川西前陆盆地中侏罗统沙溪庙组沉积相及平面展布特征研究

川西前陆盆地中侏罗统沙溪庙组具有巨大的勘探开发潜力,但对研究区沉积相研究成果却相对较少。本文根据岩性组合,岩石颜色,沉积构造等多种因素将研究区沙溪庙组划分出冲积扇、河流、扇三角洲、三角洲和湖泊五个沉积相,并对各沉积亚相构成特征进行了详细的研究。沉积相平面展布特征为物源主要来自于盆地西北部的龙门山,自西北向东南依次为冲积扇相-河流相-三角洲相-扇三角洲相-湖泊相。相的垂向序列反映湖泊具收缩-扩张-再收缩-再扩张的演变过程。

Sedimentary Facies and Its Distribution of the Middle Jurrasic Shaximiao Formation in the West Sichuan Foreland Basin

This paper divides the Middle Jurassic Shaximiao Formation in the west Sichuan foreland basin into 5 sedimentary facies such as alluvial fan,fluvial,fan-shaped delta,delta and lacustrine facies based on rock association,color and sedimentary structure and so on.The alluvial fan,fluvial,delta,fan-shaped delta,and lacustrine facies are distributed one after another southeastwards.The distribution indicates material source from the Longmen Mountains.Vertical series of the facies suggests an evolution of repeated spreading and contraction of the lake.