【摘要】 哀牢山—红河构造带哀牢山段可划分为东部高级变质带和西部低级变质带。构造分析表明:该构造带由3个不同变形域组成,可能代表其经历的3期左行走滑。第1期走滑发生在整个高级变质带,为拉张性左行走滑,形成角闪岩相L型构造岩。第2期走滑形成高级变质带中的高应变带,变形体制接近简单剪切,形成绿片岩相L-S型糜棱岩。第3期主要发生在低级变质带,为挤压性走滑,形成左行逆冲构造格局,并形成低绿片岩相千糜岩。地质年代学数据证明,3期左行走滑的形成时代分别是:距今58~56Ma、27~22Ma和13~12Ma±。哀牢山—红河构造带第1期左行走滑可能对应于印度与欧亚大陆距今60Ma左右的初始碰撞;第2期变形与青藏高原最强的挤压隆升期一致;第3期事件可能代表距今16~13Ma开始的青藏高原物质进一步东挤。哀牢山—红河构造带的3期主要左行走滑均发生在新生代印度与欧亚大陆的汇聚过程中。更多还原

【Abstract】 Two phases of sinistral ductile shearing occurred along the eastern terminal of the Dabie orogen and western terminal of the Su-Lu orogen, which developed during the syn-orogenic period and Early Cretaceous respectively. Only Early Cretaceous sinistral shearing was found in southern part of the Zhangbaling Rise. These shear zones were composite ones, composed of several smaller ductile shear belts. The mylonites in the shear zones showed steep mylonitic foliation and gentle mineral elongation lineation. All of the filed surveys, microstructures and quartz C axis fabrics indicated a sinistral shear sense. Newly-formed mineral assemblages and mineral deformation behaviors demonstrated that both of the earlier and later shear zones along the eastern terminal of the Dabie orogen were developed under metamorphic temperature conditions of middle greenschist facies, the shear zone along southern part of the Zhangbaling Rise was formed under metamorphic temperature conditions of higher greenschist facies, and both of the earlier and later shear zones along the western terminal of the Su-Lu orogen were developed under metamorphic temperature conditions of higher amphibolite facies. Electron microprobe analysis on matrix white mica of the mylonites suggested that the shear zones along the eastern terminal of the Dabie orogen and southern part of the Zhangbaling Rise were developed under low-pressure conditions, and those along the western terminal of the Su-Lu orogen were formed under high-pressure eclogite facies conditions. These detailed structural studies demonstrated that the Tan-Lu fault zone appeared as sinistral strike-slip tectonics during the collision of the North and South China plates, and intense left-lateral displacement took place again along the fault zone in the circum-Pacific domain in the Early Cretaceous.更多还原