Composition and History of the Siberian Lithosphere: Major Element and Isotopic Evidence from Udachnaya Xenoliths

岩石学家和地球化学家之间的合作， 华盛顿卡内基研究所，华盛顿，华盛顿特区，和 地质和地球物理研究所，新西伯利亚苏联，将是 组织进行化学和同位素研究， 地幔岩捕虏体在西伯利亚金伯利岩中喷发。 苏联科学家将参与在 华盛顿，访问时间为2至8周。 发展 大陆板块起源的模型， 地幔根在很大程度上是基于 对南部非洲捕虏体的研究。 进一步 进步需要比较研究。 西伯利亚克拉通是最好的 因为捕虏体丰富， 苏联进行了收集和基础研究， investigators. 注意力将集中在低温， 形成橄榄岩和巨晶纯橄榄岩， 有时候会有钻石。 批量分析将允许比较 卡尔普瓦尔和西伯利亚的大草原。 Os、Sr、Nd的分析 而Pb将是西伯利亚地幔上首次进行的 岩石，并可能提供克拉通演化的记录， 在非洲捕虏体中被后白垩纪交代作用所掩盖。 深入了解钻石形成过程的时机和性质 地幔中Re和Os的位置和分布 矿物将被发现。

A collaboration between petrologists and geochemists of the Carnegie Institution of Washington, Washington, D.C., and the Institute of Geology and Geophysics, Novosibirsk USSR, will be organized to carry out chemical and isotopic research on xenoliths of mantle rocks erupted in Siberian kimberlites. Soviet scientists will participate in the research performed in Washington in visits ranging from 2 to 8 weeks. Development of models for the origin of continental cratons with their massive mantle roots has been based in considerable part on investigations of xenoliths from southern Africa. Further progress requires comparative study. The Siberian craton is best suited because xenoliths are abundant and because extensive collections and basic research have been carried out by Soviet investigators. Attention will be focused on low-temperature, craton-forming peridotites and on megacrystalline dunites that sometimes contain diamonds. Bulk analyses will permit comparison of the Karpvaal and Siberian cratons. Analyses for Os, Sr, Nd and Pb will be virtually the first performed on SIberian mantle rocks and may provide records of craton evolution that have been obscured in African xenoliths by post-Archaean metasomatism. Insights to the timing and nature of diamond-forming processes and to the location and distribution of Re and Os in mantle minerals will be sought.