新疆北部古生代大陆增生构造

摘要

古生代亚洲中部是一幅两陆夹一洋、洋中多地体的构造图案，大地构造框架与现代西南太平洋格局十分相似。中亚造山带是晚古生代复杂地体的拼贴带。新疆北部古生代存在4类成因的8个地体构造。它们以裂解陆块地层块体、海山和火山弧的形式散布在中蒙大洋中，诸地体间是一系列的小洋盆。晚古生代，这些地体开始彼此拼贴并导致强烈推覆作用。石炭纪末-二叠纪初，中蒙大洋闭合，散布其中的诸地体分别增生到塔里木大陆北缘和西伯利亚大陆南缘。北天山-准噶尔地区6条蛇绿岩带记录了诸地体间碰撞事件。%During Paleozoic,two continental plates(Siberian and Tarim)andone ocean(Sino-Mongolian) occurred in the Central Asia including the northern Xinjiang region containing 8 allochthonous terranes swhich were situated in the ancient Sino-Mongolian occean.The tectonic framework of the Paleozoic northern Xinjiang was similar to Southwest Pacific today.The eight terranes include three split continental fragments(Yili,Turpan-Ha in short) and Junggar(?);one Yangzi-type stratigraphic body (Huangchaopo),three volcanic arcs(Bogda,Harlik,Easterm Junggar or Beitashan) and one seamont (Westerm Junggar oor Darbut).A series of small oceanic basins distributed among these terranes.During the Late Paleozoic,these terranes started amalgamation each other caused by closure of the Sino-Mongolian Ocean and ledt to a strongly region-scale ductile thrusting and strike-slip tectonics.From the end of Carboniferous to Early Permian,the Sino Mongolian ocean and several inter-terrane small oceanic basins were completely closed and then these terranes accreted on the margins of Siberian and Tarim continents.The 6 ophiolitic melange zones among terranes recorded this collision event.This paper concludes that the Central Asian belt was resulted from a Late Paleozoic amalgamation and accretion by complexes terranes.