前陆冲断带的后期演化:负反转与再次冲断——以中国新疆和什托洛盖盆地为例

The deuteric evolution of foreland thrust belt:Negative inversion and re-thrust——Take Heshituoluogai Basin in Xinjiang as example

和什托洛盖盆地位于准噶尔西北缘冲断推覆体之上,是一个在中生代由区域应力场性质发生改变时形成的负反转盆地。盆内沉积盖层厚度可达5 000 m,由下侏罗统八道湾组、三工河组,中侏罗统西山窑组、头屯河组以及新生界组成。盆地内断裂发育,可划分为控制盆地格局和构造带展布的北东东向断裂和起调节作用的北西向断裂两组,依据分界断裂可将盆地划分出北部断褶带、中央坳陷带和南部斜坡带3个一级构造单元和7个二级构造单元。盆地的形成演化主要经历了3个时期:印支期在边界断裂不均衡冲断活动下形成盆地雏形;燕山早期是盆地主要发育期,以大规模沉降作用为主;燕山晚期—喜马拉雅山期是盆地的改造期,现今的构造格局基本形成并在喜马拉雅山期后定型。

Heshituoluogai Basin lies on the northwest wedge decke of Junggar in Xinjiang, China. It is a negative inversion basin formed in Mesozoic when the regional stress field changed. The sedimentary cover is composed of Badaowan Formation and Sangonghe Formation of Lower Jurassic,Xishanyao Formation and Toutunhe Formation of Middle Jurassic, and Cenozoic. Its depth could reaches 5 000 m. Fracture develops well in the basin and it could be divided in to NE directions which controls the structural framework and NW direction which performs as adjustive function. It could be divided into three first-degree structural unions and seven second-degree structural unions. The formation and evolution of basin undergoes three periods. The basin rudiment formed during Indo-Chinese epoch when boundary faults thrust unbalanced. It mainly developed in Early Yanshan epoch and a large-scale precipitating action happened. The basin was rebuilt in Late Yanshan epoch and Himalayan epoch and nowadays structural framework formed after Himalayan epoch.