安徽铜陵冬瓜山铜金矿床流体包裹体微量元素地球化学特征及其地质意义  

Trace element geochemical characteristics of fluid inclusions of Dongguashan ore deposit in Tongling,Anhui Province,and their geological implications

作　　者：徐晓春[1] 陆三明[1,2] 谢巧勤[1] 楼金伟[1,2] 褚平利[1] 

机构地区：[1]合肥工业大学资源与环境工程学院,合肥230009 [2]安徽省公益性地质调查管理中心,合肥230001

出　　处：《岩石学报》2008年第8期1865-1874,共10页Acta Petrologica Sinica

基　　金：国家自然科学基金(40472052)资助

摘　　要：安徽铜陵冬瓜山铜金矿床是狮子山矿田中埋藏深度和地质储量最大的矿床,同时发育层控矽卡岩型和斑岩型矿体。该矿床流体成矿从早期到晚期经历了多个矿化阶段。本文选取了钾长石化阶段、矽卡岩化阶段、早石英硫化物阶段和晚石英硫化物阶段矿石中石英的原生流体包裹体进行了 ICP-MS 分析,结果表明,各成矿阶段石英流体包裹体微量元素的陆壳标准化分布曲线具有较好的一致性,显示成矿流体具有统一的来源和演化;流体包裹体的 REE 配分曲线与岩浆岩的稀土元素配分曲线相似,均为平缓右倾型,轻稀土明显富集,LREE/HREE 比值与岩浆岩接近,显示成矿热液具有深部岩浆来源的特征。流体包裹体微量元素的直接分析显示成矿流体为矿质富集的热液流体,且各成矿阶段热液流体中的成矿元素含量高低的变化与相应阶段的矿化强度及矿石品位高低变化相一致,早石英硫化物阶段是矿质集中富集的最佳阶段,至晚石英硫化物阶段可能有浅部热液流体的混入。Dongguashan copper-gold deposit in Tongling, Anhui Province, developed porphyry type and stratified skarn type orebodies. The ore-forming process of the deposit underwent 6 stages such as potassium fieldspar alteration, skarnization, magnetite mineralization, early quartz-sulphide, late quartz-sulphide, and quartz-carbonate according to the mineral assemblages. Trace element and REE compositions of origin fluid inclusions in quartz of potassium fieldspar alteration stage, skarnization stage, early quartzsulphide stage and late quartz-sulphide stage are analyzed with ICP-MS. Chinese continental crust normalized trace element curves of the fluid inclusions in quartz of various mineralization stages have a marked concordance, those show that the ore-forming fluids have a same source and evolution. Chondrite-normalized REE patterns of fluid inclusions in various mineralization stages are similar to those of magmatie rocks in the ore district, those are, REE patterns dip in right gently, LREEs enrich relative to HREEs, and show that the ore-forming fluids derive from deep magma. The direct analysis of fluid inclusions in quartz reflects that the ore-forming fluids are hydrothermal fluids ore-forming material enriched, and the contents of ore-forming metallic elements are distinguish related to the mineralization intensity and ore grade in each ore-forming stage. Early quartz-sulphide stage was the best stage of ore-forming material enrichment and there was shallow hydrothermal fluids added to ore-forming fluids in the late quartz-sulphide stage.

关 键 词：流体包裹体 微量元素和稀土元素 成矿流体特征和演化 冬瓜山铜金矿床 

分 类 号：P595[天文地球—地球化学] P618.41[天文地球—地质学]