准噶尔盆地南缘中段深层构造变形特征及构造转换关系  

Structural deformation and transition relations of the deep structure in the central margin of the southern Junggar Basin

作　　者：周小军[1] 王旭[1] 陈伟[1] 余养里 孟立丰 Zhou Xiaojun;Wang Xu;Chen Wei;Yu Yangli;Meng Lifeng(School of Earth Science and Technology,Southwest Petroleum University,Chengdu610500)

机构地区：[1]西南石油大学地球与科学技术学院,成都610500

出　　处：《地质科学》2020年第2期339-351,共13页Chinese Journal of Geology(Scientia Geologica Sinica)

基　　金：国家科技重大专项(编号:2017ZX05008)资助。

摘　　要：准噶尔盆地南缘属于环青藏高原盆山构造系统的一部分,受新生代以来青藏高原远距离构造传递作用的影响,深部构造期次多,变形十分复杂,地震剖面成像品质很差,导致对其构造变形特征和变形机制的认识存在争议,对横向构造转换关系和纵向构造传递过程方面的研究甚少。本文采用最新宽线地震资料,运用断层相关褶皱变形方法分析了准噶尔南缘中段霍玛吐背斜带中-深部隐伏构造变形特征;通过构造样式、变形强度对比与分析,阐述了霍玛吐背斜横向转换关系;在构造建模与精细解释的基础上,利用平衡剖面和构造正演模拟方法,分析了其构造演化过程,并阐述了纵向构造传递过程。分析认为,霍玛吐背斜带深部主要发育低幅度断层转折褶皱,中部发育复合型构造三角楔,并伴生有次级褶皱调节断层及小型反冲断层;浅部发育断层传播褶皱;横向上主要表现为构造样式相近、构造变形强度发生此消彼长的构造转换关系;纵向上表现为侏罗纪—中新世的低幅度构造变形,并以前展式向盆地方向发生构造挤压传递,上新世经强烈逆冲挤压,形成复合构造三角楔及派生的突发构造,后经强烈挤压逆冲,在浅部形成断层传播褶皱,并使山前带被强烈推举地表,遭受剥蚀。The southern margin of the Junggar Basin is in the circum-Tibetan Plateau Basin and range system.Subjected to the long distance transfer of the tectonic extrusion by the uplift of the Tibetan Plateau since Cenozoic era,the structural deformation is very complex and the seismic imaging is poor,which lead to controversial understanding of the structural deformation characteristic and the mechanics.Moreover,there is few research on the lateral variation between the anticlines and the longitudinal structural transition from the orogenic belt to the basin.Based on the latest wide-line seismic data,the authors study the middle-deep structure characteristic of the Huomatu anticline belt in the central margin of the southern Junggar Basin by the fault-bend fold theory,and illustrate the lateral variation by the comparative analysis of the characteristics and the deformation strength.The process of structural evolution and the longitudinal transition are elaborated by the balanced section and structural forward approaches on the basis of the model building and the fine explanation.There are low-amplitude fault-bend folds in the deep zone and the compound structural triangle wedge,associated with secondary fold-adjusted fault and small back-thrust faults,in the middle zone of the Huomatu anticline belt.The shallow zone develops fault-propagation folds.The lateral transition relation is characterized by similar structural patterns and waxing and waning structural degree.For the longitudinal transition,low amplitude tectonic deformations developed and expanded toward the basin center by structural compression between the Jurassic and Miocene period,and compound structural triangle wedge and pop-up structure formed in the strong compression in the Pliocene Epoch.Subsequently,fault-propagation folds accommodated in the shallow and the piedmont thrust belt was pushed to the surface and denuded.

关 键 词：准噶尔南缘 平衡剖面 断层相关褶皱 构造正演模拟 构造演化 构造三角楔 

分 类 号：P542[天文地球—构造地质学]