Re-Os Isotopic Studies of Crust-Mantle Evolution on the Earth

Re-Os同位素系统具有独特的潜力， 地球的地球化学研究，因为提供的信息， 该系统将补充现有系统 从其他同位素系统，并应提供新的见解， 地幔的地球化学演化，地核的形成， 大陆地壳的形成。 该项目将确定一个 准确的地幔Os同位素生长曲线，估算地幔的 3.6Ga克拉通核母核的地壳停留时间 岩石，更好地了解Re和Os在火成岩中的行为 系统，并估计了目前的Os同位素不均匀性 地幔 技术将基于正在进行的工作， 美国国家标准局（NBS）和DTM研究 准河步行者。 资金将主要用于支付 步行者的工资，并建立一个化学设施在DTM的 Re和Os的分离。首先，将进行分析 通过激光共振电离质谱（RIMS）对 Fassett-Walker 6”RIMS机器在NBS。 后来，一个改进的9” 质谱仪，目前正在建设中的DTM，将是 采用

The Re-Os isotope system has unique potential to contribute to geochemical studies of the earth because information provided by this system will be complementary to that currently available from other isotope systems and should provide new insight on the geochemical evolution of the mantle, formation of the core and creation of continental crust. This project will determine an accurate Os isotope growth curve for the mantle, estimate the crustal residence time of the parents of 3.6 Ga craton core rocks, better understand the behavior of Re and Os in igneous systems and estimate the Os isotope heterogeneity of the present mantle. Techniques will be based on the ongoing work at the National Bureau of Standards (NBS) of J. Fassett and DTM Research Associate R. J. Walker. Funds will be used primarily to pay Walker's salary and to build a chemical facility at DTM for the separation of Re and Os. Initially, analyses will be performed by laser resonance ionization mass spectrometry (RIMS) on the Fassett-Walker 6" RIMS machine at NBS. Later, an improved 9" mass spectrometer, presently under construction at DTM, will be used.