藏南吉隆—萨嘎地区侏罗系两期变形的厘定及其地质意义

吉隆—萨嘎地区侏罗系陆热组和唯美组普遍经历了两期变形:早期主要表现为中—深层次的顺层剪切作用和同斜褶皱,晚期主要表现为中层次的褶皱-逆冲作用。两期变形分别代表了特提斯洋由南向北的俯冲作用以及印度-欧亚板块碰撞造山作用,其变形样式和组合方式记录了板块俯冲-碰撞造山的历史和过程。其中,早期变形使得地层发生重复,是导致该区侏罗系地层厚度大且难以与江孜、羊卓雍错地区对比的主要原因。

Recognition of two-phases of deformation in the Gyirong-Sa' gya zone, southern Xizang during the Jurassic and its geological implications

The Jurassic Lure and Weimei Formations in the Gyirong-Sa'gya zone,southern Xizang went through two-phases of deformation during the Jurassic,including the intermediate to deep bedding shearing and homoclinal folding in the early phase and intermediate depth folding and thrusting in the late phase.The two-phases of deformation have mirrored the subduction of the Tethyan Ocean from south to north and India-Eurasian plate collision and mountain building,respectively.The deformational styles and package patterns have recorded the history and processes of plate subduction,collision and mountain building.The early deformation resulted in the stratigraphic repetition.This is why the Jurassic strata are so tremendous in thickness that they can hardly correlate with those in the Gyangze and Yamzho Yumco areas in Xizang.