华北地台区早-中侏罗世岩相古地理特征

Lithofacies Paleogeographic Characteristics of Early-middle Jurassic in North China Platform

依据地层多重划分对比原理,建立了华北地台区下-中侏罗统的地层划分对比格架,并分别编制了早、中侏罗世岩相古地理图。由于印支运动末期华北地台区整体抬升,下侏罗统的沉积范围与上三叠统相比明显缩小。中侏罗统在华北地台区沉积范围较下侏罗统明显加大,除鄂尔多斯盆地、南华北地区外,在渤海湾盆地也出现较多的中侏罗统沉积。下侏罗统的沉积中心位于鄂尔多斯盆地东北部,中侏罗统在鄂尔多斯盆地沉积范围较下侏罗统明显扩大,沉积中心逐渐向西北方向迁移。南华北地区下侏罗统沉积区主要分布于合肥盆地和济源盆地,中侏罗统在南华北地区的沉积盆地增多,除合肥盆地、济源盆地外,在黄口、周口、义马等盆地也发育了部分沉积,并且均受到北东向和北西向断裂的联合控制。在渤海湾盆地下侏罗统仅北部有少量沉积,中侏罗统盆地分布范围明显扩大,济阳坳陷区、临清坳陷区、黄骅坳陷区均出现了大面积的沉积区。

According to the principle of multiple stratigraphic division and correlation,framework was established for stratigraphic division and correlation of lower-middle Jurassic in the North China platform,and lithofacies paleogeographic maps of early and middle Jurassic were drawn respectively.Compared with upper Triassic,the lower Jurassic sedimentary range reduced significantly during the uplifting of North China Platform as a whole at the end of indosinian movement.Compared to the lower Jurassic in the area of North China platform,the middle Jurassic sedimentary range increased remarkably,except for Ordos Basin and Southern North China,there were many middle jurassic sediments in the Bohai Bay Basin.The sedimentary center was located in the northeast of Ordos Basin during Early Jurassic.The middle Jurassic sedimentary rang was larger than that of the early Jurassic,and the sedimentary center was gradually migrated to the northwest of Ordos Basin.The sedimentary of Early Jurassic in the Southern North China was mainly distributed in Hefei Basin and Jiyuan Basin,but sedimentary range increased in the middle Jurassic,in addition to Hefei Basin and Jiyuan Basin,part of depositions were also developed in Huangkou,Zhoukou and Yima Basins,which were controlled by the fractures from northeast and northwest.There are a small amount of deposits of lower Jurassic in the North of Bohai Bay Basin,but sedimentary range increases obviously in the middle Jurassic,a large area of sedimentary basins occurs in Jiyang,Linqing and Huanghua Depressions in Bohai Bay Basin.