西准噶尔达拉布特断裂系构造演化特征

THE STRUCTURAL EVOLUTION OF THE DARABUT FAULT SYSTEM IN WEST JUNGGER

呈北东走向横贯于西准噶尔的达拉布特断裂系,是一组倾向北西的犁状断层。断裂系的形成、发育是由于碰撞后的西伯利亚、哈萨克斯坦和塔里木三大陆块在早石炭世以后,仍在不断地相向运动。由此所形成的断裂系,其早期是以左行陡倾的走滑断层形式出现;中期受陆内俯冲作用的影响,被强烈的推覆构造改造成上陡下缓的犁状断层;娩近时期,断裂处于引张状态,表现为正断层性质,形成了明显的断层地貌。

The Darabut fault system appeared in the northeast strike across the west Jungger area is a set of the plough-shaped faults leaning towards the westnorth direction. The system consists of the Baerleike fault zone, the Mayila fault zone, the Dalabute fault zone and the Ke-Wu fault zone. The system is characterized by the multiphase tectonic activities. At present, the reverse covering nappe and the slips between the strata are very, very clear. The system does not control the strata of the lower Carboniferous and Precarboniferous Series. Only the breakdown faults can be seen. But it obviously controls the strata of the middle carboniferous series and the lower-middle Jurassic ones. In addition,a prominent diversity in the strata thickness of Perimian and the Triassic systems appears on the both sides of the fault as it is of contemporaneous properties. The formation and development of this system resulted from the continuous face-to-face movement of the Talim, Sibelian and Kazakhstanian continental segments after their collision and the early Carboniferous Epoch. As a type of the stress relief form, at the early stage it began to take the shape of the left-lateral strike slip faults. At the middle stage (Triassic period, early and middle Jurassic Epoch)the system was changed into the plough-shaped faults by the strong nappe structure under the continental diving. At the late stage, it was in the state of extention, thus showing that the hanging wall ( the west-north wall ) went down and the foot wall went up. So, the clear fault geomorphologic expression has been formed at present.