伊犁盆地侏罗系水西沟群层序地层学研究

Research on sequence stratigraphy of Shuixigou Group,Jurassic in Yili Basin

伊犁盆地侏罗系水西沟群是一套在基本一致的构造应力和沉积环境下形成的含煤碎屑岩建造,但在这套地层的中部(三工河组)出现了岩性、颜色的突变,并且对应的测井曲线也出现明显的突坎现象。笔者运用层序地层学的观点,从年代地层、岩性、体系域、沉积韵律以及测井曲线解释等5方面对这一现象进行了分析,认为该群中部存在一不整合面(或层序界面),并尝试对水西沟群层序地层进行重新划分。

The Shuixigou Group, Jurassic in Yili basin is a set of coal-bearing clastic formation formed under basically consistent tectonic stress and sedimentary environment. In the middle of the Group （Sangonghe Formation） abrupt changes appear in the lithology and the colour of rocks, and an abrupt turning in logging curve appears correspondingly. Using the point view of sequence stratigraphy, authors analyse the above phenomenon in aspects of the chrono-stratigraphy, the lithology, the sedimentary system tract, the sedimentary rhythum, as well as the interpretation of logging curves, and suggest that a unconformity surface （or a sequence boundary） exists in the middle of the Group, and try make a re-division of sequence straigraphy for the Shuixigou Group.