南襄盆地泌阳断陷成盆机制及其成盆史

泌阳断陷成盆史经历了晚白垩世初始断陷期、早第三纪主断陷期和晚第三纪拗陷期三个发展时期，主断陷期是泌阳断陷发生、发展的主要成盆期，可进一步划分为强烈断陷、稳定断陷、断陷消亡３个发展阶段。在泌阳断陷湖盆中，构造作用是沉积层序发育的关键控制因素，它制约着低频层序（盆地充填序列、构造层序、层序组及层序）的发生、发展与形成。另外，控制泌阳断陷形成的北北东向栗园—泌阳断裂带具转换断层性质，在泌阳断陷湖盆早第三纪演化历程中，由于该断裂带的继承性活动，在断陷湖盆东南边缘地带（即栗园附近）形成了一构造性质转换带及地震反射信息复杂带。

STUDY ON BASIN-FORMING HISTORY AND MECHANISM IN BIYANG FAULT-DEPRESSON

The basin-forming history in Biyang fault-depression consists of three evolution stages:initial rift(K2),main rift(E) and downwarp(N).The second stage which is dominating for Biyang fault-depressed basin forming can be further classified into three developing phases:intense,constant and dormant rift.Tectonic event was a key factor to control terrigenous sequence development in Biyang fault-depressed lacustrine basin, and it brought about the formation and evolution of low frequency sequence(including basin-fill sequence,tectonic sequence, sequence sets and sequence).In addition,the NNE Liyuan-Biyang fault belt which contolled the formation of Biyang fault-depression resembles a transform fault.Because of the inherited activity of this fault belt during the evolutionary process of Biyang fault-depressed lacustrine basin in Eogene period, the transform belt of structural feature which is complicated in seismic profiles was formed at the southeastern border of the fault-depressed lacustrine basin(near Liyuan area).