Mineralogical and Isotopic Properties of Hydrothermal Pyrite in Relation to Their Formational Mechanisms

该项目的主要目标是：(1)了解黄铁矿的各种性质（如反射率、硬度、各向异性、晶格、缺硫、电导率、表面反应性、34S）之间的关系，以及黄铁矿形成的具体途径（如取代稳定或亚稳定的一硫化铁，从热液流体中直接沉淀）；以及热液黄铁矿形成过程中多硫化物的生成机理（如H2扩散、H2S - so42反应）；(2)确定黄铁矿与不同水相硫之间的动力学和平衡硫同位素分馏因子。这些目标将通过各种水热实验来实现，在200℃- 350℃的条件下合成二硫化铁矿物，对实验运行产物进行矿物学、化学、电化学和硫同位素研究。该项目的研究结果可提供一套地球化学过程和成矿环境的矿物学和同位素指标，以及热液流体的化学和同位素组成，并为黄铁矿半导体的开发提供有用的信息。

The main objectives of this project are: (1) to understand the relationship among various properties of pyrite (e.g. reflectivity, hardness, anisotropy, lattice cells, sulfur deficiency, conductivity, surface reactivity, 34S), the specific pathways of pyrite formation (e.g. replacement of stable or metastable iron monosulfide, direct precipitation from hydrothermal fluids), and the mechanisms of polysulfide generation (e.g. H2 diffusion, H2S - SO42-reaction) that are involved in the formation of hydrothermal pyrites, and (2) to determine the kinetic and the equilibrium sulfur isotopic fractionation factors between pyrite and various aqueous sulfur species. These objectives will be pursued by a variety of hydrothermal experiments to synthesize iron disulfide minerals at 200oC - 350oC, by mineralogical, chemical, electrochemical and sulfur isotopic investigations of the experimental run products. The results from this project may provide a set of mineralogical and isotopic indicators of geochemical processes and environments of ore formation, and of chemical and isotopic compositions of hydrothermal fluids as well as information useful for the development of pyrite as a semiconductor.