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

本项目旨在研究西格陵兰中部黑天使区古元古代锌铅银稀有金属矿的矿物学、地球化学和构造。黑天使是地球上最古老的碳酸盐铅锌矿床之一，在1973年至1990年期间生产了1120万吨锌铅银矿。在一项初步研究中，我们能够识别锗矿物briartite，这是唯一已知的11个其他矿床在世界各地。初步资料表明，辉绿闪长岩的形成受矿石变形和锗的再分配控制。本项目旨在研究辉绿闪长岩的绝对年龄、热液成矿作用过程和重要微量元素（如锗）的分布。Cd、Ge、Ga、In等元素与矿石的不同构造特征有关。这些数据将对热液成矿过程中的温度、pH和氧化还原状态以及金属和热液流体的潜在来源提供重要的约束。该项目的目的是建立一个详细的模型，说明从流体和金属来源到金属沉淀地点的热液成矿作用的演变。微量元素与硫化物显微结构分析相结合，对变形和流体控制的元素分布有重要意义。

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.