Sedimentary Facies of Mingyuefeng Formation in Oujiang Sag,East China Sea Basin

By means of cores description,well log,logging,paleontology,heavy minerals,and seismic facies,we elucidate the material source of Mingyuefeng Formation in the Oujiang sag,and then comprehensively discuss sedimentary facies and its features,based on structural evolution and relative sea level change.At late Paleocene Mingyuefeng Phase,the Oujiang sag experienced the fault switching sag,the source sediments were transported from two sides of sag,the main source was Mingzhe structural belt in the western sag,and the second was Yandang low bump in the eastern.When the large-scale transgression at middle and later Palaeocene caused the relative sea level rising,the Yandang low bump started accept the sediments and reached the biggest sedimentary area.The sedimentary facies of the sag are representative of seashore and shallow sea,with the abundance of sediment supply from the Mingzhe structural belt.Three large-scale delta sediments were formed at the western slope of sag,where the seashore sediment lie at the margin of sag,and the shallow sea sediment was located in the centre of sag.The distribution of sedimentary facies is mainly controlled by structure and the of relative sea level change,especially the later.