湘西北铅锌矿床碳氢氧同位素特征及成矿环境分析

文章简要介绍了湘西北铅锌矿床的成矿地质背景、铅锌元素在地层中的分布规律和岩石中的分布情况,并通过研究湘西北铅锌矿床中的洛塔、花垣、凤凰3个铅锌汞矿床稳定同位素组成特征,阐明了未蚀变的围岩(正常灰岩)碳、氧同位素组成特征、轻微蚀变灰岩的碳、氧同位素组成特征及方解石脉的碳、氧同位素组成特征。根据流体包裹体氢、氧同位素组成特征、流体包裹体的一般特征进一步探讨了成矿物理化学条件如成矿过程中的成矿温度、成矿压力、盐度、成矿流体的化学性质、成矿流体的pH值和Eh值,并试尝提出了湘西北铅锌矿床的成矿模式。认为湘西北铅锌矿床属于密西西比型矿床。

A tentative discussion on genesis of lead-zinc deposits in northwest Hunan

This paper describes in brief the metallogenic geological background of lead-zinc deposits in northwest Hunan. Based on a study of stable isotope composition of the Luota, Huayuan and Fenghuang lead-zinc-mercury deposits, the authors analyzed the characteristic values of the source area, studied sulfur isotope compositions, made a sulfur source analysis, and recounted carbon and oxygen isotope compositions of unaltered wall rock (normal limestone), slightly altered limestone and calcite. In the light of hydrogen and oxygen isotopic compositions and general characteristics of mineral inclusions, the paper further probed into such metallogenic physical and chemical conditions as ore-forming temperature, pressure, salinity and methane concentration, and chemical properties and pH and Eh values of ore-forming fluids. On such a basis, a metallogenic model for lead-zinc deposits in northwest Hunan is tentatively put forward. The lead-zinc deposits in northwest Hunan are typical Mississippi Valley-Type lead-zinc deposits.