藏北多龙矿集区尕尔勤枕状玄武岩地球化学及SHRIMP测年  

Petrogeochemistry and SHRIMP Dating of Ga'erqin Pillow Basalt in Duolong,Northern Tibet

作　　者：林彬[1,2] 唐菊兴 宋扬[1] 王勤[3] 曹华文[4] Michael BAKER 张乐骏 李玉彬[5] LIN Bin;TANG Ju-xing;SONG Yang;WANG Qin;CAO Hua-wen;Michael BAKER;ZHANG Le-jun;LI Yu-bin(MLR Key Laboratory of Metallogeny and Mineral Assessment, Institute of Mineral Resources,Chinese Academy of Geological Sciences, Beijing 100037;Centre of Excellence in Ore Deposit (CODES), University of Tasmania, Hobart, Tasmania, Australia 7005;Chengdu University of Technology, Chengdu, Sichuan 610059;Chengdu Center, China Geological Survey, Chengdu, Sichuan 610081;Institute of Geological Survey of Tibet, Lhasa, Tibet 850001)

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]澳大利亚塔斯马尼亚大学卓越矿床研究中心,澳大利亚塔斯马尼亚霍巴特7005 [3]成都理工大学,四川成都610059 [4]成都地调中心,四川成都610081 [5]西藏地质调查研究院,西藏拉萨850001

出　　处：《地球学报》2017年第5期702-710,共9页Acta Geoscientica Sinica

基　　金：国土资源部公益性行业科研专项(编号:201511017);自然科学基金项目(编号:41402178);中国地质科学院院基本科研业务费(编号:YYWF201608);中国地质调查局二级项目(编号:DD20160026);中国地质调查局中国矿产地质与成矿规律综合集成和服务(矿产地质志)项目(编号:DD20160346);国家留学基金委项目联合资助~~

摘　　要：多龙是西藏班—怒成矿带中最大的斑岩Cu(Au)矿集区,其区域动力学演化历史一直是研究的热点。矿集区内尕尔勤地区侏罗系海相沉积地层中发现了枕状玄武岩块,对其成岩时代和岩石地球化学的研究,将有助于了解班公湖—怒江洋盆的演化历史。岩石地球化学分析显示,枕状玄武岩稀土元素总量较低(∑REE为38.01×10^(–6)~63.56×10^(–6)),轻重稀土分异不明显,标准化配分曲线属于平坦型,表现出E-MORB的特征。离子探针分析(SHRIMP)获得其锆石U-Pb年龄为(298±11)Ma,与区域晚石炭—早二叠地层中基性岩脉和玄武岩时代一致,可能是早二叠世班怒洋初始裂解时期大规模火山活动的产物。Duolong is one of the largest porphyry Cu(Au)ore concentration areas,its dynamic history always beingthe hot topic for study.Pillow basalt was discovered in Jurassic marine sedimentary strata of Ga’erqin area.Geochronological and geochemical study is helpful to revealing the evolution history of Bangong Co-Nujiang Ocean.Geochemical data show that basalt has low REE(ΣREE38.01×10–6~63.56×10–6)and no significant differentiationbetween LREE and HREE.The chondrite-normalized REE patterns are flat,similar to features of E-MORB.SHRIMP dating shows that the age of pillow basalt is(298±11)Ma,coinciding with ages of mafic dykes and basalt in Late Carboniferous to Early Permian strata.All of these phenomena may be the products of large-scale volcanicactivity for the opening of Bannu Ocean in early Permian strata.

关 键 词：SHRIMP测年 岩石地球化学 枕状玄武岩 多龙 西藏 

分 类 号：P588.145[天文地球—岩石学] P59[天文地球—地质学]