Mechanism of Paleoproterozoic hydrothermal Zn-Pb-Ag-rare metals mineralization in the Black Angel district, central West Greenland

本项目拟对格陵兰岛中部黑天使区古元古代zn - pb - ag稀有金属矿石进行矿物学、地球化学和构造研究。黑天使是地球上最古老的碳酸盐岩铅锌矿床之一，在1973年至1990年期间生产了1120万吨锌铅银矿石。在初步的研究中，我们发现了一种叫做briatite的矿物，这种矿物只在世界上其他11个矿床中发现。初步资料表明，菱铁矿的形成受矿石变形和锗重分布的控制。在本项目中，我们旨在研究与矿石不同构造特征相关的矿体中热液成矿的绝对年龄、过程和重要微量元素（如Cd、Ge、Ga、In）的分布，这些数据将为(1)热液成矿过程中的温度、pH和氧化还原状态以及(2)金属和热液的潜在来源提供重要的约束。该项目的目的是建立一个从流体和金属来源到金属沉淀地点的热液矿化演化的详细模型。我们期望通过微量元素结合硫化物的微观结构分析，在变形和流体控制的元素分布方面得到重要的结果。

In this project, we intend to investigate the mineralogy, geochemistry and structures of Paleoproterozoic Zn-Pb-Ag-rare metals ores in the Black Angel District of central West Greenland. Black Angel represents one of the oldest carbonate-hosted Pb-Zn deposits on Earth, having produced 11.2 Mt Zn-Pb-Ag ore between 1973 and 1990. In a preliminary study, we were able to identify the Ge-mineral briartite, which is only known from 11 other deposits worldwide. Our preliminary data indicate that the formation of briartite is controlled by deformation of the ore and redistribution of Ge.In this project, we aim at investigating the absolute age, processes of hydrothermal mineralization and the distribution of important trace elements (e.g., Cd, Ge, Ga, In) in the orebodies related to different structural features of the ore. The data will provide important constraints on (1) the temperature, pH and redox-state during hydrothermal mineralization, and (2) the potential source for metals and hydrothermal fluid. The aim of the project is to develop a detailed model of the evolution of hydrothermal mineralization from the source of fluids and metals to the site of metal precipitation. We expect important results from trace element combined with microstructural analysis of sulfides with respect to deformation- and fluid- controlled element distribution.