THE DISCOVERY AND SIGNIFICANCE OF NAPPE STRUCTURE FORMED IN THE INDO EARLY YANSHAN MOVEMENT IN THE BASEMENT OF HUANGHUA DOWN WARPED BASIN

Nappe structure formed in the Indo early Yanshan movement were found in the north,the south and the inner platform fold belts of the North China platform.But it is not in document so far in the basement of the vast east basin of the platform.Based on the interpretation of seismic sections and the examination of core,the nappe structure form was discerned in the Kongxi buried hill in the Huanghua down warped basin.Typical elements of nappe structure,such as fault slope,fault flat,antithetic thrust,overlap beds,and so on,were found in the buried hill.As to the driving force of the nappe structure,the left slip motion of the Tanlu fault zone during the Indo early Yanshan movement was proposed.The confirmation of the nappe structure in the basement of the Huanghua basin may have implications to the further oil and gas exploration in that area.