The Re-Os System in Mantle-Derived Rocks

本文的目的是利用187Re到187Os的衰变作为天然示踪剂，将Re/Os体系应用于地幔演化和地幔岩浆源性质问题。本文的研究重点是：1)比较洋中脊玄武岩与洋岛玄武岩的187Os/186Os比值；2)玄武岩中187Os/186Os和3He/4He的耦合变化说明岩浆来源；3)对北美东部阿巴拉契亚地区中生代拉斑岩的详细记录样品进行系统研究，将确定幔源岩浆生成和演化过程中Re和Os丰度对岩石圈地幔长期Re/Os系统的控制作用。采用负离子热电离质谱（NTIMS）对样品进行187Os/186Os的分析。稀土浓度将继续由SIMS测定。这项工作将使我们对地幔岩浆的起源有更广泛的认识。

The objective of this proposal is to apply the Re/Os system to problems in mantle evolution and the nature of mantle magma sources using the decay of 187Re to 187Os as the natural tracer. This study will focus on 1) comparing the 187Os/186Os ratios of mid-ocean ridge basalts with those of ocean island basalts; 2) the coupled use of 187Os/186Os and 3He/4He variations in basalts elucidating magma sources; 3) a systematic study of carefully documented samples of the Mesozoic Appalachian tholeiite province of eastern North AMerica will determine the controls on Re and Os abundances during generation and evolution of mantle-derived magmas on long-term Re/Os systematics of lithosphere mantle. The samples will be analyzed for 187Os/186Os by negative ion thermal ionization mass spectrometry (NTIMS). Re concentrations will continue to be determined by SIMS. This work should provide a broader understanding of the origin of mantle magmas.