Indosinian collision-orogenic system of Chinese continent and its orogenic mechanism
Indosinian collision-orogenic system of Chinese continent and its orogenic mechanism
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作者：
Xu Zhi
古特提斯洋盆的闭合导致了诸多的微块体于晚三叠世至中侏罗世(T3-J2)碰撞，形成东亚大陆南部巨型印支造山系。中国大陆及邻区印支期造山带呈“T”型复合造山作用。研究表明，西印支期“巴彦-北羌塘-南羌塘-拉萨“造山带形成于古特提斯多洋盆、多地体、多岛弧的环境中。古特提斯洋盆的俯冲和闭合，在岛弧、增生楔、高压变质带等地体中产生了广泛的增生造山作用，以及以同劈理褶皱、逆冲断层和走滑断层等地壳变形为特征的多地体碰撞造山作用所产生的大规模造山拼贴作用。东印支造山系是华北陆块与扬子陆块直接碰撞的产物。位于扬子被动边缘之上的松潘-甘孜和南秦岭造山带，表现出上元古界变质基底与古生代-三叠纪盖层之间的大规模深拆离造山机制，以及扬子上地壳强烈的剪切应变。大别-苏鲁造山带扬子地壳的深俯冲作用（100 km）和根部挤压机制，形成了大规模的高压/超高压变质带。
The closure of the large Paleo-Tethyan Ocean at the T3-J2 period induced collisions of many microterrains and formed huge Paleo-Tethys orogenic belts in South Asia,also known as Indosinian orogenic belts. The Indosinian orogenic belts of the Chinese continent and adjacent areas shows a "T"-shaped composite orogeny. Studies have shown that the western Indosinian "Bayan Har-North Qiangtang-South Qiangtang-Lasha"orogenic belts were formed in the Paleo-Tethys setting of multi-ocean basins,multi-terrains and multi-island arcs". Subduction and closure of Paleo-Tethyan ocean basins yielded a wide accretional orogeny in island arcs,accretionary wedges and high-pressure metamorphic belts,as well as large-scale orogenic collage due to multi-terrains collision orogeny charecterized by crustal deformations of syn-cleavage folds,thrusts and strike-slip faults. The eastern Indosinian orogenic system is the direct collision result between the North China and Yangtze blocks. The Songpan-Ganzi and South Qinling orogenic belts located above the Yangtze passive margin show large-scale deep decollement orogenic mechanism between the Upper Proterozoic metamorphic basement and Paleozoic-Triassic covers,as well as intensive shear strain of the Yangtze upper crust. The deep subduction ( 100km) of the Yangtze crust and root extrusion mechanism yielded large-scale high pressure / ultra-high pressure metamorphic belts exposed in the Dabie-Sulu orogenic belt.