青藏高原羌塘地体南缘浅成低温热液成矿系统的保存机制及其重要意义--以铁格隆南超大型矿床为例  

The Preservation System of Epithermal Deposits in South Qiangtang Terrane of Central Tibetan Plateau and Its Significance: A Case Study of the Tiegelongnan Superlarge Deposit

作　　者：宋扬[1] 杨欢欢[1] 林彬[1] 刘治博[1] 王勤[2] 高轲[2] 杨超[1] 方向 SONG Yang;YANG Huan-huan;LIN Bin;LIU Zhi-bo;WANG Qin;GAO Ke;YANG Chao;FANG Xiang(MLR Key Laboratory of Metallogeny and Mineral Assessment, Institute of Mineral Resources,Chinese Academy of Geological Sciences, Beijing 100037;Chengdu University of Technology, Chengdu, Sichuan 610059)

机构地区：[1]中国地质科学院矿产资源研究所,国土资源部成矿作用与资源评价重点实验室,北京100037 [2]成都理工大学,四川成都610059

出　　处：《地球学报》2017年第5期659-669,共11页Acta Geoscientica Sinica

基　　金：国家自然科学基金项目(编号:41402178);中国地质科学院基本科研业务费项目(编号:YYWF201608);国土资源部公益性行业科研专项(编号:201511017);中国地质调查局二级项目(编号:DD20160026)联合资助~~

摘　　要：由于青藏高原隆升不可避免的强烈剥蚀作用,中生代浅成低温热液矿床的形成、保存和发现就需要多种地质因素的耦合。西藏班公湖—怒江成矿带西段新发现的铁格隆南铜矿是一处隐伏、半隐伏的超大型斑岩-浅成低温热液叠加矿床。系统的地质编录发现,矿床的保存得益于成矿后美日切错组火山岩的覆盖。在矿体和火山岩之间发现了古风化壳,并识别出弱风化残积层、残积古土壤、半风化坡积物三种风化剥蚀界面,说明矿床形成以后经历了一定程度的隆升剥蚀。通过成矿系统的保存程度间接估算,118~111 Ma之间最小剥蚀厚度为600~1 200 m,区间剥蚀速率为0.1~0.2,平均0.15 mm/a。矿床形成时的地表高程可能达到2 000~2 500 m。矿床形成于班公湖—怒江洋盆闭合末期,对其剥蚀作用的研究验证了南羌塘地体在早白垩世晚期经历过一次重要的剥蚀过程,同时指示了早白垩世晚期是青藏高原隆升历史的重要时期。The formation and preservation of the Mesozoic epithermal deposits are attributed to many couplinggeological factors during the erosion of the Tibetan Plateau.The newly discovered Tiegelongnan Cu depositin the western part of Bangong Co–Nujiang metallogenic belt in Tibet is a superlarge superimposedporphyry-epithermal deposit.The preservation of the Tiegelongnan deposit resulted from the covered Meiriqiecuoandesite formed after the mineralization according to the systematic geological log.The paleocrust of weatheringdeveloped between the orebody and andesite and the weak weathered eluvial,ancient soil,half-regolith deluvialwas identified,which indicates the uplift and erosion of the Tiegelongnan deposit.The minimum denudationdepth was600~1200m in118~111Ma and the denudation rate was0.1~0.2mm/a with an average of0.15mm/a according to the indirect calculation of the metallogenic system protection.The ancient elevation of theTiegelongnan deposit was about2000~2500m.The Tiegelongnan deposit formed at the last stage of the closureof the Bangong Co–Nujiang Ocean.The research in this paper has confirmed that southern Qiangtang terraneexperienced an important denudation process in the late period of early Cretaceous and indicated the late periodof early Cretaceous was an important period during the uplifting of Tibetan Plateau.

关 键 词：浅成低温热液 斑岩矿床 矿床保存 隆升 班公湖-怒江 西藏 

分 类 号：P611.13[天文地球—矿床学] P588.134[天文地球—地质学]