伊宁凹陷构造沉降史与主控因素分析

利用伊宁凹陷多口钻/测井、模拟井及地震数据估算了侏罗纪末期地层剥蚀量，且在充分考虑多种因素基础上，应用回剥技术模拟分析了该区中二叠世以来构造沉降史。研究表明，伊宁凹陷中二叠世以来主要经历了3次快速沉降、2次缓慢沉降与2次区域性快速抬升剥蚀的过程。其中，中二叠世-早三叠世为最大构造沉降期，沉降中心位于中央凹陷带霍城地区，海西期火山裂谷后热沉降作用是造成此次沉降的直接因素；早侏罗世与新近纪以后沉降次之，构造运动形成的差异性升降规律是这2次快速沉降的主要成因；侏罗纪末期-白垩纪早期为主要剥蚀抬升期，伊宁凹陷西部剥蚀强度远远大于东部地区，具有明显的东西差异性。

Tectonic Subsidence of Yining Depression and Its Main Controlling Factors

The Late Jurassic stratigraphic erosion has been estimated according to the data of several drilling wells,simulation wells and seismic data in the Yining Sag.The results show that the structure history of Yining Depression contains three rapid subsidence periods,two slow subsidence periods and two regional rapid uplifting periods since the Middle Permian.The largest subsidence time was in the Middle Permian-Early Triassic Period which was caused by thermal subsidence after Hercynian Volcanic Rifts and the subsidence center was located in Huocheng area of central depression.Rapid subsidence period in Early Jurassic and after Nelgene was less significant,different lifting regularity which was caused by tectonic movement is the main reason for these two rapid subsidence periods.With an obvious east-west difference,Late Jurassic-Early Cretaceous was the major uplift and erosion period,and the eroded intensity of west is much greater than that in the eastern region.