Petrogenesis of Diamondiferous Eclogites from the Siberian Platform

这是一个科学家联盟对西伯利亚地台榴辉岩捕虏体进行的全面岩石学和地球化学研究，以确定西伯利亚榴辉岩捕虏体的组成和岩石学变化。利用电子探针和离子探针采集矿物的主要元素和微量元素数据。通过x射线荧光和仪器中子活化分析确定大块岩石组成，并收集矿物分离物和大块岩石的稳定同位素数据（C和O）（仅收集钻石的C同位素组成）。将在超纯矿物分离物和大块岩石上收集放射性成因同位素数据（Sr-Nd-Os），以评估这些样品的来源（例如，地壳或地幔）以及这些来源的模型年龄。来自比宿主岩石更古老的地幔捕虏体的钐钕等时线。最后，以五对石榴石斜辉石包裹体的形式出现了一个独特的机会，这些包裹体由钻石承载，而钻石又由Mir和Udachnaya管道中的榴辉岩模块承载。对这些成对包裹体进行微量元素和主元素研究，并将它们与寄主榴辉岩进行比较，对于我们理解榴辉岩和金刚石的形成以及寄主可能的交代作用至关重要。本研究将是首次对北半球太古宙地壳段榴辉岩捕虏体进行全面细致的研究。

9505930 Taylor This is a comprehensive petrographic and geochemical study of eclogite xenoliths from the Siberian platform using a consortium of scientists, to establish the compositional and petrographical variation of eclogite xenoliths from Siberia. Major- and trace-element data will be collected on minerals by electron and ion microprobe. Bulk-rock compositions determined by x-ray fluorescence and instrumental neutron-activation analysis, and stable isotopic data (C and O) will be collected on mineral separates and bulk rocks (C isotopic compositions only on diamond). Radiogenic isotopic data (Sr-Nd-Os) will be collected on ultra-pure mineral separates and bulk rocks to evaluate the sources from which these samples were derived (e.g., crustal or mantle) and the age of these sources by model ages. Samarium-Nd isochrons from mantle xenoliths that are older than their host rock. Finally, a unique opportunity has presented itself in the form of five pairs of garnet-clinopyroxene inclusions which are hosted by diamonds and which, in turn, are hosted by eclogite modules from the Mir and Udachnaya pipes. A trace- and major -element study involving these paired inclusions and comparing them to the host eclogites is paramount to our understanding of eclogite and diamond formation and possible later metasomatism of the host. This study will be the first comprehensive detailed study of eclogite xenoliths from a northern hemisphere Archean-aged crustal segment.