River Discharge to the Coastal Ocean

Milliman, John D.; Farnsworth, Katherine L.

doi:10.1017/cbo9780511781247

Cited by 838 publications

(731 citation statements)

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“…Taken together, the cumulative area of the major river basins investigated in this study with watersheds larger than >100,000 km 2 (n = 17; excluding the Benue River, i.e. a tributary of the Niger River) accounts for a total of 26.4 Â 10 6 km 2 , hence representing about 25% of the entire continental area that drains into the global ocean (105 Â 10 6 km 2 ; Milliman and Farnsworth, 2011). In terms of sediment discharge, these rivers export altogether about 2.7 Gt of suspended particles each year, which represents about 15% of the annual sediment flux to the global ocean (about 18 Gt/yr; Milliman and Syvitski, 1992).…”

Section: The Si Isotopic Composition Of the Unweathered And Weatheredmentioning

confidence: 91%

The silicon isotopic composition of fine-grained river sediments and its relation to climate and lithology

Bayon

Delvigne

Ponzevera

et al. 2018

Geochimica et Cosmochimica Acta

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The d 30 Si stable isotopic composition of silicon in soils and fine-grained sediments can provide insights into weathering processes on continents, with important implications on the Si budget of modern and past oceans. To further constrain the factors controlling the distribution of Si isotopes in sediments, we have analysed a large number (n = 50) of separate size-fractions of sediments and suspended particulate materials collected near the mouth of rivers worldwide. This includes some of the world's largest rivers (e.g. Amazon, Congo, Mackenzie, Mississippi, Murray-Darling, Nile, Yangtze) and rivers from the case study areas of the Congo River Basin and Northern Ireland. Silt-size fractions exhibit a mean Si isotopic composition (d 30 Si = À0.21 ± 0.19‰; 2 s.d.) similar to that previously inferred for the upper continental crust. In contrast, clay-size fractions display a much larger range of d 30 Si values from À0.11‰ to À2.16‰, which yield a global d 30 Si clay of À0.57 ± 0.60‰ (2 s.d.) representative of the mean composition of the average weathered continental crust. Overall, these new data show that the Si isotopic signature transported by river clays is controlled by the degree of chemical weathering, as inferred from strong relationships with Al/Si ratios. At a global scale, the clay-bound Si isotopic composition of the world's largest river systems demonstrates a link with climate, defining a general correlation with mean annual temperature (MAT) in corresponding drainage basins. While the distribution of Si isotopes in river sediments also appears to be influenced by the tectonic setting, lithological effects and sediment recycling from former sedimentary cycles, our results pave the way for their use as paleo-weathering and paleo-climate proxies in the sedimentary record.

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Section: The Si Isotopic Composition Of the Unweathered And Weatheredmentioning

confidence: 91%

The silicon isotopic composition of fine-grained river sediments and its relation to climate and lithology

Bayon

Delvigne

Ponzevera

et al. 2018

Geochimica et Cosmochimica Acta

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“…In recent decades, the transfer of suspended sediment to the sea from many of the world's rivers has drastically decreased as a result of human activities, primarily the construction of dams and irrigation (e.g., Dai et al 2009;Meade and Moody 2010;Milliman and Farnsworth 2011, and references therein), thereby influencing the rivers' deltas (e.g., Syvitski et al 2009;Yang et al 2011 and references therein). The response of SSC in estuarine and adjacent waters to human activities, however, has seldom been addressed (Schoellhamer 2011), probably due to a lack of adequate datasets.…”

Section: Surface Ssc In the Yangtze Estuary In Response To Decreasingmentioning

confidence: 99%

Spatial, Temporal, and Human-Induced Variations in Suspended Sediment Concentration in the Surface Waters of the Yangtze Estuary and Adjacent Coastal Areas

Yang

Milliman

et al. 2012

Estuaries and Coasts

111

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To delineate temporal and spatial variations in suspended sediment concentration (SSC) in the Yangtze (Changjiang) Estuary and adjacent coastal waters, surfacewater samples were taken twice daily from 10 stations over periods ranging from 2 to 12 years (total number of samples >28,000). Synoptic measurements in 2009 showed an increase in surface SSC from 0.058 g/l in the upper sections of the estuary to ∼0.6 g/l at the Yangtze River turbidity maximum at the river mouth, decreasing seaward to 0.057 g/l. Annual periodicities reflect variations in the Yangtze discharge, which affect the horizontal distribution and transport of SSC, and seasonal winds, which result in vertical resuspension and mixing. Over the past 10-20 years, annual surface SSC in the lower Yangtze River and the upper estuary has decreased by 55%, due mainly to dam construction in the upper and middle reaches of the river. The 20-30% decrease in mean surface SSC in the lower estuary and adjacent coastal waters over the same period presumably reflects sediment resuspension, in part due to erosion of the subaqueous Yangtze Delta. SSCs in the estuary and adjacent coastal waters are expected to continue to decline as new dams are constructed in the Yangtze basin and as erosion of the subaqueous delta slows in coming decades.

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“…This value corresponds to the lower limit 511 of modern West African solid river loads (3.5 -300 t/km 2 /yr) and to the 4 t/km 2 /yr 512 measured at the outlet of the Volta catchment (Milliman and Farnsworth, 2013). …”

Section: Interpretation Of the Pediplain Dissection Pattern 416mentioning

confidence: 69%

Neogene cratonic erosion fluxes and landform evolution processes from regional regolith mapping (Burkina Faso, West Africa)

et al. 2015

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River Discharge to the Coastal Ocean

Cited by 838 publications

References 0 publications

The silicon isotopic composition of fine-grained river sediments and its relation to climate and lithology

The silicon isotopic composition of fine-grained river sediments and its relation to climate and lithology

Spatial, Temporal, and Human-Induced Variations in Suspended Sediment Concentration in the Surface Waters of the Yangtze Estuary and Adjacent Coastal Areas

Neogene cratonic erosion fluxes and landform evolution processes from regional regolith mapping (Burkina Faso, West Africa)

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