Initial movement of the Karakorum Fault in western Tibet:constraints from SHRIMP U-Pb dating of zircons  

作　　者：LI HaiBing Franck VALLI LIU DunYi XU ZhiQin YANG JingSui Nicolas ARNAUD Paul TAPPONNIER Robin LACASSIN CHEN SongYong QI xuexiang 

机构地区：[1]Laboratory of Continental Dynamics, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China [2]Department of Earth Science, Hongkong University, Hongkong, China [3]Institut de Physique du Globe de Paris, 75252 Paris CX05, France [4]Beijing SHRIMP Center, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China [5]ISTEEM-USTL, Place Eugene Bataillon, 34095, Montpellier CX5, France

出　　处：《Chinese Science Bulletin》2007年第8期1089-1100,共12页

基　　金：Supported by the National Natural Science Foundation of China(Grant Nos.40272096 and 40572122)and China Geological Survey(Grant No.1212010610105)

摘　　要：The Karakorum Fault zone(KFZ)plays an important role in understanding the formation,evolvement and deformation of the Tibetan Plateau.The high-T dextral shearing metamorphic rocks,e.g.,mylonites or mylonitized gneisses-granites,locally crop out along the southeastern part of the KFZ in the Ayila Ri’gyüRange area.The SHRIMP U-Pb dating of the syn-kinematic crystallized zircons indicates that the initial age of the KFZ is^27 Ma,~10 Ma older than previous results.The extensive high-T dextral shearing along the KFZ started at least at 27-20 Ma,accompanied by the syn-kinematic emplacement of leuco-granites.Deformation and concomitant fluid circulation during shearing most likely occurred as early as at 25-13 Ma.The KFZ probably grew from southeast to northwest along the fault as a result of continuous convergence between the India plate and Eurasia plate.The Karakorum Fault zone （KFZ） plays an important role in understanding the formation, evolvement and deformation of the Tibetan Plateau. The high-Tdextral shearing metamorphic rocks, e.g., mylonites or mylonitized gneisses-granites, locally crop out along the southeastern part of the KFZ in the Ayila Ri＇gyiJ Range area. The SHRIMP U-Pb dating of the syn-kinemaUc crystallized zircons indicates that the initial age of the KFZ is -27 Ma, -10 Ma older than previous results. The extensive high-T dextral shearing along the KFZ started at least at 27-20 Ma, accompanied by the syn-kinematic emplacement of leuco-granites. Deformation and concomitant fluid circulation during shearing most likely occurred as early as at 25-13 Ma. The KFZ probably grew from southeast to northwest along the fault as a result of continuous convergence between the India plate and Eurasia plate.

关 键 词：西藏西部 喀拉昆仑断裂带 锆石 SHRIMP U-PB 测年 

分 类 号：P542.3[天文地球—构造地质学] P548.2[天文地球—地质学]