【作者】 贾鹏飞；

【导师】 张静；

【作者基本信息】 中国地质大学（北京） ， 矿物学、岩石学、矿床学， 2011， 硕士

【摘要】 长江中下游是我国东部重要的铁、铜、金多金属成矿带,安徽铜山铜矿位于扬子地块的西北缘,北临大别造山带,是该成矿带安庆^-贵池矿集区中的一个典型的矽卡岩型矿床。矿床产于燕山期铜山岩体与石炭系黄龙^-船山组、二叠系栖霞组地层的接触带中,受岩浆岩、构造、地层和围岩蚀变的共同控制。NE和EW向断裂构造交汇部位控制成矿岩体的就位,控矿和容矿构造主要为接触带构造及不整合面构造等。成矿过程可分为三个阶段:矽卡岩阶段、石英^-硫化物阶段和碳酸盐阶段。各成矿阶段的石榴石、石英和方解石中的流体包裹体岩相学研究结果表明,包裹体主要类型有NaCl^-H₂O型流体包裹体（W型）、含子矿物流体包裹体（S型）。在石榴石和石英中发现晶质熔融包裹体。矽卡岩阶段的流体包裹体主要为W型和S型,均一温度为478⁷69℃,盐度为55.47 wt%,成矿流体具有高温、高盐度的特征;石英^-硫化物阶段的流体包裹体主要为W型,S型次之,均一温度为86.2³99.5℃,盐度为0.18²2.91wt%,成矿流体具有中低温、中低盐度的特征;碳酸盐阶段的流体包裹体全为W型,均一温度为154.6³68.5℃,盐度为0.53²2.91wt%,成矿流体具有中低温、低盐度的特征。从矽卡岩阶段到石英^-硫化物阶段,均一温度和盐度快速降低,从石英^-硫化物阶段到碳酸盐阶段均一温度和盐度变化不明显。经估算,铜山铜矿的成矿压力大约为21Mpa,形成深度可能为2.3km。流体包裹体主要气体组成为H₂O、CO₂、CH₄,液相离子主要为Ca²⁺、K⁺、SO4^2-、Cl^-。从矽卡岩阶段到碳酸盐阶段,CO₂、CH₄、Ca²⁺、SO4^2-、Cl^-含量逐渐降低,K⁺含量逐渐上升,H₂O先减少后增加。包裹体的氢氧同位素表明,成矿流体主要来源于岩浆热液,后期有大气降水混入。硫铅同位素表明,成矿物质来源于岩浆;Re^-Os同位素定年表明,铜山铜矿的成矿时间是150.98±0.78 Ma,为燕山早期。根据不同类型包裹体共生组合及流体演化特征,认为熔体^-流体的不混溶作用和流体的混合作用是金属沉淀的主要原因。更多还原

【Abstract】 The Tongshan copper deposit in Anqing-Guichi Cu-Fe-Au-Mo district is a typical skarn deposit in The Lower Yangtze River metallogentic belt, which is located at the northern margin of the Yangze craton and bordered by the Dabieshan orogenic belt to the north.The ore bodies are related to Tongshan granodiorite and quartz monzonite porphyry, which intruded mainly into Middle Carboniferous Huanglong-Chuanshan Formation, Lower Permian Qixia Formation carbonates and is characterized by porphyritic textures and carbonatization. The location of ore-forming intrusions were controlled by the intersecting places between the NE and EW trending fault structures. The ore-controlling and ore-bearing structures mainly include contact zone, interlayer fractures zone and unconformity structure, etc. The metalogenic processs can be devided into the skarn stage, the quartz-sulfide stage and the carbonate stage. In recent years, new ore layers have been discovered, but the study on fluid inclusions is urgently needed which restricts the ore genesis and metallogenic laws.This paper made further discussion on the source of ore-forming materials and the ore genesis in terms of fluid inclusions. Petrographic observations and temperature results indicate that the main types of fluid inclusions are aqueous inclusions, daughter-mineral-bearing multiphase inclusions, occasionally crystalline melt inclusions（recognized in garnet, quartz） which are the evidence of magmatic skarn. In the skarn stage, the ore-forming fluid is characterized by high temperature and high salinity, Th （homogenization temperature） is 478⁷69℃with salinity of 55.47 wt%. In the quartz-sulfide stage, the ore-forming fluid is characterized by middle-low temperature and middle-low salinity, Th is 86.2³99.5℃with salinity 0.18²2.91wt%; In the carbonate stage, the ore-forming fluid is characterized by middle-low temperature and low salinity, Th ranges from 154.6 to 368.5℃with salinity from 0.53 to 22.91wt%. The Metallogenic pressure is approximately 21Mpa, Metallogenic depth is 2.3km.The results of Raman analysis indicate that major components of gaseous or supercritical species are H₂O, CO₂, CH₄; the major ions in solution are Ca²⁺, K⁺, SO4^2-, Cl^-. From early to late stage, the contents of CO₂, CH₄, Ca²⁺, SO4^2-, Cl^- decreased, K⁺ increased, H₂O decreased firstly and then increased. The D-O isotopic analysis indicates that the ore-forming fluids were mainly magmatic hydrothermal fluids and mixed with meteoric water during the later mineralization stage; The S and Pb isotopic analysis indicate that metallogenic material derived from magma; the Re-Os dating indicates Metallogenic age is 150.98±0.78 Ma, Early Yanshanian.According to the assemblage and evolution characteristics of different fluid inclusions, the immiscibility of melt-fluids and the mixing of fluids are the main causes for mineralization.更多还原