准噶尔盆地东部侏罗系陆相层序地层学初探

A PRELIMINARY DISCUSSION OF JURASSIC NON-MARINE SEQUENCE STRATIGRAPHY,EASTERN JUNGGAR BASIN

对露头、钻井、地震资料的综合研究表明，准噶尔盆地东部侏罗系内部和顶底界共存在８个不整合面。据此可将侏罗系划分为７个沉积层序，各厚１００～３００ｍ。每个沉积层序为一个向上变细的沉积成因的异地正旋回，由低位和高位两个体系域组成。低位体系域以盆地边缘向中心依次展布沉积扇、辫状河、富泥低弯度河、曲流河等相带。高位体系域在现今盆地边界，缺失边缘相粗碎屑沉积，在盆地大面积内由曲流河或沼泽体系组成。不整合面、沉积层序和体系域均受构造升降─静止的多旋回运动所控制。

In eastern Junggar basin, seven Jurassic alluvial depositional sequences bounded by eight unconformities have been delineated from the integrated interpretation of outcrop,drilling and seismic data, each of which is 100￣300m thick,alluvial allocycle thinning upwards, and contains two system tracts of low stand and high stand. In low stand system tract. facies belts of alluvial fan, braided stream, shale-rich,low-sinuosity stream, and meander stream are distributed in consecutive order from the margin to center of the basin. In high stand one, coarse clastic sediments are missing at the margin of the existing basin, which is composed of meander stream or swamp facies throughout the basin. The surface of unconformity. deporsitional sequence,and system tract are all controlled by repeated tectonic uplift subeidence and still.