Early Paleozoic tectonic framework and evolutionin the northeast margin of Tarim Basin

The tectonic belt in the northeast margin of Tarim Basin is composed of Tianshan area of Xinjiang and most Beishan area of Gansu-Inner Mongolia border.The collision zone between Early Paleozoic Tarim Plate and Kazakhstan Plate extends from Aqikekuduke fracture zone eastwards to Sihbanjing-Xiaohuangshan ophiolite complex.The region experienced extensive magmatic events during Jinning Movement(800 Ma),and Siberian Plate,Kazakhstan and Tarim Plate once collided and connected with each other over Rodinia super-continent.The pieces broken by paleo-continent of Nanhua-Sinian period,block faulted area of Kazakhsta and Tarim Plate were dispersed into the paleo-Asian Ocean in the form of a multi-island group.The peri-continental area had features of bay sedimentary area in Sinian-Cambrian period,and was broken into a rift zone along Huaniushan-Wufengshan-Zhangfangshan line in late Ordovician period.The crust plate of paleo-Asian ocean subducted southwards along the Weinanya-Jijitaizishan-Baiyunshan-Yueyashan-Xichangjing line,forming Gongpoquan island-arc zone and arc-rear basin of Hongliuhe-Niujuanzi-Jianquanzi line.In late Silurian,granitc magmatic activities were active at the beginning stage of collision.Devonian period saw the main collision stage,during which the magmatic thermal event affected the rising orogenic belt,and the volcanic-mollasse foreland basin was formed in the south margin of Tarim Basin.