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| Mascle, J; Guiraud, M; Benkhelil, J; Basile, C; Bouillin, Jp; Mascle, G; Cousin, M; Durand, M; Dejax, J; Moullade, M. |
| During the Equanaute survey (June 1992), fourteen submersible dives were performed between 4950 and 2250 m water depths across the southern slope of the Cote d'Ivoire-Ghana Marginal Ridge (CIGMR), in the eastern Equatorial Atlantic. The CIGMR, a high-standing topographic marginal ridge along the Cote d'Ivoire-Ghana transform margin, is believed to result from a complex structural evolution due to the specific wrench-related rifting between Western Equatorial Africa and Northeastern Brazil, in Early Cretaceous times. In this paper we report and discuss geological observations made during dives, and sample analyses to resolve the lithology, paleoenvironmental conditions, age and origin of the CIGMR. The data help in better characterizing the different... |
| Tipo: Text |
Palavras-chave: Marge transformante; Géologie; Côte d’lvoire-Ghana; Atlantique Equatorial; Transform margin; Geology; Côte d’Ivoire-Ghana; Equatorial Atlantic. |
| Ano: 1998 |
URL: http://archimer.ifremer.fr/doc/00326/43694/43118.pdf |
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| Evangelista, H.; Sifeddine, A.; Correge, T.; Servain, J.; Dassie, E. P.; Logato, R.; Cordeiro, R. C.; Shen, C. -c.; Le Cornec, F.; Nogueira, J.; Segal, B.; Castagna, A.; Turcq, B.. |
| Although relatively rare compared to similar latitudes in the Pacific or Indian Oceans, massive coral colonies are present in the Tropical/Equatorial Southwestern Atlantic Ocean. However, detailed geo-chemical compositions of these corals are still largely unknown. In this work, we present growth rates, Sr/Ca, and U/Ca ratios of the coral colony (Siderastrea stellata) sampled at Rocas Atoll, off the Brazilian coast. These variables are primarily affected by sea surface temperature (SST) at seasonal scale, and by wind stress at interannual scale, these results represent a broad new finding. A lower significance at the interannual time scale between Sr/Ca and U/Ca with respect to SST is attributed to the low SST amplitude closed to Equator. An investigation... |
| Tipo: Text |
Palavras-chave: Coral; Siderastrea stellata; Rocas Atoll; ITCZ; Equatorial Atlantic; Wind stress. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00623/73552/73796.pdf |
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| Chambault, Philippine; Giraudou, Lucie; De Thoisy, Benoit; Bonola, Marc; Kelle, Laurent; Dos Reis, Virginie; Blanchard, Fabian; Le Maho, Yvon; Chevallier, Damien. |
| The identification of the inter-nesting habitat used by gravid sea turtles has become a crucial factor in their protection. Their aggregation in large groups of individuals during the inter-nesting period exposes them to increased threats to their survival - particularly along the French Guiana shield, where intense legal and illegal fisheries occur. Among the three sea turtle species nesting in French Guiana, the olive ridley appears to have the most generalist diet, showing strong behavioural plasticity according to the environment encountered. The large amounts of sediments that are continuously discharged by the Amazon River create a very unusual habitat for olive ridleys, i.e. turbid waters with low salinity. This study assesses the behavioural... |
| Tipo: Text |
Palavras-chave: Lepidochelys olivacea; Equatorial Atlantic; Inter-nesting season; Behavioural synchrony; Amazon River. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00354/46507/46269.pdf |
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| Sichler, Bertrand; Hekinian, Roger. |
| The St. Paul Fracture Zone (FZ) in the equatorial Atlantic is interrupted by three intratransform ridge (ITR) spreading centers. A detailed magnetic survey, corrected for the diurnal variations using a moored magnetic station, six submersible dives, and three bottom-towed video camera tracks provide data on the most eastern ITR (0degrees37'N, 25degrees27'W). Visual observations and submersible sampling displayed a high ultramafic/volcanic ratio, supporting the assumption that the ITR is in a magmatically starved state. Volcanics were mainly found on the rift valley floor from 4700 to 4000 m and as a thin cap (<160 m) on the top of the eastern rift crest (2700 m). Most of the rift walls consist essentially of serpentinized peridotites and gabbros. The... |
| Tipo: Text |
Palavras-chave: Magnetic anomaly; Equatorial Atlantic; Stochastic inversion. |
| Ano: 2002 |
URL: http://archimer.ifremer.fr/doc/00000/10223/9585.pdf |
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| Mercier, Herle; Arhan, Michel; Lutjeharms, Johann. |
| The upper-layer circulation in the eastern basin of the South Atlantic was studied from hydrographic and direct velocity measurements along WOCE lines A11, A13 and A14. A13 and A14 provide quasi-meridional samplings of the equatorial, subequatorial and subtropical circulation regimes. A13 was carried out along the African coast at about 600 km offshore from it, and A 14 along the nominal longitude 9degreesW. A11 intersects the Cape Basin between 46degreesS in the west and 30degreesS in the east. Transport estimates were derived from direct velocity measurements and a box inverse model. In the equatorial eastern Atlantic, the Equatorial Undercurrent (EUC) transport decreases from 25x10(6) m(3) s(-1) at 9degreesW to 13x10(6) m(3) s(-1) at 5degreesE.... |
| Tipo: Text |
Palavras-chave: Hydrography; Current; Circulation; South Atlantic; Equatorial Atlantic. |
| Ano: 2003 |
URL: https://archimer.ifremer.fr/doc/2003/publication-460.pdf |
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