泌阳凹陷构造活动的沉积响应

Response of sedimentation to structural evolution in Biyang Sag

总结了泌阳断陷湖盆的构造演化 ,以及盆地充填、沉积层序及沉积、沉降中心对构造活动的响应 ,并利用凹陷中沉积、沉降中心的迁移变化特征来确定边界断裂的活动时间 ,恢复湖盆的演化历史 .研究结果表明 :燕山运动的拉分作用、燕山运动之后的盆地边界断裂活动及喜山运动后的拗陷沉积作用形成了本区 3个盆地充填序列及构造层序 ;除了盆地形成、沉积充填序列受构造活动控制外 ,沉积层序的发育也受控于断层幕式活动引起的可容空间及沉积物供给变化的控制 .另外 ,对核二段沉积时期沉积、沉降中心研究可知 ,该时期凹陷内构造格局一直发生变化 ,至核二段一砂组沉积时期 ,两边界断层的活动都大大减弱或基本停止 ,凹陷内沉积格局稳定 ,沉降、沉积中心基本统一 。

In this paper, the structural evolution and the responses of the basin filling, the sedimentary sequence, the sedimentary and subsidence centers to tectonic movement in Biyang Sag are summarized. The movement times of boundary faults are determined and the evolution history is restored based on the migration of sedimentary and subsidence centers. It is shown that the extension action of Yanshanian movement, the movement of boundary faults after Yanshanian movement and the deposition after Himalayan movement determine three basin filling sequences and structural sequence in Biyang Sag. Besides, sedimentary sequence is also controlled directly by the changes of accumulation space and sediment supply resulted from episode movement of faults. The studies on the changes of sedimentation and subsidence centers show that structural situation is unstable in He-2 member. The movements of the two boundary faults are all weakened greatly and the centers of sedimentation and subsidence superpose gradually in the southeast of Biyang Sag until No.1 sandstone group of He-2 member, the basin come really into atrophied rift and fault basin.