The Researches On The Binary Structure And Geochemical Evidence Of Jinding Lead-Zinc Deposit In Yunnan Province

Yunnan Jinding lead-zinc mine which are in the north of the northern section of southwest Sanjiang fold system of Lanping Mesozoic-Cenozoic basins, belong in the Changdu- Simao microplate between Lancang and Jinsha River- Ailaoshan two tectonic belts. In this paper, main ore-controlling structure, host rocks and ore(gangue) mineral structure of Jiayashan and Beichang sandstone open pit are configured to carry out fieldwork system based on lab tests and work on the analysis of geochemical, a source of minerals and ore-forming fluid characteristics, and finally we discusses the genetic mechanism of the deposits and the establishment of a metallogenic model.Electron microprobe analysis indicates that sphalerite S / Zn = 0.947 ~ 1.062, with an average of 1. Pyrite S / Fe = 1.86 ~ 2.056, an average of 1.958. Pyrite sulfur was poor characteristics; ore-forming fluid is substantially free of high temperature mineralization element mineralization on behalf of the environment in low-temperature characteristics. Pyrite Co / Ni = 1.753 ~ 14.379, indicating not become an indicator of genesis.Sulfur isotope studies indicate the source of sulfur is mainly Triassic evaporite sulfur and the participation of mantle sulfur. Most of H2 S are from BSR reaction, a small part in generating TSR effect. Strontium isotope ratios is not only higher than the gypsum ore-forming fluids, it also higher than the same period the global carbonate. Carbon and oxygen isotopes in the calcite indicates the source of CO32-mainly from sedimentary carbonate minerals dissolution or deposition of organic matter oxidation and decarboxylation. It reflects diapirism bring thermal event.Fluid inclusion studies indicate that low salinity fluid with magmatic water mixed feature atmospheric precipitation. Sphalerite homogenization temperature range are in the range of 115 ~ 380 ℃, mainly concentrated in the 120 ~ 210 ℃. Salinity range of 4% ~ 26% NaCleqv, presented "bimodal" feature, mainly in 4% ~ 10% NaCleqv, 12% ~ 20% NaCleqv. On the sphalerite homogeneous temperature-salinity scatter plot picture, sphalerite mainly falls on the typical MVT deposits, brine system and mixed with meteoric range. Celestine uniform temperature in the range of range in the range of 80 ~ 400 ℃, peak "bimodal" feature, mainly concentrated in the 120 ~ 180 ℃, between 230 ~ 350 ℃. Salinity range of 1% ~ 18% NaCleqv, focused on the 8% ~ 16% NaCleqv. Calcite uniform temperature in the range of range in the range of 80 ~ 380 ℃, peak "bimodal" feature, mainly concentrated in the 80 ~ 140 ℃, between 180 ~ 300 ℃. Salinity range of 1% ~ 19% NaCleqv, presented "bimodal" feature, mainly in 3% ~ 5% NaCleqv, within 11% ~ 17% NaCleqv two ranges.Comprehensive understanding of the geological structure and metallogenic age, we believed that the first phase of the late Triassic Jinding lead-zinc mineralization fluid is low temperature and high salinity brine basin environment,BSR reaction played the main role. Ore-forming hydrothermal breccia filling formed limestone breccia type ore mineralization in hydrothermal breccia pipe rises along the sandstone disperses to metasomatic dissolution detrital quartz, feldspar, sandstone formation filling in cracks in the ore type.