冀中坳陷深县凹陷主伸展期的构造调节带及其对沉积环境的控制作用

Structural accommodation zones in the main extension period and their effects on depositional system in the Shenxian Sag,Jizhong Depression

深县凹陷沙河街组发育的构造调节带控制着沉积体系的迁移路径和平面展布。根据断层的组合特点与断距变化,可将构造调节带分同向、对向、背向及单线4大类。同向和单线调节带主要发育在北部何庄—兵曹—崔家庄一带,规模小,数量多;对向调节带发育在榆科地区和赵家庄地区,规模较大,分布稀疏。背向调节带极不发育。伸展作用的不均一性以及地层力学性质差异是形成调节带的主要因素。单线调节带控制小规模的沉积体穿过断层进入汇水盆地,如衡水断层下降盘中的水下扇;同向调节带控制何庄—西魏村、田家庄、东阳乡等辫状河三角洲的入湖路径和展布特征;对向调节带控制深湖的形成,如赵家庄一带的深湖;而背向调节带造成的正地形起到了阻隔物源作用。

Structural accommodation zone, which is the main type of transfer zone, controls the sediments migration path and surface exhibition in the Shenxian Sag, Jizhong Depression. According to the characteristics of the faults combination（such as dip relation）and throw,four categories, 4 kinds of structural accommodation zones can be summed up. Controlled by basic structural configuration, single line and synthetic accommodation zones, which are relatively small and numerous, mainly develop in the northern part area, such as in Hezhuang, Bingcao and Cuijiazhuang. Convergent accommodation zones, however, which are larger and sparse, mainly formed in the southern part area, such as Yuke and western Zhaojiazhuang. Divergent accommodation zones are rarely found in the Shenxian Sag. Single line accommodation zones may allow minor sedimentary bodies acrossing faults and reaching faulted lake, such as subaqueous fans developed in downthrown side of Hengshui fault. Synthetic accommodation zones control the transportation path into the catchment basin and spread of braided delta in Hezhuang-Xiweicun,Tianjiazhuang, Dongyangxiang. Convergent accommodation zones usually lead to the formation of deep lake, for example in Zhaojiazhuang. Besides, Divergent accommodation zones usually block the sediment transportion by topographic high.