Report on sedimentological investigations as part of the CICAR-Programme 1970-1972 . Part I . A reconnaissance survey of bottom sediments in the Amazon's mouth region
Tjoe-Awie, E.C. (1975). Report on sedimentological investigations as part of the CICAR-Programme 1970-1972 . Part I . A reconnaissance survey of bottom sediments in the Amazon's mouth region. NIOZ-rapport, 1975(19). Nederlands Instituut voor Onderzoek der Zee: Texel. 51, 30 pp.
Part of: NIOZ-rapport. Netherlands Institute for Sea Research (NIOZ): Den Burg. ISSN 0923-3210, more
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| Abstract |
As part of the CICAR programmes carried out in September - October, 1970 and in May 1971, both suspended matter and bottom sediments were collected in the Amazon's mouth region. The materials were used for an investigation regarding the spreading of bottom sediments in that area. The highest concentrations of suspended matter are found near the bottom. From bottom to surface of the water the concentration of suspended solids decreases rapidly. Furthermore the amounts of suspended solids found at a certain depth greatly depends on the phase of the tide. In the superficial waterlayer the concentration of suspended matter decreases with the distance to the coast. The 20- metres isobath was found to parallel the 5 mg/l isoconcentration line which should be considered the outward limit where appreciable amounts of Amazon - transported solids can be found in the surface waters. Analyses of bottom sediments with regard to their bulk densities, carbonate content, grain-size distribution C/N- ratios and cation exchange characteristics have been carried out. From the data it appeared that differentiation of the Amazonas-transported sediments are brought about in accordance with prevailing hydrodynamic conditions of the environment. Some results point to mixing of Amazon-derived sediments with the slightly different River Para-transported deposits. The thus produced generalized map of bottom sediments strongly bears a genetic character. |
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