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