chemistry to being based more on mineral paragenesis. Sørensen (1997) defi ned agpaitic as peralkaline rocks in which High Field Strength Elements (HFSE; e.g., Zr and Ti) are hosted in complex minerals such as eudialyte and rinkite. Rocks with high alkalinity, where HFSE are hosted in minerals such as zircon, are considered miaskitic. Khomyakov (1995) further developed the agpaitic classifi cation by introducing the term hyperagpaitic for the most evolved syenites. Hyperagpaitic rocks are characterised by containing water soluble minerals (e.g., natrosilite and natrophosphate) and complex phosphosilicates (e.g., steenstrupine-(Ce) and vuonnemite; Khomyakov, 1995). The Ilímaussaq complex is one of several alkaline complexes formed during Mesoproterozoic rifting in the southwestern part of Greenland, which collectively is called the Gardar province (Upton, 2013). With an age of ~1.6 Ga, Ilímaussaq is the youngest major intrusion of the Gardar province (Waight et al., 2002; Krumrei et al., 2006). |
DS201506-0268 2015 | Frizon de Lamotte, D., Fourdan, B., Leleu, S., Leparmentier, F., de Clarens, P. | Style of rifting and the stages of Pangea break up. | Tectonics, Vol. 34, 5, pp. 1009-1029. | Global, Russia | Pangea |
DS201501-0010 2003 | Fulgro | HeliFALCONtm gravity gradiometer Gahcho Kue kimberlite pipes. ( Kennady Lake JV) | fugro.com, 2p. | Canada, Northwest Territories | Deposit - Gahcho Kue geophysics |
DS201505-0233 2015 | Furlani, S., Ninfo, A. | Is the present the key to the future? | Earth Science Reviews, Vol. 142, pp. 38-46. | Global | Geomorphology |
DS201501-0011 2015 | Fusciardi, L. | De Beers Canada - technology and innovation across the diamond value chain. | PDAC 2015, 1/4p. Abstract | Canada | De Beers |
DS201503-0144 2015 | Gaillou, E., Post, J.E., Byne, K.S., Butler, J.E. | Study of the Blue Moon diamond. ( from Cullinan) | Gems & Gemology, Vol. 50, 4, winter 2014, 9p. | Africa, South Africa | Diamonds notable |
| Abstract: The Blue Moon diamond, discovered in January 2014 at the historic Cullinan mine in South Africa, is of significance from both trade and scientific perspectives. The 29.62 ct rough yielded a 12.03 ct Fancy Vivid blue, Internally Flawless gem. The authors were provided the opportunity to study this rare diamond at the Smithsonian Institution before it went on exhibit at the Natural History Museum of Los Angeles County. Infrared spectroscopy revealed that the amount of uncompensated boron in the diamond was 0.26 ± 0.04 ppm, consistent with measurements of several large type IIb blue diamonds previously studied. After exposure to short-wave ultraviolet light, the Blue Moon displayed orange-red phosphorescence that remained visible for up to 20 seconds. This observation was surprising, as orange-red phosphorescence is typically associated with diamonds of Indian origin, such as the Hope and the Wittelsbach-Graff. Time-resolved phosphorescence spectra exhibited peaks at 660 and 500 nm, typical for natural type II blue diamonds. As with most natural diamonds, the Blue Moon showed strain-induced birefringence. |
DS201504-0199 2015 | Gannoun, A., Burton, K.W., Barfod, D.N., Schiano, P., Vlastelic, I., Halliday, A.N. | Resolving mantle and magmatic processes in basalts from the Cameroon volcanic line using the Re-Os isotopic system. | Lithos, Vol. 224-5, pp. 1-12. | Africa, Cameroon | Alkaline rocks, basalts |
DS201508-0355 2015 | Garanin, V.K. | The Fersman mineralogical museum in the 21st century: past, present and future, | Mineral @fmmm.ru, Vol. 18, 3, pp. 24-41. | Russia | History - Fersman |
DS201506-0269 2014 | Garanin, V.K., Leybov, M.B. | Diamonds: a sketch portrait (History of discovery of Russian deposits and their genesis). | Mineralogical Almanac, Vol. 19, 1, pp. 30-47. | Russia | History |
DC201504-1488 2015 | Gem Diamonds Limited | Full year results for the period ending 31 December 2014. | Gem Diamonds Limited, Mar. 17, 3p. | Africa | News item - Gem Diamonds |
DC201504-1489 2015 | Gem Diamonds Limited | Full year 2014 results… Letseng, Ghaghoo. | Gem Diamonds Limited, Mar. 17, 3p. | Africa, Lesotho, Botswana | News item - press release |
DC201506-1490 2015 | Gem Diamonds Limited | Sales and operational update … Letseng, Ghaghoo. | Gem Diamonds Limited, May 21, 6p. | Africa, Lesotho, Botswana | News item - press release |
DC201509-1491 2015 | Gem Diamonds Limited | Trading update and projects Letseng and Ghaghoo performances. | Gem Diamonds Limited, July 30, 3p. | Africa, Lesotho, Botswana | News item - press release |
DC201510-2347 2015 | Gem Diamonds Limited | Sale of 357 ct. Letseng diamond $ 19.3 m | Gem Diamonds Limited, Sept. 14, 1p. | Africa, Lesotho | News item - press release |
DS201507-0312 2015 | Gernon, T.M., Spence, S., Trueman, C.N., Taylor, R.N., Rohling, E., Hatter, S.J., Harding, I.C. | Emplacement of Cabezo Maria lamproite volcano (Miocene) SE Spain. | Bulletin of Volcanology, Vol. 77, 6, pp. 52- | Europe, Spain | Lamproite |
DS201510-1768 2015 | Gerya, I.T. | Tectonic overpressure and underpressure in lithospheric tectonics and metamorphism. | Journal of Metamorphic Geology, Vol. 33, 8, pp. 785-800. | Mantle | Tectonics |
| Abstract: The lithostatic pressure concept is most commonly applied on a geological scale for lithospheric processes and related evolution of metamorphic rock complexes. Here, various aspects of non-lithostatic overpressure and underpressure phenomena in lithospheric tectonics and metamorphism are reviewed on the basis of recently published literature. The main conclusion from this short review is that these phenomena certainly exist in nature on all time and space scales including geological ones. They are, in particular, responsible for some geological processes, which are otherwise difficult to explain, such as downward water suction into the interior of subducting slabs. Magnitudes of overpressure and underpressure are strongly variable and may potentially reach up to ±100% of the lithostatic pressure and up to a GPa-level. These magnitudes depend mainly on the rheology of deforming rocks and on the nature of related tectonic process. Rheological heterogeneity of deforming rock units, which is common in nature, has a tendency to enhance overpressure and underpressures. Large overpressure can typically be expected in rheologically strong (dry) bending rock units, in particular in the mantle lithosphere. However, rheological weakness of rocks and small local deviatoric stresses do not guarantee the absence of large overpressures in these rocks. Therefore, the influence of significant tectonic overpressure and/or underpressure cannot be excluded for any metamorphic complex a priori but should be instead tested by exploring realistic thermomechanical models for envisaged tectono-metamorphic scenarios. Many lithospheric rocks subjected to large overpressures and underpressures cannot be studied as they do not exhume to the surface. Some controversy exists concerning overpressure magnitudes for the ultrahigh-pressure (UHP) rocks and several conflicting hypotheses are proposed, which need to be thoroughly tested in the future. In this respect, the Alpine region may offer a unique opportunity for the testing of geological-scale overpressures in (U)HP rocks by combining structural-geological and petrological data with realistic lithospheric-scale numerical modelling. |
DS201502-0057 2014 | Gifford, J.N., Mueller, P.A., Foster, D.A, Mogk, D.W. | Precambrian crustal evolution in the Great Falls Tectonic Zone: insights from xenoliths from the Montana Alkali province. | Journal of Geology, Vol. 122, Sept. pp. 531-548. | United States, Montana | Alkalic |
DS201507-0313 2015 | Gilio, M., Clos, F., Van Roermund, H.L.M. | The Frimingen garnet peridotite ( central Swedish Caledonides). A good example of the characteristic PTt path of a cold mantle wedge garnet peridotite. | Lithos, Vol. 230, pp. 1-16. | Europe, Sweden | Peridotite |
DS201505-0235 2015 | Giuliani, G.,Pivin, M., Fallick, A.E., Ohnenstetter, D., Song, Y., Demaiffe, D. | Geochemical and oxygen isotope signatures of mantle corundum megacrysts from the Mbuji-Mayi kimberlite, Democratic Republic of Congo and the Changle alkali basalt, China. | Comptes Rendus Geoscience, Vol. 347, 1, pp. 24-34. | Africa, Democratic Republic of Congo, China | Deposit - Mbuji-Mayi |
DS201512-1920 2015 | Gokhale, M., Madhura, Somani, R., Rakesh | Fullerenes: chemistry and its applications. | Mini-Reviews in Organic Chemistry, Vol. 12, 4, pp. 355-366. | Technology | Fullerenes |
| Abstract: Fullerenes being allotropes of carbon, have been considered as new class of molecules. Unlike diamond and graphite, this is made up of hollow carbon cage structure. The idea of spheroidal cage structures of C60 arose from construction of geodesic domes made by renowned architect Buckminster Fuller. Although fullerenes have low solubility in physiological media they finds promising biological applications. The photo, electrochemical and physical properties of C60 and other fullerene derivatives finds applications in medical fields. The ability of fullerenes to fit inside the hydrophobic cavity of HIV proteases makes them potential inhibitor for substrates to catalytic active site of enzyme. It possesses radical scavenging and antioxidant property. At the same time, when it exposed to light it can form singlet oxygen in high quantum yields which with direct electron transfer from excited state of fullerenes and DNA bases finally results in cleavage of DNA. The fullerenes are also used as a carrier for gene and drug delivery system. The associated low toxicity of fullerenes is sufficient to attract the researchers for investigation of these interesting molecules. |
DC201502-1492 2015 | Golden Saint Resources Ltd. | Golden Saint samples diamond recoveries at Baja. | Golden Saint Resources Ltd., Jan. 20, 1p. | Africa, Sierra Leone | News item - press release |
DC201504-1493 2015 | Golden Saint Resources Ltd. | Golden Saint Resources has recovered a total of 233 carats of diamonds during the first stage of its bulk sampling programme at Baja. | Golden Saint Resources Ltd., Mar. 10, 2p. | Africa, Sierra Leone | News item - press release |
DC201505-1494 2015 | Golden Saint Resources Ltd. | Quarterly update .. Moa project, Baja project and Tongo project brief summaries. | Golden Saint Resoures Ltd., Mar. 27, 1p. | Africa, Sierra Leone | News item - press release |
DC201505-1495 2015 | Golden Saint Resources Ltd. | GSR boss says new licences mean full steam ahead in Sierra Leone. | Golden Saint Resoures Ltd., Apr. 14, 1p. | Africa, Sierra Leone | News item - press release |
DC201506-1496 2015 | Golden Saint Resources Ltd. | Operational update: bulk sampling at Tongo, 9.475 carat diamond. | Golden Saint Resources Ltd., Apr. 27, 1p. | Africa, Sierra Leone | News item - press release |
DC201506-1497 2015 | Golden Saint Resources Ltd. | Highlights … Baja,Moa. | Golden Saint Resources Ltd., May 20, 40p. | Africa, Sierra Leone | News item - press release |
DC201506-1498 2015 | Golden Saint Resources Ltd. | Operation update - two stones 9.65 and 0.775 from Tongo | Golden Saint Resources Ltd., May 28, 1p. | Africa, Sierra Leone | News item - press release |
DC201507-1499 2015 | Golden Saint Resources Ltd. | Operational update ongoing sampling exercise in Tongo. | Golden Saint Resources Ltd., May 28,1p. | Africa, Sierra Leone | News item - press release |
DC201508-1500 2015 | Golden Saint Resources Ltd. | Appointment of technical and exploration consultant…. Rock Forage Consulting Services. John Ward | Golden Saint Resources Ltd., June 30, 1p. | Africa, Sierra Leone | News item - press release |
DC201508-1501 2015 | Golden Saint Resources Ltd. | Operational update to the market: diamonds found 2.25, 2.62, 4.41, 3.12, 89 carat under .05 carat | Golden Saint Resources Ltd., July 3, 1p. | Africa, Sierra Leone | News item - press release |
DC201510-2348 2015 | Golden Saint Resources Ltd. | Interim results .. Bulk sampling Tongo and Baja; Zimmi area artisanal. | Golden Saint Resources Ltd., Sept. 21, 2p. | Africa, Sierra Leone | News item - press release |
DC201511-2384 2015 | Golden Saint Resources Ltd. | Geological report on alluval and kimberlite of Baja, Tongo and Moa from Rock Forage consultants. | Golden Saint Resources Ltd., Oct. 1, 2p. | Africa, Sierra Leone | News item - press release |
DC201512-2433 2015 | Golden Saint Resources Ltd. | Placing, operational updates and board changes. Tongo bulk sampling | Golden Saint Resources Ltd., Nov. 24, 1p. | Africa, Sierra Leone | News item - press release |
DM201512-2248 2015 | Goldie, R. | Alrosa responds to weak Q3 markets. | SalmanResearch @salmanpartners.com, Nov. 25, 1/4p. | Russia | News item - Alrosa |
DS201504-0200 2015 | Goldie, R. | Diamonds .. Nominal US dollar price for rough diamonds graph | The 2015 Commodity Price Book, p. 31 ( I pg graph) | Global | Price index |
DS201506-0270 2015 | Gomes de Moraes Rocha, L., Bittencourt Pires, A.C., Chatck Carmelo, A., Oksum, E. | Curie surface of the alkaline provinces of Goias (GAP) and Alto Paranaiba ( APAP), central Brazil. | Journal of Volcanology and Geothermal Research, Vol. 297, pp. 28-38. | South America, Brazil | Kimberlites, Lineaments |
DS201512-1921 2015 | Gorbachev, N.S., Kostyuk, A.V., Shapovalov, Yu.B. | Experimental study of the basalt-carbonate-H2O system at 4 Gpa and 1100-1300C: origin of carbonatitic and high-K silicate magmas. | Doklady Earth Sciences, Vol. 464, 2, pp. 1018-1022. | Technology | Carbonatite |
DS201501-0012 2014 | Grad, M., Tiira, T., Olsson, S., Komminaho, K. | Seismic lithosphere asthenosphere boundary beneath the Baltic Shield. | GFF, Vol. 136, 4, pp. 581-598. | Europe, Finland, Sweden, Norway | Geophysics - seismic |
| Abstract: The problem of the existence of the asthenosphere for old Precambrian cratons is still discussed. In order to study the seismic lithosphere-asthenosphere boundary (LAB) beneath the Baltic Shield, we used records of nine local earthquakes with magnitudes ranging from 2.7 to 5.9. To model the LAB, original data were corrected for topography and Moho depth using a reference model with a 46-km-thick crust. For two northern events at Spitsbergen and Novaya Zemlya, we observe a low-velocity layer, 60-70-km-thick asthenosphere, and the LAB beneath Barents Sea was found at depth of c. 200 km. Sections for other events show continuous first arrivals of P-waves with no evidence for "shadow zone" in the whole range of registration, which could either be interpreted as the absence of the asthenosphere beneath the central part of the Baltic Shield, or that the LAB in this area occurs deeper (>200 km). The relatively thin low-velocity layer found beneath southern Sweden, 15 km below the Moho, could be interpreted as small-scale lithospheric heterogeneities, rather than asthenosphere. Differentiation of the lower lithosphere velocities beneath the Baltic Shield could be interpreted as regional heterogeneity or as anisotropy of the Baltic Shield lithosphere, with high velocities approximately in the east-west direction, and slow velocities approximately in the south-north direction. |
DS201502-0058 2015 | Graedel, T.E., Nassar, N.T. | The criticality of metals: a perspective for geologists. | In: Ore deposits of an evolving Earth, Geological Society of London,, Special Publication no. 393, pp. 291-302. | Global | Economics |
DS201503-0145 2015 | Green, D.H. | Experimental petrology of peridotites, including effects of water and carbon on melting in the Earth's upper mantle. | Physics and Chemistry of Minerals, Vol. 42, 2, pp. 95-122. | Mantle | Peridotite |
| Abstract: For over 50 years, the use of high-pressure piston/cylinder apparatus combined with an increasing diversity of microbeam analytical techniques has enabled the study of mantle peridotite compositions and of magmas derived by melting in the upper mantle. The experimental studies have been guided by the petrology and geochemistry of peridotites from diverse settings and by the remarkable range of mantle-derived magma types. Recent experimental study using FTIR spectroscopy to monitor water content of minerals has shown that fertile lherzolite (MORB-source upper mantle) at ~1,000 °C can store ~200 ppm H2O in defect sites in nominally anhydrous minerals (olivine, pyroxenes, garnet and spinel). Water in excess of 200 ppm stabilizes amphibole (pargasite) at P < 3 GPa up to the lherzolite solidus. However, at P > 3 GPa, water in excess of 200 ppm appears as an aqueous vapour phase and this depresses the temperature of the upper mantle solidus. Provided the uppermost mantle (lithosphere) has H2O < 4,000 ppm, the mantle solidus has a distinctive P, T shape. The temperature of the vapour-undersaturated or dehydration solidus is approximately constant at 1,100 °C at pressures up to ~3 GPa and then decreases sharply to ~1,010 °C. The strongly negative dT/dP of the vapour-undersaturated solidus of fertile lherzolite from 2.8 to 3 GPa provides the basis for understanding the lithosphere/asthenosphere boundary. Through upward migration of near-solidus hydrous silicate melt, the asthenosphere becomes geochemically zoned with the ‘enriched’ intraplate basalt source (>500 ppm H2O) overlying the ‘depleted’ MORB source (~200 ppm H2O). From the study of primitive MOR picrites, the modern mantle potential temperature for MORB petrogenesis is ~1,430 °C. The intersection of the 1,430 °C adiabat with the vapour-saturated lherzolite solidus at ~230 km suggests that upwelling beneath mid-ocean ridges begins around this depth. In intraplate volcanism, diapiric upwelling begins from shallower depths and lower temperatures within the asthenosphere and the upwelling lherzolite is enriched in water, carbonate and incompatible elements. Magmas including olivine melilitites, olivine nephelinites, basanites, alkali picrites and tholeiitic picrites are consequences of increasing melt fraction and decreasing pressure at melt segregation. Major element, trace element and isotopic characteristics of island chain or ‘hot-spot’ magmas show that they sample geochemically distinct components in the upper mantle, differing from MORB sources. There is no evidence for higher-temperature ‘hot-spot’ magmas, relative to primitive MORB, but there is evidence for higher water, CO2 and incompatible element contents. The distinctive geochemical signatures of ‘hot-spot’ magmas and their ‘fixed’ position and long-lived activity relative to plate movement are attributed to melt components derived from melting at interfaces between old, oxidised subducted slabs (suspended beneath or within the deeper asthenosphere) and ambient, reduced mantle. In convergent margin volcanism, the inverted temperature gradients inferred for the mantle wedge above the subducting lithosphere introduce further complexity which can be explored by overlaying the phase relations of appropriate mantle and crustal lithologies. Water and carbonate derived from the subducted slab play significant roles, magmas are relatively oxidised, and distinctive primary magmas such as boninites, adakites and island arc ankaramites provide evidence for fluxing of melting in refractory harzburgite to lherzolite by slab-derived hydrous adakitic melt and by wedge-derived carbonatite. |
DS201505-0246 2015 | 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.poster | Europe, Israel | Mineralogy |
DC201504-1502 2015 | Grizzly Discoveries Inc. | Brief note on overview .. Buffalo Head Hills and Birch Mountains. | Grizzley Discoveries Inc., Mar. 18, 1p. | Canada, Saskatchewan, Alberta | News item - press release |
DC201506-1503 2015 | Grizzly Discoveries Inc. | Renewed interest in diamonds.. Buffalo Hills project. | Grizzly Discoveries Inc., May 6, 1p. | Canada, Alberta | News item - press release |
DS201502-0060 2015 | Grocholski, B. | A lower mantle water cycle component. | Science, Vol. 347, 6220, Jan. 23, pp. 385-386. | Mantle | Water |
DS201509-0397 2015 | Grocholski, B. | Unlocking Earth's ancient magnetic past. | Science, Vol. 349, 6247, pp. 490-492. | Mantle | Paleomagnetism |
| Abstract: The magnetic field protects Earth's surface from deadly cosmic radiation and provides clues about the planet's interior. Tarduno et al. found that some of the oldest minerals on Earth, Jack Hills zircons, preserved a record of a magnetic field over 4 billion years ago (see the Perspective by Aubert). Earth's magnetic field appears to have been fully operational a mere few hundred million years after the planet formed. This suggests an early start for plate tectonics and an ancient cosmic radiation shield that was important for habitability. |
DS201510-1769 2015 | Grocholski, B. | Broadening the source for hotspots. | Science, Vol. 349, 6255, Sept. 25, pp. 1501-1502. | Mantle | Hotspots |
DS201511-1836 2015 | Grocholski, B. | Coupled constraints on core formation. | Science, Vol. 350, 6258, Oct. 16, pp. 289-290. | Mantle | Chemistry |
DM201505-0782 2015 | Grynberg, R. | Diamond cutting industry in Botswana. | Allafrica.com, Apr. 22, 2p. | Africa, Botswana | News item - opinion comments |
DS201511-1837 2015 | Gu, Y.J., Shen, L. | Noise correlation tomography of southwest western Canada sedimentary basin. | Geophysical Journal International, Vol. 202, pp. 142-162. | Canada, Alberta | Geophysics - seismics |
| Abstract: We analyse continuous recordings from 23 broadband seismic stations near Alberta, the southwestern sector of the Western Canada Sedimentary Basin. Noise correlation tomo-graphy based on vertical-component seismograms reveals below-average shear velocities at shallow and middle crustal depths in central Alberta, spanning across Proterozoic accreted terranes and Archean microcontinents. This observation likely results from extensive plate convergence and crustal melting during the Proterozoic eon. The overall correlation between the crustal velocities and presumed basement domains is lower than expected, however. In the lower crust, the main pattern of shear velocities is relatively concordant with the reported domain boundaries and key Precambrian structures appear to be intact. The shear velocities beneath the Loverna Block, the largest constituent of the Hearne craton, are 10?per?cent higher than the regional average. This prominent northeast striking seismic anomaly is moderately correlated with the regional heat flow and potentially represents the remnant core of the Archean Hearne province. The associated high velocities extend into the western part of the Medicine Hat Block, a possible Archean microcontinent with a debatable origin, and contribute to a strong east-west structural gradient in the lower crust. The presence and the continuity of this anomalous structure imply extensive communications among the various basement domains in southern Alberta during the assembly of the North American continent. |
DS201510-1770 2015 | Gudmundsson, A. | Collapse-driven large eruptions. | Journal of Volcanology and Geothermal Research, Vol 304, pp. 1-10. | Mantle | Magmatism |
| Abstract: For a typical poroelastic shallow crustal magma chamber, about 0.1% of the mafic magma and about 4% of the felsic magma are erupted and/or injected during magma-chamber rupture. Magma chambers with volumes of the order of several tens to several hundred cubic kilometres, as are common, are thus sufficiently large to supply magma to small or moderate eruptions. For large eruptions, however, a much higher percentage of the magma volume must be squeezed out of the chamber. For an ordinary poroelastic chamber, the excess pressure in the chamber falls exponentially during the eruption. For a large eruption to be possible, however, the excess pressure must be essentially maintained until the very end of the eruption. Here I show that caldera collapse can maintain the excess pressure through forced magma-chamber volume reduction, in which case a resulting large eruption would be the consequence (not the cause) of the collapse. I also show that ring-fault dip partly controls the size and intensity (volumetric flow or effusion rate) of the eruption. If the ring-fault dips inward (a normal fault), the displacement is ‘stable’, the volumetric flow rate (intensity) remains essentially constant during the collapse, and the magma chamber remains active following the collapse. By contrast, if the ring-fault dips outward (a reverse fault), the displacement is ‘unstable’, the volumetric flow rate normally increases dramatically during the collapse, and the magma chamber may be entirely destroyed during the collapse. |
DS201506-0271 2015 | Gueydan, F., Pitra, P., Afiri, A., Poujol, M., Essaifi, A., Paquette, J-L. | Oligo-Miocene thinning of the Beni Bousera peridotites and their Variscan crustal host rocks, Internal Rif, Morocco. | Tectonics, Vol. 34, pp.1244-1268. | Africa, Morocco | Peridotite |
DS201512-1922 2015 | Guha, A., Kumar, K.V., Ravi, S., Dhananjaya Rao, E.N. | Reflectance spectroscopy of kimberlites - in parts of Dharwar Craton, India. | Arabian Journal of Geosciences, Vol. 8, no. 11, pp. 9373-9388. | India | Deposit - Narayanpet |
| Abstract: In the present study, an attempt was made to analyse the reflectance spectra of kimberlites to evaluate its potential as key in remote sensing based spatial mapping. The spectral profiles of kimberlite samples were collected within the visible-near infrared-shortwave infrared (VNIR-SWIR) electromagnetic domain. In this regard, we analysed the reflectance spectra of three kimberlite pipes (having variable mineralogy) of Narayanpet kimberlite field (NKF) based on the comparative analysis of spectral features of kimberlite samples with the spectral features of their dominant constituent minerals. The relative abundances of each of the constituent minerals were confirmed using semiquantitative mineralogical data from X-ray diffraction analysis. This was supplemented with petrographical data as reference. We found that the absorption features imprinted in the reflectance spectra of kimberlites were mineralogically sensitive. These spectral features were imprinted by spectral features of serpentine, olivine, and calcite depending on the relative dominance of these minerals in kimberlites. With regard to understand the spectral behaviour of weathered residue of kimberlite for targeting buried kimberlite, we also attempted a comparative analysis of spectral profiles of in-situ soil developed above the pipes with the spectra of respective kimberlites in NKF area. While comparing aforementioned spectra, it was observed that the spectral signatures of NKF kimberlites were broadly translated to the in-situ soil. Further, we compared the spectral profiles of selected NKF kimberlites with the spectra of three distinct kimberlite pipes of Wajrakarur kimberlite field (WKF) characterised with similar mineralogy with respect to the selected NKF pipes. Relative dominance of constituent minerals (i.e., serpentine, olivine, calcite, etc.) in these pipes was taken as reference to identify the mineralogical similarity of the pipes of both the field. It was observed that the spectral profiles of NKF and WKF kimberlites were highly correlated with regard to wavelength of diagnostic absorption features. Finally, we also made an attempt to understand the effect of spectral mixing, in spectral separation of kimberlites and associated granite-granodiorite gneiss (i.e., Dharwar Gneiss). It was seen that the spectral contrast of kimberlite and gneiss was dependent on the relative size of the pipe with respect to pixel or ground sampling diameter of spectral data acquisition. Study confirmed the diagnostic nature of reflectance spectra of pipes along with their mineralogical sensitiveness and spatial integrity. It also highlighted how spectral mixing can influence the spectral feature based remote detection of kimberlites. |
DS201511-1838 2007 | Guidolin, M., La Ferrara, E. | Diamonds are forever, war is not: is conflict bad for private firms? | The American Economic Review, Vol. 97, 5, pp. 1978-1993. | Global | Economics |
| Abstract: This paper studies the relationship between civil war and the value of firms in a poor, resource abundant country using microeconomic data for Angola. We focus on diamond mining firms and conduct an event study on the sudden end of the conflict, marked by the death of the rebel movement leader in 2002. We find that the stock market perceived this event as “bad news” rather than "good news" for companies holding concessions in Angola, as their abnormal returns declined by 4 percentage points. The event had no effect on a control portfolio of otherwise similar diamond mining companies. This finding is corroborated by other events and by the adoption of alternative methodologies. We interpret our findings in the light of conflict-generated entry barriers, government bargaining power and transparency in the licensing process. |
DS201503-0146 2015 | Guzmics, T., Zajacz, Z., Mitchell, R.H., Szabo, C., Walle, M. | The role of liquid-liquid immiscibility and crystal fractionation in the genesis of carbonatite magmas: insights from Kerimasi melt inclusions. | Contributions to Mineralogy and Petrology, Vol. 169, 18p. | Africa, Tanzania | Carbonatite |
| Abstract: We have reconstructed the compositional evolution of the silicate and carbonate melt, and various crystalline phases in the subvolcanic reservoir of Kerimasi Volcano in the East African Rift. Trace element concentrations of silicate and carbonate melt inclusions trapped in nepheline, apatite and magnetite from plutonic afrikandite (clinopyroxene-nepheline-perovskite-magnetite-melilite rock) and calciocarbonatite (calcite-apatite-magnetite-perovskite-monticellite-phlogopite rock) show that liquid immiscibility occurred during the generation of carbonatite magmas from a CO2-rich melilite-nephelinite magma formed at relatively high temperatures (1,100 °C). This carbonatite magma is notably more calcic and less alkaline than that occurring at Oldoinyo Lengai. The CaO-rich (32-41 wt%) nature and alkali-"poor" (at least 7-10 wt% Na2O + K2O) nature of these high-temperature (>1,000 °C) carbonate melts result from strong partitioning of Ca (relative to Mg, Fe and Mn) in the immiscible carbonate and the CaO-rich nature (12-17 wt%) of its silicate parent (e.g., melilite-nephelinite). Evolution of the Kerimasi carbonate magma can result in the formation of natrocarbonatite melts with similar composition to those of Oldoinyo Lengai, but with pronounced depletion in REE and HFSE elements. We suggest that this compositional difference results from the different initial parental magmas, e.g., melilite-nephelinite at Kerimasi and a nephelinite at Oldoinyo Lengai. The difference in parental magma composition led to a significant difference in the fractionating mineral phase assemblage and the element partitioning systematics upon silicate-carbonate melt immiscibility. LA-ICP-MS analysis of coeval silicate and carbonate melt inclusions provides an opportunity to infer carbonate melt/silicate melt partition coefficients for a wide range of elements. These data show that Li, Na, Pb, Ca, Sr, Ba, B, all REE (except Sc), U, V, Nb, Ta, P, Mo, W and S are partitioned into the carbonate melt, whereas Mg, Mn, Fe, Co, Cu, Zn, Al, Sc, Ti, Hf and Zr are partitioned into the silicate melt. Potassium and Rb show no preferential partitioning. Kerimasi melt inclusions show that the immiscible calcic carbonate melt is strongly enriched in Sr, Ba, Pb, LREE, P, W, Mo and S relative to other trace elements. Comparison of our data with experimental results indicates that preferential partitioning of oxidized sulfur (as SO4 2?), Ca and P (as PO4 3?) into the carbonate melt may promote the partitioning of Nb, Ta, Pb and all REE, excluding Sc, into this phase. Therefore, it is suggested that P and S enrichment in calcic carbonate magmas promotes the genesis of REE-rich carbonatites by liquid immiscibility. Our study shows that changes in the partition coefficients of elements between minerals and the coexisting melts along the liquid line of descent are rather significant at Kerimasi. This is why, in addition to the REE, Nb, Ta and Zr are also enriched in Kerimasi calciocarbonatites. We consider significant amounts of apatite and perovskite precipitated from melilite-nephelinite-derived carbonate melt as igneous minerals can have high LREE, Nb and Zr contents relative to other carbonatite minerals. |
DS201501-0013 2015 | Gysi, A.P., Willams-Jones, A.E. | The thermodynamic properties of Bastnasite-(Ce) and parisite-(Ce). | Chemical Geology, Vol. 392, pp. 87-101. | | REE |
DS201507-0314 2015 | Hacker, B.R., Kelemen, P.B., Behn, M.D. | Continental lower crust. | Annual Review of Earth and Planetary Sciences, Vol. 43, pp. 167-205. | Mantle | Subduction |
DS201512-1923 2015 | Haiblen, A.M., Ward, B.C., Normandeau, P.X., Prowse, N.D. | Glacial history and landform genesis in the Lac de Gras area and implications for kimberlite drift prospecting. | 43rd Annual Yellowknife Geoscience Forum Abstracts, abstract p. 43. | Canada, Northwest Territories | Geomorphology |
| Abstract: During the last glaciation, bedrock was eroded, transported and deposited by the Laurentide Ice Sheet across much of Canada. The complex ice and meltwater processes that resulted in sediment deposition are not completely understood. In the central Slave Craton, Northwest Territories, glacial sediments overly many diamond-bearing kimberlites. Diamond deposits in the Lac de Gras area were discovered in the early 1990s by drift prospecting. To better interpret drift prospecting datasets a more thorough understanding of the detailed glacial history of the area is required. We spent six weeks in the Lac de Gras area in summer 2015. Field mapping was complimented by a number of other techniques to elucidate the glacial history of the area. Enigmatic landforms were examined in detail and pits were dug to examine their sedimentology. Samples of matrix material were collected to compare grain size distribution between different sediment types. Pebble counts were done to consider sediment provenance. We also collected ground-penetrating radar profiles to look for stratified sediments within enigmatic mounds. High-resolution orthophotos and a one metre LiDAR digital elevation model of the area, obtained by Dominion Diamond Ekati Corporation, have also been used to investigate landform genesis and the glacial history of the area. In the Lac de Gras area many meltwater corridors can be identified in the high-resolution imagery. These corridors are typically 300-1500 m wide and form dendritic networks. Between the corridors, sandy till of varying thickness overlies bedrock. Within corridors, glaciofluvial landforms and scoured bedrock are common. Also associated with corridors are many mounds of enigmatic origin. These mounds commonly occur in groups and are typically 20-100 m wide and rise 5-15 m above the surrounding area. They are usually composed of an unstratified to poorly-stratified sandy diamicton containing no clay and minor silt. Matrix grain size distribution and pebble lithology results from some mounds are similar to those of nearby regional till. However, patches of well-stratified sediments, exhibiting laminated silts as well as climbing ripples in sand, do exist on parts of some mounds. GPR data suggests that these patches are discontinuous, and that the majority of mounds are composed largely of sandy diamicton. Variation in the sedimentology of the mounds does not appear to be related to variations in mound morphology. It is likely that the majority of the glaciofluvial sediments in the Lac de Gras area were deposited during the final stages of ice retreat across the area when meltwater volumes were high. We suggest that the corridors were formed by subglacial meltwater flow. This is because glaciofluvial deposition almost exclusively occurs within corridors, very little till is found within corridors and the corridors have an undulating elevation profile in the direction of ice flow. Water must have played a role in the deposition of the well-stratified patches of sediment found on some mounds, however, the mounds may not be solely the product of subglacial meltwater flow. A thorough understanding of sediment transport and depositional processes is critical if kimberlite indicator mineral data is to be accurately interpreted. |
DS201509-0398 2015 | Hainschwang, T., Notari, F. | The first undisclosed colourless CVD synthetic diamond discovered in a parcel of natural melee sized diamonds. | The Journal of Gemmology, Vol. 334, 6, pp. 518-522. | Technology | Synthetics |
| Abstract: During the March 2015 Diamond Show in Basel, Switzerland, a parcel of 6,000 melee-sized colourless diamonds was analysed using the GGTL Diamond Fluorescence Imaging (DFI) Laser+ fluorescence imaging and spectroscopy system. From the entire parcel, one sample stood out clearly with unusual fluorescence colours and distribution, combined with a photoluminescence spectrum that clearly indicated it was a synthetic diamond grown by chemical vapour deposition (CVD). |
DS201503-0147 2014 | Hainschwang, T., Notari, F., Vadaszi, E. | The Rhodesian Star: an exceptional asteriated diamond. | The Journal of Gemmology, Vol. 34, 4, pp. 306-315. | Africa, Zimbabwe | Diamonds notable |
DS201503-0148 2014 | Hainschwang,T. | Diamants de type 1b: relations entre les proprietes physiques et gemmologiques des diamants contenant de l'Azote Isole. | Thesis, University of Nantes, France., In French * reference only | Technology | Nitrogen |
DS201512-1924 2015 | Hallis, L.J., Huss, G.R., Nagashima, K., Taylor, G.J., Halldorsson, S.A. | Evidence of primordial water in Earth's deep mantle. | Science, Vol. 350, 6252 Nov. 13, pp. 795-797. | Mantle | Water |
| Abstract: The hydrogen-isotope [deuterium/hydrogen (D/H)] ratio of Earth can be used to constrain the origin of its water. However, the most accessible reservoir, Earth’s oceans, may no longer represent the original (primordial) D/H ratio, owing to changes caused by water cycling between the surface and the interior. Thus, a reservoir completely isolated from surface processes is required to define Earth’s original D/H signature. Here we present data for Baffin Island and Icelandic lavas, which suggest that the deep mantle has a low D/H ratio (?D more negative than -218 per mil). Such strongly negative values indicate the existence of a component within Earth’s interior that inherited its D/H ratio directly from the protosolar nebula. |
DS201506-0272 2015 | Hamling, I.J., Wallace, L.M. | Silent triggering: aseismic crustal faulting induced by a subduction slow slip event. | Earth and Planetary Science Letters, Vol. 421, pp. 13-19. | Mantle | Subduction |
DS201510-1771 2015 | Hammouda, T., Keshav, S. | Melting in the mantle in the presence of carbon: review of experiments and discussion on the origin of carbonatites. | Chemical Geology, in press available | Mantle | Carbonatite |
| Abstract: Carbon emission at volcanic centers requires a constant balance between output (mostly by volcanism, either at plate boundaries or intraplate) and input (mostly at trench settings) of carbon from and to the Earth's mantle. The form of carbon that resides in the mantle is controlled by depth (pressure) and oxygen fugacity, the latter in turn depending on the depth and the concentration of iron in the mantle. In the shallow, lithospheric mantle, carbon is likely to be present in the oxidized form of CO2 (except under cratons where carbon is reduced to graphite or diamond). Below approximately 90 km, in the asthenosphere, the oxidized form of carbon is carbonate, either mineral or melt, depending on the thermal regime. At depths greater than approximately 150 km, the asthenospheric mantle is too reducing for carbon to stay in its oxidized form and only diamond is present, unless there is sufficient hydrogen to form reduced C-H fluids. Hence, the region located in the depth range of 90 to 150 km deep is where carbonatitic melts can most likely be produced and impregnate the surrounding mantle through metasomatism. The upper bound of this region is called the carbonate ledge. This limit prevents carbonate (either solid or molten) from ascending because of degassing and CO2 liberation. The lower bound is a redox front where redox melting (that is, melting caused by oxidation) may take place in an ascending portion of carbon-containing mantle. Carbonatite eruptions and presence of carbonate mineral inclusions in deep-seated diamonds provide evidence that these boundaries can be trespassed in some cases.
An analysis of the experimental data that has bearing on silicate melting in the presence of carbon further shows that the carbonate ledge is a melting curve with a negative or flat Clapeyron (dP/dT) slope. In the carbonated ultrabasic (peridotite) systems, the carbonate ledge is located between ~ 2-3 GPa. The ledge divides the pressure-temperature space into a region of low-pressure silicate melt production, and a high-pressure region where carbonatites can be produced. Carbonatitic melts in equilibrium with mantle peridotite have compositions close to dolomitic (approximately equal amounts of Ca and Mg) with a general trend of becoming markedly more magnesian with increasing pressure. Calcic carbonatites may be stable at pressures < 2 GPa if clinopyroxene is absent. At mantle transition zone pressure range, there seems to be a melting temperature decrease (negative fusion slope), which may be caused by the stabilization of majoritic garnet.
The carbonated basic (broadly eclogitic) system is more complex than the peridotitic one, because of the strong control of bulk silicate composition on melting temperatures, and hence, on melt composition. In carbonated eclogite systems, we propose that the effect of bulk composition upon all observed features can perhaps be related to silica super-saturation, or lack thereof. In some cases, high calcium (> 80 mol% CaCO3) melts can be produced, making the melting of carbonated eclogites an appealing scenario for the genesis of calcio-carbonatites in the Earth's mantle. Comparison with modeled pressure-temperature paths of subducted oceanic lithosphere shows that fusion of carbonated eclogite at depths shallower than 200 km should be expected for hot (Cascadian-type) subduction thermal regimes. On the other hand, in the case of cooler thermal regimes (Honshu-type, for instance), subducted carbonates may be stable to greater depths in Earth at trench settings, depending on the bulk composition of the system.
Furthermore, high-pressure experiments show evidence of a continuum among carbonatitic, kimberlitic, melilititic, and basaltic liquids, for increasing melting degree of carbonated peridotite. This continuum has not been documented in the case of fusion of carbonated eclogite. It may be present, however, when certain sediments are fused, although the silicate melts are granitic to rhyodacitic instead of being kimberlitic in composition. Additional high-pressure work on phase relations in the simple binary system CaCO3-MgCO3 and specific focus on oxide solubility in the vapor phase have the potential to further clarify phase relations on complex silicate-carbonate systems at mantle conditions. |
DS201510-1772 2015 | Hand, E. | Mantle plumes seen rising from Earth's core. | Science, Vol. 349, 6252, pp. 1032-1033. | Mantle | Plume |
| Abstract: Mantle plumes, tubes of hot rock rising from Earth's core, have come into focus, ending a more than 40-year-long debate. The result comes from a sophisticated MRI-like tomographic model that used 273 large earthquakes to illuminate the interior of Earth. It revealed as many as 28 plumes, many of them underneath known volcanic hot spots at Earth's surface. The plumes are fatter than expected, which means that they carry more heat away from Earth's core, an indication that plumes are important for cooling the planet. The model also shows that the plumes bend at a depth of 1000 kilometers, which could indicate an undiscovered mineral phase transition in the lower mantle that makes it less stiff. |
DS201512-1925 2015 | Hand, E. | How buried water makes diamonds and oils. | Science, Vol. 350, 6261, pp. 613-614. | Technology | Diamond genesis |
| Abstract: Under high pressures, water can react with surrounding rock to make diamonds and oil. These are just two consequences of a new picture of water's versatile chemistry in the mantle. The Deep Earth Water model is showing that, under extreme pressures down to 200 kilometers, water can dissolve many ions and host unexpected new reactions. It is replacing a geochemical framework, published in 1981, which made predictions for water-rock interactions, but only down to 15 kilometers. The idea that oil can be made from water and rock in the mantle is controversial, because it has long been assumed that oil arises through the compaction and burial of organic matter. |
DS201511-1839 2015 | Hansen, V.L. | Impact origin of Archean cratons. | Lithosphere, Vol. 7, pp. 563-578, | Mantle | Impacts |
| Abstract: Earth was a completely different planet more than 2.5 billion years ago. Little is known about this critical time when cratonic continental seeds formed; life emerged; and precious mineral resources concentrated. Our knowledge is limited because plate tectonic processes destroyed most of this early record. In contrast, Earth's sister, Venus -- similar in size, density, bulk composition, and distance from the Sun -- never developed plate tectonics. Venus also lacks a water cycle. Like siblings, Venus and Earth were most similar in their youth; however, Venus preserves a more complete geological record of its infancy, including both exogenic and endogenic features. Applying clues from Venus, Vicky L. Hansen proposes a new hypothesis for the formation of Earth's cratons. Large bolides pierced early thin lithosphere causing massive partial melting in the ductile mantle; melt escaped upward, forming cratonic crust; meanwhile strong, dry, buoyant melt residue formed cratonic roots, serving as unique buoyant life preservers during future plate-tectonic recycling. |
DS201511-1840 2015 | Harada, Y., Hishinuma, R., Terashima, C., Uetsuka, H., Nakata, K., Kondo, T., Yuasa, M., Fujishima, A. | Rapid growth of diamond and its morphology by in-liquid plasma CVD. | Diamond and Related Materials, in press available, 16p. | Technology | Synthetics |
| Abstract: Diamond synthesis and its morphology by in-liquid plasma chemical vapor deposition (CVD) method are investigated in this study. Diamond films were grown on Si substrates from mixed alcohol solution. Very high growth rate of 170 ?m/h was achieved by this method. Microcrystalline and nanocrystalline diamond films were formed in different conditions. In the case of microcrystalline film, the shapes of diamond grains depend on the location in the film. All morphological differences in this study can be explained by the same mechanism of conventional gas phase CVD method. It means diamond morphology by in-liquid plasma CVD method can be controlled by process parameters as well as gas phase CVD method. |
DS201512-1926 2015 | Hardman, M.F., Stachel, T., Pearson, D.G., Kinakin, Y.B., Bellinger, J. | Improving the utility of eclogitic garnet in diamond exploration - examples from Lac de Gras and worldwide localities. | 43rd Annual Yellowknife Geoscience Forum Abstracts, abstract p. 47. | Canada, Northwest Territories | Garnet chemistry |
| Abstract: In diamond exploration, the use of compositional data to identify diamond-related peridotitic xenocrysts has long been a widely used and powerful tool. In contrast, the application of similar methods to eclogitic garnet chemistry remains a challenge. The inability to unequivocally classify certain “eclogitic” garnet compositions as either mantle- or crust-derived implies that a high abundance of lower-crustal garnets will increase diamond-exploration expenditures by introducing a number of “false positives.” Revising existing classification schemes (e.g., Schulze, 2003) to reduce the abundance of “false positives” may, however, increase the number of “false negatives” through the misclassification of mantle-derived garnets as crustal. This study presents new geochemical and petrographical data for garnet and clinopyroxene from 724 kimberlite-hosted, crust- and mantle-derived xenoliths from localities worldwide, with a focus on samples whose lithology is constrained petrographically, rather than single mineral grains from concentrate. Mantle samples are primarily eclogitic and pyroxenitic, as constrained by mineral assemblage and garnet and clinopyroxene mineral chemistry, while crustal samples are dominantly plagioclase-bearing garnet-granulites. For those localities where an established geothermal gradient is available from literature resources, garnet-clinopyroxene pairs are employed in the estimation of pressure-temperature conditions of equilibration through the iterative coupling of the Krogh (1988) geothermometer and the relevant geothermal gradient. Our preliminary results suggest that closure temperatures for Fe-Mg exchange exceed the temperatures of residence of many lower-crustal samples, as geotherm-based calculated pressures of equilibration exceed the apparent stability of plagioclase (see Green and Ringwood, 1972). Comparison of equilibration pressures with sodium contents in garnet for mantle-derived samples (the diamond-facies criterion of Gurney, 1984) shows a positive correlation at localities for which an adequate range of pressures is observed (e.g., the Diavik mine). Other populations, such as mantle eclogitic garnets from Roberts Victor, plot at a much more restricted range of pressures and hence fail to demonstrate this correlation; instead, these samples may reflect the influence of a broader range of bulk-compositions, providing varying amounts of sodium to their constituent garnets. The results presented here demonstrate clearly that garnets from mantle- and crust-derived samples show significant overlap in geochemical character, for example in garnet Ca# vs. Mg# space (discrimination diagram of Schulze, 2003), where approximately 66% of our crust-derived garnet analyses plot in the “mantle” field. This percentage varies among locations. A selection of particularly high-Mg#, low-Ca# garnets derived from crustal, plagioclase-bearing lithologies in this study highlights the potential for crust-mantle confusion, as these garnets have Mg# in-excess of many mantle-derived eclogitic/pyroxenitic garnets. As a consequence, Fe-Mg-Ca-based classifications alone cannot reliably discriminate mantle and crustal garnets. The next step in this project will be to obtain trace element data for the entire sample suite. This will allow us to test the Li-geobarometer of Hanrahan et al. (2009) for eclogites and to search for trace element signatures that can be used as robust indicators of a diamond-facies origin of eclogitic garnets. Trace element data will also be employed in the refinement of the crust/mantle division discussed above. |
DS201507-0315 2015 | Harlow, G.E., Tsujimori, T., Sorensen, SS. | Jadeites and plate tectonics. | Annual Review of Earth and Planetary Sciences, Vol. 43, pp. 105-138. | Mantle | Jadeites |
DS201511-1841 2015 | Harris, J.R., Grunsky, E., Behnia, P., Corrigan, D. | Dat a and knowledge-driven mineral prospectivity maps for Canada's north. (**note for Au ) | Ore Geology Reviews, Vol. 71, pp. 788-803. | Canada, Nunavut, Melville Peninsula | GIS. IAS |
| Abstract: Data- and knowledge-driven techniques are used to produce regional Au prospectivity maps of a portion of Melville Peninsula, Northern Canada using geophysical and geochemical data. These basic datasets typically exist for large portions of Canada's North and are suitable for a "greenfields" exploration programme. The data-driven method involves the use of the Random Forest (RF) supervised classifier, a relatively new technique that has recently been applied to mineral potential modelling while the knowledge-driven technique makes use of weighted-index overlay, commonly used in GIS spatial modelling studies. We use the location of known Au occurrences to train the RF classifier and calculate the signature of Au occurrences as a group from non-occurrences using the basic geoscience dataset. The RF classification outperformed the knowledge-based model with respect to prediction of the known Au occurrences. The geochemical data in general were more predictive of the known Au occurrences than the geophysical data. A data-driven approach such as RF for the production of regional Au prospectivity maps is recommended provided that a sufficient number of training areas (known Au occurrences) exist. |
DS201508-0356 2015 | Harvey, J., Konig, S., Luguet, A. | The effects of melt depletion and metasomatism on highly siderophile and strongly chalcophile elements: S-Se-Te-Re-PGE systematics of peridotite xenoliths from Kilbourne Hole, New Mexico. | Geochimica et Cosmochimica Acta, Vol. 166, pp. 210-233. | United States, New Mexico, Colorado Plateau | Peridotite, xenoliths |
DS201508-0357 2015 | Hassan, R., Flament, N., Gurnis, M., Bower, D.J., Muller, D. | Provenance of plumes in global convection models. | Geochemistry, Geophysics, Geosystems: G3, Vol. 16, 5m pp. 1465-1489. | Africa | Convection |
DS201511-1842 2015 | Hazen, R.M., Hystad, G., Downs, R.T., Golden, J.J., Pires, A.J., Grew, E.S. | Earth's missing minerals. | American Mineralogist, Vol. 100, pp. 2344-2347. | Technology | Mineralogy |
| Abstract: Recent studies of mineral diversity and distribution lead to the prediction of >1563 mineral species on Earth today that have yet to be described-approximately one fourth of the 6394 estimated total mineralogical diversity. The distribution of these "missing" minerals is not uniform with respect to their essential chemical elements. Of 15 geochemically diverse elements (Al, B, C, Cr, Cu, Mg, Na, Ni, P, S, Si, Ta, Te, U, and V), we predict that approximately 25% of the minerals of Al, B, C, Cr, P, Si, and Ta remain to be described - a percentage similar to that predicted for all minerals. Almost 35% of the minerals of Na are predicted to be undiscovered, a situation resulting from more than 50% of Na minerals being white, poorly crystallized, and/or water soluble, and thus easily overlooked. In contrast, we predict that fewer than 20% of the minerals of Cu, Mg, Ni, S, Te, U, and V remain to be discovered. In addition to the economic value of most of these elements, their minerals tend to be brightly colored and/or well crystallized, and thus likely to draw attention and interest. These disparities in percentages of undiscovered minerals reflect not only natural processes, but also sociological factors in the search, discovery, and description of mineral species. |
DS201502-0061 2015 | He, L. | Thermal regime of the North Chin a craton: implications for craton destruction. | Earth Science Reviews, Vol. 140, pp. 14-26. | China | Geothermometry |
DS201508-0358 2015 | He, X-F., Santosh, M., Zhang, Z-M., Tsunogae, T., Chetty, T.R.K., Ram Moham, M., Anbazhagan | Shonkinites from Salem, southern India: implications for Cryogenian alkaline magmatism in rift related setting. | Journal of Asian Earth Sciences, in press available | India | Shonkinites |
DS201504-0201 2015 | Heaman, L.M., Pell, J., Grutter, H.S., Creaser, R.A. | U-Pb geochronology and Sr/Nd isotope compositions of groundmass perovskite from the newly discovered Jurassic Chidliak kimberlite field, Baffin Island, Canada. | Earth and Planetary Science Letters, Vol. 415, April pp. 183-189. | Canada, Nunavut, Baffin Island | Deposit - Chidliak |
DS201506-0273 2015 | Herzog, F.A. | The potential of a portable EDXRF spectrometer for gemmology. ( not specific to diamond) | The Journal of Gemmology, Vol. 34, 5, pp. 404-418. | Technology | Spectroscopy |
DS201501-0014 2015 | Hetman, C. | Canadian diamonds: past, present and future. | PDAC 2015, 1p. Abstract | Canada | History |
DS201503-0149 2015 | Hill, P.J.A., Kopylova, M., Russell, J.K. | Mineralogical controls on garnet composition in the cratonic mantle. | Contributions to Mineralogy and Petrology, Vol. 169, 20p. | Mantle | Garnet mineralogy |
DS201512-1927 2015 | Hiyate, A. | Botswana beckons. Prolific diamond nation attracts explorers. | Diamonds in Canada Magazine, Northern Miner, Nov. pp. 14-17. | Africa, Botswana | Overview of companies |
DS201502-0062 2014 | Hoag, H. | Earth's deep crust could support Wide spread life. | Nature, Dec. 23, 1p. | Mantle | Microbial ecosystems |
DC201511-2385 2015 | Honey Badger Exploration Inc. | Honey Badger Exploration receives TSX-V approval for LG diamonds project. | Honey Badger Exploration Inc., Oct. 22, 1p. | Canada, Quebec, James Bay Lowlands | News item - press release |
DC201512-2434 2015 | Honey Badger Exploration Inc. | Honey Badger exploration identifies priority targets at its LG diamonds project. | Honey Badger Exploration Inc., Nov. 19, 2p. | Canada, Quebec | News item - press release |
DS201509-0399 2015 | Hongsresawat, S., Panning, M.P., Russo, R.M., Foster, D.A., Monteiller, V., Chevrot, S. | USArray shear wave splitting shows seismic anisotropy from both lithosphere and asthenosphere. | Geology, Vol. 43, 8, pp. 667-670. | United States | Seismic -anisotropy |
| Abstract: North America provides an important test for assessing the coupling of large continents with heterogeneous Archean- to Cenozoic-aged lithospheric provinces to the mantle flow. We use the unprecedented spatial coverage of the USArray seismic network to obtain an extensive and consistent data set of shear wave splitting intensity measurements at 1436 stations. Overall, the measurements are consistent with simple shear deformation in the asthenosphere due to viscous coupling to the overriding lithosphere. The fast directions agree with the absolute plate motion direction with a mean difference of 2° with 27° standard deviation. There are, however, deviations from this simple pattern, including a band along the Rocky Mountain front, indicative of flow complication due to gradients in lithospheric thickness, and variations in amplitude through the central United States, which can be explained through varying contributions of lithospheric anisotropy. Thus, seismic anisotropy may be sourced in both the asthenosphere and lithosphere, and variations in splitting intensity are due to lithospheric anisotropy developed during deformation over long time scales. |
DS201504-0202 2015 | Howarth, G.H., Sobolev, N.V., Pernet-Fisher, J.F., Ketcham, R.A., Maisano, J.A., Pokhilenko, L.N., Taylor, D. | 3-D X-ray tomography of Diamondiferous mantle eclogite xenoliths, Siberia: a review. | Journal of Asian Earth Sciences, Vol. 101, 1, pp. 39-67. | Russia | Deposit - Udachnaya |
DS201508-0359 2015 | Howell, D., Fisher, D., Piazolo, S., Griffin, W.L., Sibley, S.J. | Pink color in Type I diamonds: is deformation twinning the cause? | American Mineralogist, Vol. 100, pp. 1518-1527. | Australia, South America, Venezuela | Deposit - Argyle, Santa Elena |
DS201511-1843 2015 | Huang, J-H., Huang, F., Evans, L., Glasauer, S. | Vanadium: global (bio)geochemistry. | Chemical Geology, Vol. 417, pp. 68-89. | Mantle | Mineralogy |
| Abstract: Redox-sensitive transition group elements are involved in almost all fundamental geochemical processes. Of these elements, vanadium (V) contributes a particularly powerful tool to decipher the Earth's history and its link to extraterrestrial bodies. A comprehensive view of V includes the formation and interaction between the Earth's interior layers, the evolution of the Earth's surface to a habitable zone, biogeochemical cycling, and anthropogenic impacts on the environment. Tracing the geochemical behavior of V through the Earth's compartments reveals critical connections between almost all disciplines of Earth sciences. Vanadium has a history of application as a redox tracer to address the early accretion history of the Earth, to identify connections between the mantle and crust by subduction and melting, and to interpret past surface environments. The geochemical cycling of V from the deep Earth to the surface occurs through magmatism, weathering and digenesis, reflecting variations of fO2 and V species in different Earth compartments. Minerals form a link between deep Earth reservoirs of vanadium and surface environments, and the study of V in minerals has increased the understanding of V cycling. Finally, the exploitation of V has been increasing since the Industrial Revolution, and significant amounts of V have been released as a consequence into natural systems. Environmental concerns are promoting new areas of research to focus on V cycling between water, air, soil and sediment compartments. An increased understanding of V in all compartments, and knowledge of the processes that connect the compartments, is vital to tracing the fate of this intriguing element in natural systems. |
DS201502-0063 2014 | Huang, J-X., Li, P., Griffin, W.L., Xia, Q-K, Greau, Y., Pearson, N.J., O'Reilly, S.Y. | Water contents of Roberts Victor xenolithic eclogites: primary and metasomatic controls. | Contributions to Mineralogy and Petrology, Vol. 168, pp. 1092-1105. | Africa, South Africa | Deposit - Roberts Victor |
DS201502-0064 2015 | Huang, L., Du, Y., Chen, G. | GeoSegmenter: a statistically learned Chinese word segmenter for the geoscience domain. | Computers & Geosciences, Vol. 76, pp. 11-17. | Technology | Not specific to diamonds |
DS201506-0274 2015 | Hudgins, T.R., Mukasa, S.B., Simon, A.C., Moore, G., Barifaijo, E. | Melt inclusion evidence for CO2 rich melts beneath the western branch of the East African Rift: implications for long term storage of volatiles in the deep lithospheric mantle. | Contributions to Mineralogy and Petrology, Vol. 169, 5p. | Africa, East Africa | Basanites, Foidites |
DM201506-0783 2015 | Huffington Post | Ontario's only diamond mine and royalties paid in the province. Victor | Huffington Post, May 14, 3p. | Canada, Ontario | News item - De Beers |
DS201505-0251 2015 | Hwang, S-L., Shen, P., Chu, H-T., Yui, T-F., Lizuka, Y. | Origin of rutile needles in star garnet and implications for interpreation of inclusion textures in ultrahigh pressure metamorphic rocks. | Journal of Metamorphic Geology, Vol. Pp. 249-272. | Technology | UHP |
DS201508-0360 2015 | Hystad, G., Downs, R.T., Hazen, R.M. | Mineral species frequency distribution conforms to a large number of rare events model: prediction of Earth's missing minerals. | Mathematical Geosciences, Vol. 47, no. 6, pp. 647-661. | Technology | Not specific to diamonds but interesting reading! |
DS201507-0316 2015 | Ickert, R.B., Stachel, T., Stern, R.A., Harris, J.W. | Extreme 18O-enrichment in majorite constrains a crustal origin of transition zone diamonds. | Geochemical Perspectives Letters, 1, pp. 65-74. | Africa, South Africa | Deposit - Jagersfontein |
DS201505-0252 2015 | ICMM | Engaging with society - ICMM releases annual review 2014. | ICMM, March, 14p. Pdf | Global | CSR |
DS201509-0400 2015 | ICMM | The role of mining in Ghana's future. | ICMM, July 72p. | Africa, Ghana | Legal |
DS201512-1928 2015 | ICMM | Good practice guide to indigenous peoples and mining. | ICMM , pdf. 138p. | Global | CSR |
DS201503-0150 2015 | ICMM, Raw Materials Group, Oxford Policy Management | The role of mining in national economies. 2nd edition | ICMM, Oct. 56p. | Global | Economics |
DM201503-0784 2015 | Idex Magazine | So near yet so far … introduction to Zimbabwe diamond supplier. | Idex Magazine, Feb. pp. 36-38. | Africa, Zimbabwe | News item - history |
DM201503-0785 2015 | Idex Magazine | Zimbabwe diamond industry. | Idex Magazine, Feb. pp. 38-45. | Africa, Zimbabwe | News item - diamond industry |
DM201503-0786 2015 | Idex Magazine | Diamond - sector objectives. | Idex Magazine, Feb. pp. 46-51. | Africa, Zimbabwe | News item - legal |
DM201503-0787 2015 | Idex Magazine | Is the Marange party over? | Idex Magazine, Feb. pp. 52-61. | Africa, Zimbabwe | News item - Marange |
DM201503-0788 2015 | Idex Magazine | A century of Zimbabwe diamond exploration. | Idex Magazine, Feb. pp. 62-68. | Africa, Zimbabwe | News item - history |
DM201504-0789 2015 | Idex Magazine | The millennial generation.. Changing the way we buy. | Idex Magazine, March, pp. 36-64. | Global | News item - retail |
DM201505-0790 2015 | Idex Magazine | From clicks to bricks - Blue Nile. | Idex Magazine, Apr. pp. 38-45. | Global | News item - Blue Nile |
DM201505-0791 2015 | Idex Magazine | Get moving to mobile. | Idex Magazine, Apr. pp. 46-55. | Global | News item - online for consumers |
DM201505-0792 2015 | Idex Magazine | From on-line to in-store: could click and collect be the next big thing? | Idex Magazine, Apr. pp. 56-62. | Global | News item - online for consumers |
DM201507-0793 2015 | Idex Magazine | 2014: the year of confidence lost. | Idex Magazine, June pp. 38-43. | Global | News item - markets |
DM201507-0794 2015 | Idex Magazine | The 2014 diamond pipeline. | Idex Magazine, June pp. 44-66. | Global | News item - pipeline |
DM201509-0795 2015 | Idex Magazine | A splintering of the pipeline.. Publicity surrounding the Diamond Producers Association. | Idex Magazine, Aug. pp. 36-45. | Global | News item - pipeline |
DM201509-0796 2015 | Idex Magazine | Danger of product substitution… | Idex Magazine, Aug. pp. 46-53. | Technology | News item - Lab grown |
DM201509-0797 2015 | Idex Magazine | Lab-grown diamonds increase bargaining power. | Idex Magazine, Aug. pp. 54-66. | Technology | News item - synthetics |
DS201501-0015 2014 | Idex Magazine | Review of the year. | Idex Magazine, No. 296, December pp. 36-66. | Global | Industry - problems and highs and lows |
DS201501-0016 2014 | Idex Magazine | Idex & AdAmiA .. Launch of diamond investment product. | Idex Magazine, No. 296, December p. 21. ( 1p) | Global | AdAmia |
DS201506-0275 2015 | Idex Magazine | The missing gap, a bridge from gemology to reality. | Idex Magazine, No. 301, pp. 118-119. | Technology | Gemology |
DS201512-1929 2015 | Idex Magazine | 2015 Indian diamond industry Local pressures and global challenges. | Idex Magazine, No. 307, pp. 34-36. | India | Economics |
DS201512-1930 2015 | Idex Magazine | Return to generalized system of preferences. India | Idex Magazine, No. 307, pp. 37-43. | India | Economics |
DS201512-1931 2015 | Idex Magazine | Rough price stability will return prosperity to the Indian diamond industry. | Idex Magazine, No. 307, pp. 44-46. | India | Economics |
DM201501-0798 2014 | Idex Memo | Dull name, important task: generic marketing critical to industry's future. | Idexonline.com, Dec. 4, 1p. | Global | News item - markets |
DM201501-0799 2014 | Idex Memo | GIA battling crimes: suspends duplicate report service to prevent fraud. | Idexonline.com, Dec. 11, 2p. | Global | News item - GIA |
DM201501-0800 2014 | Idex Memo | Long path to recovery shows few signs of ending for Japan. | Idexonline.com, Dec. 19, 2p. | Japan | News item - economics |
DM201502-0801 2014 | Idex Memo | Year end reflections: the 95 year struggle to secure rough for beneficiation. | Idexonline.com, Dec. 25, 2p. | Global, India | News item - rough demand |
DM201502-0802 2015 | Idex Memo | New Year, old challenges. | Idexonline.com, Jan. 1, 2p. | Global | News item - demand |
DM201502-0803 2015 | Idex Memo | True Luxe ways. Study on luxury brands and their best customers. | Idexonline.com, Jan. 8, 1p. | Global | News item - markets |
DM201502-0804 2015 | Idex Memo | Modern family…. Tiffany's ad campaign. | Idexonline.com, Jan. 15, 2p. | Global | News item - Tiffany |
DM201502-0805 2015 | Idex Memo | A way with words… engagement marketing | Idexonline.com, Jan. 22, 1p. | Technology | News item - markets |
DM201503-0806 2015 | Idex Memo | Economics 101: a course on added value. | Idexonline.com, Jan. 29, 2p. | Technology | News item - economics |
DM201503-0807 2015 | Idex Memo | Synthetic diamond producer creates trade representative body prohibits the use of the 'S'-word. | Idexonline.com, Feb. 12, 8p. | Technology | News item - synthetics |
DM201503-0808 2015 | Idex Memo | Too much of a good thing? Re-used engagement rings. | Idexonline.com, Feb. 19, 1p. | Global | News items - engagements |
DM201504-0809 2015 | Idex Memo | Undisclosed lab-grown diamonds strike again. Surat | Idex Online, Feb. 26, 1p. | India | News item - synthetics |
DM201504-0810 2015 | Idex Memo | Is it just history repeating itself? ( promotion) | Idex Online, Mar. 12, 1p. | Global | News item - promoters |
DM201505-0811 2015 | Idex Memo | Just a little disruption… discusses DDI's approach and work to date. | Idex Online, Apr. 2, 1p. | Global | News item - DDI |
DM201505-0812 2015 | Idex Memo | If you have to pinpoint three factors from the diamond business affecting the retail world of fine jewelery, what would you pick? | Idex Online, Apr. 9, 1p. | Global | News item - jewellery |
DM201505-0813 2015 | Idex Memo | Going up or down: where are diamond prices really headed? | Idexonline.com, Apr. 16, 1p. | Global | News item - prices |
DM201505-0843 2015 | Idex Memo | Rocking the boat… Marques de Morais overview. | Idex Online, Mar. 26, 1p. | Africa, Angola | News item - legal |
DM201506-0814 2015 | Idex Memo | Taxing the Antwerp diamond industry into prosperity. | IdexOnline, Apr. 23. 3p. | Europe, Belgium | News item - legal |
DM201506-0815 2015 | Idex Memo | The year the industry lost confidence in its future. | IdexOnline, May 7, 3p. | Global | News item - economics |
DM201506-0816 2015 | Idex Memo | Yet another deception … undisclosed treatment of gems masking the inherent colour. | IdexOnline, May 14, 1p. | Technology | News item - GIA |
DM201506-0817 2015 | Idex Memo | When life gives you lemons. | IdexOnline, May 21, 1p. | Technology | News item - economics |
DM201507-0818 2015 | Idex Memo | Retail jewelry prices down: demand down - where's the logic? Big picture issues and obstacles discussed. | Idex Online, May 28, 1p. | Global | News item - retail |
DM201507-0819 2015 | Idex Memo | A tagline forever … De Beers .. | Idexonline, June 11, 1p. | Global | News item - De Beers |
DM201507-0820 2015 | Idex Memo | Antwerp Lab discovers and reverses undisclosed temporary color: IGI's findings alarmingly similar to fraudulent treatements exposed by GIA. | idexonline, DIB Vol. 30, no. 858, June 16, 6p. | Technology | News item - treatments |
DM201507-0821 2015 | Idex Memo | The myth of marketing to millennials. ( their dollars are fickle) | Idex Online, June 25, 1p. | Global | News item - markets |
DM201508-0822 2015 | Idex Memo | Gemfields India film explores mystery of rubies. | Idex online, July 14, 1/4p. | Africa, Madagascar | News item - Gemfields |
DM201508-0823 2015 | Idex Memo | No hard times for good ideas. | Idex online, July 16, 1p. | Global | News item - marketing |
DM201509-0824 2015 | Idex Memo | De Beers does not feel the love ( commentary on Kilalea's report). | Idex online, July 30, 1p. | United States | News item - De Beers |
DM201509-0825 2015 | Idex Memo | Why duty free is the next big retail arena. | Idex online, Aug. 6, 1p. | Global | News item - duty free |
DM201510-2041 2015 | Idex Memo | The never-ending conflict ( diamonds). | Idexonline, Aug. 27, 1p. | Africa, Central African Republic, Sierra Leone | News item - legal |
DM201510-2042 2015 | Idex Memo | Don't try to hide…. Websites keep a record of all your previous purchases, interests, credit card statements etc etc. | Idexonline, Sept. 17, 2p. | Technology | News item - websites |
DM201510-2043 2015 | Idex Memo | Betting on color…. Minion yellow. | Idexonline, Sept. 24, 1p. | Technology | News item - diamond colour |
DM201511-2141 2015 | Idex Memo | Is banning lab-grown diamonds really a victory? | Idex Online, Oct. 15, 1p. | Technology | News item - synthetics |
DM201511-2142 2015 | Idex Memo | She who controls the purse strings…. Affluent women.. Marketing to them. | Idex Online, Oct. 22, 1p. | Global | News item - markets |
DM201512-2249 2015 | Idex Memo | Call for a new generation of industry leadership. | Idex Online, Oct. 29, 1p. | Global | News item - economics |
DM201512-2250 2015 | Idex Memo | Shop until you drop on November 11 Singles Day .. China | Idex Memo, Nov. 11, 1p. | China | News item - markets |
DM201502-0826 2014 | Idex Online | Zimbabwe signs deal for polishing equipment with Indian firm Sahajanand Laser Technology Limited. | Idexonline.com, Dec. 31, 1p. | Africa, Zimbabwe, India | News item - Zimbabwe Diamond Technology Centre |
DM201502-0827 2015 | Idex Online | Indian trade bodies warn against mixing synthetics with natural diamonds. | Idexonline.com, Jan. 8, 1/4p. | India | News item - GJEPC |
DM201502-0828 2015 | Idex Online | Mbada diamonds turns to riot police to calm worker protests. | Idexonline.com, Jan. 8, 1/4p. | Africa, Zimbabwe | News item - Mbada |
DM201502-0829 2015 | Idex Online | South African youths to learn diamond polishing in Surat. | Idexonline.com, Jan. 12, 1/4p. | India | News item - polishing |
DM201504-0830 2015 | Idex Online | IDE plan to help Turkey develop diamond industry. | Idexonline.com, Mar. 22, 1/4p. | Europe, Turkey | News item - IDE |
DM201505-0841 2015 | Idex Online | Gemfields emerald production hits 9.9 million carats in Q3. | Idexonline.com, Apr. 15, 1p. | Africa, Zambia | News item - Gemfields |
DM201507-0831 2015 | Idex Online | De Beers's rough diamond sales for beneficiation reaches $ 1.5 billion in 2014. | Idex Online, June 2, 1/2p. | Global | News item - De Beers |
DM201507-0832 2015 | Idex Online | Fatality reported in Kimberley Diamonds Lerala mine. | Idexonline, June 11, 1/4p. | Africa, Botswana | News item - Kimberley Diamonds |
DM201507-0833 2015 | Idex Online | TACY's 2014 Diamond Pipeline: the year the industry lost confidence in its future. | Idex Online, June 11, 2p. Chart | Global | News item - Diamond pipeline |
DM201507-0844 2015 | Idex Online | De Beers satisfied with new Namibian sales agreement. | Idex Online, June 25, 1/4p. | Africa, Namibia | News tem - De Beers |
DM201508-0834 2015 | Idex Online | Sarine Technologies Galaxy System scans 10 millionth stone. | Idex online, July 2, 1/4p. | Technology | News item - Sarine |
DM201508-0835 2015 | Idex Online | Rio Tinto Diamonds has completed the sale of its two holdings in Zimbabwe. 78% interest in Murowa diamonds to RZ Murowa Holdings Limited ( Zimbabwean independent company) | Idex online, July 3, 1p. | Africa, Zimbabwe | News item - Rio Tinto |
DM201508-0836 2015 | Idex Online | Who wears the jewelry? ( women buying for themselves) | Idex online, July 9, 1p. | Global | News item - markets |
DM201509-0837 2015 | Idex Online | Rio Tinto diamond production +18 % in H1 2015. | Idex Online, Aug. 6, 1/4p. | Global | News item - Rio Tinto |
DM201509-0838 2015 | Idex Online | Researchers discover 20+ potential diamond deposits in Indian state of Telgana. Mahbubnagar district. | Idex Online, Aug. 11, 1/4p. | India | News item - Telgana |
DM201509-0839 2015 | Idex Online | Alrosa releases 2014 social and environmental report. | Idexonline.com, Aug. 27, 1/4p. | Russia | News item - Alrosa |
DM201509-0840 2015 | Idex Online | The government of Madhya Pradesh is planning to establish a Diamond Park Project in the commercial capital of Indore. | Idexonline.com, Aug. 25, 1/2p. | India, Madhya Pradesh | News item - processing |
DM201510-2044 2015 | Idex Online | The Hatton Garden Safe Deposit - appointed liquidators for it. | Idexonline, Aug. 28, 1p. | Europe, United Kingdom | News item - Hatton Garden Safe Deposit |
DM201510-2045 2015 | Idex Online | Alrosa's Zharkov emphasizes need to stabilize market at EEF ( Eastern Economic Forum). | Idexonline, Sept. 7, 1/2p. | Russia | News item - Alrosa |
DM201510-2046 2015 | Idex Online | Alrosa to drop rough prices by 10% at September sight. | Idexonline, Sept. 18, 1/4p. | Russia | News item - Alrosa |
DM201510-2047 2015 | Idex Online | Idex online DEF responds to Time Magazine article ( Blood Diamonds). Open letter "Diamonds do Good". | Idexonline, Sept. 13, 2p. | Global | News item - Time Magazine |
DM201511-2143 2015 | Idex Online | KDL secures another $ 2.2 million in debt finance. Lerala ( from Zhejiang Huitong Auction Co.) | Idex Online, Oct. 12, 1/4p. | Africa, Botswana | News item - Kimberley Diamonds |
DM201511-2144 2015 | Idex Online | Alrosa developing lab-grown diamond screening technology. | Idex Online, Oct. 15, 1/2p. | Technology | News item - synthetics |
DM201512-2251 2015 | Idex Online | Fusion/Hennig to tender 128 carat yellow diamond. Superkolong tailings plant | Idex Online, Nov. 5, 1/4p. | Africa, South Africa | News item - Fusion/Hennig |
DM201512-2252 2015 | Idex Online | Anglo American has made a number of changes …. De Beers Cleaver appointed group director - Strategy and Business development; Mostyn appointed executive head of Strategy and Corporate Affairs. | Idex Online, Nov. 11, 1/4p. | Global | News tem - Anglo American |
DM201512-2253 2015 | Idex Online | Botswana Diamonds reports $ 512,000 operating loss for 2015. | Idex Online, Nov. 19, 1/4p. | Africa, Botswana | News item - Botswana Diamonds |
DS201507-0317 2015 | Ignaov, P.A., Novikov, K.V., Shmonov, A.M., Razumov, A.N., Kilizhikov, O.K. | Comparative analysis of ore bearing structures in Maiskoe, Markha and Ozernoe kimberlite bodies at the Nakyn field, Yakutia. | Geology of Ore Deposits, Vol. 57, 2, pp. 111-117. | Russia | Deposit - Nakyn |
DS201506-0276 2015 | Ignatov, P.A., Novikov, K.V., Shmonov, A.M., Razumov, A.N., Kilizhikov, O.K. | Comparative analysis of ore-bearing structures in Maiskoe, Markha and Ozernoe kimberlite bodies at the Nakyn Field, Yakutia. | Geology of Ore Deposits, Vol. 57, 2, pp. 111-117. | Russia | Deposit - Nakyn |
DM201503-0842 2015 | IIa Technologies | Scientific luminaries see great potential for grown diamonds. Dr. Misra | Iia Technologies, Jan. 30, 1p. | Technology | News item - IIa Technologies |
DM201503-0845 2015 | Investing in African Mining Indaba | As South Africa loses its mining lustre, these countries are waiting to pounce, and some of the region's biggest players. DR Congo, Angola, Rwanda, Endiama | Investing in African Mining Indaba, Feb. 17, 3p. | Africa, South Africa | News item - review |
DS201509-0401 2015 | Ionov, D.A., Carlson, R.W., Doucet, L.S., Golovin, A.V., Oleinikov, O.B. | The age and history of the lithospheric mantle of the Siberian craton: Re-Os and PGE study of peridotite xenoliths from the Obnazhennaya kimberlite. | Earth and Planetary Science Letters, Vol. 428, pp. 108-119. | Russia, Siberia | Deposit - Obnazhennaya |
| Abstract: The formation age of the lithospheric mantle of the Siberian craton (one of the largest on Earth) is not well established; nearly all published whole-rock Re–Os data are for mantle xenoliths from a single kimberlite in the center of the craton (Udachnaya). We report Re–Os isotope and PGE concentration data for 19 spinel and garnet peridotite xenoliths from the Obnazhennaya kimberlite in the northeastern portion of the craton. Most samples in this study, and many Obnazhennaya peridotites in general, show a combination of relatively low Al2O3 (0.1–2%) with high CaO (1.4–4%) concentrations. Only four dunites and harzburgites in our sample suite have low contents of both Al2O3 and CaO (0.1–0.8%), but their relatively low Mg# (0.888–0.919) and highly variable Os concentrations (0.6–35 ppb) suggest they may have formed in melt migration channels rather than as residues of partial melt extraction. A group of six Ca-rich (2.0–3.2% CaO) peridotites yields the highest Re–Os model ages (mean TRD = 2.8 Ga, mean TMA = 3.5 Ga). Eight peridotites with low to moderate Al2O3 (<2%) and Mg# ?0.91, including three low-Ca harzburgites, yield lower Re–Os model ages (mean TRD = 1.9 Ga, mean TMA = 2.2 Ga). The remainder of the samples may not yield meaningful TRD ages because they are not refractory (Al2O3 >2.6% and/or Mg# ?0.90). We interpret these results as evidence for a two-stage formation of the lithospheric mantle. The peridotites formed at the two stages show very similar chemical compositions. The enrichment in Ca, which we attribute to widespread post-melting metasomatism by carbonate-rich melts, may have taken place either at the end of the Archean melting event, when at least one Ca–Al-rich peridotite was formed, or later. The combined Re–Os age data on xenoliths from Obnazhennaya and Udachnaya suggest that the lithospheric mantle beneath the Siberian craton was not formed in a single event, but grew in at least two events, one in the late Archean and the other in the Paleoproterozoic. This study further indicates that the formation of highly melt-depleted lithospheric mantle was not limited to the Archean, but continued well into the Paleoproterozoic when the Siberian craton was stabilized. |
DS201512-1932 2015 | Isaenko, S.I., Shumilova, T.G., Shevchuk, S.S. | Carbon matter in kimberlite rocks of the Charteskii Complex ( Subpolar Urals). | Doklady Earth Sciences, Vol. 464, 2, pp. 1062-1065. | Russia | Carbon |
| Abstract: Results of the study of carbon material (CM) discovered in kimberlite-like rocks of the Charteskii Complex (Subpolar Urals) are considered. It is shown that CM is represented by partially oxidized graphite and optically transparent amorphous CM (presumably diamond-like carbon). The data obtained are important for estimation of the diamond potential of this object, as well as for understanding of the new mechanism of the formation of diamond-like carbon and diamond. |
DS201502-0065 2014 | Isola, I., Mazzarini, F., Bonini, M., Cortiz, G. | Spatial variability of volcanic features in early-stage rift settings: the case of the Tanzanian divergence, East African Rift. | Terra Nova, Vol. 26, pp. 461-468. | Africa, Tanzania | Rifting, magmatism |
DS201511-1844 2015 | Ivanov, A.V. | Why volatiles are required for cratonic flood basalt volcanism: two examples from the Siberian craton. | Geological Society of America Special Paper, No. 514, pp. SPE514-19. | Russia, Siberia | Magmatism |
| Abstract: The Siberian craton was affected by flood basalt volcanism at least twice during the Devonian (Yakutsk-Vilyui province) and Permian-Triassic (Siberian province) periods. In both cases volcanism appeared as brief pulses of flood basalt eruptions, followed by kimberlitic (and lamproitic) emplacement. Pressure estimations for the kimberlite-entrained mantle xenoliths reflect that the lithosphere was 190-230 km thick at the time of the Devonian flood basalt volcanism. Differently from Devonian kimberlites, the majority of Triassic kimberlites are diamond free, but at least one Triassic kimberlite pipe and some lamproites are diamondiferous, suggesting that the Siberian lithosphere remained thick during the Permian-Triassic flood basalt volcanic activity. If both the lithosphere and the asthenosphere were volatile poor, thick cratonic lithosphere prevented melting even at an elevated geotherm. During the Paleozoic, Siberia was surrounded by subduction systems. The water deep cycle in association with fast subduction and slab stagnation in the mantle transition zone is proposed to cause fluxing of the asthenosphere by water plus other fluids via wet diapir formation in the mantle transition zone. Such diapirs started to melt in the asthenosphere beneath thick cratonic lithosphere, producing voluminous melts. Mafic melts probably accumulated beneath cratonic lithosphere and rapidly erupted on the surface in response to stress-induced drainage events, as assumed for some other cratonic flood basalts. |
DS201505-0242 2015 | 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 Africa | Fibrous diamonds |
DS201507-0318 2015 | 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. | Mantle | Magmatism |
DS201503-0151 2015 | Jakubec, J., Johnson, M. | The Jericho diamond mine - what happened? | Vancouver Kimberlite Cluster, Feb. 20, 1p. Abstract | Canada, Nunavut | Deposit - Jericho |
DS201504-0203 2015 | 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 subduction | Journal of Metamorphic Geology, Vol. 33, 5, pp. 495-512. | Europe, Slovenia | Subduction |
DM201502-0846 2015 | JCK online | De Beers CEO: we take new reports of undisclosed synthetics "very seriously". Mellier and need for marketing. | JCKOnline.com, Jan. 13, 3p. | Global | News item - De Beers |
DM201503-0847 2015 | JCK online | An anthropologist talks about why people want diamonds. | JCKOnline.com, Jan. 30, 2p. | Global | News item - markets |
DM201504-0848 2015 | JCK Online | Diamond Intelligence Breifs changing format. … briefing with in depth stories 12 times or more a year. Elininating the weekly news briefs at back of the newsletter which are available from other sources. | jckonline.com, Mar. 16, 1/2p. | Global | News item - DIB |
DS201511-1845 2015 | Jellinek, A.M., Jackson, M.G. | Connections between bulk composition, geodynamics and habitability of Earth. | Nature Geoscience, Vol. 8, pp. 587-593. | Mantle | Geodynamics |
| 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. |
DS201512-1934 2015 | 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, Iceland | Mantle 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. |
DS201503-0152 2015 | Jensen, S. | Diamonds beneath the Popigai crater - northern Russia. | Denver Geophysical Society, The Record, No. 3, Feb. pp. 3-5. | Russia | Popigai - rehash |
DS201509-0403 2015 | 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 available | Africa, West Africa | Geophysics - 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., Begg, G.C., Miller, M.S. | The geophysical signatures of the West African Craton. | Precambrian Research, in press available, 22p. | Africa, West Africa | Geophysics - 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. |
DS201507-0319 2015 | Jia, Y., Kerrich, R. | N isotope composition of the primitive mantle compared to diamonds. | Lithos, Vol. 233, pp. 131-138. | Mantle | Nitrogen - subduction |
DS201509-0404 2015 | Johnson, B., Goldblatt, C. | The nitrogen budget of Earth. | Earth Science Reviews, Vol. 148, pp. 150-173. | Mantle | Nitrogen |
| 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. |
DS201511-1846 2012 | 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 pdf | Canada, Northwest Territories | Microdiamonds - 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. |
DS201506-0277 2015 | Johnson, M.L. | Colour grading of synthetic moissanite. | The Journal of Gemmology, Vol. 34, 5, pp. 384-385. | Technology | Moissanite |
DS201510-1774 2015 | 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 Booth | Technology | Synthetic 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. |
DS201511-1847 2015 | Julian, B.R., Foulger, G.R., Hatfield, O., Jackson, S.E., Simpson, E., Einbeck, J., Moore, A. | Hotspots in hindsight. Mentions kimberlites | Geological Society of America Special Paper, No. 514, pp. SPE514-08. | Mantle | Hotspots |
| 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. |
DS201506-0278 2015 | 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. | Mantle | Core |
DS201503-0153 2014 | Kaban, M.K., Mooney, W.D., Cloetingh, S.A.P. | Density, temperature and composition of the North American lithosphere - new insights from a joint analysis of seismic, gravity and mineral physics data: 1. density structure of the crust and upper mantle. | Geochemistry, Geophysics, Geosystems: G3, Vol. 15, 12, pp. 4781-4807. | Mantle | Geophysics - seismic |
DS201511-1848 2015 | Kaban, M.K., Mooney, W.D., Petrunin, A.G. | Cratonic root beneath North America shifted by basal drag from the convecting mantle. | Nature Geoscience, Vol. 8, 10, pp. 797-800. | United States, Canada | Geophysics - seismics |
| Abstract: Stable continental cratons are the oldest geologic features on the planet. They have survived 3.8 to 2.5 billion years of Earth’s evolution1, 2. The key to the preservation of cratons lies in their strong and thick lithospheric roots, which are neutrally or positively buoyant with respect to surrounding mantle3, 4. Most of these Archaean-aged cratonic roots are thought to have remained stable since their formation and to be too viscous to be affected by mantle convection2, 3, 5. Here we use a combination of gravity, topography, crustal structure and seismic tomography data to show that the deepest part of the craton root beneath the North American Superior Province has shifted about 850?km to the west-southwest relative to the centre of the craton. We use numerical model simulations to show that this shift could have been caused by basal drag induced by mantle flow, implying that mantle flow can alter craton structure. Our observations contradict the conventional view of cratons as static, non-evolving geologic features. We conclude that there could be significant interaction between deep continental roots and the convecting mantle. |
DS201511-1849 2016 | Kalashnikov, A.O., Yakovenchuk, V.N., Pakhomovsky, Y.A.A., Bazai, A.V., Sokharev, V.A., Konopleva, N.G., Mikhailova, J.A., Goryainov, P.M., Ivanyuk, G.Yu. | Scandium of the Kovdor baddeleyite apatite magnetite deposit ( Murmansk region, Russia): mineralogy, spatial distribution, and potential source. | Ore Geology Reviews, Vol. 72, pp. 532-537. | Russia | Carbonatite |
DS201502-0066 2015 | Kalashnyk, A. | Regularities of spatial association of major endogenous uranium deposits and kimberlitic dykes in the uranium ore regions of the Ukrainian Shield. | Economic Geology Research Institute 2015, Vol. 17,, # 2872, 1p. Abstract | Russia, Ukraine | Kimberlite dykes |
DS201511-1850 2015 | Kaldos, R., Guzmics, T., Mitchell, R.H., Dawson, J.B., Milke, R., Szabo, C. | A melt evolution model for Kerimasi volcano, Tanzania: evidence from carbonate melt inclusions in jacupirangite. | Lithos, Vol. 238, pp. 101-119. | Africa, Tanzania | Carbonatite |
| Abstract: This study presents compositional data for a statistically significant number (n=180) of heated and quenched (recreated) carbonate melt inclusions trapped in magnetite and clinopyroxene in jacupirangite from Kerimasi volcano (Tanzania). On the basis of homogenization experiments for clinopyroxene-hosted melt inclusions and forsterite-monticellite-calcite phase relations, a range of 1000 to 900 °C is estimated for their crystallization temperatures. Petrographic observations and geochemical data show that during jacupirangite crystallization, a CaO-rich and alkali-"poor" carbonate melt (relative to Oldoinyo Lengai natrocarbonatite) existed and was entrapped in the precipitating magnetite, forming primary melt inclusions, and was also enclosed in previously crystallized clinopyroxene as secondary melt inclusions. The composition of the trapped carbonate melts in magnetite and clinopyroxene are very similar to the parental melt of Kerimasi calciocarbonatite; i.e., enriched in Na2O, K2O, F, Cl and S, but depleted in SiO2 and P2O5 relative to carbonate melts entrapped at an earlier stage and higher temperature (1050-1100 °C) during the formation of Kerimasi afrikandite. Significant compositional variation is shown by the major minerals of Kerimasi plutonic rocks (afrikandite, jacupirangite and calciocarbonatite). Magnetite and clinopyroxene in the jacupirangite are typically transitional in composition between those of afrikandite and calciocarbonatite. These data suggest that the jacupirangite represents an intermediate stage between the formation of afrikandite and calciocarbonatite. Jacupirangite most probably formed when immiscible silicate and carbonate melts separated from the afrikandite body, although the carbonate melt was not separated completely from the silicate melt fraction. In general, during the evolution of the carbonate melt at Kerimasi, concentrations of P2O5 and SiO2 decreased, whereas volatile content (alkalis, S, F, Cl and H2O) increased. Volatiles were incorporated principally in nyerereite, shortite, burbankite, nahcolite and sulfohalite as identified by Raman spectrometry. These extremely unstable minerals cannot be found in the bulk rock, because of alteration by secondary processes. On the basis of these data, an evolutionary model is developed for Kerimasi plutonic rocks. |
DS201505-0240 2015 | Kalnins, L.M., Simons, F.J., Kirby, J.F., Wang, D.V., Olhede, S.C. | On the robustness of estimates of mechanical anisotropy in the continental lithosphere: a North American case study and global reanalysis. | Earth and Planetary Science Letters, Vol. 419, pp. 43-51. | United States, Canada | Tectonics |
DS201509-0405 2015 | Kamenetsky, V.S., Mitchell, R.H., Maas, R., Giuliani, A., Gaboury, D., Zhitova, L. | Chlorine in mantle derived carbonatite melts revealed by halite in the St. Honore intrusion ( Quebec, Canada). | Geology, Vol. 43, 8, pp. 687-690. | Canada, Quebec | Carbonatite |
| Abstract: Mantle-derived carbonatites are igneous rocks dominated by carbonate minerals. Intrusive carbonatites typically contain calcite and, less commonly, dolomite and siderite as the only carbonate minerals. In contrast, lavas erupted by the only active carbonatite volcano on Earth, Oldoinyo Lengai, Tanzania, are enriched in Na-rich carbonate phenocrysts (nyerereite and gregoryite) and Na-K halides in the groundmass. The apparent paradox between the compositions of intrusive and extrusive carbonatites has not been satisfactorily resolved. This study records the fortuitous preservation of halite in the intrusive dolomitic carbonatite of the St.-Honoré carbonatite complex (Québec, Canada), more than 490 m below the present surface. Halite occurs intergrown with, and included in, magmatic minerals typical of intrusive carbonatites; i.e., dolomite, calcite, apatite, rare earth element fluorocarbonates, pyrochlore, fluorite, and phlogopite. Halite is also a major daughter phase of melt inclusions hosted in early magmatic minerals, apatite and pyrochlore. The carbon isotope composition of dolomite (?13C = –5.2‰) and Sr-Nd isotope compositions of individual minerals (87Sr/86Sri = 0.70287 in apatite, to 0.70443 in halite; ?Nd = +3.2 to +4.0) indicate a mantle origin for the St.-Honoré carbonatite parental melt. More radiogenic Sr compositions of dolomite and dolomite-hosted halite and heavy oxygen isotope composition of dolomite (?18O = +23‰) suggest their formation at some time after magma emplacement by recrystallization of original magmatic components in the presence of ambient fluids. Our observations indicate that water-soluble chloride minerals, common in the modern natrocarbonatite lavas, can be significant but ephemeral components of intrusive carbonatite complexes. We therefore infer that the parental magmas that produce primary carbonatite melts might be enriched in Na and Cl. This conclusion affects existing models for mantle source compositions, melting scenarios, temperature, rheological properties, and crystallization path of carbonatite melts. |
DS201506-0279 2015 | Kamenetsky, V.S., Yaxley, G.M. | Carbonate-silicate iquid immiscibility in the mantle propels kimberlite magma ascent. | Geochimica et Cosmochimica Acta, Vol. 158, pp. 48-56. | Mantle | Carbonatite, content of kimberlite melts |
DS201510-1776 2015 | Kamenetsky, V.S.,Park, J-W., Mungall, J.E., Pushkarev, E.V., Ivanov, A.V., Kamenetsky, M.B., Yaxley, G.M. | Crystallization of platinum group minerals from silicate melts: evidence from Cr-spinel hosted inclusions in volcanic rocks. | Geology, Vol. 43, 10, pp. 903-906. | Russia | Meimechite |
| Abstract: The formation of platinum-group minerals (PGM) during magma differentiation has been suggested to be an important process in primitive magma evolution, but decisive textural evidence is difficult to obtain because PGM tend to be very small and very rare. We have investigated Cr-spinel phenocrysts from two oxidized magmas (Siberian meimechite and Vanuatu [Ambae Island] arc picrite) and one reduced magma (Uralian [Russia] ankaramite) for PGM inclusions and their platinum-group element (PGE) contents. We observed Os-Ir and Pt-Fe alloys entrapped as inclusions in Cr-spinel in all three suites of lava. The alloys may occur in association with PGE-bearing sulfides and co-trapped silicate melt. Cr-spinel crystals also contain measurable amounts of Os, Ir, Ru, and Rh, which are at concentrations 2×–100× higher than mantle values. Thermodynamic models indicate that the arc picrite and ankaramite melts were probably both saturated with the observed PGM phases, whereas the Os-Ir alloy grain observed in the meimechite is not in equilibrium with the “bulk” melt. Our results demonstrate that PGM (alloys and sulfides) occur as liquidus phases in primitive (unfractionated) melts at high temperature and at a variety of redox conditions, and that Cr-spinel is a significant host of PGE, either in the crystal structure or as PGM inclusions. |
DS201511-1851 2015 | 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/s00710-015-0401-7 | South America, Brazil, Mato Grosso | Juina 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. |
DS201504-0204 2015 | Kaminsky, F.V., Ryabchikov, I.D., McCammon, C.A., Longo, M., Abakumov, A.M., Turner, S., Heidari, H. | Oxidation potential in the Earth's lower mantle as recorded by ferropericlase inclusions in diamond. | Earth and Planetary Science Letters, Vol. 417, pp. 49-56. | South America, Brazil | Deposit - Juina |
DS201504-0205 2015 | Kaminsky, F.V., Ryabchikov, I.D., Wirth, R. | A primary natrocarbonatite association in the deep Earth. | Mineralogy and Petrology, in press available 12p. | South America, Brazil | Deposit - Inclusions in Juina |
DC201504-1504 2015 | Karelian Diamond Resources plc. | Discovery of potential new diamond source… kimberlite in Kuhmo area of eastern Finland. | Karelian Diamond Resources, Mar. 20, 1p. | Europe, Finland | News item - press release |
DC201507-1505 2015 | Karelian Diamond Resources plc. | Kimberlite intersected in five further pits in Kuhmo. | Karelian Diamond Resources, June 10, 1p. | Europe, Finland | News item - press release |
DC201508-1506 2015 | Karelian Diamond Resources plc. | Karelian Diamonds gets "excellent" chemistry results at Riihivaara. Kuhmo region. | Karelian Diamond Resources Plc., July 1, 2p. | Europe, Finland | News item - press release |
DS201509-0407 2014 | Karfunkel, J., Hoover, D., Fernandes, A.F., Sgarbi, G.M.C., Kambrock, K., Oliviera, G.D. | Diamonds from the Coromandel area, west Minas Gerais State, Brazil: an update and new dat a on surface sources and origin. | Brazil Journal of Geology, Vol. 44, 2, pp. 325-338. | South America, Brazil, Minas Gerais | Deposit - Coromandel |
| Abstract: Important diamond deposits southeast of Coromandel and the local geology have been studied in an attempt to understand what surface source provided the stones. River gravels of Pleistocene to Recent age from this region have supplied most of Brazil’s large diamonds over 100 ct. The upper cretaceous Capacete Formation of the Mata da Corda Group, composed of mafic volcanoclastic, pyroclastic and epiclastic material, has been worked locally for diamonds, nevertheless considered non-economic. The authors present results of their study of a deactivated small mine, representing the first report with description and analyses of two gem diamonds washed from this material. Hundreds of kimberlites, discovered in the last half century in the region, are sterile or non-economic. We propose that the surface source of the diamonds is the Capacete “conglomerado”. The volume of this material is enormous representing a potential resource for large-scale mining. The authors suggest detailed studies of the volcanic facies of this unit focusing on the genesis, distribution and diamond content. As to the question concerning the origin of these diamondiferous pyroclastic rocks, the authors exclude the kimberlites and point towards the large Serra Negra and Salitre alkaline complexes which are considered the primary source for the pyroclastic units of the Mata da Corda Group. They propose that early eruptive phases of this alkaline complex brought diamonds from a mantle source to the surface, much as happens with traditional kimberlites, to explain the association of such huge carbonatite complexes and diamonds. |
DS201509-0408 2015 | Karfunkel, J., Hoover, D., Fernandes, A.F., Sgarbi, G.M.C., Oliviera, G.D., Walde, D., Michelfelder, G. | Surface source of Coromandel diamonds ( Minas Gerais State) Brazil and their possible origin from the Serra Negra/Salitre Supervolcano. | Neues Jahrbuch fur Geologie und Palaontologie , Vol. 277, 2, pp. 237-250. | South America, Brazil, Minas Gerais | Deposit - Coromandel |
| Abstract: The origin of diamonds in the Coromandel area has been an enigma for many years, in spite of high investment in conventional and high tech prospecting methods by major mining companies for over half a century. The authors review the history, and then discuss the two principal hypotheses to explain the source of these alluvial diamonds. After mapping the headwater region of one of the richest alluvial diamond rivers, the Santo Antônio do Bonito River, they reject both principal hypotheses and conclude that the surficial source can be only the Upper Cretaceous Capacete Formation, composed of pyroclastics and epiclastics. Based on geophysical data from the literature, combined with field observations the authors suggest that the largest alkaline complex, situated within the diamond producing area, the Serra Negra/Salitre Complex has been the primary source for those pyroclastics of the Capacete Formation and the diamonds. The plugs of this complex are 15-30 times deeper than average kimberlites and other alkaline complexes in the region, and its excess of volume of the intrusive is three orders of magnitude larger than a typical kimberlite. With an intrusive volume of over 1000 km3 the complex is suggested to be a possible supervolcano. This explains the vast areal distribution of the pyroclastics and diamonds. This new hypothesis has advantages and disadvantages, some of them discussed in the paper and leading to the conclusion that further research is needed. |
DS201502-0067 2015 | Kargin, A., Sazonova, L., Nosova, A., Kovalchuk, E., Minevrina, E. | Metasomatic processes in the mantle beneath the Arkangelsk province, Russia: evidence from garnet in mantle peridotite xenoliths, Grib pipe. | Economic Geology Research Institute 2015, Vol. 17,, # 748, 1p. Abstract | Russia, Kola Peninsula, Archangel | Deposit - Grib |
DS201505-0243 2015 | Katzir, Y., Anenburg, M., Kaminchik, J., Segev, A., Blichert-Toft, J., Spicuzza, M.J., Valley, J.W. | Garnet pyroxenites as markers of recurring extension and magmatism at the rifted margins of the Levant basin. | Israel Geological Society, Abstracts 1p. | Europe, Israel, Mt. Carmel | Pyroxenite |
DS201509-0409 2015 | Kaur, G., Mitchell, R.H. | Mineralogy of the P-12 K-Ti-richterite diopside olivine lamproite from Wajrakarur, Andhra Pradesh, India: implications for subduction related magmatism in eastern India. | Mineralogy and Petrology, In press available 23p. | India, Andhra Pradesh | Deposit - P-12 |
| Abstract: The P-12 "para-kimberlite" from Wajrakarur consists of forsteritic olivine, Al-Na-poor diopside, Fe-Ti-rich, Al-poor phlogopite, K-Ti-richterite, spinel, perovskite, cymrite, apatite, barite, Ba-Sr- bearing calcite, gittinsite, witherite, strontianite, and hydrogrossular (hydrogarnet). The rock also contains small clasts consisting dominantly of calcite, with lesser Ba-Sr-bearing calcite, cymrite, barite, strontianite, witherite, apatite, and hydrogrossular. Two generations of forsteritic olivine (Fo80-93) crystals are present: common phenocrystal-to-microphenocrystal; and rare anhedral macrocrystic olivines. Phlogopite occurs as microphenocrysts and as groundmass poikilitic plates with inclusions of spinel, perovskite, apatite, and chlorite pseudomorphs (after pyroxene). Phlogopites also occur as reaction rims around olivine crystals. The phlogopites have extremely low Al2O3 (2.2-3.8 wt.%), moderate-to-high FeO (6.9-16 wt.%), TiO2(1.9-4.6 wt.%), and Na2O (0.4-2.7 wt.%) contents and are enriched in fluorine (up to 6.0 wt.%) and considered to be tetraferriphlogopite. The pyroxenes occur in five parageneses as: (1) phenocrysts and microphenocrysts; (2) small slender crystals(<30 µm) forming part of the groundmass; (3) the cores of richterite crystals; (4) reaction products replacing earlier-formed olivine; (5) acicular crystals mantling carbonate clasts. These pyroxenes do not differ significantly in composition and are all diopsides with minor variation in their TiO2, Al2O3, Na2O contents. Titanian-potassium richterite commonly occurs as: (1) groundmass poikilitic plates; (2) small prismatic crystals (<30 µm); (3) reaction rims on olivine and pyroxene crystals. Groundmass poikilitic richterites commonly enclose pyroxene and apatite. Perovskites have a bimodal size distribution. Small (<20 µm) euhedral perovskites are scattered throughout the groundmass, whereas larger (100-300 µm) subhedral-to-euhedral perovskites are patchily-zoned and commonly broken. Micro-clasts consisting of accumulations of perovskite with phlogopite and apatite are also present. Spinels occur as large atoll crystals and small (<20 µm), euhedral-to-subhedral crystals, scattered throughout the groundmass. Some small spinel crystals are also present in the rims of olivine and pyroxene crystals. Atoll spinels are up to 100 µm in size, commonly with single and double cores. Atoll spinels are typically associated with perovskites. The euhedral-to-subhedral small spinels are ulvospinels. The atoll spinels have cores of titanian aluminous magnesiochromite with rims of magnesian titaniferous magnetite. The spinels have compositions which evolve along the lamproite-spinel compositional trend. Zoned calcite crystals occur as residual phases. Late stage residual calcite and carbonate clasts host prismatic cymrite crystals which are interpreted as pseudomorphs after potassium feldspar and/or barite. Subhedral-to-euhedral gittinsite and its Sr-analog are reported for the first time from the groundmass carbonate-chlorite mesostasis of a lamproite. Square-to-rectangular crystals of cymrite and hydrogrossular occur in the carbonate clasts and groundmass material. Barite anhedra commonly occur in the carbonate clasts together with witherite, strontianite, and Ba-Sr-bearing calcite. The texture and compositions of olivine, phlogopite, spinel, and K-Ti-richterite, together with the presence of cymrite pseudomorphs, possibly after potassium feldspar, demonstrate that this intrusion is a bona fide olivine lamproite and not a kimberlite. It is postulated that this, and other lamproites, located adjacent to the Eastern Ghats Mobile Belt, are derived by extensional decompressional melting of ancient subduction zones underlying the cratonic regions. |
DC201501-1507 2014 | Kennady Diamonds Inc. | Kennady Diamonds intersects kimberlite at Kelvin. | Kennady Diamonds Inc., Dec. 16, 1p. | Canada, Northwest Territories | News item - press release |
DC201502-1508 2014 | Kennady Diamonds Inc. | Kennady Diamonds announces Kelvin mini-bulk sample grade of 2.59 carats per tonne. | Kennady Diamonds Inc., Dec. 24, 1p. | Canada, Northwest Territories | News item - press release |
DC201503-1509 2015 | Kennady Diamonds Inc. | Kennady Diamonds announces Kelvin exploration results. | Kennady Diamonds Inc., Jan. 26, 2p. | Canada, Northwest Territories | News item - press release |
DC201503-1510 2015 | Kennady Diamonds Inc. | Kennady Diamonds intercepts kimberlite at Kelvin. | Kennady Diamonds Inc., Feb. 2, 1p. | Canada, Northwest Territories | News item - press release |
DC201503-1511 2015 | Kennady Diamonds Inc. | Kennady Diamonds intercepts 54.5 meters of kimberlite at Kelvin. | Kennady Diamonds Inc., Feb. 12, 2p. | Canada, Northwest Territories | News item - press release |
DC201503-1512 2015 | Kennady Diamonds Inc. | Dermot Desmond backed diamond explorer a mine ' within five years'. Kelvin | Kennady Diamonds Inc., Feb. 10, 1/4p. | Canada, Northwest Territories | News item - press release |
DC201503-1513 2015 | Kennady Diamonds Inc. | Kennady Diamonds closes first tranche of C$20 million non-brokered private placement. | Kennady Diamonds Inc., Feb. 19, 1p. | Canada, Northwest Territories | News item - press release |
DC201504-1514 2015 | Kennady Diamonds Inc. | Kennady Diamonds intersects 80 meters of kimberlite at Kelvin. | Kennady Diamonds Inc., Feb. 24, 3p. | Canada, Northwest Territories | News item - press release |
DC201504-1515 2015 | Kennady Diamonds Inc. | Kennady Diamonds closes second tranche of $ C 20 million non-brokered private placement. | Kennady Diamonds Inc., Feb. 25, 1p. | Canada, Northwest Territories | News item - press release |
DC201504-1516 2015 | Kennady Diamonds Inc. | Kennady Diamond closes final tranche of non-brokered private placement. | Kennady Diamonds Inc., Mar. 10, 1p. | Canada, Northwest Territories | News item - press release |
DC201504-1517 2015 | Kennady Diamonds Inc. | Kennady Diamonds intersects kimberlite at Faraday. | Kennady Diamonds Inc., Mar. 18, 2p. | Canada, Northwest Territories | News item - press release |
DC201504-1518 2015 | Kennady Diamonds Inc. | Kennady Diamonds intersects 37 meters of kimberlite at Faraday. | Kennady Diamonds Inc., Mar. 24, 2p. | Canada, Northwest Territories | News item - press release |
DC201505-1519 2015 | Kennady Diamonds Inc. | Kennady Diamonds extends strike of Faraday and intersects 52 meters of kimberlite. | Kennady Diamonds Inc., Mar. 30, 4p. | Canada, Northwest Territories | News item - press release |
DC201505-1520 2015 | Kennady Diamonds Inc. | Kennady Diamonds recovers 436 tonne Kelvin bulk sample: intersects 76 meters of kimberlite at Faraday. | Kennady Diamonds Inc., Apr. 9, 2p. | Canada, Northwest Territories | News item - press release |
DC201505-1521 2015 | Kennady Diamonds Inc. | Kennady Diamonds updates Kennady North drill program. | Kennady Diamonds Inc., Apr. 20, 3p. | Canada, Northwest Territories | News item - press release |
DC201505-1522 2015 | Kennady Diamonds Inc. | Kennady Diamonds announces Kelvin diamonds recovery results. | Kennady Diamonds Inc., Apr. 23, 2p. | Canada, Northwest Territories | News item - press release |
DC201506-1523 2015 | Kennady Diamonds Inc. | Kennady Diamonds updates Kennady North drill program. | Kennady Diamonds Inc., May 1, 1p. | Canada, Northwest Territories | News item - press release |
DC201506-1524 2015 | Kennady Diamonds Inc. | Kennady Diamonds intersects 73 meters of kimberlite at Faraday 2. Kennday North | Kennady Diamonds Inc., May 19, 3p. | Canada, Northwest Territories | News item - press release |
DC201506-1525 2015 | Kennady Diamonds Inc. | Kennady Diamonds drills 194 meters of kimberlite at Kelvin. | Kennady Diamonds Inc., May 27, 2p. | Canada, Northwest Territories | News item - press release |
DC201507-1526 2015 | Kennady Diamonds Inc. | Kennady Diamonds drills 178 meters of kimberlite at Kelvin.. North lobe. | Kennady Diamonds Inc., June 4, 3p. | Canada, Northwest Territories | News item - press release |
DC201507-1527 2015 | Kennady Diamonds Inc. | Kennady Diamonds drills 159 meters of kimberlite at Kelvin. | Kennady Diamonds Inc., June 11, 2p. | Canada, Northwest Territories | News item - press release |
DC201507-1528 2015 | Kennady Diamonds Inc. | Kennady Diamonds drills 46 meters of kimberlite at Faraday 2. | Kennady Diamonds Inc., June 16, 2p. | Canada, Northwest Territories | News item - press release |
DC201507-1529 2015 | Kennady Diamonds Inc. | Kennady Diamonds drills 156 meters of kimberlite at Kelvin and 51 meters of kimberlite at Faraday 2. | Kennady Diamonds Inc., June 25, 3p. | Canada, Northwest Territories | News item - press release |
DC201508-1530 2015 | Kennady Diamonds Inc. | Kennady Diamonds updates Kennady North drill program. | Kennady Diamonds Inc., July 13, 2p. | Canada, Northwest Territories | News item - press release |
DC201508-1531 2015 | Kennady Diamonds Inc. | Kennady Diamonds announces Faraday 2 diamond recovery results. | Kennady Diamonds Inc., July 15, 3p. | Canada, Northwest Territories | News item - press release |
DC201508-1532 2015 | Kennady Diamonds Inc. | Kennady Diamonds finds Faraday 2 diamond during core logging. | Kennady Diamonds Inc., July 16, 1p. | Canada, Northwest Territories | News item - press release |
DC201508-1533 2015 | Kennady Diamonds Inc. | Kennady Diamonds drills 92 meters of kimberlite at Kelvin. | Kennady Diamonds Inc., July 23, 1p. | Canada, Northwest Territories | News item - press release |
DC201509-1534 2015 | Kennady Diamonds Inc. | Kennady Diamonds announces C$4 M non-brokered private placement. Kelvin | Kennady Diamonds Inc., July 29, 1p. | Canada, Northwest Territories | News item - press release |
DC201509-1535 2015 | Kennady Diamonds Inc. | Kennady Diamonds closes C$4 million non-brokered private placement. Kelvin | Kennady Diamonds Inc., Aug. 12, 1p. | Canada, Northwest Territories | News item - press release |
DC201509-1536 2015 | Kennady Diamonds Inc. | Provides Kennady North project update and exploration of the MZ kimberlite. | Kennady Diamonds Inc., Aug. 17, 2p. | Canada, Northwest Territories | News item - press release |
DC201509-1537 2015 | Kennady Diamonds Inc. | Kennady Diamonds annnounces Kelvin bulk sample diamond recovery results. | Kennady Diamonds Inc., Aug. 26, 3p. | Canada, Northwest Territories | News item - press release |
DC201510-2349 2015 | Kennady Diamonds Inc. | Kennady Diamonds updates Kennady North drilling. | Kennady Diamonds Inc., Aug. 31, 3p. | Canada, Northwest Territories | News item - press release |
DC201510-2350 2015 | Kennady Diamonds Inc. | Kennady Diamonds announces C$48 million private placement. | Kennady Diamonds Inc., Sept. 16, 1p. | Canada, Northwest Territories | News item - press release |
DC201510-2351 2015 | Kennady Diamonds Inc. | Kennady Diamonds updates Kennady North drilling. Kelvin | Kennady Diamonds Inc., Sept. 21, 2p. | Canada, Northwest Territories | News item - press release |
DC201511-2386 2015 | Kennady Diamonds Inc. | Kennady Diamonds closes first tranche of C$48 million non-brokered private placement ( Kelvin, Faraday, MZ and Doyle) | Kennady Diamonds Inc., Oct. 1, 2p. | Canada, Northwest Territories | News item - press release |
DC201511-2387 2015 | Kennady Diamonds Inc. | Kennady Diamonds announces Kelvin North sample grade of 2.6 carats per tonne. | Kennady Diamonds Inc., Oct. 5, 3p. | Canada, Northwest Territories | News item - press release |
DC201511-2388 2015 | Kennady Diamonds Inc. | Kennady Diamonds closes final tranche of $ 48 million non-brokered private placement North project. | Kennady Diamonds Inc., Oct. 8, 1p. | Canada, Northwest Territories | News item - press release |
DC201511-2389 2015 | Kennady Diamonds Inc. | Mr. Dermot Desmond announces further investment in Kennady Diamonds Inc. ( 23.6%) | Kennady Diamonds Inc., Oct. 9, 1p. | Canada, Northwest Territories | News item - press release |
DC201512-2435 2015 | Kennady Diamonds Inc. | Kennady Diamonds updates Kennady North drilling. | Kennady Diamonds Inc., Oct. 28, 3p. | Canada, Northwest Territories | News item - press release |
DC201512-2436 2015 | Kennady Diamonds Inc. | Kennady Diamonds announces Kelvin North sample grade of 2.53 carats per tonne. | Kennady Diamonds Inc., Nov. 19, 4p. | Canada, Northwest Territories | News item - press release |
DS201511-1852 2015 | Kennett, B.L.N. | Lithosphere-asthenosphere P wave reflectivity across Australia. | Earth and Planetary Science Letters, Vol. 431, pp. 225-235. | Australia | Geophysics - seismics - cratons |
| Abstract: A direct image of P-wave reflectivity in the lithosphere and asthenosphere beneath seismic stations is extracted from stacked autocorrelograms of continuous component records. The autocorrelograms emphasise near vertically travelling waves, so that multiples are more muted than in receiver function studies and it is possible to work at higher frequencies than for receiver functions. Across a wide range of geological environments in Australia, in the 0.5-4.0 Hz frequency band, distinct reflections are seen in the crust underlain by weaker reflectivity in the lithosphere and asthenosphere. The base of crustal reflectivity fits well with Moho estimates from other classes of information. Few mantle reflectors have been seen in conventional reflection profiling at frequencies above 10 Hz; the presence of reflections in the 0.5-4.0 Hz band suggests variations on vertical scales of a few hundred metres with amplitudes of the order of 1%. There are slight indications of a change of reflection character in the lower part of the lithosphere in the transition to the asthenosphere. At a few stations there is a very clear lamination at asthenospheric depth, as well as reflections from the base of the S wave low velocity zone. Reflection bands often occur at depths where discontinuities have been inferred from S wave receiver function work at the same station, but would not by themselves be distinctive of a mid-lithosphere discontinuity. |
DS201506-0281 2015 | Kent, D.V., Kjarsgaard, B.A., Gee, J.S., Muttoni, G., Heaman, L.M. | Tracking the Late Jurassic apparent ( or true) polar shift in U-Pb-dated kimberlites from cratonic North America ( Superior Province of Canada). | Geochemistry, Geophysics, Geosystems: G3, Vol. 16, 4, pp. 983-994. | Canada, Ontario, Timiskaming | Deposit - Peddie |
DS201502-0068 2015 | Khokhryakov, A.F., Nechaev, D.V. | Typomorphic featues of graphite inclusions in diamond: experimental data. | Russian Geology and Geophysics, Vol. 56, 1-2, pp. 232-238. | Technology | Diamond inclusions |
DS201508-0361 2015 | Khokhryakov, A.F., Palyanov, Y.N. | Effect of crystal defects on diamond morphology during dissolution in the mantle. | American Mineralogist, Vol. 100, pp. 1528-1532. | Technology | Diamond morphology |
DM201503-0849 2015 | Kilalea, D | Dominion Diamond Corp Jay - a medium term jewel for DDC. | RBC Capital Markets, Jan. 27, 7p. | Canada, Northwest Territories | News item - Dominion |
DM201503-0850 2015 | Kilalea, D | Petra Diamonds Ltd. H1 IMS: near term pain ahead of grade delivery; but dividends starting. | RBC Capital Markets, Jan. 26, 11p. | Africa, South Africa | News item - Petra |
DM201503-0851 2015 | Kilalea, D | Gem Diamonds Limited .. Tough rough conditions weigh…Letseng and Ghaghoo | RBC Capital Markets, Jan. 28, 11p. | Africa, Botswana, Lesotho | News item - Gem Diamonds |
DM201503-0852 2015 | Kilalea, D | Alrosa Ao Political backdrop and currency weigh. | RBC Capital Markets, Jan. 29, 11p. | Russia | News item - Alrosa |
DC201509-1541 2015 | Kilalea, D. | Anglo American plc. Dark side of the moon. Challenges. | RBC Capital Markets, Aug. 4, 16p. | Global | News item - Anglo |
DM201501-0853 2014 | Kilalea, D. | RBC Diamond Digest: push and pull between diamantaires and miners on prices to continue in 2015. | RBC Capital Markets, Dec. 9, 38p. | Global | News item - review rough prices |
DM201501-0854 2014 | Kilalea, D. | Dominion Diamond Corporation.. Positive Q3 with balance sheet and dividend focus. | RBC Capital Markets, Dec. 12, 7p. | Canada, Northwest Territories | News item - Dominion |
DM201502-0855 2014 | Kilalea, D. | Stornoway Diamond Corp. NAV discount offers attractive entry point. Positive | RBC Capital Markets, Dec. 18, 7p. | Canada, Quebec | News item - Stornoway |
DM201502-0856 2014 | Kilalea, D. | Lucara looks to divest Mothae to focus on better opportunities. Positive | RBC Capital Markets, Dec. 18, 1/4p. | Africa, Lesotho | News item - Lucara |
DM201502-0857 2015 | Kilalea, D. | Firestone Diamonds plc. Initiating coverage: a new diamond mine in Lesotho. | RBC Capital Markets, Jan. 21, 20p. | Africa, Lesotho | News item - Firestone |
DM201502-0858 2015 | Kilalea, D. | Petra Diamonds Ltd. H1 IMS: near term pain ahead of grade delivery but dividends starting. | RBC Capital Markets, Jan. 26, 9p. | Africa, South Africa | News item - Petra |
DM201502-0859 2015 | Kilalea, D. | RBC Diamond digest .. A difficult market for 2015, De Beers stepping up to the plate, bank debt still a concern, currency issues. | RBC Capital Markets, Jan. 26, 18p. | Global | News item - overview for 2015 |
DM201504-2467 2015 | Kilalea, D. | The start of a new funding formula…. | RBC Capital Markets , Mar. 5, 6p. | Global | News item - prices, banks |
DM201504-2468 2015 | Kilalea, D. | Rerating driven by improving quality of diamond miners, not rising rough prices. | RBC Capital Markets , Mar. 25, 16p. | Global | News item - overview of diamond companies |
DM201504-2479 2015 | Kilalea, D. | RBC diamond conference feedback. .. Strong sector… marketing concerns | RBC Capital Markets , Mar. 6, 10p. | Global | News item - robust sector |
DM201505-0860 2015 | Kilalea, D. | De Beers finds conditions tough in March. | RBC Capital Markets, Mar. 31, 2p. | Global | News item - De Beers |
DM201505-0861 2015 | Kilalea, D. | Dominion Diamond Corp. Q4 EPS misses on FX, otherwise robust. | RBC Capital Markets, Apr. 9, 7p. | Canada, Northwest Territories | News item - Dominion |
DM201505-0862 2015 | Kilalea, D. | ABN AMRO exits Indian loan book to a local bank. | RBC Capital Markets, Apr. 10, 1/4p. | India | News item - ABN Amro |
DM201505-0863 2015 | Kilalea, D. | Large stones pick up again with a 342 ct high colour gem recovered at Karowe. | RBC Capital Markets, Apr. 21, 1p. | Africa, Botswana | News item - Lucara |
DM201505-0864 2015 | Kilalea, D. | Petra Diamonds Ltd. Balance sheet strengthened and value adding new Culli nan plant. | RBC Capital Markets, Apr. 24, 12p. | Africa, South Africa | News item - Petra |
DM201505-0865 2015 | Kilalea, D. | Lucara Diamonds - large stones pick up again with 342 ct high colour gem recovered at Karowe. | RBC Capital Markets, Apr. 24, 1/2p. | Africa, Botswana | News item - Lucara |
DM201506-0866 2015 | Kilalea, D. | Stornoway broadening the equity register. | RBC Capital Markets, May 1, 1/2p. | Canada, Quebec | News item - Stornoway |
DM201506-0867 2015 | Kilalea, D. | Lucara Diamond Corporation enters into agreement with Paragon Diamonds for the sale of Mothae. | RBC Capital Markets, May 5, 1p. | Africa, Lesotho | News item - Lucara |
DM201506-0868 2015 | Kilalea, D. | Lucara Diamond Corp. Q1 weaker than RBC driven by top line; guidance unchanged. Karowe | RBC Capital Markets, May, 13, 8p. | Africa, Botswana | News item - Lucara |
DM201506-0869 2015 | Kilalea, D. | Petra Diamonds Ltd. Putting focus on the new plant. Cullinan | RBC Capital Markets, May 15, 8p. | Africa, South Africa | News item - Petra |
DM201506-0870 2015 | Kilalea, D. | Polished picks up but rough lags as summer begins. | RBC Capital Markets, May 27, 18p. | Global | News item - markets |
DM201507-0871 2015 | Kilalea, D. | Dominion Diamond Corp. Q1 Preview - a tough quarter with pressure on margins. | RBC Capital Markets, June 3, 6p. | Canada, Northwest Territories | News item - press release |
DM201507-0872 2015 | Kilalea, D. | Firestone Diamonds plc. Delays and some capex creep at Liqhobong. | RBC Capital Markets, June 23, 4p. | Africa, Lesotho | News item - Firestone |
DM201508-0873 2015 | Kilalea, D. | RBC Diamond Digest.. Through the glass darkly. | RBC Capital Markets, July , 17p. | Global | News item - markets |
DM201508-0874 2015 | Kilalea, D. | Alrosa Ao Q2 production a little weaker than forecast. | RBC Capital Markets, July 21, 7p. | Russia | News item - Alrosa |
DM201508-0875 2015 | Kilalea, D. | Diamond digest: Buyers rebel against high rough prices. DTC | RBC Capital Markets, July 22, 4p. | Global | News item - De Beers |
DM201508-0876 2015 | Kilalea, D. | Petra Diamonds : Q4 production and new guidance. | RBC Capital Markets, July 27, 10p. | Africa, South Africa | News item - Petra |
DM201509-0877 2015 | Kilalea, D. | Lucara Diamond Corporation.Good Q2 revenue drives a beat in H1. Karowe | RBC Capital Markets, Aug. 12, 4p. | Africa, Botswana | News item - Lucara |
DM201509-0878 2015 | Kilalea, D. | Lucara Diamond Corporation. Lower sales guidance impacts on rating. Karowe | RBC Capital Markets, Aug. 13, 7p. | Africa, Botswana | News item - Lucara |
DM201509-0879 2015 | Kilalea, D. | Lucara Diamond Corp. Another bounty of sparkling nuggets. Karowe | RBC Capital Markets, Aug. 18, 4p. | Africa, Botswana | News item - Lucara |
DM201509-0880 2015 | Kilalea, D. | Gem Diamonds Limited H1 results a beat driven by costs. Letseng Ghaghoo | RBC Capital Markets, Aug. 19, 2p. | Africa, Lesotho, Botswana | News item - Gem Diamonds |
DM201509-0881 2015 | Kilalea, D. | Stornoway Diamond Corp. On track and getting closer to production. Renard | RBC Capital Markets, Aug. 19, 11p. | Canada, Quebec | News item - Stornoway |
DM201509-0882 2015 | Kilalea, D. | Gem Diamonds Limited Waiting on Ghaghoo. | RBC Capital Markets, Aug. 20, 5p. | Africa, Botswana | News item - Gem Diamonds |
DM201509-0883 2015 | Kilalea, D. | Dominion Diamond Corporation. Ekati plant changes start delivering. Our view: a good quarter from an efficiency perspective, we expect more to come. | RBC Capital Markets, Aug. 21, 5p. | Canada, Northwest Territories | News item - Dominion |
DM201509-0884 2015 | Kilalea, D. | Anglo American plc. De Beers reported to have lowered prices 7-10%. | RBC Capital Markets, Aug. 24, 4p. | Global | News item - De Beers |
DM201509-0885 2015 | Kilalea, D. | Kimberley dat a show price weakness for 2014; this year should fall more. | RBC Capital Markets, Aug. 25, 5p. | Global | News item - prices |
DM201510-2048 2015 | Kilalea, D. | The investment case fades for a while. | RBC Capital Markets, Diamond Digest, Sept. 7, 18p. | Global | News item - prices, supply, demand |
DM201510-2049 2015 | Kilalea, D. | Dominion Diamond Corp. Q2 a miss driven by one off factors; inventory builds. | RBC Capital Markets, Sept. 11, 4p. | Canada, Northwest Territories | News item - Dominion |
DM201510-2050 2015 | Kilalea, D. | Dominion Diamond Corp. Q2 a miss driven by one off factors; inventory builds. Adjusting model. | RBC Capital Markets, Sept. 14, 5p. | Canada, Northwest Territories | News item - Dominion |
DM201510-2051 2015 | Kilalea, D. | Gem fetches $ 19 m for 357ct white stone in Antwerp. | RBC Capital Markets, Sept. 14, 1p. | Africa, Lesotho | News item - Gem Diamonds |
DM201510-2052 2015 | Kilalea, D. | Petra Diamonds Ltd. Rough pricing is the key to near-term risk. | RBC Capital Markets, Sept. 18, 4p. | Africa, South Africa | News item - Petra |
DM201510-2053 2015 | Kilalea, D. | Global diamond jewellery growth projected at 3 % in USD terms by De Beers - but less rough forecast to be sold. | RBC Capital Markets, Sept. 21, 1p. | Global | News item - jewellery |
DM201510-2054 2015 | Kilalea, D. | Firestone's frst drawdown of Liqhobong debt - project on track for first production Q4 2016. | RBC Capital Markets, Sept. 24, 1/4p. | Africa, Lesotho | News item - Firestone |
DM201511-2145 2015 | Kilalea, D. | Renard ahead of schedule as second tranche of stream received. | RBC Capital Markets, Oct.. 1, 1p. | Canada, Quebec | News item - Stornoway |
DM201511-2146 2015 | Kilalea, D. | Mountain Province Diamonds Inc. suffering from lack of interest. Gahcho Kue | RBC Capital Markets, Oct. 1, 13p. | Canada, Northwest Territories | News item - Mountain Province Diamonds |
DM201511-2147 2015 | Kilalea, D. | De Beers struggles in October Sight. | RBC Capital Markets, Oct. 12, 4p. | Global | News item - De Beers |
DM201511-2148 2015 | Kilalea, D. | Lucara site visit to Karowe. | RBC Capital Markets, Oct. 8, 4p. | Africa, Botswana | News item - Lucara |
DM201511-2149 2015 | Kilalea, D. | Lucara site visit highlights plant advances. Karowe. | RBC Capital Markets, Oct. 14, 18p. | Africa, Botswana | News item - Lucara |
DM201512-2254 2015 | Kilalea, D. | Lucara Diamond Corp. a credible result in a tough market. | RBC Capital Markets, Nov. 6, 9p. | Africa, Botswana | News item - Lucara |
DM201512-2255 2015 | Kilalea, D. | Cloudy outlook should persist well into 2016. Overview of companies | RBC Capital Markets, Nov. 10, 14p. | Global | News item - markets |
DM201512-2256 2015 | Kilalea, D. | Gem Diamonds Limited … Large stone sweetens Letseng revenue in softer market. ( 357 carat stone sold for $ 19.3 m. | RBC Capital Markets, Nov. 11, 5p. | Africa, Lesotho | News item - Gem Diamonds |
DM201512-2257 2015 | Kilalea, D. | Petra Diamonds Ltd. Shining the spotlight on the balance sheet. | RBC Capital Markets, Nov. 11, 18p. | Africa, South Africa | News item - Petra |
DM201512-2258 2015 | Kilalea, D. | Petra's in the pink - 23 ct pink diamond recovered at Williamson. | RBC Capital Markets, Nov. 27, 1p. | Africa, Tanzania | News item - Petra |
DC201504-1544 2015 | Kimberley Diamonds Ltd. | Directors' report: Ellendale, Lerala | Kimberley Diamonds Ltd., Mar. 6, 2p. | Australia, Africa, Botswana | News item - press release |
DC201505-1545 2015 | Kimberley Diamonds Ltd. | Ellendale diamond mine to continue operating in FY2016. Processing high grade stockpiles from Ellendale E4 and coarse tailings from E9. | Kimberley Diamonds Ltd., Apr. 1, 2p. | Australia | News item - press release |
DC201506-1546 2015 | Kimberley Diamonds Ltd. | Highlights Ellendale and Lerala. | Kimberley Diamonds Ltd., Apr. 30, 1p. | Australia, Africa, Botswana | News item - press release |
DC201507-1547 2015 | Kimberley Diamonds Ltd. | Market update .. Ellendale diamond mine E4 and E9. Lerala funding. | Kimberley Diamonds Ltd., May 26, 3p. | Australia, Africa, Botswana | News item - press release |
DC201507-1548 2015 | Kimberley Diamonds Ltd. | KDL subsidiary earns 50% interest in Botswana joint venture. Lerala with Tilwane | Kimberley Diamonds Ltd., June 6, 1p. | Africa, Botswana | News item - press release |
DC201508-1542 2015 | Kimberley Diamonds Ltd. | Lerala project timeline and key milestones. | Kimberley Diamonds Limited, July 24, 3p. | Africa, Botswana | News item - press release |
DC201508-1543 2015 | Kimberley Diamonds Ltd. | Lump sum turnkey contract for Lerala plant modifications excecuted. Consulmet | Kimberley Diamonds Limited, July 20, 3p. | Africa, Botswana | News item - press release |
DC201509-1549 2015 | Kimberley Diamonds Ltd. | Lerala site update. Consulmet have substantially completed the upgrade. | Kimberley Diamonds Ltd., Aug. 24, 1p. | Africa, Botswana | News item - press release |
DC201510-2352 2015 | Kimberley Diamonds Ltd. | Annual statement of mineral resources … Lerala, Ellendale, Smoke Creek. | Kimberley Diamonds Ltd., Sept. 8, 60p. | Africa, Botswana, Australia | News item - press release |
DC201510-2353 2015 | Kimberley Diamonds Ltd. | Market update - mining preparations Lerala Pit K3 de-watering. | Kimberley Diamonds Ltd., Sept. 18, 2p. | Africa, Botswana | News item - press release |
DC201511-2390 2015 | Kimberley Diamonds Ltd. | Potential for diamond bearing alluvial deposits at Lerala. | Kimberley Diamonds Limited, Oct. 16, 5p. | Africa, Botswana | News item - press release |
DC201512-2437 2015 | Kimberley Diamonds Ltd. | Final regulatory approval granted for Lerala mine re-opening. | Kimberley Diamonds Ltd., Oct. 29, 1p. | Africa, Botswana | News item - press release |
DS201503-0154 2015 | 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. | Australia | History, review Argyle |
DS201511-1853 2015 | King, S.D. | Mantle convection, the asthenosphere, and Earth's thermal history. | Geological Society of America Special Paper, No. 514, pp. SPE514-07. | Mantle | Geothermometry |
| Abstract: Calculations of mantle convection generally use constant rates of internal heating and time invariant core-mantle boundary temperature. In contrast parameterized convection calculations, sometimes called thermal history calculations, allow these properties to vary with time but only provide a single average temperature for the entire mantle. Here I consider 3D spherical convection calculations that run for the age of the Earth with heat producing elements that decrease with time, a cooling core boundary condition, and a mobile lid. The calculations begin with a moderately hot initial temperature, consistent with a relatively short accretion time for the formation of the planet. I find that the choice of a mobile or stagnant lid has the most significant effect on the average temperature as a function of time in the models. However the choice of mobile versus stagnant lid has less of an effect on the distribution of hot and cold anomalies within the mantle, or planform. I find the same low-degree (one upwelling or two upwelling) temperature structures in the mobile lid calculations that have previously been found in stagnant lid calculations. While having less of an effect on the mean mantle temperature, the viscosity of the asthenosphere has a profound effect on the pattern of temperature anomalies, even in the deep mantle. If the asthenosphere is weaker than the upper mantle by more than an order of magnitude, then the low-degree (one or two giant upwellings) pattern of temperature anomalies results. If the asthenosphere is less than an order of magnitude weaker than the upper mantle, then the pattern of temperature anomalies has narrow cylindrical upwellings and cold down going sheets. The low-degree pattern of temperature anomalies is more consistent with the plate model than the plume model (Foulger, 2007). |
DS201502-0069 2014 | Kinzie, C.R., Que Hee, S.S., Stich, A., Tague, K.A., Mercer, C., Razink, J.J., Kennett, D.J., DeCarli, P.S., Bunch, T.E., Wittke, J.H., Israde-Alantara, I., Bischoff, J.L., Goodyear, A.C., Tankersley, K.B., Kimbel, D.R., Culleton, B.J., Erlandson, J.M. | Nanodiamond-rich layer across three continents consistent with major cosmic impact at 12,800 Cal BP. | Journal of Geology, Vol. 122, Sept. pp. 475-506. | South America, Brazil | Nanodiamonds |
DS201502-0070 2015 | Kiseleva, O., Zhmodik, S. | Distribution and PGE mineralization in the formation of chromitite in ophiolite complexes ( Ospina-Kitoi Kharanur) and ultrabasic massifs of eastern Sayan, Southern Siberia. | Economic Geology Research Institute 2015, Vol. 17,, #3203, 1p. Abstract | Russia | Melting |
DS201511-1854 2015 | Kitawaki, H., Hisanaga, M., Yamamoto, M. | Type 1b yellow to brownish yellow CVD synthetic diamonds seen at CGL. | Journal of Gemmology, Vol. 34, 7, pp. 594-605. | Technology | Synthetics |
| Abstract: In mid-2012, one of the international diamond grading laboratories in Antwerp reported undisclosed CVD synthetic diamonds, causing a stir in the diamond industry (Even-Zohar, 2012). Since then, reports of undisclosed CVD synthetics have also emerged from gem testing laboratories in India and China (D’ Haenens-Johanson et al., 2013; Song et al., 2014). Central Gem Laboratory (CGL) also reported on undisclosed over 1 ct size CVD synthetic diamonds (Kitawaki et al., 2013). Gem quality CVD products have been improved in their size and quality year after year, and a variety of colours have appeared. Most of the CVD synthetic diamonds reported previously are type II, however, recently some yellow CVD synthetic diamonds containing isolated substitutional nitrogen have been supplied to the gem market (Moe et al., 2014; Hainschwang, 2014). This report describes the gemmological features of fifteen yellow to brownish yellow type Ib CVD synthetic diamonds submitted to CGL without disclosure. |
DM201510-2055 2015 | Klein, G. | Looking to Lac de Gras. | Resourceclips.com, Aug. 27, 5p. | Canada, Northwest Territories | Lac de Gras arena |
DS201509-0410 2015 | Klein, G. | New theory adds salt and water to diamond formation recipe. Ekati field | Resource Clips, Aug. 19, 1/2p. | Canada, Northwest Territories | Deposit - Fox |
| Abstract: Happening as it does deep within the Earth’s mantle, the process of creating diamonds has always been a bit murky. Laypeople understand the explanation has something to do with enormous pressure exerted on carbon. Hollywood once portrayed the process, perhaps just a tad simplistically, when it showed Superman producing a diamond by squeezing a lump of coal in his hand. But a paper published by the academic journal Nature on August 19 suggests ancient seawater played a key role, at least in the diamonds of the Northwest Territories’ Slave Craton. |
DS201503-0155 2015 | Kleinhanns, I.C., Fullgraf, T., Wilsky, F., Nolte, N., Fliegel, D., Klemd, R., Hansen, B.T. | U-Pb zircon ages and (isotope) geochemical signatures of the Kamanjab In lier ( NW Namibia): constraints on Palaeoproterozoic crustal evolution along the southern Congo craton. | Geological Society of London Special Publication: Continent formation through time., No. 389, pp. 165-195. | Africa, Namibia | Geochemistry |
DS201510-1777 2014 | Koctizin, Yr.A. | Trace element composition of primitive mantle - non-chondrite model. | Deep-seated magmatism, its sources and plumes, Proceedings of XIII International Workshop held 2014., Vol. 2014, pp. 39-65. | Mantle | Geochronology - isotope data |
DS201510-1778 2015 | Kogarko, L.N. | Fractionation of zirconium and hafnium during evolution of a highly alkaline magmatic system, Lovozero massif, Kola Peninsula. | Doklady Earth Sciences, Vol. 463, 2, pp. 792-794. | Russia, Kola Peninsula | Lovozero Masdif |
DS201510-1779 2014 | Kogarko, L.N. | Geochemical features of radioactive elements in ultramafic-alkaline rocks ( example - largest in the globe Guli complex). | Deep-seated magmatism, its sources and plumes, Proceedings of XIII International Workshop held 2014., Vol. 2014, pp. 22-31. | Russia, Siberia | Deposit - Guli Complex |
DS201511-1855 2015 | Kolb, J., Bagas, L., Fiorentini, M.L. | Metallogeny of the North Atlantic Craton in Greenland. ( not specific to diamonds). | Mineralogical Magazine, Vol. 79, 4, pp. 815-855. | Europe, Greenland | Metallogeny |
| Abstract: The North Atlantic Craton (NAC) extends along the coasts of southern Greenland. At its northern and southern margins, Archaean rocks are overprinted by Palaeoproterozoic orogeny or overlain by younger rocks. Typical granite-greenstone and granite-gneiss complexes represent the entire Archaean, with a hiatus from ~3.55-3.20 Ga. In the granulite- and amphibolite-facies terranes, the metallogeny comprises hypozonal orogenic gold and Ni-PGE-Cr-Ti-V in mafic-ultramafic magmatic systems. Gold occurrences are widespread around and south of the capital, Nuuk. Nickel mineralization in the Maniitsoq Ni project is hosted in the Norite belt; Cr and PGE in Qeqertarssuatsiaq, and Ti-V in Sinarsuk in the Fiskenæsset complex. The lower-grade metamorphic Isua greenstone belt hosts the >1000 Mt Isua iron deposit in an Eoarchaean banded iron formation. Major Neoarchaean shear zones host mesozonal orogenic gold mineralization over considerable strike length in South-West Greenland. The current metallogenic model of the NAC is based on low-resolution data and variable geological understanding, and prospecting has been the main exploration method. In order to generate a robust understanding of the metal endowment, it is necessary to apply an integrated and collective approach. The NAC is similar to other well-endowed Archaean terranes but is underexplored, and is therefore likely to host numerous targets for greenfields exploration. |
DS201512-1935 2015 | Kon, Y., Araoka, D., Ejima, T., Hirata, T. | Rapid and precise determination of major and trace elements in CCRMP and USGS geochemical reference samples using femtosecond laser ablation ICP-MS. | Symposium on critical and strategic materials, British Columbia Geological Survey Paper 2015-3, held Nov. 13-14, pp. 245-250. | Technology | Carbonatite |
| Abstract: We measured 10 major (SiO2, TiO2, Al2O3, total Fe2O3, MnO, MgO, CaO, Na2O, K2O, and P2O5) and 32 trace (Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Cs, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Pb, Th, and U) elements in 16 geochemical reference samples (AGV-1, AGV-2, BCR-1, BCR- 2, BHVO-2, BIR-1a, DNC-1a, G-2, GSP-1, GSP-2, MAG-1, QLO-1, RGM-1, RGM-2, SGR-1b, and STM-1) distributed by United States Geological Survey (USGS) and three reference rock samples (SY-2, SY-3, and MRG-1) provided by Canadian Certifi ed Reference Materials Project (CCRMP) using inductively coupled plasma -mass spectrometry coupled with the femtosecond laser ablation sample introduction technique (fsLA-ICP-MS). Before the elemental analysis, fused glassbeads were prepared from the mixture of sample powder and high-purity alkali fl ux with a mixing ratio of 1:10. The abundances of the major and trace elements were externally calibrated by using glass beads containing the major and trace elements prepared from 17 Geological Survey of Japan (GSJ) geochemical reference samples (JB-1, JB-1a, JB-2, JB-3, JA-1, JA-2, JA-3, JR-1, JR-2, JR-3, JP-1, JGb-1, JGb-2, JG-1a, JG- 2, JG-3, and JSy-1). Typical analysis repeatabilities for these geochemical reference samples were better than 3% for Al2O3 and Na2O; <5% for SiO2, TiO2, total Fe2O3, MnO, MgO, CaO, K2O, P2O5, Zn, Rb, Sr, Zr, Nb, Ba, Nd, and U; <8% for Sc, V, Cr, Co, Y, Cs, La, Ce, Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Pb, and Th; <11% for Ni and Cu. These data clearly demonstrate that high analytical repeatability can be achieved by the fsLA-ICP-MS technique with glass beads made from 0.5 g larger samples. |
DS201506-0282 2015 | Koptev, A., Calais, E., Burov, E., Leroy, S., Gerya, T. | Dual continental rift systems generated by plume-lithosphere interaction. Central East African Rift | Nature Geoscience, Vol. 8, pp. 388-392. | Africa | Magmatism |
DS201510-1780 2015 | Korsakov, A.V., Zhimuev, E.I., Mikhailenko, D.S., Demin, S.P., Kozmenko, O.A. | Graphite pseudomorphs after diamonds: an experimental study of graphite morphology and the role of H2O in the graphitization process. | Lithos, Vol. 236-237, pp. 16-26. | Technology | Graphite |
DS201503-0156 2015 | Kotkova, J., Janak, M. | UHP kyanite eclogite associated with garnet peridotite and diamond bearing granulite, northern Bohemian Massif. | Lithos, Vol. 226, pp. 255-264. | Europe | Bohemian |
DS201503-0157 2015 | Kozlov, E.N., Arzamastsev, A.A. | Petrogenesis of metasomatic rocks in the fenetized zones of the Ozernaya Varaka alkaline ultrabasic complex Kola Peninsula. | Petrology, Vol. 23, 1, pp. 45-67. | Russia, Kola Peninsula | Alkalic |
DS201509-0411 2015 | Krupchatnikov, V.I., Vrublevskii, V.V., Kruk, N.N. | Early Mesozoic lamproites and monzonitoids of southeastern Gorny Altai: geochemistry, Sr-Nd isotope composition, and sources of melts. | Russian Geology and Geophysics, Vol. 56, pp. 825-843. | Russia | Chuya Complex |
| Abstract: Small intrusions of lamprophyres and lamproites (Chuya complex) and K-monzonitoids (Tarkhata and Terandzhik complexes) are widespread in southeastern Gorny Altai. Geochronological (U-Pb and Ar-Ar) isotope studies show their formation in the Early-Middle Triassic (~ 234-250 Ma). Lamproites have been revealed within two magmatic areas and correspond in geochemical parameters to the classical Mediterranean and Tibet orogenic lamproites. According to isotope data ((87Sr/86Sr)T = 0.70850-0.70891, (143Nd/144Nd)T = 0.512157-0.512196, 206Pb/204Pb = 17.95-18.05) and Th/La and Sm/La values, the Chuya lamproites and lamprophyres melted out from the enriched lithospheric mantle with the participation of DM, EM1, EM2, and SALATHO. The monzonitoid series of the Tarkhata and Terandzhik complexes are similar in petrographic and geochemical compositions but differ significantly in Sr-Nd isotope composition: The Tarkhata monzonitoids are close to the Chuya lamproites, whereas the Terandzhik ones show a higher portion of DM ((87Sr/86Sr)T = 0.70434-0.70497, (143Nd/144Nd)T = 0.512463-0.512487) in their source, which suggests its shallower depth of occurrence and the higher degree of its partial melting as compared with the derivates of the Chuya and Tarkhata complexes. The studied rock associations tentatively formed in the postcollisional setting under the impact of the Siberian superplume. |
DS201511-1856 2015 | Kryvoshlyk, Igor | Mathematical calculations of kimberlite diamond grade. | Kryvoshlyk, 38ppt. Available ppt. Email ikryvoa481 @hotmail.com | Technology | Microdiamonds - responses |
| Abstract: Diamond grade is the most important parameter of a kimberlite rock. A few hundreds of microprobe analyses of garnets picked randomly from a kimberlite concentrate might be enough to calculate mathematically accurate diamond grade. |
DS201511-1857 2015 | Kryvoshlyk, Igor | Kimberlite diamond grade ( actual projects and numbers) | Kryvoshlyk, 18ppt. Available ppt. email ikryvoa481 @hotmail.com | Technology | Microdiamonds - responses |
DS201502-0071 2015 | 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. | Technology | Diamond inclusions |
DS201511-1858 2013 | Kvasnytsya, V. | Crystal forms of natural microdiamonds. | Diamond and Related Materials, Vol. 39, pp. 89-97. | Technology | Microdiamonds - responses |
| Abstract: Geometrical crystallographic features of rare diamond micro-crystals (0.3-0.5 mm in diameter) from kimberlites having different complex flat and smooth faces are described. Such polyhedrons of microdiamonds are typically composed of two or more combinations of seven different crystal forms belonging to hexoctahedral symmetry class: octahedron, cube, rhombic dodecahedron, trisoctahedron, trapezohedron, tetrahexahedron and hexoctahedron. Many of them are not yet known for macro-crystals of this mineral. All these forms are found as small faces on the octahedral crystals. Both flat and smooth faces of octahedron and cube on such crystals have their own growth sectors. Flat faces of rhombic dodecahedron, different trisoctahedrons, trapezohedrons and hexoctahedrons occur as so-called faces of degeneration of octahedral growth planes. Nature of tetrahexahedron flat faces is not clear. An investigation of the complex diamond polyhedrons should give a new idea on crystal morphology of diamond, make more precise its symmetry and be important for the explanation of the nature of diamond on the whole. |
DM201505-0886 2015 | Kwantes, J. | Comments on Peregrine Diamonds. Positive | Resource Opportunities, Apr. 21, 1/4p. | Canada, Nunavut, Baffin Island | News item - Peregrine |
DS201510-1781 2015 | Kyser, K., Barr, J., Ihlenfeld, C. | Applied geochemistry in mineral exploration and mining. | Elements, Vol. 11, Aug. pp. 241-246. | Technology | Not specific to diamonds |
| Abstract: The prosperity of our societies and our standards of living are directly related to our ability to find, exploit, and manage our metal and mineral resources. Metal and mineral deposits are, in fact, geochemical anomalies and, as such, applied geochemistry plays a critical role throughout the mineral resources value chain, from early stage exploration to mine closure. The fundamentals of element mobility (i.e. transport and fixation) in the near-surface environment are used by geochemists to detect mineral deposits at depth, reveal element distributions in and around deposits, assess the total geochemical environment, and refine effective and benign extraction and waste disposal techniques. Both pure- and applied-research ventures play fundamental roles in providing the techniques to manage metal resources and thereby benefit society. |
DM201508-0887 2015 | Laniado, E.A. | Forging a path ahead for the diamond market. | info @ehudlaniado.com, July 6, 3p. | Global | News item - markets |
DS201510-1782 2015 | Lavrentev, Yu.G., Karmanov, N.S., Usova, L.V. | Electron probe microanalysis of minerals: micranalyzer or scanning electron microscope? | Russian Geology and Geophysics, Vol. 56, pp. 1154-1161. | Technology | Spectrometry |
| Abstract: The results of electron probe microanalysis of several rock-forming minerals by wavelength-dispersive spectrometry (WDS) and energy-dispersive spectrometry (EDS) are compared, and the metrological characteristics of both methods are studied. The measurements were made with the use of a JXA-8100 (JEOL) microanalyzer with five wavelength-dispersive spectrometers and a MIRA 3 LMU (Tescan) scanning electron microscope equipped with an INCA Energy 450 XMax 80 (Oxford Instruments) microanalysis system. Specimens with olivine, garnet, pyroxene, ilmenite, and Cr-spinel grains were analyzed.
The variation coefficients that characterize the repeatability of a single determination are found to be ~ 0.5% for WDS and ~ 0.9% for EDS in the compositional range of the main components (C > 10%). For minor components (1% < C < 10%), the variation coefficients are 1.4% and 3.0%, respectively, and for impurities (0.3% < C < 1%), 2.7% and 13%, respectively. For lower contents EDS is almost inapplicable. The ratio of the results obtained by the two methods is reproduced with high precision: For major components, the variation coefficient is 0.56%; for minor components, 1.7%; and even for impurities, it is ~ 8%. The magnitude of the bias is between 0.2 and 3.2 rel.%, which is acceptable.
The results show that the accuracies of WDS and EDS are similar for measuring major and minor components of rock-forming minerals. Energy-dispersive spectrometry is inferior to wavelength-dispersive spectrometry for impurities and is completely inapplicable for still lower contents. This method is easier to implement, and the results are available soon after switching on the instrument. Wavelength-dispersive spectrometry needs more time for preparation, but it ensures a precise high-efficiency large-scale analysis of samples of similar compositions, even when the element contents are lower than 1%. |
DS201507-0320 2015 | Lazereva, E.V., Zhmodik, S.M., Dobretsov, N.L., Tolstov, A.V., Shcherbov, B.L., Karmanov, N.S., Gerasimov, E.Yu., Bryanskaya, A.V. | Main minerals of abnormally high grade ores of the Tomtor deposit ( Arctic Siberia). | Russian Geology and Geophysics, Vol. 56, pp. 844-873. | Russia | Deposit - Tomtor |
DS201509-0412 2015 | Le Losq, C., Mysen, B.O., Cody, G.D. | Water and magmas: insights about the water solution mechanisms in alkali silicate melts from infrared, Raman, and 29 Si solid-state NMR spectroscopies. | Progress in Earth and Planetary Science, Vol. 2, 22p. | Mantle | Magmatism |
| Abstract: Degassing of water during the ascent of hydrous magma in a volcanic edifice produces dramatic changes in the magma density and viscosity. This can profoundly affect the dynamics of volcanic eruptions. The water exsolution history, in turn, is driven by the water solubility and solution mechanisms in the silicate melt. Previous studies pointed to dissolved water in silicate glasses and melts existing as molecules (H 2 O mol species) and hydroxyl groups, OH. These latter OH groups commonly are considered bonded to Si 4+ but may form other bonds, such as with alkali or alkaline-earth cations, for instance. Those forms of bonding influence the structure of hydrous melts in different ways and, therefore, their properties. As a result, exsolution of water from magmas may have different eruptive consequences depending on the initial bonding mechanisms of the dissolved water. However, despite their importance, the solution mechanisms of water in silicate melts are not clear. In particular, how chemical composition of melts affects water solubility and solution mechanism is not well understood. In the present experimental study, components of such information are reported via determination of how water interacts with the cationic network of alkali (Li, Na, and K) silicate quenched melts. Results from 29 Si single-pulse magic-angle spinning nuclear magnetic resonance ( 29 Si SP MAS NMR), infrared, and Raman spectroscopies show that decreasing the ionic radius of alkali metal cation in silicate melts results in decreasing fraction of water dissolved as OH groups. The nature of OH bonding also changes as the alkali ionic radius changes. Therefore, as the speciation and bonding of water controls the degree of polymerization of melts, water will have different effects on the transport properties of silicate melts depending on their chemical composition. This conclusion, in turn, may affect volcanic phenomena related to the viscous relaxation of hydrous magmas, such as for instance the fragmentation process that occurs during explosive eruptions. |
DS201508-0362 2015 | Lee, C-T.A., Anderson, D.L. | Continental crust formation at arcs, the arclogite "delamination" cycle, and one origin for fertile melting anomalies in the mantle. | Science Bulletin, DOI: 10.1007/s11434-015-088-6 online 16p. | Mantle | Eclogite |
DS201508-0363 2015 | Lee, C-T.A., McKenzie, N.R. | Geochemistry: rise of the continents. | Nature Geoscience, Vol. 8, pp. 506-507. | Mantle | Plate Tectonics |
DS201502-0072 2015 | 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 Africa | Deposit - Finsch |
DS201511-1859 2014 | Lee, J.A., Caudill, S.B., Mixon, F.G.Jr. | Shine bright like a diamond: a hedonic model of grading and pricing an experience good. ( diamonds) | Applied Economics, Vol. 46, 16, pp. 1829-1838. | Global | Diamond market |
| Abstract: Diamonds are generally evaluated on the basis of sensory characteristics, such as carat (weight), colour, clarity and cut. However, given the experience goods nature of diamonds, few consumers grasp how the sensory characteristics of these stones are evaluated by the gemological grading laboratories that independently issue diamond reports. This study extends prior research by determining whether diamonds graded by certain gemological laboratories are subject to pricing premiums or discounts in online retail markets. Regression models employing a sample of 169 483 real-time diamond offerings from online diamond retailers (e.g. Blue Nile, James Allen and Adiamor) find significant price discounts attributable to diamonds graded by the European Gemological Laboratory USA in relation to diamonds graded by the Gemological Institute of America (GIA) and significant price premiums attributable to diamonds graded by the American Gem Society in relation to diamonds graded by the GIA. |
DS201502-0073 2015 | Lee, S., Suh, J., Park, H-D. | BoreholeAR: a mobile tablet application for effective borehole database visualization using an augmented reality technology. | Computers & Geosciences, Vol. 76, pp. 41-49. | Technology | Not specific to diamonds |
DC201509-1550 2015 | Lemarne Corporation Limited | Signed two non-binding heads of agreement with Central Kimberley Diamonds ( CKD) and Unique Sapphires Pty. Ltd. ( an interest in Palmietfontein diamond project. | Lemarne Corporation Limited, Aug. 18, 3p. | Africa, South Africa | News item - press release |
DS201508-0364 2015 | Li, H., Zhang, Z., Ernst, R., Lu, L., Santosh, M., Zhang, D., Cheng, Z. | Giant radiating mafic dyke swarm of the Emeishan Large Igneous Province: identifying the mantle plume centre. | Terra Nova, Vol. 27, 4, pp. 247-257. | China | Mantle plume |
DS201507-0321 2015 | Li, M., McNamara, A.K. | The difficulty for subducted oceanic crust to accumulate at the Earth's core-mantle boundary. | Journal of Geophysical Research, Vol. 118, 4, pp. 1807-1816. | Mantle | Subduction |
DS201511-1860 2014 | Linton, T., Paul, A. | Cultj diamond selector IIItm. ( jewellery stores) | Australian Gemmologist, Vol. 24, 2, pp. 46-47. | Technology | Diamond tester |
DS201507-0322 2015 | Liu, J., Scott, J.M., Martin, C.E., Pearson, D.G. | The longevity of Archean mantle residues in the convecting upper mantle and their role in young continent formation. | Earth and Planetary Science Letters, Vol. 424, pp. 109-118. | Mantle | Convection |
DS201511-1861 2015 | Liu, L. | The ups and downs of North America: evaluating the role of mantle dynamic topography since the Mesozoic. | Reviews of Geophysics, Vol. 53, 3, pp. 1022-1049. | Canada, United States | Geodynamics |
| Abstract: The driving force for transient vertical motions of Earth's surface remains an outstanding question. A main difficulty lies in the uncertain role of the underlying mantle, especially during the geological past. Here I review previous studies on both observational constraints and physical mechanisms of North American topographic evolution since the Mesozoic. I first summarize the North American vertical motion history using proxies from structural geology, geochronology, sedimentary stratigraphy, and geomorphology, based on which I then discuss the published physical models. Overall, there is a progressive consensus on the contribution of mantle dynamic topography due to buoyancy structures associated with the past subduction. At the continental scale, a largely west-to-east migrating deformation pattern suggests an eastward translation of mantle dynamic effects, consistent with models involving an eastward subduction and sinking of former Farallon slabs since the Cretaceous. Among the existing models, the inverse model based on an adjoint algorithm and time-dependent data constraints provides the most extensive explanations for the temporal changes of North American topography since the Mesozoic. At regional scales, debates still exist on the predicted surface subsidence and uplift within both the western and eastern United States, where discrepancies are likely due to differences in model setup (e.g., mantle dynamic properties and boundary conditions) and the amount of time-dependent observational constraints. Toward the development of the next-generation predictive geodynamic models, new research directions may include (1) development of enhanced data assimilation capabilities, (2) exploration of multiscale and multiphysics processes, and (3) cross-disciplinary code coupling. |
DS201508-0365 2015 | Liu, Xi, Zhong, Shijie | The long wave length geoid from three dimensional spherical models of thermal and thermochemical mantle convection. | Journal of Geophysical Research, Vol. 120, 6, pp. 4572-4596. | Mantle | Geothermometry |
DS201508-0366 2015 | Liu, Y., Chen, Z., Yang, Z., Sun, X., Zhu, Z., Zhang, Q. | Mineralogical and geochemical studies of brecciated ores in the Dalucao REE deposit, Sichuan Province, southwestern China. | Ore Geology Reviews, Vol. 70, pp. 613-636. | China | Carbonatite |
DS201502-0074 2015 | Logvinova, A.M., Taylor, L.A., Fedorova, E.N., Yelisseyev, A.P., Wirth, R., Howarth, G., Reutsky, V.N., Sobolev, N.V. | A unique Diamondiferous peridoite xenolith from the Udachnaya kimberlite pipe, Yakutia: role of subduction in diamond formation. | Russian Geology and Geophysics, Vol. 56, 1, pp. 306-320. | Russia, Yakutia | Deposit - Udachnaya |
DS201501-0031 2014 | Lollar, B.S., Onstott, T.C., Lacrampe-Couloume, G., Ballentine, C.J. | The contribution of the Precambrian continental lithosphere to global H2 production. | Nature, Vol. 516, Dec. 18, pp. 379-382. | Mantle | Hydrogeology |
DS201502-0075 2014 | Lollar, S. | Ancient, hydrogen rich waters discovered deep underground at locations around the world. | Nature, Vol. 516, pp. 379-382. | Canada, Africa, South Africa, Europe, Scandinavia | Chemistry - water |
DS201510-1783 2015 | Lombard, L. | Threat economies and armed conservation in northeastern Central African Republic. | Geoforum, in press available | Africa, Central African Republic | CSR |
| Abstract: This article, based on ethnographic and archival research in the northeastern parklands of the Central African Republic (CAR), explores the area’s history of armed conservation. Critical scholarly accounts of armed conservation practices and projects often starkly contrast the people involved in them: there are agents of the state, or state-like actors, who seek to dominate, territorialize, and discipline, often using violence to do so, and there are local populations who are dispossessed of their lands and resources without compensation and forced into new kinds of poverty, despite rhetoric and practices meant to inculcate "local participation". The case presented here forces us to re-think these accounts. Rather than pursuing authority in the sense of expanding control over other people, people in northeastern CAR (whether putatively in favor of or opposed to conservation) are working to create and maintain access to the status of an income. To do so they engage in practices of threatening and hiding. While the means to use physical force are not equally shared, capacities to threaten and hide are widely held, and organizational and other hierarchies are unstable, making it difficult to describe any of this as a matter of domination and resistance. Expanding on literature that examines processes of green militarization (Lunstrum, 2014), the article focuses on the interactional dynamics of armed conservation to show that threats are as important as acts of physical violence, and that hiding-whether in the bush or plain sight-is critical to understanding armed conservation in an area where the state is largely seen as absent. |
DM201507-0888 2015 | London Mining Journal | Botswana, diamonds and the Russian connection. John Teeling comments. | London Mining Journal, June 3, 1/2p. | Africa, Botswana | News item - Connemara |
DM201508-0889 2015 | London Mining Journal | Alrosa Grib grab could be nearer. ( Grib sits inside a giant oil company ) | London Mining Journal, July 7, 1/4p. | Russia | News item - Grib |
DM201510-2056 2015 | London Mining Journal | Synthetics' impact not clear-cut. | London Mining Journal, Sept. 14, 1/2p. | Global | News item - synthetics |
DM201511-2150 2015 | London Mining Journal | Diamonds in the rough… Anglo American, courtesy of De Beers division, is in the news today thanks to a poor outlook for diamonds, but the company with the bigger problem is the world's third biggest diamond miner, Rio Tinto. | London Mining Journal, Oct. 22, 1p. | Global | News item - De Beers, Rio Tinto |
DM201512-2327 2015 | London Mining Journal | William Lamb has been named CEO of the year. | London Mining Journal, Oct. 29, 1/2p. | Africa, Botswana | News item - Lucara |
DS201505-0238 2015 | Loomis, I. | Earth's tectonic plates skitter about. | Sciencemag.org, Mar. 20, 1p. | Global | Geodynamics |
DS201506-0283 2015 | Loranov, S.S., Goncharov, A.F., Litasov, K.D. | Optical properties of siderite ( FeCo3) across the spin transition: crossover to iron rich carbonates in the lower mantle. | American Mineralogist, Vol. 100, pp. 1059-1064. | Mantle | Subduction |
DS201503-0158 2015 | Lu, G., Kaus, B.J.P., Zhao, L., Zheng, T. | Self-consistent subduction initiation induced by mantle flow. | Terra Nova, Vol. 27, 2, pp. 130-138. | Mantle | Subduction |
DC201502-1551 2015 | Lucapa Diamond Company | Diamond mining results at Lulo. | Lucapa Diamond Company, Jan 22, 3p. | Africa, Angola | News item - press release |
DC201504-1552 2015 | Lucapa Diamond Company | Lucapa prepares to mine high grade diamond areas at Lulo. | Lucapa Diamond Company, Mar. 10, 4p. | Africa, Angola | News item - press release |
DC201505-1553 2015 | Lucapa Diamond Company | Lucapa steps up kimberlite diamond program at Lulo. L46 and E46 | Lucapa Diamond Company, Mar. 23, 2p. | Africa, Angola | News item - press release |
DC201505-1554 2015 | Lucapa Diamond Company | Chairman's summary of year to date … Lulo | Lucapa Diamond Company, Apr. 1p. | Africa, Angola | News item - press release |
DC201505-1555 2015 | Lucapa Diamond Company | Lucapa exceeds diamond mining and processing targets. 1,335 carats. Lulo | Lucapa Diamond Company, Apr. 8, 5p. | Africa, Angola | News item - press release |
DC201505-1556 2015 | Lucapa Diamond Company | Large 63 carat type 11a diamond recovered at Lulo. | Lucapa Diamond Company, Apr. 16, 3p. | Africa, Angola | News item - press release |
DC201508-1557 2015 | Lucapa Diamond Company | New fleet arrives to scale up diamond mining at Lulo. | Lucapa Diamond Company, June 30, 2p. | Africa, Angola | News item - press release |
DC201508-1558 2015 | Lucapa Diamond Company | Lucapa is pleased to announce the Lulo diamond project achieved its monthly processing target of 10,000 bulk cubic metres for the month of June. | Lucapa Diamond Company, July 6, 3p. | Africa, Angola | News item - press release |
DC201509-1559 2015 | Lucapa Diamond Company | Diamond mining licence expanded at Lulo. | Lucapa Diamond Company Limited, Aug. 6, 3p. | Africa, Angola | News item - press release |
DC201509-1560 2015 | Lucapa Diamond Company | More large diamonds at Lulo. | Lucapa Diamond Company Limited, Aug. 18, 4p. | Africa, Angola | News item - press release |
DC201510-2354 2015 | Lucapa Diamond Company | More large valuable diamonds at Lulo 40.59 ( type IIa) | Lucapa Diamond Company, Sept. 15, 3p. | Africa, Angola | News item - press release |
DC201510-2355 2015 | Lucapa Diamond Company | Lulo diamonds sell for $ 1.02 million. | Lucapa Diamond Company, Sept. 14, 2p. | Africa, Angola | News item - press release |
DC201511-2391 2015 | Lucapa Diamond Company | 74.5 carat diamond among more large recoveries at Lulo. L259 kimberlite | Lucapa Diamond Company, Oct. 19, 3p. | Africa, Angola | News item - press release |
DC201512-2438 2015 | Lucapa Diamond Company | Lulo diamonds sell for $A 2.1 million. | Lucapa Diamond Corporation, Nov. 16, 1p. | Africa, Angola | News item - press release |
DC201512-2439 2015 | Lucapa Diamond Company | Lucapa Diamond to explore L259and L13/15 kimberlites. | Lucapa Diamond Corporation, Nov. 23, 1p. | Africa, Angola | News item - press release |
DC201501-1561 2014 | Lucara Diamond Corporation | Provides operating outlook for 2015. Karowe | Lucara Diamond Corporation, Dec. 8, 2p. | Africa, Botswana | News item - press release |
DC201502-1562 2014 | Lucara Diamond Corporation | Lucara announces decision on Mothae. | Lucara Diamond Corporation, Dec. 22, 1p. | Africa, Lesotho | News item - press release |
DC201502-1563 2014 | Lucara Diamond Corporation | Lucara announces corporate change. George leaving. | Lucara Diamond Corporation, Dec. 31, 1p. | Africa, Botswana | News item - press release |
DC201503-1564 2015 | Lucara Diamond Corporation | Lucara declares special dividend on strong 2014 performance. Karowe | Lucara Diamond Corporation, Feb. 18, 1p. | Africa, Botswana | News item - press release |
DC201505-1565 2015 | Lucara Diamond Corporation | Lucara recovers 342 carat diamond at its Karowe mine. | Lucara Diamond Corporation, Apr. 20, 2p. | Africa, Botswana | News item - press release |
DC201506-1566 2015 | Lucara Diamond Corporation | Lucara enters into a memorandum of understanding to sell Mothae. | Lucara Diamond Corporation, May 4, 1p. | Africa, Lesotho | News item - press release |
DC201506-1567 2015 | Lucara Diamond Corporation | First quarter results: Lucara on schedule to complete plant optimization and to process South Lobe ore. ( Karowe) | Lucara Diamond Corporation, May, 12, 6p. | Africa, Botswana | News item - press release |
DC201506-1568 2015 | Lucara Diamond Corporation | Exceptional stone tender announced. Karowe | Lucara Diamond Corporation, May 26, 1p. | Africa, Botswana | News item - press release |
DC201508-1569 2015 | Lucara Diamond Corporation | Lucara's exceptional stone tender. Karowe | Lucara Diamond Corporation, July 16, 1p. | Africa, Botswana | News item - press release |
DC201509-1570 2015 | Lucara Diamond Corporation | Lucara reports strong Q2 performance and updates on the plant optimization project. Karowe | Lucara Diamond Corporation, Aug. 11, 3p. | Africa, Botswana | News item - press release |
DC201509-1571 2015 | Lucara Diamond Corporation | Lucara reports ongoing recovery of exceptional diamonds. Karowe 336, 184, 94, 86 carats stones. | Lucara Diamond Corporation, Aug. 17, 2p. | Africa, Botswana | News item - press release |
DC201510-2356 2015 | Lucara Diamond Corporation | Lucara announces dates for second exceptional stone tender. Nov. 2-11. Karowe | Lucara Diamond Corporation, Sept. 8, 2p. | Africa, Botswana | News item - press release |
DC201511-2392 2015 | Lucara Diamond Corporation | Lucara provides exploration update. Karowe and BK02, AK11 and AK12. | Lucara Diamond Corporation, Oct. 15, 1p. | Africa, Botswana | News item - press release |
DC201512-2440 2015 | Lucara Diamond Corporation | Lucara generates strong quarterly cash flow and significant operating margins. Karowe | Lucara Diamond Corporation, Nov. 5, 5p. | Africa, Botswana | News item - press release |
DC201512-2441 2015 | Lucara Diamond Corporation | Lucara adds $ US 30 million to 2015 revenue from latest exceptional stone tender. | Lucara Diamond Corporation, Nov. 12, 1p. | Africa, Botswana | News item - press release |
DC201512-2442 2015 | Lucara Diamond Corporation | Lucara makes diamond history; recovers 1,111 carat diamond. | Lucara Diamond Corporation, Nov. 18, 1p. | Africa, Botswana | News item - press release |
DS201508-0367 2015 | Luguet, A., Behrens, M., Pearson, D.G., Konig, S., Herwartz, D. | Significance of the whole rock Re-Os ages in cryptically and modally metasomatized cratonic peridotites: constraints from HSE-Se-Te systematics. | Geochimica et Cosmochimica Acta, Vol. 164, pp. 441-463. | Africa, Botswana | Deposit - Letlhakane |
DS201511-1862 2015 | Lustrino, M., Anderson, D.L. | The mantle isotopic printer: basic mantle plume geochemistry for seismologists and geodynamicists. | Geological Society of America Special Paper, No. 514, pp. SPE514-16. | Mantle | Physics |
| Abstract: High-temperature geochemistry combined with igneous petrology is an essential tool to infer the conditions of magma generation and evolution in the Earth’s interior. During the last thirty years a large number of geochemical models of the Earth, essentially inferred from the isotopic composition of basaltic rocks, have been proposed. These geochemical models have paid little attention to basic physics concepts, broad-band seismology, or geological evidence, with the effect of producing results that are constrained more by assumptions than by data or first principles. This may not be evident to seismologists and geodynamicists. A common view in igneous petrology, seismology and mantle modelling is that isotope geochemistry (e.g., the Rb-Sr, Sm-Nd, U-Th-Pb, U-Th-He, Re-Os, Lu-Hf, and other more complex systems) has the power to identify physical regions in the mantle, their depths, their rheological behaviour and the thermal conditions of magma generation. We demonstrate the fallacy of this approach and the model-dependent conclusions that emerge from unconstrained or poorly constrained geochemical models that do not consider physics, seismology (other than teleseismic travel time tomography and particularly compelling colored mantle cross sections) and geology. Our view may be compared with computer printers. These can reproduce the entire range of colors using a limited number of basic colors (black, magenta, yellow, and cyan). Similarly, the isotopic composition of oceanic basalts and nearly all their primitive continental counterparts can be expressed in terms of a few mantle end-members. The four most important (actually "most extreme", since some are extraordinarily rare) mantle end-members identified by isotope geochemists are DMM or DUM [Depleted MORB (mid-ocean-ridge basalt) Mantle or Depleted Upper Mantle], HiMu (High-Mu, where Mu = ? = 238U/204Pb), EMI and EMII (Enriched Mantle type I and type II). Other mantle end-members, or components, have been proposed in the geochemical literature (e.g., PHeM, FoZo, LVC, PreMa, EMIII, CMR, LoMu, and C) but these can be considered to be less extreme components or mixtures in the geochemical mantle zoo. Assuming the existence of these extreme "colors" in the mantle isotopic printer, the only matter for debate is their location in the Earth’s interior. At least three need long-time insulation from convection-driven homogenization or mixing processes. In other words, it needs to be defined where these extreme isotopic end-members are located. In our view, no geochemical, geological, geophysical and physical arguments require the derivation of any basalt or magma from the deep mantle. Arguments to the contrary are assumption-based. The HiMu, EMI and EMII end-members can be entirely located in the shallow non-convecting volume of the mantle, while the fourth, which is by far the more abundant volumetrically, (DMM or DUM) can reside in the Transition Zone. This view is inverted compared with current canonical geochemical views of the Earth’s mantle, where the shallowest portions are assumed to be DMM-like (ambient mantle) and the EMI-EMII-HiMu end-members are assumed to be isolated, located in the deep mantle, and associated with thermal anomalies. We argue that the ancient, depleted signatures of DMM imply long-term isolation from recycling and crustal contamination while the enriched components are not free of contamination by shallow materials and can therefore be shallow. |
DS201504-0206 2015 | Luth, R.W., Stachel, T. | The buffering capacity of lithospheric mantle: implications for diamond formation. | Contributions to Mineralogy and Petrology, Vol 168, 12p. | Mantle | Oxygen barometry |
DS201508-0368 2015 | Lyalina, L., Zolotarev, A.Jr., Selivanova, E., Savchenko, Ye., Zozulya, D., Krivovichev, S., Mikhailova, Yu. | Structural characterization and composition of Y-rich hainite from Sakharojok nepheline syenite pegmatite ( Kola Peninsula, Russia). | Mineralogy and Petrology, Vol. 109, 4, pp. 443-451. | Russia, Yakutia | Nepheline syenite |
DM201502-0890 2014 | Macauhub | Sale of diamonds earns Angola US$ 1.2 billion | Macauhub/AO, Dec. 26, 1/4p. | Africa, Angola | News item - economics |
DM201502-0891 2015 | Macauhub | Angola expects important discovery of diamond deposits ( Alrosa and Endiama). | Macauhub/AO, Jan. 22, 1p. | Africa, Angola | News item - Endiama |
DM201503-0892 2015 | Macauhub | Angola mines 10 million carats of diamonds in 2014 ( worth 1.6 billion. | Macauhub.com, Feb. 12, 1/4p. | Africa, Angola | News item - Endiama |
DM201504-0893 2015 | Macauhub | Angolan government grants new artisanal diamond mining rights. Between Lunda Norte and Lunda Sul. | Macauhub.com.mo, Mar. 12, 1/4p. | Africa, Angola | News item - legal |
DM201506-0894 2015 | Macauhub | Revenue from sale of diamonds in Angola grows 8.8 % in January/February. 1.4 million carats sold for $US 195.7 million. | Macauhub.com, Apr. 23, 1/4p. | Africa, Angola | News item - economics |
DM201509-0895 2015 | Macauhub | Diamond sales increase by 35% in Angola. Tchiuzo, Luaxe, Kimangue | Macauhub.com, Aug. 3, 1/4p. | Africa, Angola | News item - production |
DM201511-2151 2015 | Macauhub | Chairman of Angola's Endiama's proposes more commercial promotion of diamonds. | macauhub.com, Oct. 8, 1/4p. | Africa, Angola | News item - Endiama |
DM201512-2259 2015 | Macauhub | Diamond sales in Angola total US$99 million in September. | macauhub.com, Nov. 4, 1/4p. | Africa, Angola | News item - Endiama |
DS201503-0159 2015 | MacGregor, D. | The Fairway concept and chance mapping: African petroleum and carbonatite examples. | PDAC 2015, Abstract, 1p. | Africa, East Africa | Carbonatite |
DS201509-0414 2015 | Macgregor, I.D. | Empirical geothermometers and geothermobarometers for spinel peridotite phase assemblages. | International Geology Review, Vol. 57, 15, pp. 1940-1974. | Technology | Peridotite, experimental petrology |
| Abstract: Experimental synthesis of spinel peridotite phase assemblages for a range of compositions that mimic natural samples is used to derive a set of empirical geothermometers and geothermobarometers represented by multiple linear regression best-fit surfaces that link the variables of temperature, pressure, and composition. The calibrated geothermometers use reactions that govern the solubility of Al and Cr in both pyroxenes and the Mg–Fe exchange between silicates and spinel. Geothermobarometers map the Mg–Fe exchange between coexisting olivine and clinopyroxene and pyroxenes and Ca–Mg exchange between coexisting pyroxenes. Application of the geothermometers and geothermobarometers to suites of naturally occurring samples indicates that while reactions governing the Cr and Al solubility and solvus of orthopyroxene give useful estimates of ‘original’ mantle temperatures and pressures, respectively, comparable reactions for clinopyroxene yield estimates that are variably dependent on the transport phase of the sample suites. Temperature and pressure estimates from reactions governing Mg and Fe exchange between silicates and spinel and coexisting silicates are all sensitive to the later transport stage of the samples. |
DS201512-1936 2015 | Mackay, D.A.R., Simandl, G.J. | Niobium and tantalum: geology, markets, and supply chains. | Symposium on critical and strategic materials, British Columbia Geological Survey Paper 2015-3, held Nov. 13-14, pp. 13-22. | Global | Niobium, tantalum |
| Abstract: Until 2014, niobium (Nb) and tantalum (Ta) were on the critical metals list of the European Union (European Commission, 2011; 2014). Both Ta and Nb have high levels of supply chain risk and even temporary disruptions in supply could be difficult to cope with. The Ta market is subject to infl ux of ‘conflict’ columbite-tantalite concentrate, or ’Coltan,’ into the supply chain, displacing production in Australia and Canada. The growing consumer appetite for goods made of ethically sourced or ‘confl ict-free’ minerals and metals has put pressure on manufacturers of components for consumer electronics, such as smart phones, laptop computers, computer hard drives, digital cameras, GPS navigation systems, and airbag triggers to stop using Ta from ‘confl ict’ areas. Other uses of Ta include medical implants, super alloys used in jet turbine and rocket nozzle production, corrosion prevention in chemical and nuclear plants, as a sputtering target, and in optical lenses (Tantalum-Niobium International Study Center, 2015a, b). These applications make Ta economically and strategically important to industrialised countries (European Commission, 2011, 2014; Brown et al., 2012; Papp, 2012). Niobium (Nb) is primarily used in high-strength low-alloy (HSLA) steel used extensively in the oil and gas and automotive industries. Niobium is also a major component in vacuum-grade alloys used in rocket components and other aeronautic applications (Tantalum-Niobium International Study Center, 2015a, c). Demand for Nb is increasing due to greater use of Nb in steel making in China, India, and Russia (Roskill, 2013b; Mackay and Simandl, 2014). Because most primary Nb production is restricted to a single country (Brazil), security of supply is considered at risk (European Commission, 2014). New sources of supply may be developed to diversify geographic location of supply for strategic reasons (Mackay and Simandl, 2014). Herein we summarize the geology, market, and supply chains of Niobium and Tantalum metals. |
DS201512-1937 2015 | Mackay, D.A.R., Simandl, G.J.,Ma, W., Gravel, J., Redfearn, M. | Indicator minerals in exploration for speciality metal deposits: a QEMSCAN approach. | Symposium on critical and strategic materials, British Columbia Geological Survey Paper 2015-3, held Nov. 13-14, pp. 211-218. | Technology | Rare earths |
| Abstract: Quantitative Evaluation of Materials by Scanning electron microscopy (QEMSCAN®) was used to assess carbonatite indicator minerals in fl uvial sediments from the drainage area of the Aley carbonatite, in north-central British Columbia. QEMSCAN® is a viable method for rapid detection and characterization of carbonatite indicator minerals with minimal processing other than dry sieving. Stream sediments from directly above, and up to 11 km downstream, of the carbonatite deposit were selected for this indicator mineral study. The geology of the Aley carbonatite is described by Mäder (1986), Kressal et al. (2010), McLeish (2013), Mackay and Simandl (2014), and Chakhmouradian et al. (2015). Traditional indicator mineral exploration methods use the 0.25-2.0 mm size fraction of unconsolidated sediments (Averill, 2001, 2014; McCurdy, 2006, 2009; McClenaghan, 2011, 2014). Indicator minerals are detectable by QEMSCAN® at particle sizes smaller than those used for hand picking (<0.25 mm). Pre-concentration (typically by shaker table) is used before heavy liquid separation, isodynamic magnetic separation, optical identifi cation using a binocular microscope, and hand picking (McClenaghan, 2011). Following additional sieving, the 0.5-1 and 1-2 mm fractions are hand picked for indicator minerals while the 0.25-0.5 mm fraction is subjected to paramagnetic separation before hand picking (Averill, 2001; McClenaghan, 2011). Hand picking indicator minerals focuses on monomineralic grains, and composite grains may be lost during processing. Composite grains are diffi cult and time consuming to hand pick and characterize using optical and Scanning Electron Microscopy (SEM) methods. A single grain mount can take 6-12 hours to chemically analyse (Layton- Matthews et al., 2014). Detailed sample analysis using the QEMSCAN® Particle Mineral Analysis routine allows for 5-6 samples to be analyzed per day. When only mineral identifi cation and mineral concentrations and counts are required, the use of a Bulk Mineral Analysis routine reduces the analysis time from ~4 hours to ~30 minutes per sample. |
DS201509-0415 2015 | 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. | Mantle | Magmatism |
| 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. |
DS201505-0237 2014 | 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. | Europe | Microdiamonds |
DS201502-0076 2014 | 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, Sweden | Subduction, microdiamond |
DS201512-1938 2015 | Malich, K.N., Khiller, V.V., Badanina, I.Yu., Belousova, E.A. | Results of dating of thorianite and badeleyite from carbonatites of the Guli massif, Russia. | Doklady Earth Sciences, Vol. 464, 2, pp. 1029-1032. | Russia | Carbonatite |
| Abstract: The isotopic -geochronological features of thorianite and baddeleyite from carbonatites of the Guli massif, located within Maimecha -Kotui province in the north of the Siberian Platform, are characterized for the first time. The economic complex platinum-group element (PGE) and gold placer deposits are closely related to the Guli massif. Similar geochronological data for thorianite (250.1 ± 2.9 Ma, MSWD = 0.09, n = 36) and baddeleyite (250.8 ± 1.2 Ma, MSWD = 0.2, n = 6) obtained by two different methods indicate that carbonatites were formed close to the Permian -Triassic boundary and are synchronous with tholeiitic flood basalts of the Siberian Platform. |
DS201501-0018 2015 | Manson, M. | Jacques Cartier's legacy: the Renard diamond project under construction. | PDAC 2015, 1p. Abstract | Canada, Quebec | Deposit - Renard |
DS201507-0323 2016 | Mantovani, M.S.M., Louro, V.H.A., Ribeiro, V.B., Requejo, H.S., dos Santos, R.P.Z. | Geophysical analysis of Catalao 1 alkaline carbonatite complex in Goias, Brazil. | Geophysical Prospecting, Vol. 64, pp. 216-227. | South America, Brazil | Deposit - Catalao |
DS201512-1939 2015 | Mao, M., Simandl, G.J., Spence, J., Marshall, D. | Fluorite trace-element chemistry and its potential as an indicator mineral: evaluation of LA-ICP-MS method. | Symposium on critical and strategic materials, British Columbia Geological Survey Paper 2015-3, held Nov. 13-14, pp. 251-264. | Technology | Rare earths |
| Abstract: Fluorite (CaF2) belongs to the isometric system, with a cubic, face-centred lattice. Fluorite commonly forms cubes or octahedrons, less commonly dodecahedrons and, rarely, tetrahexahedrons, trapezohedrons, trisoctahedrons, hexoctahedrons, and botyroidal forms. Fluorite is transparent to translucent, and has vitreous luster. It occurs in a variety of colours including purple, green, blue, or yellow, however it can also be colourless, and can exhibit colour zoning, (Staebler et al., 2006). Fluorite from many localities is fl uorescent (Verbeek, 2006). Fluorite density varies from 3.0-3.6 g/cm3, depending to a large extent on inclusions and impurities in the crystal lattice (Staebler et al., 2006), and its hardness is 4 on Mohs scale (Berry et al., 1983). Many single fl uorite crystals display sector zoning, refl ecting preferential substitution and incorporation of trace elements along successive crystal surfaces (Bosce and Rakovan, 2001). The Ca2+ ion in the fl uorite crystal structure can be substituted by Li+, Na+, K+, Mg2+, Mn2+, Fe2+,3+, Zn2+, Sr2+, Y3+, Zr4+, Ba2+, lanthanides ions, Pb2+, Th4+, and U4+ ions (Bailey et al., 1974; Bill and Calas, 1978, Gagnon et al., 2003; Schwinn and Markl, 2005; Xu et al., 2012; Deng et al., 2014). Concentrations of these impurities do not exceed 1% (Deer, 1965) except in yttrofl uorite (Ca,Y)F2-2.33 and cerfl uorite (Ca,Ce)F2-2.33 (Sverdrup, 1968). Fluorite occurs in a variety of rocks, as an accessory and as a gangue mineral in many metalliferous deposits and, in exceptional cases, as the main ore constituent of economic deposits (Simandl, 2009). Good examples of fl uorite mines are Las Cuevas, Encantada-Buenavista (Mexico); St. Lawrence pluton-related veins and the Rock Candy Mine (Canada); El Hamman veins (Morocco) and LeBurc Montroc -Le Moulinal and Trebas deposits (France) as documented by Ruiz et al. (1980), Grogan and Montgomery (1975), González-Partida et al. (2003), Munoz et al. (2005), and Fulton III and Miller (2006). Fluorite also commonly occurs adjacent to or within carbonatites and alkaline complexes (Kogut et al., 1998; Hagni,1999; Alvin et al., 2004; Xu et al., 2004; Salvi and Williams-Jones, 2006); Mississippi Valley-type (MVT) Pb- Zn-F-Ba deposits; F-Ba-(Pb-Zn) veins (Grogan and Bradbury, 1967 and 1968; Baxter et al., 1973; Kesler et al., 1989; Cardellach et al., 2002; Levresse et al., 2006); hydrothermal Fe (±Au, ±Cu) and rare earth element (REE) deposits (Borrok et al., 1998; Andrade et al., 1999; Fourie, 2000); precious metal concentrations (Hill et al., 2000); fl uorite/metal-bearing skarns (Lu et al., 2003); Sn-polymetallic greissen-type deposits (Bettencourt et al., 2005); and zeolitic rocks and uranium deposits (Sheppard and Mumpton, 1984; Cunningham et al., 1998; Min et al., 2005). Ore deposit studies that document the trace element distribution in fl uorite are provided by Möller et al. (1976), Bau et al. (2003), Gagnon et al. (2003), Schwinn and Markl (2005), and Deng et al. (2014). The benchmark paper by Möller et al. (1976) identifi ed variations in the chemical composition of fl uorites according their origin (sedimentary, hydrothermal, or pegmatitic). Recently, Makin et al. (2014) compiled trace-element compositions of fl uorite from MVT, fl uorite-barite veins, peralkaline-related, and carbonatite-related deposits. They showed that fl uorite from MVT and carbonatite deposits can be distinguished through trace element concentrations, and that the REE concentration of fl uorite from veins is largely independent of the composition of the host rock. Based on the physical and chemical properties of fl uorite, its association with a variety of deposit types, and previous studies, it is possible that fl uorite can be used as a proximal indicator mineral to explore for a variety of deposit types. Unfortunately, the compilation by Makin et al. (2014) contained chemical analyses performed at different laboratories using different analytical techniques (including laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS), electron microprobe, neutron activation, and ICP-MS), and precision and accuracy varied accordingly. As an orientation survey, herein we present data from fi ve deposits, with two samples from the Rock Candy deposit (British Columbia), and one sample from each of Kootenay Florence (British Columbia), Eaglet (British Columbia), Eldor (Quebec), and Hastie quarry (Illinois) deposits (Table 1). The main objectives of this study are to: 1) assess variations in chemical composition of fl uorite in the samples and deposit types; 2) evaluate relations between analyses made using laser ablation-inductively coupled plasma mass spectrometry on individual grains [LA-ICP-MS(IG)], and those made using laser ablation-inductively coupled plasma mass spectrometry on fused beads [LA-ICP-MS(FB)] and X-ray fl uorescence (XRF); 3) test the use of stoichiometric Ca content as an internal fl uorite standard, such has been done by Gagnon et al. (2003) and Schwinn and Markl, (2005); 4) select the elements that are commonly present in concentrations above the lower limit of detection of LA-ICP-MS and available for constructing discrimination diagrams; 5) consider if our results agree with the preliminary discrimination diagrams of Makin et al. (2014). |
DC201507-1572 2015 | Marange Resources PVT Ltd. | Marange Resources is now technically insolvent with the companies liabilities exceeding assets by a staggering US$74,7 million. | The Independent ( Zimbabwe), June 22, 1p. | Africa, Zimbabwe | News item - Marange Resources |
DC201504-1573 2015 | Margaret Lake Diamonds Inc. | Announces non-brokered private placement. ( prospect near Gahcho Kue). | Margaret Lake Diamonds Inc., Mar. 19, 1p. | Canada, Northwest Territories | News item - press release |
DC201505-1574 2015 | Margaret Lake Diamonds Inc. | Closes non-brokered private placement $ 100,620. | Margaret Lake Diamonds Inc., Mar. 27, 1p. | Canada, Northwest Territories | News item - press release |
DC201505-1575 2015 | Margaret Lake Diamonds Inc. | High priority drill targets defined on Margaret Lake property. | Margaret Lake Diamonds Inc., Apr. 20, 1p. | Canada, Northwest Territories | News item - press release |
DC201508-1576 2015 | Margaret Lake Diamonds Inc. | Margaret Lake Diamonds Inc. acquisition of 100% interest in Margaret Lake property & land use permit. | Margaret Lake Diamonds Inc., July 13, 1p. | Canada, Northwest Territories | News item - press release |
DS201512-1940 2015 | 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 10.024 | Africa, West Africa | Reguibat 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. |
DS201510-1784 2015 | Markwitz, V., Hein, K.A.A., Miller, J. | Compilation of West African mineral deposits: spatial distribution and mineral endowment. ( mentions diamonds) | Precambrian Research, in press available, 21p. | Africa, Mali, Mauritania, Senegal, Burkina Faso, Ghana, Ivory Coast | Metallogeny |
| Abstract: The West African Craton is highly endowed in minerals, and their spatial and temporal distribution varies from single to multi-phase mineralization events. They are broadly related to three major tectono-metallogenic elements and formed during distinct mineral epochs: (1) In both Archean Shields (Kénéma-Man and Reguibat) and Paleoproterozoic domains (Baoulé-Mossi, Eglab). These are characterized by giant iron ore deposits that formed between ca. 2.5-2.3 Ga, nearly all gold, porphyry copper, lead-zinc and sedimentary manganese ore that developed between 2.2 and 2.1 Ga, and primary diamonds that formed between two intervals at ca. 2.2-2.0 Ga and in the Mesozoic. (2) Across Pan-African and Variscan belts. These are distinguished by major Precambrian IOCG's, copper-gold that formed at ca. 2.1 Ga and approximately 680 Ma, and Neoproterozoic sedimentary iron ore and phosphate deposits. (3) Within intracratonic and coastal basins. These include the development of Cenozoic lateritic bauxites over Mesozoic dolerites, Tertiary/Quaternary mineral sands deposits, oolitic iron ore and sedimentary phosphate deposits. Geological, spatial and temporal correlations using the multi-commodity West African Mineral Deposit Database highlight that gold and non-gold commodities formed in multiple phases. This commenced in the Liberian Orogeny (2.9-2.8 Ga) with the enrichment of iron ore, nickel sulphides, diamonds and gold in the earth's crust. The pre-Eburnean or Tangaean-EoEburnean-Eburnean I Event yielded gold, and the major Eburnean Orogeny yielded gold, iron ore, manganese, diamonds, magmatic nickel sulphides, copper-gold, lead-zinc, and REE minerals. Throughout the Pan-African event sedimentary manganese deposits, lead-zinc, REE minerals, sedimentary phosphates, and again gold were formed. Primary diamonds and magmatic nickel sulphides are related to the break-up of Gondwana, followed by an intense lateritic weathering period that formed bauxite deposits along the craton margin. |
DS201505-0255 2015 | Marquardt, H., Miyagi, L. | Slab stagnation in the shallow mantle linked to an increase in mantle viscosity. | Nature Geoscience, Vol. 8, pp. 311-314. | Mantle | Subduction |
DS201507-0324 2015 | Marques de Morais, R. | Blood diamonds: torture and corruption in Angola. IN ENGLISH publ originally in Portugal in 2011. | Diamonds.net, English translation 156p. Pdf available | Africa, Angola | Book |
DS201502-0077 2014 | Martens, U., Restrepo, J.J., Ordonez-Carmona, O., Correa-Martinez, A.M. | The Tahami and Anaconda terranes of the Colombian Andes: missing links between South American and Mexican Gondwana margins. | Journal of Geology, Vol. 122, Sept. pp. 507-530. | South America, Mexico | Tectonics |
DS201510-1785 2015 | Martin, A.P., Price, R.C., Cooper, A.F., McCammon, C.A. | Petrogenesis of the rifted southern Victoria Land lithospheric mantle, Antarctica, inferred from petrography, geochemistry, thermobarometry and oxybarometry of peridotite and pyroxenite xenoliths from the Mount Morning eruptive centre. | Journal of Petrology, Vol. 56, 1, pp. 193-226. | Antarctica | Melting, subduction |
| Abstract: The lithospheric mantle beneath West Antarctica has been characterized using petrology, whole-rock and mineral major element geochemistry, whole-rock trace element chemistry and Mössbauer spectroscopy data obtained on a suite of peridotite (lherzolite and harzburgite) and pyroxenite xenoliths from the Mount Morning eruptive centre, Southern Victoria Land. The timing of pyroxenite formation in Victoria Land overlaps with subduction of the Palaeo-Pacific plate beneath the Gondwana margin and pyroxenite is likely to have formed when fluids derived from, or modified by, melting of the subducting, eclogitic, oceanic crustal plate percolated through peridotite of the lithospheric mantle. Subsequent melting of lithospheric pyroxenite veins similar to those represented in the Mount Morning xenolith suite has contributed to the enriched trace element (and isotope) signatures seen in Cenozoic volcanic rocks from Mount Morning, elsewhere in Victoria Land and Zealandia. In general, the harzburgite xenoliths reflect between 20 and 30% melt depletion. Their depleted element budgets are consistent with Archaean cratonization ages and they have mantle-normalized trace element patterns comparable with typical subcontinental lithospheric mantle. The spinel lherzolite mineral data suggest a similar amount of depletion to that recorded in the harzburgites (20-30%), whereas plagioclase lherzolite mineral data suggest <15% melt depletion. The lherzolite (spinel and plagioclase) xenolith whole-rocks have compositions indicating <20% melt depletion, consistent with Proterozoic to Phanerozoic cratonization ages, and have mantle-normalized trace element patterns comparable with typical depleted mid-ocean ridge mantle. All peridotite xenoliths have undergone a number of melt-rock reaction events. Melting took place mainly in the spinel peridotite stability field, but one plagioclase peridotite group containing high-sodium clinopyroxenes is best modelled by melting in the garnet field. Median oxygen fugacity estimates based on Mössbauer spectroscopy measurements of spinel and pyroxene for spinel-facies conditions in the rifted Antarctic lithosphere are -0·6 ?log fO2 at Mount Morning and –1·0 ± 0·1 (1?) ?log fO2 for all of Victoria Land, relative to the fayalite-magnetite-quartz buffer. These values are in good agreement with a calculated global median value of -0·9 ± 0·1 (1?) ?log fO2 for mantle spinel-facies rocks from continental rift systems. |
DM201502-0896 2015 | Marus, Y. | The Argyle diamond phenomenon. Analysis of all Argyle tenders. | leibish.com, Jan. 25, 11p. | Australia | News item - Argyle |
DS201504-0207 2014 | Masselot, M.J. | Diamants noirs polycrusallns rencontres en joaillerie. | Thesis, 'Diplome D'Universite de Gemmologie devant l'Universite de Nantes U.F.R. des Sciemces et des Techniques, April , 55p. Available | Technology | Black diamond |
DS201510-1786 2015 | Massuyeau, M., Gardes, E., Morizet, Y., Gaillard, F. | A model for the activity of silica along the carbonatite-kimberlite-mellilitite-basanite melt compositional joint. | Chemical Geology, Vol. 418, pp. 206-216. | Technology | Kimberlite |
| Abstract: Carbon dioxide and water, being present in the Earth's mantle at concentration levels of tens to hundreds of ppm, greatly lower the peridotite solidus temperature and drastically modify the composition of produced melts. The presence of CO2 produces silica-poor, carbonate-rich liquids at the onset of melting, and these liquids shift toward silica rich compositions as the degree of melting increases. Numerous geochemical observations and experimental studies have revealed the complexity of the transition between carbonate-rich and silicate-rich melts. It is characterized by a strongly non-linear evolution and, under specific conditions, by immiscibility. To better constrain this transition, we have used the thermodynamic activity of silica as a probe of the mixing properties between molten carbonate and molten silicate. The activity of silica (aSiO2(l))aSiO2l was calculated for a large number of experimental liquids from two equilibria: olivine-orthopyroxene-melt and immiscible silicate-rich melt-carbonate-rich melt (491 data points ranging from 1 to 14 GPa and 1090 to 1800 °C). We modelled aSiO2(l)aSiO2l during incipient melting of the peridotite in presence of CO2 with a generalized Margules function. Our model reproduces well the silica activity-composition relationships of the experimental database, and can be used to predict the silica content of the melts coexisting with olivine and orthopyroxene. We show that water content and Ca/Mg ratio in the melts have an important influence on the aSiO2(l)aSiO2l. In contrast to a recent empirical model (Dasgupta et al., 2013), the analysis of the experimental database reveals that the transition from carbonate to silicate melt with decreasing depth should occur abruptly in oceanic mantle. Our model predicts that carbonatitic melts with ~ 5 wt.% SiO2 can be stabilized from ~ 150 km depth, at the onset of incipient melting by "redox melting", up to ~ 75 km, above which the liquid evolves abruptly to a carbonated silicate composition (> ~ 25 wt.% SiO2). In the cratonic mantle lithosphere, our model predicts that carbonatitic melts are prevailing up to shallow depth, and conflicts the recent model (Russell et al., 2012) of CO2-saturation triggered by orthopyroxene assimilation during kimberlite ascent. |
DS201501-0019 2015 | Masy, J., Niu, F., Levander, A., Schmitz, M. | Lithospheric expression of cenozoic subduction, mesozoic rifting and the Precambrian shield in Venezuela. | Earth and Planetary Science Letters, Vol. 410, pp. 12-24. | South America, Venezuela | Subduction |
DS201512-1941 2015 | Mather, A.E., Mills, S., Stokes, M., Fyfe, R. | Ten years on: Google Earth offer the geoscience community? | Geology Today, Vol. 31, 6, pp. 216-221. | Technology | Google Earth |
| Abstract: Google Earth has been part of most geoscientists' computer (and mobile) desktops for a decade, and this year Google Earth Professional has become freely available to all with a universal license key. Many users are still, however, not aware of the full potential that it can offer across a range of teaching and research areas in the geosciences. Here a pragmatic look is taken at some of the current key uses in terms of resources and applications and how they can help in research and training educational roles in the geosciences. |
DS201512-1942 1989 | McCandless, T.E. | Microdiamonds from the Sloan 1 and 2 kimberlites, Colorado, USA. | 28th International Geological Congress, Washington DC, Workshop on Diamonds, extended abstracts, pp. 44-46. | United States, Colorado Plateau | Microdiamonds |
DS201512-1943 1999 | McCandless, T.E., Letendre, J., Eastoe, C.J. | The morphology and carbon isotope chemistry of microdiamonds from the Dachine Diamondiferous body, French Guiana. | Proceedings of rhe 7th International Kimberlite Conference, Vol. 2, pp. 550-556. | South America, French Guiana | Microdiamonds |
DS201512-1944 1994 | McCandless, T.E., Waldman, M.A., Gurney, J.J. | Macro- and microdiamonds from Arkansas lamproites: morphology, inclusions and isotope geochemistry. | Proceedings of the 5th. International Kimberlite Conference, Vol. 2, pp. 78-97. | United States, Arkansas | Microdiamonds |
| Abstract: The first report of diamond in igneous rock in the United States originated at Prairie Creek, Arkansas. We have examined the morphological, carbon isotope, and inclusion characteristics of diamonds from Prairie Creek, and from the Twin Knobs # 1, #2, Black Lick, and American lamproites. White is the most common macrodiamond color at Prairie Creek (62% of total), with 20% brown and 16% yellow. This contrasts with Australian lamproites where brown predominates, and with other North American localities such as the Sloan, Colorado kimberlites where yellow is rare. Lamination lines indicate ductile deformation at mantle conditions. The macrodiamonds are very resorbed; 82% are equiform or distorted tetrahexahedroida and none are octahedra. Low relief surfaces indicate prolonged and/or intense resorption. Microdiamonds differ dramatically, with octahedra and fragn~ents common and tetrahexahedroida abscnL Serrate laminae, knob-like asperities, pointed plates, ribbing, and non-uniform resorption are the most common surface features. Diamonds from the Twin Knobs # 1 lamproite are similar to microdiamonds with respect to size and surface features. Magnetite and olivine (F093) are the only primary inclusions foqnd in the diamonds, although inclusions of peridotitic and eclogitic parageneses have been reported in previous studies. Carbon isotope B13c values for Prairie Creek macrodiamonds peak at-3.0 to -6.2 %o (ave. -4.7 %o for 19 stones) and -10.3 to -10.6 %o (ave. -10.5 %o for 2 stones). The diamonds with magnetite and olivine inclusions have B13c values of -5.1 %o and -4.0 %o respectively. Microdiamonds from Prairie Creek, Twin Knobs #2, American, and Black Lick are similar to Prairie Creek macrodiamonds ( -0.5 to -7 .8; ave. -4.1 %o for 8 stones). A Prairie Creek and a Black Lick microdiamond have B13c values of -26.1 and -25.2%orespectively, and the latter exhibits non-uniform resorption. Lamination lines on macrodiamonds and xenocrystic surface features on microdiamonds imply that both are xenocrysts in lamproite. Carbon isotopes are characteristic of a peridotitic or primordial carbon reservoir. Two 13cdepleted microdiamonds may be from a subducted carbon source. In comparison to macrodiamond populations from most kimberlites, Prairie Creek macrodiamonds are intensely resorbed, and lamproite may be more corrosive than kimberlite \\ ith respect to diamond resorption. Microdiamonds were probably encapsulated in xenolith material ani.! esca•,)ed resorption. The differences in size and color of Prairie Creek macrodiamonds relative to Sloan kimberlitic diamonds are genetic, and may be related to their formation in lithosphere of differing age and tectonic history. |
DS201504-0208 2015 | McGuiness, L.P., Jelezko, F. | Look but don't touch the metals. | Science, Vol. 347, 6226, pp. 1073-1074 Mar. 6. | Technology | Metal conductivity, atomic defects in diamond |
DS201509-0416 2015 | McKenzie, D., Daly, M.C., Priestley, K. | The lithospheric structure of Pangea. | Geology, Vol. 43, 9, pp. 783-786. | Mantle | Pangea |
| Abstract: Lithospheric thickness of continents, obtained from Rayleigh wave tomography, is used to make maps of the lithospheric thickness of Pangea by reconstructing the continental arrangement in the Permian. This approach assumes that lithosphere moves with the overlying continents, and therefore that the arrangement of both can be obtained using the poles of rotation obtained from magnetic anomalies and fracture zones. The resulting reconstruction shows that a contiguous arc of thick lithosphere underlay most of eastern Pangea. Beneath the western convex side of this arc, there is a wide belt of thinner lithosphere underlying what is believed to have been the active margin of Pangea, here named the Pangeides. On the inner side of this arc is another large area of thin lithosphere beneath the Pan-African belts of North Africa and Arabia. The arc of thick lithosphere is crossed by bands of slightly thinner lithosphere that lie beneath the Pan-African and Brasiliano mobile belts of South America, Africa, India, Madagascar, and Antarctica. This geometry suggests that lithospheric thickness has an important influence on continental deformation and accretion. |
DS201512-1945 2015 | McKillop, R.J., Sacco, D.A. | Using property scale surficial geology mapping to refine kimberlite indicator mineral dispersal patterns at the Redemption project, NWT. | 43rd Annual Yellowknife Geoscience Forum Abstracts, abstract p. 64. | Canada, Northwest Territories | Deposit - Redemption |
| Abstract: Surficial sediment (e.g., till) sampling is an effective tool for mineral exploration in the glaciated landscapes of Canada. Dispersal patterns identified through surficial sampling are studied and used to identify their smaller, mineralized bedrock sources. Data compiled from multiple sampling programs, such as those included in the Kimberlite Indicator and Diamond Database (KIDD), can produce misleading dispersal patterns due to variability in sampling and analysis protocols. The accurate delineation of dispersal patterns requires an understanding of the genesis, comparability and distribution of sediment samples on which the dispersal patterns are based. Using an example from a recent study of the South Coppermine indicator mineral train on the Redemption Project, we demonstrate a method for reducing the variability in the data set that utilizes property-scale surficial geology mapping to systematically filter and normalize the data. The surficial geology mapping identified the nature and distribution of sediments, as well as specific till units that have been reworked to differing degrees by a combination of glacial meltwater, modern drainage and periglacial processes, which can affect the concentration of kimberlite indicator minerals (KIMs). A derivative map depicting till sampling suitability based on basal till potential and the level of reworking was used to classify and group samples into subset populations, from which less-favourable samples were filtered. KIM counts in the remaining sample data were then leveled (normalized) according to the thickness of the sampled till unit to reduce the bias produced by higher anomalies common to thin till units. The filtered and normalized data produced a sharper, more accurate KIM dispersal pattern and a new basis for interpreting possible provenance envelopes, from which lower-risk exploration targets can be identified. |
DS201512-1946 2015 | McKillop, R.J., Turner, D.G., Sacco, D.A. | Quaternary geology interpretation for the Slave surficial materials and permafrost study. | 43rd Annual Yellowknife Geoscience Forum Abstracts, abstract p. 65. | Canada, Northwest Territories | Geomorphology |
| Abstract: The Northwest Territories Geological Survey recently funded a strategic overburden drilling program in the Lac de Gras (NTS 076D) and Alymer Lake (NTS 076C) map areas of the Slave Province, Northwest Territories. This program was designed to help stimulate mineral exploration, and to collect permafrost and geotechnical data required for future infrastructure development. To provide guidance for the drill program and a basis for interpreting the results, we compiled, analyzed and interpreted an unprecedented collection of privately-collected and public data. The data set included extensive LiDAR-derived hillshade models; regional surficial and bedrock geology mapping; and mineralogical, geochemical, grain size and sample description data from surface sediment (till) samples. Our systematic mapping of the LiDAR coverage area resulted in the identification of 649 linear features, including eskers, meltwater channels, moraines, paleo-shorelines and streamlined bedforms, which strengthened understanding of local ice flow histories and patterns of deglaciation. Based on a comprehensive review and re-evaluation of the data, we identified six important trends: (1) samples collected from till blankets have lower indicator mineral counts than those collected from till veneers and thick, hummocky till deposits; (2) indicator mineral counts from glaciofluvial sediments were lower and show more subtle anomalies than those from till; (3) the =0.5 mm size-fraction in the mineralogy data set has ~25-40% higher indicator mineral counts than the >0.5 mm size-fraction; (4) when comparing the analytical results of different size fractions, Cr and La concentrations are higher in the clay-sized fraction, while Ba concentrations are higher in the silt- and clay-sized fraction; (5) anomalous Au concentrations in the northern portion of the study area likely represent a lithological change and subsequent glacial dispersion, rather than significant mineralization; and (6) local variations in pyrope and Cr-diopside counts in the study area may affect interpretations of kimberlite indicator mineral dispersal plumes. We also delineated 60 areas of interest that present unique research opportunities, or represent important data gaps that compromise the understanding of glacial history, mineral dispersal and permafrost conditions within the region. |
DS201512-1947 2015 | McLachlan, C. | Diavik mine operational update. | 43rd Annual Yellowknife Geoscience Forum Abstracts, abstract p. 66. | Canada, Northwest Territories | Deposit - Diavik |
| Abstract: Since 2003 Diavik Diamond Mines Inc. has been mining diamonds from kimberlite pipes located below the waters of Lac de Gras. Diavik produces 6-7 million carats annually and in 2012 Diavik transitioned to a fully underground mine. Diavik’s 9.2 megawatt award winning wind farm has confirmed Diavik as a leader in cold climate, off grid renewable energy. Diavik recently began construction on its A21 project, which will bring its fourth kimberlite pipe into production in 2018. This presentation will provide an operational update on the amazing Diavik operation. |
DS201512-1948 2015 | McLeod, W., Coyne, P. | Challenges and triumps on the Inuvik to Tuktoyaktuk highway. | 43rd Annual Yellowknife Geoscience Forum Abstracts, abstract p. 66. | Canada, Northwest Territories | Ice road |
| Abstract: The Inuvik to Tuktoyaktuk Highway (ITH) has been an idea for over 50 years. It was only in the past decade that the project gained traction towards becoming a reality. Once constructed, the ITH will be an all-weather link between these two communities in the Mackenzie Delta region of the Northwest Territories. Working collaboratively with our aboriginal partnership company KAVIK-STANTEC in Inuvik, Stantec has completed a variety of tasks ranging from baseline environmental assessment (wildlife, vegetation, and terrain), regulatory support and civil engineering design services. Crews hit the ground in the winter of 2013/2014 and the project is now entering its third and final winter construction season. The project team (designers, constructors and the Owner) contended with several challenges in bringing the project to fruition. Some of these included: • Fast track schedule • Weather constraints • Data refinements • Climate change considerations • Large complexity of the project (requiring collaborative approach) When completed, the ITH will span over 140 km and provide a vital access route for industry and the public. Stantec will discuss the challenges and triumphs in working on this diverse project working in this remote landscape. |
DS201510-1787 2015 | McManus, C.E., Dowe, J., McMillan, N.J. | Determination of diamond provenance is possible with multivariate analysis of LIBS spectra. ( Laser Induced Breakdown Spectroscopy) | GSA Annual Meeting, Paper 300-4, 1p. Abstract only Booth | Technology | Spectroscopy |
| Abstract: The ability to accurately determine the provenance of gem diamonds impacts economic, political, and national security arenas. Currently, provenance determinations rely on: 1) gemological and mineralogical features of stones, such as spectroscopic measurements, geochemistry, and inclusions, and 2) certification and tracking of individual stones through the Kimberly Process Certificate Scheme. Unfortunately, during cutting and polishing, many gemological features are obliterated and tracking individual stones through the chain of custody can be difficult. This study resulted in a highly successful method for determining provenance of cut diamonds from information in the stone itself.
A set of 30 cut diamonds from each of ten controlled localities and one set of 30 synthetic diamonds were analyzed by Laser-Induced Breakdown Spectroscopy (LIBS). The sample set (330 total diamonds) includes both kimberlite and placer diamonds from five countries and five different cratons. LIBS acquires the atomic emission spectra released from a material during laser ablation. The spectra contain information from nearly every element in the periodic table, and thus are unique chemical, or quantagenetic, signatures of the material. Spectra were analyzed using a Bayesian statistical method that compares groups of samples defined by the reported locations of the stones to clusters of samples defined by spectral similarity. Ideally, each spectral cluster coincides with a group of stones. The spectrum of each sample is compared to a set of reference spectra from each group to determine the probable provenance of the sample. The correlation between groups and clusters was excellent, with average accuracy of 98%, suggesting that diamonds from each location are spectrally similar to each other and distinct from those from other locations. This is true even for diamonds from kimberlites in close proximity to each other. Synthetic diamonds are easily distinguished from natural diamonds (100% success). Some groups of diamonds in the study are more heterogeneous than others. For instance, a placer group has five recognizable spectrally-defined sub-clusters. This work demonstrates that diamond provenance can be determined at a high level of confidence on individual cut gemstones. |
DS201512-1949 2015 | McManus, C.E., Dowe, J., McMillan, N.J. | Determination of diamond provenance is possible with multivariate analysis of LIBS spectra. | Materialytics.com, Available from c.McManus @materialytics.com 1 poster ( 4 parts) | Global | Laser Induced Breakdown Spectroscopy |
| Abstract: The ability to accurately determine the provenance of gem diamonds impacts economic, political, and national security arenas. Currently, provenance determinations rely on: 1) gemological and mineralogical features of stones, such as spectroscopic measurements, geochemistry, and inclusions, and 2) certification and tracking of individual stones through the Kimberly Process Certificate Scheme. Unfortunately, during cutting and polishing, many gemological features are obliterated and tracking individual stones through the chain of custody can be difficult. This study resulted in a highly successful method for determining provenance of cut diamonds from information in the stone itself. A set of 30 cut diamonds from each of ten controlled localities and one set of 30 synthetic diamonds were analyzed by Laser-Induced Breakdown Spectroscopy (LIBS). The sample set (330 total diamonds) includes both kimberlite and placer diamonds from five countries and five different cratons. LIBS acquires the atomic emission spectra released from a material during laser ablation. The spectra contain information from nearly every element in the periodic table, and thus are unique chemical, or quantagenetic, signatures of the material. Spectra were analyzed using a Bayesian statistical method that compares groups of samples defined by the reported locations of the stones to clusters of samples defined by spectral similarity. Ideally, each spectral cluster coincides with a group of stones. The spectrum of each sample is compared to a set of reference spectra from each group to determine the probable provenance of the sample. The correlation between groups and clusters was excellent, with average accuracy of 98%, suggesting that diamonds from each location are spectrally similar to each other and distinct from those from other locations. This is true even for diamonds from kimberlites in close proximity to each other. Synthetic diamonds are easily distinguished from natural diamonds (100% success). Some groups of diamonds in the study are more heterogeneous than others. For instance, a placer group has five recognizable spectrally-defined sub-clusters. This work demonstrates that diamond provenance can be determined at a high level of confidence on individual cut gemstones. |
DC201503-1577 2015 | MDN Inc. | MDN acquires 20 blocks of high grade niobium claims in Ontario. Prairie Lake ( alkaline) | MDN Inc., Feb. 24, 1p. | Canada, Ontario | News item - press release |
DC201505-1578 2015 | MDN inc. | MDN acquires 20 blocks of high grade niobium claims in Ontario. ( Prairie Lake carbonatite) | MDN Inc., Feb. 24, 1p. | Canada, Ontario | News item - press release |
DC201506-1579 2015 | MDN Inc. | Prospecting work begins on Prairie Lake. | MDN Inc., May 27, 1p. | Canada, Ontario | News item - press release |
DS201511-1863 2015 | Meissner, R., Ramasar, V. | Governance and politics in the upper Limpopo River basin, South Africa. | Geojournal, Vol. 80, 5, pp. 689-709. | Africa, South Africa | Mentions Venetia |
| Abstract: Everyday international political economy (EIPE) offers an opportunity to rethink the role of individuals and citizenry in shaping governance of natural resources. In South Africa, significant progress has been made by government in re-shaping water governance since the end of apartheid in the early 1990s. The role of government in water governance and water politics has thus been emphasised to a large degree. This study looks at historical material to assess the role that water politics and EIPE has played in shaping the use and management of water resources in the country. Case studies are analysed of two quaternary catchments, A63E and A71L in the Limpopo River Basin, to show how everyday actions by different actors has shaped the current waterscape in the basin. Four events, namely, the politics of the Middle Iron Age State at Mapungubwe; the development of the Mapungubwe National Park and World Heritage Site; the management of water for the De Beers Venetia Diamond Mine; and the establishment of the Coal of Africa Limited colliery are discussed in terms of the agential power at play during each event. The conclusions of the study are that EIPE and reflexive agential power are important factors in water governance that can sometimes be ignored through neoliberal institutionalism. In the current and future governance of water in South Africa they can offer an alternative view of the role and importance of actors and pathways for development. |
DS201503-0160 2015 | Menezes Filho, L.A.D., Atencio, D., Andrade, M.B., Downs, R.T., Chaves, M.L.S.C., Romano, A.W., Scholz, R., Persiano, A.I.C. | Pauloabibite, trigonal NaNbO3, isostructural with ilmenite, from the Jacupiranga carbonatite, Cajati, Sao Paulo, Brazil. | American Mineralogist, Vol. 100, pp. 442-446. | South America, Brazil | Carbonatite |
DC201502-1580 2015 | Merlin Diamonds Limited | Blumont Group drops its takeover bid. | Merlin Diamonds, Jan. 16, 1/2p. | Australia | News item - press release |
DC201504-1581 2015 | Merlin Diamonds Limited | $4.5 million R & D refund brings Merlin Diamond mine closer to production. | Merlin Diamonds Limited, Mar. 19, 1p. | Australia | News item - press release |
DC201506-1582 2015 | Merlin Diamonds Limited | Merlin mine - mining operations and exploration update. | Merlin Diamonds Limited, Apr. 30, 2p. | Australia | News item - press release |
DC201509-1583 2015 | Merlin Diamonds Limited | Merlin diamond project .. Mechanical clamshell grab mining ( barge). | Merlin Diamonds Limited, July 30, 14p. | Australia | News item - press release |
DC201512-2443 2015 | Merlin Diamonds Limited | Merlin mine - final design of barge and gantry mining. | Merlin Diamonds Limited, Oct. 30, 1p. Highlights | Australia | News item - press release |
DC201505-1584 2015 | Metalex Ventures Ltd. | U2 kimberlite bulk sample permitting complete. | Metalex Ventures Ltd., Apr. 21, 2p. | Canada, Ontario, Attawapiskat | News item - press release |
DC201504-1588 2015 | Meteoric Resources NL | Quarterly report: Webb project. | Meteoric Resources NL., Mar. 12, 1p. | Australia | News item - press release |
DC201505-1585 2015 | Meteoric Resources NL | Webb exploration update 51 kimberlite bodies… Type 1 ( no microdiamonds determined as yet) | Meteoric Resources NL, Mar. 26, 4p. | Australia | News item - press release |
DC201506-1586 2015 | Meteoric Resources NL | Diamond anomaly reinforced at Webb. Kimberlite cluster | Meteoric Resources NL, Apr. 23, 11p. | Australia | News item - press release |
DC201509-1587 2015 | Meteoric Resources NL | Webb project update Quarterly report. | Meteoric Resources NL, July 30, 9p. | Australia | News item - press release |
DC201512-2444 2015 | Meteoric Resources NL | Webb diamond joint venture update. Microdiamond samples | Meteoric Resources nl, Oct. 28, 1p. Highlights | Australia | News item - press release |
DS201510-1788 2015 | Michelfelder, G.S., Karfunkel, J., Fernandes, A.F., Sgarbi, N.C., Hoover, D.B., Krambrock, K., Walde, D. | Surface source of Coromandel diamonds ( Minas Gerais State), Brazil) and their possible origin from the Serra Negra/Salitre supervolcano. | GSA Annual Meeting, Paper 300-1, 1p. Abstract only Booth | South America, Brazil, Minas Gerais | Deposit - Coromandel |
| Abstract: The origin of diamonds in the Coromandel area has been an enigma for many years, in spite of high investment in conventional and high tech prospecting methods by major mining companies for over half a century. The authors review the history, and then discuss the two principal hypotheses to explain the source of these alluvial diamonds. After mapping the headwater region of one of the richest alluvial diamond rivers, the Santo Antônio do Bonito River, they reject both principal hypotheses and conclude that the surficial source can be only the Upper Cretaceous Capacete Formation, composed of pyroclastics and epiclastics. Based on geophysical data from the literature, combined with field observations the authors suggest that the largest alkaline complex, situated within the diamond producing area, the Serra Negra/Salitre Complex has been the primary source for those pyroclastics of the Capacete Formation and the diamonds. The plugs of this complex are 15-30 times deeper than average kimberlites and other alkaline complexes in the region, and its excess of volume of the intrusive is three orders of magnitude larger than a typical kimberlite. With an intrusive volume of over 1000 km3 the complex is suggested to be a possible supervolcano. This explains the vast areal distribution of the pyroclastics and diamonds. This new hypothesis has advantages and disadvantages, some of them discussed in the paper and leading to the conclusion that further research is needed. |
DS201502-0078 2014 | Midende, G., Boulvais, P., Tack, L., Melcher, F., Gerdes, A., Dewaele, S., Demaiffe, D., Decree, S. | Petrography, geochemistry and U-Pb zircon age of the Matongo carbonatite Massif ( Burundi): implication for the Neoproterozoic geodynamic evolution of Central Africa. | Journal of African Earth Sciences, Vol. 100, pp. 656-674. | Africa, Burundi | Carbonatite |
DS201507-0325 2015 | Mikhailova, J.A., Kalashnikov, A.O., Sokharev, V.A., Pakhomovsky, Y.A., Konopleva, N.G., Yakovenchuk, V.N., Bazai, A.V., Goryainov, P.M., Ivanyuk, G.Yu. | 3D mineralogical mapping of the Kovdor phoscorite-carbonatite complex, Russia. | Mineralium Deposita, In press available. 19p. | Russia | Carbonatite |
DS201502-0079 2015 | Mikhno, A.O., Korsakov, A.V. | Carbonate, silicate, and sulfide melts: heterogeneity of the UHP mineral forming media in calc-silicate rocks from the Kokchetav massif. | Russian Geology and Geophysics, Vol. 56, 1-2, pp. 81-99. | Russia, Kazakhstan | Kokchetav massif |
DS201502-0080 2014 | Milan, R. | The mineralogical system: 2 D projections and their potential in mineral identification. | European Journal of Mineralogy, Vol. 26, 6, pp. 703-710. | Technology | Mineralogy |
DS201507-0326 2015 | Milani, S., Nestola, F., Alvaro, M., Pasqual, D., Mazzucchelli, M.L., Domeneghetti, M.C., Geiger, C.A. | Diamond -garnet geobarometry: the role of garnet compressibility and expansivity. | Lithos, Vol. 227, pp. 140-147. | Technology | Geobarometry |
DS201501-0020 2014 | Mildragovic, D., Francis, D., Weis, D., Constantin, M. | Neoarchean ( c.2.7Ga) plutons of the Ungava craton, Quebec, Canada: parental magma compositions and implications for Fe-rich mantle source regions. | Journal of Petrology, Vol. 55, 12, pp. 2481-2512. | Canada, Quebec | Melting |
DS201511-1864 2015 | Milidragovic, D., Francis, D. | Ca. 2.7 Ga ferropicrite magmatism: a record of Fe-rich heterogeneities during Neoarchean global mantle melting. | Geochimica et Cosmochimica Acta, in press available 20p. | Canada, Ontario, Quebec | Ungava craton |
| Abstract: Although terrestrial picritic magmas with FeOTOT ?13 wt.% are rare in the geological record, they were relatively common ca. 2.7 Ga during the Neoarchean episode of enhanced global growth of continental crust. Recent evidence that ferropicritic underplating played an important role in the ca. 2.74–2.70 Ga reworking of the Ungava craton provides the impetus for a comparison of ca. 2.7 Ga ferropicrite occurrences in the global Neoarchean magmatic record. In addition to the Fe-rich plutons of the Ungava craton, volumetrically minor ferropicritic flows, pyroclastic deposits, and intrusive rocks form parts of the Neoarchean greenstone belt stratigraphy of the Abitibi, Wawa, Wabigoon and Vermillion domains of the southern and western Superior Province. Neoarchean ferropicritic rocks also occur on five other Archean cratons: West Churchill, Slave, Yilgarn, Kaapvaal, and Karelia; suggesting that ca. 2.7 Ga Fe-rich magmatism was globally widespread. Neoarchean ferropicrites form two distinct groups in terms of their trace element geochemistry. Alkaline ferropicrites have fractionated REE profiles and show no systematic HFSE anomalies, broadly resembling the trace element character of modern-day ocean island basalt (OIB) magmas. Magmas parental to ca. 2.7 Ga alkaline ferropicrites also had high Nb/YPM (>2), low Al2O3/TiO2 (<8) and Sc/Fe (-3 × 10?4) ratios, and were enriched in Ni relative to primary pyrolite mantle-derived melts. The high Ni contents of the alkaline ferropicrites coupled with the low Sc/Fe ratios are consistent with derivation from olivine-free garnet-pyroxenite sources. The second ferropicrite group is characterized by decisively non-alkaline primary trace element profiles that range from flat to LREE-depleted, resembling Archean tholeiitic basalts and komatiites. In contrast to the alkaline ferropicrites, the magmas parental to the subalkaline ferropicrites had flat HREE, lower Nb/YPM (<2), higher Al2O3/TiO2 (8-25) and Sc/Fe (-4 × 10?4) ratios, and were depleted in Ni relative to melts of pyrolitic peridotite; suggesting they were derived from garnet-free peridotite sources. Neodymium isotopic evidence indicates that the source of alkaline ferropicrites was metasomatically enriched shortly before magma generation (-3.0 Ga), but the subalkaline ferropicrites do not show evidence of precursor metasomatism. The metasomatic enrichment of the alkaline ferropicrite sources may have been accompanied by conversion of Fe-rich peridotite to secondary garnet-pyroxenite. Melting experiments on "pyrolitic" compositions and consideration of the dependence of the density of silicate liquids on pressure and temperature, suggest that ferropicrites cannot originate by melting of normal terrestrial mantle (Mg-number = 0.88-0.92) at high pressures and temperatures. The geochemical similarity between the subalkaline ferropicrites and the shergottite-nakhlite-chassigny (SNC) and howardite-eucrite-diogenite (HED) differentiated meteorites suggests, however, that the Fe-rich mantle may originate from the infall of Fe-rich chondritic meteorites. The occurrence of ca. 2.7 Ga Fe-rich rocks on at least six cratons that are commonly coeval with the more ubiquitous komatiites and Mg-tholeiites is consistent with the existence of heterogeneous Fe-rich "plums" throughout the Neoarchean mantle. The paucity of ferropicrites in the post-2.7 Ga geological record suggests that majority of these Fe-rich plums have been melted out during the global Neoarchean melting of the mantle. |
DS201512-1950 2015 | Miller, R.R. | Pantellerite hosted rare earth element mineralization in southeast Labrador: the Foxtrot deposit. | Symposium on critical and strategic materials, British Columbia Geological Survey Paper 2015-3, held Nov. 13-14, pp. 109-118. | Canada, Labrador | Rare earths |
| Abstract: The Foxtrot rare earth element (REE) deposit is hosted by peralkaline volcanic rocks, primarily pantellerite and commendite fl ows and ash-fl ow tuffs, of the Fox Harbour Volcanic belt in southeast Labrador, near the coastal community of St Lewis (Fig. 1). Search Minerals personnel discovered the deposit in 2010 as a result of a REE exploration program in southeast Labrador. Exploration diamond drilling in late 2010, 2011, and early 2012, totalling 72 diamond-drill holes and 18,855 metres, outlined a Dy-Nd-Y-Tb deposit of 9.2 million tonnes indicated resource (cut-off 130 ppm Dy), grading 189 ppm Dy, 1442 ppm Nd and 1040 ppm Y, and, 5.2 million tonnes inferred resource, grading 176 ppm Dy, 1233 ppm Nd, and 974 ppm Y (Table 1; Srivastava et al., 2012, 2013). A smaller highgrade resource (HGC) was also defi ned (Table 1) and was the subject of a Preliminary Economic Assessment (Srivastava et al., 2013). The Foxtrot deposit and the Fox Harbour Volcanic belt have been the target of continued REE exploration and the subject of engineering and metallurgical studies (Srivastava et al., 2012, 2013; Search Minerals 2014, 2015b) to evaluate the possibility of developing a REE mine at Foxtrot and a REE processing plant in the St. Lewis area (Fig. 1). Herein we outline the geology and mineralization of the Foxtrot REE deposit and develop a preliminary exploration model for REE mineralization in the Fox Harbour Volcanic belt and related belts in southeast Labrador. |
DS201512-1951 2015 | Miller, V.S., Naeth, M.A. | Development of soils and plant communities for reclamation in northern diamond mines. | 43rd Annual Yellowknife Geoscience Forum Abstracts, abstract p. 68. | Canada, Northwest Territories | Reclamation |
| Abstract: Reclamation research in the north over the past 30 years has primarily focused on oil and gas and transportation corridor disturbances. Among industries, disturbances caused by infrastructure and transportation corridors are similar. However, each industry has its unique by products that determine which reclamation methods are most appropriate to achieve end land use goals and the relative ease of reclamation. The purpose of this research program is to develop methods to enhance revegetation of disturbed sites at diamond mines in the north, in particular to create soil like substrates on sites where soil has been removed with the use of onsite and commercial materials and to reestablish a diverse native plant community. Reclamation substrates include by products from the diamond mining process like crushed rock, till/lake sediment, processed kimberlite and various combinations of till/lake sediment and processed kimberlite. Greenhouse experiments were also conducted at the University of Alberta to test a range of substrates and amendments with potential to aid reclamation in the field. In 2013 and 2014, research sites were established at Diavik Diamond Mine using the best performing substrates to determine the effect of micro topography, addition of organic matter and erosion control on native grass and forb establishment; effective moss propagation techniques and; effective lichen propagation methods. Preliminary results and observations from completed greenhouse experiments and the first two growing seasons will be discussed. This research directly enhances knowledge and sustainability of northern regions. It will lead to recommendations for enhanced reclamation protocols to be used by industry and government in the north. |
DS201512-1952 2015 | Milligan, R., Fedortchouk, Y., Normandeau, P.X., Fulop, A. | Comparative study of composition and occurrence of apatite in Snap Lake and Ekati kimberlites. | 43rd Annual Yellowknife Geoscience Forum Abstracts, abstract p. 69. | Canada, Northwest Territories | Deposit - Snap Lake, Ekati |
| Abstract: Kimberlites are volcanic ultra-potassic rocks present mostly in cratonic settings and some are diamond bearing. Kimberlite magma is derived from the upper mantle, however, its primary composition is still unknown. Assimilation of mantle and crustal material, loss of volatiles during eruption and high degree of alteration all result in variable compositions of kimberlite magma reaching the surface. Studies have shown that kimberlitic fluid has a significant effect on the quality and preservation of diamonds carried to the surface. By better understanding the primary composition of kimberlites, and the processes that drive kimberlite eruption, we can attempt to gain some diagnostic knowledge of the economic viability of a particular kimberlite. Apatite is a common mineral in kimberlite, which composition is sensitive to volatiles and the presence of magmatic fluid. This study will look at the variation of apatite in kimberlites, how different geology indicates their different fluid histories, and the potential for using apatite as an indicator of fluid content and composition in kimberlite magma. The study uses polished sections from different kimberlite lithologies within the Snap Lake kimberlite and from six Ekati Mine kimberlites. Apatite grains were examined using scanning electron microscope (back scatter imaging) and composition was obtained with wavelength-dispersive spectroscopy mode of electron-microprobe analyzes. Snap Lake is a single dyke of coherent kimberlite facies. The dyke intruded in a near-horizontal orientation, and has an average vertical thickness of 2.5 m. There is significant incorporation of crustal material, and the kimberlite is highly altered, possibly a result of interaction with abundant xenoliths. The studied Ekati kimberlites include: two coherent kimberlites - Grizzly and Leslie, and four kimberlites with resedimented volcaniclastic kimberlite facies – Misery, Koala, Panda, and Beartooth. These kimberlites show significant variations in the apatite crystallizing from the melts. At Snap Lake apatite occurs late, interstitially in the groundmass. These anhedral apatites appear to have no zonation, and crystallize around microphenocrysts of olivine and phlogopite. There is also a late component of apatite, possibly associated with carbonate veins that fracture olivine macrocrysts. Sub- to euhedral apatite grains (max 50 µm) crystalize in a carbonate host within a fracture or crack in olivine macrocrysts. In the Ekati kimberlites, apatite is extremely rare to absent in Misery, Panda, and Beartooth kimberlites, but abundant in Grizzly, Koala, and Leslie. Leslie has plenty of euhedral zoned and unzoned apatite associated with monticellite set in carbonate matrix. Grizzly has abundant small (~10 µm) anhedral apatite. Koala contains both anhedral and euhedral apatite, some of which is zoned. The presentation will report the initial results of this study and possible applications for the behavior of volatiles in the studied kimberlite magmas and examine their relationship with the features of the diamond population. |
DM201505-0897 2015 | Minesite | Conroy discussing kimberlite body in FIn land at Seitapera in the Kuhmo district. | Minesite.com, Apr. 1, 1p. | Europe, Finland | News item - Karelian Diamonds |
DM201506-0898 2015 | Minesite | Five Star Diamonds has a 3.5 hectare kimberlite pipe in the Goais region of Brazil. Construction of a pilot plant has commenced. | Minesite.com, Apr. 30, 1/4p. | South America, Brazil | News item - Five Star |
DM201501-0899 2014 | Mineweb | Alrosa to sell more diamonds direct to India. | Mineweb.com, Dec. 11, 1/2p. | Russia, India | News item - Alrosa |
DM201502-2469 2015 | mineweb | Rough diamond prices drop. | Mineweb.com, Jan. 8, 1p. | Global | News item - prices |
DM201502-2470 2015 | Mineweb | Petra Diamonds sees FY results below market concensus. | Mineweb.com, Jan. 26, 1p. | Africa, South Africa | News item - Petra |
DM201503-0900 2015 | Mineweb | Alrosa sees moderate growth in 2015 diamond sales. | Mineweb.com, Jan. 29, 1p. | Russia | News item - Alrosa |
DM201503-0901 2015 | Mineweb | Diamonds are Anglo's best friend. | Mineweb.com, Feb. 17, 1p. | Global | News item - De Beers |
DM201507-0902 2015 | Mineweb | Botswana's Okavango diamond sales fall 20%. | Mineweb.com, May 28, 1p. | Africa, Botswana | News item - Okavango |
DM201509-0903 2015 | Mineweb | Creditors confident as Zimbabwe consolidates Marange diamond fields. | Mineweb.com, Aug. 2, 1p. | Africa, Zimbabwe | News item - Gye Nyame |
DM201512-2260 2015 | Mineweb | Why is beneficiation in the diamond industry failing? Legislation has become a defining feature of the investment regime and is now a liability. | Mineweb.com, Oct. 28, 2p. | Africa, South Africa, Angola | News item - beneficiation |
DM201512-2261 2015 | Mineweb | Rough diamond bubble bust ( Part 1) M. Rapaport. | Mineweb.com, Nov. 25, 1/4p. | Global | News item - rough markets |
DM201507-0904 2015 | Mining Magazine | Debmarine offshore mining vessel gets heavy lift. Johnson Crane Hire has performed heavy lifting for Gariep off shore vessel. | Mining Magazine, May 29, 1/4p. | Africa, Namibia | News item - Debmarine |
DM201503-0905 2015 | Mining Review | The lab grown diamond threat - a reality in 10-15 years? | Mining Review.com, Feb. 20, 2p. | Technology | News item - synthetics |
DM201506-0906 2015 | Mining.com | De Beers paid only $ 226 in royalties for its Ontario mine last year - report. Victor | Mining.com, May 12, 1p. | Canada, Ontario | News item - De Beers |
DM201506-0907 2015 | Mining.com | Alexkor making progress towards sustainability. Production increase from 46,000 to 79,000 carats. | Mining.com, May 14, 1/2p. | Africa, South Africa | News item - Alexkor |
DM201501-0908 2014 | Miningmx | Zimbabwe, a place of rewards and sanctions. | Miningmx.com, Dec. 9, 1/2p. | Africa, Zimbabwe | News item - legal |
DM201502-2471 2015 | Miningmx | Rockwell unveils $C 28.5 m diamond deal. | Miningmx.com, Jan. 7, 1p. | Africa, South Africa | News item - Rockwell |
DM201503-0909 2015 | Miningmx | Diamond price weakness 'short lived'. | Miningmx.com, Jan. 28, 1p. | Global | News item - prices |
DM201503-0910 2015 | Miningmx | Lace mine to start production in H2. | Miningmx.com, Jan. 30, 1/4p. | Africa, South Africa | News item - DiamondCorp |
DM201503-0911 2015 | Miningmx | Women should become "one of the boys". | Miningmx.com, Feb. 17, 1p. | Global | News item - WIM |
DM201504-0912 2015 | Miningmx | Gemfields to add sapphires to product suite. ( emeralds) | Miningmx.com, Mar. 11, 1/4p. | Africa, Zambia, Mozambique | News item - Gemfields |
DM201504-0913 2015 | Miningmx | Zim diamond miners told to sell 50% in shares. | Miningmx.com, Mar. 13, 1p. | Africa, Zimbabwe | News item - legal |
DM201505-0914 2015 | Miningmx | Timeless De Beers buys priceless time for Anglo. | Miningmx.com, Apr. 2, 2p. | Global | News item - De Beers |
DM201505-0915 2015 | Miningmx | Mugabe says indigenisation is 'generous'. | Miningmx.com, Apr. 9, 1p. | Africa, Zimbabwe | News item - legal |
DM201505-0916 2015 | Miningmx | Rio's Murowa cut output 61% to avoid tax. | Miningmx.com, Apr. 23, 1p. | Africa, Zimbabwe | News item - Rio Tinto |
DM201506-0917 2015 | Miningmx | State Diamond Trade under attack. Allowed to purchase 10% of local diamond producers run of mine … only managed to buy some 4%. | Miningmx.com, May 14, 1p. | Africa, South Africa | News item - SDT |
DM201507-0918 2015 | Miningmx | Trans Hex caps a good year with 10c/s payout. Kleinzee | Miningmx.com, June 2, 1p. | Africa, South Africa, Angola | News item - Trans Hex |
DM201508-0919 2015 | Miningmx | De Beers looks to SA with fresh eyes. | Miningmx.com, July 22, 2p. | Africa, South Africa | News item - De Beers |
DM201509-0920 2015 | Miningmx | Gemfields dancing a merry jig. | Miningmx.com, July 30, 1p. | Africa, Zambia | News item - Gemfields |
DM201510-2109 2015 | Miningmx | Market misery fetters Botswana ambitions. | Miningmx.com, Sept. 11, 3p. | Africa, Botswana | News item - economics |
DM201511-2152 2015 | Miningmx | SA diamond sector dying on the vine. Zlotowski's Diamond Cutting Works intending to close its doors. | Miningmx.com, Oct. 6, 2p. | Africa, South Africa | News item - Zlotowski |
DM201511-2153 2015 | Miningmx | De Beers cuts 2015 production forecast again. Jwaneng and Orapa | Miningmx.com, Oct. 25, 1p. | Africa, Botswana | News item - Debswana |
DS201507-0327 2015 | Mints, M.V. | Post collisional lamproites of the Por'ya Guba dike fields. | East European Craton: Early Precambrian history & 3 D. Model Authors: M.V. Mints, K.A. Dokukina, A.N. Konilov, I.B. Philippova, C.L. Zlobin., GSA SPE 510, 433p. Chapter 11, section 3 | Russia, Kola Peninsula | Lamproite |
DS201507-0328 2015 | Mironov, V.P., Rakevich, A.L., Stepanov, F.A., Emelyanova, A.S., Zedgenizov, D.A., Shatsky, V.S., Kagi, H., Martynovich, E.F. | Luminescence in diamonds of the Sao Luiz placer ( Brazil). | Russian Geology and Geophysics, Vol. 56, pp. 729-736. | South America, Brazil | Diamond luminesence |
DS201506-0284 2015 | Miyahara, M., Ohtani, E., El Goresy, A., Lin, Y., Feng, L.,Zhang, J-C., Gillet, P., Nagase, T., Muto, J., Nishijima, M. | Unique large diamonds in a urelilite from Almahat a Sitta TC3, asteroid. | Geochimica et Cosmochimica Acta, Vol. 163, pp. 14-26. | Technology | Urelilite |
DM201501-0921 2014 | Mmegi Online | Debswana squeezes first carats from tailings dumps. | Mmegi.com, Dec. 2, 2p. | Africa, Botswana | News item - Debswana |
DM201508-0922 2015 | Mmegi Online | BCL ( Bamangwato Concessions) mentions ongoing exploration for diamonds in the western part of the country. | mmegi.bw, June 29, 1/8p. | Africa, Zimbabwe | News item - BCL |
DS201510-1789 2015 | Moe, K.S., Yang, J-S, Johnson, P., Xu, X., Wang, W. | Microdiamonds in chromitite and peridotite. Type 1aB and 1b | GSA Annual Meeting, Paper 300-5, 1p. Abstract only Booth | Russia | Spectroscopy |
DS201506-0285 2015 | Molnar, P. | Gravitational instability of mantle lithosphere and core complexes. | Tectonics, Vol. 34, 3, pp. 478-487. | Mantle | Geophysics - seismics |
DC201506-1592 2015 | Monax Mining | Kimberlite project update on EL 5347 proposed drilling. | Monax Mining, Apr. 29, 1/4p. | Australia | News item - press release |
DC201501-1593 2014 | Monax Mining Limited | Additional kimberlites identified near Monax's Maragaret Dam project in S.A. | Monax Mining Limited, Nov. 30, 5p. | Australia | News item - press release |
DC201507-1594 2015 | Monax Mining Limited | Kimberlite project update … Margaret Dam tenement for drilling. | Monax Mining Limited, May 29, 1p. | Australia | News item - press release |
DC201507-1595 2015 | Monax Mining Limited | Kimberlite project - drilling commenced on the Margaret Dam licence 5347. | Monax Mining Limited, June 26, 4p. | Australia | News item - press release |
DC201508-1596 2015 | Monax Mining Limited | Margaret Dam project - drilling completed. | Monax Mining Limited, July 6, 1p. | Australia | News item - press release |
DC201509-1597 2015 | Monax Mining Limited | Quarterly report … Margaret Dam tenement update p. 6. | Monax Mining Limited, July 30, 16p. | Australia | News item - press release |
DC201512-2445 2015 | Monax Mining Limited | PACE funding for maiden kimberlite drilling on EL 5347 | Monax Mining Limited, Oct. 31, 1p. | Australia | News item - press release |
DS201501-0021 2014 | Montsion, J.M. | Disrupting Canadian sovereignty? The First Nations & Chin a strategy revisited. | Geoforum, Vol. 58, pp. 114-121. | Canada | Legal - CSR |
DS201501-0022 2014 | Moore, A.E. | The origin of large irregular gem-quality type II diamonds and the rarity of blue type IIB varieties. | South African Journal of Geology, Vol. 117, pp. 233-250. | Africa, South Africa, Lesotho | Type 11 diamonds |
DS201502-0081 2015 | Moore, M., Chakhmouradian, A.R., Mariano, A.N., Sidhu, R. | Evolution of rare-earth mineralzation in the Bear Lodge carbonatite, Wyoming: mineralogical and isotopic evidence. | Ore Geology Reviews, Vol. 64, pp. 499-521. | United States, Wyoming, Colorado Plateau | Deposit - Bear Lodge |
DS201502-0082 2014 | Moreno Chavez, G., Sarocchi, D., Arce Santana, E., Borselli, L. | Using Kinect to analyze pebble to block-sized clasts in sedimentology. | Computers & Geosciences, Vol. 72, pp. 18-32. | Technology | Not specific to diamonds |
DS201503-0162 2015 | Mosate, M.R. | Debswana Diamond Company: sustainable water use. | PDAC 2015, Abstract, 1p. | Africa, Namibia | CSR - water |
DS201506-0286 2015 | Motoki, M.H., Ballmer, M.D. | Intraplate volcanism due to convective instability of stagnant slabs in the mantle transition zone. | Geochemistry, Geophysics, Geosystems: G3, Vol. 16, 2, pp. 538-551. | Mantle | Subduction |
DC201502-1600 2015 | Mountain Province Diamonds Inc. | Mountain Province Diamonds updates term loan facility. $ US370 million | Mountain Province Diamonds Inc., Jan. 8, 1p. | Canada, Northwest Territories | News item - press release |
DC201503-1601 2015 | Mountain Province Diamonds Inc. | Mountain Province Diamonds announces credit approval for US$370 M term loan facility. | Mountain Province Diamonds Inc., Feb. 3, 1p. | Canada, Northwest Territories | News item - press release |
DC201503-1602 2015 | Mountain Province Diamonds Inc. | Mountain Province Diamonds announces C$95 M rights offering. | Mountain Province Diamonds Inc., Feb. 18, 3p. | Canada, Northwest Territories | News item - press release |
DC201504-1598 2015 | Mountain Province Diamonds Inc. | Announces diamond recovery results from 2014 Tuzo Deep drill program. | Mountain Province Diamonds, Mar. 4, 2p. | Canada, Northwest Territories | News item - press release |
DC201504-1599 2015 | Mountain Province Diamonds Inc. | Mountain Province Diamonds provides Gahcho Kue project update. | Mountain Province Diamonds, Mar. 17, 3p. | Canada, Northwest Territories | News item - press release |
DC201505-1603 2015 | Mountain Province Diamonds Inc. | Mountain Province Diamonds announces completion of primary syndication of US $ 370 million term loan facility. | Mountain Province Diamonds Inc., Mar. 25, 1p. | Canada, Northwest Territories | News item - press release |
DC201505-1604 2015 | Mountain Province Diamonds Inc. | Mountain Province Diamonds C$95 million rights offering completed and oversubscribed. | Mountain Province Diamonds Inc., Mar. 31, 1p. | Canada, Northwest Territories | News item - press release |
DC201505-1605 2015 | Mountain Province Diamonds Inc. | Mountain Province Diamonds closes term loan facility to fund Gahcho Kue to commercial production. | Mountain Province Diamonds Inc., Apr. 7, 2p. | Canada, Northwest Territories | News item - press release |
DC201506-1607 2015 | Mountain Province Diamonds Inc. | Mountain Province Diamonds welcomes Societe Generale to lending syndicate. | Mountain Province Diamonds Inc., May 7, 2p. | Canada, Northwest Territories | News item - press release |
DC201508-1606 2015 | Mountain Province Diamonds Inc. | Mountain Province's Gahcho Kue diamond mine 62 percent complete. | Mountain Province Diamonds Inc., July 7, 1p. | Canada, Northwest Territories | News item - press release |
DC201511-2393 2015 | Mountain Province Diamonds Inc. | Updates Gahcho Kue… overall project more than 70 % complete.. On plan and budget for first production H2 2016. | Mountain Province Diamonds Inc., Oct. 6, 3p. | Canada, Northwest Territories | News item - press release |
DC201511-2394 2015 | Mountain Province Diamonds Inc. | Mountain Province appoints vice president diamond marketing. R. Mackie | Mountain Province Diamonds Inc., Oct. 15, 1p. | Canada, Northwest Territories | News item - press release |
DS201512-1953 2015 | Muir, R.J. | Digital field mapping - making the change from paper to touchscreen technology. | Geology Today, Vol. 31, 6, pp. 232-236. | Technology | Mapping |
| Abstract: Current desktop technology is largely mouse-driven, but many analysts predict that in less than five years we will have a professional workforce that have only experienced learning in a touchscreen environment. Midland Valley have developed a digital mapping tool for smartphones called FieldMove Clino, which has been downloaded more than 20 000 times over the past year. The free version offers an effective way of introducing students to digital field mapping. However, many geoscience departments and teachers of field mapping have yet to make the switch from traditional paper-based methods to digital technology. This article aims to answer some of the frequently asked questions about digital field mapping and outlines some of the advantages for improving field skills and geological thinking in students. |
DS201510-1790 2015 | Muirhead, J.D., Kattenhorn, S.A., Le Corvec, N. | Unravelling the complexity of upper crustal dike networks in continental rifts: examples from East Africa. | Geochemistry, Geophysics, Geosystems: G3, Vol. 16, in press available | Africa, East Africa | Dyke swarms |
| Abstract: The role of dike intrusion in driving continental breakup is fundamental to our understanding of plate tectonics. Buck (2004) showed that the breakup of thick continental lithosphere requires more than far-field tectonic forces, illustrating the important role of dike opening in driving extension during the earliest stages of rifting. Upper crustal diking in rift environments is often depicted to occur through long (up to 80 km), sub-parallel swarms intruding along the full length of rift basins. These assertions are supported by recent dike-driven rifting events in Iceland and Ethiopia (Wright et al., 2012), and inform numerical modelling studies addressing the mechanical effects of dike intrusion to rift processes (e.g., Buck et al., 2005).
Our current view of dike networks, however, may be biased to evolved (>20 Ma), oceanic (e.g., Krafla) or nascent (e.g., Dabbahu-Manda-Hararo) spreading centers. This is largely because magmatic rifting occurs in these regions with a high enough frequency that it can be persistently captured using modern-day monitoring techniques (e.g., InSAR and seismicity). Dike networks throughout other sectors of the East African Rift may instead exhibit greater complexity, particularly in early-stage rifts (<10 Ma) undergoing infrequent diking episodes (Calais et al., 2008). By unravelling the contributions of dikes in these basins we can further refine our understanding of the role of magmatism during continental rift initiation.
Current geophysical techniques (e.g., seismic reflection) lack the capacity to resolve thin, sub-vertical structures in the sub-surface, and thus reconstructing the geometries of cooled, upper crustal dike swarms poses a significant challenge. Recent structural and volcanological studies in both active and eroded monogenetic volcanic fields have illustrated the utility of volcanic vent alignments and cone morphometrics for inferring the distributions and orientations of upper crustal dikes (Kiyosugi et al., 2012; Le Corvec et al., 2013; Keir et al., 2015). The East African Rift exhibits numerous monogenetic cone fields that may help us understand the distribution and geometry of shallow dike-feeders emplaced in the last few million years (Korme et al., 1997; Mazzarini et al., 2013). Building on these studies and methods, we performed a comparative analysis of upper crustal diking in various rift basins throughout East Africa, based on the distributions, alignments and morphologies of monogenetic cones (Muirhead et al., 2015). |
DS201502-0083 2014 | 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-7 | Journal of the Geological Society of India, Vol. 84, 6, pp. 633-644. | India, South India | Kalyandurg cluster |
DC201508-1608 2015 | Mustang Resources Ltd. | Update on Save River project. | Mustang Resources , July 15, 2p. | Africa, Mozambique | News item - press release |
DC201508-1609 2015 | Mustang Resources Ltd. | Save River IR. | Mustang Resources , July 24pp. | Africa, Mozambique | News item - press release |
DC201511-2395 2015 | Mustang Resources Ltd. | Continuing diamond recovery and expansion at Save River. | Mustang Resources Ltd., Oct. 1, 2p. | Africa, Mozambique | News item - press release |
DC201511-2396 2015 | Mustang Resources Ltd. | Save River diamond project - update. | Mustang Resources Ltd., Oct 19, 18p. | Africa, Mozambique | News item - Mustang |
DC201503-1610 2015 | Mwana Africa plc. | Excerpt - diamonds - Klipspringer… price per carat $ 19.31. | Mwana Africa plc., Feb. 16, 1/2p. | Africa, South Africa | News item - press release |
DC201505-1611 2015 | Mwana Africa plc. | Update section: diamonds - Klipspringer . | Mwana Africa plc., Apr. 16, 1/2p. | Africa, South Africa | News item - press release |
DC201511-2397 2015 | Mwana Africa plc. | Mwana Africa changing name to Asa Resources. | Mwana Africa plc., Oct. 1, 1p. | Africa, South Africa | News item - press release |
DS201502-0084 2015 | 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, Quebec | Carbonatite |
DS201511-1865 2015 | 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, Quebec | Carbonatite |
| 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. |
DM201512-2328 2015 | National Post | Diamond jackpot is historic, says Canadian miner. Stone believed second -largest ever found. | National Post Newspaper, Nov. 19, 1/2p. | Africa, Botswana | News item - press release |
DS201502-0085 2015 | Nature Geoscience | Russia's scientific legacy. See Feb hilight Front cover page for search string | Nature Geoscience, Vol. 8, 1p. | Technology | History - Lomonosov University |
DS201512-1954 2015 | Nature Geoscience | Protect sites and samples…. Field samples. | Nature Geoscience, Vol. 8, 11, p. 815. | Global | Field samples |
DS201505-0244 2015 | Navon, O. | Granulitic xenoliths and the formation of the lower crust below southern Syria and northern Israel and Jordan. | Israel Geological Society, Abstracts 1p. | Europe, Syria, Israel, Jordan | Mineralogy |
DS201506-0287 2015 | Nedosekova, I.L., Belousova, E.A., Belyatsky, B.V. | Hf isotopes and trace elements as indicators of zircon genesis in the evolution of the alkaline-carbonatite magmatic system ( Il'meno-Visnevogorskii complex, Urals, Russia.) | Doklady Earth Sciences, Vol. 461, 2, pp. 384-389. | Russia, Urals | Carbonatite |
DS201510-1791 2015 | Nelson, W.R., Furman, T., Pitcavage, E.M. | Exploring the link between metasomatized lithosphere and continental rifting: a case study of the East African Rift. | GSA Annual Meeting, Paper 131-2, 1p. Abstract only | Africa | SCLM |
| Abstract: The subcontinental lithospheric mantle (SCLM) is foundational to understanding the construction, destruction, and division of tectonic plates. Tectonic processes, in turn, both directly and indirectly influence the lithosphere’s thermal, physical and mineralogical properties. Mantle melting and melt/fluid percolation cause fundamental changes to the lithosphere that affect its composition and stability. Specifically, metasomatism by silicate melts and hydrous/carbonated fluids can create lithologies (i.e. pyroxenites) that are denser, more fusible, and less viscous than adjacent peridotite. The resulting density instabilities may lead to lithospheric erosion, topographic uplift and even continental rifting. We explore the link between metasomatized SCLM, mafic volcanism and associated continental rifting in the Ugandan portion of the Western Rift of the East African Rift System using Re-Os isotopes from both alkaline mafic lavas and pyroxenite mantle xenoliths. The lavas record age-corrected 187Os/188Os that range from 0.1421 to 0.2105, which is more radiogenic than primitive mantle (0.1296; Meisel et al., 2001). These data demonstrate that many of the lavas were derived from a metasomatized mantle source though a few have experienced crustal contamination. The mantle xenoliths also record a wide range of 187Os abundances. One peridotite xenolith has a mildly radiogenic signature (187Os/188Os = 0.1342) whereas the pyroxenites span a wide range of 187Os/188Os ratios (0.1401-0.5052). One pyroxenite recorded a mildly unradiogenic 187Os/188Os value (0.127) and has 0.96 ppb of Os. Based on these data, we conclude that the lavas were derived from metasomatized SCLM. Some of the SCLM was sampled by mantle xenoliths but, as a whole, the SCLM is more heterogeneous than the lavas suggest. The widespread, metasomatized SCLM readily contributed to melt generation both in situ as well as during foundering via lithospheric drip (Furman et al., in review). The SCLM-derived volcanism occurred prior to and during Western Rift extension, suggesting that the metasomatized SCLM played a vital role in rift development. |
DS201501-0023 2014 | Nemeth, P. | Asteroid impacts on Earth make structurally bizarre diamonds. Diamond grains from the Canyon Diablo meterorite | Nature Communications, Nov. 20, 2p. | United States, Arizona | Lonsdaleite |
DS201504-0211 2015 | Nestola, F. | The crucial role of crystallography in diamond research. | Rendiconzi Lincei Scienze Fisiche E Naturel, Vol. 26, 2, pp. 225-233. | Mantle | Diamond inclusions |
DS201502-0086 2015 | Neuser, R.D., Schertl, H-P., Logvinova, A.M., Sobolev, N.V. | An EBSD study of olivine inclusions in Siberian diamonds: evidence for syngenetic growth? | Russian Geology and Geophysics, Vol. 56, 1, pp. 321-329. | Russia | Diamond morphology |
DC201508-1612 2015 | New Nadina Explorations Limited | New Nadin a Explorations Limited to acquire Kettle River Resources Ltd. | New Nadina Explorations Limited, July 20, 1p. | Canada, Northwest Territories | News item - press release |
DC201505-1613 2015 | Newfield Resources Limited | DMS plant successfully commissioned. Allotropes diamond project, SL. | Newfield Resources Limited, Mar. 31, 1p. | Africa, Sierra Leone | News item - press release |
DC201506-1614 2015 | Newfield Resources Limited | Allotropes diamond project - JORC alluvial exploration target. | Newfield Resources Limited, Apr. 20, 5p. | Africa, Sierra Leone | News item - press release |
DC201508-1615 2015 | Newfield Resources Limited | Mining licence granted at Allotropes diamond project. Golu sites ( Sewa River system) | Newfield Resources Limited, July 1, 3p. | Africa, Sierra Leone | News item - press release |
DC201509-1616 2015 | Newfield Resources Limited | Sierra Leone diamond projects.. Golu | Newfield Resources Limited, July 31, 34p. | Africa, Sierra Leone | News item - press release |
DC201511-2398 2015 | Newfield Resources Limited | Review of activities .. Alluvial | Newfield Resources Limited, Sept. 30, 60p. | Africa, Sierra Leone | News item - press release |
DC201512-2446 2015 | Newfield Resources Limited | Golu bulk sampling.. Planning for follow up airborne mag survey targets, drill testing and plan for advanced stage dredging program on Sewa River. | Newfield Resources Limited, Oct. 30, 1p. Highlights | Africa, Sierra Leone | News item - press release |
DS201503-0163 2015 | Newton, A. | Archean Earth: alkaline lakes of old. | Nature Geoscience, Vol. 8, p. 90. | Mantle | Alkalic |
DS201502-0087 2015 | Nikolenko, E., Tychkov, N., Afanasiev, V. | Mantle xenocrysts of the Chompolo kimberlite field, Aldan shield, south Yakutia. | Economic Geology Research Institute 2015, Vol. 17,, # 2471, 1p. Abstract | Russia | Deposit - Chompolinskoe |
DS201502-0088 2015 | Nimis, P., Goncharov, A., Ionov, D.A., McCammon, C. | Fe3 partitioning systematics between orthopyroxene and garnet in mantle peridotite xenoliths and implications for thermobarometry of oxidized and reduced mantle rocks. | Contributions to Mineralogy and Petrology, Vol. 169, 6p. | Mantle | Peridotite |
DS201506-0288 2015 | Nkono, C., Femenias, O., Lene, A., Mercier, J-C., Ngounouno, F.Y., Demaiffe, D. | Relationship between the fractal dimension of orthopyroxene distribution and the temperature in mantle xenoliths. | Geological Journal, in press available | Russia, Poland | Xenoliths |
DS201510-1792 2015 | Nkoudandou, O.F., Bardintzeff, J-M., Fagny, A.M. | Sub-continental lithospheric mantle structure beneath the Adamawa plateau inferred from the petrology of ultramafic xenoliths from Ngaoundere, Cameroon, Central Africa. | Journal of African Earth Sciences, Vol. 111, pp. 26-40. | Africa, Cameroon | Lherzolite, Harzburgite, Olivine websterite |
| Abstract: Ultramafic xenoliths (lherzolite, harzburgite and olivine websterite) have been discovered in basanites close to Ngaoundéré in Adamawa plateau. Xenoliths exhibit protogranular texture (lherzolite and olivine websterite) or porphyroclastic texture (harzburgite). They are composed of olivine Fo89-90, orthopyroxene, clinopyroxene and spinel. According to geothermometers, lherzolites have been equilibrated at 880-1060 °C; equilibrium temperatures of harzburgite are rather higher (880-1160 °C), while those of olivine websterite are bracketed between 820 and 1010 °C. The corresponding pressures are 1.8-1.9 GPa, 0.8-1.0 GPa and 1.9-2.5 GPa, respectively, which suggests that xenoliths have been sampled respectively at depths of 59-63 km, 26-33 km and 63-83 km. Texture and chemical compositional variations of xenoliths with temperature, pressure and depth on regional scale may be ascribed to the complex history undergone by the sub-continental mantle beneath the Adamawa plateau during its evolution. This may involve a limited asthenosphere uprise, concomitantly with plastic deformation and partial melting due to adiabatic decompression processes. Chemical compositional heterogeneities are also proposed in the sub-continental lithospheric mantle under the Adamawa plateau, as previously suggested for the whole Cameroon Volcanic Line. |
DC201502-1617 2015 | North Arrow Minerals Inc. | North Arrow updates Qilaugaq bulk sample processing. | North Arrow Minerals Inc., Jan. 21, 2p. | Canada, Nunavut | News item - press release |
DC201504-1618 2015 | North Arrow Minerals Inc. | North Arrow reports initial diamond recoveries from the first 609 tonnes of Qialugaq sample… two +4 carat yellow diamonds recovered. Q1-4 | North Arrow Minerals Inc., Feb. 26, 2p. | Canada, Nunavut | News item - press release |
DC201505-1619 2015 | North Arrow Minerals Inc. | North Arrow discovers three new kimberlites at the Pikoo diamond project, Saskatchewan.. PK314 drilled to depth of 213m and PK 150 drilled to 199 m. | North Arrow Minerals Inc., Mar. 30, 3p. | Canada, Saskatchewan | News item - press release |
DC201505-1620 2015 | North Arrow Minerals Inc. | North Arrow reports yellow diamonds from Q1-4 kimberlite are rare type 1b diamonds. Qilalugaq project | North Arrow Minerals Inc., Apr. 21, 2p. | Canada, Nunavut | News item - press release |
DC201506-1621 2015 | North Arrow Minerals Inc. | North Arrow reports final diamond recoveries from Qilalugaq bulk sample. | North Arrow Minerals Inc., May 5, 2p. | Canada, Northwest Territories | News item - press release |
DC201506-1622 2015 | North Arrow Minerals Inc. | North Arrow announces $ 3 million private placement. | North Arrow Minerals Inc., May 8, 1p. | Canada, Northwest Territories | News item - press release |
DC201507-1623 2015 | North Arrow Minerals Inc. | North Arrow announces closing of $ 4 million bought deal. | North Arrow Minerals Inc., May 28, 1p. | Canada, Northwest Territories | News item - press release |
DC201507-1624 2015 | North Arrow Minerals Inc. | North Arrow updates the Redemption diamond project, Lac de Gras. | North Arrow Minerals Inc., June 2, 1p. | Canada, Northwest Territories | News item - press release |
DC201507-1625 2015 | North Arrow Minerals Inc. | North Arrow reports diamond valuation results from the Qilalugaq project. | North Arrow Minerals Inc., June 9, 1p. | Canada, Northwest Territories | News item - press release |
DC201510-2357 2015 | North Arrow Minerals Inc. | North Arrow confirms high diamond counts from Pk150 kimberlite Pikoo. | North Arrow Minerals Inc., Sept. 8, 2p. | Canada, Saskatchewan | News item - press release |
DC201510-2358 2015 | North Arrow Minerals Inc. | North Arrow completes till sampling at the Mel diamond project, Nunavut. | North Arrow Minerals Inc., Sept. 16, 1p. | Canada, Nunavut | News item - press release |
DC201511-2399 2015 | North Arrow Minerals Inc. | North Arrow confirms four Diamondiferous kimberlites at Pikoo diamond project, Saskatchewan. PK314 and PK311 ( prev. PK150 drilled) | North Arrow Minerals Inc., Oct. 20, 3p. | Canada, Saskatchewan | News item - press release |
DC201503-1626 2015 | Northland Capital Partners Limited | Paragon Diamonds … initiation: an emerging integrated diamond producer. Lemphane | Northland Capital Partners Limited Research Report, Feb. 2, 36p. | Africa, Lesotho | News item - Paragon |
DC201503-1627 2015 | Nouveau Monde Mining Enterprises Inc. | Waasikuu kimberlite targets drilled . No kimberlitic rocks. | Nouveau Monde Mining Enterprises, Feb. 5, 1/8p. | Canada, Quebec | News item - press release |
DS201507-0329 2015 | Novella, D., Bolfan-Casanova, N., Nestola, F., Harris, J.W. | H2O in olivine and garnet inclusions still trapped in diamonds from the Siberian craton: implications for the water content of cratonic lithosphere peridotites. | Lithos, Vol. 230, pp. 180-183. | Russia | Deposit - Udachnaya |
DS201512-1955 2015 | Novy, L., Petherbridge, W. | Ekati Long Lake containment facility reclamation research. | 43rd Annual Yellowknife Geoscience Forum Abstracts, abstract p. 76. | Canada, Northwest Territories | Deposit - Ekati |
| Abstract: The Ekati Diamond Mine is a surface and underground diamond mine operated by Dominion Diamond Ekati Corporation. It is located near the Lac de Gras Northwest Territories, Canada approximately 300 km north of Yellowknife and roughly 200 km south of the Arctic Circle. The Ekati Long Lake Containment Facility (LLCF) is a five celled containment area for storage of processed kimberlite generated during the processing and extraction of diamonds from kimberlite ore. The LLCF has been in operation since 1998 and deposition of processed kimberlite has occurred within the three northern cells with the remaining two cells being used for water quality “polishing” to help meet discharge criteria. The Interim Closure and Reclamation Plan for Ekati outlines a plan to cover the LLCF kimberlite surface with a combination of rock and vegetation. The cover system looks to fulfill the closure objective of physically stabilizing the processed kimberlite and creating a landscape safe for wildlife and human use. Cell B of the LLCF has reached its capacity and is being used as a reclamation research area. The purpose of the reclamation research is to identify a long term cover design that can be expanded to the whole LLCF. A winter drilling investigation in Cell B of the LLCF was undertaken in 2013. The objective of the investigation was to characterize the processed kimberlite and its porewater chemistry. Results from the investigation indicated that permafrost has aggraded into the kimberlite and surface zone pore water concentrations were higher when compared to process plant discharge. In fall of 2013 various areas of Cell B were seeded with annual and perennial vegetation ground covers. Further seeding of Cell B was completed in the summer of 2014. Seed from a variety of sources that includes locally harvested and commercially available native plants and farm crops was applied at different rates using different seeding techniques. In the winter of 2013 rock was placed in various configurations within the seeded areas to evaluate its effects on vegetation growth and erosion control. A total of 25 hectares has been seeded in Cell B since the fall of 2013 and the results of initial monitoring are positive regarding establishment of long term ground cover on the kimberlite. |
DS201506-0289 2015 | Nowacki, A., Kendall, J-M., Wookey, J., Pemberton, A. | Mid mantle anisotropy in subduction zones and deep water transport. | Geochemistry, Geophysics, Geosystems: G3, Vol 16, 3, pp. 764-784. | Mantle | Subduction |
DM201501-0923 2014 | Nunatsiaqonline.ca | Abandoned Nunavut diamond mine now belongs to the crown. Court documents show Shear Diamonds has legally forfeited assets and mineral leases Jericho | Nunavut news, Dec. 19, 1p. | Canada, Nunavut | News item - Jericho |
DS201510-1793 2015 | Nutman, A.P., Bennett, V.C., Friend, C.R.L. | Proposal for a continent 'Itsaqia' amalgamted at 3.66 Ga and rifted apart from 3.53 Ga: initiation of a Wilson Cycle near the start of the rock record. | American Journal of Science, Vol. 315, 6, pp. 509-536. | Canada | Acasta Gneiss |
| Abstract: A synthesis of the geological record of Earth's ten remaining oldest surviving gneiss complexes, each containing >3.6 Ga rocks, reveals a common history. We propose that the simplest scenario compatible with all observations is that of formation of an ancient continental mass, here named Itsaqia, by 3.66 Ga from amalgamation of earlier quartzofeldspathic crust, followed by initiation of continental break-up at 3.53 Ga by rifting. Evidence for this is reconstructed from the remaining oldest rock record (only ca. 10,000 km2 globally).
Dominating the surviving fragments of the proposed Itsaqia continent are 3.9 to 3.66 Ga tonalites that represent juvenile crustal additions with whole-rock initial ?Nd >+1 and zircon initial ?Hf ? 0. Their trace element chemistry shows that they were derived by ca. 30 percent partial melting of garnetiferous, mostly eclogitized basic rocks, leaving behind a subcrustal garnet-rich restite. The tonalites contain inclusions of mafic rocks with chemical signatures diagnostic of mantle wedge fluxing, such as enrichment in the light rare earths and depletion of Nb and Ti. We interpret that this juvenile crust formed repeatedly in arc-like constructs at convergent plate boundaries. The Acasta Gneiss of Canada is the only undisputed surviving rock record of the proposed Itsaqia continent where crust formation extends back to the Hadean.
Before ca. 3.66 Ga, individual gneiss complexes show distinct chronologies of crust formation, yet despite their present-day isolation, they underwent identical 3.66 to 3.6 Ga high temperature orogenic events (Isukasian orogeny) – which we contend indicates that from 3.66 Ga these complexes had amalgamated into a single continental mass. Rare surviving 3.66 Ga high-pressure granulite rocks that underwent rapid decompression indicate tectonic crustal thickening then collapse during amalgamation. This was followed by almost 50 million years of high heat flow and lower pressure metamorphism, most probably in an extensional setting.
Starting from ca. 3.53 Ga, we propose that komatiite and basalt eruption and dike emplacement marked the start of Itsaqia's dismemberment by rifting. We further speculate that the deep mantle upwelling responsible for this plume-related magmatism was triggered by either the cascade of pre-3.66 Ga sub-Itsaqia high density garnet-rich restitic subduction graveyards into the lower mantle or the thermal insulation effect of Itsaqia. This resembles the mechanisms of supercontinent breakup throughout Earth's history. Hence we propose that Wilson Cycles of continent amalgamation and breakup were already initiated by the Eoarchean, near the start of the rock record. Australia's East Pilbara region was over the top of the plume, where the thermal impact destroyed Itsaqia by melting to give rise to felsic igneous rocks coeval with komatiites. Greenland's Itsaq Gneiss Complex was peripheral to the plume, and hence was heavily diked at ca. 3.5 Ga, but was not melted. |
DM201501-0924 2014 | ODBA | Online Diamond Buying Advice unveils new diamond search tool and website re-launch. | Online Diamond Buying Advice, Dec. 9, 1p. | Technology | News item - ODBA |
DC201502-1628 2015 | OGI Group | Increase in underwriting commitment and commencement of trial mining program Save River diamonds project. | OGI Group Limited, Jan. 7, 1p. | Africa, Mozambique | News item - press release |
DS201510-1794 2015 | 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 only | Africa, South Africa | Carbonatite |
| 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 |
DS201510-1795 2015 | Ohtani, E. | Hydrous minerals and the storage of water in the deep mantle. | Chemical Geology, Vol. 418, pp. 6-15. | Mantle | Water |
| Abstract: Water is transported into the deep mantle via hydrous minerals in subducting slabs. During subduction, a series of minerals in these slabs such as serpentine or chlorite, Mg-sursassite and/or the 10 Å phase, and phase A can be stable at different pressures within the slab geotherms, and may transport significant amount of water into the Earth's interior. The transition zone has a large water storage capacity because of the high solubility of water in wadsleyite and ringwoodite. The recent discovery of hydrous ringwoodite and phase Egg as inclusions in ultra deep diamonds from Juina, Brazil suggests that the transition zone may indeed contain water. Seismic tomographic studies and electrical conductivity observations suggest that the transition zone may contain large amount of water, at least locally, beneath the subduction zones. The discovery of a new hydrous phase H, MgSiO2(OH)2, and its solid solution with isostructural phase ?-AlOOH, suggests that a significant amount of water could be stored in this hydrous magnesium silicate phase which is stable down to the lower mantle. Water may be transported into the bottom of the lower mantle via phase H–? solid solution in descending slabs. This new high pressure hydrous phase solid solution has a high bulk modulus and sound velocity owing to strong O-H bonding due to hydrogen bond symmetrization in the lower mantle. Therefore, water stored in this hydrous phase would not reduce the seismic wave velocity in the lower mantle, and is seismically invisible. Dehydration melting could then occur at the base of the lower mantle, providing a potential explanation for the ultralow-velocity zone at the core-mantle boundary. When this hydrous magnesium silicate phase or hydrous melt makes contact with the metallic outer core at the core-mantle boundary, then hydrogen is likely to dissolve into the core. |
DS201503-0164 2015 | Ohtani, E., Amaike, Y., Kamada, S., Sakamaki, T., Hirao, N. | Stability of hydrous phase H MgSi04H2 under lower mantle conditions. | Geophysical Research Letters, Vol. 41, 23, pp. 8283-8287. | Mantle | Mineralogy |
DS201512-1956 2015 | O'Keefe, M. | Rough year creates opportunity in diamonds. | Diamonds in Canada Magazine, Northern Miner, Nov. pp. 5-9. | Global, Canada | Diamond industry |
DS201508-0370 2015 | O'Leary, M.C., Lange, R.A., Ai, Y. | The compressability of CaCO3-Li2CO3-Na2CO3-K2CO3 liquids: application to natrocarbonatite and CO2- bearing nephelinite liquids from Oldoinyo Lengai. | Contributions to Mineralogy and Petrology, Vol. 170, 18p. | Africa, Tanzania | Deposit - Oldoinyo Lengai |
DC201501-1629 2014 | Olivut Resources Ltd. | Exploration and funding update. | Olivut Resources Ltd., Dec. 16, 1p. | Canada, Northwest Territories | News item - press release |
DC201505-1630 2015 | Olivut Resources Ltd. | Funding and exploration update on HOAM project. | Olivut Resources Ltd., Mar. 30. 1p. | Canada, Northwest Territories | News item - press release |
DC201511-2400 2015 | Olivut Resources Ltd. | Olivut announces private placement of flow through shares and common shares. | Olivut Resources Ltd., Sept. 30, 1p. | Canada, Northwest Territories | News item - press release |
DS201503-0165 2015 | O'Neill, C., Lenardic, A., Condie, K.C. | Earth's punctuated tectonic evolution: cause and effect. | Geological Society of London Special Publication: Continent formation through time., No. 389, pp. 17-40. | Mantle | Geotectonics |
DS201510-1796 2015 | 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 Booth | Technology | GIA 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. |
DS201512-1957 2015 | Paget, M., Chiaramello, P. | Goldsim water balance modeling of waste rock piles, Ekati waste rock storage area ( Ekati WRSA). | 43rd Annual Yellowknife Geoscience Forum Abstracts, abstract p. 77. | Canada, Northwest Territories | Deposit - Ekati |
| Abstract: The Ekati Waste Rock Storage Piles (WRSA) water balance model was developed in Goldsim as a module designed to support water quality estimates. The water balance module accounts for direct precipitation, snowmelt, seepage, runoff, and delays to flow within the WRSA. As the Ekati Mine is located within a climate zone of continuous permafrost, a portion of the water infiltrating the WRSA’s becomes trapped within the waste rock as ice when it encounters sub-freezing internal temperatures. Seepage leaching from the WRSAs is thus limited to the outer surface of the WRSAs (active layer) where water produced by melting of seasonal surficial ice and snow. The active layer was modeled by detaining all water in the WRSA from October to the end of June. After June the water was released from the layer using a delay function, which is described below. The model divides seepage and runoff into three physically-based flow paths. ? The primary flow path is of water that falls infiltrates vertically through the waste rock until it encounters an impermeable lens of ice-saturate rock, and travels horizontally, to ultimately emerge at the toe of the WRSAs. ? The secondary flow path is water that falls on the outer slopes of the WRSAs and seeps under the outer slopes to the toe. ? The third flow path is also of water that falls on the outer slopes of the WRSAs and travels along the surface of the WRSA to the toe as runoff. Water losses were accounted at the surface of the pile prior to infiltration and within the pile as follows; ? water losses from evaporation is represented by a runoff coefficients; and ? water loss to the pile is modeled based on a percentage of volume of waste rock. As each WRSA is saturation flows exiting the pile increase. Flat infiltration is the slowest flow path and creates base flows that maintain flows out of the WRSAs during late summer and early winter periods. The slopes seepage is released more slowly over several days or weeks. While slopes runoff is the fastest flow path creating storm peaks during rainfall events. Results of the total WRSA discharge are a constant slow outflow at the toe with small increases due to precipitation events and the freshet, which is consistent with observations of waste rock drainage. Flows are attenuated using a time delay, which was simulated for each flow path using an Erlang function. The Erlang function refers to a two-parameter Gaussian distribution, where the shape parameter n is an integer. Hydrologically, the parameter n corresponds to the number of hypothetical linear reservoirs (Nash 1957). For the slopes runoff, n = 1 is assumed, which gives an exponential distribution. For the flats infiltration and slope seepage n = 2 is assumed, which gives a typical unit hydrograph shape with a delayed peak flow. The value of the lag parameter for each component was determined through model calibration. |
DS201509-0417 2015 | Palyanov, Y.N., Borzdov, Y.M., Kupriyanov, I.N., Bataleva, Y.V., Khohkhryakov, A.F. | Diamond crystallization from tin-carbon system at HPHT conditions. | Diamond and Related Materials, Vol. 58, pp. 40-45. | Technology | Diamond synthetics |
| Abstract: Diamond crystallization from the tin–carbon system has been studied at 7 GPa and temperatures ranging from 1600 to 1900 °C with reaction times from 1 to 20 h. Both diamond growth on the seed crystals and diamond spontaneous nucleation were established, providing evidence for the catalytic ability of tin. A distinctive feature of the Sn–C system is the existence of a significant induction period preceding diamond spontaneous nucleation. Temperature and kinetics are found to be the main factors governing diamond crystallization process. The minimum parameters of diamond spontaneous nucleation are determined to be 7 GPa, 1700 °C and 20 h. The stable form of diamond growth is octahedron and it does not depend on temperature. Synthesized diamonds contain high concentrations of nitrogen impurities up to about 1600 ppm. |
DS201502-0089 2015 | Palyanov, Y.U., Sokol, A.G., Khokhryakov, A.F., Kruk, A.N. | Conditions of diamond crystallization in kimberlite melt: experimental data. | Russian Geology and Geophysics, Vol. 56, 1-2, pp. 196-210. | Technology | Diamond morphology |
DS201504-0212 2015 | Panero, W.R., Pigott, J.S., Reaman, D.M., Kabbes, J.E., Liu, Z. | Dry ( Mg,Fe) SiO3 perovskite in the Earth's lower mantle. | Journal of Geophysical Research, Vol. 120, 2, pp. 894-908. | Mantle | Perovskite |
DC201501-1632 2014 | Pangolin Diamonds Corporation | Microprobe and drilling results from Malatswe, Botswana. Picroilmenites | Pangolin Diamonds Corporation, Dec. 9, 2p. | Africa, Botswana | News item - press release |
DC201502-1633 2015 | Pangolin Diamonds Corporation | Pangolin discovers a second diamond area, Malatswae, Botswana. | Pangolin Diamonds Corporation, Jan. 13, 2p. | Africa, Botswana | News item - press release |
DC201505-1634 2015 | Pangolin Diamonds Corporation | Pangolin closes $ 404,375 financing for diamond projects in Botswana. | Pangolin Diamond Corporation, Mar. 27, 1p. | Africa, Botswana | News item - press release |
DC201505-1635 2015 | Pangolin Diamonds Corporation | Pangolin receives additional prospecting licences at the Malatswae diamond project, Botswana. | Pangolin Diamond Corporation, Apr. 7, 1p. | Africa, Botswana | News item - press release |
DC201507-1636 2015 | Pangolin Diamonds Corporation | Update for the MAL157 diamond, Malatswae diamond project, Botswana. | Pangolin Diamonds Corporation, June 2, 2p. | Africa, Botswana | News item - press release |
DC201508-1631 2015 | Pangolin Diamonds Corporation | Pangolin appoints Dr. Leon Daniels as President/CEO and new BOD Patrick Harford; premium to market private placement ( up to $500,000) | Pangolin Diamond Corporation, July 9, 1p. | Africa, Botswana | News item - press release |
DC201508-1637 2015 | Pangolin Diamonds Corporation | Pangolin updates Malatswae diamond project, Botswana. | Pangolin Diamond Corporation, June 30, 1p. | Africa, Botswana | News item - press release |
DC201508-1638 2015 | Pangolin Diamonds Corporation | Pangolin receives positive kimberlite indicator analyses for Malatswae diamond project, Botswana. | Pangolin Diamond Corporation, July 15, 2p. | Africa, Botswana | News item - press release |
DC201509-1639 2015 | Pangolin Diamonds Corporation | Update for the Botswana exploration projects - DMS plant and soil sampling. Malatsawe, Rehobeth, Jwaneng South, Machaneng South projects. | Pangolin Diamonds Corporation, July 29, 2p. | Africa, Botswana | News item - press release |
DC201509-1640 2015 | Pangolin Diamonds Corporation | Pangolin receives positive results from ground penetrating at Malatswae diamond project, Botswana. | Pangolin Diamonds Corporation, Aug. 12, 3p. | Africa, Botswana | News item - press release |
DC201510-2359 2015 | Pangolin Diamonds Corporation | Pangolin receives positive results from ground penetrating radar survey at Malatswae diamond project, Botswana. | Pangolin Diamonds Corporation , Sept. 23, 2p. | Africa, Botswana | News item - press release |
DC201511-2401 2015 | Pangolin Diamonds Corporation | Pangolin recovers fifth diamond from Malatswae diamond project, Botswana. | Pangolin Diamonds Corporation, Sept. 29, 2p. | Africa, Botswana | News item - press release |
DC201512-2447 2015 | Pangolin Diamonds Corporation | Pangolin recovers 14 pyrope garnets from Malatswae. | Pangolin Diamonds Corporation, Nov. 3, 1p. | Africa, Botswana | News item - press release |
DC201512-2448 2015 | Pangolin Diamonds Corporation | Pangolin recovers two diamond fragments from Malatswae. | Pangolin Diamonds Corporation, Nov. 16, 1p. | Africa, Botswana | News item - press release |
DC201512-2449 2015 | Pangolin Diamonds Corporation | Pangolin reports pyrope G10 garnets, Malatswae diamond project, Botswana. | Pangolin Diamonds Corporation, Nov. 19, 2p. | Africa, Botswana | News item - press release |
DC201501-1641 2014 | Paragon Diamonds Limited | Paragon Diamonds update on processing plant for Lemphane kimberlite project Lesotho. | Paragon Diamonds Limited, Nov. 25, 2p. | Africa, Lesotho | News item - press release |
DC201503-1642 2015 | Paragon Diamonds Limited | Binding MOU signed for US $ 12 m financing package. Triangle General Trading. | Paragon Diamonds Limited, Jan. 28, 1p. | Africa | News item - press release |
DC201504-1643 2015 | Paragon Diamonds Limited | Update on Lemphane diamond project and placing. | Paragon Diamonds Limited, Mar. 13, 4p. | Africa, Lesotho | News item - press release |
DC201506-1644 2015 | Paragon Diamonds Limited | Mou to acquire Mothae kimberlite diamond project in Lesotho from Lucara. | Paragon Diamonds Limited, May 5, 5p. | Africa, Lesotho | News item - press release |
DC201507-1645 2015 | Paragon Diamonds Limited | Paragon Diamonds confident of Mothae approval ahead of Lesotho trip. | Paragon Diamonds Limited, June 18, 2p. | Africa, Lesotho | News item - press release |
DC201510-2360 2015 | Paragon Diamonds Limited | Positive technical study for Mothae kimberlite project. | Paragon Diamonds Limited, Sept. 15, 2p. | Africa, Lesotho | News item - press release |
DS201503-0166 2015 | Pasava, J., Malec, J., Griffin, W.L., Gonzalez-Jiminez, J.M. | Re-Os isotopic constraints on the source of platinum-group minerals (PGMs) from the Vestrev pyrope rich garnet placer deposit, Bohemian Massif. | Ore Geology Reviews, Vol. 68, pp. 117-1326 | Europe | Garnet mineralogy |
DS201510-1797 2015 | Pashkevich, I.K., Savchenko, A.S., Starostenko, V.I., Sharov, N.V. | A three dimensional geophysical model of the Earth's crust in the central part of the Karelian Craton. | Doklady Earth Sciences, Vol. 463, 2, pp. 808-812. | Russia | Geophysics |
DS201507-0330 2015 | Pavlov, V.E., Shatsilli, A.V. | Place of birth of the Siberian platform. | Doklady Earth Sciences, Vol. 462, 1, pp. 444-448. | Russia | Magmatism |
DS201511-1866 2014 | Payne, C., Bauer, R. | Differing causes of colour in diamonds. | Australian Gemmologist, Vol. 24, 1, pp. 15-16. | Technology | Diamond colour |
DS201501-0025 2015 | Pell, J. | Building the diamond resource at Chidliak, Baffin Island, Nunavut. | PDAC 2015, 1p. Abstract | Canada, Nunavut, Baffin Island | Deposit - Chidliak |
DS201501-0024 2015 | Pell, J., Russell, J.K., Zhang, S. | Kimberlite emplacement temperatures from conodont geothermometry. | Earth and Planetary Science Letters, Vol. 411, pp. 131-141. | Canada, Nunavut, Baffin Island | Deposit - Chidliak |
DS201508-0371 2015 | Pell, R. | Kovdor plans for expansion. | International Mining, July p. 16, 18, 20 | Russia, Kola Peninsula | Deposit - Kovdor |
DC201501-1646 2014 | Peregrine Diamonds Ltd. | Peregrine prepares for Chidliak development program. Production in phases CH-6, CH-7 and CH-44 first phase. | Peregrine Diamonds Limited, Dec. 7, 4p. | Canada, Nunavut, Baffin Island | News item - press release |
DC201502-1650 2014 | Peregrine Diamonds Ltd. | Peregrine arranges $ 2.19 million private placement. | Peregrine Diamonds Limited, Dec. 22, 1p. | Canada, Nunavut, Baffin Island | News item - press release |
DC201502-1651 2014 | Peregrine Diamonds Ltd. | Peregrine completes $ 2.19 million private placement. | Peregrine Diamonds Limited, Dec. 30, 1p. | Canada, Nunavut, Baffin Island | News item - press release |
DC201502-1652 2015 | Peregrine Diamonds Ltd. | Peregrine reports 15% increase in CH-6 kimberlite inferred diamond resource to 8.57 million carats and significant kimberlite tonnage estimate increases for CH-6, CH-7 and CH-44. | Peregrine Diamonds Ltd., Jan. 26, 6p. | Canada, Nunavut, Baffin Island | News item - press release |
DC201503-1653 2015 | Peregrine Diamonds Ltd. | Peregrine forms, staffs new subsidiary. Peregrine Exploration Ltd. | Peregrine Diamonds Ltd., Feb. 12, 2p. | Canada, Nunavut, Northwest Territories | News item - press release |
DC201504-1654 2015 | Peregrine Diamonds Ltd. | Peregrine Files NI 43-101 technical report for Chidliak. | Peregrine Diamonds Ltd., Feb. 24, 3p. | Canada, Nunavut, Baffin Island | News item - press release |
DC201504-1655 2015 | Peregrine Diamonds Ltd. | Peregrine files updated technical report for Chidliak project. | Peregrine Diamonds Ltd., Feb. 24, 1p. | Canada, Nunavut, Baffin Island | News item - press release |
DC201504-1656 2015 | Peregrine Diamonds Ltd. | Peregrine identifies new zone with high diamond counts at Chidliak CH-7 kimberlite pipe. | Peregrine Diamonds Ltd., Mar. 10, 5p. | Canada, Nunavut, Baffin Island | News item - press release |
DC201504-1657 2015 | Peregrine Diamonds Ltd. | Peregrine begins bulk sample drilling at Chidliak. Update on 2015 diamond resource development program. | Peregrine Diamonds Ltd., Mar. 23, 2p. | Canada, Nunavut, Baffin Island | News item - press release |
DC201504-1658 2015 | Peregrine Diamonds Ltd. | Peregrine Diamonds announces transfer of assets to Peregrine exploration and commencement of exploration initiatives ( including extensive database) | Peregrine Diamonds Ltd., Mar. 24, 3p. | Canada, Northwest Territories | News item - press release |
DC201505-1659 2015 | Peregrine Diamonds Ltd. | Peregrine to acquire Diamexstrat Botswana. 8 highly prospective licences. | Peregrine Diamonds Ltd., Mar. 30, 3p. | Africa, Botswana | News item - press release |
DC201505-1660 2015 | Peregrine Diamonds Ltd. | Peregrine receives $ 11.85 million from warrant exercise. | Peregrine Diamonds Ltd., Apr. 7, 1p. | Canada, Nunavut | News item - press release |
DC201505-1661 2015 | Peregrine Diamonds Ltd. | Peregrine provides update on 2015 diamond resource development program. | Peregrine Diamonds Ltd., Apr. 23, 2p. | Canada, Nunavut | News item - press release |
DC201506-1662 2015 | Peregrine Diamonds Ltd. | Peregrine announces completion of RC drilling portion of 2015 diamond resource development at Chidliak. CH-7 | Peregrine Diamonds Ltd., May 14, 4p. | Canada, Nunavut, Baffin Island | News item - press release |
DC201508-1647 2015 | Peregrine Diamonds Ltd. | Peregrine closes acquisition of Diamexstrat. Completes Botswana transaction and commences 2015 Botswana exploration program. DES U.K. | Peregrine Diamonds Limited, July 14, 1p. | Africa, Botswana | News item - press release |
DC201508-1648 2015 | Peregrine Diamonds Ltd. | Peregrine provides Chidliak bulk sample update and commences summer 2015 diamond resource development program. | Peregrine Diamonds Limited, July 21, 3p. | Canada, Nunavut, Baffin Island | News item - press release |
DC201509-1649 2015 | Peregrine Diamonds Ltd. | Peregrine Diamonds may benefit from new Iqaluit port. | Peregrine Diamonds Limited, July 31, 1p. | Canada, Nunavut | News item - press release |
DC201510-2361 2015 | Peregrine Diamonds Ltd. | Peregrine completes Field work program at Chidliak. | Peregrine Diamonds Limited, Sept. 9, 3p. | Canada, Nunavut, Baffin Island | News item - press release |
DC201511-2402 2015 | Peregrine Diamonds Ltd. | Peregrine to commence drilling kimberlite targets in Botswana. Moralane | Peregrine Diamonds Ltd., Oct. 22, 2p. | Africa, Botswana | News item - press release |
DC201512-2450 2015 | Peregrine Diamonds Ltd. | Peregrine dat a suggest Chidliak CH-7, CH-6 increases. New microdiamond dat a supports increased diamond content at CH-7 and the potential to add 2.5 to 3.1 million carats at CH-6. | Peregrine Diamonds Limited, Nov. 17, 8p. | Canada, Nunavut, Baffin Island | News item - press release |
DC201512-2451 2015 | Peregrine Diamonds Ltd. | Peregrine Diamonds arranges $ 7 million rights offering. | Peregrine Diamonds Limited, Nov. 19, 2p. | Africa, Botswana | News item - press release |
DS201507-0331 2015 | Persikov, E.S., Bukhtiyarov, P.G., Sokol, A.G. | Change in the viscosity of kimberlite and basaltic magmas during their origin and evolution ( prediction). | Russian Geology and Geophysics, Vol. 56, pp. 885-892. | Canada, Northwest Territories, Russia | Deposit - Jericho, Udachnaya |
DC201506-1666 2015 | Petra Diamonds Limited | Diamond miners agree to form a diamond producers association. Alrosa, De Beers, Rio Tinto, Dominion, Lucara, Petra, Gem Diamonds | Petra Diamonds Limited, May 28, 1p. | Global | News item - press release |
DC201507-1663 2015 | Petra Diamonds Limited | Diamond miners agree to form a diamond producers association. | Petra Diamonds Limited, May 28, 1p. | Global | News item - press release |
DC201507-1664 2015 | Petra Diamonds Limited | FY 2015 - market update ( diluted ore) | Petra Diamonds Limited, June 12, 1p. | Africa, South Africa | News item - press release |
DC201508-1665 2015 | Petra Diamonds Limited | Trading update for the year ended 30 June 2015 FY 2016 guidance update. | Petra Diamonds Limited, July 27, 2p. | Africa, South Africa | News item - press release |
DC201510-2362 2015 | Petra Diamonds Limited | Preliminary results announcement for the year ended 30 June 2015. Declaration of maiden dividend. | Petra Diamonds Limited, Sept. 18, 4p. | Africa, South Africa | News item - press release |
DC201512-2452 2015 | Petra Diamonds Limited | Trading update - Q1 FY 2016 production and sales report. | Petra Diamonds Limited, Oct. 28, 3p. | Africa, South Africa | News item - press release |
DC201512-2453 2015 | Petra Diamonds Limited | Recovery of 23 carat pink diamond at Williamson. | Petra Diamonds Limited, Nov. 27, 1p. | Africa, Tanzania | News item - press release |
DS201506-0290 2015 | Petra Diamonds Limited | Cullinan: The world's most celebrated diamond mine. | Petra Diamonds Limited, petradiamonds.com March 20 ppt | Africa, South Africa | Deposit - Cullinan - history |
DS201502-0090 2015 | Petrus, J.A., Ames, D.E., Kamber, B.S. | On the track of the elusive Sudbury impact: geochemical evidence for a chondrite or comet bolide. | Terra Nova, Vol. 27, 1, pp. 9-20. | Canada, Ontario | Meteorite |
DS201506-0291 2015 | Phani, P.R.C. | Area selection for diamond exploration based on geological and morphostructural set-up: examples from Wajrakarur kimberlite field, India. | Journal of Advanced chemical sciences, Vol. 1, 3, pp. 102-106. | India | Deposit - Wajrakarur |
DC201511-2403 2015 | Phosphate Australia Limited | Blin a diamond project, Ellendale WA: acquisition. Alluvials and lamproite pipes | Phosphate Australia Limited, Oct. 9, 21p. | Australia | News item - press release |
DS201511-1867 2015 | Pilet, S. | Generation of low-silica alkaline lavas: petrological constraints, models, and thermal implications. | Geological Society of America Special Paper, No. 514, pp. SPE14-17. | Mantle | Melting, metasomatism |
| Abstract: Various hypotheses for the origin of alkaline sodic mafic magmas have been proposed. This diversity of models is mainly related to the various constraints used to develop them. The goal of this paper is to test these different models using petrological and geochemical constraints in an attempt to understand why alkaline sodic rocks are so similar even while their environment of formation varies from oceanic to continental rift. Incompatible trace-element contents of alkaline basalts from ocean islands and continents show that the sources of these rocks are more enriched than primitive mantle. A fundamental question then is how the sources of alkaline rocks acquire these trace-element enrichments. Recycled oceanic crust, with or without sediment, is often invoked as a source component of alkaline magmas to account for their trace-element and isotopic characteristics. However, the fact that melting of oceanic crust produces silica-rich liquids seems to exclude the direct melting of eclogite derived from mid-ocean-ridge basalt to produce alkaline lavas. Recycling oceanic crust in the source of alkaline magma requires either (1) that the mantle "digests" this component producing metasomatized CO2-rich peridotitic sources or (2) that low-degree melt from recycled oceanic crust reacts with peridotite in the presence of CO2, producing low-silica alkaline melt by olivine dissolution and orthopyroxene precipitation. These two hypotheses are plausible in terms of major elements. However, they have specific implications about the type and proportion of recycled lithologies present in the asthenosphere to explain the specific trace-element pattern of intraplate alkaline lavas. A third hypothesis for the formation of alkaline magmas is the melting of metasomatized lithosphere. In this model, the major- and trace-element signature of alkaline magma is not controlled by the asthenospheric source (i.e., the amount of oceanic crust or CO2 present in the asthenosphere), but by the petrological process that controls the percolation and differentiation of low-degree asthenospheric melts across the lithosphere. This process forms amphibole-bearing metasomatic veins that are a candidate source of alkaline rocks. This hypothesis offers an explanation for the generation of the Na-alkaline lavas with similar major- and trace-element composition that are observed worldwide and for the generation of K- and Na-alkaline magma observed in continental settings. This hypothesis requires the formation of significant amounts of metasomatic veins within the lithosphere. Qualitative analyses of the thermal implication of the potential models for the generation of alkaline rocks demonstrate that such magma requires low potential temperature (Tp: 1320 °C to 1350 °C). If temperatures are higher, melting of the convecting mantle will erase any signature of low-degree melts produced from fertile mantle lithologies. This analysis suggests that a role for hot thermal plumes in the generation of intraplate volcanoes dominated by alkaline magmas is unrealistic. |
DS201506-0292 2015 | Pinti, D., Ishida, A., Takahata, N., Sano, Y. | Carbon isotopes in a Juin a diamond with carbonate inclusions. | Japan Geoscience Union Meeting, SCG16-05 May 28 abstract | South America, Brazil | Deposit - Juina |
DS201506-0293 2015 | Piper | The Precambrian supercontinent Palaeopangaea: two billion years of quasi-integrity and an appraisal of geological evidence. | International Geology Review, Vol. 57, 11-12, pp. 1389-1417. | Global | Paleopangea |
DS201503-0167 2015 | Piper, J.D.A. | Supercontinent integrity between 0.8 and 0.6 Ga: the nemesis of Rodinia? | Geological Society of London Special Publication: Continent formation through time., No. 389, pp. 69-81. | Mantle | Rodinia |
DS201503-0168 2015 | Pirajno, F. | Intracontinental anorogenic alkaline magmatism and carbonatites, associated mineral systems and the mantle plume connection. Brandberg, Erongo, Parana-Etendeka, Kruidfontein, Goudini | Gondwana Research, Vol. 27, 3, pp. 1181-1216. | Africa, East Africa, Namibia, South Africa, China, Australia | Carbonatite |
DS201510-1798 2015 | Pirard, C., Hermann, J. | Focused fluid transfer through the mantle above subduction zones. | Geology, Vol. 43, 10, pp. 915-918. | Mantle | Subduction |
| Abstract: Volcanic arcs above subduction zones are enriched in volatiles and fluid-mobile elements with respect to mid-oceanic ridge basalts. There is general consensus that this particular subduction zone signature is generated by fluid-induced extraction of these elements from subducted oceanic crust and its sedimentary cover. However, how these fluids are transferred through the mantle wedge to the locus of partial melting and what modification the fluids will experience is unresolved. Here we investigate the interaction of slab fluids with the mantle wedge through a series of high-pressure experiments. We explore two end-member processes of focused and porous reactive flow of hydrous slab melts through the mantle. Transfer by porous flow leads to the formation of hydrous minerals that sequester fluid-mobile elements and residual fluids characterized by trace element patterns inconsistent with typical arc lavas. In contrast, no hydrous minerals are formed in the reaction zone of experiments mimicking focused flow, and the typical trace element signature acquired during fluid extraction from the slab is preserved, indicating that this is an efficient process for element transfer through the mantle wedge. |
DS201501-0026 2015 | Pittari, A., Cas, R.A.F., Lefebvre, N., Kurszlaukis, S. | Alteration styles in the Orion Central Volcanic Complex, Fort a la Corne kimberlite field, Saskatchewan, and their effects on primary volcaniclastic textures: implications for facies mapping and diamond exploration. | Economic Geology, Vol. 110, pp. 146-171. | Canada, Saskatchewan | Deposit - Orion Central Volcanics |
DS201509-0419 2015 | Podvysotski, V.T., Bashinsli, S.I. | A new dat a about Cretaceous Diamondiferous conglomerates in Juin a Province ( Mato Grosso state, Brazil). | Vestnik VGU, Seria Geologia, IN RUSSIAN, No. 2, pp. 73-76. | South America, Brazil, Mato Grosso | Deposit - Juina area |
DS201502-0091 2015 | Poikilenko, N.P., Agashev, A.M., Litasov, K.D., Pokhilenko, L.N. | Carbonatite metasomatism of peridotite lithospheric mantle: implications for diamond formation and carbonatite-kimberlite magmatism. | Russian Geology and Geophysics, Vol. 56, 1, pp. 280-295. | Mantle | Carbonatite |
DS201503-0169 2015 | Poirier, G. | Renard: Quebec's first diamond mine. | PDAC 2015, Abstract, 1p. | Canada, Quebec | Deposit - Renard |
DS201512-1958 2015 | Poitras, S.P. | A geochemical study of diamond indicator minerals from the NWT interior platform. | 43rd Annual Yellowknife Geoscience Forum Abstracts, abstract p. 86. | Canada, Northwest Territories | Geochemistry |
| Abstract: The Central Mackenzie Valley (CMV) area of the Northwest Territories (NWT) comprises a Phanerozoic sedimentary basin that lies between the western margin of the Slave craton and the Cordillera. Although the region is considerably outside the bounds of the exposed Slave craton, both LITHOPROBE and more recent regional-scale surface wave studies (e.g., Priestley and McKenzie, 2006) indicate the likely presence of lithospheric mantle extending into the diamond stability field. Recent work conducted by Olivut Resources Ltd. led to the discovery of 29 kimberlites in the CMV. However, the indicator mineral chemistry of discovered kimberlites does not appear to be a good match (www.olivut.ca) with those during regional till and stream sediment sampling by the Geologic Survey of Canada (GSC) and Northwest Territories Geologic Survey (NTGS) in August 2003 and July 2005. We present new geochemical data on the regional indicator minerals with the aim of obtaining geotherm and depth of mantle sampling constraints on those indicator minerals discovered to date. A statistical evaluation of the data will compare the similarities to indicator mineral chemistry with parts of the Slave craton to evaluate whether the CMV indicators may ultimately be derived from that region. In total 3600 kimberlite indicator mineral grains were picked from the 0.25-2.0 mm size fractions. Peridotitic garnet grains dominate (46%), followed by magnesium ilmenite (26%), with decreasing individual proportions >15% of chromite, low-chrome diopside, olivine, chrome-diopside and eclogitic garnet. A sub-sample of these grains (3143) were analysed by EPMA. Garnet grains classify (after Grütter et al., 2004) as 1015 (62.1%) G9, 270 (16.5%) G11, 113 (6.9%) G10, 103 (6.3%) G12, 57 (3.5%) G1, 46 (2.8%) G10D, and the remaining 31 (1.9%) as G0, G3, G3D, G4, and G5. A sub-set of garnet grains (~700) were selected for LA-ICP-MS trace element analysis. Of the grains selected 74% G9, 14% G10 (and G10D), and 8% G11, with only 4% G12 and G0 (Grütter et al., 2004). Nickel concentrations from these grains range from 2.6-168.2 ppm, with the majority (>80%) between 20-100 ppm, yielding TNi (Canil, 1999) values ranging from 643-1348°C, with the majority between ~1000-1200°C. Using a central Slave craton geothermal gradient (Hasterok and Chapman, 2011), equilibration pressures for these garnet grains range from 20-80 kbars with the majority between 40-60 kbars (120-185 km). Preliminary analysis has 581 (81%) of the erupted peridotitic mantle garnet grains plotting within the diamond stability field (Kennedy and Kennedy, 1976). Of the 128 clinopyroxene grains analysed, only a few represent garnet peridotite (lherzolite) facies KIM clinopyroxene grains following compositional screening. Thermobarometry of these grains (Nimis and Taylor, 2000), assuming they were all derived from the same lithospheric section, yields P-T arrays identical to the central Slave geotherm that was 220 km thick at the time of eruption. These results are encouraging for diamond exploration. We thank Overburden Drilling Management Ltd. for grain picking and recovery of the small diamond, SGS Lakefield Research for mounting grains, and the GSC for probing of the grains. |
DS201509-0420 2015 | Poli, S. | Carbon mobilized at shallow depths in subduction zones by carbonatitic liquids. | Nature Geoscience, Vol. 8, pp. 633-636. | Mantle | Carbonatite |
| Abstract: More than half a gigaton of CO2 is subducted into Earth’s interior each year1. At least 40% of this CO2 is returned to the atmosphere by arc volcanism2, 3, 4. Processes that are known to release carbon from subducting slabs—decarbonation or carbonate dissolution in fluids—can account for only a portion of the CO2 released at arc volcanoes5. Carbonatitic liquids may form from the subducting crust, but are thought to form only at very high temperatures. Melting of carbonated rocks could restrict the subduction of carbon into the deeper Earth. However, the behaviour of such rock types in subduction zones is unclear. Here I use laboratory experiments to show that calcium-rich hydrous carbonatitic liquids can form at temperatures as low as 870 to 900 °C, which corresponds to shallow depths of just 120 km beneath subduction zone arcs, in warm thermal regimes. I find that water strongly depresses the solidus for hydrous carbonate gabbro and limestone rocks, creating carbonatitic liquids that efficiently scavenge volatile elements, calcium and silicon, from the slab. These extremely mobile and reactive liquids are expected to percolate into the mantle wedge, and create a CO2 source for subduction zone magmatism. Carbonatitic liquids thus provide a potentially significant pathway for carbon recycling at shallow depths beneath arcs. |
DS201504-0213 2015 | Prescher, C., Dubrovinsky, L., Bykova, E., Kupenko, I., Glazyrin, K. | High Poisson's ration of Earth's inner core explained by carbon alloying. | Nature Geoscience, Vol. 8, 3, pp. 220-223. | Mantle | Core, carbon |
DS201508-0372 2015 | Presser, J. | Kalahari Craton, Yakutia craton area - seismic tomography. | [email protected], 3 images dvs inverted x-1 pdfs available | Africa | Map - kimberlites |
DS201509-0421 2015 | Presser, J. | Mantle tomography - Cullinan | [email protected], pdf file | Africa, South Africa | Deposit - Cullinan |
DS201509-0422 2015 | Presser, J. | Mantle tomography Itapoti diamond area | [email protected], pdf file | South America, Paraguay | Geophysics - seismics |
DS201511-1868 2015 | Presser, J. | Orapa - example using seismics | [email protected], 1p. Available | Africa, Botswana | Geophysics - Orapa |
DS201511-1869 2015 | Presser, J. | International Mir - example using seismics | [email protected], 1p. Available | Russia | Geophysics - Mir |
DS201512-1959 2015 | Presser, J. | Botswana showing pipe locations, | [email protected], 1 pdf available | Africa, Botswana | Geophysics - pipes |
DM201503-2480 2015 | Proactive Investors | DiamondCorp's progress on underground mine lauded by brokers. Lace | proactiveinvestores.co.uk, Jan. 28, 1/2p. | Africa, South Africa | News item - DiamondCorp |
DM201504-0925 2015 | Purcell, W. | Sandstorm Gold Ltd. Paid $52.5 million US to Iamgold Corp. for its 1 % gross proceeds royalty on Diavik mine. ( Iamgold has been receiving $ 7 or 8 million an year from it) | Stockwatch Summary for March 23, Mar. 24, 1/4p. | Canada, Northwest Territories | News item - Diavik |
DM201506-2472 2015 | Purcell, W. | 92 Resources Corp. intends to acquire "certain rights" om a diamond prospect in Finland. | Stockwatch Diamonds & Specialty Minerals, Summary April 27, 2p. | Europe, Finland | News item - 92 Resources |
DC201501-1669 2014 | Pure Grown Diamonds | Pure Grown Diamonds announces a scientific breakthrough .. Largest laboratory-cultivated white diamond 3.04 carats. | Pure Grown Diamonds, Dec. 8, 1p. | Technology | News item - press release |
DC201508-1670 2015 | Pure Grown Diamonds | Pure Grown Diamonds wins 2015 Eco-Excellence award. | Pure Grown Diamonds, July 23, 1p. | Technology | News item - press release |
DS201510-1799 2014 | Pushkarev, Y.D. | Fundamental problems of the Earth evolution and the nature of D" layer as one of them. | Deep-seated magmatism, its sources and plumes, Proceedings of XIII International Workshop held 2014., Vol. 2014, pp. 104-123. | Mantle | Geodynamics |
DM201504-0926 2014 | Quenneville, G. | They're back: History of diamond exploration - who will find diamond mine no. 5? | Up Here Business Magazine, November pp. 23-26,28-30, 32, 38, 50. | Canada, Northwest Territories, Nunavut | News item - history |
DS201507-0332 2015 | Quere, S., Lowman, S., Arkani-Hamed, J.P. | Subcontinental sinking slab remnants in a spherical geometry mantle model. | Journal of Geophysical Research, Vol. 118, 4, pp. 1760-1777. | Mantle | Subduction |
DC201512-2454 2015 | Raiman Rocks | Rare fancy pink diamond and fancy blue diamond unveiled from the "rare diamonds of the world" collection. Pink Flame Type 11a and Ocean Blue… Type 11b | RaimanRocks.com , Nov. 10, 1p. | Technology | News item - diamond notable |
DS201503-0170 2015 | Rakhmanova, M.I., Nadolinny, V.A., Yuryeva, O.P., Pokhilenko, N.P., Logvinova, A.M. | Pecularities of nitrogen impurity aggregation in diamonds from the Sytykanskaya pipe, Yakutia. | European Journal of Mineralogy, Vol. 27, pp. 51-56. | Russia, Yakutia | Deposit - Sytykanskaya |
DM201501-0927 2014 | Rapaport Magazine | Botswana's diamond landscape. Trading centre, goal of jewelery manufacturing, expanding Jwaneng, rough selling, ODC | Rapaport Magazine, December, 5p. | Africa, Botswana | News item - ODC |
DM201501-0928 2014 | Rapaport Magazine | Designing women.. History of women paving the way forward from Victorian era … Maker & Muse: women and Early Twentieth Century Art Jewelry exhibit in Chicago opens Feb. 14, 2015. | Rapaport Magazine, December, 3p. | Global | News item - history |
DM201501-0929 2014 | Rapaport Magazine | Liquidity concerns… diamond markets, stable US demand, rough trends, | Rapaport Magazine, December, 3p. | Global | News item - economics |
DM201501-0930 2014 | Rapaport Magazine | A more accessible De Beers. Simpler, more stringent contract, right goods in the right hands, De Beers Botswana structure, sight and fees | Rapaport Magazine, December, 4p. | Global | News item - De Beers |
DM201510-2057 2015 | Rapaport Magazine | Udachny update .. Moves underground. | Rapaport Magazine, Sept. 3p. | Russia | News item - Udachny |
DM201510-2058 2015 | Rapaport Magazine | Diamond dream East vs West. Markets and marketing traditions. | Rapaport Magazine, Sept. 5p. | Global | News item - markets |
DM201511-2154 2015 | Rapaport Magazine | Kimberley Process: where is it now? | Rapaport Magazine, Sept. 3p. | Global | News item - KPCS |
DM201511-2155 2015 | Rapaport Magazine | 100 carat diamond club. History and comments on notable diamonds. | Rapaport Magazine, Oct. 13, 6p. | Global | News item - diamond notable |
DS201509-0423 2014 | Ratheesh-Kumar, R.T., Ishwar-Kumar, C., Windley, B., Razakamanana, T., Nair, R.R., Sajeev, K. | India-Madagascar paleo-fit based on flexural isostasy of their rifted margins. | Gondwana Research, Vol. 28, 2, pp. 581-600. | India, Africa, Madagascar | Tectonics |
| Abstract: The present study contributes new constraints on, and definitions of, the reconstructed plate margins of India and Madagascar based on flexural isostasy along the Western Continental Margin of India (WCMI) and the Eastern Continental Margin of Madagascar (ECMM). We have estimated the nature of isostasy and crustal geometry along the two margins, and have examined their possible conjugate structure. Here we utilize elastic thickness (Te) and Moho depth data as the primary basis for the correlation of these passive margins. We employ the flexure inversion technique that operates in spatial domain in order to estimate the spatial variation of effective elastic thickness. Gravity inversion and flexure inversion techniques are used to estimate the configuration of the Moho/Crust-Mantle Interface that reveals regional correlations with the elastic thickness variations. These results correlate well with the continental and oceanic segments of the Indian and African plates. The present study has found a linear zone of anomalously low-Te (1-5 km) along the WCMI (~1680 km), which correlates well with the low-Te patterns obtained all along the ECMM. We suggest that the low-Te zones along the WCMI and ECMM represent paleo-rift inception points of lithosphere thermally and mechanically weakened by the combined effects of the Marion hotspot and lithospheric extension due to rifting. We have produced an India-Madagascar paleo-fit representing the initial phase of separation based on the Te estimates of the rifted conjugate margins, which is confirmed by a close-fit correlation of Moho geometry and bathymetry of the shelf margins. The matching of tectonic lineaments, lithologies and geochronological belts between India and Madagascar provide an additional support for the present plate reconstruction. |
DS201501-0027 2015 | Read, G. | Star-Orion South diamond project: optimizing a feasibility study. | PDAC 2015, 1p. Abstract | Canada, Saskatchewan | Deposit - Star-Orion South |
DS201504-0214 2010 | Reidel, F., Dehler, M. | Recovery of unliberated diamonds by x-ray transmission sorting. Earlier paper with size range +8mm | The South African Institute of Mining and Metallurgy, pp. 193-201. | Technology | Diamond recovery |
DS201509-0424 2015 | Renfro | Digital photomicrography for gemologists. | Gems & Gemology, Summer pp. 144-159. | Technology | Photomicrography |
| Abstract: Until recently, film was the preferred medium used for capturing images through the microscope, primarily due to resolution limitations of digital-format cameras. The image quality that can now be achieved by digital cameras is equal, and in many ways superior, to the quality offered by film. Digital photomicrography allows gemologists the opportunity to instantly see the resultant images, which can then be adjusted with image-refining software so that they represent their subject as realistically as possible. This article offers examples of some basic techniques and tips on the application of digital processing to get the most out of photomicrographs. |
DS201511-1870 2015 | Renfro, N. | The application of differential interference contrast microscopy to gemmology. | Journal of Gemmology, Vol. 34, 7, pp. 616-622. | Technology | Luminescence |
DC201510-2363 2015 | Republic of Mining | De Beers and Attawapiskat .. After the Last River screens at Bay Street Film Festival in Thunder Bay. Video on website republicofmining.com | CBC News , Sept. 10, 1p. | Canada, Ontario | News item - Victor |
DM201512-2262 2015 | Republic of Mining | 10 billionaires and Leonardo DiCaprio just invested in a start up that claims it can grow hundreds of real diamonds in 2 weeks. Diamond Foundry | business insider.com, Nov. 11, 2p. | Technology | News item - synthetics |
DM201512-2263 2015 | Republic of Mining | In diamond city, slowdown is not forever - Surat. | TimesofIndia.com, Nov. 21, 1p. | India | News item - Surat |
DM201512-2264 2015 | Republic of Mining | Botswana explores a future without sparklers. | Businessdaylive.co.za, Nov. 23, 1p. | Africa, Botswana | News item - economics |
DM201512-2265 2015 | Republic of Mining | Rough diamond bubble bust ( Part 2) M. Rapaport. | Mineweb.com, Nov. 25, 1p. | Global | News item - rough markets |
DM201508-2473 2015 | Research and Markets | Analyzing the major diamond mines worldwide 2015. In depth 29 mines analyzed. | research and markets.com, July $ 750.00 a copy | Global | News item - mines |
DM201510-2059 2015 | Resource Clips | Birks unveils the biggest diamond ever mined in Canada. North Star 15.1 carat. | Resourceclips.com, Sept. 10, 1p. | Canada, Northwest Territories | News item - North Star |
DM201511-2156 2015 | Resource Clips | Stornoway expands resources while building Quebec's first diamond mine. | Resource Clips, Sept. 29, 3p. | Canada, Quebec | News item - Stornoway |
DM201511-2157 2015 | Resource Clips | Kimberley Process indicted. Tougher measures needed to end conflict diamond trade, says Amnesty International. | Resource Clips, Sept. 30, 3p. | Africa, Central African Republic | News item - KP |
DM201501-0931 2014 | Reuters | Financing and marketing needed to spur diamond market growth - Bain. | Reuters, Dec. 9, 1/2p. | Global | News item - Bain |
DM201502-0932 2014 | Reuters | Chin a challenges India's polished diamond throne. Chin a getting rough from Africa. | Reuters, Dec. 25, 1p. | China, India | News item - polishing |
DM201503-0933 2015 | Reuters | Russian diamond miner Alrosa Q4 output up 8 % q/q | Reuters, Jan. 29, 1/4p. | Russia | News item - Alrosa |
DM201503-0934 2015 | Reuters | Rio Tinto may close Murowa diamond mine in Zimbabwe. Citing the regime of taxes announced by government. | Reuters, Jan. 30, 1p. | Africa, Zimbabwe | News item - Rio Tinto |
DM201503-0935 2015 | Reuters | Endiama to re-open idle mines Shiri Sangamina, Camafuca, Camazambo. | Reuters, Jan. 16, 1/2p. | Africa, Angola | News item - Endiama |
DM201503-0936 2015 | Reuters | De Beers diamond division becoming Anglo American's crown jewel. | Reuters, Feb. 13, 1p. | Global | News item - De Beers |
DM201510-2061 2015 | Reuters | Cameroon involved in Central Africa 'blood diamond' trade: U.N. experts - by Louis Charanneau . | Republic of Mining blog, Sept. 2, 1p. | Africa, Central African Republic | News item - CSR |
DM201512-2266 2015 | Reuters | Once in a blue moon diamond could fetch up to $ 55 million Sotheby's 12.03 carat ( Culli nan mine) | Reuters, Nov. 4, 2p. | Africa, South Africa | News item - diamond notable |
DM201512-2267 2015 | Reuters | Pink diamond nets $ 28.55 mln in healthy stone market - Christie's. The Sweet Josephine bought by Chinese client in Hong Kong. | Reuters, Nov. 10, 1/4p. | Technology | News item - diamond notable |
DM201512-2268 2015 | Reuters | The extremely rare and flawless "Blue Moon Diamond" sold for $48.4 million | Reuters, Nov. 11, 1p. | Technology | News item - diamond notable |
DM201512-2269 2015 | Reuters | Brazil's Odebrecht to sell assets for investment capital ( possible stake in diamond mine in Africa). | Reuters, Nov. 18, 1p. | Africa | News item - Odebrecht |
DM201512-2270 2015 | Reuters | Rough diamond prices need to fall - Rapaport | Reuters, Nov. 26, 1p. | Global | News item - prices |
DS201512-1960 2015 | Reutsky, V., Borzdov, Y., Palyanov, Y., Sokol, A., Izokh, O. | Carbon isotope fractionation during experimental crystallization of diamond from carbonate fluid at mantle conditions. | Contributions to Mineralogy and Petrology, Vol. 170, pp. 41- | Mantle | HPHT |
| Abstract: We report first results of a systematic study of carbon isotope fractionation in a carbonate fluid system under mantle PT conditions. The system models a diamond-forming alkaline carbonate fluid using pure sodium oxalate (Na2C2O4) as the starting material, which decomposes to carbonate, CO2 and elementary carbon (graphite and diamond) involving a single source of carbon following the reaction 2Na2C2O4 ? 2Na2CO3 + CO2 + C. Near-liquidus behaviour of carbonate was observed at 1300 °C and 6.3 GPa. The experimentally determined isotope fractionation between the components of the system in the temperature range from 1300 to 1700 °C at 6.3 and 7.5 GPa fit the theoretical expectations well. Carbon isotope fractionation associated with diamond crystallisation from the carbonate fluid at 7.5 GPa decreases with an increase in temperature from 2.7 to 1.6 ‰. This trend corresponds to the function ?Carbonate fluid-Diamond = 7.38 × 106 T?2. |
DS201502-0092 2015 | Reutsky, V.N., Palyanov, Yu.N., Borzdov, Yu.M., Sokol, A.G. | Isotope fractionation of carbon during diamond cystallization in model systems. | Russian Geology and Geophysics, Vol. 56, 1-2, pp. 239-244. | Technology | Diamond morphology |
DS201505-0236 2015 | Rey, P.F. | The geodynamics of mantle melting. | Geology, Vol. 43, 4, pp. 367-368. | Mantle | Melting |
DS201508-0373 2015 | Robert, F. | Relevance and importance of research in mineral exploration. | SEG Newsletter, No. 102, July, p. 7. | Technology | Not specific to diamonds but interesting reading! |
DS201503-0171 2015 | Roberts, N.M.W., Spencer, C.J. | The zircon archives of continent formation through time. | Geological Society of London Special Publication: Continent formation through time., No. 389, pp. 197-225. | Mantle | Geochronology |
DS201503-0172 2015 | Roberts, N.M.W., Van Kranendonk, J., Parman, S., Clift, P.D. | Continent formation through time. | Geological Society of London Special Publication: Continent formation through time., No. 389, pp. 1-16. | Global | Geotectonics |
DS201502-0093 2014 | Robinson, P.T., Trumbull, R.B., Schmitt, A., Yang, J-S., Li, J-W., Zhou, M-F., Erzinger, J., Dare, S., Xiong, F. | The origin and significance of crustal minerals in ophiolitic chromitites and peridotites. | Gondwana Research, Vol. 27 2, pp. 486-506. | | Peridotite |
DC201501-1672 2014 | Rockwell Diamonds Inc. | Rockwell reports tenth successive quarterly imrovement and record diamond production and sales revenue. | Rockwell Diamonds Inc., Dec. 15, 2p. | Africa, South Africa | News item - press release |
DC201502-1673 2015 | Rockwell Diamonds Inc. | Rockwell announces an acquisition which will expand its operating and resource footprint in the Middle Orange River region of South Africa. Bondeo 140 CC | Rockwell Diamonds Inc., Jan. 6, 2p. | Africa, South Africa | News item - press release |
DC201502-1674 2015 | Rockwell Diamonds Inc. | Rockwell delivers increase and lower operating costs in Q3 due to higher volumes processed but lower grades lead to rationalization of Saxendrift Hill Complex and focus on Niewejaarskraal expansion ahead of acquisition of contiguous MOR alluvial diamond a | Rockwell Diamonds Inc., Jan. 13, 5p. | Africa, South Africa | News item - press release |
DC201504-1675 2015 | Rockwell Diamonds Inc. | Rockwell issuses update on resource estimates and other developments in the Middle Orange River diamond fields. | Rockwell Diamonds Inc., Mar. 9, 9p. | Africa, South Africa | News item - press release |
DC201505-1676 2015 | Rockwell Diamonds Inc. | Rockwell sells non-core Tirisano project for a cash consideration of $ 6.3 million and provides an update on its Middle Orange River exploration activities. The Consortium ( operating team) | Rockwell Diamonds Inc., Mar. 30, 2p. | Africa, South Africa | News item - press release |
DC201505-1677 2015 | Rockwell Diamonds Inc. | Rockwell announces its quarterly production and sales update for the three months ending Feb. 28, 2015. MOR, Saxebdrift, Niewejaarskraal, Tirisano, Kwartelspan | Rockwell Diamonds Inc., Apr. 20, 7p. | Africa, South Africa | News item - press release |
DC201506-1678 2015 | Rockwell Diamonds Inc. | Rockwell looks to conclude its recently announced acquisition of Remhoogte Holsloot operation. | Rockwell Diamonds Inc., May 27, 1p. | Africa, South Africa | News item - press release |
DC201507-1679 2015 | Rockwell Diamonds Inc. | Rockwell shelves equity finance for Remhoogte… in favour of bridging finance. Diacore and Bristow | Miningmx.com, May 29, 1p. | Africa, South Africa | News item - Rockwell |
DC201507-1680 2015 | Rockwell Diamonds Inc. | Announces results for the three and twelve months ended February 28, 2015. | Rockwell Diamonds Inc., May 28, 1p. | Africa, South Africa | News item - press release |
DC201507-1681 2015 | Rockwell Diamonds Inc. | Rockwell looks to conclude its recently announced acquisition of Remhoogte/Holsloot. | Rockwell Diamonds Inc., May 27, 1p. | Africa, South Africa | News item - press release |
DC201507-1682 2015 | Rockwell Diamonds Inc. | Rockwell turns to the future after closing the Bondeo 140 CC acquisition. | Rockwell Diamonds Inc., June 25, 4p. | Africa, South Africa | News item - press release |
DC201508-1683 2015 | Rockwell Diamonds Inc. | Rockwell gets through a tough quarter with support from key shareholders and outlines future plans following recent Bondeo 140 cc acquisition. | Rockwell Diamonds Inc., July 14, 5p. | Africa, South Africa | News item - press release |
DC201510-2364 2015 | Rockwell Diamonds Inc. | Rockwell records higher grades and increased sales in Q2 off the back of the Remhoogte Holsloot Complex acquisition. | Rockwell Diamonds Inc., Sept. 21, 5p. | Africa, South Africa | News item - press release |
DC201511-2404 2015 | Rockwell Diamonds Inc. | Rockwell delivers Q2 bottom line profit. | Rockwell Diamonds Inc., Oct. 15, 6p. | Africa, South Africa | News item - press release |
DS201512-1961 2015 | Romano, M., Cifelli, TR.L. | 100 years of continental drift. | Science, Vol. 350, 6263, pp. 915-916. | Mantle | History - drift |
| Abstract: Alfred Wegener (1880-1930) was a leading explorer, geophysicist, and meteorologist from Germany, and pioneer in the exploration of Greenland (1). His seminal volume of meteorology (2) is universally considered a fundamental manual for this discipline and was long a reference text for students and specialists. Wegener's preeminent scientific legacy, however, is the continental drift hypothesis. He first presented his thesis to the scientific community on 6 January 1912 at the Geological Society of Frankfurt am Main, but his famous monograph on the subject dates to 1915 (3). |
DS201511-1871 2003 | Rombouts, L. | Assessing the diamond potential of kimberlites from discovery to bulk sampling. | Mineralium Deposita, Vol. 38, pp. 496-504. Available pdf | Global | Microdiamonds - responses |
| Abstract: The economic evaluation of diamond-bearing kimberlites is usually carried out in four stages. Expenditure tends to increase by an order of magnitude at each successive stage. At the end of each stage, the sample results should be critically appraised before deciding to proceed to the next phase. In the first stage, even before individual kimberlite bodies have been discovered, the indicator mineral geochemistry will give a first rough idea of the diamond potential. The relative abundance of harzburgitic pyropes (subcalcic chrome-rich) is often directly correlated with the diamond grade. In the next stage, when the kimberlite body has been discovered, a relatively small sample of a few hundred kilograms will be enough to recover sufficient microdiamonds to allow an extrapolation of the size distribution towards the commercial-sized diamonds and a rough estimate of their grade. If positive, the third stage should be a limited bulk sampling programme (order of 200 tonnes) to determine the commercial-sized diamond grade, expressed as carats per tonne. The aim of the final stage is to obtain a parcel of the order of 1,000 carats to estimate the average commercial value of the diamonds. The robustness and reliability of the grade and value estimates can be verified with extreme value analysis and by obtaining the confidence limits with bootstrapping. |
DS201508-0374 2015 | Rondenay, S. | The LAB in Limbo-Seismological insights into the Lithosphere-Asthenosphere system at subduction zones. | Seminar speaker July 21, U of T., 1/2p. Abstract available. | Mantle | Subduction |
DS201511-1872 2015 | Roskin, G.A. | Synthetic gem quality diamonds: the product, the perception and the retailer. | GemGuide, Vol. 34, 4, pp. 8-10. | Technology | Synthetics |
DM201501-0977 2014 | Rough-Polished | Stellar ups diamond grade, resource for Dyke 1 to 1.45 carats. | rough-polished.com, Dec. 1, 1/4p. | Africa, Sierra Leone | News item - Stellar |
DM201501-0978 2014 | Rough-Polished | Kimberley gets environmental nod as it seeks Botswana's Lerala mine. | rough-polished.com, Dec. 1, 1/4p. | Africa, Botswana | News item - Kimberley |
DM201501-0979 2014 | Rough-Polished | Alrosa to build the new "Burevesnik" innovation centre by 2017 for $ 26 million ( x ray equipment ). | rough-polished.com, Dec. 4, 1/4p. | Russia | News item - Alrosa |
DM201501-0980 2014 | Rough-Polished | We fully support Zimbabwe organizing tenders at home - AWDC boss. | rough-polished.com, Dec. 1, 1/2p. | Africa, Zimbabwe | News item - First Element |
DM201501-0981 2014 | Rough-Polished | Debswana says 2014 a good year, revenue widens. | rough-polished.com, Dec. 4, 1/4p. | Africa, Botswana | News item - Debswana |
DM201501-0982 2014 | Rough-Polished | Stellar set to generate early cash flow from surface mining at Tongo Dyke-1. | rough-polished.com, Dec. 4, 1/4p. | Africa, Ghana | News item - Stellar |
DM201501-0983 2014 | Rough-Polished | Diamcor loss narrows. | rough-polished.com, Dec. 3, 1/4p. | Africa, South Africa | News item - Diamcor |
DM201501-0984 2014 | Rough-Polished | Zimbabwe ordered ZMDC to publish financial statements. | rough-polished.com, Dec. 3, 1/4p. | Africa, Zimbabwe | News item - ZMDC |
DM201501-0985 2014 | Rough-Polished | Analysts at Barclay's Capital raised the target price for Alrosa's stock saying to buy. | rough-polished.com, Dec. 2, 1/4p. | Russia | News item - Alrosa |
DM201501-0986 2014 | Rough-Polished | Dat a exchange between Belgium and Chin a on rough diamond trade now fully automated. | rough-polished.com, Dec. 2, 1/4p. | Europe, Belgium, China | News item - legal |
DM201501-0987 2014 | Rough-Polished | Debswana recovers first stones from Jaweng tailings. | rough-polished.com, Dec. 5, 1/4p. | Africa, Botswana | News item - Debswana |
DM201501-0988 2014 | Rough-Polished | Botswana diamond manufacturers up in arms with government over levy. | rough-polished.com, Dec. 5, 1/4p. | Africa, Botswana | News item - legal |
DM201501-0989 2014 | Rough-Polished | Our goal is to create a think tank, which will come up with ideas how to reach outside our closed circuit and bring people the message about diamonds, tell them why they should buy them. | rough-polished.com, Dec. 8, 1p. | Global | News item - WDMF |
DM201501-0990 2014 | Rough-Polished | Leaders to deliberate on marketing and financing of global diamond industry. | rough-polished.com, Dec. 8, 1/4p. | Global | News item - WDMF |
DM201501-0991 2014 | Rough-Polished | Petra's BEE partners settle loans. | rough-polished.com, Dec. 8, 1/4p. | Africa, South Africa | News item - Petra |
DM201501-0992 2014 | Rough-Polished | Diamcor sells almost 3,500 carats in Q2 2015 Krone-Endora | rough-polished.com, Dec. 8, 1/4p. | Africa, South Africa | News item - Diamcor |
DM201501-0993 2014 | Rough-Polished | Alrosa held a meeting with long-term clients… market perspective. | rough-polished.com, Dec. 9, 1/4p. | Russia | News item - Alrosa |
DM201501-0994 2014 | Rough-Polished | Alrosa will take part in bidding for the right to mine diamonds at Molodo in Yakutia. Alluvials | rough-polished.com, Dec. 9, 1/4p. | Russia | News item - Alrosa |
DM201501-0995 2014 | Rough-Polished | Belgian court rules in favour of Zim, dislodges attachment of gems worth over $ 45 million by Amari ( Marange) | rough-polished.com, Dec. 9, 1/4p. | Africa, Zimbabwe | News item - Amari |
DM201501-0996 2014 | Rough-Polished | Alrosa sold a diamond for $ 1.8 million at Sotheby's 47.48 carats. | rough-polished.com, Dec. 11, 1/4p. | Russia | News item - Alrosa |
DM201501-0997 2014 | Rough-Polished | Indian government confirms proposal for SNZ for rough diamonds. ( Special Notified Zone) | rough-polished.com, Dec. 11, 1/4p. | India | News item - SNZ |
DM201501-0998 2014 | Rough-Polished | De Beers to produce up to 34 mln carats next year. | rough-polished.com, Dec. 11, 1/4p. | Global | News item - De Beers |
DM201501-0999 2014 | Rough-Polished | Stellar acquires a $ 2mln bridging loan. | rough-polished.com, Dec. 11, 1/4p. | Africa, Guinea | News item - Stellar |
DM201501-1000 2014 | Rough-Polished | NDTC pays $ 62 million in annual royalties to Namibia. | rough-polished.com, Dec. 11, 1/4p. | Africa, Namibia | News item - NDTC |
DM201501-1001 2014 | Rough-Polished | Lucara says Karowe to produce 400 k carats next year. | rough-polished.com, Dec. 10, 1/4p. | Africa, Botswana | News item - Lucara |
DM201501-1002 2014 | Rough-Polished | Amari not giving up on Zim diamonds, appeals latest ruling. | rough-polished.com, Dec. 10, 1/4p. | Africa, Zimbabwe | News item - Amari |
DM201501-1003 2014 | Rough-Polished | Alrosa supervisory board approves 2015 budget. | rough-polished.com, Dec. 12, 1/4p. | Russia | News item - Alrosa |
DM201501-1004 2014 | Rough-Polished | Alrosa inks agreement with 12 Indian companies for direct rough supply. | rough-polished.com, Dec. 12, 1/4p. | Russia, India | News item - Alrosa |
DM201501-1005 2014 | Rough-Polished | Zim diamond miners accused of tax evasion. Marange | rough-polished.com, Dec. 12, 1/4p. | Africa, Zimbabwe | News item - legal |
DM201501-1006 2014 | Rough-Polished | Lucapa records more exceptional diamond grades at Lulo. | rough-polished.com, Dec. 12, 1/4p. | Africa, Angola | News item - Lucapa |
DM201501-1007 2014 | Rough-Polished | Kiran Gems signs long term supply contract with Alrosa at WDC. | rough-polished.com, Dec. 16, 1/4p. | Russia | News item - Alrosa |
DM201501-1008 2014 | Rough-Polished | Historic world diamond conference exceeds expectations. | rough-polished.com, Dec. 16, 1/4p. | India | News item - WDC |
DM201501-1009 2014 | Rough-Polished | Angola earns $ 6.5 billion in 9 months from diamond revenue. | rough-polished.com, Dec. 16, 1/4p. | Africa, Angola | News item - economics |
DM201501-1010 2014 | Rough-Polished | Rockwell production, revenue continues to go up. | rough-polished.com, Dec. 16, 1/4p. | Africa, South Africa | News item - Rockwell |
DM201501-1011 2014 | Rough-Polished | Alrosa announced liquidity improvement measures. | rough-polished.com, Dec. 15, 1/4p. | Russia | News item - Alrosa |
DM201501-1012 2014 | Rough-Polished | Demand for diamonds in the world is very high - AWDC. ( Antwerp) | rough-polished.com, Dec. 15, 1p. | Global | News item - economics |
DM201501-1013 2014 | Rough-Polished | Diamond industry organizations to struggle against conflict diamonds. | rough-polished.com, Dec. 15, 1/4p. | Global | News item - KP |
DM201501-1014 2014 | Rough-Polished | Dominion Diamond revenue soared 50% in Q3 2015 financial year. | rough-polished.com, Dec. 15, 1/4p. | Canada, Northwest Territories | News item - Dominion |
DM201501-1015 2014 | Rough-Polished | Kristall will buy 11,500 carats of rough diamonds in the course of one month. | rough-polished.com, Dec. 17, 1/4p. | Russia | News item - Kristall |
DM201501-1016 2014 | Rough-Polished | Alrosa expects profits to decline 2.6 times in 2014 due to weakened ruble. | rough-polished.com, Dec. 19, 1/4p. | Russia | News item - Alrosa |
DM201501-1017 2014 | Rough-Polished | Kristall production corporation OAO makes an exclusive offer at its online marketplace. | rough-polished.com, Dec. 19, 1/4p. | Russia | News item - Kristall |
DM201501-1018 2014 | Rough-Polished | Rising diamond revenues helping Angola offset dropping oil income. | rough-polished.com, Dec. 19, 1/4p. | Africa, Angola | News item - Endiama |
DM201501-1019 2014 | Rough-Polished | Diamond output of Severalmaz will exceed 1.6 million carats by the end of the year. | rough-polished.com, Dec. 18, 1/4p. | Russia | News item - Severalmaz |
DM201502-1020 2014 | Rough-Polished | The Diamond Valley project in Yakutsk will not be implemented. | rough-polished.com, Dec. 24, 1/4p. | Russia | News item - Diamond Valley |
DM201502-1021 2014 | Rough-Polished | Lucara to offload Lesotho's Mothae asset. | rough-polished.com, Dec. 24, 1/4p. | Africa, Lesotho | News item - Lucara |
DM201502-1022 2014 | Rough-Polished | Scio Diamond Technology gets $ 2.5 million growth funding. | rough-polished.com, Dec. 24, 1/4p. | Technology | News item - Scio |
DM201502-1023 2014 | Rough-Polished | Weak ruble may diminish diamond prices by 2-5 percent. | rough-polished.com, Dec. 23, 1/4p. | Russia | News item - economics |
DM201502-1024 2014 | Rough-Polished | Namibia's Q3 diamond output slides. Fell by 12.3 % to 446,637 carats | rough-polished.com, Dec. 22, 1/4p. | Africa, Namibia | News item - Namdeb |
DM201502-1025 2014 | Rough-Polished | Lucapa to start mining alluvial diamonds at Angola's Lulo next month. | rough-polished.com, Dec. 22, 1/4p. | Africa, Angola | News item - Lucapa |
DM201502-1026 2014 | Rough-Polished | By next March, Alrosa plans to bring its foreign currency assets to the level of October 2014. | rough-polished.com, Dec. 29, 1/4p. | Russia | News item - Alrosa |
DM201502-1027 2014 | Rough-Polished | GSI opens new lab in Botswana. | rough-polished.com, Dec. 29, 1/4p. | Africa, Botswana | News item - GSI |
DM201502-1028 2014 | Rough-Polished | Another kimberlite pipe found in Anantapur district in India. KL-7 | rough-polished.com, Dec. 29, 1/4p. | India, Andhra Pradesh | News item - Kalyandurg |
DM201502-1029 2014 | Rough-Polished | Surat may have a new diamond bourse in 4 years. | rough-polished.com, Dec. 29, 1/4p. | India | News item - Surat |
DM201502-1030 2014 | Rough-Polished | Alrosa wins auction for Molodo diamond placer. | rough-polished.com, Dec. 26, 1/4p. | Russia | News item - Alrosa |
DM201502-1031 2014 | Rough-Polished | Kennady Diamonds bulk sample indicates grade of 2.59 carats per tonne. | rough-polished.com, Dec. 26, 1/4p. | Canada, Northwest Territories | News item - Kennady |
DM201502-1032 2014 | Rough-Polished | Diamcor Mining to raise $ 3 million in private stock placement. | rough-polished.com, Dec. 26, 1/4p. | Africa, South Africa | News item - Diamcor |
DM201502-1033 2014 | Rough-Polished | We are highly optimistic about increased demand in 2015 - Vipul Shah | rough-polished.com, Dec. 26, 1/4p. | Global | News item - GJEPC |
DM201502-1034 2014 | Rough-Polished | U.S. online Christmas ecommerce spending + 15% to $ 48 billion. | rough-polished.com, Dec. 25, 1/4p. | Global, United States | News item - economics |
DM201502-1035 2014 | Rough-Polished | EPL Diamond will continue to buy rough from Alrosa. | rough-polished.com, Dec. 31, 1/4p. | Russia | News item - Alrosa |
DM201502-1036 2014 | Rough-Polished | Lukoil plans to produce 2 million carats of rough in 2015. | rough-polished.com, Dec. 31, 1/4p. | Russia | News item - Lukoil |
DM201502-1037 2015 | Rough-Polished | Diamonds lend class, grandeur and style to any outfit and occasion. | rough-polished.com, Jan. 5, 1p. | India | News item - diamond |
DM201502-1038 2015 | Rough-Polished | Angola's Catoca says 2014 was a difficult year, outlines priorities for 2015. | rough-polished.com, Jan. 12, 1/4p. | Africa, Angola | News item - Catoca |
DM201502-1039 2015 | Rough-Polished | Stellar recovers diamond ore grade of 15 cpht from Baoule trial mining. | rough-polished.com, Jan. 12, 1/4p. | Africa, Guinea | News item - Stellar |
DM201502-1040 2015 | Rough-Polished | Russia will develop the Sestroretsk diamond pipe. Discussion is about INREAL and synthetics. | rough-polished.com, Jan. 12, 1p. | Russia | News item - Inreal |
DM201502-1041 2015 | Rough-Polished | The Ghaghoo narrative. | rough-polished.com, Jan. 15, 1p. | Africa, Botswana | News item - Gem Diamonds |
DM201502-1042 2015 | Rough-Polished | A happier year ahead? | rough-polished.com, Jan. 14, 1/4p. | Global | News item - prices and liquidity |
DM201502-1043 2015 | Rough-Polished | Diamond producers fear competition as consumers find new best friends. | rough-polished.com, Jan. 13, 1/4p. | Global | News item - markets |
DM201502-1044 2015 | Rough-Polished | Diamond beneficiation seen as potential answer to Zim's economic malaise. | rough-polished.com, Jan. 15, 1/4p. | Africa, Zimbabwe | News item - polishing |
DM201502-1045 2015 | Rough-Polished | Credit Suisse evaluates Alrosa market perspective high. | rough-polished.com, Jan. 14, 1/4p. | Russia | News item - Alrosa |
DM201502-1046 2015 | Rough-Polished | Analytics: Synthetic diamonds: response adequate to challenge. | rough-polished.com, Jan. 14, 1p. | Technology | News item - synthetics |
DM201502-1047 2015 | Rough-Polished | Barclays Capital analytics raised the traget price of Alrosa securities. | rough-polished.com, Jan. 16, 1/4p. | Russia | News item - Alrosa |
DM201502-1048 2015 | Rough-Polished | Tax returns on diamond mining in Arkhangelsk region soared six fold in 2014. | rough-polished.com, Jan. 16, 1/4p. | Russia, Archangel, Kola Peninsula | News item - economics |
DM201502-1049 2015 | Rough-Polished | Rio Tinto's Chief Executive presses Indian PM for Bunder project approval. | rough-polished.com, Jan. 16, 1/4p. | India | News item - Rio Tinto |
DM201502-1050 2015 | Rough-Polished | First Ghaghoo tender by Gem Diamonds in Antwerp. | rough-polished.com, Jan. 19, 1/4p. | Africa, Botswana | News item - Gem Diamonds |
DM201502-1051 2015 | Rough-Polished | World diamond market is driven by globalization. Marcel Zalc. | rough-polished.com, Jan. 19, 1p. | Global | News item - markets |
DM201502-1052 2015 | Rough-Polished | Rough diamond demand by Zim cutters remain 'very low'. | rough-polished.com, Jan. 20, 1/4p. | Africa, Zimbabwe | News item - cutting |
DM201502-1053 2015 | Rough-Polished | Angola to re-open diamond cutting factory next month. | rough-polished.com, Jan. 21, 1/4p. | Africa, Angola | News item - Sodiam |
DM201502-1054 2015 | Rough-Polished | Rio Tinto's Zim diamond mine Q4' 2014 output drops. Murowa | rough-polished.com, Jan. 21, 1/4p. | Africa, Zimbabwe | News item - Rio Tinto |
DM201502-1055 2015 | Rough-Polished | Polished diamond demand in Russia grew 62% in December. | rough-polished.com, Jan. 21, 1/4p. | Russia | News item - Kristall |
DM201502-1056 2015 | Rough-Polished | Angola's Endiama expects new 'large' diamond deposit recovery in Angola. | rough-polished.com, Jan. 23, 1/4p. | Africa, Angola | News item - Endiama |
DM201502-1057 2015 | Rough-Polished | India to develop contacts with Russian diamond companies. | rough-polished.com, Jan. 26, 1/4p. | India, Russia | News item - markets |
DM201502-1058 2015 | Rough-Polished | Sunergy prepares for second diamond parcel sale, Sierra Leonean operation expansion. | rough-polished.com, Jan. 26, 1/4p. | Africa, Sierra Leone | News item - Sunergy |
DM201503-1059 2015 | Rough-Polished | Alrosa conveys condolences on the passing of Fyodor Andreev. | rough-polished.com, Jan. 30, 1/4p. | Russia | News item - Alrosa |
DM201503-1060 2015 | Rough-Polished | Paragon signs a $ 12 m equity, debt finance package for Lemphane. | rough-polished.com, Jan. 30, 1/4p. | Africa, Lesotho | News item - Paragon |
DM201503-1061 2015 | Rough-Polished | Alrosa Group performance in 2014: output reached 36.21 million carats, sales $ 5.05 billion. | rough-polished.com, Jan. 29, 1/4p. | Russia | News item - Alrosa |
DM201503-1062 2015 | Rough-Polished | Lucapa commences alluvial diamond mining at Lulo concession. | rough-polished.com, Jan. 29, 1/4p. | Africa, Angola | News item - Lucapa |
DM201503-1063 2015 | Rough-Polished | Jay kimberlite deposit to extend Ekati life cycle. | rough-polished.com, Jan. 29, 1/4p. | Canada, Northwest Territories | News item - Dominion |
DM201503-1064 2015 | Rough-Polished | Israeli diamond bourse leaders meet with De beers delegation. | rough-polished.com, Jan. 29, 1/4p. | Europe, Israel | News item - De Beers |
DM201503-1065 2015 | Rough-Polished | A new platform for diamond e-commerce. Www.asapodiamonds.com | rough-polished.com, Jan. 29, 1/4p. | Global | News item - asapodiamnds |
DM201503-1066 2015 | Rough-Polished | Zim's plans to merge Marange diamond firms facing resistence. | rough-polished.com, Jan. 28, 1/4p. | Africa, Zimbabwe | News item - Marange |
DM201503-1067 2015 | Rough-Polished | Sarine and HRD Antwerp to offer interoperability of computerized systems. | rough-polished.com, Jan. 28, 1/4p. | Technology | News item - Sarine |
DM201503-1068 2015 | Rough-Polished | Alrosa on the top of Corporate Social Responsibility list of Russian companies in January. | rough-polished.com, Jan. 27, 1/4p. | Russia | News item - Alrosa |
DM201503-1069 2015 | Rough-Polished | LUKOIL diamond project to pay off in 5-6 years. Grib | rough-polished.com, Feb. 3, 1/4p. | Russia, Kola Peninsula, Archangel | News item - LuKOIL |
DM201503-1070 2015 | Rough-Polished | Marange diamond miners rapped for failure to develop local communities. | rough-polished.com, Feb. 3, 1/4p. | Africa, Zimbabwe | News item - Marange |
DM201503-1071 2015 | Rough-Polished | Diamonds to fund a third of Botswana's state budget. | rough-polished.com, Feb. 4, 1/4p. | Africa, Botswana | News item - economics |
DM201503-1072 2015 | Rough-Polished | Angola, U.S. pledge to enforce KP core principles. | rough-polished.com, Feb. 4, 1/4p. | Africa, Angola, United States | News item - KP |
DM201503-1073 2015 | Rough-Polished | The biggest polished synthetic diamond was created in Russia 10.31 IIa type. | rough-polished.com, Feb 2, 1/4p. | Technology | News item - synthetics |
DM201503-1074 2015 | Rough-Polished | Alrosa to cut on diamond stockpile, reduce credit burden in 2015. | rough-polished.com, Feb. 5, 1/4p. | Russia | News item - Alrosa |
DM201503-1075 2015 | Rough-Polished | Angola re-opens diamond cutting, polishing factory. Sodiam | rough-polished.com, Feb. 5, 1/4p. | Africa, Angola | News item - Sodiam |
DM201503-1076 2015 | Rough-Polished | Rio's Murowa mine to close weighed down by new tax regime. | rough-polished.com, Feb. 5, 1/4p. | Africa, Zimbabwe | News item - Rio Tinto |
DM201503-1077 2015 | Rough-Polished | Botswana diamond cutter, Teemane Manufacturing is set to shut down its 20 year operations due to low prices. | rough-polished.com, Feb. 5, 1/4p. | Africa, Botswana | News item - Teemane |
DM201503-1078 2015 | Rough-Polished | Diamond polishers await outcome of Namibia-De Beers talks. | rough-polished.com, Feb. 9, 1/4p. | Africa, Namibia | News item - Debswana |
DM201503-1079 2015 | Rough-Polished | Grizzly discoveries updates on resource properties. Buffalo Head Hills. | rough-polished.com, Feb. 9, 1/4p. | Canada, Alberta | News item - Grizzly |
DM201503-1080 2015 | Rough-Polished | Kennedy Diamonds announces $ 16 million share placement. ( Can $20m) | rough-polished.com, Feb. 12, 1/4p. | Canada, Northwest Territories | News item - press release |
DM201503-1081 2015 | Rough-Polished | South Africa to provide mining regulatory certainty. | rough-polished.com, Feb. 12, 1/4p. | Africa, South Africa | News item - legal |
DM201503-1082 2015 | Rough-Polished | Angola's Endiama courts investors. | rough-polished.com, Feb. 11, 1/4p. | Africa, Angola | News item - Endiama |
DM201503-1083 2015 | Rough-Polished | Lomonosov diamond deposit in the Arkangelsk region produced 6 million carats of diamonds since 2005. | rough-polished.com, Feb. 10, 1/4p. | Russia | News item - Lomonosov |
DM201503-1084 2015 | Rough-Polished | De Beers says AMS has never mistaken natural diamonds for synthetic. | rough-polished.com, Feb. 12, 1/4p. | Technology | News item - De Beers |
DM201503-1085 2015 | Rough-Polished | SA State diamond trader buys less rough. | rough-polished.com, Feb. 12, 1/4p. | Africa, South Africa | News item - Diamond Trader |
DM201503-1086 2015 | Rough-Polished | Diamond mining in India: projects developed by Vajra diamond mining. Charles Devenish | rough-polished.com, Feb. 11, 3p. | India | News item - Vajra |
DM201503-1087 2015 | Rough-Polished | Angola says artisanal diamond miners produced 935,000 carats in 2014. | rough-polished.com, Feb. 13, 1/4p. | Africa, Angola | News item - artisans |
DM201503-1088 2015 | Rough-Polished | Rio Tinto registers 6 % in diamond revenues. | rough-polished.com, Feb. 13, 1/4p. | Global | News item - Rio Tinto |
DM201503-1089 2015 | Rough-Polished | DRC denies suspending mining code talks. | rough-polished.com, Feb. 13, 1/4p. | Africa, Democratic Republic of Congo | News item - legal |
DM201503-1090 2015 | Rough-Polished | De Beers 2014 sales, production up. | rough-polished.com, Feb. 16, 1/4p. | Global | News item - De Beers |
DM201503-1091 2015 | Rough-Polished | Rosgeologiya estimates inferred diamond resources in the Tarydakskaya area. | rough-polished.com, Feb. 16, 1/4p. | Russia | News item - Rosgeologiya |
DM201503-1092 2015 | Rough-Polished | Angola's diamond reserves seen at 300 million carats. | rough-polished.com, Feb. 16, 1/4p. | Africa, Angola | News item - Endiama |
DM201503-1093 2015 | Rough-Polished | No correlation between Namibia-De Beers talks and sightholders contracts - Katali | rough-polished.com, Feb. 16, 1/4p. | Africa, Namibia | News item - De Beers |
DM201503-1094 2015 | Rough-Polished | Zambia digs in on mining royalties. | rough-polished.com, Feb. 16, 1/4p. | Africa, Zambia | News item - legal |
DM201503-1095 2015 | Rough-Polished | Botswana minister against rescue package for diamond manufacturer. Teemane | rough-polished.com, Feb. 18, 1/4p. | Africa, Botswana | News item - Teemane |
DM201503-1096 2015 | Rough-Polished | De Beers says diamond prices to recover in Q2. | rough-polished.com, Feb. 17, 1/4p. | Global | News item - De Beers |
DM201503-1097 2015 | Rough-Polished | India interested in small Angolan diamonds. | rough-polished.com, Feb. 17, 1/4p. | India | News item - Endiama |
DM201503-1098 2015 | Rough-Polished | Namdeb's contractor's workers strike over wages. | rough-polished.com, Feb. 19, 1/4p. | Africa, Namibia | News item - Namdeb |
DM201503-1099 2015 | Rough-Polished | De Beers to spend 3 Billion on diamond mining operations. | rough-polished.com, Feb. 19, 1/4p. | Global | News item - De Beers |
DM201503-1100 2015 | Rough-Polished | Stellar ready for first Baoule diamond sale. | rough-polished.com, Feb. 20, 1/4p. | Africa, Guinea | News item - Stellar |
DM201503-1101 2015 | Rough-Polished | Petra boosts H1 revenue despite drop in output. | rough-polished.com, Feb. 20, 1/4p. | Africa, South Africa | News item - Petra |
DM201503-1102 2015 | Rough-Polished | Fancy coloured diamond index reflects stable prices in Q4 2014. | rough-polished.com, Feb. 19, 1/4p. | Global | News item - colored diamonds |
DM201504-1103 2015 | Rough-Polished | Dominion's Q4 sales reached $ 240 million. | rough-polished.com, Feb. 24, 1/4p. | Canada, Northwest Territories | News item - Dominion |
DM201504-1104 2015 | Rough-Polished | Sarine Technologies reports a 15% revenue growth in 2014. | rough-polished.com, Feb. 24, 1/4p. | Technology | News item - Sarine |
DM201504-1105 2015 | Rough-Polished | Lucara boosts full year revenues to $ 266 million. Karowe | rough-polished.com, Feb. 24, 1/4p. | Africa, Botswana | News item - Lucara |
DM201504-1106 2015 | Rough-Polished | Alrosa is one of the Russian companies most frequently mention in international media. | rough-polished.com, Feb. 26, 1/4p. | Russia | News tem - Alrosa |
DM201504-1107 2015 | Rough-Polished | Alrosa plans to repay more than $ 1 billion in loans by end of 2015. | rough-polished.com, Feb. 25, 1/4p. | Russia | News item - Alrosa |
DM201504-1108 2015 | Rough-Polished | Zim minister says Marange diamonds have dramatically shrunk. | rough-polished.com, Feb. 25, 1/4p. | Africa, Zimbabwe | News item - Marange |
DM201504-1109 2015 | Rough-Polished | Namibia De Beers talks scheduled to end in June. | rough-polished.com, Feb. 24, 1p. | Africa, Namibia | News item - De Beers |
DM201504-1110 2015 | Rough-Polished | Botswana Diamonds, Alrosa focus exploration work on 3 Orapa licence areas. | rough-polished.com, Feb. 27, 1/4p. | Africa, Botswana | News item - Botswana Diamonds |
DM201504-1111 2015 | Rough-Polished | Peregrine confirms a 8.57 million carat inferred resource at CH-6 kimberlite. | rough-polished.com, Feb. 17, 1/4p. | Canada, Nunavut, Baffin Island | News item - Peregrine |
DM201504-1112 2015 | Rough-Polished | Lucapa suspends trading ahead of announcement on funding. Lulo | rough-polished.com, Feb. 27, 1/4p. | Africa, Angola | News item - Lucapa |
DM201504-1113 2015 | Rough-Polished | Sberbank CIB said Alrosa securities undervalued. | rough-polished.com, Mar. 4, 1/4p. | Russia | News item - Alrosa |
DM201504-1114 2015 | Rough-Polished | Clever people stole info on Zim diamonds hidden by De Beers - Mugabe. | rough-polished.com, Mar. 4, 1/4p. | Africa, Zimbabwe | News item - De Beers |
DM201504-1115 2015 | Rough-Polished | Stellar starts Antwerp rough tender. | rough-polished.com, Mar. 4, 1/4p. | Africa, Guinea | News item - Stellar |
DM201504-1116 2015 | Rough-Polished | Russian rough exports up 7.7% Ministry of Finance. | rough-polished.com, Mar. 4, 1/4p. | Russia | News item - production |
DM201504-1117 2015 | Rough-Polished | Rio Tinto streamlines organizational structure to drive greater value. | rough-polished.com, Mar. 3, 1/4p. | Global | News item - Rio Tinto |
DM201504-1118 2015 | Rough-Polished | North Arrow reports an update on Qilalugaq bulk sampling processing. | rough-polished.com, Mar. 2, 1/4p. | Canada, Nunavut | News item - North Arrow |
DM201504-1119 2015 | Rough-Polished | Liquidity challenged Botswana diamond cutters to emerge stronger - official. | rough-polished.com, Mar. 2, 1/4p. | Africa, Botswana | News item - cutting |
DM201504-1120 2015 | Rough-Polished | Diamonds from Trans Hex's Angola, SA mines fetch weak average prices. | rough-polished.com, Mar. 6, 1/4p. | Africa, Angola, South Africa | News item - Trans Hex |
DM201504-1121 2015 | Rough-Polished | Lucapa inks $ 15 million bridge finance facility, raises $ 4.8 m. Lulo | rough-polished.com, Mar. 6, 1/4p. | Africa, Angola | News item - Lucapa |
DM201504-1122 2015 | Rough-Polished | Ex-Mbada workers demand terminal benefits, beseige company offices. | rough-polished.com, Mar. 6, 1/4p. | Africa, Zimbabwe | News item - Mbada |
DM201504-1123 2015 | Rough-Polished | Pangolin recovers more diamonds from Botswana's Malatswae project. | rough-polished.com, Mar. 6, 1/4p. | Africa, Botswana | News item - Pangolin |
DM201504-1124 2015 | Rough-Polished | Rio Tinto launches world first analytics excellence centre in India. | rough-polished.com, Mar. 6, 1/4p. | India | News item - Rio Tinto |
DM201504-1125 2015 | Rough-Polished | Zim gets back majority of diamonds previously withheld in Belgium. | rough-polished.com, Mar. 6, 1/4p. | Africa, Zimbabwe | News item - legal |
DM201504-1126 2015 | Rough-Polished | Morgan Stanley doubled its estimate of Alrosa shares, confirming the 'buy' rating. | rough-polished.com, Mar. 11, 1/4p. | Russia | News item - Alrosa |
DM201504-1127 2015 | Rough-Polished | WDMF lauds diamond mining industry promotion efforts. | rough-polished.com, Mar. 11, 1/4p. | Global | News item - WDMF |
DM201504-1128 2015 | Rough-Polished | Alrosa launches mining at Botuobinskaya kimberlte pipe. | rough-polished.com, Mar. 10, 1/4p. | Russia | News item - Alrosa |
DM201504-1129 2015 | Rough-Polished | Alrosa, Botswana Diamonds restart exploration in Orapa. | rough-polished.com, Mar. 10, 1/4p. | Africa, Botswana | News item - Alrosa, Botswana Diamonds |
DM201504-1130 2015 | Rough-Polished | Namibian GVt gets draft agreement on new sales deal with De Beers. Debswana | rough-polished.com, Mar. 10, 1/4p. | Africa, Namibia | News item - Debswana |
DM201504-1131 2015 | Rough-Polished | Angola approves new artisanal diamond mining licences. | rough-polished.com, Mar. 13, 1/4p. | Africa, Angola | News item - legal |
DM201504-1132 2015 | Rough-Polished | Firestone Diamonds loss narrows. | rough-polished.com, Mar. 13, 1/4p. | Africa, Lesotho, Botswana | News item - Firestone |
DM201504-1133 2015 | Rough-Polished | Alrosa is major budget contributing company for Yakutia. | rough-polished.com, Mar. 12, 1/4p. | Russia, Yakutia | News item - Alrosa |
DM201504-1134 2015 | Rough-Polished | Alrosa may revise its low margin projects if diamond prices decline. | rough-polished.com, Mar. 12, 1/4p. | Russia | News item - Alrosa |
DM201504-1135 2015 | Rough-Polished | Smolensk Kristall will sell diamonds worth RUB 3 billion to Gokran. | rough-polished.com, Mar. 12, 1/4p. | Russia | News item - Kristall |
DM201504-1136 2015 | Rough-Polished | Rockwell says Remhoogte to add 63,500 ct to its diamond inventory. | rough-polished.com, Mar. 12, 1/4p. | Africa, South Africa | News item - Rockwell |
DM201504-1137 2015 | Rough-Polished | NMDC to SC for extension of Panna mining period. | rough-polished.com, Mar. 12, 1/4p. | India | News item - NMDC |
DM201504-1138 2015 | Rough-Polished | Alrosa shares included in market vector Russia index. | rough-polished.com, Mar. 17, 1/4p. | Russia | News item - Alrosa |
DM201504-1139 2015 | Rough-Polished | World's biggest diamond producers to converge at 2nd DDC. | rough-polished.com, Mar. 17, 1/4p. | Global | News item - Dubai Diamond Conference |
DM201504-1140 2015 | Rough-Polished | Anglo says De Beers exploration expenditure topped $ 37 million in 2014. | rough-polished.com, Mar. 17, 1/4p. | Global | News item - Anglo |
DM201504-1141 2015 | Rough-Polished | Paragon seeks to acquire new mine ahead of stage 1 diamond production at Lemphane. | rough-polished.com, Mar. 17, 1/4p. | Africa, Lesotho | News item - Paragon |
DM201504-1142 2015 | Rough-Polished | GIA verifies Sarine's software products. | rough-polished.com, Mar. 17, 1/4p. | Technology | News item - Sarine |
DM201504-1143 2015 | Rough-Polished | There are immense potentialities in India for diamond mining T. M. Babu | rough-polished.com, Mar. 17, 1/4p. | India | News item - mining |
DM201504-1144 2015 | Rough-Polished | Zim diamond firms "agree" to merger. | rough-polished.com, Mar. 19, 1/4p. | Africa, Zimbabwe | News item - legal |
DM201504-1145 2015 | Rough-Polished | Diamond Corp SA subsidiary inks $ 7 m royalty deal ( Lace with Acrux esources 3% net revenue royalty) on the first 12 m carats. | rough-polished.com, Mar. 19, 1/4p. | Africa, South Africa | News item - DiamondCorp |
DM201504-1146 2015 | Rough-Polished | Gem Diamonds revenue up 27% to $ 271 ,m | rough-polished.com, Mar. 18, 1/4p. | Africa, Lesotho | News item - Gem Diamonds |
DM201504-1147 2015 | Rough-Polished | Sarine launches Sarine Profile system for diamond trade. | rough-polished.com, Mar. 18, 1/4p. | Technology | News item - Sarine |
DM201504-1148 2015 | Rough-Polished | Rio Tinto pays Zimbabwe $ 14 mln in taxes. | rough-polished.com, Mar. 20, 1/4p. | Africa, Zimbabwe | News item - Rio Tinto |
DM201504-1149 2015 | Rough-Polished | De Beers to upgrade DiamondView. | rough-polished.com, Mar. 20, 1/4p. | Technology | News item - De Beers |
DM201504-1150 2015 | Rough-Polished | Alrosa increased EBITA by 36% brining it to RUB 93.9 billion in 2014 | rough-polished.com, Mar. 23, 1/4p. | Russia | News item - Alrosa |
DM201504-1151 2015 | Rough-Polished | Alfa Bank experts start to analyze Alrosa. | rough-polished.com, Mar. 23, 1/4p. | Russia | News item - Alrosa |
DM201504-1152 2015 | Rough-Polished | CIBJO diamond commission considers threat of questionable grading reports. | rough-polished.com, Mar. 23, 1/4p. | Global | News item - CIBJO |
DM201504-1153 2015 | Rough-Polished | Iia Technologies opens diamond green house in Singapore. | rough-polished.com, Mar. 23, 1/4p. | Singapore | News item - synthetics |
DM201504-1154 2015 | Rough-Polished | Alrosa plans to pay off $ 1 billion of debt this year. | rough-polished.com, Mar. 24, 1/4p. | Russia | News item - Alrosa |
DM201504-1155 2015 | Rough-Polished | Lucapa to implement two stage kimberlite exploration program at Lulo. | rough-polished.com, Mar. 24, 1/4p. | Africa, Angola | News item - Lucapa |
DM201504-1156 2015 | Rough-Polished | Antwerp Police Commissioner and diamond squad head arrested on money laundering suspicion. | rough-polished.com, Mar. 25, 1/4p. | Europe, Belgium | News item - legal |
DM201505-0937 2015 | Rough-Polished | De Beers expects exponential sales growth in Chin a for diamond industry. | rough-polished.com, Mar. 27, 1/4p. | China | News item - De Beers |
DM201505-0938 2015 | Rough-Polished | Zimbabwe diamond exports continue to decline. | rough-polished.com, Mar. 27, 1/4p. | Africa, Zimbabwe | News item - MMCZ |
DM201505-0939 2015 | Rough-Polished | Illegal diamond trade continues to flourish in CAR despite KP ban. | rough-polished.com, Mar. 27, 1/4p. | Africa, Central African Republic | News item - legal |
DM201505-0940 2015 | Rough-Polished | Alrosa executive committee discussed Udachny MPD development… Verkhne Munskoye and Zarnitsa | rough-polished.com, Mar. 26, 1/4p. | Russia | News item - Alrosa |
DM201505-0941 2015 | Rough-Polished | Zim diamond miners 'afraid to say no' to proposed merger. | rough-polished.com, Mar. 26, 1/4p. | Africa, Zimbabwe | News item - legal |
DM201505-0942 2015 | Rough-Polished | Stellar Diamonds advances key projects toward production. | rough-polished.com, Mar. 31, 1/4p. | Africa, Guinea, Sierra Leone | News item - Stellar |
DM201505-0943 2015 | Rough-Polished | Alrosa, Kristall Production Corporation sign new long term contract. | rough-polished.com, Mar. 31, 1/4p. | Russia | News item - Alrosa |
DM201505-0944 2015 | Rough-Polished | White Rivers Exploration seeks JV partner to develop SA alluvial asset. | rough-polished.com, Mar. 31, 1p. | Africa, South Africa | News item - White Rivers |
DM201505-0945 2015 | Rough-Polished | Alrosa increased its diamond reserves by 25.6 million carats in 2014, driving its output to 32.2 million carats. | rough-polished.com, Apr. 3, 1/4p. | Russia | News item - Alrosa |
DM201505-0946 2015 | Rough-Polished | Modern Russian designers to showcase jewellery at Moscow Estet fashion week. | rough-polished.com, Apr. 3, 1/4p. | Russia | News item - jewellery |
DM201505-0947 2015 | Rough-Polished | Medvedev signed government directive recommending Andrei Zharkov as candidate for Alrosa presidency. | rough-polished.com, Apr. 6, 1/4p. | Russia | News item - Alrosa |
DM201505-0948 2015 | Rough-Polished | Russian government approved of Alrosa winning alluvial deposit auction. Molodo river area | rough-polished.com, Apr. 6, 1/4p. | Russia, Yakutia | News item - Alrosa |
DM201505-0949 2015 | Rough-Polished | De Beers Group turning more sophistocated technology to identify synthetics. | rough-polished.com, Apr. 6, 1/2p. | Technology | News item - IIDGR |
DM201505-0950 2015 | Rough-Polished | AWDC renews support of DDI to sustain innovation and core functions. | rough-polished.com, Apr. 6, 1/4p. | Global | News item - DDI |
DM201505-0951 2015 | Rough-Polished | Mwana Africa $ 100 mln needed to boost diamond output at DRC mine. Miba JV | rough-polished.com, Apr. 14, 1/4p. | Africa, Democratic Republic of Congo | News item - Mwana |
DM201505-0952 2015 | Rough-Polished | Tsodilo acquires mobile DMS treatment plant for use at BK16 kimberlite project. | rough-polished.com, Apr. 14, 1/4p. | Africa, Botswana | News item - Tsodilo |
DM201505-0953 2015 | Rough-Polished | India's outlook raised by Moody's: Fitch sees faster growth. | rough-polished.com, Apr. 14, 1/4p. | India | News item - economics |
DM201505-0954 2015 | Rough-Polished | Botswana Diamonds issues shares in lieu of fees to John Teeling, others. | rough-polished.com, Apr. 14, 1/4p. | Africa, Botswana | News item - Botswana Diamonds |
DM201505-0955 2015 | Rough-Polished | Sarine announces FY2014 group performance. | rough-polished.com, Apr. 13, 1/4p. | Technology | News item - Sarine |
DM201505-0956 2015 | Rough-Polished | Dominion Diamond sales up 22%. | rough-polished.com, Apr. 10, 1/4p. | Canada, Northwest Territories | News item - Dominion |
DM201505-0957 2015 | Rough-Polished | Lucapa says Lulo alluvial mining on track to becoming cash flow positive. | rough-polished.com, Apr. 10, 1/4p. | Africa, Angola | News item - Lucapa |
DM201505-0958 2015 | Rough-Polished | Fusion alternatives and Tzoffey's to hold special tenders during international rough diamond week. | rough-polished.com, Apr. 10, 1/4p. | Global | News item - Fusion |
DM201505-0959 2015 | Rough-Polished | Alrosa will not change the dividend policy - Ryaschin. | rough-polished.com, Apr. 9, 1/4p. | Russia | News item - Alrosa |
DM201505-0960 2015 | Rough-Polished | Karelian Diamonds abandoning exploration in northern Finland. Kuhmo ( anti mining) | rough-polished.com, Apr. 9, 1/4p. | Europe, Finland | News item - Karelian Diamonds |
DM201505-0961 2015 | Rough-Polished | Igor Kevchenkov: money invested in polished diamonds and gold are the most reliable investments. | rough-polished.com, Apr. 13, 1p. | Russia | News item - economics |
DM201505-0962 2015 | Rough-Polished | Zim set to commence diamond beneficiation. ZDTC | rough-polished.com, Apr. 8, 1/4p. | Africa, Zimbabwe | News item - ZDTC |
DM201505-0963 2015 | Rough-Polished | Rosatom invented world's best diamond seeking system. Ore processing machine for diamond detection. | rough-polished.com, Apr. 15, 1/4p. | Technology | News item - Ria.ru |
DM201505-0964 2015 | Rough-Polished | Botswana diamond polishers grapple with high operational costs. | rough-polished.com, Apr. 15, 1/4p. | Africa, Botswana | News item - polishers |
DM201505-0965 2015 | Rough-Polished | Angolan police seize 9000 cts of diamond in Luvo northern Zaire Province. | rough-polished.com, Apr. 15, 1/4p. | Africa, Angola | News item - legal |
DM201505-0966 2015 | Rough-Polished | SA diamond trader steals diamonds worth $ 1 million. | rough-polished.com, Apr. 15, 1/4p. | Africa, South Africa | News item - legal |
DM201505-0967 2015 | Rough-Polished | Alrosa considers 2014 exploration performance.. All targets successfully achieved. | rough-polished.com, Apr. 17, 1/4p. | Russia | News item - Alrosa |
DM201505-0968 2015 | Rough-Polished | Debswana to cease production at Botswana's first diamond mine, pit drying. 1977 Lethalkane | rough-polished.com, Apr. 16, 1/4p. | Africa, Botswana | News item - Debswana |
DM201505-0969 2015 | Rough-Polished | New record for lab grown diamonds set in Russia. Type Iia using HPHT | rough-polished.com, Apr. 20, 1/4p. | Russia | News item - New Diamond Technology |
DM201505-0970 2015 | Rough-Polished | Kristall plans to buy rough diamonds worth RUB 330 million in May. | rough-polished.com, Apr. 17, 1/4p. | Russia | News item - Kristall |
DM201505-0971 2015 | Rough-Polished | Moody's upgrades Alrosa's CFR to Ba2 stable outlook. | rough-polished.com, Apr. 22, 1/4p. | Russia | News item - Alrosa |
DM201505-0972 2015 | Rough-Polished | Alrosa seeks to operate in Dubai due to its proximity to India. | rough-polished.com, Apr. 22, 1/4p. | Russia | News item - Alrosa |
DM201505-0973 2015 | Rough-Polished | Rio Tinto - Argyle's production Q1 2015 up 31%. | rough-polished.com, Apr. 22, 1/4p. | Australia | News item - Rio Tinto |
DM201505-0974 2015 | Rough-Polished | Stellar produces 5000 carats from Baoule kimberlite trial mining grade of 13.5 cpht. | rough-polished.com, Apr. 22, 1/4p. | Africa, Guinea | News item - Stellar |
DM201505-0975 2015 | Rough-Polished | Andrev Zharkov appointed as President of Alrosa. | rough-polished.com, Apr. 23, 1/4p. | Russia | News item - Alrosa |
DM201505-0976 2015 | Rough-Polished | De Beers Q1 output up 2%, revises full year guidance downwards. | rough-polished.com, Apr. 23, 1/4p. | Global | News item - De Beers |
DM201506-1157 2015 | Rough-Polished | Alrosa's net profit under RAS up 2.9 times in Q1. | rough-polished.com, Apr. 24, 1/4p. | Russia | News item - Alrosa |
DM201506-1158 2015 | Rough-Polished | Alrosa's supervisory board proposes dividend payments for 2014. | rough-polished.com, Apr. 24, 1/4p. | Russia | News item - Alrosa |
DM201506-1159 2015 | Rough-Polished | Global rough diamond output increased to 131.5 m ct in 2014 - research firm. | rough-polished.com, May 22, 1/4p. | Global | News item - markets |
DM201506-1160 2015 | Rough-Polished | DMCC Tradeflow launches 'loans for diamonds'. | rough-polished.com, May 22, 1/4p. | Technology | News item - DMCC |
DM201506-1161 2015 | Rough-Polished | Zim diamond centre installs new machinery, cuts 100-700 stones a day. | rough-polished.com, Apr. 29, 1/4p. | Africa, Zimbabwe | News item - cutting |
DM201506-1162 2015 | Rough-Polished | Botswana not willing to compromise government revenue from rough diamond sales. | rough-polished.com, Apr. 29, 1/4p. | Africa, Botswana | News item - economics |
DM201506-1163 2015 | Rough-Polished | De Beers may put up $ 1 billion worth of rough for sale at its May sight. | rough-polished.com, Apr. 28, 1/4p. | Global | News item - sight |
DM201506-1164 2015 | Rough-Polished | Alrosa to consider reduction of operating costs by 2-3% annually. | rough-polished.com, May 5, 1/4p. | Russia | News item - Alrosa |
DM201506-1165 2015 | Rough-Polished | Debmarine Namibia gets $ 195 million for new sampling, exploration vessel. | rough-polished.com, May, 5, 1/4p. | Africa, Namibia | News item - Debmarine |
DM201506-1166 2015 | Rough-Polished | Zimbabwe provisionally suspends tax on diamond sales. 15% | rough-polished.com, May 5, 1/4p. | Africa, Zimbabwe | News item - legal |
DM201506-1167 2015 | Rough-Polished | Diamcor pockets $ 5 mliion in revenue from SA project since 2013. Krone-Endora | rough-polished.com, May 5, 1/4p. | Africa, South Africa | News item - Diamcor |
DM201506-1168 2015 | Rough-Polished | North Arrow reports final recovery of 384 carats from Qilalugaq bulk sample. | rough-polished.com, May 8, 1/4p. | Canada, Northwest Territories | News item - North Arrow |
DM201506-1169 2015 | Rough-Polished | De Beers cuts diamond prices at latest sale - report. 3% | rough-polished.com, May 7, 1/4p. | Global | News item - De Beers |
DM201506-1170 2015 | Rough-Polished | Proposed Zim diamond merger "costly" - report. | rough-polished.com, May 7, 1/4p. | Africa, Zimbabwe | News item - legal |
DM201506-1171 2015 | Rough-Polished | Alrosa recovered large diamond weighing 76.07 carats at Concentrating factory No. 14, Aikal. | rough-polished.com, May 6, 1/4p. | Russia | News item - Alrosa |
DM201506-1172 2015 | Rough-Polished | Diamond Corp to start mining at Lace in second half of the year. | rough-polished.com, May 6, 1/4p. | Africa, South Africa | News item - DiamondCorp |
DM201506-1173 2015 | Rough-Polished | Fusion/Hennig to sell 30 carat ' Kimberley Purple' from Superkolong tailings plant. | rough-polished.com, May 6, 1/4p. | Africa, South Africa | News item - Batia |
DM201506-1174 2015 | Rough-Polished | Shore Gold commences large diamond drilling at Orion South. | rough-polished.com, May 15, 1/4p. | Canada, Saskatchewan | News item - Shore Gold |
DM201506-1175 2015 | Rough-Polished | Indian diamond industry to adopt more secure business systems. | rough-polished.com, May 14, 1/4p. | India | News item - legal |
DM201506-1176 2015 | Rough-Polished | De Beers acquires stake in Synova. Laser micro jet technology. | rough-polished.com, May 14, 1/4p. | Technology | News item - Synova |
DM201506-1177 2015 | Rough-Polished | Mbada Diamonds fires 240 workers following strike. | rough-polished.com, May 14, 1/4p. | Africa, Zimbabwe | News item - Mbada |
DM201506-1178 2015 | Rough-Polished | Marange Resources hit by $ 178 k lawsuit ( transport company) | rough-polished.com, May 13, 1/4p. | Africa, Zimbabwe | News item - Marange |
DM201506-1179 2015 | Rough-Polished | Antwerp stregthens ties with Canadian miners. Renard | rough-polished.com, May 13, 1/4p. | Canada, Quebec | News item - Stornoway |
DM201506-1180 2015 | Rough-Polished | Alrosa gets Eyekitsky 31 million carat licence. | rough-polished.com, May 15, 1/4p. | Russia, Yakutia | News item - Alrosa |
DM201506-1181 2015 | Rough-Polished | WFDB to discuss diamond overgrading at Presidents meeting next month. | rough-polished.com, May 19, 1/4p. | Technology | News item - WFDB |
DM201506-1182 2015 | Rough-Polished | SA State diamond trader under fire. | rough-polished.com, May 19, 1/4p. | Africa, South Africa | News item - SDT |
DM201506-1183 2015 | Rough-Polished | Petra Diamonds, SA workers union reach entrenchment deal. | rough-polished.com, May 19, 1/4p. | Africa, South Africa | News item - Petra |
DM201506-1184 2015 | Rough-Polished | Zimbabwe conducts third local diamond auction. | rough-polished.com, May 18, 1/4p. | Africa, Zimbabwe | News item - auction |
DM201506-1185 2015 | Rough-Polished | IDE outlines actions following GIA alert on treated diamonds. | rough-polished.com, May 20, 1/4p. | Technology | News item - IDE |
DM201506-1186 2015 | Rough-Polished | Sri Lanka to enter Botswana diamond market. | rough-polished.com, May 20, 1/4p. | Africa, Botswana | News item - markets |
DM201506-1187 2015 | Rough-Polished | Zim now "experienced" in diamond trading. | rough-polished.com, May 21, 1/4p. | Africa, Zimbabwe | News item - sales |
DM201506-1188 2015 | Rough-Polished | Lucapa rakes in $ 2.3 million from Lulo's fourth diamond sale. | rough-polished.com, May 22, 1/4p. | Africa, Angola | News item - Lucapa |
DM201506-1189 2015 | Rough-Polished | Diacam360 to debut at upcoming JCK Las Vegas show. High quality photos and 360 degree videos. | rough-polished.com, May 22, 1/4p. | Technology | News item - Diacam360 |
DM201506-1190 2015 | Rough-Polished | Analysts: Alrosa may reduce diamond prices by 2-3% in May. | rough-polished.com, May 21, 1/4p. | Russia | News item - Alrosa |
DM201506-1191 2015 | Rough-Polished | Dominion Diamond's 1 Q rough diamond sales up 7 %. | rough-polished.com, May 26, 1/4p. | Canada, Northwest Territories | News item - Domion |
DM201506-1192 2015 | Rough-Polished | Lukfook Group signs three year sightholder sales contract with De Beers. | rough-polished.com, May 26, 1/4p. | China | News item - De Beers |
DM201506-1193 2015 | Rough-Polished | Alrosa unearths large diamond weighing 78 carats. Mir | rough-polished.com, May 25, 1/4p. | Russia | News item - Alrosa |
DM201506-1194 2015 | Rough-Polished | Gem Diamonds declares maiden dividend. Letseng, Ghaghoo | rough-polished.com, May 25, 1/4p. | Africa, Lesotho, Botswana | News item - GEM Diamonds |
DM201506-1195 2015 | Rough-Polished | Trans Hex reports higher earnings. | rough-polished.com, May 27, 1/4p. | Africa, Angola, South Africa | News item - Trans Hex |
DM201507-1196 2015 | Rough-Polished | Head of Yakutia and Alrosa president held a joint meeting. | rough-polished.com, May 28, 1/4p. | Russia | News item - Alrosa |
DM201507-1197 2015 | Rough-Polished | Diamond Corp loss widens, mining starts at Lace mine. | rough-polished.com, May 28, 1/4p. | Africa, South Africa | News item - DiamondCorp |
DM201507-1198 2015 | Rough-Polished | Lucara readies for first exceptional stone tender in Botswana. | rough-polished.com, May 28, 1/4p. | Africa, Botswana | News item - Lucara |
DM201507-1199 2015 | Rough-Polished | New Namibia, De Beers sales agreement to come into force next month. | rough-polished.com, May 28, 1/4p. | Africa, Namibia | News item - De Beers |
DM201507-1200 2015 | Rough-Polished | Changes are shaping the world's diamond market. | rough-polished.com, May 28, 1/4p. | Global | News item - markets |
DM201507-1201 2015 | Rough-Polished | What it will take for the synthetic diamond industry to be ( un) successful. | rough-polished.com, May 27, 1/4p. | Technology | News item - synthetics |
DM201507-1202 2015 | Rough-Polished | VIP diamond buyers resist De Beers pricing that boosted profits. | rough-polished.com, May 26, 1/4p. | Global | News item - De Beers |
DM201507-1203 2015 | Rough-Polished | Peregrine Diamonds Ltd. Joined the Diamond Bourse of Canada and is being represented by Dr. Jennifer Pell. | rough-polished.com, May 27, 1/4p. | Canada | News item - Peregrine |
DM201507-1204 2015 | Rough-Polished | JPMorgan reduces Alrosa shares rating to 'hold', raises forecast cost by 66%. | rough-polished.com, May 29, 1/4p. | Russia | News item - Alrosa |
DM201507-1205 2015 | Rough-Polished | Sight okay, retail not at all. | rough-polished.com, May 29, 1p. | Global | News item - prices |
DM201507-1206 2015 | Rough-Polished | India's SNZ for rough trading to become operation from 1st July. | rough-polished.com, June 2, 1/4p. | India | News item - SNZ |
DM201507-1207 2015 | Rough-Polished | Brazil Minerals completes first phase of new diamond & gold area geological assessment. | rough-polished.com, June 2, 1/4p. | South America, Brazil | News item - Brazil Minerals |
DM201507-1208 2015 | Rough-Polished | S & P confirmed Alrosa's rating, improved the outlook to positive. | rough-polished.com, June 1, 1/4p. | Russia | News item - Alrosa |
DM201507-1209 2015 | Rough-Polished | Abbey Chikane's prescription on diamond beneficiation in southern Africa. | rough-polished.com, June 1, 1p. | Africa | News item - KP |
DM201507-1210 2015 | Rough-Polished | Alrosa to repay $ 1 Bln of debt in autumn ahead of schedule. | rough-polished.com, June 4, 1/4p. | Russia | News item - Alrosa |
DM201507-1211 2015 | Rough-Polished | De Beers 2014 rough diamond sales for beneficiation in host countries up 11%. | rough-polished.com, June 4, 1/4p. | Global | News item - De Beers |
DM201507-1212 2015 | Rough-Polished | Yakutia lowers target figures for gold mining, diamond manufacturing. | rough-polished.com, June 4, 1/4p. | Russia | News item - Yakutia |
DM201507-1213 2015 | Rough-Polished | Scio Diamond teams with Helzberg to test demand for lab-grown diamonds. | rough-polished.com, June 4, 1/4p. | Technology | News item - Scio Diamond |
DM201507-1214 2015 | Rough-Polished | Botswana Resource sector conference roars into life. | rough-polished.com, June 9, 1/4p. | Africa, Botswana | News item - economics |
DM201507-1215 2015 | Rough-Polished | DTZ-OZGEO ordered to suspend diamond mining. | rough-polished.com, June 8, 1/4p. | Africa, Zimbabwe | News item - DTZ-OZGEO |
DM201507-1216 2015 | Rough-Polished | Botswana Diamonds says new Diamondiferous kimberlite expected by year-end. ( Orapa region) | rough-polished.com, June 11, 1/4p. | Africa, Botswana | News item - Botswana Diamonds |
DM201507-1217 2015 | Rough-Polished | Rough, polished diamond prices mismatch driving demand downwards - Botswana minister. | rough-polished.com, June 11, 1/4p. | Africa, Botswana | News item - prices |
DM201507-1218 2015 | Rough-Polished | Debswana says not worried about synthetic diamonds. | rough-polished.com, June 11, 1/4p. | Africa, Botswana | News item - Debswana |
DM201507-1219 2015 | Rough-Polished | DTZ-OZGEO never stopped diamond mining operations in Zimbabwe. | rough-polished.com, June 10, 1/4p. | Africa, Zimbabwe | News item - DTZ-OZGEO |
DM201507-1220 2015 | Rough-Polished | SA senior diamond valuator fired for probing De Beers - report. | rough-polished.com, June 10, 1/4p. | Africa, South Africa | News item - De Beers |
DM201507-1221 2015 | Rough-Polished | Alrosa president to attend 2015 president's meeting … World Federation of Diamond Bourses. | rough-polished.com, June 9, 1/4p. | Russia | News item - Alrosa |
DM201507-1222 2015 | Rough-Polished | Mustang Resources recovers diamonds in Mozambique. Save River | rough-polished.com, June 18, 1/4p. | Africa, Mozambique | News item - Mustang |
DM201507-1223 2015 | Rough-Polished | Botswana invites bids for new Orapa diamond licences. | rough-polished.com, June 18, 1/4p. | Africa, Botswana | News item - legal |
DM201507-1224 2015 | Rough-Polished | Petra expects FY revenue to top $ 430 m. | rough-polished.com, June 17, 1/4p. | Africa, South Africa | News item - Petra |
DM201507-1225 2015 | Rough-Polished | Museum of Named Diamonds opens to focus on 'Diamond Story'. [email protected] | rough-polished.com, June 17, 1/4p. | Global | News item - diamonds notable |
DM201507-1226 2015 | Rough-Polished | Botswana Diamonds, Alrosa JV identify 'strong' anomaly on Orapa prospecting licence. | rough-polished.com, June 19, 1/4p. | Africa, Botswana | News item - Botswana Diamonds, Alrosa |
DM201507-1227 2015 | Rough-Polished | De Beers rakes in $ 550 m from June sight. | rough-polished.com, June 19, 1/4p. | Global | News item - De Beers |
DM201507-1228 2015 | Rough-Polished | Local community stopped Alrosa's alluvial diamond mining at Malaya Kuonapka. | rough-polished.com, June 18, 1/4p. | Russia, Yakutia | News item - Alrosa |
DM201507-1229 2015 | Rough-Polished | Alrosa announces a RUB bn bond repayment. | rough-polished.com, June 24, 1/4p. | Russia | News item - Alrosa |
DM201507-1230 2015 | Rough-Polished | Graff unveils 132 carat Golden Empress yellow diamond. From Letseng | rough-polished.com, June 24, 1/4p. | Africa, Lesotho | News item - diamonds notable |
DM201507-1231 2015 | Rough-Polished | DDRC finds no synthetic diamond on screening. | rough-polished.com, June 24, 1/4p. | India | News item - DDRC |
DM201507-1232 2015 | Rough-Polished | New head of Alrosa says no need to change the company's strategy. | rough-polished.com, June 23, 1/4p. | Russia | News item - Alrosa |
DM201507-1233 2015 | Rough-Polished | Tsodilo subsidiary Bosoto takes possession of diamonds recovered from BK16. | rough-polished.com, June 23, 1/4p. | Africa, Botswana | News item - Tsodilo |
DM201507-1234 2015 | Rough-Polished | Trying to fix supply driven diamond pipeline instead of generating demand. | rough-polished.com, June 24, 1/4p. | Global | News item - pipeline |
DM201507-1235 2015 | Rough-Polished | It's time to regulate - and rename - lab grown diamonds. | rough-polished.com, June 23, 1/4p. | Technology | News item - synthetics |
DM201507-1236 2015 | Rough-Polished | Alrosa held annual general meeting of shareholders in Mirny. | rough-polished.com, June 25, 1/4p. | Russia | News item - Alrosa |
DM201507-1237 2015 | Rough-Polished | Alrosa to increase revenue by 30% in 2015 through exports. | rough-polished.com, June 25, 1/4p. | Russia | News item - Alrosa |
DM201507-1238 2015 | Rough-Polished | De Beers yields to Namibia's demands - report. | rough-polished.com, June 25, 1/4p. | Africa, Namibia | News item - De Beers |
DM201507-1239 2015 | Rough-Polished | Kennady announces Kelvin sample grade of 2.74 carats per tonne. | rough-polished.com, June 25, 1/4p. | Canada, Northwest Territories | News item - Kennady |
DM201507-1240 2015 | Rough-Polished | Zim not relenting on diamond merger. | rough-polished.com, June 25, 1/4p. | Africa, Zimbabwe | News item - legal |
DM201508-1241 2015 | Rough-Polished | New proposals for Alrosa's strategy may follow - Galushka. | rough-polished.com, June 29, 1/4p. | Russia | News item - Alrosa |
DM201508-1242 2015 | Rough-Polished | KP leaders stress consensus and bringing CAR, Venezuela back into compliance. | rough-polished.com, June 29, 1/4p. | Africa, Central African Republic, South America, Venezuela | News item - KP |
DM201508-1243 2015 | Rough-Polished | Paragon Diamonds loss widens. | rough-polished.com, June 29, 1/4p. | Africa, Lesotho | News item - Paragon |
DM201508-1244 2015 | Rough-Polished | Over the long term, we can expect to see supply shortfall and rising prices. | rough-polished.com, June 29, 1p. | Global | News item - prices |
DM201508-1245 2015 | Rough-Polished | Argyle pink diamonds tender world preview at Sydney Opera House. | rough-polished.com, June 29, 1/4p. | Australia | News item - Argyle |
DM201508-1246 2015 | Rough-Polished | World's first electronic diamond exchange of Singapore to become operational in September. | rough-polished.com, July 3, 1/4p. | Asia, Singapore | News item - DIE |
DM201508-1247 2015 | Rough-Polished | Ellendale diamond mines goes into unexpected voluntary administration. | rough-polished.com, July 3, 1/4p. | Australia | News item - Ellendale |
DM201508-1248 2015 | Rough-Polished | Namibia establishing new sales and marketing company. | rough-polished.com, July 3, 1/4p. | Africa, Namibia | News item - legal |
DM201508-1249 2015 | Rough-Polished | CAR to resume rough exports following KPCS's plan | rough-polished.com, July 2, 1/4p. | Africa, Central African Republic | News item - KP |
DM201508-1250 2015 | Rough-Polished | Alrosa president visits Angola. | rough-polished.com, July 2, 1/4p. | Africa, Angola | News item - Alrosa |
DM201508-1251 2015 | Rough-Polished | Rockwell Diamonds says Q1 was very challenging. | rough-polished.com, July 2, 1/4p. | Africa, South Africa | News item - Rockwell |
DM201508-1252 2015 | Rough-Polished | Kimberley Diamonds secures over $ 7 m to re-commision Botswana mine. Lerala | rough-polished.com, July 1, 1/4p. | Africa, Botswana | News item - Kimberley |
DM201508-1253 2015 | Rough-Polished | Lucapa, partners seek to double diamond operations in Angola. | rough-polished.com, July 1, 1/4p. | Africa, Angola | News item - Lucapa |
DM201508-1254 2015 | Rough-Polished | Australia to withdraw candidacy for KP vice chair. | rough-polished.com, July 2, 1/4p. | Australia | News item - KP |
DM201508-1255 2015 | Rough-Polished | Pangolin identifies anomalous kimberlite indicator minerals at Botswana project, Malatswae | rough-polished.com, July 2, 1/4p. | Africa, Botswana | News item - Pangolin |
DM201508-1256 2015 | Rough-Polished | Monsoon floods damage diamond polishing units in Gujarat. | rough-polished.com, July 2, 1/4p. | India | News item - Gujarat |
DM201508-1257 2015 | Rough-Polished | Renaissance Capital downgrades Alrosa's shares to sell and estimates them at $ 1.04. | rough-polished.com, July 1, 1/4p. | Russia | News item - Alrosa |
DM201508-1258 2015 | Rough-Polished | Alrosa to up investment in Angola. | rough-polished.com, July 3, 1/4p. | Africa, Angola | News item - Alrosa |
DM201508-1259 2015 | Rough-Polished | Ellendale diamond mines goes into unexpected voluntary administration. | rough-polished.com, July 3, 1/4p. | Australia | News item - Ellendale |
DM201508-1260 2015 | Rough-Polished | The three tipping points of Man-made diamonds. | rough-polished.com, July 8, 1/4p. | Technology | News item - synthetics |
DM201508-1261 2015 | Rough-Polished | Mountain Province's Gahcho Kue diamond mine 62 percent complete. | rough-polished.com, July 8, 1/4p. | Canada, Northwest Territories | News item - Mountain Province |
DM201508-1262 2015 | Rough-Polished | SA workers union against De Beers' planned sale of Kimberley Mines. | rough-polished.com, July 8, 1/4p. | Africa, South Africa | News item - legal |
DM201508-1263 2015 | Rough-Polished | Gems One rolls out the new 101 facet diamond cut. | rough-polished.com, July 8, 1/4p. | Technology | News item - Epic 101 |
DM201508-1264 2015 | Rough-Polished | Commentary by John Teeling 'I would like to hold on to something commercial'. | rough-polished.com, July 6, 1p. | Africa, Botswana | News item - Botswana Diamonds |
DM201508-1265 2015 | Rough-Polished | Indian diamond industry decides on 'no embargo on rough import'; suggests 'self-discipline'. | rough-polished.com, July 8, 1/4p. | India | News item - BDB, MDMA |
DM201508-1266 2015 | Rough-Polished | Yakutia produced 10.8% more diamonds in H1. | rough-polished.com, July 10, 1/4p. | Russia, Yakutia | News item - Alrosa |
DM201508-1267 2015 | Rough-Polished | RBZ subsidiary eyes $ 1 million for equipment to beneficiate diamonds. | rough-polished.com, July 10, 1/4p. | Africa, Zimbabwe | News item - Reserve Bank |
DM201508-1268 2015 | Rough-Polished | British Embassy says Zim diamond industry 'politically sensitive'. | rough-polished.com, July 10, 1/4p. | Africa, Zimbabwe | News item - legal |
DM201508-1269 2015 | Rough-Polished | Golden Saint Resources recovers 100 carats from bulk sampling in Sierra Leone. | rough-polished.com, July 10, 1/4p. | Africa, Sierra Leone | News item - Golden Saint |
DM201508-1270 2015 | Rough-Polished | Belgian police are investigating illegal supply of diamonds from Africa. | rough-polished.com, July 14, 1/4p. | Europe, Belgium | News item - legal |
DM201508-1271 2015 | Rough-Polished | Paragon signs legally binding agreement to acquire Mothae. | rough-polished.com, July 15, 1/4p. | Africa, Lesotho | News item - Paragon |
DM201508-1272 2015 | Rough-Polished | Lucara's exceptional stone tender. Karowe rakes in $ 69 Million. | rough-polished.com, July 20, 1/4p. | Africa, Botswana | News item - Lucara |
DM201508-1273 2015 | Rough-Polished | Riozim assures workers, community of its commitment to Murowa diamonds. | rough-polished.com, July 20, 1/4p. | Africa, Zimbabwe | News item - RioZim |
DM201508-1274 2015 | Rough-Polished | Tsodilo adopts new exploration geological model. | rough-polished.com, July 17, 1/4p. | Africa, Botswana | News item - Tsodilo |
DM201508-1275 2015 | Rough-Polished | Kennady announces Faraday 2 diamond recovery results. | rough-polished.com, July 17, 1/4p. | Canada, Northwest Territories | News item - Kennady |
DM201508-1276 2015 | Rough-Polished | Alrosa reports H1 production and trading performance. | rough-polished.com, July 21, 1/4p. | Russia | News item - Alrosa |
DM201508-1277 2015 | Rough-Polished | Zim's Murowa Diamonds output dips in H1. ( 50% drop in the first half of year). | rough-polished.com, July 21, 1/4p. | Africa, Zimbabwe | News item - Rio Tinto |
DM201508-1278 2015 | Rough-Polished | Pangolin finds abundant "positive" kimberlitic ilmentes at Malatswae. | rough-polished.com, July 21, 1/4p. | Africa, Botswana | News item - Pangolin |
DM201508-1279 2015 | Rough-Polished | Peregrine acquires Botswana diamond company. Diamexstrat | rough-polished.com, July 21, 1/4p. | Africa, Botswana | News item - Peregrine |
DM201508-1280 2015 | Rough-Polished | Rio's Argyle diamond production up; Diavik flat. | rough-polished.com, July 20, 1/4p. | Australia, Canada, Northwest Territories | News item - Rio Tinto |
DM201508-1281 2015 | Rough-Polished | De Beers July sight realizes $ 200m as buyers reject goods. | rough-polished.com, July 22, 1/4p. | Global | News item - De Beers |
DM201508-1282 2015 | Rough-Polished | Diamcor rakes in over $ 450K from SA Q1 diamond sales. | rough-polished.com, July 22, 1/4p. | Africa, South Africa | News item - Diamcor |
DM201508-1283 2015 | Rough-Polished | Kimberley okays Lerala mining restart. | rough-polished.com, July 22, 1/4p. | Africa, Botswana | News item - Kimberley Diamonds |
DM201508-1284 2015 | Rough-Polished | DTZ-OZGEO is steadily increasing production and exploration. | rough-polished.com, July 22, 1/4p. | Africa, Zimbabwe | News item - DTZ-OZGEO |
DM201508-1285 2015 | Rough-Polished | Tawana says BlueRock still interested in diamond resource. Kareevlei | rough-polished.com, July 23, 1/4p. | Africa, South Africa | News item - Tawana |
DM201508-1286 2015 | Rough-Polished | Alrosa increased net profit under RAS by 1.6 times. | rough-polished.com, July 23, 1/4p. | Russia | News item - Alrosa |
DM201508-1287 2015 | Rough-Polished | Alfa-bank has lowered the estimate of Alosa's shares to 100 rubles. Maintain buy recommendation. | rough-polished.com, July 23, 1/4p. | Russia | News item - Alrosa |
DM201508-1288 2015 | Rough-Polished | De Beers reviews 2015 production guidance, H1 sales weaken. | rough-polished.com, July 24, 1/4p. | Global | News item - De Beers |
DM201508-1289 2015 | Rough-Polished | IDE holds symposium to discuss main issues facing the diamond industry. | rough-polished.com, July 24, 1/4p. | Global | News item - IDE |
DM201508-1290 2015 | Rough-Polished | Marange villagers accuse Zim environment agency of inaction as diamond miners destroy environment. | rough-polished.com, July 24, 1/4p. | Africa, Zimbabwe | News item - CSR |
DM201508-1291 2015 | Rough-Polished | Alrosa completes open-pit mining at Udachnaya pipe. | rough-polished.com, July 27, 1/4p. | Russia, Yakutia | News item - Alrosa |
DM201508-1292 2015 | Rough-Polished | Shortening the supply pipeline is a unique feature of the International Diamond Week in Israel. | rough-polished.com, July 27, 1/4p. | Global | News item - pipeline |
DM201509-1293 2015 | Rough-Polished | Alrosa announces a $ 85 mln bank loan repayment. | rough-polished.com, July 29, 1/4p. | Russia | News item - Alrosa |
DM201509-1294 2015 | Rough-Polished | De Beers says buyers can defer up to 75% of allocated rough at August sight. | rough-polished.com, July 29, 1/4p. | Global | News item - De Beers |
DM201509-1295 2015 | Rough-Polished | Diamond Corp frustrated by kimberlite development at Lace. | rough-polished.com, Aug. 4, 1/4p. | Africa, South Africa | News item - DiamondCorp |
DM201509-1296 2015 | Rough-Polished | Mwana Africa restarts SA underground mining . Klipspringer | rough-polished.com, Aug. 4, 1/4p. | Africa, South Africa | News item - Mwana |
DM201509-1297 2015 | Rough-Polished | KP to brief UN on decision to allow CAR resume diamond exports in compliant zones. | rough-polished.com, Aug. 3, 1/4p. | Africa, Central African Republic | News item - KP |
DM201509-1298 2015 | Rough-Polished | Petra boosts diamond output. Wiliamson | rough-polished.com, July 31, 1/4p. | Africa, Tanzania | News item - Petra |
DM201509-1299 2015 | Rough-Polished | British MP: the Kohinoor diamond should be returned to India. | rough-polished.com, July 31, 1/4p. | India | News item - diamonds notable |
DM201509-1300 2015 | Rough-Polished | Gye Nyame creditors seek to restart defunct mine despite Zim diamond mines consolidation plans. Marange | rough-polished.com, Aug. 4, 1/4p. | Africa, Zimbabwe | News item - Gye Nyame |
DM201509-1301 2015 | Rough-Polished | Angola's H1 diamond sales up 35% to $ 573m. | rough-polished.com, Aug. 5, 1/4p. | Africa, Angola | News item - Endiama |
DM201509-1302 2015 | Rough-Polished | Blue Star to offer 200 lots in polished diamond tender. | rough-polished.com, Aug. 5, 1/4p. | Global | News item - Blue Star |
DM201509-1303 2015 | Rough-Polished | GIA bars Indian company for fraudulent report inscription. | rough-polished.com, Aug. 5, 1/4p. | India | News item - Cristy Gems |
DM201509-1304 2015 | Rough-Polished | Diamond prices, sentiment slump in July. | rough-polished.com, Aug. 6, 1/4p. | Global | News item - prices |
DM201509-1305 2015 | Rough-Polished | Severalmaz reduces loss under RAS 2,4 times. | rough-polished.com, Aug. 11, 1/4p. | Russia | News item - Alrosa |
DM201509-1306 2015 | Rough-Polished | Angola imposes moratorium on issuing mining licences. | rough-polished.com, Aug. 11, 1/4p. | Africa, Angola | News item - legal |
DM201509-1307 2015 | Rough-Polished | Angola extends Lulo diamond mining concession. | rough-polished.com, Aug. 11, 1/4p. | Africa, Angola | News item - Lucapa |
DM201509-1308 2015 | Rough-Polished | Sarine's revenue declines significantly in Q2 2015 year on year on the back of challenging industry conditions. | rough-polished.com, Aug. 11, 1/4p. | Technology | News item - Sarine |
DM201509-1309 2015 | Rough-Polished | Gemfields eyes 30% market share in India. | rough-polished.com, Aug. 10, 1/4p. | India | News item - Gemfields |
DM201509-1310 2015 | Rough-Polished | Telangana sitting on a bed of diamonds. | rough-polished.com, Aug. 12, 1/4p. | India | News item - Mahbubnagar |
DM201509-1311 2015 | Rough-Polished | Zim establishes diamond cleaning facility. | rough-polished.com, Aug. 12, 1/4p. | Africa, Zimbabwe | News item - laboratory |
DM201509-1312 2015 | Rough-Polished | Our business is built on trust and confidence is critical. | rough-polished.com, Aug. 10, 1/4p. | Global | News item - legal |
DM201509-1313 2015 | Rough-Polished | Namibia aiming for Botswana style diamond deal with De Beers. | rough-polished.com, Aug. 9, 1/4p. | Africa, Namibia | News item - Debswana |
DM201509-1314 2015 | Rough-Polished | The new diamond capital… India. | rough-polished.com, Aug. 11, 1/4p. | India | News item - Polishing |
DM201509-1315 2015 | Rough-Polished | Lucara Q2 revenue up to $ 38m, completes Botswana plant optimisation project. Karowe | rough-polished.com, Aug. 13, 1/4p. | Africa, Botswana | News item - Lucara |
DM201509-1316 2015 | Rough-Polished | Morgan Stanley kept the recommendation to buy Alrosa's shares. | rough-polished.com, Aug. 12, 1/4p. | Russia | News item - Alrosa |
DM201509-1317 2015 | Rough-Polished | Sierra Leone alluvial diamond deposits exhausted. | rough-polished.com, Aug. 14, 1/4p. | Africa, Sierra Leone | News item - alluvials |
DM201509-1318 2015 | Rough-Polished | De Beers granted new licences in Botswana, SA. | rough-polished.com, Aug. 17, 1/4p. | Africa, Botswana | News item - De Beers |
DM201509-1319 2015 | Rough-Polished | Pangolin optomistic of finding diamonds in Botswana. Profile by Leon Daniels on Malatswae project. | rough-polished.com, Aug. 17, 1p. | Africa, Botswana | News item - Pangolin. |
DM201509-1320 2015 | Rough-Polished | Botswana seen facing budget deficit as diamond sales fall. | rough-polished.com, Aug. 18, 1/4p. | Africa, Botswana | News item - legal |
DM201509-1321 2015 | Rough-Polished | In Antwerp there are only 500 diamond cutters left. | rough-polished.com, Aug. 18, 1/4p. | Europe, Belgium | News item - cutters |
DM201509-1322 2015 | Rough-Polished | Carnage in diamond cutting industry. | rough-polished.com, Aug. 18, 1/4p. | Global | News item - cutters |
DM201509-1323 2015 | Rough-Polished | Anglo switch an emblem of industry in reverse. | rough-polished.com, Aug. 17, 1/4p. | Global | News item - Anglo |
DM201509-1324 2015 | Rough-Polished | India's diamond market events in July 2015. | rough-polished.com, Aug. 17, 1p. | India | News item - markets |
DM201509-1325 2015 | Rough-Polished | GSI in Surat begins to bulk batch testing of Stars and Melees. | rough-polished.com, Aug. 20, 1/4p. | India | News item - GSI |
DM201509-1326 2015 | Rough-Polished | Zimbabwe projects drop in mining production as reserves decline. | rough-polished.com, Aug. 20, 1/4p. | Africa, Zimbabwe | News item - Marange |
DM201509-1327 2015 | Rough-Polished | Stornoway will begin full-scale production at the Renard mine in mid 2017. | rough-polished.com, Aug. 19, 1/4p. | Canada, Quebec | News item - Stornoway |
DM201509-1328 2015 | Rough-Polished | Stellar raises $ 300 k for group working capital. Baoue | rough-polished.com, Aug. 19, 1/4p. | Africa, Guinea | News item - Stellar |
DM201509-1329 2015 | Rough-Polished | Diamond firm slapped with UN sanctions for CAR illegal trading. Kardiam ( Badica). | rough-polished.com, Aug. 24, 1/4p. | Africa, Central African Republic | News item - Kardiam |
DM201509-1330 2015 | Rough-Polished | Soft diamond prices force Botswana to cut growth to 2.5%. | rough-polished.com, Aug. 24, 1/4p. | Africa, Botswana | News item - prices |
DM201509-1331 2015 | Rough-Polished | De Beers program distributes books to communities near Snap Lake and Victor. | rough-polished.com, Aug. 24, 1/4p. | Canada, Northwest Territories, Ontario | News item - CSR |
DM201509-1332 2015 | Rough-Polished | Alrosa reduced diamond sale in August, but did not amend prices. | rough-polished.com, Aug. 27, 1/4p. | Russia | News item - Alrosa |
DM201509-1333 2015 | Rough-Polished | Kimberley remains on track for Lerala production start next Feb. | rough-polished.com, Aug. 27, 1/4p. | Africa, Botswana | News item - Kimberley Diamonds |
DM201509-1334 2015 | Rough-Polished | Diamond sales at Mwana's SA mine drop. Klipspringer | rough-polished.com, Aug. 27, 1/4p. | Africa, South Africa | News item - Mwana |
DM201510-2062 2015 | Rough-Polished | De Beers cautiously optimistic for outlook in major consumer markets. | rough-polished.com, Aug. 31, 2p. | Global | News item - De Beers |
DM201510-2063 2015 | Rough-Polished | Alrosa plans to adjust sales plan for H2. | rough-polished.com, Sept. 3, 1/4p. | Russia | News item - Alrosa |
DM201510-2064 2015 | Rough-Polished | Diamond Corp pencils first Lace diamonds sale for Oct. | rough-polished.com, Sept. 3, 1/4p. | Africa, South Africa | News item - DiamondCorp |
DM201510-2065 2015 | Rough-Polished | Smuggling of CAR diamonds into Cameroon, Chad fueling conflict. | rough-polished.com, Sept. 3, 1/4p. | Africa, Central African Republic | News item - CSR |
DM201510-2066 2015 | Rough-Polished | Newly discovered Kamchatka diamond field may contain up to 10 million carats of diamonds. Ozernovo | rough-polished.com, Sept. 3, 1/4p. | Russia | News item - Ozernovo |
DM201510-2067 2015 | Rough-Polished | Antwerp remains most important rough diamond trade hub. | rough-polished.com, Sept. 2, 1/4p. | Europe, Belgium | News item - Antwerp |
DM201510-2068 2015 | Rough-Polished | Alrosa is waiting for diamond trade zone in India to form. | rough-polished.com, Sept. 4, 1/4p. | Russia, India | News item - Alrosa |
DM201510-2069 2015 | Rough-Polished | Alrosa offers Chinese partners to participate in diamond cutting in Vladivorstok. | rough-polished.com, Sept. 4, 1/4p. | Russia, China | News item - Alrosa |
DM201510-2070 2015 | Rough-Polished | Alrosa will not change the overall strategy due to easing of diamond prices. | rough-polished.com, Sept. 4, 1/4p. | Russia | News item - Alrosa |
DM201510-2071 2015 | Rough-Polished | Botswana Diamonds, Alrosa to start drilling, intensive soil sampling in Orapa. | rough-polished.com, Sept. 4, 1/4p. | Africa, Botswana | News item - Botswana Diamonds, Alrosa |
DM201510-2072 2015 | Rough-Polished | Epstein: the potential of the diamond exchange in the Russian Far East is limited. | rough-polished.com, Sept. 4, 1/4p. | Russia | News item - AWDC |
DM201510-2073 2015 | Rough-Polished | Diamond bourse may be created in the Far East in 2016 | rough-polished.com, Sept. 3, 1/4p. | Russia | News item - bourse |
DM201510-2074 2015 | Rough-Polished | Alrosa raised $ 1.13 million during diamond week in Yakutia. | rough-polished.com, Sept. 8, 1/4p. | Russia | News item - Alrosa |
DM201510-2075 2015 | Rough-Polished | Alrosa to sell no more than $ 295m worth of diamonds in Yakutia in 2015. | rough-polished.com, Sept. 8, 1/4p. | Russia | News item - Alrosa |
DM201510-2076 2015 | Rough-Polished | Angola produces over 865 K ct in July, pockets $ 115m. | rough-polished.com, Sept. 7, 1/4p. | Africa, Angola | News item - |
DM201510-2077 2015 | Rough-Polished | Portugal to become 7th KP authority in Europe. | rough-polished.com, Sept. 7, 1/4p. | Europe, Portugal | News item - KP |
DM201510-2078 2015 | Rough-Polished | Alrosa seeks government support for diamond mining at Verkne-Munskoye deposit. | rough-polished.com, Sept. 9, 1/4p. | Russia, Yakutia | News item - Alrosa |
DM201510-2079 2015 | Rough-Polished | Angola's Endiama licences two diamond exploration co-operatives, Nharea Ble province. | rough-polished.com, Sept. 9, 1/4p. | Africa, Angola | News item - Endiama |
DM201510-2080 2015 | Rough-Polished | Catoca's 2014 diamond sales marginally up as output drops. | rough-polished.com, Sept. 10, 1/4p. | Africa, Angola | News item - Catoca |
DM201510-2081 2015 | Rough-Polished | Dharmanand an Research Centre introduces D-Secure for synthetics identification. | rough-polished.com, Sept. 10, 1/4p. | Technology | News item - Synthetics |
DM201510-2082 2015 | Rough-Polished | Mwana raises funds to recommence production at mothballed SA diamond mine. | rough-polished.com, Sept. 11, 1/4p. | Africa, South Africa | News item - Mwana |
DM201510-2083 2015 | Rough-Polished | Gemfields pockets over $ 34 million from Kagem emeralds auction ( Zambia) | rough-polished.com, Sept. 11, 1/4p. | Africa, Zambia | News item - Gemfields |
DM201510-2084 2015 | Rough-Polished | Scio raises $ 1.6 million to fund synthetic diamond development. | rough-polished.com, Sept. 11, 1/4p. | Technology | News item - Scio |
DM201510-2085 2015 | Rough-Polished | Botswana Diamonds, Alrosa start drilling on 3 Orapa prospecting licences. | rough-polished.com, Sept. 14, 1/4p. | Africa, Botswana | News item - Botswana Diamonds, Alrosa |
DM201510-2086 2015 | Rough-Polished | Debswana lowers 2015 diamond output guidance. | rough-polished.com, Sept. 14, 1/4p. | Russia | News item - Alrosa |
DM201510-2087 2015 | Rough-Polished | Rio Tinto to hold special tender for +10.8 carat stones at IDE ( coloured rough too) | rough-polished.com, Sept. 14, 1/4p. | Australia | News item - Rio Tinto |
DM201510-2088 2015 | Rough-Polished | Israel's new AML law for diamond industry goes into effect Sept. 15th Money Laundering law | rough-polished.com, Sept. 14, 1/4p. | Europe, Israel | News item - legal |
DM201510-2089 2015 | Rough-Polished | Kristall intends to sell a replica of the Grand Imperial Crown for 1 bn rubles. | rough-polished.com, Sept. 15, 1/4p. | Russia | News item - Kristall |
DM201510-2090 2015 | Rough-Polished | Lucapa grosses A$ 1 m from Lulo diamond auction. | rough-polished.com, Sept. 15, 1/4p. | Africa, Angola | News item - Lucapa |
DM201510-2091 2015 | Rough-Polished | Paragon ecstatic as study results show potential for average diamond value at Mothae. | rough-polished.com, Sept. 16, 1/4p. | Africa, Lesotho | News item - Paragon |
DM201510-2092 2015 | Rough-Polished | Lucapa recovers more 'large special' diamonds from Angola's Lulo. | rough-polished.com, Sept. 16, 1/4p. | Africa, Angola | News item - Lucapa |
DM201510-2093 2015 | Rough-Polished | Zim's Aurex diamond to be capacitated. … to enhance "high value" polished diamonds. | rough-polished.com, Sept. 18, 1/4p. | Africa, Zimbabwe | News item - Aurex |
DM201510-2094 2015 | Rough-Polished | Petra Diamonds says FY 2015 revenue down 10%. | rough-polished.com, Sept. 21, 1/4p. | Africa, South Africa | News item - Petra |
DM201510-2095 2015 | Rough-Polished | Brazil Minerals's diamond, gold mine receives 4 year environmental license renewal. | rough-polished.com, Sept. 21, 1/4p. | South America, Brazil | News item - Brazil Minerals |
DM201510-2096 2015 | Rough-Polished | Sotheby's to auction 12 carat Blue Moon diamond. | rough-polished.com, Sept. 21, 1/4p. | Global | News item - diamonds notable |
DM201510-2097 2015 | Rough-Polished | De Beers says 2015 a more challenging year. | rough-polished.com, Sept. 22, 1/4p. | Global | News item - De Beers |
DM201510-2098 2015 | Rough-Polished | Rio Tinto's rare red and pink Argyle diamonds shine in Hong Kong. | rough-polished.com, Sept. 22, 1/4p. | Australia | News item - Rio Tinto |
DM201510-2099 2015 | Rough-Polished | Positive indicators for diamond industry ahead of holiday season. WFDB President. | rough-polished.com, Sept. 23, 1/4p. | Global | News item - markets |
DM201510-2100 2015 | Rough-Polished | Lucapa finds two more diamonds weighing over 50 ct at Lulo. | rough-polished.com, Sept. 23, 1/4p. | Africa, Angola | News item - Lucapa |
DM201510-2101 2015 | Rough-Polished | Weak global commodity markets force Rockwell Diamonds to delay equity financing. | rough-polished.com, Sept. 23, 1/4p. | Africa, South Africa | News item - Rockwell |
DM201510-2102 2015 | Rough-Polished | Petra exploration expenditure rises to $ 5.6 million. | rough-polished.com, Sept. 24, 1/4p. | Africa, South Africa | News item - Petra |
DM201510-2103 2015 | Rough-Polished | India stands 3rd only after US & Chin a in diamond consumption. | rough-polished.com, Sept. 24, 1/4p. | India | News item - markets |
DM201510-2104 2015 | Rough-Polished | Firestone receives first drawdown on $ 7.6m for Liqhobong. | rough-polished.com, Sept. 24, 1/4p. | Africa, Lesotho | News item - Firestone |
DM201510-2105 2015 | Rough-Polished | Rio Tinto sees sparkle fade from Chinese diamond demand. | rough-polished.com, Sept. 25, 1/4p. | China | News item - Rio Tinto |
DM201511-2158 2015 | Rough-Polished | De Beers sees great opportunities for diamond industry in India. | rough-polished.com, Sept. 28, 1/4p. | India | News item - De Beers |
DM201511-2159 2015 | Rough-Polished | Amnesty International reports on Blood Diamonds from CAR. | rough-polished.com, Sept. 28, 1/4p. | Africa, Central African Republic | News item - legal |
DM201511-2160 2015 | Rough-Polished | FIMI: India must hike spending on mineral exploration. | rough-polished.com, Sept. 28, 1/4p. | India | News item - FMFI |
DM201511-2161 2015 | Rough-Polished | Ari Epstein, CEO of AWDC: diamond pipeline to unclog and demand to pick up in 2-3 months. | rough-polished.com, Sept. 28, 1p. | Global | News item - AWDC |
DM201511-2162 2015 | Rough-Polished | Angola made great strides as KP chair. | rough-polished.com, Sept. 29, 1/4p. | Africa, Angola | News item - KP |
DM201511-2163 2015 | Rough-Polished | Namibia, De Beers yet to sign diamond sales deal - report. | rough-polished.com, Sept. 30, 1/4p. | Africa, Namibia | News item - De Beers |
DM201511-2164 2015 | Rough-Polished | Lucapa recovers 90.32 ct gem… Mining Block 8 at Lulo. | rough-polished.com, Oct. 1, 1/4p. | Africa, Angola | News item - Lucapa |
DM201511-2165 2015 | Rough-Polished | Paragon Diamonds issues revenues forecast for Lesotho mines. Lemphane and Mothae | rough-polished.com, Oct. 1, 1/4p. | Africa, Lesotho | News item - Paragon |
DM201511-2166 2015 | Rough-Polished | India's BDB ( Bharat Diamond Bourse) in Mumbai has banned the trade in synthetic diamonds effective Otober 1. | rough-polished.com, Oct. 5, 1/4p. | India | News item - synthetics |
DM201511-2167 2015 | Rough-Polished | Amnesty accuses Sodiam of stockpiling CAR conflict diamonds worth $ 7 m. | rough-polished.com, Oct. 5, 1/4p. | Africa, Central African Republic | News item - Sodiam |
DM201511-2168 2015 | Rough-Polished | Paragon Diamonds inks $ 15 m deal for Lesotho mines development. | rough-polished.com, Oct. 5, 1/4p. | Africa, Lesotho | News item - Paragon |
DM201511-2169 2015 | Rough-Polished | Sarine introduced Meteor system for inclusion mapping of smaller stones. | rough-polished.com, Oct. 5, 1/4p. | Technology | News item - Sarine |
DM201511-2170 2015 | Rough-Polished | Tax revenue from diamond sales in the Arkhangelsk region up 4.5 times to 930 million rubles. | rough-polished.com, Oct. 2, 1/4p. | Russia, Kola Peninsula, Archangel | News item - legal |
DM201511-2171 2015 | Rough-Polished | Alrosa to introduce diamond bourse project to Trutnev and Siluanov. | rough-polished.com, Oct. 6, 1/4p. | Russia | News item - bourse |
DM201511-2172 2015 | Rough-Polished | Gokhran bought more than half of polished diamonds required by quota from Kristall. | rough-polished.com, Oct. 6, 1/4p. | Russia | News item - Kristall |
DM201511-2173 2015 | Rough-Polished | The replica of the Great Imperial Crown of the Russian empire is a masterpiece of Russian gem cutters and evidence that they are among the best artisans in the world. | rough-polished.com, Oct. 5, 1p. | Russia | News item - Kristall |
DM201511-2174 2015 | Rough-Polished | Alrosa to implement pillar mining at the Aikhal underground mine. | rough-polished.com, Oct. 7, 1/4p. | Russia | News item - Alrosa |
DM201511-2175 2015 | Rough-Polished | BlueRock Diamonds gets UK 400k to fund SA operations. Kareeviel | rough-polished.com, Oct. 7, 1/4p. | Africa, South Africa | News item - BlueRock |
DM201511-2176 2015 | Rough-Polished | Alrosa extracts another king-size diamond, this time weighing 103 carats. Aikhal | rough-polished.com, Oct. 9, 1/4p. | Russia | News item - Alrosa |
DM201511-2177 2015 | Rough-Polished | Botswana diamond output continues on downward projectory. | rough-polished.com, Oct. 9, 1/4p. | Africa, Botswana | News item - production |
DM201511-2178 2015 | Rough-Polished | Diamcor Q2 diamond sales up. | rough-polished.com, Oct. 9, 1/4p. | Africa, South Africa | News item - Diamcor |
DM201511-2179 2015 | Rough-Polished | Alrosa received a high rating for corporate goverance practice. | rough-polished.com, Oct. 12, 1/4p. | Russia | News item - Alrosa |
DM201511-2180 2015 | Rough-Polished | Endiama boss blames soft market on "poor" marketing. | rough-polished.com, Oct. 12, 1/4p. | Africa, Angola | News item - Endiama |
DM201511-2181 2015 | Rough-Polished | Synthetic stones will not be considered precious stones in Russia - Moiseev. | rough-polished.com, Oct. 15, 1/4p. | Russia | News item - synthetics |
DM201511-2182 2015 | Rough-Polished | Zimbabwe seeks partners to explore over 100 kimberlites across the country. | rough-polished.com, Oct. 15, 1/4p. | Africa, Zimbabwe | News item - legal |
DM201511-2183 2015 | Rough-Polished | Zim diamond output continues to plummet. | rough-polished.com, Oct. 15, 1/4p. | Africa, Zimbabwe | News item - economics |
DM201511-2184 2015 | Rough-Polished | Lucapa pockets over $ A 5 million from latest Lulo diamonds sale. | rough-polished.com, Oct. 14, 1/4p. | Africa, Angola | News item - Lucapa |
DM201511-2185 2015 | Rough-Polished | Zim mines minister: not" so sure we have a diamond sector' anymore. | rough-polished.com, Oct. 16, 1/4p. | Africa, Zimbabwe | News item - Marange |
DM201511-2186 2015 | Rough-Polished | Forced consolidation of Zim diamond mining firms: we are shooting ourselves in the foot, says lawyer. | rough-polished.com, Oct. 16, 1/4p. | Africa, Zimbabwe | News item - legal |
DM201511-2187 2015 | Rough-Polished | Board appointments taking place at Diamond Producers association. | rough-polished.com, Oct. 19, 1/4p. | Global | News item - DPA |
DM201511-2188 2015 | Rough-Polished | De Beers sightholders defer 50pc of allocated goods at October sight. | rough-polished.com, Oct. 19, 1/4p. | Global | News item - De Beers |
DM201511-2189 2015 | Rough-Polished | Rio Tinto Diamonds puts production on hold at Argyle; reduces production forecast for Q4. | rough-polished.com, Oct. 19, 1/4p. | Australia | News item - Rio Tinto |
DM201511-2190 2015 | Rough-Polished | We should look at the chain of warranty as a solid ally of the Kimberley Process - S. Fischler | rough-polished.com, Oct. 19, 1p. | Global | News item - KP |
DM201511-2191 2015 | Rough-Polished | Alrosa produced 29.6 million carats of diamonds driving sales to $ 2.7 billion in the first nine months of 2015. | rough-polished.com, Oct. 21, 1/4p. | Russia | News item - Alrosa |
DM201511-2192 2015 | Rough-Polished | Rockwell Diamonds Q2 revenue up 32%. | rough-polished.com, Oct. 21, 1/4p. | Africa, South Africa | News item - Rockwell |
DM201511-2193 2015 | Rough-Polished | Lucara gets nod to extract samples from BK02 kimberlite. | rough-polished.com, Oct. 21, 1/4p. | Africa, Botswana | News item - Lucara |
DM201511-2194 2015 | Rough-Polished | Kennady completes Kelvin diamond valuation. | rough-polished.com, Oct. 21, 1/4p. | Canada, Northwest Territories | News item - Kennady |
DM201511-2195 2015 | Rough-Polished | Zim needs $ 4 billion by 2020 to finance mining activities. | rough-polished.com, Oct. 20, 1/4p. | Africa, Zimbabwe | News item - economics |
DM201511-2196 2015 | Rough-Polished | De Beers Q3 diamond output drops 27% to 6 m ct as weak market conditions persist. | rough-polished.com, Oct. 22, 1/4p. | Global | News item - De Beers |
DM201511-2197 2015 | Rough-Polished | Lucapa finds 14 more "special" diamonds at Lulo. | rough-polished.com, Oct. 22, 1/4p. | Africa, Angola | News item - Lucapa |
DM201511-2198 2015 | Rough-Polished | Zim's Murowa diamonds mothballed. | rough-polished.com, Oct. 22, 1/4p. | Africa, Zimbabwe | News item - Marange |
DM201511-2199 2015 | Rough-Polished | Laboratory grown diamonds are now a fact of life for the industry. T. Moses ( GIA) | rough-polished.com, Oct. 23, 1/4p. | Technology | News item - synthetics |
DM201512-2271 2015 | Rough-Polished | Lucapa awarded prospecting licence in Botswana's Orapa area. | rough-polished.com, Oct. 27, 1/4p. | Africa, Botswana | News item - Lucapa |
DM201512-2272 2015 | Rough-Polished | Zim mines minister Chidhakwa pressed to explain use of diamond revenue. | rough-polished.com, Oct. 27, 1/4p. | Africa, Zimbabwe | News item - legal |
DM201512-2273 2015 | Rough-Polished | Petra Q1 output up marginally. | rough-polished.com, Oct 29, 1/4p. | Africa, South Africa | News item - Petra |
DM201512-2274 2015 | Rough-Polished | Alrosa's net profit on RAS dropped 16% to 19.9 bn rubles in Jan-Sep. | rough-polished.com, Oct. 28, 1/4p. | Russia | News item - Alrosa |
DM201512-2275 2015 | Rough-Polished | Shore Gold released an updated diamond valuation results from Star-Orion South mine. | rough-polished.com, Oct. 28, 1/4p. | Canada, Saskatchewan | News item - Shore Gold |
DM201512-2276 2015 | Rough-Polished | De Beers says regional synergy on diamond beneficiation good for SA. | rough-polished.com, Oct. 30, 1/4p. | Africa, South Africa | News item - De Beers |
DM201512-2277 2015 | Rough-Polished | Zim ups levy for miners to fund exploration activity. | rough-polished.com, Oct. 30, 1/4p. | Africa, Zimbabwe | News item - legal |
DM201512-2278 2015 | Rough-Polished | SA diamond manufacturers told to turn "viscious circle of destruction" into virtuous circle of innovation". | rough-polished.com, Oct. 30, 1/4p. | Africa, South Africa | News item - beneficiation |
DM201512-2279 2015 | Rough-Polished | Kennady Diamonds announces updates Kennady North drilling. | rough-polished.com, Nov. 3, 1/4p. | Canada, Northwest Territories | News item - Kennady |
DM201512-2280 2015 | Rough-Polished | Up to 3 billion carats of synthetic diamonds nourish jewelery market - media. | rough-polished.com, Nov. 3, 1/4p. | Global | News item - synthetics |
DM201512-2281 2015 | Rough-Polished | Stellar Diamonds gets $ 2.65 m working capital. Tongo and Baoule | rough-polished.com, Nov. 3, 1/4p. | Africa, Sierra Leone | News item - Stellar |
DM201512-2282 2015 | Rough-Polished | Polished diamond prices soften in October. | rough-polished.com, Nov. 6, 1/4p. | Global | News item - prices |
DM201512-2283 2015 | Rough-Polished | Botswana rough diamonds exports continues to fall. | rough-polished.com, Nov. 6, 1/4p. | Africa, Botswana | News item - exports |
DM201512-2284 2015 | Rough-Polished | Zim diamond mining firms told to pay up or risk losing shares in new consolidated firm. ZCDC | rough-polished.com, Nov. 6, 1/4p. | Africa, Zimbabwe | News item - ZCDC |
DM201512-2285 2015 | Rough-Polished | Gokhran sold $ 1.16 m worth of diamonds at its last tender of the year. | rough-polished.com, Nov. 5, 1/4p. | Russia | News item - Gokhran |
DM201512-2286 2015 | Rough-Polished | Diamond Corp sees production ramp up at Lace year end, raises cash flow challenges. | rough-polished.com, Nov. 5, 1/4p. | Africa, South Africa | News item - DiamondCorp |
DM201512-2287 2015 | Rough-Polished | Zim mines minister says Marange licences expired. | rough-polished.com, Nov. 5, 1/4p. | Africa, Zimbabwe | News item - Marange |
DM201512-2288 2015 | Rough-Polished | Diamond exploration projects benefiting Angolans - mines minister. | rough-polished.com, Nov. 5, 1/4p. | Africa, Angola | News item - legal |
DM201512-2289 2015 | Rough-Polished | Russian government distinguished the work of scientists and engineers in diamond mining. ( permafrost) | rough-polished.com, Nov. 9, 1/4p. | Russia, Yakutia | News item - mining |
DM201512-2290 2015 | Rough-Polished | Angola rakes in about $ 100 m from Sept. diamond sales. | rough-polished.com, Nov. 9, 1/4p. | Africa, Angola | News item - economics |
DM201512-2291 2015 | Rough-Polished | Lucara Diamond 3 Q revenues top $ 91 million. | rough-polished.com, Nov. 10, 1/4p. | Africa, Botswana | News item - Lucara |
DM201512-2292 2015 | Rough-Polished | Stellar says Ebola-free Sierra Leone to benefit from its diamond deposits. | rough-polished.com, Nov. 10, 1/4p. | Africa, Sierra Leone | News item - Stellar |
DM201512-2293 2015 | Rough-Polished | Rio Tinto's Argyle pink diamonds tender delivers spectacular results. | rough-polished.com, Nov. 11, 1/4p. | Australia | News item - Rio Tinto |
DM201512-2294 2015 | Rough-Polished | Gem Diamonds revises 2015 production guidance for Letseng. | rough-polished.com, Nov. 13, 1/4p. | Africa, Lesotho | News item - Gem Diamonds |
DM201512-2295 2015 | Rough-Polished | Lisbon: a new diamond exchange in the offing. ( private with private investors) | rough-polished.com, Nov. 13, 1/4p. | Europe, Spain | News item - diamond exchange |
DM201512-2296 2015 | Rough-Polished | The downturn should stop by the middle of next year. Kristall | rough-polished.com, Nov. 17, 1/4p. | Russia | News item - Kristall |
DM201512-2297 2015 | Rough-Polished | Lucapa rakes in A$2.1 m from latest Lulo diamond sale. | rough-polished.com, Nov. 17, 1/4p. | Africa, Angola | News item - Lucapa |
DM201512-2298 2015 | Rough-Polished | Stellar secures loan to resume trial mining at Baoule, apply for Tongo mining licence. | rough-polished.com, Nov. 17, 1/4p. | Africa, Sierra Leone | News item - Stellar |
DM201512-2299 2015 | Rough-Polished | Diamond Corp commissions conveyor belt at Lace mine. | rough-polished.com, Nov. 16, 1/4p. | Africa, South Africa | News item - DiamondCorp |
DM201512-2300 2015 | Rough-Polished | Paragon provisionally suspends shares over funding uncertainty. | rough-polished.com, Nov. 18, 1/4p. | Africa, Lesotho | News item - Paragon |
DM201512-2301 2015 | Rough-Polished | Alrosa to update its consolidated budget for 2015. | rough-polished.com, Nov. 17, 1/4p. | Russia | News item - Alrosa |
DM201512-2302 2015 | Rough-Polished | Lucara finds 1,111 cart diamond in Botswana. | rough-polished.com, Nov. 19, 1/4p. | Africa, Botswana | News item - Lucara |
DM201512-2303 2015 | Rough-Polished | Lucara pockets $ 30 million from second exceptional stone tender. | rough-polished.com, Nov. 18, 1/4p. | Africa, Botswana | News item - Lucara |
DM201512-2304 2015 | Rough-Polished | Lucara recovers two more large white stones in Botswana. 813 and 374 Karowe | rough-polished.com, Nov. 20, 1/4p. | Africa, Botswana | News item - Lucara |
DM201512-2305 2015 | Rough-Polished | Dominion Diamond sales drop 35% in Q3 2016. | rough-polished.com, Nov. 23, 1/4p. | Canada, Northwest Territories | News item - Dominion |
DM201512-2306 2015 | Rough-Polished | Peregrine Diamonds announces $ 7 m rights issue to fund mining projects. | rough-polished.com, Nov. 23, 1/4p. | Canada, Nunavut, Baffin Island | News item - Peregrine |
DM201512-2307 2015 | Rough-Polished | DPA's marketing iniative excites Indian diamond industry. | rough-polished.com, Nov. 24, 1/4p. | India | News item - DPA |
DM201512-2308 2015 | Rough-Polished | Botswana Diamonds loss narrows during last fiscal year. | rough-polished.com, Nov. 24, 1/4p. | Africa, Botswana | News item - Botswana Diamonds |
DM201512-2309 2015 | Rough-Polished | Lucapa readies for next phase of Lulo exploration work. | rough-polished.com, Nov. 24, 1/4p. | Africa, Angola | News item - Lucapa |
DM201512-2310 2015 | Rough-Polished | Alrosa reports Q3 and 9m IFRS results. | rough-polished.com, Nov. 25, 1/4p. | Russia | News item - Alrosa |
DM201512-2311 2015 | Rough-Polished | Only 4 of 13 diamond cutting, polishing factories in Namibia operational - minister. | rough-polished.com, Nov. 25, 1/4p. | Africa, Namibia | News item - diamond cutting |
DM201512-2312 2015 | Rough-Polished | Stellar Diamonds narrows FY losses to Lbs 3.05 m. Baoule | rough-polished.com, Nov. 26, 1/4p. | Africa, Guinea | News item - Stellar |
DM201512-2313 2015 | Rough-Polished | Botswana diamond cutting, polishing sector to have more work hours, days. | rough-polished.com, Nov. 26, 1/4p. | Africa, Botswana | News item - cutting, polishing |
DM201512-2314 2015 | Rough-Polished | Diamond beneficiation remains Namibia's top priority. | rough-polished.com, Nov. 26, 1/4p. | Africa, Namibia | News item - beneficiation |
DM201512-2315 2015 | Rough-Polished | HSBC says Anglo could rake in $ 10 b from De Beers IPO. | rough-polished.com, Nov. 27, 1/4p. | Global | News item - De Beers |
DM201512-2316 2015 | Rough-Polished | Supply more rough diamond to factories, WFDB urges southern Africa. | rough-polished.com, Nov. 27, 1/4p. | Africa, South Africa | News item - WFDB |
DS201511-1873 2013 | Ruiz Cruz, M.D. | Are nanotubes and carbon nanostructures the precursors of coexisting graphite and microdiamonds in UHP rocks. | Diamond and Related Materials, Vol. 40, pp. 24-31. | Technology | Microdiamonds - responses |
| Abstract: A transmission electron microscopy study of garnet from diamond-grade gneisses of the Betic Cordillera (Spain) has revealed the presence of abundant, previously unrecognized, nanosized carbonaceous grains, coexisting with micrometer-sized graphite and diamond. The nanosized particles occur as multiwall nanotubes, and as polyhedral and quasi-spherical graphite + diamond nanoparticles, whereas larger graphite particles appear as rods and as tabular crystals. The topotactic relationships between graphite in nanoparticles and in micrometer-sized particles and the host garnet suggest that carbon nano- and microparticles precipitated from an originally homogeneous solid solution of carbon in the garnet. Based on orientation relationships and on experimental data it is suggested that the three main types of nanosized particles (nanospheres, polyhedral particles and nanotubes) were the precursor of the three main types of larger carbon phases (diamond, tabular and rod-shaped graphite particles, respectively). It is interpreted, as in the case of diamond-graphite nanocomposites, that diamond formation in the core of the nanoparticles is due to an increase of the cross-links between the layers, and then, to the collapse, at a certain point, of the whole graphite structure into diamond. This finding opens a new door for explaining the origin of some metamorphic diamonds and of coexisting graphite and diamond in ultrahigh pressure rocks. |
DS201512-1962 2015 | Rukhov, A.S., Bell, K., Amelin, Y. | Carbonatites, isotopes and evolution of continental mantle: an overview. | Symposium on critical and strategic materials, British Columbia Geological Survey Paper 2015-3, held Nov. 13-14, pp. 39-64. | Mantle | Carbonatite |
DS201510-1800 2014 | Ryabchikov, I.D., Kaminsky, F.V. | The composition of the lower mantle: source of diamonds with high-pressure mineral inclusions. | Deep-seated magmatism, its sources and plumes, Proceedings of XIII International Workshop held 2014., Vol. 2014, pp. 32-38. | Mantle | Experimental petrology - ferropericlase |
DS201502-0094 2015 | Ryabov, V. | The Early Triassic dyke belt in northern margin of Siberian platform. | Economic Geology Research Institute 2015, Vol. 17,, # 2215, 1p. Abstract | Russia | Minette, alnoite |
DS201509-0425 2015 | 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, Namibia | Plume, 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). |
DS201510-1801 2014 | Sablukov, S.M., Sablukova, L.I., Stegnitskiy, Yu.B., Karpenko, M.A. | Origin of the mantle xenoliths with green garnets from kimberlites ( Dike Newlands, southern Africa and Nyurbinskaya pipe, Yakutia). | Deep-seated magmatism, its sources and plumes, Proceedings of XIII International Workshop held 2014., Vol. 2014, pp. 178-202. | Africa, South Africa, Russia, Yakutia | Deposit - Dike Newlands, Nyurbinskaya |
| Abstract: Green garnets occur in concentrates of diamondiferous kimberlite bodies in Yakutia (Udachnaya, Mir, etc.), South Africa (Newlands, Bellsbank), Venezuela (Guaniamo sills), and Canada (Mud Lake field). Mantle xenoliths of rocks containing such garnets are very rare. We found peridotite xenoliths with green garnet in situ in kimberlites of the Newlands dike. Xenoliths are irregular in form, 4.5*1.9 cm, 1.5*0.8 cm, and 1.0*0.5 cm in size, and have similar modal compositions: gar(70)+ol(28)+sp(2), gar(9)+ol(90)+sp(1) and gar(50)+ol(30)+sp(20). Rock texture is medium-crystalline, while structure is massive. We also identified a garnet macrocryst of 0.5*0.4 cm in size with a pale green kelyphytic rim. Garnet composition in the studied samples is quite constant and is characterized by the high Cr2O3 content (10.94-11.99%) and CaO content (19.52-24.94%) at the reduced contents of TiO2 (0.24-0.52%). The chrome spinel is high Cr2O3 (55%) content and the low TiO2 (0.5-0.6%) content. Olivine is high-Mg (Fo95), but elevated CaO content (0.09%). Isotopic composition of oxygen in garnet (?18O = 4.05-4.25 pm) and olivine (?18O = 4.91 pm) differs drastically from the mantle values. Rb-Sr and Sm-Nd isotopic composition show the relatively "young" model age of the sample relative to the depleted mantle (1.78 billion years), the age of formation of this rocks is also relatively "young" - probable mezoproterozoic. In kimberlites and placers of the Nyurbinskaya pipe (Nakyn field, Yakutia) there are 4 green garnet grains of 0.5-2.0 mm in size, including one intergrowth gar+sp. Most garnets are characterized by the higher CaO (18.06-22.87%) and TiO2 (1.46, 1.65, 1.75%) contents not noted before for similar garnets. Studied green garnets have the similar "sine wave" type of REE distribution for low-Ti garnets and a "raised" type of REE distribution with enrichment in medium and light REE for high-Ti garnet.
All green garnets are characterized by an increased content of light REE and Sc. High-Ti garnets are characterized by an increased content of light and middle REE, as well as titanium, and a particularly sharply increased content of Zr (!). Paragenesis ol+sp is formed at 805oand 23.4 kbar, and paragenesis ol+gar is formed at 1080oand 23.8 kbar. The rocks are characterized by nonequilibrium paragenesis ol+sp+gar and formation at moderate depths (80-90 km) under conditions of high heat flow (52-55 mW/m2). Judging from modal composition of studied xenoliths (absence of clinopyroxene), variations in chemical compositions and trace element compositions, relatively "young" model age and non-mantle isotopy of oxygen in garnets, these rocks are not "wehrlites" and likely represent metasomatic rocks such as uvarovite-chromite veins or schlierens at the moderate depths of upper mantle - it is similar to uvarovite-chromite veins of the metasomatic or a hydrothermal origin in the crustal serpentinites. |
DS201511-1874 2015 | Saha, A., Manikyamba, C., Santosh, M., Ganguly, S., Khelen, A.C. | Platinum Group Elements ( PGE) geochemistry of komatiites and boninites from Dharwar Craton, India: implications for mantle melting processes. | Journal of Asian Earth Sciences, Vol. 105, pp. 300-319. | India | Boninites |
| Abstract: High MgO volcanic rocks having elevated concentrations of Ni and Cr are potential hosts for platinum group elements (PGE) owing to their primitive mantle origin and eruption at high temperatures. Though their higher PGE abundance is economically significant in mineral exploration studies, their lower concentrations are also valuable geochemical tools to evaluate petrogenetic processes. In this paper an attempt has been made to evaluate the PGE geochemistry of high MgO volcanic rocks from two greenstone belts of western and eastern Dharwar Craton and to discuss different mantle processes operative at diverse geodynamic settings during the Neoarchean time. The Bababudan greenstone belt of western and Gadwal greenstone belt of eastern Dharwar Cratons are dominantly composed of high MgO volcanic rocks which, based on distinct geochemical characteristics, have been identified as komatiites and boninites respectively. The Bababudan komatiites are essentially composed of olivine and clinopyroxene with rare plagioclase tending towards komatiitic basalts. The Gadwal boninites contain clinopyroxene, recrystallized hornblende with minor orthopyroxene, plagioclase and sulphide minerals. The Bababudan komatiites are Al-undepleted type (Al2O3/TiO2 = 23-59) with distinctly high MgO (27.4-35.8 wt.%), Ni (509-1066 ppm) and Cr (136-3036 ppm) contents. These rocks have low ?PGE (9-42 ppb) contents with 0.2-2.4 ppb Iridium (Ir), 0.2-1.4 ppb Osmium (Os) and 0.4-4.4 ppb Ruthenium (Ru) among Iridium group PGE (IPGE); and 1.4-16.2 ppb Platinum (Pt), 2.8-19 ppb Palladium (Pd) and 0.2-9.8 ppb Rhodium (Rh) among Platinum group PGE (PPGE). The Gadwal boninites are high-Ca boninites with CaO/Al2O3 ratios varying between 0.8 and 1.0, with 12-24 wt.% MgO, 821-1168 ppm Ni and 2307-2765 ppm Cr. They show higher concentration of total PGE (82-207 ppb) with Pt concentration ranging from 13 to 19 ppb, Pd between 65 and 180 ppb and Rh in the range of 1.4-3 ppb compared to the Bababudan komatiites. Ir, Os and Ru concentrations range from 0.6 to 2.2 ppb, 0.2 to 0.6 ppb and 1.4 to 2.6 ppb respectively in IPGE. The PGE abundances in Bababudan komatiites were controlled by olivine fractionation whereas that in Gadwal boninites were influenced by fractionation of chromite and sulphides. The Al-undepleted Bababudan komatiites are characterized by low CaO/Al2O3, (Gd/Yb)N, (La/Yb)N, with positive Zr, Hf, Ti anomalies and high Cu/Pd, Pd/Ir ratios at low Pd concentrations suggesting the derivation of parent magma by high degrees (>30%) partial melting of mantle under anhydrous conditions at shallow depth with garnet as a residual phase in the mantle restite. The komatiites are geochemically analogous to Al-undepleted Munro type komatiites and their PGE compositions are consistent with Alexo and Gorgona komatiites. The S-undersaturated character of Bababudan komatiites is attributed to decompression and assimilation of lower crustal materials during magma ascent and emplacement. In contrast, the higher Al2O3/TiO2, lower (Gd/Yb)N, for Gadwal boninites in combination with negative Nb, Zr, Hf, Ti anomalies and lower Cu/Pd at relatively higher Pd/Ir and Pd concentrations reflect high degree melting of refractory mantle wedge under hydrous conditions in an intraoceanic subduction zone setting. Higher Pd/Ir ratios and S-undersaturation of these boninites conform to influx of fluids derived by dehydration of subducted slab resulting into high fluid pressure and metasomatism of mantle wedge. |
DS201511-1875 2015 | Saha, L., Frei, D., Gerdes, A., Pat, J.K., Sarkar, S., Patole, V., Bhandari, A., Nasipuri, P. | Crustal geodynamics from the Archean Bundelk hand craton, India: constraints from zircon U-Pb-Hf isotope studies. | Geological Magazine, Rapid communication Oct. 14p. | India | Tectonics, geochronology |
| Abstract: A comprehensive study based on U-Pb and Hf isotope analyses of zircons from gneisses has been conducted along the western part (Babina area) of the E–W-trending Bundelkhand Tectonic Zone in the central part of the Archaean Bundelkhand Craton. 207Pb-206Pb zircon ages and Hf isotopic data indicate the existence of a felsic crust at ~ 3.59 Ga, followed by a second tectonothermal event at ~ 3.44 Ga, leading to calc-alkaline magmatism and subsequent crustal growth. The study hence suggests that crust formation in the Bundelkhand Craton occurred in a similar time-frame to that recorded from the Singhbhum and Bastar cratons of the North Indian Shield. |
DS201501-0028 2014 | Salomon, E., Koehn, D., Passchier, C. | Brittle reactivation of ductile shear zones in NW Namibia in relation to South Atlantic rifting. | Tectonics, Vol. 34, pp. 70-85. | Africa, Namibia | Tectonics |
DS201511-1876 2015 | Salzmann, C.G., Murray, B.J., Shephard, J.J. | Extent of stacking disorder in diamond. ( hexagonal) | Diamond and Related Materials, Vol. 59, pp. 69-72. | Technology | Lonsdaleite |
| Abstract: Hexagonal diamond has been predicted computationally to display extraordinary physical properties including a hardness that exceeds cubic diamond. However, a recent electron microscopy study has shown that so-called hexagonal diamond samples are in fact not discrete materials but faulted and twinned cubic diamond. We now provide a quantitative analysis of cubic and hexagonal stacking in diamond samples by analysing X-ray diffraction data with the DIFFaX software package. The highest fractions of hexagonal stacking we find in materials which were previously referred to as hexagonal diamond are below 60%. The remainder of the stacking sequences are cubic. We show that the cubic and hexagonal sequences are interlaced in a complex way and that naturally occurring Lonsdaleite is not a simple phase mixture of cubic and hexagonal diamond. Instead, it is structurally best described as stacking disordered diamond. The future experimental challenge will be to prepare diamond samples beyond 60% hexagonality and towards the so far elusive 'perfect' hexagonal diamond. |
DC201502-1684 2015 | Sanatana Diamonds Inc. | Shareholders update : Green Lake prospect. | Sanatana Resources, Jan. 23, 1/4p. | Canada, Saskatchewan | News item - press release |
DS201512-1963 2015 | Sappin, A-A., Beaudoin, G. | Rare earth elements in Quebec, Canada: main deposit types and their economic potential. | Symposium on critical and strategic materials, British Columbia Geological Survey Paper 2015-3, held Nov. 13-14, pp. 265- | Canada, Quebec | Rare earths |
| Abstract: Rare earth elements (REE) are strategic metals vital to global economic growth because they are used in a wide range of high-technology industries (e.g., energy, transport, and telecommunications; Walters et al., 2011). The world production and reserves are mainly owned by China. In 2008, the Chinese government introduced export quotas on rare metals, which led to a global search for new sources of REE. Québec has substantial REE resources (Simandl et al., 2012), which may contribute to future production. Gosselin et al. (2003) and Boily and Gosselin (2004) inventoried rare metals (REE, Zr, Nb, Ta, Be, and Li) occurrences and deposits in Québec and, based mainly on lithological association, subdivided them into seven types: 1) deposits associated with peraluminous granitic complexes; 2) deposits associated with carbonatite complexes; 3) deposits associated with peralkaline complexes; 4) deposits associated with placers and paleoplacers; 5) iron oxide, Cu, REE, and U deposits; 6) deposits associated with granitic pegmatites, migmatites, and peraluminous to metaluminous granites; and 7) deposits associated with calc-silicate and metasomatized rocks or skarns. Herein we review REE mineralization in the province, adopting a more genetic scheme based on the classifi cation of Walters et al. (2011). The REE occurrences and deposits are subdivided into primary deposits, formed by magmatic and/ or hydrothermal processes, and secondary deposits, formed by sedimentary processes and leaching. Primary deposits are then subdivided into four types: 1) carbonatite complex-associated; 2) peralkaline igneous rock-associated; 3) REE-bearing Iron- Oxide-Copper-Gold (IOCG) deposits; and 4) hyperaluminous/ metaluminous granitic pegmatite-, granite-, and migmatiteassociated deposits, and skarns. Secondary deposits are subdivided into two deposit types: 1) placers and paleoplacers and 2) REE-bearing ion-adsorption clays. |
DS201509-0426 2015 | Saraiva dos Santos, T.J., Da Silva Amaral, W., Ancelmi, M.F., Pitarello, M.Z., Fuck, R.A., Dantas, E.L. | U-Pb age of coesite bearing eclogite from NW Borborema Province, NE Brazil: implications for western Gondwana assembly. | Gondwana Research, Vol. 28, pp. 1183-1196. | South America, Brazil | UHP |
| Abstract: The Late Neoproterozoic assembly of western Gondwana played an important role in the subduction of oceanic and continental lithospheres. Such event was also a source of arc magmatism, reworking of cratonic margins and development of ultra-high pressure (UHP) suture zones. In the Borborema province, NE Brazil, we have described for the first time UHP rocks enclosed within gneiss migmatite and calc-silicate rocks. They bear coesite included in atoll-type garnet from metamafic rocks, identified by petrographic study and Raman microspectroscopy analysis. U-Pb zircon dating of the leucosome of the migmatites and the calc-silicate rock displays, concordant ages of 639 ± 10 Ma and 649.7 ± 5 Ma, respectively, here interpreted as the minimum age of the eclogitization event in the region. U-Pb zircon dating of the coesite-bearing rock defined a concordia age of 614. 9 ± 7.9 Ma that comprised the retrograde eclogitic conditions to amphibolite facies. The UHP rocks, mostly retrograded to garnet amphibolites, occur enclosed in the Paleoproterozoic continental block composed of calc-silicate rocks, migmatized sillimanite gneiss, mylonitic augen gneiss and granitic and tonalitic gneiss along a narrow N-S oriented belt between the Santa Quitéria magmatic arc and the Transbrasiliano lineament. This block was involved in the subduction to UHP eclogite depths, and was retrogressed to amphibolite during its exhumation and thrusting. Our data indicate an important Neoproterozoic transcontinental suture zone connecting the Pharusian belt with Borborema Province, and probably with the Brasília belt in central Brazil. |
DS201504-0215 2015 | Sarkar, C., Heaman, L.M., Pearson, D.G. | Duration and periodicity of kimberlite volcanic activity in the Lac de Gras kimberlite field, Canada and some recommendations for kimberlite geochronology. | Lithos, Vol. 218-219, pp. 155-166. | Canada, Northwest Territories | Deposit - Eddie |
DM201504-1335 2015 | Saskatchewan Geological Survey | Diamond activity Fort a la Corne, Pikoo area. | Saskatchewan Exploration and Development Highlights 2014, p. 10. | Canada, Saskatchewan | News item - Pikoo |
DS201501-0029 2014 | Saskatchewan Mining Association | Where do diamonds come from and how can we find them? Overview of companies working in Saskatchewan ( Shore Gold, North Arrow, Stornoway) | Saskatchewan Mining Association, Fall,Winter p. 5,6. | Canada, Saskatchewan | Brief overview |
DS201511-1877 2015 | Sastry, M.D., Mane, S., Gaonkar, M., Bhide, M.K., Desai, S.N., Ramachandran, K.T. | Luminescence studies of gemstones and diamonds. | International Journal of Luminescence and Applications, Vol. 5, 3, pp. 293-297. | Technology | Luminescence |
| Abstract: Some of the minerals like Corundum, chryso beryl, beryllium alumino silicate (emerald) and also Diamond exhibit exceptional optical properties[1] and in some cases attractive colours; in India these were recognized quite early since the days of Indus valley civilization. In more recent times there has been a lot of scientific interest in colours and colour modifications in Gem minerals and in Diamonds. Science of gem stones deals with their identification by non destructive means and understanding of origin of colour and excellent optical properties[1]. Optical methods have long been used to obtain properties like ‘Refractive Index’ which still remains an important parameter as a preliminary test to identify the gemstone/mineral. The spectroscopic studies of gem grade minerals are essentially directed towards some of these features in identifying and understanding the spectral properties of chromophores, either chemical impurities and/or radiation induced point defects, in solids. In this context a variety of spectroscopic methods are used to address the problems of the Gem stone identification and identification of origin of colours and colour modification treatments. The methods frequently used in Gem testing labs are the following: (i)Electronic absorption in UV-Visible-NIR range.(ii)UV-Vis excited luminescence, (iii) Vibrational spectra – Absorption in the Infra red range (iv) Vibrational spectra using Light Scattering (Raman spectroscopy) (v)Surface Fluorescence mapping Under deep UV excitation. The present paper deals with the luminescence studies in rubies, sapphires, emeralds and diamonds. Special mention may be made of fluorescence mapping using deep UV excitation (around 205 nm) corresponding to the band gap of diamond. Under such an excitation inter band excitation takes place creating a e-h pair and most of the absorption and subsequent emission being restricted to the surface. This makes surface mapping possible and thereby elucidating the growth patterns. This is invaluable in the diagnostics for the detection of synthetic diamonds. In this introductory presentation on the Luminescence methods in Gemmology, we give a brief account of optical spectroscopic methods which mainly deal with identification of corundum based gem stones (rubies, sapphire) and diamonds including the electronic absorption and luminescence of chromophore centres. In gem testing infrared absorption and Raman scattering methods are main work horses and they will be brought in as and when necessary to give a complete picture. |
DS201508-0375 2015 | Sautter, V. | Martian crustal rocks bear a strong resemblance to tonalite-trondjemite-granodiorites… Earth's continental crust ( 2.5 billion years ago). | Physics.org, July 14, 1/4p. | Mantle | Crust - history |
DS201502-0095 2014 | Saveleva, V.B., Bazarova, E.P., Danilov, B.S. | New finds of carbonatite like rocks in the western Baikal region. | Doklady Earth Sciences, Vol. 459, 2, pp. 1483-1487. | Russia | Carbonatite |
DS201512-1964 2015 | Saxon, M., Leijd, M., Forrester, K., Berg, J. | Geology, mineralogy, and metallurgical processing of the Norra Karr heavy REE deposit, Sweden. | Symposium on critical and strategic materials, British Columbia Geological Survey Paper 2015-3, held Nov. 13-14, pp. 97-108. | Europe, Sweden | Rare earths |
| Abstract: The Norra Kärr peralkaline complex is about 300 km southwest of Stockholm in southern Sweden (Fig. 1). As the only heavy REE deposit in the European Union, Norra Kärr is signifi cant for the security of future REE, zirconium (Zr) and hafnium (Hf) supply (European Commission’s European Rare Earths Competency Network; ERECON, 2015). The project is well serviced by power and other infrastructure that will allow year-round mining and processing. A four-lane highway links Scandinavia to mainland Europe and passes with 1km of Norra Kärr. The skill-rich cities of Linköping and Jönköping, lie within daily commuting distances from Norra Kärr. A rail line that passes within 30 km of the site may be used to transport feed stocks and products. If Norra Kärr is developed, European REE users will no longer require substantial material stockpiles to deal with market uncertainties. |
DS201507-0333 2015 | Sazonova, L.V., Nosova, A.A., Kargin, A.V., Borisovskiy, S.E., Tretyachenko, V.V., Abazova, Z.M., Griban, Yu.G. | Olivine from the Pionerskaya and V. Grib kimberlite pipes, Arkangelsk diamond province, Russia: types, composition, and origin. | Petrology, Vol. 23, 3, pp. 227-258. | Russia | Deposit - Grib |
DS201510-1802 2015 | Scheiber-Enslin, S.E., Ebbing, J., Webb, S.J. | New depth maps of the main Karoo basin, used to explore the Cape isostatic anomaly, South Africa. | South African Journal of Geology, Vol. 118, 3, pp. 225-248. | Africa, South Africa | Geophysics - seismics |
| Abstract: Here we present a comprehensive depth and thickness map of the main Karoo and Cape Basins using borehole and reflection seismic data. The depth to the Whitehill Formation, which is the focus of current shale gas interest within the Karoo, is also mapped. Change: The deepest part of the basin is in the south, along the northern boundary of the Cape Fold Belt (~4000 m in the southwest Karoo and ~5000 m in the southeast; ~5500 to 6000 m sediment thickness). The Whitehill Formation along this boundary reaches a depth of ~3000 m in the southwest and ~4000 m in the southeast. Limited borehole data in the southeastern Karoo show a broad deepening of the basin here compared to the southwestern Karoo. In the southeast near East London faulting has resulted in deepening of the basin close to the coast, with the Whitehill Formation deepening to over ~5000 km. Seismic and borehole data show that the Cape Supergroup pinches out below the Karoo Basin around Beaufort West and Graaff-Reinet in the southern Karoo (32.6°S for the Bokkeveld and 32.4°S for the Table Mountain Group). The Cape Supergroup reaches thicknesses of around 4 km in the south. The gravity effect of these sediments does not account for the Cape Isostatic Anomaly (CIA) in the southern part of the Karoo Basin near Willowmore and Steytlerville, i.e., an ~45 mGal Bouguer gravity low. A refraction seismic profile over the anomaly shows this region is associated with a large volume of low velocity/density shallow sediments (4.5 m/s2, 2500 kg/m3), as well as a low velocity/density anomaly associated with a normal fault and the Klein Winterhoek Thrust Fault (5.5 m/s2, 2650 kg/m3). These low density shallow sediments are explained by uplift of Karoo and Cape sediments of ~2 km or greater that is evident on Soekor reflection seismic data. This deformation has brought lower density shales (1800 to 2650 kg/m3) of the Ecca Group closer to the surface. These shallower features along with a deeper lower crust in this region (6.5 m/s2, 2900 kg/m3) are interpreted to account for the CIA. |
DS201502-0096 2014 | Schingaro, E., Kullerud, K., laclamita, M., Mesto, E., Scordari, F., Zozulya, D., Erambert, M., Ravna, E.J.K. | Yangzhumingite and phlogopite from the Kvaloya lamproite (North Norway): structure, composition and origin. | Lithos, Vol. 210-211, pp. 1-13. | Europe, Norway | Lamproite |
DS201511-1878 2015 | Schmadicke, E., Gose, J., Reinhardt, J., Will, T.M., Stalder, R. | Garnet in cratonic and non-cratonic mantle and lower crustal xenoliths from southern Africa: composition, water in corporation and geodynamic constraints. | Precambrian Research, Vol. 270, pp. 285-299. | Africa, South Africa, Lesotho, Namibia | Kaapvaal craton, Rehoboth Terrane |
| Abstract: Garnets from kimberlite-hosted mantle and a few xenoliths from the lower crust were investigated for water, major, minor, and trace elements. Xenoliths from the mantle comprise pyroxenite, eclogite, alkremite, and peridotite, and crustal xenoliths are mafic high-pressure granulites. Samples from South Africa, Lesotho, and Namibia comprise two principal settings, Kaapvaal Craton (‘on craton’) and Rehoboth terrane (‘off craton’). The composition of garnet depends on rock type but is unrelated to the setting, except for Ti and Cr. In garnets from ‘off craton’ mantle xenoliths, Ti positively correlates with Cr whereas those from ‘on craton’ samples reveal a negative correlation between both elements. Rare earth element patterns indicative of a metasomatic overprint are observed in garnets from both settings, especially in eclogitic garnet. Water contents in garnet are low and range from <1 to about 40 ppm. No setting-related difference occurs, but a weak correlation between water and rock type exists. Water contents in garnets from eclogite and mafic granulite are lower than those in pyroxenite, alkremite, and peridotite. All garnets are water under-saturated, i.e. they do not contain the maximum amount of water that can be accommodated in the mineral structure. Cratonic and non-cratonic samples also show the same characteristics in the infrared (IR) absorption spectra. An absorption band at 3650 cm-1 is typical for most mantle garnets. Bands at 3520 and 3570 cm-1 are present only in TiO2-rich garnets from the Rehoboth terrane and are ascribed to a Ti-related hydrogen substitution. A number of garnets, especially from the Kaapvaal Craton, contain molecular water in addition to structural water. Molecular water is inhomogeneously distributed at grain scale pointing to local interaction with fluid and to disequilibrium at grain scale. These garnets consistently reveal either submicroscopic hydrous phases or additional IR bands at 3630 and 3610-3600 cm-1 caused by structural water. Both features do not occur in garnets in which molecular water is absent. The observations imply (i) relatively late introduction of fluid, at least in cases where hydrous phases formed, and (ii) a relatively dry environment because only water-deficient garnets are able to incorporate additional structural water. Most importantly, they imply (iii) that the low water contents are primary and not due to water loss during upward transport. This late water influx is not responsible for the metasomatic overprint indicated by garnet REE patterns. The results of this study suggest dry conditions in the lithosphere, including mantle and crustal sections of both the Kaapvaal Craton (‘on craton’) and the Rehoboth terrane (‘off craton’). If the low water contents contributed to the stabilization of the Kaapvaal cratonic root (Peslier et al., 2010) the same should apply to the Rehoboth lithosphere where the same variety of rock types occurs. The extremely low water contents in eclogite relative to pyroxenite may be explained by an oceanic crust origin of the eclogites. Subduction and partial melting would cause depletion of water and incompatible elements. The pyroxenites formed by crystal accumulation in the mantle and did not suffer melt depletion. Such a difference in origin can be reconciled with the low Ti contents in eclogitic garnet and the high Ti contents in pyroxenitic garnet. |
DM201510-2060 2015 | Schmadicke, E., Will, T.M., Mezger, K. | A change of plans for Ekati. It’s a delay for Jas as Dominion beings the Sable kimberlite forward. | Resourceclips.com, Sept. 14, 1p. | Canada, Northwest Territories | News item - Dominion |
DS201511-1879 2015 | Schmadicke, E., Will, T.M., Mezger, K. | Garnet pyroxenite from the Shackleton Range, Antarctica: intrusion of plume-derived picritic melts in the continental lithosphere during Rodinia breakup. | Lithos, Vol. 238, pp. 185-206. | Antarctica | Picrite |
| Abstract: Lenses of ultramafic rocks occur in supracrustal high-grade gneiss in the northern Haskard Highlands, Shackleton Range, East Antarctica. Olivine-bearing garnet pyroxenite is the dominant rock type that is associated with hornblendite and subordinate spinel peridotite and amphibolite. The high-pressure (23-25 kbar) garnet-olivine assemblage of the pyroxenite formed during Pan-African eclogite-facies metamorphism. Associated collisional tectonics led to the incorporation of the ultramafic and mafic rocks in upper crustal rocks of a subducting continental margin. The ultramafic-mafic rocks are tracers of a palaeo-suture zone and are critical for reconstructing Gondwana amalgamation. Thus, it is important to infer the tectonic setting of the rocks prior to emplacement into their current position, i.e. were the rocks part of the oceanic crust, the sub-oceanic, or the sub-continental mantle? Major and trace elements together with Pb and Nd isotope data imply that the precursor rocks of the pyroxenites and hornblendites (the latter being retrogressed pyroxenite equivalents) formed as plume-related melts, with many characteristics typical for ocean-island tholeiitic magmas. Hence, pyroxenite and hornblendite are interpreted as metamorphic equivalents of picritic melts. They differ from most garnet pyroxenites worldwide in composition and genesis. The latter formed as high-pressure clinopyroxene-rich cumulates from basaltic melts. The volumetrically minor amphibolites, sharing many geochemical characteristics with pyroxenites and hornblendites, are also interpreted as metamorphic equivalents of plume-related melts. It is inferred that the picritic melts crystallized at medium- to high-pressure conditions in the upper continental mantle or in the transition zone between mantle and continental crust. The subordinate spinel peridotites are interpreted as fragments of the uppermost, depleted mantle. They are probably the wall rocks into which the picritic melts intruded. The Pb and Nd mantle separation ages of the picritic melts range from 770 to 870 Ma. These model ages are very similar to the emplacement ages of numerous global mafic and ultramafic dykes, which are genetically linked to mantle plume activity that initiated Rodinia rifting and breakup. The protoliths of pyroxenite and related rocks in the Shackleton Range most likely formed during the initial stages of plume magmatism that eventually led to Rodinia breakup. |
DS201501-0030 2014 | Schmidt, M.W., Gao, C., Golubkova, A., Rohrbach, A., Connolly, J.A.D. | Natural moissanite ( SiC) - a low temperature mineral formed from highly fractionated ultra-reducing COH-fluids. | Progress in Earth and Planetary Science, Vol. 1, pp. 27- | | Moissanite |
DS201512-1965 2015 | Schmidt, N., Kramers, P. | The Gahcho Kue mine dewatering experience, winter 2014-2015. | 43rd Annual Yellowknife Geoscience Forum Abstracts, abstract p. 93. | Canada, Northwest Territories | Deposit - Gahcho Kue |
| Abstract: Construction of the De Beers Gahcho Kué Mine required that a portion of Kennady Lake be dewatered to provide access to kimberlite pipes on the lakebed. The Construction Water Management Plan considered an initial dewatering volume of approximately 18.7 Mm3, to be discharged to two downstream waterbodies (Lake N11 and Kennady Lake Area 8). This dewatering was originally planned to occur during the open water season, after the spring freshet peak. The project received its Type A Water Licence from the Mackenzie Valley Land and Water Board on September 24, 2014, and before that date it had become apparent that winter dewatering would be required to prevent a significant delay in the project development. Potential adverse impacts related to winter dewatering were identified and were primarily related to aufeis development. Aufeis is defined as an ice deposit, formed by vertical growth of layers as thin flows of water are exposed to freezing temperatures. These may have adverse effects on erosion, fish and fish habitat. Action levels for winter dewatering were developed, based on site-specific hydrological characteristics, and were included in the Aquatic Effects Monitoring Program for the Mine. This allowed field measurements to be compared to action levels during the dewatering program. Field measurements included telemetry to monitor lake hydrostatic water surface elevations, as well as periodic visits to the receiving lake outlets and downstream areas to examine ice and flow conditions. Winter dewatering commenced on December 20, 2014, with pumping to Kennady Lake Area 8. Pumping was suspended on January 4, 2015, as the action level for that location was approached. Approximately 779,000 m3 of water was released over 16 days. Dewatering discharges were then pumped to Lake N11, with pumping commencing on February 1, 2015 and continuing through the winter period, as the action level for that location was not exceeded. Over the 103 day period through May 14, 2015, approximately 6,021,000 m3 of water was released. A total of 6,800,000 m3 of water was discharged from Kennady Lake over the winter dewatering period, or about 36% of the planned initial dewatering volume. Winter and subsequent open-water season reconnaissance did not identify any adverse effects due to winter dewatering. This presentation will discuss winter dewatering risks, action level development, field program observations, and factors contributing to the overall success of the program. |
DS201508-0376 2015 | 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 Plateau | Diatremes - Moses Rock, Mule's Ear, Garnet Ridge, Cane Valley, Red Mesa, Buell Park, Green Knobs |
DS201506-0294 2015 | Science Daily | Ascent or no ascent? How hot material is stopped in Earth's mantle. | Science Daily, 4p. | Mantle | Magmatism |
DS201512-1966 2015 | Science Daily | Life on Earth likely started 4.1 billion years ago, much earlier than scientists thought. | Science Daily, Oct. 19, 2p. | Australia | Zircon geochronology |
DC201506-1685 2015 | Scio Diamond Technology Corporation | Scio Diamond doubles diamond-growing capacity. | Scio Diamond Technology Corporation, Apr. 27, 1p. | Technology | News item - press release |
DC201507-1686 2015 | Scio Diamond Technology Corporation | Scio Diamond's lab grown fancy pink diamonds reach retail market USA. | Scio Diamond Technology Corporation, June 2, 1p. | United States | News item - press release |
DC201510-2365 2015 | SDKA International | Subsidiary SDKA Diamonds DMCC announces membership to the Dubai multi commodities centre and the Dubai diamond exchange. | SDKA International, Sept. 16, 1p. | Dubai | News item - press release |
DS201503-0173 2015 | Selway, K., Ford, H., Kelemen, P. | The seismic mid-lithosphere discontinuity. | Earth and Planetary Science Letters, Vol. 414, March 15, pp. 45-57. | Mantle | Geophysics - seismic |
DS201510-1803 2015 | Shapovalov, Yu.B., Gorbachev, N.S., Kostyuk, A.V., Sultanov, D.M. | Geochemical features of carbonatites of the Fennoscandian shield. | Doklady Earth Sciences, Vol. 463, 2, pp. 833-838. | Europe, Norway, Russia, Kola Peninsula, Karelia | Carbonatite |
| Abstract: The petrochemistry of carbonatites of three formation types were studied: (1) ultrahigh-pressure garnet-containing carbonatites (UHPC) of the Caledonian sheet (Tromsö, Norway); (2) rocks of the carbonatite-lkaline-ultrabasic Kovdor massif (the Kola Peninsula); and (3) rocks of the carbonatite-alkaline-gabbroid Tikshozero massif (north of Karelia). The samples of carbonatites were examined and tested with a microprobe; the microelements were determined using the ICP-MS technique at the Institute of Microelectronics Technology and High Purity Materials (Chernogolovka). The carbonatites of the Kovdor and Tikshozero massifs are characterized by similar negative REE trends, with a degree of REE enrichment of the Tikshozero carbonatites. The UHPC from Tromsö are different from those of the Kovdor and Tikshozero massifs in the negative trend along with lower concentrations of light REEs. The Tromsö UHPC are similar to the carbonatites of the Kovdor and Tikshozero massifs in the trend and concentrations of heavy REEs. The carbonatites of the Fennoscandian shield of various formation times and types are characterized by the geochemical similarity to those in different regions of the world with the sources associated to mantle plumes. This similarity might be caused by the formation of the mantle carbonated magmas of carbonatite-containing igneous complexes from a mantle source enriched under either mantle metasomatism or plume-lithosphere interaction, with similar mechanisms of formation. The appearance of the formations as such within a wide time interval points to the long-term occurrence of a superplume at the Fennoscandian shield and to permanent activation of the related processes of magma formation. |
DS201502-0097 2015 | Sharapov, V., Sorokin, K., Perepechko, Y. | Dynamics of mantle rock metasomatic transformation in permeable lithospheric zones beneath Siberian craton. | Economic Geology Research Institute 2015, Vol. 17,, # 2153, 1p. Abstract | Russia | Geothermometry |
DS201507-0334 2015 | Sharapov, V.N., Chudnenko, K.V., Tomilenko, A.A. | The physicochemical dynamics of carbonatization of the rocks of lithospheric mantle beneath the Siberian Platform. | Russian Geology and Geophysics, Vol. 56, pp. 696-708. | Russia | Carbonatite |
DS201502-0098 2015 | Sharkov, E. | Petrological processes in mantle plume heads: evidence from study of mantle xenoliths in the late Cenozoic alkali Fe-Ti basalts in western Syria. | Economic Geology Research Institute 2015, Vol. 17,, # 2144, 1p. Abstract | Africa, Syria | Magmatism |
DS201504-0216 2015 | Sharkov, E.V., Bogatikov, O.A. | Roots of magmatic systems in the large continental igneous Provinces. | Doklady Earth Sciences, Vol. 460, 2, pp. 154-158. | Europe, Syria | Mantle xenoliths |
DS201502-0099 2014 | Sharygin, I.S. | Accessory minerals from shared lherzolites in the Udachnaya-East kimberlitic pipe ( Yakutia): origin and petrogenetic meaning. IN RUSSIAN | Thesis, Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciemces, Novosibirsk, 248p. Available IN RUSSIAN | Russia | Deposit - Udachnaya-East |
DS201509-0427 2015 | Shatsky, V.S., Skuzovatov, S.Yu., Ragozin, A.L., Sobolev, N.V. | Mobility of elements in a continental subduction zone: evidence from the UHP metamorphic complex of the Kokchetav massif. | Russian Geology and Geophysics, Vol. 56, pp. 1016-1034. | Russia | Kokchetav massif |
| Abstract: We studied clastics of high-alumina garnet-kyanite-mica schists and garnet-kyanite-quartz granofelses, including diamond-bearing ones, found in the eluvial sediments near Lake Barchi. In contents of major elements the studied rocks correspond to argillaceous shales. The garnet-kyanite-quartz granofelses are poorer in K (0.49-1.35 wt.% K2O) than the garnet-kyanite-mica schists (4.9-2.2 wt.% K2O) but have the same contents of other major components. The REE patterns of most of the garnet-kyanite-phengite schists are similar to those of the Post-Archean Australian Shale (PAAS) (xLa/Yb = 13). All garnet-kyanite-quartz rocks are much stronger depleted in LREE (xLa/Yb = 1.4) and other incompatible elements. Our studies show that allanite and monazite are the main concentrators of LREE and Th in the garnet-kyanite-phengite rocks of the Barchi site. Monazite, occurring as inclusions in garnet, contains not only LREE but also Th, U, and Pb. Rutile of the nondepleted rocks is enriched in Fe and Nb impurities only. The garnet-kyanite-quartz granofelses bear rutile, apatite, and xenotime as accessory phases. Rutile of the depleted rocks shows wide variations in contents of Nb, Ta, and V impurities. In places, the contents of Nb and Ta reach 10.5 and 2.3 wt.%, respectively. The rutile decomposes into rutile with Nb (1.4 wt.%) and Fe (0.87 wt.%) impurities and titanium oxide rich in Fe (6.61 wt.%), Nb (up to 20.8 wt.%), and Ta (up to 2.81%) impurities. Based on the measured contents of incompatible elements in differently depleted high-alumina rocks, the following series of element mobility during UHP metamorphism has been established: Th > Ce > La > Pr > Nd > K > Ba > Rb > Cs > Sm > Eu. The contents of U, P, and Zr in the depleted rocks are similar to those in the nondepleted rocks. The studies have shown that metapelites subducted to the depths with diamond stability conditions can be depleted to different degrees. This might be either due to their exhumation from different depths of the subduction zone or to the presence of an external source of water controlling the temperature of dissolution of phengite and the formation of supercritical fluid/melt. |
DS201507-0335 2015 | Shatsky, V.S., Zedgenizov, D.A., Ragozin, A.L., Kalinina, V.V. | Diamondiferous subcontinental lithospheric mantle of the northeastern Siberian Craton: evidence from mineral inclusions in alluvial diamonds. Kapchan Fold Belt Olenek Province | Gondwana Research, Vol. 28, 1, pp. 106-120. | Russia | Diamond - inclusions |
DS201502-0100 2015 | Shchukina, E., Agashev, A., Pokhilenko, N. | Multistage metasomatism in lithospheric mantle beneath V. Grib pipe ( Arkhangelsk Diamondiferous province, Russia): evidence from REE patterns in garnet xenocrysts. | Economic Geology Research Institute 2015, Vol. 17,, # 1940, 1p. Abstract | Russia, Kola Peninsula, Archangel | Deposit - Grib |
DS201507-0336 2015 | Shchukina, E.V., Agashev, A.M., Golovin, N.N., Pokhilenko, N.P. | Equigranualr eclogites from the V. Grib kimberlite pipe: evidence for Paleoproterozoic subduction on the territory of the Arkangelsk Diamondiferous province. | Doklady Earth Sciences, Vol. 462, 1, pp. 497-501. | Russia, Archangel, Kola Peninsula | Deposit - Grib |
DS201502-0101 2015 | Shertl, H.P., Neuser, R.D., Logvinova, A.M., Wirth, R., Sobolev, N.V. | Cathodluminescence microscopy of the Kokchetav ultra high pressure calcsilicate rocks: what can we learn from silicates, carbon hosting minerals and diamond? | Russian Geology and Geophysics, Vol. 56, 1-2, pp. 100-112. | Russia, Kazakhstan | Kokchetav massif |
DS201506-0295 2015 | Shigley, J.E., Breeding, C.M. | Visible absorption spectra of colored diamonds. | Gems & Gemology, Vol. 51, 1, pp. 41-43. | Technology | Coloured diamonds |
DS201512-1967 2015 | Shives, R.B.K. | Using gamma ray spectrometry to find rare metals. | Symposium on critical and strategic materials, British Columbia Geological Survey Paper 2015-3, held Nov. 13-14, pp. 199-210. | Technology | Rare earths |
| Abstract: For decades, gamma ray spectrometry has been used worldwide to map rocks and locate mineralization in diverse geological settings (Shives et al., 1997). The method is particularly well suited to rare metal and REE (rare earth element) exploration because primary host rocks are enriched in incompatible elements known as LILE (large-ion lithophile elements K, Rb, Cs, Sr, Ba) and HSFE (high fi eld strength elements Zr, Nb, Hf, REEs, Th, U and Ta). As a result, the ores of REEs are commonly radioactive because host rocks, orebearing minerals, or associated accessory minerals may contain trace to anomalous concentrations of radioactive elements K, U and Th. These radioactive elements provide a useful and direct exploration vectors. Gamma ray data are often collected simultaneously with magnetic, electromagnetic, and gravity data in multisensor surveys. The objective of this extended abstract is to emphasize the importance of gamma ray spectrometry as a primary exploration tool for rare metal deposits. Case histories presented herein illustrate radioactive element and magnetic signatures associated with diverse rare metal deposit types in different geological settings. Canadian examples include: Cantley, Quebec (Quinnville and Templeton carbonatites); Oka, Quebec (carbonatite); Bancroft, Ontario (pegmatites); Allan Lake, Ontario (a blind carbonatite discovery); Nechalacho, Northwest Territories (previously called Thor Lake; altered ultra-alkaline layered complex); Strange Lake, Quebec (peralkaline granite, pegmatite); and one each from British Columbia and Labrador. Also presented are examples from Greenland, Norway, and Mozambique. |
DS201503-0174 2015 | Shor, R. | Rough diamond auctions: sweeping changes in pricing and distribution. | Gems & Gemology, Vol. 50, 4, winter 2014, 18p. | Global | Diamond production |
DS201512-1968 2015 | 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 Terae | Gems & Gemology, Vol. 51, 3, pp. 280-299. | Africa, Lesotho | Deposit - Letseng |
DC201501-1687 2014 | Shore Gold Inc. | Shore Gold Inc. issued shares of Wescan Gold fields Inc. | Shore Gold Inc., Dec. 4, 1p. | Canada, Saskatchewan | News item - press release |
DC201501-1688 2014 | Shore Gold Inc. | Star-Orion South diamond project positive environmental decision from federal minister of environment. | Shore Gold Inc., Dec. 3, 1p. | Canada, Saskatchewan | News item - press release |
DC201502-1689 2014 | Shore Gold Inc. | Shore Gold announces closing of bought deal private placement. $ 5 million. | Shore Gold Inc., Dec. 30, 1p. | Canada, Saskatchewan | News item - press release |
DC201505-1690 2015 | Shore Gold Inc. | Announces year end results. Environmental assessment process and NI 43-101 and private placement $ 5.5 m. | Shore Gold Inc., Mar. 26, 8p. | Canada, Saskatchewan | News item - press release |
DC201506-1691 2015 | Shore Gold Inc. | Shore Gold Inc. announces first quarter results. | Shore Gold Inc., May 6, 3p. | Canada, Saskatchewan | News item - press release |
DC201509-1692 2015 | Shore Gold Inc. | Announces second quarter results. Completion of LDD on Orion South kimberlite; private placement. | Shore Gold Inc., Aug. 13, 3p. | Canada, Saskatchewan | News item - press release |
DC201510-2366 2015 | Shore Gold Inc. | Star-Orion South diamond drilling project Orion South large diameter drilling diamond results including 3.25, 1.15, 1.09 and 1.04 carat stones. | Shore Gold Inc., Sept. 2, 4p. | Canada, Saskatchewan | News item - press release |
DC201511-2405 2015 | Shore Gold Inc. | Star-Orion South diamond project diamond prices updated for revised mineral resource estimate. | Shore Gold Inc., Oct. 21, 4p. | Canada, Saskatchewan | News item - press release |
DC201512-2455 2015 | Shore Gold Inc. | Star-Orion South diamond project revised mineral resource estimate Star indicated: 28.2 Mct; Orion South indicated: 27.1 Mct. | Shore Gold Inc., Nov. 9, 3p. | Canada, Saskatchewan | News item - press release |
DC201512-2456 2015 | Shore Gold Inc. | Shore Gold Inc. announces third quarter results … revised mineral resources; updated valuation of diamond parcels; drilling results Orion South. | Shore Gold Inc., Nov. 12, 3p. | Canada, Saskatchewan | News item - press release |
DS201504-0217 2015 | Shu, Q., Brey, G.P. | Ancient mantle metsomatism recorded in subcalcic garnet xenocrysts: temporal links between mantle metasomatism, diamond growth and crustal tectonomagmatism. | Earth and Planetary Science Letters, Vol. 418, pp. 27-39. | Mantle | Metasomatism |
DS201512-1969 2015 | Simandl, G.J. | Carbonatites and related exploration targets. | Symposium on critical and strategic materials, British Columbia Geological Survey Paper 2015-3, held Nov. 13-14, pp. 31-38. | Global | Carbonatite |
| Abstract: Mineralized carbonatite systems are multi-commodity, highly sought after, but poorly understood exploration targets (Mariano, 1989a, b; Pell, 1996; Birkett and Simandl, 1999). They are the main sources of niobium and rare earth elements (REE), which are considered critical metals for some key economic sectors (European Commission, 2014), and have become popular exploration targets for junior mining companies worldwide. Carbonatites also contribute to our understanding of the Earth’s mantle (e.g., Bell and Tilton, 2001, 2002). Herein, we discuss the defi nition and classifi cation of carbonatites; summarize information pertinent for carbonatite exploration such as tectonic setting, shape, geophysical signature, associated rocks, alteration, and temporal distribution; and highlight the multi-commodity aspect of carbonatiterelated exploration targets and mineral prospectivity. 2. Defi nition and classifi cation Carbonatites are defi ned by the International Union of Geological Sciences (IUGS) as igneous rocks containing more than 50% modal primary carbonates (Le Maitre, 2002). Depending on the predominant carbonate mineral, a carbonatite is referred to as a ‘calcite carbonatite’ (sövite), ‘dolomite carbonatite’ (beforsite) or ‘ankerite carbonatite’. If more than one carbonate mineral is present, the carbonates are named in order of increasing modal concentrations, for example a ‘calcite-dolomite carbonatite’ is composed predominately of dolomite. If non-essential minerals (e.g., biotite) are present, this can be refl ected in the name as ‘biotite-calcite carbonatite’. Where the modal classifi cation cannot be applied, the IUGS chemical classifi cation is used (Fig. 1). This classifi cation subdivides carbonatites into calciocarbonatites, magnesiocarbonatites, and ferrocarbonatites. For calciocarbonatites, the ratio of CaO/(CaO+MgO+FeO +Fe2O3+MnO) is greater than 0.8. The remaining carbonatites are subdivided (based on wt.% ratios) into magnesiocarbonatite [MgO > (FeO+Fe2O3+MnO)] and ferrocarbonatite [MgO < (FeO+Fe2O3+MnO)] (Woolley and Kempe, 1989; Le Maitre, 2002). If the SiO2 content of the rock exceeds 20%, the rock is referred to as silicocarbonatite. When the IUGS chemical classifi cation is used, care should be taken to ensure that magnetite and hematite-rich calciocarbonates or magnesiocarbonatites are not erroneously classifi ed as ferrocarbonatites (Gittins and Harmer, 1997). A refi nement to the IUGS chemical classifi cation based on molar proportions (Gittins and Harmer, 1997), introduced ‘ferrugineous’ carbonatites (Fig. 2). The boundary separating calciocarbonatites from magnesiocarbonatites and ‘ferrugineous’ carbonatites is set at 0.75, above which carbonatites contain more than 50% calcite on a molar basis. Although not universally accepted, Gittins and Harmer’s classifi cation is commonly used in studies of carbonatitehosted ore deposits. A mineralogical-genetic classifi cation of carbonatites was proposed by Mitchell (2005). His paper points to pitfalls of the IUGS classifi cation and subdivides carbonatites into ‘primary carbonatites’ and ‘carbothermal residua’. The introduction of the term ‘carbothermal residua’ is signifi cant as it alerts mantle specialists to fundamental processes involved in the formation of many carbonatite-related deposits, and reduces rifts between camps of ore deposit geologists, petrologists, and mantle specialists. From the exploration |
DS201512-1970 2015 | Simandl, G.J., Akam, C., Paradis, S. | Selected critical materials: uses, markets, and resources. | Symposium on critical and strategic materials, British Columbia Geological Survey Paper 2015-3, held Nov 13-14 2015, pp. 1-4. | Global | Strategic materials |
DS201501-0032 2014 | Simonov, V.A., Prikhodko, V.S., Kovyazin, S.V., Kotlyarov, A.V. | Petrogenesis of meymechites of Sikhote Alin inferred from melt inclusions. | Russian Journal of Pacific Geology, Vol. 8, 6, pp. 423-442. | Russia | Meymechites |
DS201504-0218 2015 | Singh, A., Singh, C., Kennett, B.L.N. | A review of crust and upper mantle structure beneath the Indian subcontinent. | Tectonophysics, Vol. 644-645, pp. 1-21. | India | Geophysics - seismics, geothermometry |
DS201511-1880 2015 | Singh, A.P., Kumar, N., Zeyen, H. | Three dimensional lithospheric mapping of the eastern Indian Shield: a multi-parametric inversion approach. | Tectonophysics, Vol. 665, pp. 164-176. | India | Geophysics - seismics |
| Abstract: We analyzed satellite gravity and geoid anomaly and topography data to determine the 3D lithospheric density structure of the Singhbhum Protocontinent. Our density model shows that distinct vertical density heterogeneities exist throughout the lithosphere beneath the Singhbhum Protocontinent. The crustal structure identified includes a lateral average crustal density variation from 2800 to 2890 kg/m3 as well as a relatively flat Moho at 35-40 km depth in Singhbhum Protocontinent and Bastar Craton. A similar Moho depth range is found for the Mahanadi, Damodar, and Bengal basins. In the northern part of the area, Moho undulates between more than 40 km under the confluence of Mahanadi-Damodar Gondwana basins and the Ganga foreland basin, and 36-32 km under the Eastern Ghats Mobile belt and finally reaches 24 km in the Bay of Bengal. The lithosphere-asthenosphere boundary (LAB) across the Singhbhum Protocontinent is at a depth of about 130-140 km. In the regions of Bastar Craton and Bengal Basin, the LAB dips to about 155 ± 5 km depth. The confluence of Mahanadi and Damodar Gondwana basins toward the north-west and the foreland Ganga Basin toward the north are characterized by a deeper LAB lying at a depth of over 170 and 200 km, respectively. In the Bay of Bengal, the LAB is at a shallower depth of about 100-130 km except over the 85 0E ridge (150 km), and off the Kolkata coast (155 km). Significant density variation as well as an almost flat crust-mantle boundary indicates the effect of significant crustal reworking. The thin (135-140 km) lithosphere provides compelling evidence of lithospheric modification in the Singhbhum Protocontinent. Similarities between the lithospheric structures of the Singhbhum Craton, Chhotanagpur Gneiss Complex, and Northern Singhbhum Mobile Belt confirm that the repeated thermal perturbation controlled continental lithospheric modification in the Singhbhum Protocontinent. |
DS201506-0296 2015 | Singh, Slabunov | The central Bundelk hand Archean greenstone complex, Bundlekhand Craton, central India: geology, composition and geochronology of supracrustal rocks. | International Geology Review, Vol. 57, 11-12, pp. 1349-1364. | India | Craton |
DS201511-1881 2014 | Sivovolenko, S., Shelementiev, Y., Holloway, G., Mistry, J., Serov, R., Zhulin, S., Zipa, K. | How diamond performance attritbutes: brilliance, scintillation and fire depend on human vision features. | Australian Gemmologist, Vol. 25, 3, July-Sept. pp. | Technology | Diamond features |
| Abstract: This study describes how visual properties determine the perception of a diamond’s appearance and its performance attributes of brilliance, scintillation and fire, and how these influence beauty. Further articles will describe other parts of our cut study project. This research enables the development of methods and instruments for diamond performance analyses, shifting from current diamond cut rejection based tools, to diamond performance scoring systems, and the introduction of a new consumer language for communication between diamond buyers and sellers. The proposed Performance Scoring System is consumer friendly and can be used to design and manufacture new diamond cuts with improved optical appearance. |
DS201502-0102 2015 | Skuzovatov, S.Yu., Zedgenizov, D.A., Rakevich, A.L., Shatsky, V.S., Martynovich, E.F. | Multiple growth events in diamonds with cloudy Micro inclusions from the Mir kimberlite pipe: evidence from the systematics of optically active defects. | Russian Geology and Geophysics, Vol. 56, 1, pp. 330-343. | Russia | Deposit - Mir |
DS201503-0175 2015 | Smillie, I. | Radical collaboration: 10 years later. How a multi-stakeholder meeting lead to the creation and success of the diamond development initiative. | ddiglobal.org, Jan. 27, 3p. | Global | CSR |
DS201503-0176 2015 | Smillie, I. | The Tiffany & Co. foundation supports miner's registration project in DRC. | ddiglobal.org, Jan. 6, 1p. | Africa, Democratic Republic of Congo | CSR |
DS201504-0219 2015 | Smith, E.M., Kopylova, M.G., Frezzotti, M.L., Afanasiev, V.P. | Fluid inclusions in the Ebelyakh diamonds: evidence of CO2 liberation in eclogite and the effect of H2O on diamond habit. | Lithos, Vol. 216-217, pp. 106-117. | Russia | Deposit - Ebelyakh River |
DS201510-1804 2015 | Smith, L.j.D., Ptacek, C.J., Blowes, D.W., Groza, L.G., Moncur, M.C. | Perchlorate in lake water from an operating mine. Diavik | Environmental Science and Technology, Vol. 49, 13, pp. 7589-7596. | Canada, Northwest Territories | Deposit - Diavik |
| Abstract: Mining-related perchlorate [ClO4(-)] in the receiving environment was investigated at the operating open-pit and underground Diavik diamond mine, Northwest Territories, Canada. Samples were collected over four years and ClO4(-) was measured in various mine waters, the 560 km(2) ultraoligotrophic receiving lake, background lake water and snow distal from the mine. Groundwaters from the underground mine had variable ClO4(-) concentrations, up to 157 ?g L(-1), and were typically an order of magnitude higher than concentrations in combined mine waters prior to treatment and discharge to the lake. Snow core samples had a mean ClO4(-) concentration of 0.021 ?g L(-1) (n=16). Snow and lake water Cl(-)/ClO4(-) ratios suggest evapoconcentration was not an important process affecting lake ClO4(-) concentrations. The multiyear mean ClO4(-) concentrations in the lake were 0.30 ?g L(-1) (n = 114) in open water and 0.24 ?g L(-1) (n = 107) under ice, much below the Canadian drinking water guideline of 6 ?g L(-1). Receiving lake concentrations of ClO4(-) generally decreased year over year and ClO4(-) was not likely [biogeo]chemically attenuated within the receiving lake. The discharge of treated mine water was shown to contribute mining-related ClO4(-) to the lake and the low concentrations after 12 years of mining were attributed to the large volume of the receiving lake. |
DS201504-0220 2015 | SNL Metals & Mining | World exploration trends 2015 | SNL Metals Economics Group, March 3, 11p. | Global | Exploration - prices, budgets, arenas |
DS201503-0177 2015 | So, B-D., Yuen, D.A. | Generation of tectonic over-pressure inside subducting oceanic lithosphere involving phase-loop of olivine-wadsleyite transition. | Earth and Planetary Science Letters, Vol. 413, March 1, pp. 59-69. | Mantle | Subduction |
DS201502-0103 2015 | Sobolev, N.V., Dobretsov, N.I., Ohtani, E., Taylor, L.A., Schertl, H-P., Palyanov, Yu.N. | Problems related to crystallogenesis and the deep carbon cycle. | Russian Geology and Geophysics, Vol. 56, 1-2, pp. 1-12. | Mantle | Carbon cycle |
DS201510-1805 2015 | Sobolev, N.V., Sobolev, A.V., Tomilenko, A.A., Batanova, V.G., Tolstov, A.V., Logvinova, A.M., Kuzmin, D.V. | Unique compositional pecularities of olivine phenocrysts from the post flood basalt Diamondiferous Malokuonapskaya kimberlite pipe, Yakutia. | Doklady Earth Sciences, Vol. 463, 2, pp. 828-832. | Russia | Deposit - Malokuonapskaya |
DS201502-0104 2015 | Sobolev, N.V., Sobolev, A.V., Tomilenko, A.A., Kovyazin, S.V., Batanova, V.G., Kuzmin, D.V. | Paragenesis and complex zoning of olivine macrocrysts from unaltered kimberlite of the Udachnaya-East pipe, Yakutia: relationship with the kimberlite formation conditions and evolution. | Russian Geology and Geophysics, Vol. 56, 1, pp. 260-279. | Russia, Yakutia | Deposit - Udachnaya-East |
DS201510-1806 2015 | Sokol, A.G., Khokhryakov, A.F., Palyanov, Yu.N. | Composition of primary kimberlite magma: constraints from melting and diamond dissolution experiments. | Contributions to Mineralogy and Petrology, Vol. 170, 19p. | Russia | Deposit - Udachnaya |
| Abstract: Experiments are applied to constrain the composition of primary kimberlitic magmas which were in equilibrium with lithospheric peridotite and could resorb the entrained diamond to form typical dissolution features. The experiments are run on samples of a model carbonatite and a melt of the Udachnaya kimberlite at 6.3 GPa and 1400 °C, and at unbuffered or Re-ReO2-buffered oxygen fugacity (1-2 log units above Ni-O). Near-liquidus dry Fe3+-free carbonatitic melt (derived from carbonated harzburgite) is saturated with the Ol-Grt-Opx-Mgs assemblage and is almost inert to diamond. Carbonatitic melts that bear 4.6-6.8 wt% Fe2O3 or 1.5 wt% H2O are in equilibrium only with Mgs ± Ol near the liquidus. Dissolution of diamond by these melts produces surface textures uncommon (corrosion sculptures) or common (negative-oriented trigons, shield-shaped laminae and elongate hillocks) to kimberlitic diamonds. The near-liquidus melt of the Udachnaya kimberlite (Yakutia) with 10-12 wt% H2O is saturated with the Ol-Grt-px assemblage and may result from melting of carbonated garnet-bearing wehrlite. Hydrous kimberlitic melt likewise resorbs diamonds forming typical negative-oriented trigons, shield-shaped laminae and elongate hillocks on their surfaces. Therefore, the melts that could originate in the thermal conditions of subcratonic lithosphere, entrain diamond and dissolve it to produce dissolution features on crystal surfaces, were compositionally close to kimberlite (16-19 wt% SiO2) and rich in H2O. Dry Fe3+-bearing carbonatites with fO2 controlled by the ferric/ferrous equilibrium slightly above the Ni-NiO buffer cannot be diamond carriers. |
DS201502-0105 2015 | Sokol, A.G., Kruk, A.N. | Conditions of kimberlite magma generation: experimental constraints. | Russian Geology and Geophysics, Vol. 56, 1, pp. 245-259. | Mantle | Kimberlite genesis |
DS201509-0428 2015 | Sokol, A.G., Kruk, A.N., Chebotarev, D.A., Palyanov, Yu.N., Sobolev, N.V. | The composition of garnet as an indicator of the conditions of peridotite-carbonatite interaction in the subcratonic lithosphere ( Experimental data). | Doklady Earth Sciences, Vol. 463, 1, pp. 746-750. | Mantle | Garnet, carbonatite |
| Abstract: The article focuses on the study of composition of garnets of the lherzolitic and harzburgitic parageneses and the conditions of peridotite. As per the study, reconstruction of the conditions of metasomatism of peridotitic sources of kimberlite is possible in the evolution of garnet. It mentions the importance of dry and hydrous carbonatitic melt upon alteration of peridotitic sources of kimberlite as it acted as an another heat source. |
DS201512-1971 2015 | Solgadi, F., Groulier, P.A, Moukhsil, A., Ohnenstetter, D., Andre-Mayer, A.S., Zeh, A. | Nb-Ta-REE mineralization associated with the Crevier alkaline intrusion. | Symposium on critical and strategic materials, British Columbia Geological Survey Paper 2015-3, held Nov. 13-14, pp. 69-74. | Canada, Quebec | Alkalic |
| Abstract: The Crevier alkaline intrusion is in the Grenville Province, north of the Lac Saint-Jean region of Québec (Fig. 1). It covers ~25 km2 (Bergeron, 1980) and intrudes charnockitic suites in the allochthon belt defi ned by Rivers et al. (1989). This intrusion has a U-Pb zircon age of 957.5 ± 2.9 Ma (Groulier et al., 2014) and is oriented N320°, along the axis of crustal weakness known as the Waswanipi-Saguenay corridor (Bernier and Moorhead, 2000). This corridor is related to the Saguenay graben, which hosts the Saint-Honoré (Niobec) Nb-Ta-REE deposit and Montviel REE deposit. The age of the Saint-Honoré carbonatite was estimated at 584 to 650 Ma (K-Ar whole rock; Vallée and Dubuc, 1970; Boily and Gosselin, 2004). The Montviel intrusion has a U-Pb zircon age of 1894 ± 3.5 Ma (David et al., 2006; Goutier, 2006). These crystallization ages are very different and cannot be related to a single event for the injection of alkaline intrusions. As mapped by Bergeron (1980), the Crevier alkaline intrusion is broadly composed of syenite and carbonatite rocks (Fig. 2). The Nb- Ta mineralization consists of pyrochlore hosted by a nepheline syenite dike swarm in the centre of the intrusion. The highest REE concentrations, up to 729 ppm La and 1465 ppm Ce, are at the edge of the Crevier alkaline intrusion (Niotaz sud showing; Fig. 2). |
DS201502-0106 2015 | Sotnikova, I., Vladykin, N. | Genesis of rare metal pegmatites and alkaline fluorite rocks of Burpala Massif, northern Baikal folded zone. | Economic Geology Research Institute 2015, Vol. 17,, # 3020, 1p. Abstract | Russia | Carbonatite |
DS201504-0221 2015 | Souriau, A. | Presumption of large scale heterogeneity at the top of the outer core basal layer. | Earth and Planetary Science Letters, Vol. 415, April pp. 175-182. | Mantle | Core |
DM201502-1336 2015 | Spence, R. | Diamond mines of the world: 10 top ones ( three or four lines for the layman) on each. | Sprottglobal.com, Jan. 2p. | Global | News item - list of big mines |
DS201502-0107 2015 | Spetsius, Z.V., Bogush, I.N., Kovalchuk, O.E. | FTIR mapping of diamond plates of eclogitic and peridotitic xenoliths from Nyurbinskaya pipe, Yakutia: genetic implications. | Russian Geology and Geophysics, Vol. 56, 1, pp. 344-353. | Russia | Deposit - Nyurbinskaya |
DS201510-1807 2014 | Spetsius, Z.V., Polyanichko, V.V., Xarlamova, E.I., Tarskix, O.V., Ivanov, A.S. | Geology, petrography and mineralogy of the Zarya pipe kimberlites. | Deep-seated magmatism, its sources and plumes, Proceedings of XIII International Workshop held 2014., Vol. 2014, pp. 160-177. | Russia | Deposit - Zarya |
DS201502-0108 2015 | Spiegel, S.J. | Contested diamond certification: reconfiguring global and national interests in Zimbabwe's Marange fields. | Geoforum, Vol. 59, Feb. pp. 258-267. | Africa, Zimbabwe | Conflict Diamonds CSR |
DS201504-0222 2015 | Spiegl, T.C., Paeth, H., Frimmel, H.E. | Evaluating key parameters for the initiation of a Neoproterozoic Snowball Earth with a single Earth System Model of intermediate complexity. | Earth and Planetary Science Letters, Vol. 415, April pp. 100-110. | Mantle | Model |
DS201509-0429 2015 | Spivak, A., Solopova, N., Dubrovinsky, L., Litvin, Y. | Melting relations of multicompnent carbonate MgCO3-FeCO3-CaCO3-Na2CO3 system at 12-26 Gpa: application to deeper mantle diamond formation. | Physics and Chemistry of Minerals, DOI 10.1007/ s00269-015-0765-6 | Mantle | Melting |
| Abstract: Carbonatic components of parental melts of the deeper mantle diamonds are inferred from their primary inclusions of (Mg, Fe, Ca, Na)-carbonate minerals trapped at PT conditions of the Earth’s transition zone and lower mantle. PT phase diagrams of MgCO3-FeCO3-CaCO3-Na2CO3 system and its ternary MgCO3-FeCO3-Na2CO3 boundary join were studied at pressures between 12 and 24 GPa and high temperatures. Experimental data point to eutectic solidus phase relations and indicate liquidus boundaries for completely miscible (Mg, Fe, Ca, Na)- and (Mg, Fe, Ca)-carbonate melts. PT fields for partial carbonate melts associated with (Mg, Fe)-, (Ca, Fe, Na)-, and (Na2Ca, Na2Fe)-carbonate solid solution phases are determined. Effective nucleation and mass crystallization of deeper mantle diamonds are realized in multicomponent (Mg, Fe, Ca, Na)-carbonatite-carbon melts at 18 and 26 GPa. The multicomponent carbonate systems were melted at temperatures that are lower than the geothermal ones. This gives an evidence for generation of diamond-parental carbonatite melts and formation of diamonds at the PT conditions of transition zone and lower mantle. |
DS201510-1808 2015 | Spivak, A.V. | Genesis of superdeep diamond and inclusions from the Earth's lower mantle ( experimental research). IN RUSSIAN | Institute of Experimental Mineralogy, Russian Academy of Sciences, Chernogolova ( Moscow) IN RUSSIAN, 216p. Available pdf | Mantle | Diamond inclusions |
DS201511-1882 2015 | Spivak, A.V., Solopova, N.A., Dubrovinsky, L.S., Litvin, Yu.A. | The system MgCO3-FeCO3-CaCO3-Na2CO3 at 12-23 Gpa: phase relations and significance for the genesis of ultradeep diamonds. | Doklady Earth Sciences, Vol. 464, 1, pp. 946-950. | Mantle | Diamond genesis |
| Abstract: Physical-chemical experimental studies at 12-23 GPa of phase relationships within four-members carbonate system MgCO3-FeCO3-CaCO3-Na2CO3 and its marginal system MgCO3-FeCO3-Na2CO3 were carried out. The systems are quite representative for a set of carbonate phases from inclusions in diamonds within transitional zone and lower mantle. PT-phase diagrams of multicomponent carbonate systems are suggested. PT parameters of boundaries of their eutectic melting (solidus), complete melting (liquids) are established. These boundaries define area of partial melting. Carbonate melts are stable, completely mixable, and effective solvents of elemental carbon thus defining the possibility of ultra-deep diamonds generation. |
DS201511-1883 2015 | Spivak, A.V., Solopova, N.A., Dubrovinsky, L.S., Litvin, Yu.A. | Melting relations of multicomponent carbonate MgCOs-FeCO3-CaCO3-Na2COs system at 12-26 Gpa: application to deeper mantle diamond formation. | Physics and chemistry of Minerals, Vol. 42, 10, pp. 817-824. | Technology | Diamond genesis - experimental |
DS201509-0430 2015 | Srivastava, R.K., Gautam, G.C. | Geochemistry and petrogenesis of Paleo-Mesoproterozoic mafic dyke swarms from northern Bastar craton, central India: geodynamic implications in reference to Columbia supercontinent. | Gondwana Research, Vol. 28, pp. 1061-1078. | India | Dike swarms |
| Abstract: Field setting, petrography, geochemistry and available radiometric ages of Proterozoic mafic dykes from the northern Bastar craton have helped to identify four sets of mafic dykes; two Paleoproterozoic [viz. NW-SE North Bastar dykes (NBD) and ENE-WSW Dongargarh-Chhura dykes (DCD)] and two Mesoproterozoic [viz. 1.42 Ga ENE-WSW Bandalimal dykes (BDD) and 1.44 Ga N-S Lakhna dykes (LKD)]. Their petrographic and geochemical characteristics are very distinct and suggest their derivation from different mantle melts. Chemistry of all the four sets suggests different petrogenetic histories and samples of each distinct set are co-genetic nature. The NBD, the DCD and the BDD samples are sub-alkaline tholeiitic in nature, whereas the LKD samples show alkaline nature. Very distinct REE patterns are observed for all the four sets again suggesting their different petrogenetic histories. Geochemical comparison between the studied samples and mafic dyke samples of southern and central parts of the Bastar craton suggests very different picture for the northern Bastar craton. Only one set of northern Bastar dykes, i.e. the NBD, matches with BD1 dykes; no other dyke sets match with any of the dyke swarms identified in southern and central Bastar craton. Geochemically it is not straightforward to confirm crustal contamination, however, on the other hand, possibility of crustal contamination cannot be ruled out completely. A petrogenetic model based on trace element data suggests that all the four sets are derived from different mantle melts. The NBD and the DCD are probably generated within spinel stability field, whereas the BDD and the LKD may be derived from melts generated within garnet stability field. Available geological and geochemical data support the emplacement of studied dykes in a stable continental rift tectonic setting, however earlier intrusions have chemistry similar to N-MORB. The available geological, geochemical and geochronological data on the four indentified sets of mafic dykes from the northern Bastar craton indicate their relation to the assembly and break-up of Columbia supercontinent. |
DS201504-0223 2015 | Stachel, T., Luth, R.W. | Diamond formation - where, when and how? | Lithos, Vol. 220-223, pp. 200-220. | Mantle | Diamond inclusion, redox, geobarometry |
DS201512-1972 2015 | Stachel, T., Luth, R.W. | Diamond formation in Earth's mantle. | 43rd Annual Yellowknife Geoscience Forum Abstracts, abstract p. 98. | Mantle | Diamond genesis |
| Abstract: Studies of mineral inclusions in diamond have conclusively established that the principal diamond substrates in Earth's mantle are peridotitic (about 2/3) and eclogitic (about 1/3) domains located at 140-200 km depth in the subcratonic lithosphere. There, the formation of the dominant harzburgitic diamond association generally occurred under subsolidus (melt-absent) conditions. In eclogitic and lherzolitic substrates, however, diamond grew in the presence of a melt, with relatively rare exceptions relating to formation from strongly reducing fluids or at relatively low pressure (<50 kbar) and temperature (<1050°C). Complex internal growth structures indicate that in many instances, diamond formation did not occur in a single short lived event. The observed close agreement of radiometric ages involving different isotope systems and inclusion minerals for diamonds from individual occurrences, however, cannot be coincidental and implies that the temporal extent of individual diamond growth events is contained within the uncertainty of the age dates. Diamond formed through most of Earth's history, from the Paleoarchean to at least the Mesozoic. Diamond forming episodes occur on regional to global scales in response to tectonothermal events such as suturing, subduction and plume impact. Individual diamond forming episodes may be associated with particular substrates, with harzburgitic paragenesis diamonds generally yielding Paleoarchean (3.6-3.2 Ga) ages and lherzolitic paragenesis diamonds forming mostly in the Paleoproterozoic at ~2 Ga. Peridotitic diamond growth, however, continued through Earth's history, with the youngest age date being ~90 Ma. Formation of diamonds hosted by eclogite is documented from the Mesoarchean to the Neoproterozoic (2.9 and 0.6 Ga) and may well continue up to the present. Multiple lines of evidence suggest that formation of fibrous diamonds and diamond coats often is penecontemporaneous to kimberlite magmatism and hence, for the Central Slave, may even extent into the Tertiary. When it comes to the actual process(es) driving the precipitation of diamond, our knowledge is much less complete. Diamond grows during the infiltration of carbon-bearing fluids or melts into a suitable substrate. But what exactly is the diamond forming reaction that occurs there? The conventional view that redox reactions between percolating fluids/melts and wall rocks are nature's diamond recipe is inconsistent with both the low redox capacity of lithospheric mantle and the occurrence of large diamonds. Based on thermodynamic modeling, we instead propose that isochemical cooling or ascent of carbon-bearing fluids is a key mechanism of diamond formation. It operates particularly efficiently in chemically depleted mantle rocks (harzburgite), where a high melting temperature precludes dilution of the infiltrating fluid (see above), thereby explaining the long observed close association between diamond and harzburgitic garnet. |
DS201502-0109 2014 | Stacy, J., Stacey, A. | Perceptions of the impact of board members' individual perspectives on the social and environmental performance of companies. ( Based on SA and not junior companies). | Journal of the South African Institute of Mining and Metallurgy, Vol. 114, Nov. pp. 957-969. | Africa, South Africa | CSR |
DS201503-0179 2015 | Stagno, V., Frost, D.J., McCammon, C.A., Mohseni, H., Fei, Y. | The oxygen fugacity at which graphite or diamond forms from carbonate bearing melts in eclogitic rocks. | Contributions to Mineralogy and Petrology, Vol. 169, 18p. | Technology | Redox, carbonatite, geobarometry |
DS201505-0245 2015 | Stein, M. | Alkali basalts from the Golan and Galilee - signal from the early differentiation of the Earth mantle. | Israel Geological Society, Abstracts 1p. | Europe, Arabia, Nubian shield | Metasomatism |
DC201501-1693 2014 | Stellar Diamonds plc. | Significant increase in resource and diamond grade at Tongo kimberlite dyke project. | Stellar Diamonds plc., Nov. 28, 4p. | Africa, Sierra Leone | News item - press release |
DC201501-1694 2014 | Stellar Diamonds plc. | First diamond export from trial mining at Baolue kimberlite, Ghana. | Stellar Diamonds plc., Dec. 4, 3p. | Africa, Ghana | News item - press release |
DC201501-1695 2014 | Stellar Diamonds plc. | Positive study for acceleration of cash flows from surface mining at Tongo project Sierra Leone. | Stellar Diamonds plc., Dec. 3, 5p. | Africa, Sierra Leone | News item - press release |
DC201501-1696 2014 | Stellar Diamonds plc. | Loan facility with YA Global Master SPV Ltd. | Stellar Diamonds plc., Dec. 9, 3p. | Africa, Guinea | News item - press release |
DC201502-1697 2015 | Stellar Diamonds Plc. | Stellar Diamonds says Guinea trial mining on track: opts for larger Antwerp auction. Baoule | Stellar Diamonds Plc., Jan. 6, 1p. | Africa, Guinea | News item - press release |
DC201502-1698 2015 | Stellar Diamonds Plc. | Issue of equity… Fundraising…. For Baoule. | Stellar Diamonds Plc., Jan. 22, 2p. | Africa, Guinea | News item - press release |
DC201503-1699 2015 | Stellar Diamonds plc. | Stellar Diamonds plc. Annual report and update. Bauole pipe project. | Stellar Diamonds Plc., Feb. 18, 1p. | Africa, Guinea | News item - press release |
DC201504-1700 2015 | Stellar Diamonds Plc. | Diamond tender 6,031 carats. Baoule | Stellar Diamonds plc., Feb. 27, 1p. | Africa, Guinea | News item - press release |
DC201504-1701 2015 | Stellar Diamonds plc. | First diamond sales and revenues. 4,414 carats for $ US 417, 122. Baoule | Stellar Diamonds plc., Mar. 24, 1p. | Africa, Guinea | News item - press release |
DC201505-1702 2015 | Stellar Diamonds plc. | Interim results for the six months to 31 December 2014. Baoule, Tongo | Stellar Diamonds plc., Mar. 27, 3p. | Africa, Guinea, Sierra Leone | News item - press release |
DC201505-1703 2015 | Stellar Diamonds plc. | Interim results on Baoule, Tongo, finances. | Stellar Diamonds plc., Mar. 27, 13p. | Africa, Guinea, Sierra Leone | News item - press release |
DC201505-1704 2015 | Stellar Diamonds plc. | Application for mining licence at Tongo kimberlite project, Sierra Leone. | Stellar Diamonds plc., Apr. 1, 5p. | Africa, Sierra Leone | News item - press release |
DC201505-1705 2015 | Stellar Diamonds plc. | First 5000 carats achieved from trial mining at Baoule kimberlite, Guinea. | Stellar Diamonds plc., Apr. 20, 4p. | Africa, Guinea | News item - press release |
DC201506-1706 2015 | Stellar Diamonds plc. | Baoule diamond sale 4,439 carats to take place in Dubai and Antwerp. | Stellar Diamonds plc., May 7, 1p. | Africa, Guinea | News item - press release |
DC201506-1707 2015 | Stellar Diamonds plc. | Strong revenues from Baoule diamond auction. | Stellar Diamonds plc., May 28, 1p. | Africa, Guinea | News item - press release |
DC201507-1708 2015 | Stellar Diamonds plc. | Strong revenues from Baoule diamond auction. | Stellar Diamonds plc., May 28, 2p. | Africa, Guinea | News item - press release |
DC201509-1709 2015 | Stellar Diamonds plc. | Issue of convertible loan note , warrants and proposed capital re-organization, director's loan. Baoule and Tongo Dyke-1. | Stellar Diamonds plc., Aug. 14, 1p. | Africa, Guinea | News item - press release |
DC201509-1710 2015 | Stellar Diamonds plc. | Positive PEA on Tongo project and mining licence application, Sierra Leone. | Stellar Diamonds plc., Aug. 24, 3p. | Africa, Sierra Leone | News item - press release |
DC201512-2457 2015 | Stellar Diamonds plc. | Capital reorganization, funding update for Boule. | Stellar Diamonds plc., Nov. 19, 2p. | Africa, Sierra Leone | News item - press release |
DC201512-2458 2015 | Stellar Diamonds plc. | Final results and notices of AGM. Baoule, Tongo Dyke-1 | Stellar Diamonds plc., Nov. 24, 5p. | Africa, Sierra Leone | News item - press release |
DC201512-2459 2015 | Stellar Diamonds plc. | Submission of Tongo mining licence application and environmental impact assessment. | Stellar Diamonds plc., Nov. 27, 1p. | Africa, Sierra Leone | News item - press release |
DS201507-0337 2015 | Steyn, M. | A disgrace to the profession. The World's scientists, in their own words, on Michael E. Mann, his Hockey Stick and Their damage to Science. Vol. 1. | steynstore.com, Book $ 19.95 | Global | Climate change |
DS201511-1884 2015 | Stocklmayer, V., Stocklmayer, S. | A review of diamonds in Zimbabwe - a century on. | Australian Gemmologist, Vol. 25, 9, pp. 316-325. | Africa, Zimbabwe | History |
DM201501-1337 2014 | Stockwatch | CMKK's Turino loses detention appeal. | Stockwatch.com, Dec. 3, 1p. | United States | News item - CMKK |
DM201501-2474 2014 | Stockwatch | Northern Superior seeking JV for Ville Marie play in Quebec. Diamond Fields talking with contractor for dredging areas off coast of Namibia. Grizzly needs to resume work on claims. | Stockwatch.com, Nov. 28 2p. | Canada, Africa | News item - Northern Superior, Diamond Fields, Grizzly |
DM201503-1338 2015 | Stockwatch | ACS Archon sued by Fipke over Ekati legal fees. | Stockwatch.com, Feb. 3, 2p. | Canada, Northwest Territories | News item - Archon |
DM201505-1339 2015 | Stockwatch | Archon, Blussom deny owing Fipke's legal bill. | Stockwatch.com, Apr. 1, 1p. | Canada, Northwest Territories | News item - press release |
DM201505-2475 2015 | Stockwatch | Newstar Securities ( Robert Friedland) exercised options Peregrine Diamonds Ltd. | Stockwatch.com, Apr. 8, 1/2p. | Canada, Nunavut | News item - Peregrine |
DM201506-1340 2015 | Stockwatch | CMKM defendant Turino seeks freedom, again. | Stockwatch Diamonds & Specialty Minerals, May 21, 2p. | United States | News item - CMKM |
DM201511-2200 2015 | Stockwatch | CMKM Diamonds Inc. defendants moan about jail conditions. | Stockwatch.com, Sept. 28, 1p. | United States | News item - CMKM |
DS201512-1973 2015 | Stokes, L. | Kennady causes a commotion. A visit to the 'exciting' Kennady North project. | Diamonds in Canada Magazine, Northern Miner, Nov. pp. 10-13. | Canada, Northwest Territories | Deposit - Kennady North |
DM201506-1341 2015 | Stonechicky | Five yellow diamonds were registered last week at the Crater of Diamonds. Two weighed over a half carat each. | Stonechicky, Apr. 20, 1/4p. | United States, Arkansas | News item - Crater of Diamonds |
DC201501-1713 2014 | Stornoway Diamond Corporation | Stornoway announces second quarter 2015 results. | Stornoway Diamond Corporation, Dec. 15, 3p. | Canada, Quebec | News item - press release |
DC201504-1714 2015 | Stornoway Diamond Corporation | Stornoway commences pre-stripping at Renard -2 Renard -3 open pit. | Stornoway Diamond Corporation, Mar. 5, 1/4p. | Canada, Quebec | News item - press release |
DC201504-1715 2015 | Stornoway Diamond Corporation | Stornoway announces official opening of the "Clarence & Abel Swallow airport. | Stornoway Diamond Corporation, Mar. 25, 1p. | Canada, Quebec | News item - press release |
DC201505-1716 2015 | Stornoway Diamond Corporation | Stornoway announces funding of first tranche of stream financing. $ 80 million | Stornoway Diamond Corporation, Mar. 31, 2p. | Canada, Quebec | News item - press release |
DC201505-1717 2015 | Stornoway Diamond Corporation | Stornoway pours first concrete for the Renard diamond plant. | Stornoway Diamond Corporation, Apr. 7, 1p. | Canada, Quebec | News item - press release |
DC201506-1718 2015 | Stornoway Diamond Corporation | Stornoway announces investment by Blackstone Tactical Opportunities ( equity position) Renard | Stornoway Diamond Corporation, Apr. 30, 2p. | Canada, Quebec | News item - press release |
DC201507-1719 2015 | Stornoway Diamond Corporation | Stornoway announces fourth quarter and fiscal year 2015 results. Renard | Stornoway Diamond Corporation, June 17, 8p. | Canada, Quebec | News item - press release |
DC201510-2367 2015 | Stornoway Diamond Corporation | Stornoway announces updated Renard mineral resource estimate. Renard 2 21.6 m carats | Stornoway Diamond Corporation, Sept. 24, 3p. | Canada, Quebec | News item - press release |
DC201511-2406 2015 | Stornoway Diamond Corporation | Stornoway announces funding of second tranche of stream financing. Renard | Stornoway Diamond Corporation, Oct. 1, 3p. | Canada, Quebec | News item - press release |
DC201511-2407 2015 | Stornoway Diamond Corporation | Stornoway files Renard N!43-101 technical report, includes first estimate of exploration potential at Renard kimberlites. | Stornoway Diamond Corporation, Oct. 14, 4p. | Canada, Quebec | News item - press release |
DC201505-1720 2015 | Strike Diamond Corporation | Strike Diamond Corp. announces discovery of kimberlite indicator minerals at Sask. Craton properties ( Pikoo district). | Strike Diamonds Corporation, Mar. 30, 3p. | Canada, Saskatchewan | News item - press release |
DC201506-1721 2015 | Strike Diamond Corporation | Strike Diamond Corp. announces Pikoo property transaction with Wildcat Exploration Ltd. | Strike Diamond Corporation, May 14, 1p. | Canada, Saskatchewan | News item - press release |
DC201508-1722 2015 | Strike Diamond Corporation | Announces regulatory decision. Relief from forest fires near Pikoo. | Strike Diamond Corporation, July 20, 1p. | Canada, Saskatchewan | News item - press release |
DC201509-1723 2015 | Strike Diamond Corporation | Strike Diamond Corp. terminates proposed transaction with Wildcat Exploration Ltd. | Strike Diamond Corporation, Aug. 28, 1p. | Canada, Saskatchewan | News item - press release |
DC201510-2368 2015 | Strike Diamond Corporation | Strike Diamond Corp announces commencement of Pikoo airborne survey. | Strike Diamond Corporation, Sept. 16, 2p. | Canada, Saskatchewan | News item - press release |
DC201512-2460 2015 | Strike Diamond Corporation | Prongua Lake project update. Airborne survey. | Strike Diamond Corporation, Oct 29, 1p. | Canada, Saskatchewan | News item - press release |
DC201512-2461 2015 | Strike Diamond Corporation | Announes Pikoo airoborne results. | Strike Diamond Corporation, Nov. 17, 1p. | Canada, Saskatchewan | News item - press release |
DS201502-0110 2014 | Sun, J., Zhu, X., Chen, Y., Fang, N., Li, S. | Is the Bayan Obo ore deposit a micrite mound? A comparison with the Sailinhudong micrite mound. | International Geology Review, Vol. 56, 14, pp. 1720-1731. | China | Carbonatite |
DC201502-1724 2014 | Sunergy, Inc. | Sunergy and its partners complete cash sale of diamonds in 2014. | Sunergy, Inc., Dec. 31, 1p. | Africa, Sierra Leone, Liberia | News item - press release |
DC201506-1726 2015 | Sunergy, Inc. | Sunergy Management visits Sierra Leone and Liberia to consolidate equipment , finalize in country mining relations for 2015, and complete third diamond parcel shipment. | Sunergy, Inc., Aprl. 27, 2p. | Africa, Sierra Leone, Liberia | News item - press release |
DC201507-1725 2015 | Sunergy, Inc. | Sunergy has successfully closed the sale of both parcel 2 and 3 as of June 24. | Sunergy, Inc., June 25, 1p. | Africa, Liberia, Sierra Leone | News item - press release |
DC201506-1727 2015 | Sunrise Resources plc. | Half yearly highlights Cue. | Sunrise Resources plc., May 20, 3p. | Australia | News item - press release |
DC201507-1728 2015 | Sunrise Resources plc. | Cue (6 ppt slides) | Sunrise Resources plc., June 18, 33ppt. | Australia | News item - Sunrise |
DS201502-0111 2015 | Sushchevskaya, N., Melanholina, E., Belyatsky, B., Krymsky, R., Migdisova, N. | Oceanic magmatic evolution during ocean opening under influence of mantle plume. | Economic Geology Research Institute 2015, Vol. 17,, #3059, 1p. Abstract | India | Lamproite |
DS201512-1974 2015 | Sverjensky, D.A., Huang, F. | Diamond formation due to a pH drop during fluid-rock interactions. | Nature Communications, Nov. 3, 7p. | Technology | Diamond genesis |
| Abstract: Diamond formation has typically been attributed to redox reactions during precipitation from fluids or magmas. Either the oxidation of methane or the reduction of carbon dioxide has been suggested, based on simplistic models of deep fluids consisting of mixtures of dissolved neutral gas molecules without consideration of aqueous ions. The role of pH changes associated with water–silicate rock interactions during diamond formation is unknown. Here we show that diamonds could form due to a drop in pH during water–rock interactions. We use a recent theoretical model of deep fluids that includes ions, to show that fluid can react irreversibly with eclogite at 900?°C and 5.0?GPa, generating diamond and secondary minerals due to a decrease in pH at almost constant oxygen fugacity. Overall, our results constitute a new quantitative theory of diamond formation as a consequence of the reaction of deep fluids with the rock types that they encounter during migration. Diamond can form in the deep Earth during water–rock interactions without changes in oxidation state. |
DS201512-1975 2015 | Szuromi, P. | Solar cells. Perovskites go large. | Science, Vol. 350, 6263, p. 923. | Technology | Perovskite |
DM201506-1342 2015 | Tacy Ltd | The 2014 diamond pipeline.. Pace of retail growth continues to slide. | Diamond Intelligence Briefing, Vol. 30, 855, Apr. 27, pp. 4-11. | Global | News item - pipeline |
DS201501-0033 2014 | Takafuma, T. | Diamond Shades: Point of View .. Answers to 8 key questions on future of global diamond industry. | diamondshades.com, 90p. Pdf | Global | Overview |
DC201504-1729 2015 | Talmora Diamond Inc. | Talmora Diamond ennounces extension of warrants to 21 March 2016. | Talmora Diamond Inc., Mar. 12, 2p. | Canada, Northwest Territories | News item - press release |
DS201502-0112 2015 | Tamen, J., Nkoumbou, C., Reusser, E., Tchoua, F. | Petrology and geochemistry of mantle xenoliths from the Kapsiki Plateau ( Cameroon Volcanic Line): implications for lithospheric upwelling. | Journal of African Earth Sciences, Vol. 101, pp. 119-134. | Africa, Cameroon | Metasomatism |
DC201501-1730 2014 | Tango Mining Limited | Tango announces bulk sampling program at Oena project South Africa. | Tango Mining Limited, Dec. 1, 3p. | Africa, South Africa | News item - press release |
DC201504-1731 2015 | Tango Mining Limited | Bulk sampling program has commenced at Oena project, South Africa. | Tango Mining Limited, Mar. 3, 1p. | Africa, South Africa | News item - press release |
DC201508-1732 2015 | Tango Mining Limited | Oena operational. | Tango Mining Limited, July 6, 3p. | Africa, South Africa | News item - press release |
DC201508-1733 2015 | Tango Mining Limited | Tango to acquire BK11 diamond mine, Botswana from Firestone. | Tango Mining Limited, July 9, 2p. | Africa, Botswana | News item - press release |
DC201509-1734 2015 | Tango Mining Limited | Oena operational update and diamond sales. Orange River alluvials. | Tango Mining Limited, Aug. 5, 1p. | Africa, South Africa | News item - press release |
DC201509-1735 2015 | Tango Mining Limited | Tango annnounces resource estimate for BK11 kimberlite diamond mine, Botswana. | Tango Mining Limited, Aug. 24, 3p. | Africa, Botswana | News item - press release |
DC201511-2408 2015 | Tango Mining Limited | Tango announces Oena bulk sampling program to recommence. | Tango Mining Limited, Oct. 6, 1p. | Africa, South Africa | News item - press release |
DC201511-2409 2015 | Tango Mining Limited | Tango announces positive NI43-101 PEA for BK11 kimberlite diamond mine, Botswana and updated acquisition terms with Firestone. | Tango Mining Limited, Oct. 13, 2p. | Africa, Botswana | News item - press release |
DC201511-2410 2015 | Tango Mining Limited | Bulking up its diamond division. BK11 and Oena | Hallgarten & Company, Oct. 21, 16p. | Africa, Botswana, South Africa | News item - Tango |
DS201512-1976 2016 | Tappe, S., Smart, K.A., Stracke, A., Romer, R.L., Prelevic, D., van den Bogaard, P. | Melt evolution beneath a rifted carton edge: 40Ar/39/Ar geochronology and Sr-Nd-Hf-Pb isotope systematics of primitive alkaline basalts and lamprophyres from the SW Baltic Shield. | Geochimica et Cosmochimica Acta, Vol. 173, pp. 1-36. | Europe, Sweden | Alkalic |
DS201510-1809 2015 | Tappert, M. | Advancements in hyderspectral drill core imaging of kimberlites: examples from Snap Lake and Tango Extension. | Vancouver Kimberlite Cluster, Sept. 23, 1p. Abstract | Canada, Northwest Territories | Deposit - Snap Lake, Tango Extension |
DS201508-0377 2015 | Tappert, M.C., Rivard, B., Fulop, A., Rogge, D., Feng, J., Tappert, R., Stalder, R. | Characterizing kimberlite dilution by crustal rocks at the Snap Lake diamond mine ( Northwest Territories, Canada) using SWIR ( 1.90-2.36 um) and LWIR ( 8.1-11.1um) hypersprectal imagery collected from drill core. | Economic Geology, Vol. 110, 6, Sept-Oct. pp. 1375-1387. | Canada, Northwest Territories | Deposit - Snap Lake |
DS201512-1977 2015 | Tappert, R., Tappert, M.C. | hyper spectral imagery: a novel way to analyze kimberlite indicator minerals and to detect kimberlite micro-float. | 43rd Annual Yellowknife Geoscience Forum Abstracts, abstract p. 102. | Canada, Northwest Territories | Hyperspectral imagery |
| Abstract: The collection and analysis of kimberlite indicator minerals from heavy mineral concentrates is an integral part of the diamond exploration process. However, surficial sampling programs are often restricted by time-consuming mineral collection, processing, and analysis procedures. To facilitate the development of a technique that can simplify and accelerate the identification and classification of kimberlite indicator minerals, we explored the usage of hyperspectral imagery, which is based on the analysis of reflected radiation in the visible and infrared parts of the electromagnetic spectrum. The investigation was focused on the identification of indicator garnets. Hyperspectral imagery was collected directly from heavy mineral concentrates, and these images were de-noised and processed to isolate the spectral absorption features relating to mineral composition. These images were then analyzed to identify individual garnets. This portion of the analysis was complemented by the results of 1000+ high-resolution spectra collected from well-characterized crust- and mantle-derived garnets to ensure that the garnets in the heavy mineral concentrates were accurately identified. Preliminary results indicate that garnets can be readily distinguished from other concentrate minerals using hyperspectral imagery, and that the garnets can also be compositionally classified. The compositional classification allows crust- and mantle-derived garnets to be distinguished accurately, while providing concentration information about certain transition elements, like chromium and titanium. In addition to the garnet analysis, hyperspectral imagery was also used to identify millimeter-sized fragments of kimberlite (kimberlite micro-float) in heavy mineral concentrates and unprocessed sediment samples. Preliminary results indicate that kimberlite micro-float can be readily distinguished from other rock and mineral fragments due to its distinct spectrum. Pending additional testing, analytical techniques using hyperspectral imagery may serve as an alternative to the costly and time-consuming indicator mineral identification methods currently being used. |
DS201504-0224 2015 | Tarakanov, R.Z., Veselov, O.V., Andreeva, M.Yu. | The possible boundary of phase transitions at a depth of 350 km in the transition zone between continents and oceans. | Doklady Earth Sciences, Vol. 460, 2, pp. 159-162. | Russia, Far East | Geophysics - seismics |
DS201509-0431 2015 | Tarduno, J. | An older geomagnetic field suggests an early start to plate tectonics. ( Jack Hills) | Physics.org , Aug. 3, 1p. | Australia | Geophysics - magnetics |
DS201509-0432 2015 | Tarduno, J.A., Cottrell, R.D., Davis, W.J., Nimmo, F., Bono, R.K. | A Hadean to Paleoarchean geodynamo recorded by single zircon crystals. ( Jack Hills) | Science, Vol. 349, 6247, pp. 521-524. | Mantle | Geodynamo |
| Abstract: Knowing when the geodynamo started is important for understanding the evolution of the core, the atmosphere, and life on Earth. We report full-vector paleointensity measurements of Archean to Hadean zircons bearing magnetic inclusions from the Jack Hills conglomerate (Western Australia) to reconstruct the early geodynamo history. Data from zircons between 3.3 billion and 4.2 billion years old record magnetic fields varying between 1.0 and 0.12 times recent equatorial field strengths. A Hadean geomagnetic field requires a core-mantle heat flow exceeding the adiabatic value and is suggestive of plate tectonics and/or advective magmatic heat transport. The existence of a terrestrial magnetic field before the Late Heavy Bombardment is supported by terrestrial nitrogen isotopic evidence and implies that early atmospheric evolution on both Earth and Mars was regulated by dynamo behavior. |
DS201511-1886 2015 | Tarum, A., Lee, S.J., Yap, C.M., Finkelstein, K.D., Misra, D.S. | Impact of impurities and crystal defects on the performance of CVD diamond detectors. | Diamond and Related Materials, in press available, 6p. | Technology | Synthetics - Radiation detectors |
| Abstract: Radiation detectors based on diamond are highly favored for particle physics research due to the superior radiation hardness. In this work, we investigate the influence of impurities and crystalline imperfections on the charge collection efficiency (CCE) of single crystal diamond. Seventeen (17) ultra-low fluorescent diamond samples grown by microwave plasma chemical vapor deposition method from IIa Technologies PTE LTD are pre-selected for this study. The measured CCE of all samples using 241Am (?-particles) as ionizing source are analyzed together with the concentration of trace impurities and crystalline imperfection in the crystal. The amounts of impurities are quantified from integrated fluorescence intensity arising from the nitrogen vacancies (NV) created during different CVD growth process conditions. The crystal imperfections are assessed by X-ray rocking curves from X-ray topography images obtained at the Cornell High Energy Synchrotron Source. The CCE decays rapidly as the intensity of NV (INV), phonon sideband approaches that of diamond 2nd order Raman peak which follows the relation: View the MathML sourceCCEINV=100/1+INV1.052. The energy resolution, ?E/E (ratio of the energy spectrum width to the most probable peak) highly correlates with broader rocking curve width distribution. Prime novelty statement: This work provides an understanding on the most important factors that contribute to degradation of charge collection efficiency (CCE) in diamond based detectors and sensors. The CCE decays rapidly as the intensity of nitrogen vacancy phonon sideband approaches that of diamond 2nd order Raman peak which follows the relation: View the MathML sourceCCEINV=100/1+INV1.052. The energy resolution, that is the ratio of the energy spectrum width to the most probable peak, highly correlates with broader X-ray rocking curve width distribution. |
DS201504-0225 2015 | Tateno, S., Kuwayama, Y., Hirose, K., Ohishi, Y. | The structure of Fe-Si alloy in Earth's inner core. | Earth and Planetary Science Letters, Vol. 418, pp. 11-18. | Mantle | Core |
DS201512-1978 2015 | Taylor, L.A., Logvinova, A.M., Howarth, G.H., Liu, Y., Peslier, A.H., Rossman, G.R., Guan, Y., Chen, Y., Sobolev, N.V. | Low water contents in diamond mineral inclusions: proto-genetic origin in a dry cratonic lithosphere. | Earth and Planetary Science Letters, Vol. 433, pp. 125-132. | Mantle | NAMs Nominally Anhydrous Minerals |
| Abstract: The mantle is the major reservoir of Earth's water, hosted within Nominally Anhydrous Minerals (NAMs) (e.g., , , and ), in the form of hydrogen bonded to the silicate's structural oxygen. From whence cometh this water? Is the water in these minerals representative of the Earth's primitive upper mantle or did it come from melting events linked to crustal formation or to more recent metasomatic/re-fertilization events? During diamond formation, NAMs are encapsulated at hundreds of kilometers depth within the mantle, thereby possibly shielding and preserving their pristine water contents from re-equilibrating with fluids and melts percolating through the lithospheric mantle. Here we show that the NAMs included in diamonds from six locales on the Siberian Craton contain measurable and variable H2O concentrations from 2 to 34 parts per million by weight (ppmw) in olivine, 7 to 276 ppmw in clinopyroxene, and 11-17 ppmw in garnets. Our results suggest that if the inclusions were in equilibrium with the diamond-forming fluid, the water fugacity would have been unrealistically low. Instead, we consider the H2O contents of the inclusions, shielded by diamonds, as pristine representatives of the residual mantle prior to encapsulation, and indicative of a protogenetic origin for the inclusions. Hydrogen diffusion in the diamond does not appear to have modified these values significantly. The H2O contents of NAMs in mantle xenoliths may represent some later metasomatic event(s), and are not always representative of most of the continental lithospheric mantle. Results from the present study also support the conclusions of Peslier et al. (2010) and Novella et al. (2015) that the dry nature of the SCLM of a craton may provide stabilization of its thickened continental roots. |
DM201506-1343 2015 | The Herald | Zim earns bargaining power for diamonds. | Allafrica.com, May 19, 1/4p. | Africa, Zimbabwe | News item - legal |
DM201510-2106 2015 | The Independent | The tragic saga of Marange . ( history from 2000 on) | theIndependent.co.zw, Sept. 4, 1p. | Africa, Zimbabwe | News item - Marange |
DM201512-2317 2015 | The India Times | A new Siberian ice diamond created by Russian scientists will prove to be a game changer for the domestic industry. Cost around 1- 2 % of real. | TheIndiatimes.com, Nov. 16, 1/4p. | Russia | News item - synthetics |
DM201505-1344 2015 | The Isareli Diamond Industry | Coronet gets Guiness world record for $ 2 million diamond guitar. | israelidiamond.co.il, Mar. 24, 1/4p. | Technology | News item - guitar |
DM201505-1345 2015 | The Isareli Diamond Industry | Antwerp police commissioner and diamond squad head arrested ( $ 55,000 diamonds and gold in his home) | israelidiamond.co.il, Mar. 25, 1/4p. | Europe, Belgium | News item - legal |
DM201503-1346 2015 | The Israeli Diamond Industry | Louisiana man finds 2.01 carat diamond in Arkansas state park. | israelidiamond.co.il, Feb. 8, 1/4p. | United States, Arkansas | News item - Crater of Diamonds |
DM201503-1347 2015 | The Israeli Diamond Industry | India to certify 30,000 diamond polishers as "diamond artisans". | israelidiamond.co.il, Feb. 10, 1/4p. | India | News item - polishing |
DM201503-1348 2015 | The Israeli Diamond Industry | The mystery that still baffles scientists: what makes pink diamonds pink? | israelidiamond.co.il Blog Stonehicky, Jan. 1, 1/4p. | Australia | News item - pink diamonds |
DM201504-1349 2015 | The Israeli Diamond Industry | Angola tax changes out of sync with country's mining code. | israelidiamond.co.il, Mar. 11, 1/4p. | Africa, Angola | News item - legal |
DM201505-1350 2015 | The Israeli Diamond Industry | A summary of 2014 and forecast for 2015. | israelidiamond.co.il, Apr. 13, 1p. | Global | News item - prices |
DM201506-1351 2015 | The Israeli Diamond Industry | 5 yellow diamonds found at Arkansas Crater Park in a week. Historical coverage. | israelidiamond.co.il, Apr. 20, 1/2p. | United States, Arkansas | News item - Crater of Diamonds |
DM201506-1352 2015 | The Israeli Diamond Industry | Diamond Corp recovers 19.83 carat diamond from Lace mine. | israelidiamond.co.il, Apr. 30, 1/4p. | Africa, South Africa | News item - DiamondCorp |
DM201506-1353 2015 | The Israeli Diamond Industry | Scientist discovers a "diamond finding plant" in Liberia ( Haggerty) | israelidiamond.co.il, May 6, 1/4p. | Africa, Liberia | News item - botany |
DM201507-1358 2015 | The Israeli Diamond Industry | 1.3 million carats a year: the Aikhal diamond mine. | israelidiamond.co.il, June 1, 1/4p. | Russia | News item - Alrosa |
DM201507-1359 2015 | The Israeli Diamond Industry | Zimbabwe orders Anjin to reinstate 1,100 employees. | israelidiamond.co.il, June 10, 1/4p. | Africa, Zimbabwe | News item - Anjin |
DM201507-1360 2015 | The Israeli Diamond Industry | The world's top miners lost $ 156 billion in market value in 2014. | israelidiamond.co.il, June 9, 1/4p. | Global | News item - economics |
DM201508-1354 2015 | The Israeli Diamond Industry | Angola's private gem: The Luarica diamond mine. | israelidiamond.do.il, June 29, 1/4p. | Africa, Angola | News item - Endiama, Trans Hex |
DM201509-1355 2015 | The Israeli Diamond Industry | We didn’t see, we didn’t hear. We just talked. Presidents meeting. | israeildiamond.co.il, Aug. 3, 2p. | Europe, Israel | News item - industry |
DM201509-1356 2015 | The Israeli Diamond Industry | De Beers: medium to long term outlook for diamonds extremely positive. | israeildiamond.co.il, Aug. 11, 1/4p. | Global | News item - De Beers |
DM201509-1357 2015 | The Israeli Diamond Industry | Lucapa recovers 5 large special diamonds at Lulo. BLK-08 | israeildiamond.co.il, Aug. 20, 1/4p. | Africa, Angola | News item - Lucapa |
DM201510-2107 2015 | The Israeli Diamond Industry | Fair price and best value in large fancy yellow and white stones. | israeildiamond.co.il, Sept. 16, 1p. | Global | News item - prices, supply, demand |
DM201511-2201 2015 | The Israeli Diamond Industry | The gem of southern Africa: Namibian diamonds. | israelidiamond.co.il, Oct. 14, 1p. | Africa, Namibia | News item - Namdeb |
DM201511-2202 2015 | The Israeli Diamond Industry | Diamonds detect early stage cancer. ( MRI scans) | israelidiamond.co.il, Oct. 15, 1/2p. | Technology | News item - MRI scans |
DM201512-2318 2015 | The Israeli Diamond Industry | EU not expected to regulate conflict diamonds until mid-2016. | israelidiamond.co.il, Oct. 28, 1/4p. | Global | News item - legal |
DM201512-2319 2015 | The Israeli Diamond Industry | Africa's troublemakers: history of diamonds in the Central African Republic. | israelidiamond.co.il, Nov. 11, 1p. | Africa, Central African Republic | News item - KP |
DM201512-2320 2015 | The Israeli Diamond Industry | Scientists smash an 8 carat diamond to discover secrets within. Dating clinopyroxene (Namakwa Diamonds donated diamond). | israelidiamond.co.il, Nov. 19, 1p. | Technology | News item - Namakwa |
DS201508-0378 2015 | The Israeli Diamond Industry | Top 10 most expensive diamonds in the world: Millenium Star, Koh-i-Noor, Culinan, Hope, Centenary, Shawish ring, Pink Star, Beau Sancy, Moussaieff Red, Graff Pink. | israelidiamond.co, June 29, 2p. | Global | Diamonds notable - prices |
DM201506-1361 2015 | The New York Times | Changes are reshaping the world's diamond market. | The New York Times, May 13, 2p. | Global | News item - markets |
DM201512-2321 2015 | The New York Times | Borrowing from solar and chip tech to make diamonds faster and cheaper. ( before Nanosolar) now Diamond Foundry | The New York Times, Nov. 11, 6p. | Technology | News item - Diamond Foundry |
DM201509-1362 2015 | The Siberian Times | Russia reveals 'unique diamonds' created by gases and lightning from volcanic eruption. | The Siberian Times, July 27, 10p. | Russia, Kamchatka | News item - Tolbachik |
DM201506-1363 2015 | The Standard | Bikita Diamonds - a tale of shady deals. | Allafrica.com, May 17, 1/4p. | Africa, Zimbabwe | News item - Bikita |
DM201505-1364 2015 | The Swazi Observer | Dvololwako diamond mine to be revived this year…. ( again?) | observer.org.sz, Mar. 25, 1/4p. | Africa, Swaziland | News item - Dvokolwayo |
DM201509-1365 2015 | The Washington Post | The dangerous search for emeralds in Colombia. After taking over a major mine, a U.S. Company ( MTC) has met with violence. | The Washington Post, reprint Republicofmining.com, Aug. 9, 8p. | South America, Colombia | News item - emeralds |
DM201508-1366 2015 | The West Australian | Marmion enters Ellendale fray. ( Mines Minister) | The West Austrailan Newspaper, July 13, 1p. | Australia | News item - Kimberley Diamonds |
DM201509-1367 2015 | The West Australian | KDL offer to retake Ellendale. | The West Australian Newspaper, July 8, 1/2p. | Australia | News item - Kimberley Diamonds |
DM201509-1368 2015 | The West Australian | Ellendale assets go ahead of collapse. | The West Australian Newspaper, July 8, 1/2p. | Australia | News item - Kimberley Diamonds |
DM201509-1369 2015 | The West Australian | tax payers take Kimberley Diamonds' Ellendale hit. | The West Australian Newspaper, July 4, 1p. | Australia | News item - Kimberley Diamonds |
DM201509-1370 2015 | The West Australian | Late KDL payments irk DMP. | The West Australian Newspaper, July 4-5, p. 101. | Australia | News item - Kimberley Diamonds |
DM201509-1371 2015 | The West Australian | Marmion enters Ellendale fray. ( Mines Minister DMP) | The West Australian Newspaper, July, 13, p. 56. | Australia | News item - Kimberley Diamonds |
DM201509-1372 2015 | The West Australian | Precious little left to salvage. ( Ellendale - details of Goodrich Resources ) | The West Australian Newspaper, July 11-12, p. 99. | Australia | News item - Kimberley Diamonds |
DM201509-1373 2015 | The West Australian | ASIC probes Kimberley after Ellendale collapse. ( Owed to staff… ) | The West Australian Newspaper, July 16, p. 46. | Australia | News item - Kimberley Diamonds |
DS201509-0433 2015 | Thiery, V., Rolin, P., Dubois, M., Caumon, M-C. | Discovery of metamorphic microdiamonds from the parautochthonous units of the Variscan French Massif Central. | Gondwana Research, Vol. 28, pp. 954-960. | Europe, France | Microdiamonds |
| Abstract: The Variscan French Massif Central (FMC) is classically described as a stack of nappes with increasing metamorphism from the bottom (parautochthonous unit) to the top (lower and upper gneiss units). Ultra-high pressure (UHP) metamorphism was already recognized in the uppermost units, with notably coesite-bearing rocks. We report the first finding of metamorphic microdiamonds in the parautochthonous unit, revealing that the UHP event affected the whole stack of nappes and also that the pressures reached are above what was previously expected, since the presence of diamond, according to the peak temperature estimates for this unit, indicates pressures of ca. 3 GPa (i.e. 100 km depth). At the scale of the FMC, this finding adds complexity to the established models. On a broader scale, this adds evidence of similarity between this part of the belt and other UHP Variscan terranes such as the Erzgebirge and the Bohemian Massif. |
DS201502-0113 2014 | Thomson, A.R., Kohn, S.C., Bulanova, G.P., Smith, C.B., Araujo, D., EMIF, Walter, M.J. | Origin of sub-lithospheric diamonds from the Juina-5 kimberlite ( Brazil): constraints from carbon isotopes and inclusion compositions. | Contributions to Mineralogy and Petrology, Vol. 168, pp. 1081-1110. | South America, Brazil | Deposit - Juina-5 |
DM201502-1374 2014 | Tian, L. | Supply factors tarnish India's diamond sector. | Globaltimes.cn, Dec. 29, 2p. | India | News item - rough demand |
DS201506-0297 2015 | Tian, Y., Yang, J., Robinson, P.T., Xiong, F., Li, Y., Zhang, Z., Liu, Z., Liu, F., Niu, X. | Diamond discovered in high Al chromitites of the Sartohay ophiolite, Xinjiang province China. | Acta Geologica Sinica, Vol. 89, 2, pp. 332-340. | China | Chromitite |
DM201509-1375 2015 | Time Magazine | Blood Diamonds …. Congolese miners working one of the thousands of artisanal mines that cover the country. | Time Magazine, Aug. 18p. | Africa, Democratic Republic of Congo | News item - history |
DS201503-0180 2015 | Titkov, S.V., Mineeva, R.M., Zudina, N.N., Sergeev, A.M., Ryabchikov, I.D., Shiryaev, A.A., Speransky, A.V., Zhikhareva, V.P. | The luminescent nature of orange coloration in natural diamonds: optical and EPR study. | Physics and Chemistry of Minerals, Vol. 42, 2, pp. 131-144. | Technology | Diamond Colour |
DS201502-0114 2015 | Titkov, S.V., Shiryaev, A.A., Zudina, N.N., Zudin, N.G., Solodova, Yu.P. | Defects in cubic diamonds from the placers in the northeastern Siberian platform: results of IR microspectrometry. | Russian Geology and Geophysics, Vol. 56, 1, pp. 354-365. | Russia | Diamond morphology |
DS201502-0115 2015 | Tkalcic, H. | Complex inner core of the Earth: the last frontier of global seismology. | Reviews of Geophysics, Vol. 53, 1, pp. 59-94. | Mantle | Geophysics - seismics |
DS201505-0247 2015 | Toledo, V., Apter, D.B., Ward, J. | High pressure indicator minerals from the Rakefet magmatic complex ( RMC), Mt. Carmel, Israel. | Israel Geological Society, 1p.poster | Europe, Israel | Mineralogy |
DS201505-0248 2015 | Toledo, V., Ward, J., de Wit, M., Spaggiari, R., Coopersmith, H., Wald, R. | A transient fluvial placer in the mid reach of the Kishon Valley northern Israel: initial results of follow up exploration. | Israel Geological Society, 1p.poster | Europe, Israel | Exploration results |
DM201508-1376 2015 | Toronto Star | A diamond mine isn't forever… a full page on Kimberley SA | Toronto Star Newspaper, July 4, 1 page. | Africa, South Africa | News item - Kimberley |
DM201511-2203 2015 | Toronto Star | A rough reception for diamond giant in Cree community. Residents of Peawanuck watch warily as De Beers eyes new prospects in northern Ontario. | Toronto Star Newspaper, Oct. 11, 5p. | Canada, Ontario | News item - De Beers |
DM201511-2204 2015 | Toronto Star | Documentary film looks at effects of mine on Attawapiskat. | Toronto Star Newspaper, Oct. 22, 1p. | Canada, Ontario, Attawapiskat | News item - Victor |
DM201512-2322 2015 | Toronto Star | De Beers seeks First Nation exploration support. A De Beers Canada is visiting remote Weenusk First Nation. Victor area | The Toronto Star Newspaper, Nov. 18, 1p. | Canada, Ontario, Attawapiskat | News item - De Beers |
DC201507-1736 2015 | Trans Hex Group Limited | Update on Baken, Bloeddrif, Somiluana, Namaqualand ( Kleinzee, Mitchell's Bay, Koingraas | Trans Hex Group, June 5, 1p. | Africa, South Africa, Angola | News item - press release |
DC201507-1737 2015 | Trans Hex Group Limited | Trans Hex 'will not overpay' for De Beers unit ( Kimberley Tailings operation). | Trans Hex Group, June 2, 1/2p. | Africa, South Africa | News item - press release |
DS201512-1979 2015 | Tremblay, J., Bedard, L.P., Matton, G. | A petrographic study of Nb-bearing minerals at the Saint-Honore niobium deposit. | Symposium on critical and strategic materials, British Columbia Geological Survey Paper 2015-3, held Nov. 13-14, pp. 75-82. | Canada, Quebec | Niobium |
| Abstract: The mineralogy of rare earth element (REE) ore deposits is critical in understanding their petrogenesis but also has signifi cant implications for metallurgy. Like many ore deposits, high-grade rocks do not necessarily equate to positive economic viability and this is especially true for REE deposits. Consequently, knowledge of sample mineralogy acquired early in a project’s life can lead to more effi cient exploration programs through confi rmation of either ‘good’ or ‘bad’ mineralogy. Many REE minerals show fi ne grain sizes and their accumulation can be diffi cult to recognize in hand sample or drill core with an unaided eye. Knowledge of their distribution before sampling can ensure that the best rocks or core lengths are sampled for petrographic or detailed study. REE minerals generally have complex yet diagnostic absorption patterns in visible to shortwave infrared (VNIRSWIR) refl ectance spectra that are driven primarily by REErelated 4f-4f intraconfi gurational electronic transitions. Our recent research (Turner et al., 2014, Turner 2015) has focused on three important mineral classes: REE fl uorocarbonates (bastnaesite, synchysite, and parisite), REE phosphates (monazite, xenotime, and britholite), and REE-bearing silicates (cerite, mosandrite, kainosite, zircon and eudialyte). Refl ectance spectra were acquired in the visible to short wave infrared regions (500 nm to 2500 nm) and samples were characterized using scanning electron microscopy and electron microprobe analysis. The results of our work and publications from other research groups (e.g., Rowan et al., 1986, Swayze et al., 2013, Hoefen et al., 2014, Boesche et al., 2015) have shown the strong applicability of refl ectance spectroscopy and hyperspectral imaging to understanding, exploring, and exploiting rare earth element ore deposits and their associated rocks. |
DC201504-1738 2015 | Trigold Resources Inc. | Trigold signs letter of intent on diamond project. Rush, James River and Muskox kimberlites. | Trigold Resources Inc., Mar. 13, 2p. | Canada, Nunavut | News item - press release |
DC201506-1739 2015 | Trigold Resources Inc. | Trigold signs agreement on advanced diamond projects. Rush, James River and Muskox. | Trigold Resources Inc., May 6, 2p. | Canada, Nunavut | News item - press release |
DC201511-2411 2015 | Trigold Resources Inc. | Trigold changes name to Crystal Exploration Inc. Finalizing acquisition of Rush, James River and Muskox. | Trigold Resources Inc., Oct. 14, 1p. | Canada, Northwest Territories | News item - press release |
DS201502-0116 2014 | Trubitsyn, V.P., Evseev, M.N. | Mantle plumes at the boundary of the Upper and Lower mantle. | Doklady Earth Sciences, Vol. 459, 1, pp. 1397-1399. | Mantle | Hotspots |
DS201510-1810 2015 | Trubitsyn, V.P., Evseev, M.N., Trubitsyn, A.P. | Influence of continents and lithospheric plates on the shape of D" layer and the spatial distribution of mantle plumes. | Russian Journal of Earth Sciences, Vol. 15, ES3001 8p. | Mantle | Plume |
| Abstract: The regularities of the global intraplate volcanism of the Earth are explained by the mantle plumes originating at the heads and margins of two piles of dense material of the hot and relatively heavy D?? layer at the base of the mantle. Due to thermal blanket effect under a supercontinent the overheated region with ascending flows arises in the mantle. These flows distort the D?? layer and produce the thermochemical piles in the lowermost mantle under the supercontinent. It is supposed that the pile under Africa originated at the time of existence of Pangea, while the pile under the Pacific Ocean originated at the time of existence of Rodinia. As Africa succeeds to Pangea, the pile under Africa exists until now. But it stays unclear why the pile under the Pacific Ocean exists up to now despite supercontinent Rodinia has been broken-up a long time ago. The numerical models of thermochemical convection in the whole mantle with spherical geometry which include the heavy D?? layer allow to clear up effects of supercontinents and lithospheric plates on deformations of the D?? layer by mantle flows and formation of the thermochemical piles. |
DC201501-1740 2014 | True North Gems Inc. | Mine development progress report for the Aappaluttoq ruby project. | True North Gems Inc., Dec. 16, 1p. | Europe, Greenland | News item - press release |
DC201502-1741 2015 | True North Gems Inc. | True North to update Aappaluttoq pre-feasibility study. | True North Gems Inc., Jan. 6, 1p. | Europe, Greenland | News item - press release |
DC201503-1742 2015 | True North Gems Inc. | True North Gems provides Aappaluttoq construction update. | True North Gems Inc., Jan. 29, 2p. | Europe, Greenland | News item - press release |
DC201504-1743 2015 | True North Gems Inc. | True North Gems announces positive update to Aappaluttoq pre-feasibility study. | Ture North Gems Inc., Feb 25, 3p. | Europe, Greenland | News item - press release |
DC201504-1744 2015 | True North Gems Inc. | True North appoints Raymond Simpson to Board of Directors. | Ture North Gems Inc., Feb. 26, 1p. | Europe, Greenland | News item - press release |
DC201504-1745 2015 | True North Gems Inc. | True North Gems files pre-feasibility study and provides construction update on the Aappaluttoq project. | True North Gems Inc., Mar. 18, 2p. | Europe, Greenland | News item - press release |
DC201509-1746 2015 | True North Gems Inc. | True North Gems secures US$ 4 million in financing for the Aappaluttoq ruby project in SW Greenland. | True North Gems Inc., Aug. 26, 2p. | Europe, Greenland | News item - press release |
DC201511-2412 2015 | True North Gems Inc. | True North Gems pours concrete for the Aappaluttoq ruby and pink sapphire process plant. | True North Gems Inc., Sept. 30, 1p. | Europe, Greenland | News item - press release |
DC201512-2462 2015 | True North Gems Inc. | True North Gems completes procurement & shipping of gemstone processing plant. Aappaluttoq | Truth North Gems Inc., Nov. 5, 2p. | Europe, Greenland | News item - press release |
DC201501-1747 2014 | Tsodilo Resources Limited | Conceptual model for BK16. | Tsodilo Resources Limited, Dec. 15, 2p. | Africa, Botswana | News item - press release |
DC201505-1752 2015 | Tsodilo Resources Limited | Purchases mobile DMS treatment plant. | Tsodillo Resources Ltd., Apr. 8, 2p. | Africa, Botswana | News item - press release |
DC201506-1748 2015 | Tsodilo Resources Limited | Completes diamond core drilling program on BK16. | Tsodilo Resources Limited, May 6, 3p. | Africa, Botswana | News item - press release |
DC201507-1753 2015 | Tsodilo Resources Limited | Takes possession of previously recovered diamonds from BK16. | Tsodilo Resources Ltd., June 22, 2p. Photos on website | Africa, Botswana | News item - press release |
DC201508-1749 2015 | Tsodilo Resources Limited | Exploration geological model and exploration target for BK16. | Tsodilo Resources Limited, July 15, 5p. | Africa, Botswana | News item - press release |
DC201509-1750 2015 | Tsodilo Resources Limited | Announces non-brokered private placement ( project Gcwihaba Resources ). | Tsodilo Resources Limited, Aug. 5, 1p. | Africa, Botswana | News item - press release |
DC201509-1751 2015 | Tsodilo Resources Limited | Tsodilo Resources closes private placement financing. | Tsodilo Resources Limited, Aug. 10, 1p. | Africa, Botswana | News item - press release |
DC201510-2369 2015 | Tsodilo Resources Limited | Tsodilo Resources Limited is pleased to announce the appointment of Mark Scowcroft to its Board of Directors as a non-executive director, effective September 1, 2015. | Tsodilo Resources Limited, Sept. 1, 1p. | Africa, Botswana | News item - press release |
DC201512-2463 2015 | Tsodilo Resources Limited | Tsodilo share private placement accepted by TSX-V. | Tsodilo Resources Ltd., Oct. 29, 1p. | Africa, Botswana | News item - press release |
DS201502-0117 2015 | Tsuno, K., Dasgupta, R. | Fe Ni Cu C S phase relations at high pressures and temperatures - the role of sulfur in carbon storage and diamond stability at mid to deep upper mantle. | Earth and Planetary Science Letters, Vol. 412, pp. 132-142. | Mantle | Carbon |
DS201512-1980 2015 | Turner, D., Rivard, B., Groat, L. | Visible to shortwave infrared reflectance spectroscopy of rare earth element minerals. | Symposium on critical and strategic materials, British Columbia Geological Survey Paper 2015-3, held Nov. 13-14, pp. 219-230. | Technology | Rare earths |
DM201506-2477 2015 | Turner, R. | Timberlites and crutons: the early days of the Great Canadian diamond rush. Precis of his talk to 25th. Anniversary celebration of MDRU. | The Northern Miner, May 11-17, p. 5 | Canada | News item - history |
DM201511-2205 2015 | Turner, R. | The great Canadian diamond rush. | Vancouver Kimberlite Cluster, Oct. 28, 1/4p. Abstract | Canada | News item - history |
DS201507-0338 2015 | Upadhyay, D., Kooijman, E., Singh, A.K., Mezger, K., Berndt, J. | The basement of the Deccan Traps and its Madagascar connection: constraints from xenoliths. | Journal of Geology, Vol. 123, pp. 295-310. | Africa, Madagascar | Xenoliths |
DS201504-0226 2015 | Valentine, G.A., Graettinger, A.H, Macorps, E., Ross, P-S., White, J.D.L., Dohring, E., Sonder, I. | Experiments with vertically and laterally migrating subsurface explosions with applications to the geology of phreatomagmatic and hydrothermal explosion craters and diatremes. | Bulletin of Volcanology, Vol. 77, 15p. | Technology | Diatremes, kimberlites |
DS201504-0227 2014 | Valentine, G.A., Graettinger, A.H, Sonder, I. | Explosion depths for phreatomagmatic eruptions. | Geophysical Research Letters, Vol. 41, pp. 3045-51. | Technology | Magmatism - phreatomagmatic |
DS201509-0434 2015 | Valley, J.W., Reinhard, D.A., Cavosie, A.J., Ushikubo, T., Lawrence, D.F., Larson, D.J., Kelly, T.F., Snoeyenbos, D.R., Strickland, A. | Nano- and micro-geochronology in Hadean and Archean zircons by atom-probe tomography and SIMS: new tools for old minerals. | American Mineralogist, Vol. 100, pp. 1355-1377. | Australia | Geochronology |
| Abstract: Atom-probe tomography (APT) and secondary ion mass spectrometry (SIMS) provide complementary in situ element and isotope data in minerals such as zircon. SIMS measures isotope ratios and trace elements from 1–20 ?m spots with excellent accuracy and precision. APT identifies mass/charge and three-dimensional position of individual atoms (±0.3 nm) in 100 nm-scale samples, volumes up to one million times smaller than SIMS. APT data provide unique information for understanding element and isotope distribution; crystallization and thermal history; and mechanisms of mineral reaction and exchange. This atomistic view enables evaluation of the fidelity of geochemical data for zircon because it provides new understanding of radiation damage, and can test for intracrystalline element mobility. Nano-geochronology is one application of APT in which Pb isotope ratios from sub-micrometer domains of zircon provide model ages of crystallization and identify later magmatic and metamorphic reheating. |
DS201502-0118 2015 | van der Meijde, M., Fadel, I., Ditmar, P., Hamayun, M. | Uncertainties in crustal thickness models for dat a sparse environments: a review for South America and Africa. | Journal of Geodynamics, Vol. 84, 1, pp. 1-18. | South America, Africa | Geophysics - seismics |
DS201503-0181 2015 | Van Kranendonk, M.J., Smithies, R.H., Griffin, W.L., Huston, D.L., Hickman, A.H., Champion, D.C., Anhaeusser, C.R., Pirajno, F. | Making it thick: a volcanic plateau origin of Paleoarchean continental lithosphere of the Pilbara and Kaapvaal cratons. | Geological Society of London Special Publication: Continent formation through time., No. 389, pp. 83-111. | Australia, Africa, South Africa | Geotectonics |
DS201502-0119 2014 | Van Leeuwen, T. | The enigmatic Sundaland diamonds - a review. | Proceedings of Sundaland Resources 2014 MGEI Annual Convention held Nov. 17-18, Palembang, South Sumatra, Indonesia, 28p. Available pdf | Indonesia, Kalimantan, Myanmar | Sundaland diamonds |
DS201512-1981 2015 | Van Wychen, W., Copland, L., Burgess, D.O., Gray, L., Schaffer, N., Fisher, T. | Glacier velocities and dynamic discharge from the ice masses of Baffin Island and Bylot Island, Nunavut, Canada. | Canadian Journal of Earth Sciences, Vol. 52, 11, pp. 980-989. | Canada, Nunavut, Baffin Island | Geomorphology |
| Abstract: Speckle tracking of ALOS PALSAR fine beam data from 2007-2011 are used to determine the surface motion of major ice masses on Baffin Island and Bylot Island in the southern Canadian Arctic Archipelago. Glacier velocities are low overall, with peaks of ?100 m a?1 and means of ?20-60 m a?1 common along the main trunk of many outlet glaciers. Peak velocities on Penny and Bylot Island ice caps tend to occur near the mid-sections of their primary outlet glaciers, while the fastest velocities on all other glaciers usually occur near their termini due to relatively large accumulation areas draining through narrow outlets. Estimates of ice thickness at the fronts of tidewater-terminating glaciers are combined with the velocity measurements to determine a regional dynamic discharge rate of between ?17 Mt a?1 and ?108 Mt a?1, with a mid-point estimate of ?55 Mt a?1, revising downward previous approximations. These velocities can be used as inputs for glacier flow models, and provide a baseline dataset against which future changes in ice dynamics can be detected. |
DS201510-1811 2015 | Vandenberg, J.A., Herrell, M., Faithful, J.W., Snow, A.M., Lacrampe, J., Bieber, C., Dayyani, S., Chisholm, V. | Multiple modeling approach for the aquatic effects assessment of a proposed northern diamond mine development. Gahcho Kue | Mine Water and the Environment, in press available, 19p. | Canada, Northwest Territories | Deposit - Gahcho Kue |
| Abstract: Eight water models were used to assess potential aquatic environmental effects of the proposed Gahcho Kué diamond mine on groundwater and surface water flow and quality in the Northwest Territories, Canada. This sequence of models was required to cover different spatial and temporal domains, as well as specific physico-chemical processes that could not be simulated by a single model. Where their domains overlapped, the models were interlinked. Feedback mechanisms amongst models were addressed through iterative simulations of linked models. The models were used to test and refine mitigation plans, and in the development of aquatic component monitoring programs. Key findings generated by each model are presented here as testable hypotheses that can be evaluated after the mine is operational. This paper therefore offers a record of assumptions and predictions that can be used as a basis for post-validation. |
DS201510-1812 2015 | Vasconcelos, L. | Geoethics - Africa needs to be respected and heard. | Journal of African Earth Sciences, Vol. 111, p. 287. 1p. | Africa | CSR - ethics |
| Abstract: The Journal of African Earth Sciences (Vol. 111, 2015, page 287) has published a "Short Note" entitled "Geoethics: Africa must be respected and heard!" by Lopo Vasconcelos, Jesus Martinez-Frias and Aberra Mogessie, raising an important issue: the need to include ethical issues in the educational systems of Africa. Reference is made to a project aiming at "providing the entire African continent with a roadmap to face the target of geoscience education within a wide scope and a multidisciplinary approach" GEO-ERA (GEOscience Education Roadmap for Africa) promoted and coordinated by the IUGS-Commission on Geoscience Education, Training and Technology Transfer (IUGS-COGE) and the Geological Society of Africa (GSAf). Considering that Education and Ethics must go along together, GSAf and IAGETH (International Association for Geoethics) signed in 2013, after the 24th Colloquium of African Geology, CAG24 (Addis Ababa) a Memorandum of Understanding in order to accomplish this and other goals. |
DS201512-1982 2015 | Verplanck, P.L., Farmer, G.L., Mariano, A.N. | Nd and Sr isotopic composition of rare earth element mineralized carbonatites. | Symposium on critical and strategic materials, British Columbia Geological Survey Paper 2015-3, held Nov. 13-14, pp. 65-74. | Global | Carbonatite |
| Abstract: For nearly 50 years, carbonatites have been the primary sources of niobium and rare earth elements (REEs), particularly the light REEs including La, Ce, Pr, and Nd. In addition, carbonatites may be enriched in other critical elements and have the potential to be future sources. Currently, only fi ve of the more than 500 known carbonatites in the world are being mined for REEs: Bayan Obo (Inner Mongolia, China); Maoniuping (Sichuan, China); Dalucao (or Daluxiang, Sichuan, China); and Mountain Pass (California, USA), and the carbonatite-derived laterite at Mount Weld (Australia). To achieve ore-grade REE enrichment, initial carbonatitic magmas require an adequate endowment of REEs and need to evolve in ways for these elements to concentrate in REE-bearing mineral phases. Radiogenic isotope studies of carbonatites clearly point to a mantle origin, but a wide range in isotopic compositions has led to contrasting views about the specifi c mantle reservoir(s) that sourced carbonatites. In this study we use the neodymium and strontium isotopic compositions of a suite of mineralized carbonatites to establish the nature of the source magmas. We examine samples that span a wide range in age (~23 Ma to 1385 Ma), Nd concentrations (3720 to 32,900 ppm), and Sr concentrations (2290 to 167,900 ppm). Our Nd and Sr isotopic data include multiple samples from Mountain Pass (USA; ?Nd i = -3.1 to -5.4, Sri = 0.70512 to 0.70594), Elk Creek (USA; ~?Nd i = 1.7, Sri = 0.7035), and Maoniuping (China; ?Nd i = -4.1 and -4.2, Sri = 0.70627 and 0.70645), and one sample each from Bear Lodge (USA; ?Nd i = 0.1, Sri = 0.70441), Kangankunde (Malawi; ?Nd i = 3.3, Sri = 0.70310), Adiounedj (Mali; ?Nd i = -0.1, Sri = 0.70558), and Mushgai Khudag (Mongolia; ?Nd i = -1.3, Sri = 0.70636). Isotopic data from two producing carbonatite REE deposits (Mountain Pass and Maoniuping) have broadly similar isotopic compositions (?Nd i = -3.1 to -5.4 and Sri = 0.7051 to 0.7065), and these compositions point to a carbonated source in the lithospheric mantle. Mineralized but unmined carbonatites have higher Nd initial isotopic compositions (?Nd i = -1.3 to 3.3) and a wider range in Sr isotopic compositions (Sri = 0.70310 to 0.70637), but these data are consistent with a lithospheric mantle reservoir. |
DS201512-1983 2015 | Vershovskii, A.K., Dmitriev, A.K. | Pecularities of optical and ODMR spectra of nitrogen-vacancy color centers in diamond crystals. | Journal of Physics Condensed Matter, Vol. 541, 1, pp. 12090-12094. | Technology | Diamond crystallography |
| Abstract: The optical and ODMR spectra of nitrogen vacancy (NV) centers in diamond were investigated as applied to the development of micro-scale diamond magnetometer sensor. It is shown that the NV0 center (unlike the NV? center) has an absorption line in the UV range. The inversion of the zero phonon line of the NV? center was observed and explained. ODMR signals in high magnetic fields (as compared with inner fields in the crystal) as well as in weak fields also were investigated. We propose the solution to the problem of the magnetometer sensitivity reduction at low magnetic field, that is of interest for quantum magnetometry applications. Peculiarities of optical and ODMR Spectra of Nitrogen-Vacancy Color Centers in Diamond Crystals. |
DS201507-0339 2015 | Vladkar, S.G. | Mineralogy and geochemistry of fenitized nephelinites of the Amba Dongar complex, Gujarat. | Journal of the Geological Society of India, Vol. 85, 1, pp. 87-97. | India | Nephelinite |
DS201502-0120 2015 | Vladykin, N. | K-alkaline rocks and lamproites of Tomtor Massif. | Economic Geology Research Institute 2015, Vol. 17,, # 2937, 1p. Abstract | Russia | Lamproite |
DS201502-0121 2015 | Vladykin, N. | Maldzhangarsky rare metal carbonatite massif in the NE part of the Anabar shield. | Economic Geology Research Institute 2015, Vol. 17,, # 2891, 1p. Abstract | Russia | Carbonatite |
DS201504-0228 2015 | Vynntska, L., Bunge, H-P. | Restoring past mantle convection structure through fluid dynamic inverse theory: regularization through surface velocity boundary conditions. | International Journal of Geomathematics, Vol. 6, 1, pp. 83-100. | Mantle | Geodynamics |
DS201509-0435 2015 | Wainwright, A.N., Luguet, A., Fonsec, R.O.C., Pearson, D.G. | Investigating metasomatic effects on the 187Os isotopic signature: a case study on the micrometric base metal sulphides in metasomatised peridotite from the Letlhakane kimberlite, (Botswana). | Lithos, Vol. 232, pp. 35-48. | Africa, Botswana | Deposit - Letlhakane |
| Abstract: The peridotite xenoliths of the Letlhakane kimberlite (Botswana), which intrude the Proterozoic Magondi Belt on the western margin of the Zimbabwe craton, represent highly depleted melting residues. These residues suffered subsequent variable metasomatic overprinting, evidenced by cryptic trace element enrichments in the spinel peridotites to modal addition of phlogopite, clinopyroxene and spinel within the garnet peridotites. In order to assess the robustness of the Re–Os chronometer in such highly metasomatised peridotites, detailed investigations of base metal sulphide (BMS) petrography and single-BMS grain 187Os/188Os analyses have been undertaken in three representative peridotites. |
DM201511-2206 2015 | Wall Street Journal | Rio Tinto pares output of less-sparkling niche commodities. Diamonds and salt. Republicofmining.com | Wall Street Journal, Oct. 16, 1/2p. | Global | News item - Rio Tinto |
DM201511-2207 2015 | Wall Street Journal | Inside De Beers's hunt for Africa's elusive diamonds. Kalahari desert | Wall Street Journal, Oct. 23, 1p. | Africa, Botswana | News item - De Beers |
DM201512-2323 2015 | Wall Street Journal | Richards bared new details of the company's financial troubles. Koidu mine. | Wall Street Journal , Nov. 11, 2p. | Africa, Sierra Leone | News item - BSG Resources |
DS201510-1813 2015 | Walter, M.J., Thomson, A.R., Wang, W., Lord, O.T., Ross, J., McMahon, S.C., Baron, M.A., Melekhova, E., Kleppe, A K., Kohn, S.C. | The stability of hydrous silicates in Earth's lower mantle: experimental constraints from the systems MgO-SiO2-H2O and MgO-Al2O3-SiO2-H2). | Chemical Geology, Vol. 418, pp. 16-29. | Mantle | Experimental petrology |
| Abstract: We performed laser-heated diamond anvil cell experiments on bulk compositions in the systems MgO-SiO2-H2O (MSH) and MgO-Al2O3-SiO2-H2O (MASH) that constrain the stability of hydrous phases in Earth’s lower mantle. Phase identification by synchrotron powder diffraction reveals a consistent set of stability relations for the high-pressure, dense hydrous silicate phases D and H. In the MSH system phase D is stable to ~ 50 GPa, independent of temperature from ~ 1300 to 1700 K. Phase H becomes stable between 35 and 40 GPa, and the phase H out reaction occurs at ~ 55 GPa at 1600 K with a negative dT/dP slope of ~ -75 K/GPa. Between ~ 30 and 50 GPa dehydration melting occurs at ~ 1800K with a flat dT/dP slope. A cusp along the solidus at ~ 50 GPa corresponds with the intersection of the subsolidus phase H out reaction, and the dT/dP melting slope steepens to ~ 15 K/GPa up to ~ 85 GPa. |
DS201508-0379 2015 | Wang, K-L., Prikhodko, V., O'Reilly, S.Y., Griffin, W.L., Pearson, N.J., Kovach, V., Lizuka, Y., Chien, Y-H. | Ancient mantle lithosphere beneath the Khanka Massif in Russian Far-East: in situ Re-Os evidence. | Terra Nova, Vol. 27, 4, pp. 277-284. | Russia | Geochronology |
DS201512-1984 2015 | Wang, K-L., Prikhodo, V., O'Reilly, S.Y., Griffin, W.L., Pearson, N.J., Kovach, V., Iizuka, Y., Chien, Y-H. | Ancient mantle lithosphere beneath the Khanka massif in the Russian Far East: in situ Re-Os evidence. | Terra Nova, Vol. 27, 4, pp. 277-284. | Russia | Geochronology |
| Abstract: The Os-isotope compositions of sulphides in mantle xenoliths hosted by Late Miocene alkali basalts from the Sviyaginsky volcano, Russian Far East, reveal the presence of Archaean-Proterozoic subcontinental lithospheric mantle beneath the Khanka massif. Their TMA and TRD model ages reveal similar peaks at 1.1 and 0.8 Ga suggesting later thermotectonic events in the subcontinental lithospheric mantle, whereas TRD model ages range back to 2.8 ± 0.5 (2?) Ga. The events recognized in the subcontinental lithospheric mantle are consistent with those recorded in the crust of the Khanka massif. The sulphide Os-isotope data show that the subcontinental lithospheric mantle beneath the Khanka massif had formed at least by the Mesoproterozoic, and was subsequently metasomatized by juvenile crustal-growth events related to the evolution of the Altaids. The Khanka massif is further proposed to have tectonic affinity to the Siberia Craton and should originate from it accordingly. |
DS201512-1985 2015 | Wang, S-J., Teng, F-Z., Rudnick, R.L., Li, S-G. | Magnesium isotope evidence for a recycled origin of cratonic eclogites. | Geology, Vol. 43, 12, pp. 1071-1074. | Africa, Sierra Leone | Deposit - Koidu |
| Abstract: The Mg isotopic compositions of garnet and clinopyroxene mineral separates and whole rocks from 21 xenolithic eclogites (11 low-MgO eclogites and 10 high-MgO eclogites) from the Koidu kimberlite complex, erupted within the Archean Man Shield, Sierra Leone, West Africa, provide new evidence bearing on the origin of cratonic eclogites. Garnet and clinopyroxene in both low-MgO and high-MgO eclogites generally record equilibrium inter-mineral Mg isotope partitioning, with ?26Mg varying from -2.15‰ to -0.46‰ in garnets and from -0.49‰ to +0.35‰ in clinopyroxenes. Bulk ?26Mg values (-1.38‰ to +0.05‰), constructed from garnet and clinopyroxene data, are similar to results from rock powders (-1.60‰ to +0.17‰), suggesting that kimberlite infiltration has had negligible influence on the Mg isotopic compositions of the xenoliths. The ?26Mg values of low-MgO eclogites (-0.80‰ to +0.05‰) exceed the range of mantle peridotite xenoliths (-0.25‰ ± 0.04‰), consistent with the eclogite’s derivation from recycled altered oceanic crust. Similarly variable ?26Mg values in high-MgO eclogites (-0.95‰ to -0.13‰), together with their high MgO and low FeO contents, suggest that high-MgO eclogites were produced by Mg-Fe exchange between partially molten low-MgO eclogites and surrounding peridotites. Our study shows that cratonic xenolithic eclogites preserve a record of Mg isotopic compositions produced by low-pressure, surficial isotope fractionations. The recycling of oceanic crust therefore increases the Mg isotope heterogeneity of the mantle. |
DS201503-0178 2015 | Wang, T., Song, X., Xia, H.H. | Earth's core has a core. | Nature Geoscience, Feb. 10, 3p. Online | Earth, Mantle | Geophysics - seismic |
DS201510-1814 2015 | Wang, W. | Preference in formation of H3 over H4 and its implication in gem diamond identification. | GSA Annual Meeting, Paper 300-7, 1p. Abstract only Booth | Technology | HPHT |
| Abstract: Defects H3 and H4 are common in natural, HPHT treated, and artificially irradiated fancy colored diamonds. Understanding of their formation is important for color origin determination in gem labs. However, there are still substantial challenges. Davies (1972) studied the effect of different forms of nitrogen on the annealing of radiation damage, and found A/B = H3/H4. However, Collins (1982, 2001) pointed out that some natural type Ia diamonds could have H3 absorption but even when they contain substantial amounts of nitrogen in the B-form, the H4 absorption is negligible. In this study, based on investigation of a group of 39 (0.12 - 7.03 ct) natural green - yellow diamonds, vacancy source for formation H3 and H4 is identified and preference formation of H3 over H4 is discussed. Nitrogen concentrations of these diamonds fell in a range of 32- 496 ppm, with average 0.67 for B/(B+A). So, significant amount of B-form nitrogen exist. No irradiation feature of H1a, H1b, H1c, or 595 nm absorption was detected. Absorption spectra in the UV-Vis region were dominated by defects N3 and H3. Strong emission bands from H3 were observed, and its fluorescence substantially contributed to the body colors of green - yellow. As an outstanding feature, absorption or emission of defect H4 is entirely absent, despite significant concentrations of B-form nitrogen. Strong plastic deformation is a common feature in all samples. Green fluorescence from defect H3 clearly followed dislocation by showing up to 3 sets of parallel lines, instead of following growth zonation. These sharp lines are continuous throughout the whole stones. Strong dislocations indicated that these diamonds were originlly in brown color after the plastic deformation and thus with significant concentrations of vacancy clusters. Annealed in the earth’s mantle over a long geological history, single vacancies released from vacancy clusters could combine with the A-form nitrogen to form H3. Strong preference in forming H3 over H4 could be related to the unknown disaggregation process of vacancy clusters and the annealing in the earth’s mantle over long geological time. Absence of H4 in this type of diamonds could be considered as a useful indication of natural color origin. |
DS201504-0229 2015 | Wang, Y., Santosh, M., Lou, Z., Hao, J. | Large igneous provinces linked to supercontinent assembly. | Journal of Geodynamics, Vol. 85, pp. 1-10. | Global | Geotectonics |
DS201502-0122 2015 | Warnsloh, J.M. | TriAngle: a microsoft excel spreadsheet template for the generation of triangular plots. | Neues Jahrbuch fur Mineralogie, Vl. 192, 1, pp. 101-105. | Technology | Plots |
DS201506-0298 2015 | Watt, G. | Coloured gemstone App. | mayerandwatt.com, App free | Technology | Coloured gemstones |
DS201509-0437 2015 | Weiss, Y., McNeill, J., Pearson, D.G., Ottley, C.J. | Highly saline fluids from a subducting slab as the source for fluid-rich diamonds. | Nature, Vol. 524, pp. 339-342. | Mantle | Subduction |
| Abstract: The infiltration of fluids into continental lithospheric mantle is a key mechanism for controlling abrupt changes in the chemical and physical properties of the lithospheric root1, 2, as well as diamond formation3, yet the origin and composition of the fluids involved are still poorly constrained. Such fluids are trapped within diamonds when they form4, 5, 6, 7 and so diamonds provide a unique means of directly characterizing the fluids that percolate through the deep continental lithospheric mantle. Here we show a clear chemical evolutionary trend, identifying saline fluids as parental to silicic and carbonatitic deep mantle melts, in diamonds from the Northwest Territories, Canada. Fluid–rock interaction along with in situ melting cause compositional transitions, as the saline fluids traverse mixed peridotite–eclogite lithosphere. Moreover, the chemistry of the parental saline fluids—especially their strontium isotopic compositions—and the timing of host diamond formation suggest that a subducting Mesozoic plate under western North America is the source of the fluids. Our results imply a strong association between subduction, mantle metasomatism and fluid-rich diamond formation, emphasizing the importance of subduction-derived fluids in affecting the composition of the deep lithospheric mantle. |
DS201512-1986 2015 | Weiss, Y., Pearson, D.G., Mcneill, J., Nowell, G.M., Ottley, C.J. | Salty fluids, subducted slabs and NWT diamonds. | 43rd Annual Yellowknife Geoscience Forum Abstracts, abstract p. 108. | Canada, Northwest Territories | Diamond genesis |
| Abstract: Diamonds from the Ekati and Diavik mines have provided a wealth of information on diamond forming processes beneath the Slave craton. Fluid-rich “fibrous” diamonds trap some of the fluid from which the diamond is growing and hence provide a unique means to characterize directly the fluids that percolate through the deep continental lithospheric mantle. On a world-wide basis, Ekatic and Diavik fluid-rich diamonds trap an anomalously high proportion of fuids that are “salty” or high saline in composition, with high Na and Cl contents. The origin of these “salty” fluids has been something of a mystery. Here we show the first clear chemical evolutionary trend identifying saline fluids as parental to silicic and carbonatitic deep mantle melts, in diamonds from the Northwest Territories, Canada. Fluid-rock interaction along with in-situ melting cause compositional transitions, as the saline fluids traverse mixed peridotite-eclogite lithosphere. Moreover, the chemistry of the parental saline fluids - especially their Sr isotopic compositions - and the timing of host diamond formation suggest a subducting Mesozoic plate under western North America to be the source of the fluids. Our results imply a strong association between subduction, mantle metasomatism and fluid-rich diamond formation, emphasizing the importance of subduction-derived fluids in impacting the composition of the deep lithospheric mantle |
DS201512-1987 2015 | Wells, D. | Diavik mine environment update, | 43rd Annual Yellowknife Geoscience Forum Abstracts, abstract p. 108. | Canada, Northwest Territories | Deposit - Diavik |
| Abstract: Since 2003 Diavik Diamond Mines Inc. has been mining diamonds from kimberlite pipes located below the waters of Lac de Gras. Monitoring and mitigating our impact on the local environment has been a core value at Diavik since our initial discovery. The mine was designed, and is operated, in a manner to reduce our overall environmental footprint and ultimately allow for a safe and efficient closure. A core team of scientists and technicians are responsible for monitoring the air, water, wildlife and regulatory compliance at the mine site. This presentation will focus on the work of this dedicated team. |
DS201508-0380 2015 | Whitchurch, A. | Tectonics: continental complexity. | Nature Geoscience, Vol. 8, p. 502. | Mantle | Lithosphere |
DS201512-1988 2015 | White, D., Bezzola, M., Hrkac, C., Vivian, G. | Kennady North property: 2015 field season update. | 43rd Annual Yellowknife Geoscience Forum Abstracts, abstract p. 109. | Canada, Northwest Territories | Deposit - Kennady North |
| Abstract: The Kennady North Property, wholly owned by Kennady Diamonds Inc. (KDI) is located 300 km northeast of Yellowknife adjacent to the DeBeers/Mountain Province Gahcho Kué mine site. Exploration on the property dates back to the early 90’s, during which time several kimberlites were discovered. Since 2012 Kennady Diamonds has completed a number of geophysical, hand and RC till sampling and diamond drill programs. In 2015, KDI completed a large diameter reverse circulation drill program to bulk sample the southern lobe of the Kelvin kimberlite. Following the RC program, diamond drilling and ground geophysical surveys continued in the Kelvin-Faraday Corridor (KFC) and at various exploration targets on the property including the MZ Dyke and Doyle Sill. The field season started in January with the completion of the Kelvin camp and the construction of the RC drill icepad on Kelvin Lake. The pad and a seasonal spur road off the Gahcho Kue seasonal road were completed to coincide with the opening of the Tibbit-Contwoyto winter road and facilitated the mobilization of two large diameter RC rigs operated by Midnight Sun Drilling Inc. to the property. A total of 446 tonnes of the Kelvin kimberlite were obtained via RC drilling between February 19 and April 2. The bulk sample was processed via DMS at the Saskatchewan Research Council in Saskatoon. One diamond drill commenced drilling prior to the RC program and two other drills commenced on the heels of the RC program. A total of 31,000 meters of NQ and HQ core have been drilled during 2015 to the end of October. Drilling at Kelvin has focused on geotechnical and related environmental baseline work as well as further delineation of the pipe-like body with the aim of generating a NI43-101 compliant resource in early 2016. Diamond drilling at the Faraday group of kimberlites delineated the Faraday 1 and Faraday 2 kimberlites. These pipe-like bodies share a similar pipe-like structure and internal geology to the Kelvin kimberlite. Aurora conducted 8848 stations of ground gravity and 521.32 line-kilometers of OhmmapperTM capacitively coupled resistivity in the KFC, MZ dyke, and Doyle Sill during March and April. A 87 line-kilometer bubble seismic survey over the Kelvin, Faraday and MZ complexes was conducted in September. Kennady Diamond Inc. is very encouraged by the exploration results to date and anticipates a successful and exciting 2016. |
DS201502-0123 2014 | White, L., Graham, I., Armstrong, R., Hall, R. | Tracing the source of Borneo's Cempaka deposit. | American Geophysical Union, December - Fall meeting in San Francisco, abstract | Asia, Kalimantan | Deposit - Cempaka |
DS201508-0381 2015 | Whitehead, J.A., Behn, M.D. | The continental drift convection cell. Wilson Cycle) | Geophysical Research Letters, Vol. 42, 11, June 16, pp. 4301-4308. | Global | Convection |
DS201512-1989 2015 | Williams-Jones, A.E. | The hydrothermal mobility of the rare earth elements. | Symposium on critical and strategic materials, British Columbia Geological Survey Paper 2015-3, held Nov. 13-14, pp. 119-124. | Technology | Rare earths |
DS201512-1990 2015 | Williams-Jones, A.E., Vasyukova, O. | Fluoride-silicate melt immisicibility and the formation of the pegmatite-hosted Strange Lake REE deposit, Quebec-Labrador. | Symposium on critical and strategic materials, British Columbia Geological Survey Paper 2015-3, held Nov. 13-14, pp. 91-96. | Canada, Quebec, Labrador | Rare earths |
DS201512-1991 2015 | Williams-Jones, A.E., Wollenberg, R., Bodeving, S. | Hydrothermal fractionaction of the rare earth elements and the genesis of the Lofdal REE deposit, Namibia. | Symposium on critical and strategic materials, British Columbia Geological Survey Paper 2015-3, held Nov. 13-14, pp. 125-130. | Africa, Namibia | Rare earths |
DS201512-1992 2015 | Winterburn, P. | Exploration geochemistry: principles and practices for the strategic commodities Nb, Ta, Zr, and rare earth elements. | Symposium on critical and strategic materials, British Columbia Geological Survey Paper 2015-3, held Nov. 13-14, pp. 193-198. | Technology | Rare earths |
| Abstract: Geochemical exploration for Nb, Ta, Zr and rare earth element (REE) mineralization associated with carbonatite, pegmatite, and peralkaline intrusions presents unique challenges and opportunities. The challenges are mainly due to the tendency of these elements, as High Field Strength Elements (HFSE), to be relatively immobile in surface environments in addition to commonly forming minerals that are resistant to weathering. In addition, many of the host minerals are resistant to routine exploration geochemistry digestions, which are typically aimed at dissolving soluble oxides or extracting more labile ionic forms (Reimann et al., 2014). Opportunities arise because host rocks typically represent relatively rare end products of the magmatic processes that generate peralkaline magmas including, at the far end of the spectrum, carbonatites. Hence host rocks are relatively easy to identify geochemically and commonly defi ne classic lithological zoning (e.g., Modreski et al., 1995). In addition, many of the minerals that contain these elements are resistant to weathering, mechanically durable, have relatively high densities, and have the have the potential to form heavy mineral concentrates when released by weathering. This is particularly so for Zr, Nb, and Ta, which form primary minerals such as tantalite (Ta Nb), pyrochlore (Nb), coltan (Ta Nb), columbianite (Ta Nb), dysanalite-perovskite (Nb) and zircon (Zr). In contrast, the REE are mobile in the weathering environment and commonly re-locate from primary carbonate and phosphate minerals (e.g., synchysite, monazite, xenotime, bastnäsite, allanite) to secondary phosphate minerals such as churchite (Lottermoser, 1990) and gorceixite (Mariano, 1989). |
DS201509-0438 2015 | Witherly, K. | Backgrounder on award for HT SQUID development ( Cathy Foley and Keith Leslie) Clunies Ross award for inovation. | ken @condorconsult.com, 2p. Aug. 15 | | Geophysics - SQUID |
DS201511-1887 2015 | Wolff, F.C. | Does price dispersion increase with quality? Evidence from the online diamond market ( using 160,000 dat a statistics) from www.diamond-infos.com) | Applied Economics, Vol. 47, 11, pp. 5996-6009. | Global | Diamond market ( online) |
| Abstract: This article empirically investigates the relationship between price dispersion and price level. Searches seem more valuable for products of high quality, but buyers may have little incentive to search since such products are less frequently purchased. The extent of price dispersion is examined using a sample of around 160 000 diamonds offered for sale online. Estimates from a two-stage econometric strategy show that price dispersion increases significantly with quality. An explanation is that buyers of high-quality gemstones pay little attention to the price of these diamonds and even more so if they perceive high prices as signals of quality and rarity of the diamonds they intend to purchase. |
DS201507-0340 2015 | Womp-int.com | New Culli nan facility will improve diamond recovery, cut costs. | Womp-int.com, 1p. | Africa, South Africa | Deposit - Cullinan |
DS201506-0299 2015 | World Diamond Magazine | Diamond grading standards. | World Diamond Conference Nov. 23, Perth, Free subscription email communications @worlddiamondmark .org | Technology | Diamond grading |
DS201511-1888 2002 | Wortman, J. | GMP Junior diamond companies ….. Overview not much information | GMP Group, March 15, 54p. Available pdf | Global | Microdiamonds - responses |
DS201502-0124 2014 | Wu, F.Y., Xu, Y., Zhu, X., Zhang, G.W. | Thinning and destruction of the cratonic lithosphere: a global perspective. | Science China Earth Sciences, Vol. 57, no. 12, pp. 2878-2890. | China, Global | Plume, subduction |
DS201512-1993 2015 | Wu, N.W., Schmitt, A.K., Pappalardo, L. | U-Th baddeleyite geochronology and its significance to date the emplacement of silica undersaturated magmas. | American Mineralogist, Vol. 100, pp. 2082-2090. | Mantle | Magmatism |
| Abstract: Baddeleyite is a frequently found accessory mineral in silica undersaturated lavas. Because it is typically enriched in uranium, while having low initial lead, baddeleyite has long been a prime target for U-Pb geochronology of mafic rocks. The difficulties in retrieving small baddeleyite grains from volcanic samples and the lack of a detailed understanding of baddeleyite occurrence, however, have limited baddeleyite chronology largely to coarse-grained mafic intrusive rocks. Here, the development of U-Th in situ baddeleyite analysis using secondary ionization mass spectrometry (SIMS) is presented together with an assessment of baddeleyite occurrence in Quaternary silica-undersaturated lavas from Campi Flegrei (Naples, Italy). Samples studied comprise the pre- and post Campanian Ignimbrite (ca. 40 ka) lava domes of Cuma and Punta Marmolite, and Astroni and Accademia, respectively. The in situ sample preparation required initial identification of baddeleyite crystals from sawed and polished rock billets using scanning electron microscope (SEM) backscatter imaging and energy-dispersive X-ray analysis. U-Th baddeleyite isochron ages for intra-caldera Astroni and Accademia lava domes are 5.01+2.61?2.55 ka (MSWD = 2.0; n = 17) and 4.36+1.13?1.12 ka (MSWD = 2.9; n = 24), respectively. The ages for Punta Marmolite (62.4+3.9?3.8 ka; MSWD = 1.2; n = 11) and Cuma (45.9+3.6?3.5 ka; MSWD = 2.2; n = 11) predate the Campanian Ignimbrite. Rapid baddeleyite crystallization at the time of emplacement is supported by petrologic observations that >50% of the baddeleyite crystals documented in this study occur either in vesicles or in vesicle-rich regions of the host lavas whose textures developed over timescales of a few years to a few decades based on microlite crystal size distribution (CSD) analysis. Radiometric U-Th baddeleyite ages are mostly in agreement with previously determined K-Ar eruption ages, except for the Punta Marmolite lava dome whose U-Th baddeleyite age predates the K-Ar age by ca. 15 ka. Baddeleyite thus records eruptive emplacement with little evidence for significant pre-eruptive crystal residence, and has potential as an eruption chronometer for Quaternary silica-undersaturated volcanic rocks. |
DS201506-0300 2015 | Wu, Xiao, Xu, Santosh, Li, Huang, Hou. | Geochronology and geochemistry of felsic xenoliths in lamprophyre dikes from the southeastern margin of the North Chin a Craton: implications for the interleaving of the Dabie Sulu orogenic crust. | International Geology Review, Vol. 57, 9-10, pp. 1305-1325. | China | Dabie Sulu |
DS201507-0341 2015 | Wyman, D.A., Hollings, P., Conceicao, R.V. | Geochemistry and radiogenic isotope characteristics of xenoliths in Archean Diamondiferous lamprophyres: implications for the Superior Province cratonic keel. | Lithos, Vol. 233, pp. 111-130. | Canada, Ontario | Lamprophyre |
DS201508-0382 2015 | Xie, Y., Li, Y., Hou, Z., Cooke, D.R., Danyushevsky, L., Dominy, S.C., Yin, S. | A model for carbonatite hosted REE mineralization - the Mianning-Dechang REE belt, western Sichuan Province, China. | Ore Geology Reviews, Vol. 70, pp. 595-612. | China | Carbonatite |
DS201504-0231 2015 | Xiong, Q., Griffin, W.L., Zheng, J-P., O'Reilly, S.Y., Pearson, N.J. | Episodic refertilization and metasomatism of Archean mantle: evidence from an orogenic peridotite in North Qaidam ( NE Tibet) China. | Contributions to Mineralogy and Petrology, Vol. 169, 24p. | China, Tibet | Peridotite |
DS201510-1815 2015 | 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. | China | UHP |
| 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. |
DS201512-1994 2015 | Yang, J., Dilek, Y., Robinson, P.T. | Diamond and recycled mantle: a new perspectve - introduction of IGCP 649 project. Ophiolites | Acta Geologica Sinica, Vol. 89, 3, pp. 1036-1038. | Mantle | Diamond genesis |
DS201502-0126 2014 | Yang, J., Meng, F., Xu, X., Robinson, P.T., Dilek, Y., Makeyev, A.B., Wirth, R., Wiedenbeck, M., Cliff, J. | Diamonds, native elements and metal alloys from chromitites of the Ray-Iz ophiolite of the Polar Urals. | Gondwana Research, Vol. 27, 2, pp. 459-485. | Russia, Urals | Chromitite |
DS201510-1816 2015 | Yang, J-S., Wirth, R., Xu, X., Tian, Y., Huang, Z., Robinson, P.T., Dilek, Y. | Formation of ophiolite hosted diamonds by deep subduction of oceanic lithosphere: evidence from mineral inclusions. | GSA Annual Meeting, Paper 81-2, 1p. Abstract only | Mantle | Mineral inclusions |
| Abstract: In recent years we have confirmed the existence of ophiolite-hosted diamonds on Earth, which occur in mantle peridotites and podiform chromitites of many ophiolites. These diamonds differ significantly from most kimberlite varieties, particularly in their inclusions. The typical inclusions in the diamonds are Mn-rich phases, i.e., NiMnCo alloy, native Mn, MnO, galaxite, Mn olivine and Mn garnet. Ca-silicate perovskite, a typical lower mantle mineral, was identified as mineral inclusions in diamond. One occurs as a 60-nanometer, euhedral grain associated with NiMnCo alloy and graphite, while another one occurs as a 50-nanometer grain within a large inclusion containing both NiMnCo alloy and Nd-Se-Cu-S phase. By EDS the perovskite has Ca 48.3%, Si 37.7% and Mn 14.1% with oxygen. TEM diffraction data show that the inclusion has d-spacings and angles between adjacent lattice planes are consistent to the Ca-silicate perovskite with an orthorhombic structure. The only known source of such light carbon is organic material in surface sediments and the best known sources of abundant manganese are Fe-Mn-rich sediments and Mn nodules, both of which are common on the seafloor. Many parts of the modern seafloor are also covered by sediments with a continental provenance. Phases such as SiO2 and Al2O3 are not expected in mantle peridotites and must have been introduced from shallow levels. We propose that subduction of oceanic lithosphere carries C, Mn, Si, Al and REE to the transition zone or lower mantle where the material is mixed with highly reduced material, perhaps derived from greater depths. Crystallization of diamond from a C-rich fluid encapsulates the observed inclusions. The diamonds and associated minerals are incorporated into chromite grains during chromite crystallization at depth of mantle transition zone, and are carried to shallower levels by mantle convection. Accumulation of chromite grains produces podiform chromitites containing a range of exotic minerals. However, the presence of diamonds and other UHP minerals in ophiolitic peridotites indicates that such phases can persist far outside their normal stability fields. |
DS201512-1995 2015 | Yang, X. | OH solubility in olivine in the peridotote-COH system under reducing conditions and implications for water storage and hydrous melting in the reducing upper mantle. | Earth and Planetary Science Letters, Vol. 432, pp. 199-209. | Mantle | Melting |
| Abstract: Experimental studies of OH solubility in peridotite minerals are of crucial importance for understanding some key geochemical, geophysical and geodynamical properties of the upper mantle. In reducing depths of the upper mantle, C-O-H fluids are dominated by CH4 and H2O. However, available experimental H-annealing of olivine concerning water storage capacity in the reducing upper mantle has been exclusively carried out by equilibrating olivine with H2O only. In this study, OH solubility in olivine has been investigated by annealing natural olivine crystals under peridotite-bearing and CH4-H2O-present conditions with piston cylinder and multi-anvil apparatus. Experiments were performed at 1-7 GPa and 1100-1350?°C and with oxygen fugacity controlled by Fe-FeO buffer, and OH solubilities were measured from polarized infrared spectra. The olivines show no change in chemical composition during the experiments. The infrared spectra of all the annealed olivines show OH bands in the range 3650-3000 cm?1, at both high (>3450 cm?1) and low (<3450 cm?1) frequency, and the bands at ?3400-3300 cm?1 are greatly enhanced above ?3 GPa and 1300?°C. The determined H2O solubility is ?90-385 ppm for the olivine coexisting with H2O (1-7 GPa and 1100?°C), and is ?40-380 ppm for the olivine coexisting with CH4-H2O (1-7 GPa and 1100-1350?°C). When CH4 is present in the equilibrium fluid, the H2O solubility is reduced by a factor of ?2.3 under otherwise identical conditions, indicating a strong effect of CH4 on the partitioning of water between olivine and coexisting fluid. The storage capacity of water in the reducing upper mantle is, modeled with the measured solubility of olivine and available partition coefficients of water between coexisting minerals, up to ?2 orders of magnitude lower than some previous estimates. Considering the temperature along the geotherm in the reducing oceanic upper mantle, the required H2O concentration to trigger hydrous melting is 250 and 535 ppm at ?100 and 210 km depth, respectively, and is even larger at greater depths. These values exceed the typical H2O abundance (?100±50 ppm?100±50 ppm) in the upper mantle, suggesting that pervasive hydrous melting at reducing depths of the oceanic upper mantle is not likely. Similar arguments may also be casted for the reducing deep upper mantle in the continental regions. |
DS201512-1996 2015 | Yang, X., Williams, M. | Landforms and processes in arid and semi-arid environments. | Catena, Vol. 134, pp. 4-13. | Africa, South Africa, Australia | Geomorphology |
DS201511-1889 2015 | Yap, C.M., Tarum, A., Xiao, S., Misra, D.S. | MPCVD growth of 13 C-enriched diamond single crystals with nitrogen addition. | Diamond and Related Materials, in press available, 29p. | Technology | Synthetics - nitrogen |
| Abstract: This study describes the growth of 13C-enriched (100)-oriented diamond single crystals by the MPCVD (microwave plasma chemical vapour deposition) process. All crystals are at least 6 × 6 mm2 in area and 0.5-1.0 mm in thickness. The samples with nominal 13C percentages (R = [13C] / [13C + 12C]) of 0.011 (natural abundance), 0.10, 0.21, 0.24 and 0.34 were obtained by controlling the flow of the carbon-13 and carbon-12 methane feed gases. To obtain thicker and near-colourless quality 13C-enriched diamond, 190 ppm of nitrogen was added into the gas mixture. The shift towards lower frequency in the Raman peak positions and decrease in the thermal conductivities of the near-colourless crystals with increasing 13C percentages are similar to previous studies of isotopically-controlled diamond grown with no nitrogen additive. The images of the structural defects associated with 13C-enrichment obtained by spatially-resolved X-ray rocking curve measurement show distinct patterned structures that runs parallel to the < 100 > direction. Moreover, the broadening in the line width of the nuclear magnetic resonance (NMR) peak from sp313C correlates with increasing R. We also expand the study by injecting 500 ppm of nitrogen. Higher nitrogen concentration leads to the formation of brown crystals. The brown crystals show far greater 13C NMR peak intensity than the near-colourless. This suggests that paramagnetic nitrogen impurities in the brown crystals hasten the spin-lattice relaxation time of the 13C nuclear spin that resulted in higher intensity. The isotopic splitting observed for the localized vibrational mode of the NVH0 defect in brown crystals is attributed to the co-existence of both the 13C (3114.2 cm? 1) and 12C (3123.5 cm? 1). Unlike the isotopic splitting observed for NVH0 defect, the peak position of the Ns+ defect shifts towards lower frequency as R increases. Not only have we demonstrate the growth of bigger isotopically-controlled diamond single crystals, the results shown here have provided a framework to further investigate the interplay between 13C atoms and nitrogen impurity. |
DS201509-0439 2015 | Yelisseyev, A., Khrenov, A., Afanasiev, V., Pustovarov, V., Gromilov, S., Panchenko, A., Pokhilenko, N., Litasov, K. | Luminescence of natural carbon nanomaterial: impact diamonds from the Popigai crater. | Diamond and Related Materials, Vol. 58, pp. 69-77. | Russia | Deposit - Popigai |
| Abstract: Impact diamonds (IDs) from the Popigai crater are aggregates of nanoparticulate graphite and cubic and hexagonal diamonds. IDs demonstrate broad-band emissions at 3.05, 2.8, 2.3 and 2.0 eV, which are associated with structural defects and are similar to those in detonation ultra-dispersed diamonds and CVD diamond films. A doublet with components at 1.7856 and 1.7892 eV in some ID samples is related to R1,2 lines of Cr3 + ions in corundum inclusions. The presence of N3, H3, NV0 and NV? vibronic systems in some of the ID samples shows that (i) there is nitrogen impurity and (ii) samples underwent high temperature annealing that promoted vacancies and nitrogen diffusion and defect aggregation. The luminescence decay fits with a sum of two exponential components: lifetime of the fast one is in the 5 to 9 ns range. Parameters of the traps responsible for broad thermoluminescence peaks at 148, 180, 276 and 383 K were estimated. |
DS201511-1890 2015 | Yip, C.K., Thompson, K.S. | Diavik Diamond Mines Inc. NI 43-101 Technical Report. | Diavik Diamond Mines Inc., March 18, 128p. Available pdf | Canada, Northwest Territories | Microdiamonds - responses |
DS201502-0127 2015 | You, J. | Geoscientists aim to magnify specialized web searching. GeoLink could become search hub for the geoscience community. | Sciencemag.org, Vol. 347, 6217 Jan. 2, p. 11 ( 1p) | Technology | GeoLink |
DS201510-1817 2015 | Yu, J., LU, R. | Color shift and pleochroism in Tanzanite. | GSA Annual Meeting, Paper 300-6, 1p. Abstract only Booth | Technology | Tanzanite |
| Abstract: Colored stones are increasingly accepted in China gem market in recent years. Tanzanite owing to its unique violetish blue color is readily recognized and attracts broad attention. Natural, unheated blue tanzanite is known for its trichroic colors in bluish violet, violetish blue, yellow-green. Much lesser known, tanzanite also exhibits metachromatism, a color shift, when illuminated by cold and warm light sources. However, limited existing reports and studies have been mostly descriptive on general gem deposit and basic gemological characteristics. Very little data exit on color shift and pleochroism distinctive to tanzanite. Quantitative analysis on these color characteristics under heating virtually is lacking, even though over 95% tanzanite materials on gem market are reported to have been heated to improve its appearance. This study presents direct observational results on color shift with controlled warm (`3200K) and cold (`6500K) light sources under polarization and known crystallographic orientations. Further quantitative analysis have been performed by polarized spectroscopic measurement on trichroic to dichroic color conversion in tanzanite samples from a set of heating experiments between 650 and 900 °C. Optimal heating temperature for these experiments was determined by thermal analysis (TG-DTA), which showed that tanzanite became unstable above 960 °C. Our optical observation and quantitative results revealed that a yellow-green coloration along the c-crystallographic direction converted and virtually merged into existing blue coloration after heating. Consequently, tanzanite converted from natural, unheated trichroic to heated dichroic. |
DC201511-2373 2015 | Yu, Y., Liu, K.H., Reed, C.A., Moidaki, M., Mickus, K., Atekwana, E.A., Gao, S.S. | Canterra closes first tranche of private placement and extends financing. | Canterra Minerals Corporation, Oct. 20, 1p. | Canada, Northwest Territories | News item - press release |
DS201512-1997 2015 | Yu, Y., Liu, K.H., Reed, C.A., Moidaki, M., Mickus, K., Atekwana, E.A., Gao, S.S. | A joint receiver function and gravity study of crustal structure beneath the incipient Okavango Rift, Botswana. | Geophysical Research Letters, Vol. 42, 20, pp. 8398-8405. | Africa, Botswana | Geophysics - gravity |
| Abstract: Rifting incorporates the fundamental processes concerning the breakup of continental lithosphere and plays a significant role in the formation and evolution of sedimentary basins. In order to decipher the characteristics of rifting at its earliest stage, we conduct the first teleseismic crustal study of one of the world's youngest continental rifts, the Okavango Rift Zone (ORZ), where the magma has not yet breached the surface. Results from receiver function stacking and gravity modeling indicate that the crust/mantle boundary beneath the ORZ is uplifted by 4-5 km, and the initiation of the ORZ is closely related to lithospheric stretching. Possible decompression melting of the subcrustal lithosphere occurs beneath the ORZ, as evidenced by a relatively low upper mantle density based on the gravity modeling. |
DS201511-1891 2015 | Yuan, H. | Secular changes in Archean crust formation recorded in western Australia. | Nature Geoscience, Vol. 8, 10, pp. 808-813. | Australia | Geophysics - seismics, subduction |
| Abstract: The formation mechanisms for early Archaean continental crust are controversial. Continental crust may have accumulated via horizontal accretion in modern-style subduction zones or via vertical accretion above upper mantle upwelling zones. However, the characteristics of the continental crust changes at the transition between the Archaean and Proterozoic eons, suggesting that continental crust did not form in subduction zones until at least the late Archaean. Here I use seismic receiver function data to analyse the bulk properties of continental crust in Western Australia, which formed and stabilized over a billion years in the Archaean. I find that the bulk seismic properties of the crust cluster spatially, with similar clusters confined within the boundaries of tectonic terranes. I use local Archaean crustal growth models to show that both plume and subduction processes may have had a role in creating crust throughout the Archaean. A correlation between crustal age and the bulk seismic properties of the crust reveals a trend: from about 3.5?Gyr ago (Ga) to the end of the Archaean, the crust gradually thickened and simultaneously became more evolved in composition. I propose that this trend reflects the transition between crust dominantly formed above mantle plumes, to crust formed in subduction zones-a transition that may reflect secular cooling of Earth’s mantl |
DS201509-0440 2015 | Yuryeva, O.P., Rakhmanova, M.I., Nadolinny, V.A., Zedgenizov, D.A., Shatsky, V.S., Kagi, H., Komarovskikh, A.Yu. | The characteristic photoluminescence and EPR features of superdeep diamonds ( Sao Luis, Brazil). | Physics and Chemistry of Minerals, In press available 16p. | South America, Brazil, Mato Grosso | Deposit - Juina area |
| Abstract: Photoluminescence (PL) spectroscopy and electron paramagnetic resonance (EPR) were used for the first time to characterize properties of superdeep diamonds from the São-Luis alluvial deposits (Brazil). The infrared measurements showed the low nitrogen content (>50 of 87 diamonds from this locality were nitrogen free and belonged to type IIa) and simultaneously the extremely high level of nitrogen aggregation (pure type IaB being predominant), which indicates that diamonds under study might have formed under high pressure and temperature conditions. In most cases, PL features excited at various wavelengths (313, 473, and 532 nm) were indicative of different growth and post-growth processes during which PL centers could be formed via interaction between vacancies and nitrogen atoms. The overall presence of the 490.7 nm, H3, and H4 centers in the luminescence spectra attests to strong plastic deformations in these diamonds. The neutral vacancy known as the GR1 center has probably occurred in a number of crystals due to radiation damage in the post-growth period. The 558.5 nm PL center is found to be one of the most common defects in type IIa samples which is accompanied by the EPR center with g-factor of 2.00285. The 536 and 576 nm vibronic systems totally dominated the PL spectra of superdeep diamonds, while none of "normal" diamonds from the Mir pipe (Yakutia) with similar nitrogen characteristics showed the latter three PL centers. |
DS201511-1892 2015 | Yuryeva, O.P., Rakhmanova, M.I., Nadolinny, V.A., Zedgenizov, D.A., Shatsky, V.S., Kagi, H., Komarovskikh, A.Yu. | The characteristic photoluminescence and EPR features of superdeep diamonds ( Sao-Luis, Brazil). | Physics and chemistry of Minerals, Vol. 42, 9, pp. 707-722. | South America, Brazil | Sao-Luis alluvials |
| Abstract: Photoluminescence (PL) spectroscopy and electron paramagnetic resonance (EPR) were used for the first time to characterize properties of superdeep diamonds from the São-Luis alluvial deposits (Brazil). The infrared measurements showed the low nitrogen content (>50 of 87 diamonds from this locality were nitrogen free and belonged to type IIa) and simultaneously the extremely high level of nitrogen aggregation (pure type IaB being predominant), which indicates that diamonds under study might have formed under high pressure and temperature conditions. In most cases, PL features excited at various wavelengths (313, 473, and 532 nm) were indicative of different growth and post-growth processes during which PL centers could be formed via interaction between vacancies and nitrogen atoms. The overall presence of the 490.7 nm, H3, and H4 centers in the luminescence spectra attests to strong plastic deformations in these diamonds. The neutral vacancy known as the GR1 center has probably occurred in a number of crystals due to radiation damage in the post-growth period. The 558.5 nm PL center is found to be one of the most common defects in type IIa samples which is accompanied by the EPR center with g-factor of 2.00285. The 536 and 576 nm vibronic systems totally dominated the PL spectra of superdeep diamonds, while none of "normal" diamonds from the Mir pipe (Yakutia) with similar nitrogen characteristics showed the latter three PL centers. |
DS201505-0239 2015 | Zahirovic, S., Muller, R.D., Seton, M., Flament, N. | Tectonic speed limits from plate kinematic reconstructions. | Earth and Planetary Science Letters, Vol. 418, pp. 40-52. | Global | Plate Tectonics |
DS201506-0301 2015 | Zedgenizov, D.A., Pokhilenko, N.P., Griffin, W.L. | Carbonate- silicate composition of diamond forming media of fibrous diamonds from Snap Lake area, Canada. | Doklady Earth Sciences, Vol. 461, 1, pp. 297-300. | Canada, Northwest Territories | Micro-inclusions |
DS201502-0128 2015 | Zedgenizov, D.A., Shatsky, V.S., Panin, A.V., Evtushenko, O.V., Ragozin, A.L., Kagi, H. | Evidence for phase transitions in mineral inclusions in superdeep diamonds of the Sao Luiz deposit, Brazil. | Russian Geology and Geophysics, Vol. 56, 1, pp. 296-305. | South America, Brazil | Deposit - Sao Luiz |
DS201510-1818 2015 | Zhao, D., Zhang, Y., Essene, E.J., Wang, R. | Electron probe microanalysis and microscopy: principles and applications in characterization of mineral inclusions in chromite from diamond deposit. | Ore Geology Reviews, Vol. 65, pt. 4, pp. 733-748. | China | Deposit - Wafangdian |
| Abstract: Electron probe microanalysis and microscopy is a widely used modern analytical technique primarily for quantifying chemical compositions of solid materials and for mapping or imaging elemental distributions or surface morphology of samples at micrometer or nanometer-scale. This technique uses an electromagnetic lens-focused electron beam, generated from an electron gun, to bombard a sample. When the electron beam interacts with the sample, signals such as secondary electron, backscattered electron and characteristic X-ray are generated from the interaction volume. These signals are then examined by detectors to acquire chemical and imaging information of the sample. A unique part of an electron probe is that it is equipped with multiple WDS spectrometers of X-ray and each spectrometer with multiple diffracting crystals in order to analyze multiple elements simultaneously. An electron probe is capable of analyzing almost all elements (from Be to U) with a spatial resolution at or below micrometer scale and a detection limit down to a few ppm. Mineral inclusions in chromite from the Wafangdian kimberlite, Liaoning Province, China were used to demonstrate the applications of electron probe microanalysis and microscopy technique in characterizing minerals associated with ore deposits, specifically, in this paper, minerals associated with diamond deposit. Chemical analysis and SE and BSE imaging show that mineral inclusions in chromite include anhydrous silicates, hydrous silicates, carbonates, and sulfides, occurring as discrete or single mineral inclusions or composite multiple mineral inclusions. The chromite–olivine pair poses a serious problem in analysis of Cr in olivine using electron probe. Secondary fluorescence of Cr in chromite by Fe in olivine drastically increases the apparent Cr2O3 content of an olivine inclusion in a chromite. From the chemical compositions obtained using electron probe, formation temperatures and pressures of chromite and its mineral inclusions calculated using applicable geothermobarometers are from 46 kbar and 980 °C to 53 kbar and 1130 °C, which are within the stability field of diamond, thus Cr-rich chromite is a useful indication mineral for exploration of kimberlite and diamond deposit. A composite inclusion in chromite composed of silicate and carbonate minerals has a bulk composition of 33.2 wt.% SiO2, 2.5 wt.% Al2O3, 22.0 wt.% MgO, 7.5 wt.% CaO, 2.5 wt.% BaO, 0.8 wt.% K2O, 25.5 wt.% CO2, and 0.8 wt.% H2O, similar to the chemical composition of the Wafangdian kimberlite, suggesting that it is trapped kimberlitic magma. |
DS201511-1893 2015 | Zhao, X., Shi, G., Zhang, J. | Review of lithospheric diamonds and their mineral inclusions. | Advances in Earth Science *** Chinese ( eng. Abstract only), Vol. 30, 3, pp. 310-322. | Mantle | Diamond inclusions |
| Abstract: Diamonds and their mineral inclusions are valuable for studying the genesis of diamonds, the characteristics and processes of ancient lithospheric mantle and deeper mantle. This has been paid lots of attentions by geologists both at home and abroad. Most diamonds come from lithospheric mantle. According to their formation preceded, accompanied or followed crystallization of their host diamonds, mineral inclusions in diamonds are divided into three groups: protogenetic, syngenetic and epigenetic. To determine which group the mineral inclusions belong to is very important because it is vital for understanding the data’s meaning. According to the type of mantle source rocks, mineral inclusions in diamonds are usually divided into peridotitic (or ultramafic) suite and eclogitic suite. The mineral species of each suite are described and mineralogical characteristics of most common inclusions in diamonds, such as olivine, clinopyroxene, orthopyroxene, garnet, chromite and sulfide are reviewed in detail. In this paper, the main research fields and findings of diamonds and their inclusions were described: ?getting knowledge of mineralogical and petrologic characteristics of diamond source areas, characteristics of mantle fluids and mantle dynamics processes by studying the major element and trace element compositions of mineral inclusions; ?discussing deep carbon cycle by studying carbon isotopic composition of diamonds; ?determining forming temperature and pressure of diamonds by using appropriate assemblages of mineral inclusions or single mineral inclusion as geothermobarometry, by using the abundance and aggregation of nitrogen impurities in diamonds and by measuring the residual stress that an inclusion remains under within a diamond ; ?estimating the crystallization ages of diamonds by using the aggregation of nitrogen impurities in diamonds and by determine the radiometric ages of syngenetic mineral inclusions in diamonds. Genetic model of craton lithospheric diamonds and their mineral inclusion were also introduced. In the end, the research progress on diamonds and their inclusions in China and the gap between domestic and international research are discussed. |
DS201501-0034 2015 | Zheng, J.P., Lee, C.T.A., Lu, J.G., Zhao, J.H., Wu, Y.B., Xia, B., Li, X.Y., Zhang, J.F., Liu, Y.S. | Refertilization driven destabilization of subcontinental mantle and the importance of initial lithospheric thickness for the fate of continents. | Earth and Planetary Science Letters, Vol. 409, pp. 225-229. | China | Peridotite |
DS201511-1894 2014 | 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. | Technology | Diamond morphology |
DS201511-1895 2014 | 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. | China | Synthetics |
DS201506-0302 2015 | Zhu, H., Yang, J., Robinson, P.T., Zhu, Y., Zhu, F., Zhao, X., Liu, Z., Zhang, W., Xu, W. | The discovery of diamonds in chromitites of the Hegenshan ophiolite, Inner Mongolia, China. | Acta Geologica Sinica, Vol. 89, 2, pp. 341-350. | China, Mongolia | Chromitite |
DS201502-0129 2014 | Zhu, L-F., Wang, X-f., Pan, X. | Moving KML geometry elements within Google Earth. | Computers & Geosciences, Vol. 72, pp. 176-183. | Technology | Not specific to diamonds |
DS201502-0130 2015 | Zhu, X-k., Sun, J., Pan, C. | Sm-Nd isotopic constraints on rare earth mineralization in the Bayan Obo ore deposit, Inner Mongolia, China. | Ore Geology Reviews, Vol. 64, pp. 543-553. | China | Deposit - Bayan Obo |
DS201501-0035 2014 | Zhu, Y., Cuma, M., Kinakin, Y., Zhdanov, M.S. | Joint inversion of airborne gravity gradiometry and magnetic dat a from the Lac de Gras region of the Northwest Territories. | SEG Annual Meeting Denver, 5p. Extended abstract | Canada, Northwest Territories | Deposit - Lac de Gras region |
DM201504-1377 2015 | Zimnisky, P. | Global diamond output to rise in 2015. | London Mining Journal, Special publication for PDAC pp. 17,18,20,21. | Global | News item - overview |
DM201508-1378 2015 | Zimnisky, P. | Rough diamonds down 3.4% over last 6 months according to new rough diamond price index. | Zimnisky.com, July 9, 2p. | Global | News item - prices |
DM201512-2324 2015 | Zimnisky, P. | The state of the diamond industry going into year-end 2015. | Mining.com, Nov. 5, 6p. | Global | News item - markets |
DM201512-2325 2015 | Zimnisky, P. | Zimnisky global rough diamond price index (.ZGRDIA) | paulzimnisky.com, Nov. 21, 2p. | Global | News item - prices |
DS201503-0182 2015 | Zimnisky, P. | Global rough diamond production estimated to hot over 135 m carats in 2015. | Diamond analytics, paul @paulzimnisky.com, Feb. 6, 14p. | | Production figures |
DC201509-1755 2015 | Zimtu Capital Corporation | Commences exploration program at the Munn Lake property. | Zimtu Capital Corporation, Aug. 25, 3p. | Canada, Northwest Territories | News item - press release |
DS201512-1998 2015 | Zorzi, L., Crawford, B., Ferguson, K. | Geological and structural interpretation of the Jay kimberlite host rocks. | 43rd Annual Yellowknife Geoscience Forum Abstracts, abstract p. 110. | Canada, Northwest Territories | Deposit - Jay |
| Abstract: The Ekati property is located above an eastward-dipping Archean suture in the central part of the Slave Structural Province of the Canadian Shield. The bedrock geology comprises supracrustal rocks (metamorphosed greywacke-mudstone turbidites) of the Neoarchean post-Yellowknife Supergroup that are intruded by syn to post-tectonic plutons, made up predominantly of granite, granodiorite, and tonalite. In addition, five mafic Proterozoic dyke swarms, ranging in age from ca. 2.23 to 1.27 Ga, intrude the area. The area is intersected by several mafic dykes, belonging mainly to the Malley, MacKenzie, and Lac de Gras dyke swarms. To date, approximately 150 kimberlites have been discovered at Ekati ranging in age from ca. 45 to 75 Ma, intruding Archean metasediments and granitoids of the Salve Craton. In addition to the 150 kimberlites on the Ekati property, more than 240 confirmed kimberlites have been discovered to date in the region known as the Lac de Gras kimberlite field. The kimberlites represent the only evidence for Phanerozoic igneous activity within the area. Kimberlites on the Ekati property show an apparent bias in the type of host rock they intrude and are commonly associated with faults or dykes of various orientations. The Jay kimberlite pipe is located in the southeastern quadrant of the Ekati property. It is approximately 25 km southeast of the Koala cluster (including Panda, Koala, Koala North and Beartooth kimberlite pipes), and 7 km north-northeast of the Misery Main pipe. Based on available geological data consisting of geophysical surveys, geological maps and borehole data, the Jay kimberlite pipe appears to be hosted within post- Yellowknife Supergroup granitic rocks, ranging from granite to granodiorite in composition. It is interpreted to be emplaced along a regional lithological contact between granitoid rocks and Yellowknife Supergroup metasedimentary rocks that were covered by a now eroded veneer of poorly consolidated muddy sediments. A diabase dyke trending approximately east-west occurs to the north of the Jay kimberlite pipe. Despite the available data, geological and structural settings of the Jay host rocks were still not well understood. This work represents the first comprehensive geological interpretation of the host rocks within the Jay pipe setting. The proposed interpretation will be based on the following: • a detailed review, compilation, and interpretation of previously published geological work in the area; • interpretation of high-resolution light detection and ranging (LiDAR) data; • high-resolution orthophotos and airborne geophysical data; • geological data from delineation and geotechnical boreholes drilled between 2005 and 2007, and the recent 2014 and 2015 drilling programs at the Jay pipe area. An implicit modelling approach has been used to develop a three dimensional geological and structural model of the Jay pipe host rocks based on the preliminary interpretation. Ongoing studies aim to decode the geological and structural controls on the Jay kimberlite emplacement, along with its relationship with the nearby Misery kimberlite cluster. |