塔里木盆地温宿凸起构造特征新认识

New understanding of tectonic characteristic of the Wensu salient in Tarim Basin

温宿凸起位于塔里木盆地西北缘,平面上呈北东-南西向展布。本文从温宿凸起周缘及内部断裂构造解释入手,结合区域地质结构特征、构造单元划分和构造演化研究,认为温宿凸起的形成和演化主要受古木别孜和沙井子两条主断裂控制,表现为夹持在乌什凹陷和阿瓦提凹陷中间的一个古隆起。温宿凸起内部发育一系列次级断裂,将其划分为阿克苏低凸带、阿克雅断凸带、古木别孜断裂带和沙井子过渡带4个构造单元。温宿凸起具有长期隆升、短期沉降的特点:在加里东晚期-喜马拉雅早期,受两条边界主断裂形成并持续活动的影响,温宿凸起长期隆升,造成了其地层的广泛剥蚀;喜马拉雅中期为温宿凸起稳定沉降阶段,沉积了新近系吉迪克组碎屑岩沉积。喜马拉雅晚期差异隆升形成西高东低的大型鼻状构造背景,东部接受了新近系康村组、库车组沉积,西部高部位未接受沉积。边界断裂定型后,温宿凸起亦最终定型,形成了现今的构造面貌。综合研究认为,温宿凸起和塔北隆起构造性质有显著差异,二者为不同构造单元,应将其归属为柯坪断隆而非塔北隆起。喀拉玉尔滚断裂为塔里木盆地一级构造单元塔北隆起和柯坪断隆的界线。本文研究成果对指导温宿凸起勘探生产、重新认识塔里木盆地西北部构造演化和构造格局有重要意义。

The Wensu salient locates in the northwestern margin of the Tarim Basin.It extends in NE-SW direction.Based on interpretation of the fault system in and around,as well as the regional geological structure characteristics,tectonic unit division and tectonic evolution,this paper points out that the formation and evolution of Wensu salient is mainly controlled by two major faults,i.e.,the Gumubiezi fault and the Shajingzi fault.It was a paleo-uplift clamped by Wushi sag and Awati sag.Series secondary faults were developed in the Wensu salient,and divided it into Akesu low-bulge belt,Akeya fault-bulge belt,Gumubiezi fracture belt and Shajingzi transitional belt.The Wensu salient is featured by long-term uplift and short-term depression.During the Late Caledonian to Early Himalayan,influenced by the formation and re-activity of the two boundary faults,the Wensu salient upraised steadily,with simultaneous layer corrosion.During the Middle Himalayan Period,the Wensu salient was at its stable subsidence stage,deposited with the clastic rocks of Neogene Jidike Formation.During the Late Himalayan Period,a large nasal structure,i.e.,lower eastern part and higher western part,was developed in the Wensu salient due to differential uplift.The former was deposited with Neogene Kangcun Formation and Kuqa Formation,while the latter was persistently corroded.When the two boundary faults finalized,the Wensu salient also finalized and formed the present tectonic features.It is concluded that the Wensu salient is a different tectonic unit from the Tabei uplift,and should be classified into the Kalpin fault-uplift.The Kalayuergun fault is the boundary between Tabei uplift and Kalpin fault-uplift,which are two of the first-order tectonic units of the Tarim Basin.This study is of great significance for guiding exploration and production in Wensu salient,and re-understanding the tectonic evolution and framework of the northwestern Tarim Basin.