The Early Cenozoic Gerze Thrust System in Northern Tibet
详细信息
- 责任者：Wu Zhenhan (Chinese Academy of Geological Sciences ; Beijing 100037 ; China) ; Ye Peisheng
- 刊名：Acta Geoscientica Sinica
- 出版年：2013
- 卷期：34(1)
- 关键词：推覆构造 ; nappe structure ; 西藏 ; Tibet
- 页码：p.31-38
- 图表：illus., 15 refs.
- 分类号：0300
- issnNo：ISSN1006-3021
- isbnNo：CN11-3474/P
摘要
Intensive thrusting occurred in the Gerze and its adjacent areas of northern Tibet in Early Cenozoic,forming the Gerze Thrust System consisting of thrust faults,tectonic slices and nappes,tectonic windows and accompanied folds.Southward thrusting of the Carboniferous slate and Permian dolomite limestone over the Late Cretaceous-Palaeogene red-beds and Triassic-Jurassic marine strata in Central Qiangtang Uplift formed the Central Qiangtang Thrust,whereas southward thrusting of the Bangoin-Nujiang ophiolites,Jurassic mélange and Triassic-Jurassic marine strata over the Palaeogene red-beds and Early Cretaceous marine sedimentary rocks in southern Qiangtang block formed the South Qiangtang Thrust.Early Cenozoic tectonic emplacement of ophiote slices along the South Qiangtang Thrust led to the formation of three ophiolite belts,accompanied by nappes and thrust sheets of Triassic sandstone and shale,Jurassic limestone and Jurassic mélange in the southern Qiangtang block.The Early Cenozoic thrusts were unconformably covered by the Early Miocene lacustrine deposits and volcanic rocks formed in 23.7～19.1 Ma,indicating that such intensive southward thrust stopped before Early Miocene in the Gerze and its adjacent areas.The minimal southward displacements of the Central Qiangtang Thrust and South Qiangtang Thrust are estimated to be ～100～115 km and ～82～110 km respectively,and the total southward displacement of the Gerze Thrust System is ～182～225 km,corresponding to crustal shortening of(50.3±2.7)% in Early Cenozoic Era.