西藏申扎—定结南北向构造中段斑岩锆石U-Pb年代学研究  

U-Pb Geochronology Study of Zircon from Porphyry in Middle Section of Xainza-Dinggye North-South Trending Structure

作　　者：李应栩[1] 谢玉玲[2] 李光明[1] 白劲松 唐燕文[4] 周俊杰 郭翔 LI Ying-xu;XIE Yu-ling;LI Guang-ming;BAI Jing-song;TANG Yan-wen;ZHOU Jun-jie;GUO Xiang(Chengdu Centre of China Geological Survey,Chengdu,Sichuan 610081;University of Science and Technology Beijing,Beijing 100083;China Railway Resources Exploration Co.,Ltd.,Beijing 100161;Institute of Geochemistry,Chinese Academy of Sciences,Guiyang,Guizhou 550002)

机构地区：[1]中国地质调查局成都地质调查中心,四川成都610081 [2]北京科技大学土木与资源工程学院,北京100083 [3]中铁资源地质勘查有限公司,北京100161 [4]中国科学院地球化学研究所,贵州贵阳550002

出　　处：《河北地质大学学报》2018年第6期25-32,共8页Journal of Hebei Geo University

基　　金：国家重点基础研究发展计划项目(2016YFC0600308);中国地质调查局地质调查项目(DD20160015);国家自然科学基金项目(41702086)

摘　　要：位于青藏高原南部的南冈底斯斑岩成矿带在西段的朱诺和吉如间百余千米范围内一直缺乏印度—亚洲大陆碰撞后碰撞伸展阶段斑岩活动的报道。论文对该区申扎—定结南北向构造中新发现的拿查和查布斑岩进行了LA-ICP-MS锆石U-Pb年代学研究,发现两套斑岩的侵位结晶时代分别为13.82±0.25Ma(n=11,MSWD=1.7)和13.80±0.22 Ma(n=12,MSWD=0.43),与南冈底斯斑岩矿带中诸多矿床的成矿时代以及成矿斑岩时代一致,填补了该地区的空白,证实了后碰撞斑岩岩浆东西向的连续性。该地区后碰撞伸展阶段形成的矿床剥蚀程度不高,具有进一步开展寻找斑岩型和浅成低温热液型矿床工作的潜力。同时,斑岩中约40 Ma的变质和岩浆成因继承锆石核的发现暗示,在晚碰撞阶段南冈底斯也有过构造-岩浆活动。None porphyry and genetically related deposit has been reported in the area almost 100 km between Zhunuo and Jiru porphyry deposits,both located in the southern Gangdese Porphyry Metallogenic Belt(GPMB)in South Tibetan Plateau and genetically related to porphyry activity at the post-collosional extension setting.Nacha and Chabu porphyry located in the Zainza– Dinggye NS trending structure are newly discovered.The LAICP-MS zircon U-Pb dating of the two porphyry are 13.82±0.25 Ma(n=11,MSWD=1.7)and 13.80±0.22 Ma(n=12,MSWD=0.43)respectively.The two ages are the same as the mineralogenetic epoch of GPMB,which fills the gap in the region and confirm the EW continuity of post-collisional porphyry activity.The erosion of deposits formed at post-collosional extension stage is not strong,which implies further ore potential of porphyry and epithermal type deposits in this area.Meanwhile,metamorphic and magmatic inherited zircon cores with the age of^40 Ma find in the porphyry suggest that,in the late stages of the collision south of Gangdese also had tectonic-magmatic activity.

关 键 词：申扎—定结南北向构造 锆石U-PB定年 斑岩 南冈底斯斑岩成矿带 

分 类 号：P612[天文地球—矿床学]