Feature And Sources Of Ore-Forming Fluid In The Huize Lead-Zinc Ore Deposits, Yunnan Province, China

The Huize lead-zinc ore deposits, one of the famous Pb-Zn-Ge basic stations in China, were located in the midst-south of Sichuan-Yunnan-Guizhou polymetal mineralization district (SYG Pb-Zn PMD). They were characterized by large reserve, high grade and high abundance of associated elements (Ag, Ge, Cd, In , Ga, etc.). So, many geologists had been attracted by them. Based on the previous data and the author's viewpoints, the Huize lead-zinc ore deposits were systemically studied in this thesis. Here, the physical and chemical conditions of ore-forming fluid were given out based on the study on the fluid inclusions of hydrothermal calcites and dolomites. Additionally, some high P-T experiments had also been made. On the basis of the combination of these data and the previous data about ore-forming elements and isotopic features, this author tried to study the sources of ore-forming fluid and the transport mechanism and the deposition mechanism of ore-forming materials, understand the relationship of wall rocks, basement rocks and Emeishan basalt and give out a reasonable genetic model of the ore deposits. By this study, we know the variable regularity of ore-forming fluid with variable temperature and pressure, and understand the thermodynamic and dynamic mechanisms of the migration, the enrichment and the deposition of ore-forming elements in the ore deposits so as to guide the exploration and research of the other Pb-Zn ore deposits in PMD. In this thesis, the conclusions and the achievement as following were given out:(1) The ore-forming fluid is characterized by medium temperature(the homogenization temperatures of fluid inclusions in different minerals range mainly from 150°C to 250℃, some higher than 300℃), medium salinity (the salinity of ore-forming fluid ranges from 5 to 21wt% NaCl, average 13.24wt% NaCl), low-to-medium density (the density ranges from 0.546 to 1.129 g/cm~3) and low pressure (the homogeneous instanteous pressure of inclusion ranges from 145 × 10~5Pa to 754× 10~5Pa). In these ore deposits, the mineralization depth is 2200-2450 meters by the research of boiling inclusion. Two peaks occur during the deposition of metallic minerals. One was low temperature stage with the main homogenization temperature of 150-220℃, and the other was medium-high stage with the main homogenization temperature of 300-350℃. Additionally, fluid boiling and fluid immiscibility ever...