Concentration and flux of suspended sediment on the Amazon continental shelf

Nittrouer, Charles A.; Curtin, Tom; DeMaster, David J.

doi:10.1016/0278-4343(86)90058-0

Cited by 120 publications

(48 citation statements)

References 38 publications

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“…Such a clay mineral trend points to the existence of active winnowing processes in a direction within the oceanic domain that is normal to that of the river flux. It is assumed to result from sorting mechanisms determined by the North Brazil Current, which is annually responsible for the westward transportation of about 10 8 metric tons of suspended matter (Allersma, 1971;Nittrouer et al, 1986Nittrouer et al, , 1995.…”

Section: Spatial Distributionmentioning

confidence: 99%

Clay mineral distribution and significance in Quaternary sediments of the Amazon Fan

Debrabant¹,

López²,

Chamley³

1997

Proceedings of the Ocean Drilling Program, 155 Scientific Results

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The clay mineral assemblages of samples from the Amazon Fan were investigated in middle Pleistocene to Holocene sediments from 16 Ocean Drilling Program Leg 155 sites and were placed in lithologic successions to study continental evolution and transport conditions. The sediments sampled along a transect parallel to the main channel reflect moderate differential settling processes, whereas those studied along a transect roughly parallel to the coast clearly suggest winnowing effects related to the North Brazil Current. High-resolution analyses of Holocene deposits reflect the dominant influence of downstream soil erosion relative to supply from the Andean range and the progressive increase of soil-derived relative to rock-derived outputs. The middle Pleistocene to uppermost Pleistocene and Holocene successions are marked by a constantly warm climatic background and by noticeable modifications in the rock-derived (illite, chlorite) and soil-derived (smectite, kaolinite) products. These products successively reflect sea-level changes, tectonic rejuvenation in the Andean range, regressive erosion, and rainfall increase.

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Section: Spatial Distributionmentioning

confidence: 99%

Clay mineral distribution and significance in Quaternary sediments of the Amazon Fan

Debrabant¹,

López²,

Chamley³

1997

Proceedings of the Ocean Drilling Program, 155 Scientific Results

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“…Faas 1987;Gibbs and Konwar 1986;Nittrouer et al 1986;Wells and Roberts 198 1). In some estuaries for SSC > 10 g liter-', the lutocline can be very thin, of the order of centimeters, while the bottom layer can be only 1 m thick, and the system may not destratify at slack tidal currents (e.g.…”

Section: Mixing Across a Lutoclinementioning

confidence: 99%

Mixing across a lutocline

Wolanski

Asaeda

Imberger

1989

Limnology & Oceanography

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The results of a laboratory experiment showed that mixing across a lutocline (the interface between clear water on top and a fluid‐mud mixture underneath) is controlled not only by mud‐induced buoyancy effects through a Richardson‐number dependence, but also by the sediment‐induced collapse of turbulence in the fluid‐mud layer. The dependence of particle settling velocity on the concentration of suspended sediment can limit the height of resuspension of sediments and stop lutocline erosion after an initial period of active mixing.

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“…The presented results (as showed in Table 1) sometimes differ in their methods QS (10 6 t yr-1) Source 500 (Gibbs, 1967) 600 (Oltman, 1968) 900 (Meade et al, 1979) 1,100 -1,300 550 -1,000 Nittrouer et al, 1986a) 600 -700 (Bordas 1988;Filizola,1999)* 600 -800 (Filizola 2003), Guyot et al, 2005 andFilizola and (2011) give a summary of measurement periods for TSS monitoring in their table 2. Further, discrepancies could be attributed to variability in hydrological behaviour, sampling methods, sediment discharge calculation, and others topics discussed further in this section.…”

Section: The Significance Of Suspended Sediment Discharge Values To Tmentioning

confidence: 84%

“…From this river, Martinelli et al (1989;1993) and Ferreira et al (1988) estimated a somewhat higher suspended sediment discharge of approximately 550 10 6 t yr -1 . The Amazon Shelf SEDiment Study (AmasSeds) group, working with a 190 CTD Probe profiles at the continental shelf, indicated a total flux between 550 and 1,000 10 6 t yr -1 from the Amazon River into the ocean (Nittrouer et al, 1986a and. In the scope of the HiBAm (Hydrology and Geochemistry of the Amazon Basin) Project until 2001 when it was completed and after that until today with the ORE/HYBAM (Environmental Research Observatory on Amazon Basin Hydrology, Geochemistry and Geodynamics) Program, Guyot et al (1996), Filizola (1999, Filizola (2003), Filizola and Guyot (2004), Guyot et al (2005) and calculated the contributions from tributaries to the main stream during several cruises (HiBAm and ORE/HYBAM data) and using data from the Brazilian National Data set (from Brazilian Agência Nacional de Águas).…”

mentioning

confidence: 99%