南襄盆地中、新生代构造沉降史分析与构造演化

应用沉降史分析和平衡剖面技术,通过对南襄盆地典型井的沉降史模拟及典型剖面的回剥,分析了南襄盆地的沉降史和构造发育史,并对盆地内各凹陷的沉降做出比较,进而反映该盆地的构造沉降特征和构造演化规律。研究表明:南襄盆地经历了中生代和新生代两期成盆过程,划分为白垩纪基底差异裂陷、白垩纪末期基底差异反转、古近纪基底差异裂陷、古近纪末期基底差异反转及新近纪基底整体拗陷5个主要构造演化阶段。两期成盆作用差异较大,盆地沉降中心发生明显迁移,从而造成各凹陷地层结构的差异性。

Mesozoic-Cenozoic Tectonic Subsidence History and Tectonic Revolution of Nanxiang Basin

The subsidence history and the structural history in Nanxiang Basin were analyzed bysubsidence simulating on typical wells and back stripping for typical profiles based on thetechniques of subsidence history and balanced cross section, and the tectonic subsidence characteristics and evolution regularity were demonstrated by contrasting the subsidence of various depressions. The study results indicate that there are five main tectonic evolutionary phases,such as differential faulted depression in Cretaceous basement, differential inversion depression in the late Cretaceous basement, differential faulted depression in Paleogene basement, differential inversion depression in late Paleogene basement and whole de-pression in Neogene basement happened in Nanxiang Basin at two basin-forming stages of Mesozoic-Cenozoic. Obvious discrepancy appears in the process of two basin-forming stages, thesubsiding center migrates obviously, and the different structures of various depressions are formed.