Os Isotopic Studies of Solid Earth Evolution

9804875Carlson本提案要求继续支持我们将Re-Os同位素系统应用于有关固体地球的地球化学演化问题的基于成就的更新。我们将集中于：1)圈定来自意大利、科罗拉多高原和非洲西南部的大洋中脊玄武岩和镁铁质-钾质火山的地幔成分(辉石岩、榴辉岩)的重要性。2)黑奴克拉通和澳大利亚西北部钻石中硫化物包裹体的Re-Os年龄测定。3)将克拉通地幔橄榄岩包体Re-Os系统学研究扩展到中国和西非。4)研究巴西米纳斯吉拉斯下地壳石榴石麻粒岩包体的Re-Os系统学，确定该区地壳形成的年代学。5)研究中国东部大别地体和苏鲁地体榴辉岩和橄榄岩的Re-Os系统，确定这些物质的火成岩形成时间，研究Re和Os在高级变质作用中的行为。6)用同位素稀释电感耦合等离子体质谱(ICPMS)测量了大部分Re-Os同位素变化样品的全岩PGE模式，提高了对PGE在火成岩分异过程中行为的认识。

9804875Carlson This proposal requests an Accomplishment Based Renewal for continued support of our application of the Re-Os isotope system to problems concerning the geochemical evolution of the solid Earth. We will focus on: 1) Delineation of the importance of mafic components (pyroxenites, eclogites) in the mantle sources of mid-ocean ridge basalts and mafic-potassic volcanism from Italy, the Colorado Plateau and southwestern Africa. 2) Re-Os age dating of sulfide inclusions in diamonds from the Slave craton and N.W. Australia. 3) Extend our studies of the Re-Os systematics of cratonic mantle peridotite xenoliths to China and west Africa. 4) Examine the Re-Os systematics of lower crustal garnet granulite xenoliths from Minas Gerais, Brazil to define the chronology of crust formation in this area. 5) Study the Re-Os system of the eclogitic and peridotitic rocks of the Dabie and Su-Lu terranes in eastern China to date the igneous formation of these materials and to examine the behavior of Re and Os during high-grade metamorphism. 6) Improve the understanding of the behavior of the platinum group elements (PGE's) during igneous differentiation by measuring whole rock PGE patterns by isotope dilution ICP-MS in most of the samples studied for Re-Os isotopic variation.