Orchid Jinding Lead-zinc Mine Area Ancient Geological Fluid Characteristics And Its Evolution

Papers to the the Beichang-Jiayashan mine segment in Jinding lead-zinc mine in Lanping is the main object of study. On the basis of systematic summary of the geological setting and geological features of the Lanping basin, The paper studies the geological of the ancient groundwater in basin and how does the salt domes affect the formation of deposits. Anatomy of the main ore body of the mining area to study the alteration and mineralization zonation and fluidnature of the ore body. On the other hand, according to the affect of fluid mineralization by the physical and chemical properties of gypsum, papers focus on the study of the contribution that salt tectonics to the formation of deposits. The thesis has made the following conclusions and understanding.(1) In the Beichang-Jiayashan mine segment in Jinding lead-Zinc Mine in Lanping, there are four types of liquid inclusions:pure liquid inclusions,gas-liquid inclusions with rich liquid, gas-liquid inclusions with rich gas and pure gaseous inclusions, and the main inclusions are the pure liquid ones. The homogenization temperature of fluid inclusions in quartz range form70℃to300℃, and in calcite163.2℃to220.1℃, which have two change temperature sectors obviously,160℃～180℃and200℃～220℃. The homogenization temperature of fluid inclusions in celestite range form153.2℃to353.3℃, which have two temperature intervals:150℃～220℃,240℃～350℃.Quartz, calcite,and celestite is closely related to mineralization in the mining area, the inclusions can reflect the geological fluid information in the various stages of Mineralization.(2) Beichang-Jiayashan mine segment in Jinding lead-zinc mine in Lanping has gone through three mineralization stages:Quartz-sphalerite-pyrite stage:the homogenization temperature of fluid inclusions in quartz range form70℃to300℃,with salinity from1.23wt%NaCleq to20.52wt%NaCleq.Sphalerite-galena-pyrite(marcasite)-the celestite stage (the main mineralization stage):the homogenization temperature of fluid inclusions in quartz range form150℃to350℃,with salinity from12wt%NaCleq to 218wt%NaCleq.Galena-Celestite-calcite-gypsum stage:the homogenization temperature of fluid inclusions in quartz range form50℃to220℃,with salinity from1.66wt%NaCleq to8wt%NaCleq.In the mineralization stage, the homogenization temperature and salinity of the ore-forming fluids were shown to change in trend from high to low,with Concrete characterized by high temperature and high salinity fluid shift to the low-temperature low-salinity fluids.(3)In the Beichang-Jiayashan mine segment in Jinding lead-zinc mine in Lanping, In accordance with the nature of the aquifer,the strata can be divided into the impermeable layer, the aquifer and aquitard under the influence of Nappe system. Among them, the Triassic crooked Waigucun group (T3W) for the impermeable layer, the Upper Triassic Sanhedong (T3s):aquiclude or aquitard, Upper Triassic MaiChuqing group (T3m), impermeable layer, the Jurassic Huakaizuo group (J2h)impermeable layer,the Lower Cretaceous Jingxing group (K1j,) for the aquifer, the Upper Triassic Sanhedong (T3s) breccia zone for the aquifer. Impermeable layer hereon behalf of the impermeable boundary, the formation of ore fluid aggregation of thetrap layer aquifer containing seam mining area, the aquitard is possible ore-forming fluid migration pathways.The aquiclude here on behalf of the impermeable boundary, it is the layer of orefluid trap of convergence. The aquifer is also the main mine aquifer in the mining area.(4) The ore-forming fluids contain two end-member of the H2O-rich and CO2-rich components in the Beichang-Jiayashan mine segment in Jinding lead-Zinc Mine in Lanping.At the same time contains a large number of mixed fluid composition by the different proportions of these two end-member components (H2O and CO2). This situation reflects the initial stage of the geological fluidsmost most likely is a mixture fluid in the Jinding metallogenic. In addition, from the test results of calcite and celestite Raman,fluid with CH4is very common in the main mineralization stage and the final stage, This is consistent with previous research information,that the organic inclusions are always be seen in mining area.(5) Paleo-fluid may be hot brines of the basin, the paleo-fluid is made up by meteoric water, organic-rich basin formation water and the CO2-rich fluid from the deep,and these fluids are mixed in the shallow part of the basin. Under the influence of orogenic activity and the constraints of the geological driving forces, the ancient heat of the basin groundwater flow form the edge of the basin to the center of the basin.During migration, geological fluid gradually absorb atmospheric water from the shallow part of the basin, geological fluid absorbed the rich H2O-hydrocarbon fluids when it flows through the organic matter formation.At the same time, the fluid takes away a large number of mineral elements in the source of ore, and the fluid get together in JinDing town at last.In the main mineralization stage, the ore-forming fluids may be mixed with the CO2-rich mantle fluids from the deep, and get together to mineralization in the favorable parts of the structure.