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(例如反射率、硬度、各向异性、晶胞、缺硫、导电性、表面反应性、34S)之间的关系，黄铁矿形成的具体途径(例如，稳定或亚稳定的硫化铁的置换，(2)确定黄铁矿与各种含水硫物种之间的动力学和平衡硫同位素分馏系数；(2)确定热液黄铁矿形成过程中涉及的多硫化物生成机制(如氢扩散、硫化氢-硫酸盐反应)。这些目标将通过各种水热实验在200oC-350oC合成二硫化铁矿物，通过对实验运行产物的矿物学、化学、电化学和硫同位素研究来实现。这一项目的结果可能提供一套成矿的地球化学过程和环境的矿物学和同位素指示，以及热液的化学和同位素组成，以及有助于开发黄铁矿作为半导体的信息。

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.