准噶尔盆地东北缘中侏罗世逆冲构造变形及其地质意义

Thrust structural deformation of Middle Jurassic in Northeastern Junggar Basin and its implication on geological research

主要依据准噶尔盆地东北缘青格里底山前冲断带二维地震剖面的精细地质解释,并结合临近阿尔泰造山带燕山期花岗岩的同位素定年,认为准噶尔盆地东北缘在中侏罗世存在逆冲构造变形.该构造变形发生于中侏罗统西山窑组(J2x)沉积期,形成了走向北西、倾向北东的逆断层及断层传播褶皱,表明其时准噶尔盆地东北缘曾受到来自于北东方向的挤压应力作用,其力源可能和西伯利亚板块与蒙古-华北板块的碰撞、拼贴事件有关,是蒙古-鄂霍次克洋闭合的陆内反映.这对于促进北疆地区构造变形与盆山关系的研究具有重要意义.

Based on the 2D seismic profile interpretation in the thrust belt at the front of Qinggelidi Mountain in northeastern Junggar Basin and combined with isotopic dating of Yanshanian granites in nearby Altay orogenic belt,it is confirmed that the thrust deformation exist in northeastern Junggar Basin in Middle Jurassic.The structural deformation started in the sedimentary period of Xishanyao Formation（J2x） in Middle Jurassic,formed the NW-SE trending and NE dipping thrust faults and fault-propagation fold,which indicate that the main force comes from the stress force of NE.It is quite possibilly caused by the collision between the Siberian plate and Mongolia-North China Plate,as a result of the Mongolia-Okhotsk ocean closure in the land area.This is important for understanding the structural deformation and orogen-basin coupling in north Xinjiang Province.