Abstract: The recent exploration for oil and gas in deep water has revealed that the distribution of submarine fans is complex in thrust fault zone on continental slope.While the influences of thrusting related topography on macroscopic distribution of submarine fans have been studied both at home and abroad,few researches have been carried out in terms of its distribution and evolution at different stages of thrusting.This paper studied the distribution pattern of submarine fans in the thrust fault zone on continental slope in a deep-water zone of the Niger Delta Basin,utilizing well-logging and seismic data.Results show that the Upper Miocene-Quaternary, the target in the study area,is divided into nine third-order sequences according to stratigraphic overlap and sea level variation,and three types of submarine fan depositional units(massive transport,channel and lobe deposits) are identified.Vertically,the submarine fans are mainly located in the re-trogressive system tracts(RST) of each third-order sequence,while laterally,they present complex evolution and distribution patterns due to the control of differential palaeogeomorphology at different stages of thrusting.In the study area,the submarine fans have evolved through four stages.The first one is equilibrium slope stage.As few thrust faults were active and the slope was relatively gentle in geomorphology at this stage,thrusting delivered little control to the submarine fans.And the submarine fan system was developed in the central part of the study area and was dominated by sinuous stripe-shaped channels.The second one is thrusting stage.The vigorous activity of thrust faults into the deep water triggered the formation of minibasins on the hanging walls of thrust faults;thus the transportation of gravity flow was prevented,and large composite lobes, linked with each other,occurred.The third one is mud diapire stage.The thrust fault activity slowed down and upward mud diapirism occurred in its core during this stage.Then the mud diapire anticline developed in the central part of the study area,while minibasins along the direction of continental slope grew on the east and west sides of the anticline.Plenty of gravity flow sediments bypassed these longitudinal minibasins,forming the submarine fan channel-lobe complexes that differentiated in east-west direction.The fourth one is sedimentation-dominant stage.As the thrusting in the study area almost stopped,the continental slope gradually turned to equilibrium and stripe-shaped channel deposits with low sinuosity were developed quite even in the whole area.

Key words: geomorphology, thrust fault, submarine fan, sedimentary evolution, Niger Delta Basin, West Africa