松辽盆地上古生界构造格局及演化探究

松辽盆地位于华北板块北部,兴安地块东缘,是北东向展布的宽广断陷盆地。综合最新区域地质资料、钻井资料和重磁资料,对松辽盆地上古生界分布特征进行了分析。通过重磁资料和地震-地质联合剖面解释,确定了盆地内12条骨架断裂位置和活动期次,并认为盆地上古生界具有"两坳夹一隆"的构造特征。结合东北地区构造演化规律,认为盆地构造运动主要为四个阶段。第一阶段:兴安地块与松嫩地块大致沿黑河—嫩江—扎兰屯一带在早石炭世末发生碰撞拼接,造成本区NWW—SEE方向的挤压变形作用,形成"两坳夹一隆"的总体构造格局。第二阶段:沿西拉木伦河断裂,佳—蒙地块和华北板块于二叠纪末碰撞拼接,由NS向挤压形成EW向宽缓褶皱。第三阶段:中生代(侏罗纪)由于西太平洋板块斜向俯冲,NE向压扭作用形成NE—NNE向褶皱和左行走滑断裂。第四阶段:中生代(110 Ma)形成NW向脆性断裂构造变形。

Research on Upper Paleozoic tectonic framework and evolution of Songliao Basin

The Songliao Basin locates the north of North China Plate， and the east of Xing'an block． It is con- sidered as a NE- trending fault broad rift basin． The authors synthesize the latest regional geological data，drilling data，and gravity and magnetism data to analyze the Upper Paleozoic distribution characteristics of the Songliao Ba- sin． Based on the interpretation of gravity and magnetic data and seismic- geology section，the authors determine the location and active stages of the 12 skeletal faults，and suggest that the Upper Paleozoic basin is characterized in one uplift sided by two depressions． Combined with the tectonic revolutionary regulation of Northeast China，the tectonic evolution of Songliao Basin can be divided into four stages as follows． The first stage demonstrates that， Songnen block and Xing'an block collided roughly along the Heihe- -Neijiang- -Zhalantun suture at the end of Early Carboniferous，resulting in NWW- -SEE- trending compressional deformation，forming the“one uplift sided by two depressions”tectonic framework． The second stage shows that Jiamusi- - Mongolia block and North China plate colli- ded along the Xar Moron suture zone in Late Permian，causing formation of the NS- trending extrusion generated WE-trending relief fold． The third stage represents that the subduction of west Pacific plate beneath the Asian conti- nent in Jurassic，forming the NE- - NEE- trending strick- slip faults． The fourth stage is the period that the Mesozoic NW- trending brittle fracture deformed at the time around 110 Ma．