华北地台区晚侏罗世—早白垩世岩相古地理特征

Characteristics of lithofacies paleogeographic during late Jurassic-early Cretaceous in the area of North China platform

华北地台区晚侏罗世沉积区主要位于鄂尔多斯盆地西缘、南华北地区和阴山—燕山地区,面积较中侏罗世沉积明显缩小。上侏罗统以河流相沉积为主,碎屑岩,尤其是粗碎屑岩发育。早白垩世是晚三叠世以来沉积面积最大的时期,沉积区主要位于鄂尔多斯盆地、渤海湾盆地、胶莱盆地和南华北地区,以大型陆相湖泊沉积为主要特征,砂泥岩较发育。从岩相古地理角度分析,胶莱盆地和南华北地区周口盆地中部的谭庄—沈丘凹陷以及黄口、成武盆地是上侏罗统—下白垩统烃源岩形成的有利区,也应为油气形成的有利区。

The late Jurassic sedimentary area of North China platform is mainly located m the western ot the Erdos basin, southern North China and the Yinshan-Yanshan area, whose area significantly reduces, com- pared to the middle Jurassic sedimentary. The upper Jurassic sedimentary facies is mainly river facies, which is rich in clastic rock, especially coarse clastic rocks. The early Cretaceous sedimentary area is the largest since late Triassic, whose sedimentary is mainly located in Erdos basin, Bohai Bay basin, Jiaolai basin and the southern North China area, with the large continental lake sediment, and sand-mudstone develops in the lower Cretaceous. From the analysis of lithofacies palaeogeography, Jiaolai basin and Tanzhuang-Shenqiu sag and Huangkou, Chengwu basin of the southern North China area are favorable areas for the formation of hydro- carbon source rocks in the upper Jurassic-lower Cretaceous, which is possible favorable for the production of oil and gas.