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白秧坪矿床位于滇西北兰坪盆地北部,是一沉积岩容矿的铅锌铜银多金属矿床,矿体赋存于中生代地层中,受断裂构造控制明显.通过成矿期方解石、石英、闪锌矿中流体包裹体研究,以及方解石的C、O和含硫矿物的S、Pb同位素研究,来探讨成矿流体性质及其来源和成矿物质来源.研究表明,白秧坪矿床包裹体一般小于10μm,气液两相为主,成矿流体体系为Ca2+-Na+—K+-Mg2+-Cl--F--NO3-卤水体系,矿床矿物中冰点温度范围为-26.4～-0.2℃,平均为-14.6℃,均一温度集中于120～180℃,盐度为0.35%～24.73%(NaCleq),平均值16.9%(NaCleq),成矿流体密度在0.84～1.11g/cm3之间,平均值1.04g/cm3,成矿压力为28.0～46.9MPa,平均37.6MPa,对应的成矿深度约1058～2452m,平均1555m,集中于1200～1800m;碳质的来源较为均一,矿石中热液方解石中碳源自地层中碳酸盐岩溶解,成矿流体属于盆地流体系统,有大气降水的加入;成矿物质硫来自硫酸盐的热化学还原作用,或者含硫有机质的热分解,金属成矿物质来自沉积地层和盆地基底.
The Baiyangping deposit is a Pb-Zn-Cu-Ag polymetallic deposit hosted by sedimentary rocks and located in the northern part of Lanping Basin, northwestern Yunnan. The orebodies occur in the Mesozoic strata and are controlled by fault structures. Through the calcite, quartz and flash Fluid inclusions in zinc ore and S and Pb isotopic studies of C and O in calcite and S and Pb isotopes of sulfur-bearing minerals to explore the nature of ore-forming fluid and its source and source of metallogenic materials.The study shows that the inclusions in Baiyangping deposit are generally Less than 10μm, mainly gas-liquid two-phase, and the ore-forming fluid system is Ca2 + -Na + -K + -Mg2 + -Cl - F - NO3- brine system. The freezing point temperature range of mineral deposits is -26.4 ~ -0.2 ℃ -14.6 ℃. The homogenization temperature was concentrated in the range of 120-180 ℃. The salinity ranged from 0.35% to 24.73% (NaCleq) with an average of 16.9% (NaCleq). The density of ore-forming fluid ranged from 0.84 to 1.11 g / cm3 with an average of 1.04 The mineralization pressure is 28.0-46.9 MPa with an average of 37.6 MPa and the corresponding metallogenic depth is about 1058- 2452 m with an average of 1555 m, concentrated at 1200-1800 m. The source of carbonaceous is more uniform. Derived from the dissolution of carbonate rocks in the strata. The ore-forming fluid belongs to the fluid system of the basin and is added by the precipitation of the atmosphere. The metallogenic material Thermochemical reduction from sulfate, or a sulfur-containing thermal decomposition of organic matter, into metal minerals from sedimentary strata and basement.