Abstract:

It has been considered for a long time that differences in sedimentation had existed between the eastern and the western parts in the North China faultblock region since the Trassic,i.e. there was an isolated sedimentary basin in the west (Ordos),and a large uplift with only a few small basins in the east.According to data collected recently from geological and seismic prospecting,the author suggests that as early as Trassic,there existed a entire large sedimentary basin at least ranging from the western edge of Ordos to the southern part of the North China plain. Sediments in this area are similar to those of upper Paleozoic,which are differentiation in the north and south. During the Middle Jurassic,the basin reduced and disintegrated,the south and north edges of the North China fault-block region as well as both the north and middle segments of Taihang Mountains uplifted. It was not until the Early Cretaceous that Ordos basin formed.Seismic prospecting has revealed that the sediments greater than 6000m of Mesozoic and upper Palcozoic have bccn found in the southward of Shijiazhuang-Dezhou region. This has also been proved by drilling,and the thickness of Mesozoic sediments may greater than that in southern Ordos and Jiyuan areas. So it is predicted that they might be well promissing to oil and gas.