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| Pujos, M; Pons, Jc; Parra, M. |
| The distribution of heavy minerals on beaches and beach ridges sands of French Guiana shows three distinct suites from East to West: amphibole (largely dominant), staurolite, epidote and pyroxene off the Cayenne region, tourmaline and amphibole mainly off the Kourou-Mana, garnet, staurolite and tourmaline off the Mana-Maroni. A very good continuity exists between the assemblages of heavy minerals from the catchment area parent-rocks, the fluviatile sediments, the coastal zone and the shelf. The results of this study indicate and strengthen a local origin for the sandy sediments and do not support a possibility of an Amazonian source. |
| Tipo: Text |
Palavras-chave: Guyane française; Plages; Cordons sableux; Minéraux lourds; French Guiana; Beaches; Beach ridges sands; Heavy minerals. |
| Ano: 2001 |
URL: http://archimer.ifremer.fr/doc/00291/40271/38643.pdf |
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| Pujos, M; Latouche, C; Maillet, N. |
| Marine muds deposited on the French Guiana coast mostly originate in the Amazon. Recent sediments are composed of (a) illite (33 %) and chlorite (13 %) of Andean mountain origin; and (b) kaolinite (28 %) and smectite (26 %), principally from the Amazonian lowlands but also from the Guiana Shield. In the coastal mud prism, high-resolution seismic profiles, together with sedimentological, micropaleontological and soil engineering studies, supplemented by C-14 dates, permitted a stratigraphic interpretation of eight cores. Three episodes have been determined on the basis of clay-mineral variations related to Amazonian lowland, Andean and Guiana shield sources. The older episodes 3 (3000-1700 y BP) and 2 (1700-1000 y BP) are predominantly characterized by... |
| Tipo: Text |
Palavras-chave: Late quaternary; French Guiana; Shelf; Clay minerals; ENSO. |
| Ano: 1996 |
URL: http://archimer.ifremer.fr/doc/00094/20506/18175.pdf |
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| Pujos, M; Monente, J; Latouche, C; Maillet, N. |
| The suspended matter transported by the Orinoco to the Orinoco delta originates mainly in the Colombian Andes. The four clayey minerals (kaolinite, chlorite, illite and smectite) are always present in the deltaic suspensions, the delta deposits and the gulf of Paria. Illite contents are always dominant except in those regions of the gulf of Paria situated far from the mouths of the Orinoco tributaries characterized by smectites. In the delta, illite contents which are minimal during the dry season increase noticeably during the wet season which is marked by a high Liquid and particulate matter discharge. In the delta, the clay mineralogy of the substrate is comparable to that of dry season suspensions (February), thus showing a sedimentation composed of... |
| Tipo: Text |
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| Ano: 1997 |
URL: http://archimer.ifremer.fr/doc/00093/20435/18102.pdf |
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| Pujos, M; Griboulard, R; Latouche, C; Meidinger, P. |
| The continental shelf is very narrow and steep to the north, and broader to the South. This shelf is structuraly influenced by the Andes. This area is mainly covered with terrigenous deposits, i.e. muds and sands which are recent on the internal shelf and relict on the external shelf. The sediments, supplied by rivers, reflect the intense erosion of the Andean backland. This erosion can only be reduced in situ by the vegetation cover. Clays are the main component of the fine fraction reaching the sea. Three different clay assemblages are observed: 1) an Andean (illite-chlorite) assemblage, reflecting the proximity of the cordillera; 2) a mid-American assemblage (smectite), which supplies the North Pacific Margin through the Choco counter-current; 3) an... |
| Tipo: Text |
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| Ano: 1995 |
URL: http://archimer.ifremer.fr/doc/00097/20862/18480.pdf |
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| Carbonel, P; Pujos, M. |
| The bentonic microfauna of ostracodas and foraminiferas of Tunis lake is controlled for a reduced number of species (always the same), which are representative of a very isolated habitat type of the marine environment. The characteristic species (Cyprideis gr. Torosa and Ammonia gr. beccarii ) have a variable morphology; each of them presents three ecotypes which are the reflections of the water hydrochemical conditions (salt concentrations, ionic balance, dissolved oxygen). The observed specific variability in these organisms allows one to perceive the environment variations which cannot be discerned from a classical microfaunas approach. |
| Tipo: Text |
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| Ano: 1982 |
URL: http://archimer.ifremer.fr/doc/00246/35705/34214.pdf |
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