Geochemical Evolution of the Mantle

该更新建议将适用于Sr、Nd、Pb和Os 幔源镁铁质岩的放射成因示踪系统， 超镁铁岩进一步界定地幔的性质 油气藏、它们在地幔中的位置及其形成方式 起源和进化 私家侦探们提议广泛的 同位素研究的海洋玄武岩的地方， 端元地幔储层DMM、EMI、EM 2和HIMU是 最明显的。 EM 2超镁铁岩包体和 将对HIMU岛进行分析，以与相关的 玄武岩 认识到一个新的地幔储层， 建议下地幔，将探索的Os同位素 对Ascension岛玄武岩和 喀麦隆线。 地幔演化的早期阶段 (2.5- 3.7亿岁） Sr、Nd、Pb和Os的研究 太古宙镁铁质岩原生岩浆矿物研究 岩石化学分析方法 利用Re/Os的固有优势 在研究早期地幔过程（吸积作用） 和核心形成）和现今的过程（衍生 来自远古海洋地壳的地幔柱 地幔），PI建议研究参数， 控制Re和Os的地球化学行为。这将 涉及Re和Os分配的自然研究 岩浆与地幔矿物（硅酸盐、硫化物、氧化物 和金属），以及Re-Os溶解度的实验研究 以及金属、硅酸盐熔体和硫化物之间的分配 液体

This renewal proposal will apply the Sr, Nd, Pb, and Os radiogenic tracer systems to mantle-derived mafic and ultramafic rocks to further delimit the character of mantle reservoirs, their location in the mantle and their mode of origin and evolution. The P.I.s propose extensive Os isotope studies of oceanic basalts from localities where the end-member mantle reservoirs DMM, EMI, EM 2 and HIMU are most strongly evident. Ultramafic xenoliths from EM 2 and HIMU islands will be analyzed to compare with the associated basalts. The recognition of a new mantle reservoir, proposed to be lower mantle, will be explored by Os isotope tracer studies of basalts from the islands of Ascension and the Cameroon Line. The early stages of mantle evolution (2.5 - 3.7 b.y.) will be studied by Sr, Nd, Pb and Os studies of primary magmatic minerals from Archean mafic rocks. An to utilize the inherent strengths of the Re/Os system in studying both early mantle processes (accretion and core formation) and present-day processes (derivation of plumes from ancient oceanic crust stored in the lower mantle), the P.I.s propose to study the parameters which control the geochemical behavior of Re and Os. This will involve both natural studies of the Re and Os partitioning between magma and mantle minerals (silicate, sulfide, oxide and metal), and experimental studies of Re - Os solubility and partitioning between metal, silicate melt and sulfide liquid.