【作者】 崔志华；

【导师】 许英霞；

【作者基本信息】 河北理工大学 ， 地质工程， 2010， 硕士

【摘要】 在对大东沟铅锌矿床地质特征进行详细描述的基础上,对矿床的成因及找矿潜力分析进行研究。通过流体包裹体岩相学、显微测温、激光拉曼光谱分析、H、O、S、Pb同位素、主量、稀土元素及锆石年龄等地球化学方法进行分析。成矿流体属NaCl-H2O-CO2三元流体体系,均一温度的范围为157.4～312.5℃,主成矿阶段流体包裹体的平均盐度为7.77wt%,密度为0.6～0.825g/cm3,估算成矿压力为115MPa,成矿期后流体的平均盐度为11.33wt%,密度为0.725～0.875g/cm3,估算成矿压力7～10MPa,推测成矿深度为0.7～8.9km,总体上反映了成矿流体演化从较低盐度、较低密度、较高压力向较高盐度、较高密度、较低压力的转变,表明成矿流体主要是经深部循环演化了的大气降水与岩浆水的混合流体,包裹体气相成分中以CO2为主,常见气相成分还有H2O、N2、CH4,且含有一定的H2S,表明成矿流体形成在一个较还原的环境;δ34S在-14.3‰～9.4‰之间,集中在3.0‰～6.0‰之间,变化范围不大,说明硫来自地壳深部或上地幔,Pb同位素组成显示铅主要来源于地幔,有少量地壳铅的加入;矿床成矿大地构造背景为活动陆缘。矿床经历了喷流沉积成矿作用,又有后期热液的改造,可以定为喷流沉积改造型矿床;大东沟及小东沟锆石年龄研究表明,南西方向的火山岩推覆到大东沟厚大沉积层之上,因此南东方向找矿潜力较大。更多还原

【Abstract】 Based on detailed description of the geological features of Dadonggou Pb-Zn ore deposit, the genesis and prospecting potential of the Dagonggou’s Pb-Zn deposit are alalyzed. Petrography and homogenization temperatures of fluid inclusion, Laser Raman spectra of fluid inclusion, H, O, S, Pb isotopic elements, major elements, rare earth elements and SHRIMP U-Pb are tested. The component of the original mineralization fluid system is NaCl-H2O-CO2, the temperature of the original mineralization fluid ranges from 157.4℃to 312.5℃, the average salinity of fluids in the main mineralization stage is 7.77wt%, the density ranges from 0.6g/cm3 to 0.825g/cm3 and the estimated pressure is 115MPa. The average salinity of fluids in the post mineralization stage is 11.33wt%, the density ranges from 0.725g/cm3 to 0.875g/cm3 and the estimated pressure is 7～10MPa. On the whole, the fluid of the mineralization evolution from high pressure, low salinity and low density to low pressure, high salinity and high density, the mineralization depths are about 0.7～8.9km. Then, the ore-forming fluids may belong to a mixed solution between meteoric water and magmatic water. Gaseous phase are enriched in CO2 with minor amounts of H2O, N2, CH4 and H2S, so ore deposit is formed in the reduction environment.δ34S ranges from -14.3‰～9.4‰, concentrates in the range of 3.0‰～6.0‰, and sulfur come from the deep crust or upper mantle, Pb isotopic composition come from mantle with a few crust lead. Geotectonic setting is island arc system, deposit has experienced the sedimentary-exhalative mineralization and hydrothermal alteration which happened in late mineralization, so it can be classified as tansformed sedimentary-exhalative deposit. Through the analysis of SHRIMP U-Pb datas of Dadonggou and Xiaodonggou deposit, volcanic rocks which located in southwest were pushed over into southeast above on thick sediment layer, a great prospecting potential may locate in southeast.更多还原