--> Morphology, Seismic Characteristics and Origin of Widespread Sediment Waves in a Submarine Canyon System on the Northern South China Sea Margin

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Morphology, Seismic Characteristics and Origin of Widespread Sediment Waves in a Submarine Canyon System on the Northern South China Sea Margin

Fuliang Lyu1, Wei Li2, Jian Li2, Li Li1, Jingwu Wu1


1Petrochina Hangzhou Research Institute of Geology;
2Institute of Oceanology, Chinese Academy of Sciences


May 19-22 2019 – 2019 AAPG Annual Convention and Exhibition, San Antonio, Texas

Posted: June 30, 2019

Abstract

High-resolution multibeam bathymetric and 2D seismic data are used to investigate the morphology, internal architecture and origin of widespread sediment waves in the eastern area of a submarine canyon system on the northern South China Sea margin. These sediment waves exhibit quite similar seafloor morphologies and their crests are parallel or sub-parallel to the bathymetric contours. The seismic characteristics of these sediment waves show several differences. Three types of sediment waves (Type A, B and C) can be classified on the basis of their locations and internal characters. Type A and B sediment waves are mainly discovered in the canyon ridges and the sediment waves of Type C are located in the canyon head areas. The seismic reflections within Type A and C sediment waves are continuous and they all have an upslope migrating trend, while the individual sediment waves of Type B are separated by listric faults. A key result of our analysis is the origin and implications of the three different types of sediment waves. The Type A sediment waves are inferred to be formed by turbidity currents flowing through the submarine canyons and overflowing the canyon flanks. Gravity-driven submarine creeping may result in the formation of Type B sediment waves. The Type C sediment waves are suggested to be generated by internal waves interacting with the continental slope. The internal waves might be sourced from the Luzon Strait as reported in previous oceanographic studies. Our results may enable the better understanding of the origin of widespread sediment waves on other submarine canyon systems. It would be also of great significance for a correct risk assessment, as our study area now is one of the most active regions for hydrocarbon explorations.

AAPG Datapages/Search and Discovery Article #90350 © 2019 AAPG Annual Convention and Exhibition, San Antonio, Texas, May 19-22, 2019