塔西地区富烃类还原性盆地流体与砂砾岩型铜铅锌-铀矿床成矿机制  

Hydrocarbon-rich Basin Fluid with Reductibility and Metallogenic Mechanism for Glutenite-type Cu-Pb-Zn-U Deposits in the Western of Tarim Basin

作　　者：方维萱[1] 贾润幸[1] 郭玉乾[1] 李天成[1] 王磊[1] 黄转盈[1] 

机构地区：[1]有色金属矿产地质调查中心,北京100012

出　　处：《地球科学与环境学报》2016年第6期727-752,共26页Journal of Earth Sciences and Environment

基　　金：国土资源部公益性行业科研专项项目(201511016-1);中国地质调查局地质大调查项目(12120114081501)

摘　　要：塔西地区萨热克大型砂砾岩型铜矿床和乌拉根铅锌矿床进入矿山开发期,今后找矿潜力大但成矿机制不明,制约了成矿与找矿预测。基于构造岩相学和地球化学岩相学,以西南天山造山带为核心,塔西地区前陆盆地、山间盆地和后陆盆地对于砂砾岩型铜矿床、铅锌矿床和铀矿床有不同控制作用:1在西南天山造山带北侧的托云中—新生代后陆盆地系统中,其次级盆地(萨热克巴依中生代山间拉分断陷盆地)上侏罗统库孜贡苏组上段为萨热克式砂砾岩型铜矿赋存层位;2在西南天山造山带南侧的前陆盆地系统中,乌拉根砂砾岩型铅锌矿赋存在下白垩统克孜勒苏群顶部与古近系底部,巴什布拉克大型砂岩型铀矿床赋存在伽师前陆盆地克孜勒苏群中;3在前陆盆地系统中,古近系顶部和新近系渐新统—中新统为砂岩型铜矿床赋存层位。富烃类还原性盆地流体识别构造岩相学标志为沥青化蚀变相、沥青化—褪色化蚀变带、碎裂岩化相和沥青化蚀变相多重耦合结构;地球化学岩相学标志包括富含有机碳,矿物包裹体中含有含烃盐水、气态烃-液态烃-气液态烃、轻质油和沥青等有机质类包裹体,低盐度和中盐度成矿流体,Cu-Ag-Mo同体共生矿体,氧化相铜、硫化相铜和钼硫化物等。砂砾岩型铜铅锌-铀矿床成矿机制主要包括:1同生断裂带由走滑拉分断陷发生构造反转后,转变为挤压收缩体制,即烃源岩大规模生烃-排烃机制;2反转构造带、区域性不整合面、滑脱构造带、高孔隙度和渗透率砾岩等构造岩相带为富烃类还原性盆地流体大规模运移构造通道;3高孔隙度和渗透率砾岩类下部低渗透率泥质粉砂岩和上部含膏泥岩为岩相岩性圈闭构造岩相学标志;4大规模富烃类还原性盆地流体与含铜紫红色铁质杂砾岩(氧化相铜)有多相流体多重耦合结构,可能是砂砾岩型铜矿床大规模富集成矿机�The important Mesozoic-Cenozoic glutenite-type Cu-Pb-Zn-U metallogenic belts are located atthe western of Tarim Basin.The large-size Sareke glutenite-type Cu deposit and Wulagen Pb-Zn deposit are in the development period.They still have high-potential exploration;however,the metallogenic mechanism is not clear,so that it is difficult for metallogenic prediction and prospecting.The tectonic and geochemical lithofacies show that the basin system including foreland,intermountain and hinterland basins around Southwest Tianshan orogenic belt,has different controls on glutenite-type Cu,Pb-Zn and U deposits.Firstly,the Mesozoic intermontane pull-apart graben basin in Sarekebayi,which is a secondary basin attached to Tuoyun Mesozoic-Cenozoic hinterland basin,is located at the northern of Southwest Tianshan orogenic belt.The Sareke glutenite-type Cu deposit is hosted by amaranthine irony conglomerate in the upper part of the Upper Jurassic Kuzigongsu Formation in this basin.Secondly,Wulagen glutenite-type Pb-Zn deposit is hosted between the upper part of the Lower Cretaceous Kezilesu Group and the bottom of Palaeogene located at the foreland basin of the southern part of Southwest Tianshan orogenic belt.However,Bashibulake large-size glutenite-type U deposit is hosted in the Cretaceous Kezilesu Group of Jiashi foreland basin.Finally,the glutenite-type Cu deposit is hosted in the Oligocene-Miocene and the top of the Palaeogene in the foreland basin system.Tectonic petrography features identifying the hydrocarbon-rich basin fluid include bituminization alteration,bituminizationdiscolorous alteration,and multiple coupling patterns between cataclastic lithification and bituminization alteration.Nevertheless,the geochemical petrography features include the rich total organic carbon（TOC）,and the hydrocarbon-bearing salt-water,gas-liquid-gas/liquid hydrocarbon,light oil and asphalt from organic matter inclusions in the mineral inclusions,and the ore-forming fluids with low and middle salinities,and the orebody of Cu-Ag-Mo i

关 键 词：沉积岩型铜矿床 铜铅锌-铀矿床 成矿机制 前陆盆地 后陆盆地 山间拉分断陷盆地 构造岩相学方法 富烃类还原性盆地流体 

分 类 号：P595[天文地球—地球化学] P618.4[天文地球—地质学]