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| Gaillard, M; Lang, J; Lucas, J. |
| The littoral area of Benin is a lagoonal-estuarial, indeed even deltaic, environment. Poor in species, the mangrove of Benin belongs to the tropical Atlantic type tending to be humid, considering the "drought belt" which affects this region. It undergoes profound hydrological changes in the course of the different seasons in relation to the Mono and Couffo Rivers. The granulometric analysis and the study of the facies makes clear a lenticular-type sedimentation in relation to numerous and rapid hydrodynamic variations. The clayish quartzose sediment also contains a chemical phase (pyrite is transformed through oxidation into jarosite, gypsum and halite in relation to the micromilieux of evaporation) and an important organic phase - with a pH level ranging... |
| Tipo: Text |
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| Ano: 1982 |
URL: http://archimer.ifremer.fr/doc/00246/35730/34238.pdf |
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| Marius, C; Lucas, J. |
| The mangroves of Senegal are limited to the inlet of the Casamance - a river with very low discharge - and to the Sine-Saloum. The mineralogical and geochemical analysis of sediments (derived from 30 deep bore-holes) shows the thickness of the mangrove substrate, which overlies the continental terminal formation. Kaolinite and smectite account for over 90% of the clay fraction. The former is derived from the continental terminal whereas the latter is of marine origin. The chemical composition of the mangrove sediments is remarkably stable and clays play an overwhelming role in the preservation of organic matter and pyrite. Since 1968, a drought in Senegal has caused an important increase in the salinity levels of streams and water-tables; a considerable... |
| Tipo: Text |
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| Ano: 1982 |
URL: http://archimer.ifremer.fr/doc/00246/35744/34252.pdf |
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