沙雅隆起白垩系卡普沙良群层序地层与沉积模式

Sequence Stratigraphy and Sedimentary Model of Kapushaliang Group of Cretaceous in Shaya Uplift,Tarim Basin

综合运用钻井、测井和地震资料,对塔里木盆地沙雅隆起白垩系卡普沙良群进行了层序地层及沉积相研究。沙雅隆起处于库车前陆盆地的前隆带和隆后坳陷,卡普沙良群对应于一幕逆冲构造活动,其内细分的3个层序(SQ1-SQ3)对应前陆盆地的不同演化阶段。SQ1处于逆冲构造活动的初始期,低位体系域占主导,前隆带中部剥蚀,其两侧斜坡发育来自该剥蚀区的扇三角洲、辫状河三角洲沉积,隆后坳陷则发育来自前隆带及盆地腹部的三角洲沉积;SQ2处于逆冲构造活动增强期,湖侵体系域相对发育,前隆带整体沉降至水下,以滨浅湖沉积为主,隆后坳陷则主要发育曲流河三角洲沉积;SQ3处于逆冲构造活动减弱期和停滞期,以高位体系域的相对发育为特征,前隆带和隆后坳陷成为一体,发育曲流河三角洲和辫状河三角洲沉积。

Based on the drilling, logging and seismic data, the sequence stratigraphy and sedimentary facies of Kapush- aliang group of Cretaceous are studied in Shaya uplift of Tarim basin. Shaya uplift locates in the forebulge and back- age of Kuqa foreland basin, and Kapushaliang group responds to an episodic thrust structural activities of foreland basin. Kapushaliang group is divided into three strata sequences （SQ1-SQ3）, which correspond to different structural evolution satges of foreland basin. SQ1 is in the intial stage of thrust activities,and the lowstand systems tract of SQ1 is dominant. The northern and southern slopes of forebulge develop fan delta and braided river delta, whose sediments come from the denuded middle forebulge. The facies of backage is delta, whose provenance is from the backage and the hinterland of Tarim basin. SQ2 is in the enhanced stage of thrust activities,and the trangressive systems tract of SQ2 is relatively developed. The whole forebulge is under water,and its facies is mainly shore-shallow lacustrine. The backage develops meandering river delta. SQ3 is in the extenuation and stagnate stages,and the highstand systems tract of SQ3 plays a dominant role. The forebulge and backage become one unit,and the facies are mainly comprised of meandering river delta and braided river delta.