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The Sheahan Diamond Literature Reference Compilation - Scientific and Media Articles based on Major Keyword - Metamorphism
The Sheahan Diamond Literature Reference Compilation is compiled by Patricia Sheahan who publishes on a monthly basis a list of new scientific articles related to diamonds as well as media coverage and corporate announcements called the Sheahan Diamond Literature Service that is distributed as a free pdf to a list of followers. Pat has kindly agreed to allow her work to be made available as an online digital resource at Kaiser Research Online so that a broader community interested in diamonds and related geology can benefit. The references are for personal use information purposes only; when available a link is provided to an online location where the full article can be accessed or purchased directly. Reproduction of this compilation in part or in whole without permission from the Sheahan Diamond Literature Service is strictly prohibited. Return to Diamond Keyword Index
Sheahan Diamond Literature Reference Compilation - Scientific Articles by Author for all years
Each article reference in the SDLRC is tagged with one or more key words assigned by Pat Sheahan to highlight the main topics of the article. In an effort to make it easier for users to track down articles related to a specific topic, KRO has extracted these key words and developed a list of major key words presented in this Key Word Index to which individual key words used in the article reference have been assigned. In most of the individual Key Word Reports the references are in crhonological order, though in some such as Deposits the order is first by key word and then chronological. Only articles classified as "technical" (mainly scientific journal articles) and "media" (independent media articles) are included in the Key Word Index. References that were added in the most recent monthly update are highlighted in yellow.
Metamorphism refers to gradual change of a rock's chemistry or texture while remaining solid, mainly through a combination of pressure and heat over long time periods. These articles are scientific and deal with metamorphic rocks such as massifs which can contain diamonds, though not of commercial size and quality and the processes by which diamond source rocks such as eclogite and harzburgite form.
Ultra high pressure mineral assemblages of inclusions in garnets, zircon sand clinopyroxenes from Diamondiferous metamorphic rocks, northern Kazakhstan, USSR
Eos, Vol. 71, No. 43, October 23, p. 1707 Abstract
Decompressiong reactions and P=T conditions in high grade rocks, northernLabrador; P-T paths individual samples and implications for early Prot. tectonicevol
Journal of Petrology, Vol. 32, No. 1, February pp. 139-168
A new manifestation of micro-diamonds in metamorphic rocks as an evidence of the regional character of high-pressure metamorphism in KokchetavMassif.(in Russian)
Doklady Academy of Sciences Akademy Nauk SSSR, (Russian), Vol. 321, No. 1, pp. 189-193. # HB124
Langer, K., Robarick, E., Sobolev, N.V., Shatsky, V.S.
Single crystal spectra of garnets from Diamondiferous high pressure metamorphic rocks from Kazakhstan -indications for OH-,H2O, and FeTi chargetransfer.
European Journal of Mineralogy, Vol. 5, No. 6, Nov-Dec pp. 1091-1100.
Eclogite facies relics and a multistage breakdown in metabasites of the KTB pilot hole, northeast Bavaria: implications for the Variscan tectonometamorphic evol
Contributions to Mineralogy and Petrology, Vol. 112, pp. 261-278
Geochronology and isotopic character of ultrahigh pressure metamorphism with implications for collision of the Sino Korean and Yangtze Cratons, centralChina.
Buse, B., Schumacher, J.C., Sparks, R.S.J., Field, M.
Growth of bultfontenite and hydrogarnet in metasomatized basalt xenoliths in the B/K9 kimberlite, Damtshaa: insights into hydrothermal metamorphism pipe
Contributions to Mineralogy and Petrology, Vol. 160, 4, pp. 533-550.
Chen, Y.X., Zheng, Y-F., Chen, R-X., Zhang, S-B., Li, Q., Dai, M., Chen, L.
Metamorphic growth and recrystallization of zircons in extremely 18 O depleted rocks during eclogite facies metamorphism: evidence from U-Pb ages, trace elements and O-Hf isotopes.
Geochimica et Cosmochimica Acta, Vol. 75, 17, pp. 4877-4898.
Abstract: Clear evidence for subduction-induced metamorphism, and thus the operation of plate tectonics on the ancient Earth has been lacking. Theoretical calculations indicate that we may have been looking for something that cannot exist.
Geological Society of America Annual Meeting, Vol. 47, 7, p. 169. abstract
Russia
Metamorphic diamonds
Abstract: The metamorphic diamonds in the Kokchetav Massif show very diverse features in morphologies and grain sizes with other crystal characters, Raman spectra (FWHM, PL), cathodoluminescence spectra, C isotope, abundance, paragenesis with silicates and carbonates. The formations of these diamonds, however, seem to be related to H2O-fluid conditions.?Dolomite marble has the highest abundance in diamond. The diamond grew at two stages and 2nd stage growth was from H2O fluid. Grt-Bt gneiss is 2nd highest and the diamond shows several morphologies; however, no 2nd stage growth. In dolomite marble, diamond at 2nd stage has light carbon isotope, -17 to -27 whereas 1st stage diamond has -8 to -15. The light carbon of 2nd stage could be organic carbon in gneisses carried by H2O-fluid; dissolution of diamond in gneisses could have occurred. No 2nd stage growth in gneisses supports this idea. Carbon-bearing H2O fluid infiltration into dolomite marble caused the change of carbon solubility in fluid to precipitate abundant fine diamonds (10-20 mm), quickly. Recently discovered sp2 graphitic carbon inclusions in 2nd stage diamond (AGU2014F V13B-4771), which is a relic of metastable intermediate phase for diamond formation, suggest the diamond participation from H2O fluid. A minor amount of diamond (large-grained, ca. 150 µm at average) occurs in Grt-Cpx rock. Recently, we found the overgrowth of large-grained cubic diamond on small-grained one by multi-layered 2D Raman mappings (JpGU2014 No.02541). This indicates slow-growth in H2O-fluid having low oversaturation degree of carbon. UHP calcite marble contains a trace amount of small-grained diamond (no 2nd stage growth) only in diopside; titanite with coesite exsolution does not contain diamond. These suggest that very high H2O activity for titanite stability makes diamond unstable, and dissolution of diamond was possible. This is a similar relation with UHP dolomitic marble, which Arg-Fo and Arg-Ti-Chum were stable but diamond was unstable. In Tur-Fel-Qtz rock, diamond is included in new mineral "maruyamaite" (K-rich Tur); recent experiments show high-P and fluid-bearing conditions for maruyamaite. Summarizing these diverse features of the Kokchetav diamonds, those formation and their possible dissolutions have strong relationships with H2O-fluid conditions.
Annual Review of Earth and Planetary Sciences, Vol. 48, 30p. pdf
Mantle
subduction, metamorphism
Abstract: If we accept that a critical condition for plate tectonics is the creation and maintenance of a global network of narrow boundaries separating multiple plates, then to argue for plate tectonics during the Archean requires more than a local record of subduction. A case is made for plate tectonics back to the early Paleoproterozoic, when a cycle of breakup and collision led to formation of the supercontinent Columbia, and bimodal metamorphism is registered globally. Before this, less preserved crust and survivorship bias become greater concerns, and the geological record may yield only a lower limit on the emergence of plate tectonics. Higher mantle temperature in the Archean precluded or limited stable subduction, requiring a transition to plate tectonics from another tectonic mode. This transition is recorded by changes in geochemical proxies and interpreted based on numerical modeling. Improved understanding of the secular evolution of temperature and water in the mantle are key targets for future research. 1) Higher mantle temperature in the Archean precluded or limited stable subduction, requiring a transition to plate tectonics from another tectonic mode. 2) Plate tectonics can be demonstrated on Earth since the early Paleoproterozoic (since c. 2.2 Ga), but before the Proterozoic Earth's tectonic mode remains ambiguous. 3) The Mesoarchean to early Paleoproterozoic (3.2-2.3 Ga) represents a period of transition from an early tectonic mode (stagnant or sluggish lid) to plate tectonics. 4) The development of a global network of narrow boundaries separating multiple plates could have been kick-started by plume-induced subduction.
Abstract: Radiometric decay systems have played a crucial role in developing our understanding of the evolution of the early Earth. There are two main types of protocols for isotope measurements in geological materials: (i) bulk dissolution of rocks, or whole-grains and (ii) spatially resolved techniques (laser-ablation or ion-beam). These two approaches have sometimes led to results that are not easily reconciled for early Earth crustal rocks (? 3.6?Ga). While initial radiogenic isotope signatures (e.g. initial 176Hf/177Hf or initial 143Nd/144Nd) obtained from whole-rock protocols are significantly above chondritic values, indicative of extensive chemical differentiation of the mantle before 3.6?Ga, data from spatially resolved analysis of individual mineral growth domains point toward much less dramatic differentiation. This is indicated by the majority of data falling close to models of Earth's mantle that had not experienced major silicate melt removal into the crust. These data show chondritic or sub-chondritic signatures. Interpretations of whole rock isochrons are built on assumptions about the history and relationship of a number of different samples to each other. At the heart of these assumptions, the effects of secondary process-such as metasomatism-on isotopic compositions and consequently on the age and initial ratio of isochrons, are often considered negligible. In order to evaluate the possible effects of metasomatism and metamorphism on co-genetic igneous suites we modelled the impact of contamination by an external component on both the isochron slope (the apparent age) and the isochron intercept (the initial radiogenic isotope signature). A significant outcome is that the age significance of some of the modified isochron arrays remains to a large extent within uncertainty of the original crystallisation age of the igneous suite. In other words, the original age signature is preserved, but with lower precision. The intercept of the isochron, from which the initial isotope ratio is calculated, however is often significantly modified, which has consequences for the interpretation of these signatures. Our results provide an explanation for the discrepancy between whole-rock and spatially-resolved results observed in early Earth material. Lastly, our results, applied to studies of ancient crustal rocks, are interpreted as indicative of no significantly depleted mantle domains before 3.6?Ga, and no Hfsingle bondNd isotopes decoupling at that time.
