江汉洞庭盆地水系展布特征与新构造运动

EXTENSION CHARACTERISTICS OF RIVER SYSTEM AND NEOTECTONIC MOVEMENT IN THE JIANGHAN-DONGTING BASIN

利用水系线密度与面密度分布特征，结合野外地质调查等方法，详细研究了江汉洞庭盆地的新构造活动。认为至少全新世以来江汉洞庭盆地普遍沉降，主要沉降带的展布呈“Ｓ”型，“Ｓ”的北端分布于武汉至梁子湖一带，中段沿沙湖—湘阴断裂西侧展布，“Ｓ”的南端由南洞庭、津市、公安沉降区构成。沉降带这种展布格局可能是盆地内北北东向断裂在北东向挤压。

The neotectonic activity of the Jianghan-Dongting basin is discussed detailly by use of distribution features of line and surface densty of river system and in combination with various ways of field geological survey.The results show that the basin are commonly subsided since the Holocene at least and that the extension characteristics of main subsidene zone are similar to pattern of S on the basin,the northern end of which distributes from Wuhan to Lianhzihu region,the central section along the western side of Shahu-Xiangyin fracture,and the southern end is constituded by southern Dongting,Jinshi and Gongan subsidence zones.This extension framework of subsidence zones may be resulted from the consequent torsion ordinary faulting of NNE fracture under the action of tectonic stress field(NE compression and SE stretch) in the basin.