藏南扎西康大型铅锌银锑多金属矿床叠加改造成矿作用初探  

Remobilization and overprinting in the Zhaxikang Pb-Zn-Ag-Sb polymetal ore deposit,Southern Tibet: Implications for its metallogenesis

作　　者：梁维[1,2] 侯增谦[2] 杨竹森[3] 李振清[3] 黄克贤 张松 李为[6] 郑远川[1] 

机构地区：[1]中国地质大学地球科学与资源学院,北京100083 [2]中国地质科学院地质研究所,北京100037 [3]中国地质科学院矿产资源研究所,北京100037 [4]中国地质矿业总公司,北京100029 [5]中铝力拓勘探有限责任公司,北京100005 [6]中国国土资源经济研究院,廊坊065201

出　　处：《岩石学报》2013年第11期3828-3842,共15页Acta Petrologica Sinica

基　　金：国家重点基础研究发展计划项目(2011CB403106;2011CB403104);中国地质调查局地质调查项目(1212011121253);国际地质对比计划(IGCP/SIDA-600);国家青年科学基金项目(41102033)联合资助

摘　　要：扎西康铅锌银锑多金属矿具有多期多阶段的复杂成矿的特征。结合对区域成矿带、典型矿石结构构造、闪锌矿Fe含量变化、金属成矿元素分带性以及流体演化特征的分析,初步识别和探讨了扎西康多金属矿床叠加改造发生过程:在特提斯喜马拉雅锑金矿带形成前,扎西康即已经是一个粗晶脉状铅锌矿床。后碰撞阶段,地壳伸展,热活动强烈。以岩浆驱动大气水循环形成的地热水为主的区域富锑流体,流经扎西康,早期硫化物成为后期流体沉淀的有效化学障。流体对早期矿体形成的角砾产生再活化、溶蚀、交代作用,活化出铅、锌等元素,形成新的混合流体。该流体在NS向正断层发生运移、充填成矿,此时锌仍以闪锌矿重结晶、沉淀,但其中的铁含量已经降低,而铅与锑等形成硫盐矿物,当Pb被硫盐矿物消耗后则形成辉锑矿。综上,扎西康铅锌银锑多金属矿床是青藏高原陆陆碰撞造山背景下典型的叠加改造型矿床。Zhaxikang polymetallic base metal deposit is characterized by multiple periods and stages of metallogenesis. Combining the study of regional metallogenie belt with the feature of typical ore texture and structure, variation of Fe content in sphalerite, the character of elements zonation in lateral and vertical direction, as well as the results of fluid inclusion thermometry, we summarize the remobilization and overprinting metalllogenesis of Zhaxikang as follows： There had been a coarse-grained sphalerite and galena oreshoot before Tethys Himalaya Sb （ Au ） mineralization originated. In post-collisional stage, the crust of Tibet experienced extension and intensity of igneous activity. Geothermal water forming from Meteoric water driven by igneous extracted Sb from stratum around, which formed regional Sb-bearing fluid. The Sb-bearing fluid flowed through Zhaxikang district, and overprinted the former oreshoot which was an effective geochemical barrier. Then the Sb-bearing fluid and replaced coarse-grained galena and sphaerite, from which removed out lead and zinc to form newly mixing fluid. Additionally, this newly formed fluid migrated along NS direction fault system and crystallized in extension space with form of stockwork, vein and miarolitic type. Zn still in forms of sphalerite with Fe content down, and Pb in forms of sulfosalt with Sb and/or Ag. Finally, stibnite was to crystallize as Pb precipitated completely. To sum up, Zhaxikaug polymetallie base metal deposit was a typical but non-unique remobilization and overpriting ore deposit in Tibet Plateau continent to continent collisional orogenesis and metallogenesis.

关 键 词：成矿期次 元素分带 叠加改造 扎西康 藏南 

分 类 号：P611[天文地球—矿床学]