西藏东喜马拉雅错那地区亚马荣淡色花岗岩的年代学、地球化学与岩石成因  

Geochronology,geochemistry,and petrogenesis of Yamarong leucogranite in Tsona area,Eastern Himalaya,Tibet

作　　者：石卿尚 黄春梅[1] 雷杭山 齐宁远 佟鑫[1] 赵志丹[1] SHI QingShang HUANG ChunMei LEI HangShan QI NingYuan TONG Xin ZHAO ZhiDan(State Key Laboratory of Geological Processes and Mineral Resources, School of Earth Science and Resources, China University of Geosciences, Beijing 100083, China)

机构地区：[1]地质过程与矿产资源国家重点实验室、中国地质大学地球科学与资源学院,北京100083

出　　处：《岩石学报》2017年第8期2454-2466,共13页Acta Petrologica Sinica

基　　金：国家重点研发计划(2016YFC0600304);国家"973"项目(2015CB452604);国家自然科学基金项目(41273044、41225006);中国地质调查局工作项目(1212011121260、1212011121066);长江学者和创新团队发展计划(IRT1083);中央基本科研业务费专项资金项目(53200859514、53200859758)联合资助

摘　　要：本文通过对东喜马拉雅错那地区亚马荣岩体的地球化学、锆石U-Pb年代学和Hf同位素研究,试图探索亚马荣岩体的形成机制,解释地壳深熔作用过程。锆石U-Pb定年获得两期年龄,分别为14.4Ma和17Ma,结合前人已有结果,本文认为错那地区的深熔作用至少持续5Myr时间。亚马荣岩体具有较高Si O2(71.85%~72.91%)、Al2O3(15.30%~15.67%)含量,较低的Fe2O3T(0.58%~0.90%)、Ca O(0.72%~1.05%)含量,铝饱和指数(A/CNK)为1.08~1.22;锆石Ti温度计、εHf(t)的变化以及大离子亲石元素Rb/Sr比值和Ba含量之间的协变关系都说明,错那淡色花岗岩形成过程中存在多种熔融方式,经历了脱水熔融和水致熔融的转变,发生熔融反应的转变可能与藏南东-西向伸展构造的启动有关。Leucogranite is very important to reveal the dynamics of deep crust. We study the geochemistry,zircon U-Pb chronology and in-suit Hf isotopes on leucogranites from Tsona area,Eastern Himalaya,explore the formation mechanism of the Yamarong leucogranites,and to further explain related problems of continental crustal anatexis. The zircon U-Pb dating displayed two ages of magmatism,14. 4Ma and 17 Ma respectively. Combined with the published data,the time of anatexis in Tsona area had lasted for more than 5Myr. The Yamarong leucogranites have high Si O2（71. 85% - 72. 91%）,Al2O3（15. 30% - 15. 67%）,but low Fe2O3T（0. 58% - 0. 90%）,Ca O（0. 72% - 1. 05%）,with the A/CNK ratios ranging from 1. 08 to 1. 22. The zircon titanium thermometry,εHf（t） value and the covariant relation of Rb/Sr and Ba show that Tsona leucogranties originated from more than one melting reactions.They had experienced the change from dehydration melting to fluid fluxed melting,and the reason of this transformation may be the start of the E-W extension in Southern Tibet.

关 键 词：东喜马拉雅 淡色花岗岩 熔融机制 

分 类 号：P588.121[天文地球—岩石学] P597.3[天文地球—地质学]