浅成-次火山岩黑云母Cu,Au成矿示踪意义  

Biotite as A Tracer of Cu and Au Mineralization in Hypergene-Subvolcanic Plutons

作　　者：熊小林[1] 石满全[1] 陈繁荣[1] 

机构地区：[1]中国科学院广州地球化学研究所,广州510640

出　　处：《矿床地质》2001年第2期107-111,共5页Mineral Deposits

基　　金：国家重点基础研究项目(G1999943200);国家自然科学基金(49902007;49973022);南京大学等学校重点实

摘　　要：浅成－次火山岩是许多班岩型和斑岩－浅成低温热液复合型铜、金矿床矿质和流体的重要来源，斑岩体初始岩浆的Ｃｕ，Ａｕ丰度，Ｃｌ，Ｆ含量及岩浆结晶时的氧逸度是其能否最终形成含Ｃｕ，Ａｕ流体的关键因素。黑云母是浅成－次火山中酸性侵入体中最常见的铁镁矿物，含有较丰富的 Ｃｕ，Ａｎ及挥发分 Ｃｌ，Ｆ，其 Ｆｅ３＋／（Ｆｅ３＋ ＋Ｆｅ２＋）比值可以反映其结晶时岩浆的氧化还原状态，尤其是斑晶黑云母往往形成于岩浆流体出溶和去气作用发生之前，它能灵敏地指示其母岩浆的初始Ｃｕ，Ａｕ丰度和Ｃｌ，Ｆ含量及氧化还原状态，因此，可以作为成矿物质、成矿流体来源的理想示踪矿物，并可用于评价浅成－次火山侵入体的成矿潜力。在一些斑岩型铜、金矿床和斑岩、浅成低温热液型金、铜矿床分布区开展浅成－次火山侵入体黑云母的成矿示踪研究，对于解决矿床成因和指导找矿实践均具有重要意义。Hypergene-subvolcanic plutons serve as important sources of ore-forming materials and fluids in many porphyry-type and epithermal Cu (Au) ore deposits. Cu and Au abundances, concentrations of such volatiles as Cl, F and S and oxygen fugacity (fo2) of the initial magma are key factors controlling the formation of Cu- and Au-bearing fluids during the late magmatic stage. Biotite is the most common Fe-Mg mineral in the intermediate-acidic hepergene-subvolcanic plutons; its phenocryst composition can usually show initial Cu, Au abundances and Cl, F contents of the parent magma, whereas the Fe3 + /(Fe2+ + Mgz+ ) ratio of biotite may indicate the relative oxygen fugacity of the magma. Biotite can therefore be used as an ideal tracer mineral for Cu and Au mineralization in hypergene-subvolcanic rocks. It is practical for us to carry out an investigation with biotite as a tracer of Cu, Au mineralization in some areas of hepergene-subvolcanic rocks so as to better understand ore genesis and guide ore exploration.

关 键 词：浅成-次火山岩 黑云母 成矿作用 成矿示踪 铜金矿床 成矿物质 

分 类 号：P618.41[天文地球—矿床学] P618.51[天文地球—地质学]