内蒙古中部石拐侏罗纪陆相含煤盆地构造变形

对华北陆块北缘大青山推覆构造前缘石拐侏罗纪陆相含煤盆地的构造进行了分析。结果表明:早侏罗世早期,石拐盆地受NNE-SSW方向的拉张作用力,形成近东西走向的断陷盆地,而后沉积了早-中侏罗世五当沟组含煤沉积;中侏罗世末受近东西向挤压,在早先沉积地层中形成一套共轭节理;晚侏罗世受大青山推覆构造影响,盆地内侏罗系形成一系列代表推覆构造体系前缘带的紧闭同斜-直立宽缓褶皱及断层相关断层,具明显构造分带性。早侏罗世早期的拉张可能是印支造山后地壳的伸展垮塌,而晚侏罗世的挤压可能是板缘碰撞的板内响应。

Tectonic deformation of Jurassic Shiguai coal basin in central Inner Mongolia

Through the analysis of typical structures formed in Shiguai basin on the front of Daqingshan nappe system,it is indicated that in the early of Early Jurassic the NNE-SSE trending extension stress controlled the basin and formed the nearly east-treading fault basin,then the coal-bearing Wudanggou Formation deposited.In the end of Middle Jurassic,Shiguai basin endured the near east-west trending pressure and formed a series of conjugate joints.During the Late Jurassic episode,controlled by the Daqingshan nappe structure,a series of close isoclinal folds and open folds and fault-related folds was formed in the sedimentary blanket.The early Early Jurassic extension would be the result of collapse of the crust thicken during Indosinian orogenic movement,and the late Late Jurassic pressure would be the intraplate response of collision on plate margin.