Origin and Evolution of Archean Continental Lithosphere: A Pilot Study of the Sao Francisco Craton, Brazil

P.I.提出了一个由澳大利亚、巴西和美国地球科学家参与的跨国项目，对来自巴西圣弗朗西斯科克拉通的三代地幔岩石进行了初步的化学和多同位素研究。科马提岩可能是太古代地体之下地幔非常难熔的原因。主要的镁铁质侵入体通常涉及大陆岩石圈的演化，因此，为了解岩石圈在火成岩侵入时的组成和历史提供了线索。钾镁岩和金伯利岩代表富含不相容元素的小体积熔体，可能是岩石圈地幔。该项目涉及在巴西的实地工作和样本采集。澳大利亚墨尔本迪肯大学和莫纳什大学的S·埃斯佩兰卡博士将对样品进行岩相学和元素分析。然后，埃斯佩兰卡博士和P.I.在DTM进行的OS和ND同位素分析将被用来限制熔体的年龄和化学史，以及它们对地幔现在的组成和形成历史的意义。

The P.I.s propose a multi-national project involving Australian, Brazilian and U.S. geoscientists in a pilot chemical and multi-isotopic study of 3 generations of mantle derived rocks from the Sao Francisco Craton of Brazil. Komatiites may be responsible for the very refractory nature of mantle beneath Archean terrains. Major mafic intrusions often involve the continental lithosphere in their evolution and, hence, give clues as to the composition and history of the lithosphere at the time of igneous intrusion. Lamproites and kimberlites represent small volume melts of incompatible element rich, possibly lithospheric, mantle. The project involves field-work and sample collecting in Brazil. Petrographic and elemental analysis of the samples will be done by Dr. S. Esperanca of Deakin and Monash Universities in Melbourne, Australia. Os and Nd isotopic analysis at DTM by Dr. Esperanca and the P.I. will then be used to constrain the age and chemical history of the melts and their implications for the present composition and formation history of the mantle.