Sedimentary Features of Shallow Ancient River Channels on the Northern Shelf of the South China Sea1

Abstract

Abstract Quaternary buried ancient river channels are widespread in the shallow‐level sediments of the northern shelf of the South China Sea. The sedimentary sequence mainly of fluvial deposits comprise an important component part of the low‐stand system tract and transgressive system tract in the study region. The plannar variation and spatial association of the sedimentary features such as incised valley fillings, deltaic foreset wedges and block slides of shelf‐marginal fans reflect the palaeogeographic environment during the fall of the regional sea level in the northern part of the South China Sea. Based on the high‐resolution seismic reflection data and gelogical data from boreholes, the present paper makes an integrated interpretation of the Quaternary ancient river channels in the shallow sediments of the study area, studies the sedimentary features of the ancient channels such as their spatial distribution, seismic facies reflection indicators, sedimentary facies and sand‐body types, and discusses their formational setting and evolutionary model, with the main purpose to render a service to the hydrocarbon resources exploration and development and marine engineering in the northern shelf of the South China Sea.