Kinematics and age constraints of deformation in a Late Carboniferous accretionary complex in Western Junggar,NW China

作     者：Ji’en Zhang~a,Wenjiao Xiao~(a,*),Chunming Han~a,Songjian Ao~(a,b),Chao Yuan~c,Min Sun~d,Hongyan Geng~d, Guochun Zhao~d,Qianqian Guo~(a,b),Chong Ma~b a State Key Laboratory of Lithospheric Evolution,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China b Graduate University,Chinese Academy of Sciences,Beijing 100049,China c Key Laboratory of Isotope Geochronology and Geochemistry,Guangzhou Institute of Geochemistry,Chinese Academy of Sciences,Guangzhou 510640,China d Department of Earth Sciences,The University of Hong Kong,Hong Kong,China 

会议名称：《中国科学院地质与地球物理研究所第11届（2011年度）学术年会》

会议日期：2012年

学科分类：070904[理学-构造地质学] 0709[理学-地质学] 07[理学] 

基　　金：Funds from the Chinese State 973 Program(2007CB411307) the Innovative Program of the Chinese Academy of Sciences(KZCX2-YW-Q04-08) the Natural Science Foundation of China Projects(40725009 and 40523003) 

关 键 词：West Junggar Accretionary complex Melange Coheret unit Southern Altaids 

摘      要：The Karamay area,situated in the eastern part of Western Junggar,Southern Altaids,contains an ophiolitic melange with ultramafic rocks,gabbro,basalt,chert and limestone,which show typical block-in-matrix structures,and coherent turbidites and *** lithological associations are interpreted as incoherent and coherent series formed in an acaetionary *** the basis of detailed field mapping and analyses of the asymmetry of imbricate thrusts,duplexes,tilted structures,shear band cleavages,and the NW-verging inclined to overturned folds,we conclude that the overall movement in the accretionary complex was *** youngest tuff involved in the deformation contains detrital zircons that have a U-Pb age(LA-MCICP-MS) of 308±7 ***-Ar resistance furnace step-heating of amphibole separates from a diorite dike,which cuts the folded and imbricated rocks in the accretionary prism,yielded a plateau age of 307±2 ***,the age of the deformation in the prism is tightly constrained at 307-308 Ma,implying that the deformation occurred in an extremely short time-span during SE-ward *** contemporaneous occurrence of Baogutu adakite,high-Mg,Sr-enriched and Y-poor dioritic dikes,Miaoergou charnockite,and Maliya mafic rocks,we further suggest the acaetionary complex was cut by near-trench volcanic rocks and plutons possibly due to interaction with a spreading ridge.