Re-Os Isotope Studies of Ultramafic Rocks and Noble Metal Ores

本项目拟利用负热电离质谱技术对苏联科拉半岛佩琴加三铁铁矿及其伴生镍铜矿石的187Re-187Os同位素系统进行研究。本研究的具体目标是：1)获取这些岩石地幔源的Os同位素组成信息，约束Re和Os在地幔熔融过程中的地球化学行为，以及随后产生这些组成不同的套的晶体-液体分异；2)利用Re-Os体系作为示踪剂确定佩城加矿石中贵金属的来源。最终，由于Re和Os的地球化学特征，Re-Os系统将为地幔和地壳的化学演化提供新的见解，并有助于更好地理解贵金属的形成。

This project is to use negative thermal ionization mass spectrometry techniques to examine the 187Re-187Os isotope systematics of the Pechenga ferropicrites and associated Ni-Cu ores (Kola peninsula, USSR). The specific objectives of this research are: 1) to obtain information about the Os isotopic compositions of the mantle sources for these rocks, and constrain the geochemical behavior of Re and Os doing mantle melting and the subsequent crystal-liquid differentiation that produced these compositionally diverse suites, and 2) to utilize the Re-Os system as a tracer for determining the sources of noble metals contained in the Pechenga ores. Ultimately, because of the geochemical characteristics of Re and Os, the Re-Os system will provide new insights into the chemical evolution of the mantle and crust, and lead to a better understanding of noble metal ore formation.