Sedimentary evolution of the Central Canyon System in the Qiongdongnan Basin, northern South China Sea

This study elucidates sedimentary evolution history of the Central Canyon System(CCS),a large axial submarine canyon in the Qiongdongnan Basin(QDNB),northern South China Sea.Thegeomorphological characteristics and infill architectures of the CCS are summarized based on theanalysis of two-and three-dimensional seismic data.Based on a comparative analysis of the CCS indifferent segments and evolutionary stages and in consideration of the tectono-sedimentary conditionsof the QDNB four stages of the sedimentary evolution of the CCS can be divided,i.e.initialdevelopment stage in the Late Miocene(11.6-5.7Ma),erosion-infilling stage in the Early Pliocene(5.7-3.7 Ma),tranquil infilling stage in the Late Pliocene(3.7-1.81 Ma),and rejuvenation stage sincethe Pleistocene(1.81 Ma to present).In the 1ate Middle Miocene(~11.6 Ma),the rudiment of CCswas developed by a regional tectonic transformation in the eastern part of the basin.In the EarlyPliocene,the CCS was further developed from west to east and restrained in the central depressionbelt of the basin due to abundant sediment supplies from the northwestern and northem provenances,the blocking effect of the southern uplift belt,and the restrictive geomorphological features of theeastern part of the basin.In the Late Pliocene,changes in the sedimentary environment resulted in thedevelopment of the CCS in the eastern part of the basin only.Since the Pleistocene,the joint action ofclimatic factors and geomorphological features of the eastern part of the basin led to the rejuvenationof the CCS.