Seismic characteristics and processes of the Plio-Quaternary unidirectionally migrating channels and contourites in the northern slope of the South China Sea
Highlights
► Distributions of unidirectionally migrating channels and contourites had been studied. ► Circulations of intermediate and deep water contour current had been improved. ► Process of migrating channels and drifts had been worked.
Introduction
Gravity flow channels and contour current deposits are commonly developed on slopes. The channels are U- or V-shaped and include thalweg, levee, and slump deposits. These deposits are controlled by sediment supply, morphology, slope gradient, tectonic movement, and so on (Antobreh and Krastel, 2006; Armitage et al., 2009; Bertoni and Cartwright, 2005; Cunningham et al., 2005; Jobe et al., 2011; Lastras et al., 2009; Mountjoy et al., 2009; Shepard, 1981; Shepard and Emery, 1973; Weaver et al., 2000). The erosion and deposition of turbidity current and debris flow may contribute to the formation of channels (Shepard, 1981; Weaver et al., 2000). An increasing number of migrating channels attributed to the interaction between gravity flow and contour current has also been reported in West Africa, Brazil, and so on (Biscara et al., 2010; Rasmussen, 1994, 2003; Séranne and Abeign, 1999; Viana et al., 1999; Zhu et al., 2010). Fortunately, a series of NE- and WSW-migrational channels have developed in the northern slope of the South China Sea (SCS) (He et al., 2012; Zhu et al., 2010). However, studies on the genesis of these channels are limited (He et al., 2012; Zhu et al., 2010).
Contourites can reach kilometers of thickness and cover huge area (Faugères et al., 1993; Rebesco and Camerlenghi, 2008). Previous works have concentrated on bedforms, flow directions, frameworks, variability, and so on (Faugères et al., 1993, 1999; Hollister and Heezen, 1972; Kenyon and Belderson, 1973; Masson et al., 2004; Rebesco and Camerlenghi, 2008; Rebesco and Stow, 2001; Wynn and Stow, 2002). Plio-Quaternary contourites are well developed in the northern slope of the SCS (Lüdmann et al., 2005; Shao et al., 2001, 2007; Wang et al., 2010; Zhu et al., 2010; Gong et al., 2012). Accordingly, the present study investigated slope areas of the SCS near Dongsha Islands. Focus was given on the significant issue of the distribution of contourites in the northern slope of the SCS. This study also aimed to 1) summarize the seismic features of unidirectionally migrating channels (UMCs) and contourites, 2) examine the distribution of UMCs and contourites, 3) analyze the processes of UMCs and drifts, and 4) improve contour current circulation models.
Section snippets
Geological setting
The SCS, located in the Asian continent and surrounded by Indochina, Kalimantan Island, the Philippine Islands, and Taiwan Island, is a semi-enclosed deep water basin. The SCS has an area of 3.5 × 106 km2 and is more than 5000 m deep, trending northeast. The Luzon strait (300 km wide and 2500 km deep) is the main channel that connects the SCS with the Pacific Ocean (Li, 2002; Zhu et al., 2010). The SCS is the largest marginal sea in the west Pacific Ocean and is located in the southeastern
Data and methods
This study was based on two-dimensional (2D) and three-dimensional (3D) seismic data provided by the China National Offshore Oil Corporation Research Institute. The 2D seismic profiles covered almost the entire study area with water depths of approximately 200 m–3000 m in the PRMB and QDNB, northern SCS, as shown in Figure 2. The study profiles consist of NW–SE and NE–SW seismic profiles. The space of NW–SE and NE–SW profiles are 400 and 250 m, respectively. Sampling rate is 2 ms and group
Unidirectionally migrating channels (UMCs)
Two kinds of UMCs are found in the northern slope of the SCS. The first kind is developed at water depths of approximately 200 m–1200 m with NE migration. The second one is distributed at water depths of >1200 m, with WSW migration.
NE-migrating channels are developed in southeastern Hainan Island, Baiyun, Liwan1, and Dongsha Islands at water depths of 200 m–1500 m. Most of them orientate N–S, oblique to the slope. These channels are U or V shaped, indicating obvious migrational characteristics,
Processes of UMCs
The UMCs had been reported in Gabon (West Africa), Campos Basin (Brazil), and northern slope of the SCS (Biscara et al., 2010; He et al., 2012; Mulder et al., 2008; Rasmussen, 1994, 2003; Séranne and Abeign, 1999; Viana et al., 1998, 1999; Zhu et al., 2010). These UMCs probably result from the interaction between gravity flow and contour current (He et al., 2012; Rasmussen et al., 2003; Zhu et al., 2010).
On one hand, the sediment supply is able to influence the channel location. UMCs are
Conclusions
In this paper, a series of Plio-Quaternary channels and contourites are studied based on seismic data in the northern slope of the SCS. A number of points are determined as follows:
- (1)
Plio-Quaternary NE- and WSW-migrating channels, as well as contourites are developed. Unidirectionally migrating channels result from the interaction between gravity flows and contour currents, where channels migrate in the direction of contour current flow. The contourites include giant elongated, confined, and
Acknowledgments
This work was supported by the National Basic Research Program of China (NO. 2009CB219407) and the National Natural Science Foundation of China (NO. 40972077). We gratefully acknowledge the CNOOC Research Institute for providing the seismic data. We would like to thank Thomas Hadlari, Michele Rebesco, Doctor Chenglin Gong, Pin Yan, Qiliang Sun and anonymous reviewers for their fruitful suggestions.
References (63)
- et al.
Morphology, seismic characteristics and development of Cap Timiris Canyon, offshore Mauritania: a newly discovered canyon preserved-off a major arid climatic region
Marine and Petroleum Geology
(2006) - et al.
Deep water ventilation in the South China Sea
Deep Sea Research, Part I
(1996) - et al.
An evaluation of along- and down-slope sediment transport processes between Goban Spur and Brenot Spur on the Celtic margin of the Bay of Biscay
Sedimentary Geology
(2005) - et al.
Contourite drift types and their distribution in the North and South Atlantic Ocean basin
Sedimentary Geology
(1993) - et al.
Seismic features diagnostic of contourite drifts
Marine Geology
(1999) - et al.
Mudwaves in the Argentine Basin and their relationship to regional bottom circulation patterns
Deep-sea Research
(1988) - et al.
Contourite erosive features caused by the Mediterranean outflow water in the Gulf of Cadiz: Quaternary tectonic and oceanographic implications
Marine Geology
(2009) - et al.
Sediment waves on the South China Sea slope off southwestern Taiwan: implications for the intrusion of the northern pacific deep water into the South China Sea
Marine and Petroleum Geology
(2012) - et al.
Ferromanganese nodules and micro-hardgrounds associated with the Cadiz Contourite Channel (NE Atlantic): palaeoenvironmental records of fluid venting and bottom currents
Marine Geology
(2012) - et al.
The contourite depositional system of the Gulf of Cadiz: a sedimentary model related to the bottom current activity of the Mediterranean outflow water and its interaction with the continental margin
Deep-sea Research II
(2006)
Sensitive grain-size records of Holocene East Asian summer monsoon in sediments of northern South China Sea
Quaternary Research
Two fundamentally different types of submarine canyons along the continental margin of Equatorial Guinea
Marine and Petroleum Geology
Bedforms of the Mediterranean undercurrent observed with sidescan sonar
Sedimentary Geology
Geomorphology and sedimentary features in the Central Portuguese submarine canyons, Western Iberian margin
Geomorphology
Plio-Quaternary sedimentation process and neotectonics of the northern continental margin of the South China Sea
Marine Geology
Structure and evolution of the “Olistostrome” complex of the Gibraltar Arc in the Gulf of Cadiz (eastern central Atlantic): evidence from two long seismic cross-sections
Marine Geology
Morphostructure and evolution of submarine canyons across an active margin: Cook Strait sector of the Hikurangi Margin, New Zealand
Marine Geology
Mixed turbidite-contourite systems
Post-Eocene seismic stratigraphy of the deep ocean basin adjacent to the southeast African continental margin: a record of geostrophic bottom current systems
Marine Geology
The relationship between submarine canyon fill and sea level change: an example from middle Miocene offshore Gabon, West Africa
Sedimentary Geology
Oligocene to Holocene sediment drifts and bottom currents on the slope of Gabon continental margin (west Africa) consequences for sedimentation and southeast Atlantic upwelling
Sedimentary Geology
Bottom-current controlled sand deposits – a review from modern shallow to deep water environments
Sedimentary Geology
Classification and characterisation of deep-water sediment waves
Marine Geology
Characteristics of migrating submarine canyons from the middle Miocene to present: implications for paleoceanographic circulation, northern South China Sea
Marine and Petroleum Geology
The influence of mass-transport-deposit surface topography on the evolution of turbidite architecture: the Sierra Contreras, Tres Pasos Formation (Cretaceous), Southern Chile
Journal of Sedimentary Research
3D seismic analysis of slope-confined canyons from the Plio-Pleistocene of the Ebro Continental Margin (Western Mediterranean)
Basin Research
Migrating submarine furrows on Gabonese margin (West Africa) from Miocene to present: influence of bottom current?
Geo-temas
Tracing tropical and intermediate waters from the South China Sea to the Okinawa Trough and beyond
Journal of Geophysical Research
A study of the water exchange between Pacific Ocean and the South China Sea
Acta Oceanography Taiwanica
A survey of studies on the South China Sea upper ocean circulation
Acta Oceanography Taiwanica
Contourite drifts: nature, evolution and controls
Cited by (87)
Geomorphologic and infilling characteristics of the shelf-incising submarine canyon in the eastern Makran accretionary prism, offshore Pakistan
2024, Journal of Asian Earth SciencesSlope instability and submarine-moat initiation: Insights from the northern South China sea margin
2024, Marine and Petroleum GeologySand-rich Pleistocene deep-water channels and their implications for gas hydrate accumulation: Evidence from the Qiongdongnan Basin, northern South China Sea
2023, Deep-Sea Research Part I: Oceanographic Research PapersArchitecture, controlling factors and evolution history of unidirectionally upstream-migrating turbidite channels: A case study from southern Qiongdongnan Basin, northern South China Sea
2022, Marine and Petroleum GeologyCitation Excerpt :They are mainly divided into two types according to their migration directions downstream and upstream of contour currents: unidirectionally downstream-migrating turbidite channels (UDMTCs) and unidirectionally upstream-migrating turbidite channels (UUMTCs). The former migrate towards the downstream of (paleo) contour current direction (Zhu et al., 2010; Gong et al., 2013, 2016a, 2018; He et al., 2013; Li et al., 2013), and the latter migrate towards upstream (Chen et al., 2020; Fonnesu et al., 2020; Lu et al., 2021; Miramontes et al., 2021). UDMTCs are markedly characterized by the lack of (internal) levees, and various materials of turbidity flows are predominantly deposited within the interior of canyons and are the absence of overspill deposits (Li et al., 2018; Gong et al., 2020).