伊犁盆地伊宁凹陷构造变形特征与主控因素分析

Structural deformation and its controlling factors in the Yining Sag of Yili Basin

基于伊犁盆地伊宁凹陷钻/测井、露头、地震剖面等资料,运用平衡剖面恢复技术,在对伊宁凹陷主干剖面构造演化恢复的基础上,开展构造特征研究工作。研究表明:伊宁凹陷具有"北断南超、南北分带"的构造格局和"北强南弱"的构造变形特点;自二叠纪完全进入陆内发展阶段以来,该区经历了二叠纪末、三叠纪末侏罗纪初、侏罗纪末以及新近纪末4个主要挤压形变期,其中二叠纪末期盆地在东西方向上的挤压变形较为强烈,之后减弱并逐渐发展为以南北向挤压为主,新近纪末为伊宁凹陷南北向主体结构的主要定型期;在南北向为主的挤压应力背景下,伊宁凹陷及周边对冲、逆冲构造发育,形成了以挤压构造为主的构造样式。

Balanced section recovery techniques were used to restore tectonic evolution in the Yining Sag of Yili Basin based on drilling,logging,outcrop and seismic data. The sag is faulted in the north and onlapping in the south. The intensity of tectonic deformation is stronger in the north. The study area entered the continental stage in the Permian,and has experienced four compression periods： end Permian,the end of Triassic to the early Jurassic,end Jurassic and end Neogene. Compressive deformation was the most severe from east to west at the end Permian,and then decreased and changed to north- south compression. The zonation structure from south to north in the sag formed at the end of the Neogene. Hedge and thrust structures developed in the sag and adjacent areas due to north-south compression,resulting in the present compressive tectonic style.