青海化隆地区拉水峡铜镍矿床地质、地球化学特征及成因  

Geology,geochemistry and genesis of the Lashuixia Ni-Cu deposit in Hualong area,Qinghai Province

作　　者：高永宝[1,2] 李文渊 谢燮 张照伟[1,2] 郭周平 张江伟 李侃 

机构地区：[1]中国地调局西安地质调查中心,陕西西安710054 [2]长安大学地球科学与国土资源学院,陕西西安710054

出　　处：《地质通报》2012年第5期763-772,共10页Geological Bulletin of China

基　　金：中国地质调查局地质大调查项目<秦祁昆造山系地质构造演化与成矿规律研究>(编号:1212011121088);<新疆北部晚古生代大规模岩浆作用与成矿耦合关系研究>(编号:1212011121092);<祁连-龙首山大火成岩省与金川型铜镍矿关系研究>(编号:1212010911032);<青海省化隆县甘都地区铜镍矿调查评价>(编号:1212010918024);"十一五"国家科技支撑计划项目<秦祁昆成矿域成矿规律与预测示范研究>(编号:2006BAB01A01);<金川含铜镍岩体形成特点及外围岩体地质对比>(编号:2006BAB01B08);国家自然科学基金项目<祁连-龙首山大火成岩省与金川型铜镍矿关系研究>(批准号:40772062);<扬子北缘马元矿床有机质与巨量钼锌成矿关系研究>(批准号:41102050)

摘　　要：拉水峡铜镍矿床位于化隆基性—超基性岩带中,岩体几乎全岩发生铜、镍硫化物矿化,且已遭受强烈蚀变,以角闪岩为主。岩浆期主要金属硫化物矿物组合为磁黄铁矿、黄铜矿、镍黄铁矿;热液蚀变期主要有紫硫镍矿、黄铁矿、黄铜矿、针镍矿等;氧化表生期主要为含镍高岭石、含镍绿泥石、孔雀石等。矿石轻稀土元素富集和负Eu异常明显,说明岩浆演化过程中发生了大量斜长石等的分离结晶作用。∑PGE含量平均为2460.46×10-9,（Pd＋Pt）/（Os＋Ir＋Ru）值为0.40~2.00,表明铂族元素与岩浆深部熔离作用密切相关;但Pt/Pd（0.01~2.62）、Pd/Ir（0.91~8.77）说明热液作用对铂族元素具有一定的富集作用。S同位素组成变化范围很小,δ34S平均值为2.24‰,硫化物中的S以地幔S为主。拉水峡矿床的形成经历了岩浆融离贯入、热液叠加改造及表生氧化作用3个阶段。The Lashuixia Ni-Cu deposit is located in Hualong basic-ultrabasic belt,Qinghai Province.The Lashuixia rock body was altered intensely,mostly mineralized by Ni-Cu sulfides.The major metal minerals include pyrrhotite,chalcopyrite and pentlandite of the magmatic stage,violarite,pyrite and chalcopyrite of the hydrothermal stage,and nickel-bearing kaolinite,nickel-bearing chlorite and malachite of the oxidation stage.The LREE enrichment and negative Eu anomaly indicate that there probably existed fractional crystallization during the process of magmatic evolution.The average content of ∑PGE is 2460.46×10-9.The（Pd＋Pt）/（Os＋Ir＋Ru） ratios（0.40~2.00） are closely related to the deep magma melting.However,because of the hydrothermal alteration,the ratios of Pt/Pd and Pd/Ir are from 0.01 to 2.62 and from 0.91 to 8.77 respectively.The average value of δ34S is 2.24‰,which indicates that S in sulfides was mainly derived from the mantle.On the whole,the ore-forming processes can be divided into magmatic,hydrothermal and oxidation stages.

关 键 词：矿床地质 地球化学 拉水峡铜镍矿床 青海省 

分 类 号：P595[天文地球—地球化学] P597.2[天文地球—地质学]