苏北盆地地震地质分析与构造演化

本文籍助地震地质分析方法,在研究苏北盆地反射时间-深度和孔隙率-深度的关系基础上,分析了横穿盆地的两条区域地震剖面,表明盆地内坳陷的边界断层在晚白垩世形成后,持续活动到渐新世末,在始新世早期活动最为强烈,凹陷内部断裂主要形成于始新世和渐新节,后一期断裂作用主要表现在东台坳陷的范围。分析证实泰州组阜宁组为坳陷式的沉积,中始新世至渐新世为箕状凹陷内充填沉积,因此,晚白垩世后苏北盆地的演化模式可分为:热衰减(伴微弱拉张)→岩石圈伸展(热活动加强)→热衰减(整体沉降)三个阶段。

SEISMIC GEOHISTORY ANALYSIS IN NORTHERN JIANGSU BASIN

Using the method of seismic geohistory analysis, we can reconstruct the evolutionary histoty and reveal the time of faulting in basin directly breed upon a seismic interpreted prolife. In this paper,based on relations of velocity—depth and porosity—-depth, the authors analyse two seismic profiles which stretch across northern Jiangsu basin. The results show that the boundary faults of depression and sags in the basin formed in upper Cretaceous,continually activated untill the end of the Oligocene and intently sctivated in the early Eocene. Paults in sags formed during the early Eocene and Oligocene. Faulting in the Oligocene occurred mainly in Dongtai depression. The seismic profiles show that Taizhou group and Funing group were distributed in depression and the strata deposited duing the mid-Eicebe abd Oligocene were distributed in dustpan sags. Those features can be explatined by the basin evolutionary model as following: thermal decay→extension(with extensive thermal activity)→thermal decay.