RESEARCH ON MOLDING, STRUCTURAL FEATURE AND FORMATION MECHANISM OF THE CENTRAL UPLIFT BELT IN DONGYING DEPRESSION,JIYANG

The central uplift belt is an oil/gas enrichment zone in the Dongying depression of jiyang geotectogene.It trends nearly E-W and is a dissymmetrical anticline belt with steep dip angle in the north limb and gentle in the south.A rift-fault system of cabbage style develops on the uplift belt.Because of the characteristics of synsedimentary and reverse drag controlled by the north boundary fault.It was considered as a roll anticline belt in the early exploration time.Due to the accumulation of geological and geophysical data,most of the following investigators have argued the origin of salt-mud diapir structure since 80's.Based on detailed studying of sesimic and geological data and comparing to previous research results,a sadbox experiment is designed and carried through in this work to search the cause of the central uplift belt.By all the results above,we conclude that the Dongying central uplift belt was formed by extention-diapirism lead by regional tenso-shear stress and gravity,and the shape of the local auticlines and the character of the fault system are controlled by the shape of the salt-mud diapir and the intensity of extension and diapirism.