A water and sediment budget for the lower Mississippi–Atchafalaya River in flood years 2008–2010: Implications for sediment discharge to the oceans and coastal restoration in Louisiana

Allison, Mead A.; Demas, Charles R.; Ebersole, Bruce A.; Kleiss, Barbara A.; Little, Charles D.; Meselhe, E. A.; Powell, Nancy J.; Pratt, Thad C.; Vosburg, Brian M.

doi:10.1016/j.jhydrol.2012.02.020

Cited by 253 publications

(211 citation statements)

References 37 publications

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“…1) are the largest rivers in North America and Asia, respectively. Their geological and hydrological conditions and geomorphological evolution have previously been reported for the Mississippi River (Meade et al, 1995;Colman et al, 1998;Roberts, 1998;Day et al, 2007;Bianchi & Allison, 2009;Blum & Roberts, 2009;Horowitz, 2009;Meade & Moody, 2010;Allison et al, 2012) and the Yangtze River (Chen et al, 2001;Yang et al, 2002;Xu et al, 2006;Yang et al, 2006;Xu & Milliman, 2009;Yang et al, 2011). However, only a few papers have directly compared these two rivers (Xu et al, 2007;Bianchi & Allison, 2009).…”

Section: Introductionmentioning

confidence: 79%

A comparative study of the flux and fate of the Mississippi and Yangtze river sediments

Yang

2015

Proc. IAHS

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Large rivers play a key role in delivering water and sediment into the global oceans. Large-river deltas and associated coastlines are important interfaces for material fluxes that have a global impact on marine processes. In this study, we compare water and sediment discharge from Mississippi and Yangtze rivers by assessing: (1) temporal variation under varying climatic and anthropogenic impacts, (2) delta response of the declining sediment discharge, and (3) deltaic lobe switching and Holocene sediment dispersal patterns on the adjacent continental shelves. Dam constructions have decreased both rivers' sediment discharge significantly, leading to shoreline retreat along the coast. The sediment dispersal of the river-dominated Mississippi Delta is localized but for the tide-dominated Yangtze Delta is more diffuse and influenced by longshore currents. Sediment declines and relative sea level rises have led to coastal erosion, endangering the coasts of both rivers.

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Section: Introductionmentioning

confidence: 79%

A comparative study of the flux and fate of the Mississippi and Yangtze river sediments

Yang

2015

Proc. IAHS

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“…Most transport cells along depositional coastlines like the Gulf of Mexico have length scales of tens of km (Stone and Stapor 1996), and rates of longshore transport within cells, although inherently difficult to quantify (see Pilkey and Cooper 2002), can exceed 0.075 to 0.15 Mt/yr (million tons per year). For comparison, this mass of sediments is approximately two orders of magnitude less than the mass of sand delivered to coastal oceans by large rivers like the Mississippi (about 10-30 Mt/yr; Allison et al 2012;Blum and Roberts 2014), but is likely comparable to the discharge of sand to coastal oceans by many smaller rivers.…”

Section: Fluvial-shallow Marine To Deep Water Connectionsmentioning

confidence: 95%

Connections Between Fluvial To Shallow Marine Environments and Submarine Canyons: Implications For Sediment Transfer To Deep Water

Sweet

Blum

2016

Journal of Sedimentary Research

114

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The heads of submarine canyons represent a critical link in the transfer of sediment from terrestrial sources to deep basin sinks. Here we report data on grain size, bathymetry, and geochronology from twenty-five modern submarine canyons that suggest this link to be very sensitive to the distance between the canyon head and the shoreline, and, to a lesser extent, wave energy. These data show the width of this zone filters the caliber of sediment delivered into deep water, which has significant implications for understanding sediment budgets and the distribution of reservoir and seal facies.Data from modern systems show that the river mouths or longshore drift cells must come within about 500 m of the head of the canyon to deliver gravel-size material and within 1 to 5 km to deliver sand-size material to be transported down the canyon into deep water. Clay-and silt-size particles are transported greater distances across the shelf, up to a few tens of km, whereas beyond about 40 km, little sediment makes the connection to the heads of canyons and deposits are dominated by condensed, carbonate-rich sediments.Our data from modern systems are consistent with existing sequence stratigraphic models for sediment delivery to deep water. The significance of our work is to show in more detail how and when connections can occur between fluvial to shallow-water systems and submarine canyons and how these connections regulate the quantity and caliber of sediment that can be transported into deep water. Once the process-based conditions for connection are met, then the geology and climate of the source area control the quantity and caliber of sediment that can be moved to deep water.We hypothesize that connection times, and the resultant fractionation of sediment mass and grain size between shelf and deep-water depocenters, may have varied in a predictable way through geologic history. For example, during greenhouse times when sea level was relatively high, but with inherently low high-frequency variability, longer-lived connections between fluvial to nearshore environments and deep water may have been more likely. This scenario would favor the preferential transfer of sediment, especially sand, into deep water, and the development of thick, laterally extensive sand-rich basin-floor deposits. By contrast, during icehouse periods, high-amplitude sea-level fluctuations and inherently wider continental shelves may have resulted in repeated landward and seaward transits of river mouths and shorelines, shorter connection times between source and sink, especially for sand-size sediment, and preferential sequestration of sediment in shelf to shelf-margin parts of the system. These conditions would have resulted in deep-water deposits that are a mixture of locally thick sands, abundant turbidity-current-derived mud, and thin but basin-wide condensed sections that represent periods of sediment starvation in deep water.

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“…During the last deglaciation, the d 18 O w value of Mississippi River discharge into the Gulf of Mexico was determined by two factors: a d 18 O signal of continental precipitation integrated over the watershed, and seasonal contributions of meltwater from the melting LIS. The deglacial rate of freshwater influx from seasonally melting ice sheets has been estimated at 14,000 km 3 yr À1 (Fairbanks, 1989) during Meltwater Pulse 1a (MWP-1a), an interval of particularly rapid sea-level rise (40 mm yr À1 ; Deschamps et al, 2012); for comparison, this is 20x the modern annual average Mississippi River discharge of 700 km 3 yr À1 (Allison et al, 2012). Based on these estimates, meltwater from the LIS was a dominant component of Mississippi River discharge during parts of the deglaciation (Fairbanks et al, 1992).…”

Section: Planktic Foraminifer Ecology and Geochemistrymentioning

confidence: 99%

Oxygen isotope geochemistry of Laurentide ice-sheet meltwater across Termination I

Vetter

Spero

Eggins

et al. 2017

Quaternary Science Reviews

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a b s t r a c tWe present a new method that quantifies the oxygen isotope geochemistry of Laurentide ice-sheet (LIS) meltwater across the last deglaciation, and reconstruct decadal-scale variations in the d 18 O of LIS meltwater entering the Gulf of Mexico between~18 and 11 ka. We employ a technique that combines laser ablation ICP-MS (LA-ICP-MS) and oxygen isotope analyses on individual shells of the planktic values of Mississippi River discharge from discrete core intervals range from À22‰ to À38‰ VSMOW. These values suggest a dynamic melting history of different parts of the LIS, with potential contributions to Mississippi River outflow from both the low-elevation, southern margin of the LIS and high-elevation, high-latitude domes in the LIS interior that were transported to the ablation zone. Prior to~15.5 ka, the d 18 O water value of the Mississippi River was similar to that of regional precipitation or low-latitude LIS meltwater, but the Ba concentration in the Mississippi basin was affected by changes in weathering within the watershed, complicating Ba-salinity relationships in the Gulf of Mexico. After 13 ka, our data suggest Mississippi River outflow did not influence surface salinity above our Gulf of Mexico Orca Basin core site. Rather, we hypothesize that open ocean conditions prevailed as sea level rose and the paleoshoreline at the southern edge of North America retreated northward.

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A water and sediment budget for the lower Mississippi–Atchafalaya River in flood years 2008–2010: Implications for sediment discharge to the oceans and coastal restoration in Louisiana

Cited by 253 publications

References 37 publications

A comparative study of the flux and fate of the Mississippi and Yangtze river sediments

A comparative study of the flux and fate of the Mississippi and Yangtze river sediments

Connections Between Fluvial To Shallow Marine Environments and Submarine Canyons: Implications For Sediment Transfer To Deep Water

Oxygen isotope geochemistry of Laurentide ice-sheet meltwater across Termination I

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