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

将组织华盛顿特区卡内基研究所和苏联新西伯利亚地质和地球物理研究所的岩石学家和地球化学家合作，对西伯利亚金伯利岩中喷发的地幔岩石包体进行化学和同位素研究。苏联科学家将参加在华盛顿进行的研究，访问时间从2周到8周不等。大陆克拉通及其巨大的地幔根部起源模型的发展在很大程度上是基于对南部非洲捕虏体的调查。进一步的进展需要进行比较研究。西伯利亚克拉通是最合适的，因为捕虏体丰富，而且苏联调查人员进行了广泛的采集和基础研究。人们的注意力将集中在低温、克拉通形成的橄榄岩和有时含有钻石的巨晶金英岩上。大量分析将使卡普瓦尔和西伯利亚克拉通进行比较。在西伯利亚地幔岩石上，对Os、Sr、Nd和Pb的分析实际上将是第一次进行，并可能提供被后太古代交代作用掩盖在非洲捕虏体中的克拉通演化记录。将寻求对钻石形成过程的时间和性质以及Re和O在地幔矿物中的位置和分布的见解。

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.