扭动-伸展盆地及其层序发育模式:以辽西彰武早白垩世盆地为例

Wrenched-Extensional Basin and Its Sequence Stratigraphic Models: A Case Study from Zhangwu Earlier Cretaceous Basin, West Liaoning Province

彰武盆地是辽西地区发育的众多早白垩世断陷盆地之一.其中早白垩世沙海组、九佛堂组共可划分为13个三级层序,4个二级层序,2个一级层序.盆地发育期经历右旋扭动的过程,包括伸展阶段和扭转阶段两大演化阶段.得益于其合适的大小,整个盆地在层序发育期表现出明显的右旋扭动特征.彰武盆地是拉张伸展盆地和转换伸展盆地的过渡类型,称之为扭动-伸展盆地.作为伸展扭动盆地,彰武盆地层序充填最突出的特点是水进时期变化的物源供给.据此归纳8种层序发育模式,分别是陡坡正常物源供给模式、陡坡充足物源供给模式、缓坡正常物源供给模式、缓坡充足物源供给模式、深水正常物源供给模式、深水充足物源供给模式、深槽模式和台滩模式.

Zhangwu basin is an early Cretaceous fault depression basin in northeast China, underwent dextral transtension and shows obvious responses on sequence development for its appropriate area. With comprehensive utilization of seismic data, logging and drilling, research was conducted on tectonic evolution and sequence stratigraphic models of lower Cretaceous in Zhangwu basin. Jiufotang formation and lower Shahai formation could be divided into 13 three-order sequences, 4 two-order sequences and 2 one-order sequences. 8 types of stratigraphic models are developed, steep slope type with normal sediment supply, steep slope type with abundant sediment supply, gentle slope type with normal sediment supply, gentle slope type with abundant sediment supply, deep water type with normal sediment supply, deep water type with abundant sediment supply, deep groove type and platform type, respectively.