An alternative tectonic model for the Yarlung Zangbo suture zone  

作　　者：LIU XiaoHan JU YiTai WEI LiJie LI GuangWei 

机构地区：[1]Institute of Tibetan Plateau Research,Chinese Academy of Sciences,Beijing 100085,China [2]Mineral Resource Institute of China Metallurgical Geology Bureau,Beijing 100025,China

出　　处：《Science China Earth Sciences》2010年第1期27-41,共15页中国科学（地球科学英文版）

基　　金：supported by Knowledge Innovation Project of the Chinese Academy of Sciences (Grant No.KZCX3-SW-143);National Natural Science Foundation of China (Grant No.40631004)

摘　　要：The new field investigations along the Yarlung Zangbo ophiolites zone show that these series underwent low green-schist metamorphism and were then fractured and occurred as slabs in tectonic melanges,without regional tectonic polarity.No large shear zone in north-south direction has been identified between ophiolite bodies and flysch layers on both side and a conformable contact relationship can be observed locally between them.A great mass of tectonic mélange has been substantiated as submarine olistolith bodies.The Mesozoic sedimentary facies and its evolution in both north and south of the ophiolite zone are corresponding in time.The ophiolite zone has often been divided into parallel branches,separated by narrow flysch slats.There is also a similarity of the Paleozoic and the basement of the High Himalaya,Lhasa and Qiangtang Terranes,and they are distinctly different from those of the Indian continent.The geologic information does not warrant a postulate that the Himalaya and Tibet were once separated by a great ocean;it is therefore consistent with an alternative tectonic model by back-arc basin collapse with its juvenile narrow oceanic crust.The real plate tectonic suture,the Neotethys might be covered under the Miocene Siwalik molasse in the southern slope of the High Himalaya range.Based on the new model,the Neotethyan ocean floor was subducted beneath the Asia since the Late Triassic.The outer continental margin of Eurasia was split from the Lhasa Terrane so that a back-arc basin came into existence.Hemi-pelagic and deep sea sediments were deposited before the Late Cretaceous flysch sedimentation,with the linear juvenile oceanic crust when back-arc volcanism occurred in the Gandese region.The Yarlung Zangbo back-arc basin was eventually eliminated when the High Himalayas were sutured onto Eurasia.The ocean floor lightly underthrusted to north and south sides,sediments of the basin were deformed as fold-thrusting.The Neotethys was eliminated during the Tertiary when India collided with Himalaya arc from The new field investigations along the Yarlung Zangbo ophiolites zone show that these series underwent low green-schist metamorphism and were then fractured and occurred as slabs in tectonic melanges,without regional tectonic polarity.No large shear zone in north-south direction has been identified between ophiolite bodies and flysch layers on both side and a conformable contact relationship can be observed locally between them.A great mass of tectonic mélange has been substantiated as submarine olistolith bodies.The Mesozoic sedimentary facies and its evolution in both north and south of the ophiolite zone are corresponding in time.The ophiolite zone has often been divided into parallel branches,separated by narrow flysch slats.There is also a similarity of the Paleozoic and the basement of the High Himalaya,Lhasa and Qiangtang Terranes,and they are distinctly different from those of the Indian continent.The geologic information does not warrant a postulate that the Himalaya and Tibet were once separated by a great ocean;it is therefore consistent with an alternative tectonic model by back-arc basin collapse with its juvenile narrow oceanic crust.The real plate tectonic suture,the Neotethys might be covered under the Miocene Siwalik molasse in the southern slope of the High Himalaya range.Based on the new model,the Neotethyan ocean floor was subducted beneath the Asia since the Late Triassic.The outer continental margin of Eurasia was split from the Lhasa Terrane so that a back-arc basin came into existence.Hemi-pelagic and deep sea sediments were deposited before the Late Cretaceous flysch sedimentation,with the linear juvenile oceanic crust when back-arc volcanism occurred in the Gandese region.The Yarlung Zangbo back-arc basin was eventually eliminated when the High Himalayas were sutured onto Eurasia.The ocean floor lightly underthrusted to north and south sides,sediments of the basin were deformed as fold-thrusting.The Neotethys was eliminated during the Tertiary when India collided with Himalaya arc from

关 键 词：Yarlung Zangbo OPHIOLITE Zone plate boundary CONTINENTAL MARGINAL arc relic BACK-ARC basin ALTERNATIVE TECTONIC model 

分 类 号：N[自然科学总论]