FORMATION MECHANISM OF DEPRESSIONS AND RIFTS IN THE CENOZOIC BASIN OF NORTH JIANGSU PROVINCE

The Cenozoic Basin in North Jiangsu province consists of numerous depressions and rifts which develop on the Meso-Paleozoic thrust nappe and whose structure,size and regional distribution are controlled by the thrust nappe.The formation of rifts is the result of faultshards on the backedge of the thrust nappe backgliding under the background of regional extension which forms the "backedge sags" of the thrust nappe.In the North Jiangsu Basin,not only longitudinal rift-depression transformation exists in different periods,but also rifts and depressions coexist laterally in the same period.