陕甘宁盆地灵盐定地区中下侏罗统充填特征和层序演化

FILLING CHARACTERISTICS AND SEQUENCE EVOLUTION OF MIDDLELOWER JURASSIC IN LINGYANDING REGION, SHANGANNING BASIN

利用陆相层序地层学观点 ,首次对陕甘宁盆地灵盐定地区侏罗系层序及沉积体系进行了划分、对比 ,认为本区可以湖相泥岩的底界及广泛发育的稳定煤层作为准层序的边界 ,并讨论了准层序组内各沉积体系的特征及纵向演化。从而认为本区延安组内部由低位体系域向湖侵体系域演化 ,最终经高位体系域后 ,导致湖泊填积、消亡。

Based on the principle of terrestrial sequence stratigraphy, the Jurassic stratigraphic sequences and depositional system in Lingyanding region are divided and correlated. the Shanganning Basin are divided and correlated. It is regarded the bottom mudstone of lake facies and coal beds as the boundary of parasequence, the Shan ganning Basin. and are divided and correlated. depositional system characteristics and vertical evolution is discussed. Within the Yanan formation the evolution of the depositional system was from low system tract, lake transgression tract, high system tract, at last to aggradation and extinction of lake. The most favorable oil and gas reservoir was formed in the low system tracts and high system tracts. [