南黄海盆地北部凹陷古近纪伸展断层转折褶皱作用

Paleogene extensional fault-bend folding in north depression of southern Yellow Sea basin

王胜利 卢华复 李刚 陈建文 陈国威

Wang Shengli Lu Huafu Li Gang Chen Jianwen Chen Guowei

南黄海北部坳陷为欧亚大陆东部边缘一系列新生代裂谷盆地中的一个。北部坳陷中的东北凹陷为向下逐段变缓、北倾的威海正断层上盘沿断层向北运动导致上盘断层转折褶皱作用而在上盘之上形成的凹陷。伸展断层转折褶皱作用发生过程中,东北凹陷同时接受沉积,形成生长地层,其详实记录了凹陷的发育过程。通过对生长地层的研究,南黄海北部坳陷东北凹陷总的伸展量为10012 m,平均伸展速率为0.225 mm/a。这些数值同亚洲大陆东缘的渤海湾盆地、苏北盆地和东海盆地等古近纪伸展盆地内部单个凹陷的伸展速率具有相似性。

The north depression in the southern Yellow Sea basin is one of the Cenozoic rift basins in the east margin of the Eurasian continent.The northeast sag in the north depression was formed by fault-bend folding of the hanging wall of the north dipping listric Weihai normal fault caused by the northward movement of the hanging wall.In the process of extensional fault-bend folding,the sediments deposited simultaneously and the growth strata were formed in the north sag and recorded the growing process of the northeast sag.Analysis of geometry of the growth strata shows that the northeast sag totally extends 10012 m with an average extension rate of 0.225 mm/a,quite similar to those of single sags in the Paleogene rift basins in east margin of Eurasia,such as the Bohai bay basin,the Subei basin,and the East China Sea basin.

10.11743/ogg20060409