Depositional architecture and developing settings of large-scale incised valley and submarine gravity flow systems in the Yinggehai and Qiongdongnan basins, South China Sea

Abstract

In the Ying-Qiong basins in the South China Sea developed a set of giant inner shelf slope and submarine gravity flow deposits in the Ying-Huang formations since the Late Miocene. These deposits can be classified into 9 sequences in which slope slump-debris flow, slope fan and particularly, the large-scale axial basin-floor incised valley fills have been recognized. They were distributed in a distinctive pattern attributed to tectonic control. The development of shelf slopes and abyssal plains in the basins was related to the last episode of rapid subsidence and a large amount of sediment inputs. Large-scale basin-floor incised valleys, formed during the late Miocene and Pliocene, indicate several major sea level falls that occurred in the South China Sea.