鄂西-渝东区膝折构造

KINK STRUCTURE IN THE WEST HUBEI AND EAST CHONGQING

  • 摘要: 包括鄂西-渝东区在内的川东褶皱带的高陡背斜,实际上是多岩层层系在纵弯作用下形成的区域大尺度膝折构造.它是江南-雪峰基底拆离推覆体由SE向NW方向水平挤压作用下中上扬子古生界盆地沉积盖层产生递进(衰减)变形的结果.膝折构造是一种兼具剪切褶皱和弯滑褶皱2种作用特征的褶皱.它往往发生在岩性相对均一的一系列脆性和单层厚度较薄、多层粘性差较大的岩系中.根据褶皱变形强度和几何形态,将鄂西-渝东区的膝折构造进一步划分为挠曲背斜、膝折背斜、箱状背斜、尖棱背斜和寄生背斜5种构造样式.膝折构造控制了川东地区天然气藏的形成与分布.

     

    Abstract: The raised and steep anticline in East Sichuan fold belt including West Hubei and East Chongqing is actually a regional large-scale kink structure formed by multiple strata series under vertically buckling effect.When the Jiangnan-Xuefeng basement decoupling nappe horizontally extruded from SE to NW,the sedimentary cover of Middle-Upper Palaeozoic basin progressively (decreasingly)deformed and resulted in kink structure.The kink structure is characterized by both shear folding and bend folding.It usually occurs in crisp,thin and large viscidity difference strata series with relatively mean lithology.Kink structure in the West Hubei and East Chongqing is divided into 5 types:flexure anticline,kink anticline,box anticline,chervon anticine and parasitic anticline.Kink structure controls natural gas generation and distribution in the East Sichuan.

     

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