内蒙古满洲里地区哈拉胜大型银铅锌矿床地质特征及成矿时代

    GEOLOGICAL CHARACTERISTICS AND METALLOGENIC AGE OF THE LARGE SILVER-LEAD-ZINC DEPOSIT IN HALASHENG OF MANZHOULI AREA, INNER MONGOLIA

    • 摘要: 矿床产于哈拉胜火山穹隆中,成矿与火山-岩浆作用关系密切.钻探和高磁资料显示,火山基底为额尔古纳河组,穹隆核部为次火山岩体,盖层塔木兰沟组和满克头鄂博组火山-沉积岩为容矿围岩.共圈定的11条矿体分布于穹隆东北部,受近南北向张性断裂-裂隙控制,产状较陡.4条主矿体长500~1400 m,平均厚度1~3 m,延深一般500~900 m.自岩体至围岩化探异常元素组合依次为Bi(-Pb-Ag-As-Mo)→Ag-Pb-Mo-Cu→Pb-Zn-As→Ag-Pb-Zn-Sb→Ag-Pb-Zn-Sb;矿化元素组合依次为Cu(-Mo-Pb-Zn)→Pb-Zn-Ag→Pb-Ag;围岩蚀变由岩体内部向外依次为硅化-钾化-石英绢云母化→夕卡岩化→玉髓化-绿帘石化-绿泥石化-碳酸盐化.3件岩浆岩锆石U-Pb年龄为161~142 Ma,结合区域典型矿床研究成果,认为矿床成岩成矿于晚侏罗世—早白垩世,成矿年龄为142 Ma.

       

      Abstract: This Ag-Pb-Zn deposit is occurred in the Halasheng volcanic dome, with mineralization closely related to volcano-magmatism. The drilling and high-precision magnetic data show that the volcanic basement is the Ergunahe Formation, with subvolcanic body as the core of the dome and the volcanic-sedimentary cap rocks of Tamulangou and Manketouebo formations as ore-host rocks. The delineated 11 orebodies in the northeast of the dome are controlled by the N-S-trending extensional fault/fracture with steep occurrence. The four main orebodies are 500-1400 m long with an average thickness of 1-3 m and general depths of 500-900 m. The geochemical anomaly element assemblages from the rock body to surrounding rocks are in the order of Bi(-Pb-Ag-As-Mo)→Ag-Pb-Mo-Cu→Pb-Zn-As→Ag-Pb-Zn-Sb→Ag-Pb-Zn-Sb. The mineralized element associations are Cu (-Mo-Pb-Zn)→Pb-Zn-Ag→Pb-Ag in sequence. The wallrock alterations from inside to outside of the rock body are silicification→potash feldspathization→quartz sericitization→skarnization→chalcedonization→epidotization→chloritization→ carbonation successively. The zircon U-Pb isotopic age of 3 magmatic rock samples is 161-142 Ma. Combined with the research of regional typical deposits, it is believed that the diagenesis and mineralization occurred in Late Jurassic to Early Cretaceous with a metallogenic age of 142 Ma.

       

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