云南火德红铅锌矿床叠加成矿作用过程研究

热液硫化物(闪锌矿、方铅矿和黄铁矿)叠加沉积黄铁矿的现象在一些MVT矿床中普遍存在，但是其叠加成矿作用过程还不是很清晰，沉积黄铁矿起到何种作用也缺乏认识，制约了对MVT矿床成因的深入理解。位于扬子板块西南缘的火德红MVT矿床，其热液硫化物与沉积黄铁矿的共存和交代等现象十分明显，是揭示热液硫化物叠加沉积黄铁矿过程、查明沉积黄铁矿作用的理想载体。本项目拟以火德红矿床为例，以热液硫化物和沉积黄铁矿为研究载体，在细致的矿床学研究基础上，通过热液硫化物及其交代沉积黄铁矿的显微结构表征、LA-ICPMS结合Mapping元素分析和NanoSIMS原位S同位素分析等，查明热液硫化物和沉积黄铁矿的时空结构联系，刻画沉积黄铁矿参与MVT矿床形成过程，揭示其在MVT矿床成矿过程中扮演的角色。研究成果对将为深入理解MVT矿床成因提供重要补充信息，并有望为同类型矿床找矿提供理论指导，具有重要的科学价值和现实意义。

The reworking of sedimentary pyrite by hydrothermal sulfides (sphalerite, galena and pyrite) is common in Mississippi-Valley type (MVT) deposits. However, the reworking process and the role of sedimentary pyrite played in MVT ore formation are still unclear, which leads a poor understanding of MVT deposit genesis. Located on the southwestern margin of the Yangtze Block, the Huodehong MVT deposit provides an ideal case to answer these questions. Such deposit is characterized by various replacement of sedimentary pyrite by epigenetic hydrothermal sulfides. Hence, based on a detailed investigation of ore deposit geology, this project will carry out a comprehensive study of microstructures, LA-ICPMS in situ elements (mapping) and NanoSIMS in situ S isotope of sedimentary pyrite and hydrothermal sulfides from the Huodehong deposit. The outcome aims to: i) reveal the temporal and spatial relationship between sedimentary pyrite and hydrothermal sulfides; ii) identify the process of sedimentary pyrite participating in MVT ore formation; and iii) explain what role of sedimentary pyrite played in Pb-Zn mineralization. This study will enrich our understanding of MVT ore genesis and hence provide theoretical guidance for prospecting of similar deposits.