Modern sedimentation and sediment dispersal pattern on the continental shelf off the Mekong River delta, South China Sea

Szczuciński, Witold; Jagodziński, Robert; Hanebuth, Till J J; Stattegger, Karl; Wetzel, Andreas; Mitręga, Marta; Unverricht, Daniel; Phách, Phùng Văn

doi:10.1016/j.gloplacha.2013.08.019

Cited by 65 publications

(32 citation statements)

References 71 publications

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“…Semi-diurnal lunar tide M2 and solar tide S2 amplitudes are up to 0.9 m and 0.5, respectively, while diurnal solar tide K1 and lunar tide O1 amplitudes are up to 0.7 m and 0.5 m, respectively, along the MRD [41]. The resulting amplitude is gradually decreasing from 3.8 m in the Northeast (NE) area to approximately 2 m in the Southwest (SW) along the Ca Mau peninsula [26].…”

Section: Tidesmentioning

confidence: 99%

Numerical Simulations of Suspended Sediment Dynamics Due to Seasonal Forcing in the Mekong Coastal Area

Vinh¹,

Ouillon

Thao³

et al. 2016

Water

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Abstract:The Mekong River is ranked as the 8th in terms of water discharge and as the 10th in terms of sediment load in the world. During the last 4500 years, its delta prograded more than 250 km to the south due to a tremendous amount of sediments deposited, and turned from a "tide-dominated" delta into a "wave-and-tide dominated" delta. This study aims at completing our knowledge on the fate of sediments that may be stored in estuarine or coastal systems, or dispersed over the continental shelf and slope. Sediment transport in the Mekong River Delta (MRD) coastal area was studied by numerical simulations using the Delft3D model. The model configuration was calibrated and validated from data collected in situ during 4 periods from 2012 to 2014. Then, 50 scenarios corresponding to different wave conditions (derived from the wave climate) and river discharge values typical of low flow and flood seasons enabled us to quantify the dispersal patterns of fluvial sediments close to the mouths and along the coast. Sediments mostly settled in the estuary and close to the mouths under calm conditions, and suspended sediment with higher concentrations extend further offshore with higher waves. Waves from the Southeast enhanced the concentration all along the MRD coastal zone. Waves from the South and Southwest induced coastal erosion, higher suspended sediment concentrations in front of the southern delta, and a net transport towards the Northeast of the delta. Because of episodes of Southern and Southwestern waves during the low flow season, the net alongshore suspended sediment transport is oriented Northeastward and decreases from the Southwestern part of the coastal zone (~960ˆ10 3 t yr´1) to the Northeastern part (~650ˆ10 3 t yr´1).

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Section: Tidesmentioning

confidence: 99%

Numerical Simulations of Suspended Sediment Dynamics Due to Seasonal Forcing in the Mekong Coastal Area

Vinh¹,

Ouillon

Thao³

et al. 2016

Water

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“…In very dry sediments, smallscale variability of moisture content tends to be the lowest; it increases gradually with the amount of moisture, but it starts to drop and reaches the lowest values in very wet sediments (Edwards, 2013). Previous studies reported spatial variability with respect to both organic matter (Szczuciński et al, 2013;Yuan et al, 2014) and pH (Diab et al, 2014;Yuan et al, 2014) for sediments along the deposition areas.…”

mentioning

confidence: 99%

Physical and chemical properties of recently deposited sediments in the reservoir of the Borçka Dam in Artvin, Turkey

Turgut¹,

Özalp²,

Köse³

2015

Turk J Agric For

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IntroductionSediment is described as solid particles generated by the disintegration process of organic and inorganic materials (Bortone, 2006). These particles, found in various shapes and sizes, can be transported by water, wind, glaciers, and other natural causes (Montgomery et al., 2000). Sediment deposited in deltas and reservoirs are generally fine-grained (sand, silt, and clay) (Kamarudin et al., 2009;Tigrek and Aras, 2011). The sedimentation process depends on the flow regime and flow rate of the river (Kamarudin et al., 2009). Natural rivers are considered balanced with respect to sediment and water inflow and outflow. However, when rivers are controlled, especially by the construction of large dams, this balance can be dramatically changed (Morris and Fan, 1998). The alteration of the natural flow regime leads to changes to the hydrological, geomorphological, and ecological conditions both upstream and downstream (Galay, 1983;Graf, 2006;Magilligan et al., 2013;Csiki and Rhoads, 2014;. Dam construction in rivers decreases velocity, causing a sedimentation increase upstream of the dam. This reduces the storage capacity of reservoirs, thus negatively influencing other benefits of large dams, such as water supply, power production, and flood control (Morris and Fan, 1998). Sedimentation can change geomorphological conditions upstream of reservoir areas. For example, sediments deposited along riverbanks due to reduced flow will narrow the cross-section of a river before it reaches the reservoir, while the accumulated sediments can change the terrain of the bottom of the reservoir (Ryan, 1991;Csiki and Rhoads, 2014). Changes in the amount and composition of sediment, carrying

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“…These sediments are delivered to the continental shelf, which is wide along the northwestern margin of the SCS, narrow off Central Vietnam, and wide again at the shallow Sunda shelf in the south (J. Liu et al, 2010;Hanebuth et al, 2011;Sathiamurthy & Voris, 2006;Szczuciński et al, 2009Szczuciński et al, , 2013Yao et al, 2009).…”

Section: Climatic Oceanic and Sedimentary Contextmentioning

confidence: 99%

Magnetic Fingerprints of Modern Sediments in the South China Sea Resulting From Source‐to‐Sink Processes

Kissel

Sarnthein²,

Làj

et al. 2018

Geochem Geophys Geosyst

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More than 650 Mt/year of fluvial sediment are delivered from continental regions into the South China Sea (SCS). Previous studies have shown that the composition of the magnetic fraction of riverine sediments drained into the SCS is significantly variable from north to south. On the basis of this evidence, we now examine a full set of magnetic properties for a number of core tops taken at water depth of mostly between 800 and 3,500 m. Room temperature magnetic parameters and thermal spectra are used to obtain information about the concentration and mineralogical magnetic composition. Spatial changes are observed in the relative proportion of magnetite and hematite with an increase of the latter toward the south, similarly to the observation on land. However, the N‐S contrast is much weaker in marine core tops than in river sediments, because of the role played by the shelf in partly trapping river‐borne sediments, in particular in the southern SCS. In part, sediments also reach the continental slope and the deep basins, being transported and mixed by surface and deepwater currents, which yield the magnetite‐hematite mixing in the south. For the first time, we characterize a wide spectrum of magnetic properties of modern marine sediment in the SCS. Our results give important insights into the modern pathways of sediment particles, depicting the source‐to‐sink processes that affect the terrigenous sediment load.

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Modern sedimentation and sediment dispersal pattern on the continental shelf off the Mekong River delta, South China Sea

Cited by 65 publications

References 71 publications

Numerical Simulations of Suspended Sediment Dynamics Due to Seasonal Forcing in the Mekong Coastal Area

Numerical Simulations of Suspended Sediment Dynamics Due to Seasonal Forcing in the Mekong Coastal Area

Physical and chemical properties of recently deposited sediments in the reservoir of the Borçka Dam in Artvin, Turkey

Magnetic Fingerprints of Modern Sediments in the South China Sea Resulting From Source‐to‐Sink Processes

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