新疆萨热克砂砾岩型铜矿床富烃类还原性盆地流体特征  

Hydrocarbon-rich Reducing Basin Fluid with in Sareke Glutenite Type Copper Deposit, Wuqia, Xinjiang

作　　者：贾润幸[1] 方维萱[1] 王磊[1] 郭玉乾[1] 李天成[1] JIA Runxing;FANG Weixuan;WANG Lei;GUO Yuqian;LI Tiancheng(China Non-ferrous Metals Resource Geological Survey, Beijing 100012, China)

机构地区：[1]有色金属矿产地质调查中心,北京100012

出　　处：《大地构造与成矿学》2017年第4期721-733,共13页Geotectonica et Metallogenia

基　　金：新疆萨热克铜矿整装勘查区专项填图与技术应用示范(12120114081501);塔西砂砾岩型铜铅锌矿床成矿规律与找矿预测(201511016)联合资助

摘　　要：新疆萨热克大型砂砾岩型铜矿床含矿地层为上侏罗统库孜贡苏组,与下伏下-中侏罗统煤矿形成"同盆共存"现象。在萨热克铜矿床的铜矿体内,构造裂隙中含较多沥青(有机碳含量达0.11%~2.55%),并与辉铜矿等铜硫化物共生。铜矿石中次生石英、方解石和白云石等胶结矿物包裹体含烃盐水类、含烃盐水-液烃共生类、含烃盐水-气烃共生类、轻质油类等四类富烃类盆地流体的包裹体。研究认为铜矿石中的有机质主要来源于下伏烃源岩煤层,当盆地深部富含有机质的还原性流体沿NE向构造裂隙上侵到渗透率较高的上侏罗统库孜贡苏组上段(J3kz2)砂砾岩层时,该层上部的下白垩统克孜勒苏群下段(K1kz1)褐红色粉砂质泥岩,与下部的上侏罗统库孜贡苏组下段(J3kz1)灰绿色粉砂质泥岩形成封闭的隔水层,还原性流体沿砂砾岩层发生水平渗滤扩散,与盆地中封存的地层水淋滤含铜赤铁矿质砾岩类后形成的含铜氧化相流体混合时,造成了辉铜矿的大量沉淀和碳酸盐等矿物的结晶析出,并沿砾石间隙充填分布。The Sareke deposit is a large glutenite type copper polymetallic deposit hosted in the glutenite rocks of theUpper Kuzigongsu Formation of Upper Jurassic(J3kz2)in the Sarekebayi basin.A coal mine occurs in Lower-MiddleJurassic strata underlying the ore-hosting strata.Bitumen can be observed in the structural fracture of copper orebody,and organic carbon contents of the ores range from0.11%to2.55%.Laser Raman spectrometer analyses showed that thefluid inclusions in the secondary quartz,calcite,or dolomite of the copper ores contain significant amount ofhydrocarbons,especially methane.These inclusions can be divided into hydrocarbon-bearing brine inclusion,liquidhydrocarbon inclusion,gas hydrocarbon inclusion and light oil inclusion.The organic matters in the ores were mainlyderived from the underlying coal bearing rocks.Ascending of the organic rich fluid along the NE trend faults and thehorizontal glutenite layers in the Kuzigongsu Formation of Upper Jurassic might have been retarded by the impermeablelayers in the Lower Cretaceous and the Upper Jurassic,where it mixed with the Cu-bearing fluid evolved fromformation water that leached copper from the glutenite rocks and precipitated chalcocite.

关 键 词：有机质 流体包裹体 砂砾岩型 萨热克铜矿 

分 类 号：P611.1[天文地球—矿床学]