Late Holocene Evolution of the Mekong Subaqueous Delta, Southern Vietnam

Xue, Zuo; Liu, Paul; Demaster, D. J.; Nguyen, Lap Van; Ta, Thi Kim Oanh

doi:10.1016/j.margeo.2009.12.005

Cited by 134 publications

(76 citation statements)

References 40 publications

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“…Shore-parallel shelf circulation near the channel mouths is weak and to the northeast during the summer, and is stronger and to the southwest during the winter [Gagliano and McIntire, 1968]. Net transport of sediment is to the southwest [Gagliano and McIntire, 1968] and has formed the Ca Mau peninsula and a shelf clinoform [Ta et al, 2005;Xue et al, 2010]. Despite sometimes energetic shelf conditions, waves within the distributary channels were minimal during our field campaigns.…”

Section: 1002/2015jc010754mentioning

confidence: 83%

Sediment dynamics in the lowerMekongRiver: Transition from tidal river to estuary

et al. 2015

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A better understanding of flow and sediment dynamics in the lowermost portions of large‐tropical rivers is essential to constraining estimates of worldwide sediment delivery to the ocean. Flow velocity, salinity, and suspended‐sediment concentration were measured for 25 h at three cross sections in the tidal Song Hau distributary of the Mekong River, Vietnam. Two campaigns took place during comparatively high‐seasonal and low‐seasonal discharge, and estuarine conditions varied dramatically between them. The system transitioned from a tidal river with ephemeral presence of a salt wedge during high flow to a partially mixed estuary during low flow. The changing freshwater input, sediment sources, and estuarine characteristics resulted in seaward sediment export during high flow and landward import during low flow. The Dinh An channel of the Song Hau distributary exported sediment to the coast at a rate of about 1 t s−1 during high flow and imported sediment in a spatially varying manner at approximately 0.3 t s−1 during low flow. Scaling these values results in a yearly Mekong sediment discharge estimate about 65% smaller than a generally accepted estimate of 110 Mt yr−1, although the limited temporal and spatial nature of this study implies a relatively high degree of uncertainty for the new estimate. Fluvial advection of sediment was primarily responsible for the high‐flow sediment export. Exchange‐flow and tidal processes, including local resuspension, were principally responsible for the low‐flow import. The resulting bed‐sediment grain size was coarser and more variable during high flow and finer during low, and the residual flow patterns support the maintenance of mid‐channel islands.

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Section: 1002/2015jc010754mentioning

confidence: 83%

Sediment dynamics in the lowerMekongRiver: Transition from tidal river to estuary

et al. 2015

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“…Modern muddy delta-scale subaqueous clinothems are characterized by shore-parallel, broad, low-angle cross-sectional profiles on wide (23-376 km) and gently-sloping (0.01-0.38°) shelves (Patruno et al, 2015a). Most of these clinoforms in the past were simply classified as "prodelta" (e.g., Roberts and Sydow, 2003), as they form muddy "subaqueous deltas" offshore major river outlets, usually developing a compound configuration (see later) with their subaerial delta counterparts (Driscoll and Karner, 1999;Swenson et al, 2005;Giosan et al, 2006a;Xue et al, 2010). Recent examples include the Ganges-Brahmaputra (Goodbred and Kuehl, 1999Kuehl et al, 1997Kuehl et al, , 2005Michels et al, 1998;Palamenghi et al, 2011, Fig.…”

Section: Delta Scale Clinoformsmentioning

confidence: 99%

Clinoforms and clinoform systems: Review and dynamic classification scheme for shorelines, subaqueous deltas, shelf edges and continental margins

Patruno

Helland‐Hansen

2018

Earth-Science Reviews

185

166

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A B S T R A C TClinoforms are inclined and normally basinward-dipping horizons developed over a range of spatial and temporal scales in both siliciclastic and carbonatic systems. The study of clinoform successions underpins sequence stratigraphy and all efforts to reconstruct the relative partitioning of reservoir, seal and source rocks along shoreline to basin-floor profiles.Here, we review clinoform research and propose a more systematic description and classification of clinoforms. This is a crucial step to improve predictions of facies and lithology distribution within shoreline to continental shelf and abyssal plain successions, together with the genesis, drivers and dynamics of their constituent sedimentary units.Four basic clinoform types are here distinguished in delta/shorelines, lacustrines and marine environments, on the basis of their overall spatial and temporal scale, morphology, outbuilding dynamic and geodynamic and depositional setting: (1, 2) delta-scale clinoforms, which in turns are sub-divided into shoreline and delta-scale subaqueous clinoforms; (3) shelf-edge clinoforms; and (4) continental-margin clinoforms. Delta-scale clinoform sets are tens of metres high and typically represent 1-10 3 kyr, with progradation rates ranging from 1,000-100,000 m/kyr for shorelines and "subaerial deltas" to 100-20,000 m/kyr for subaqueous deltas; shelfedge clinoform sets are hundreds of metres high and are nucleated and accreted in 0.1-20 Myr (usual progradation rates of 1-100 m/kyr) by successive cross-shelf transits of delta-scale clinoforms; continental-margin clinoform sets are thousands of metres high, hallmark key geodynamic/crustal boundaries (e.g., continent/ocean transition) and slowly prograde basinwards in ca. 5-100 Myr, with typical rates of 0.1-10 m/kyr. As a consequence of the very different progradation rates and of the difficulty of large-scale clinothems to backstep during transgressions, shorelines are the most dynamic clinoforms with regards to position, continental margins the least, and shelf-edges are intermediate. Shortly after a transgression, therefore, the four clinoform types may prograde synchronously along shoreline-to-abyssal plain transects, forming "compound clinoform" systems. During the subsequent regressive cycle, however, due to the dissimilarity in progradation rates, different clinoform types will normally merge progressively with each other, giving rise to "hybrid clinoforms" (e.g., shelf-edge deltas), and fewer depositional breaks-in-slope are distinguished along a single shoreline-toabyssal plain transect. Overall, all clinoform systems are the result of the dynamic evolution of compound and hybrid clinoforms along a temporal and spatial continuum, regulated by the cyclical backstepping of the smallerscale system within natural progradational-retrogradational cycles of larger-scale clinothem outbuilding.All clinothem types may show either an accretionary/active or draping/passive style, depending on the proximity to the sediment source. Draping clinothems are nearly...

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“…This proportion quantifies the summed deposition of total nitrogen, total phosphor, total potassium and total organic carbon. Finally, the sediment deposition depth is calculated from the cumulative sedimentation rate and the 1.2 t m −3 dry bulk density of sediment soil in the MD specified in Xue et al (2010). A comparison of simulated sedimentation with measured data in 2011 (Manh et al, 2013(Hung et al, 2013b) is shown in Fig.…”

Section: Sedimentation and Nutrient Deposition In The Vmd Floodplainsmentioning

confidence: 99%

Large-scale suspended sediment transport and sediment deposition in the Mekong Delta

Manh

Dũng

Hung

et al. 2014

Hydrol. Earth Syst. Sci.

102

123

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Abstract. Sediment dynamics play a major role in the agricultural and fishery productivity of the Mekong Delta. However, the understanding of sediment dynamics in the delta, one of the most complex river deltas in the world, is very limited. This is a consequence of its large extent, the intricate system of rivers, channels and floodplains, and the scarcity of observations. This study quantifies, for the first time, the suspended sediment transport and sediment deposition in the whole Mekong Delta. To this end, a quasi-2D hydrodynamic model is combined with a cohesive sediment transport model. The combined model is calibrated using six objective functions to represent the different aspects of the hydraulic and sediment transport components. The model is calibrated for the extreme flood season in 2011 and shows good performance for 2 validation years with very different flood characteristics. It is shown how sediment transport and sediment deposition is differentiated from Kratie at the entrance of the delta on its way to the coast. The main factors influencing the spatial sediment dynamics are the river and channel system, dike rings, sluice gate operations, the magnitude of the floods, and tidal influences. The superposition of these factors leads to high spatial variability of sediment transport, in particular in the Vietnamese floodplains. Depending on the flood magnitude, annual sediment loads reaching the coast vary from 48 to 60 % of the sediment load at Kratie. Deposited sediment varies from 19 to 23 % of the annual load at Kratie in Cambodian floodplains, and from 1 to 6 % in the compartmented and diked floodplains in Vietnam. Annual deposited nutrients (N, P, K), which are associated with the sediment deposition, provide on average more than 50 % of mineral fertilizers typically applied for rice crops in non-flooded ring dike floodplains in Vietnam.Through the quantification of sediment and related nutrient input, the presented study provides a quantitative basis for estimating the benefits of annual Mekong floods for agriculture and fishery, and is an important piece of information with regard to the assessment of the impacts of deltaic subsidence and climate-change-related sea level rise on delta morphology.

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Late Holocene Evolution of the Mekong Subaqueous Delta, Southern Vietnam

Cited by 134 publications

References 40 publications

Sediment dynamics in the lowerMekongRiver: Transition from tidal river to estuary

Sediment dynamics in the lowerMekongRiver: Transition from tidal river to estuary

Clinoforms and clinoform systems: Review and dynamic classification scheme for shorelines, subaqueous deltas, shelf edges and continental margins

Large-scale suspended sediment transport and sediment deposition in the Mekong Delta

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