皖浙赣相邻区晚中生代多期构造变形特征及其动力学背景

Late Mesozoic multi-stage structural deformations feature in the adjacent region among Anhui,Zhejiang,and Jiangxi Provinces

通过详细系统的野外地质调查和构造解析,文中在皖浙赣相邻区识别出晚中生代的五期构造变形。第一期为中侏罗世末到早白垩世初的北东东向逆冲-推覆构造,形成时间大约为160～150 Ma;第二期为早白垩世初的高角度正断层和北东东向左行平移断层,形成于150～135 Ma;第三期为早白垩世晚期的北北东向左行平移断层,形成于125～120 Ma;第四期为北东—北东东向右行平移断层,形成于早白垩世末期的100 Ma左右;最后一期为形成于晚白垩世早期（约75 Ma）的北北东向逆冲断层构造。区内晚中生代的多期构造变形与华南和华北板块的最后阶段的碰撞,晚中生代以来太平洋板块在不同阶段向欧亚大陆不同方向的俯冲,甚至与印度板块向北碰撞产生的向东远程挤压效应等诸多作用有关。

Five periods of structural deformations in the Late Mesozoic era have been identified by systematic field investigation and structural analyses.The first one is the NEE trending thrust structure,which took place from the end of the Middle Jurassic to the beginning of the Early Cretaceous,approximately 160-150 Ma.The second one is characterized by the high-angel normal fault and the NNE trending left-laterastrike-slipfault which formed at the beginning of the Early Cretaceous,approximately 150-135 Ma.The third one is the NEE trending left-lateral strike-slip faults,which formed at the late Early Cretaceous,approximately 125-120 Ma.The forth one is the NE-NEE trending right-lateral strike-slip faults formed at the end of the Early Cretaceous,approximately 100 Ma.The last main structural deformation is the top to the NWW thrust with an NNE striking,which formed at the early Late Cretaceous after 75 Ma.The multi-stage deformations are associated with the latest collision of the North China and the South China plate,and with the different directional subduction of the Pacific plate towards the Euro-Asian plate at different stages,and even with the eastward remote extrusion effect of the collision between Indian plate and Euro-Asian plate.