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| Lartaud, Franck; De Rafelis, Marc; Oliver, Graham; Krylova, Elena; Dyment, Jerome; Ildefonse, Benoit; Thibaud, Remy; Gente, Pascal; Hoise, Eva; Meistertzheim, Anne-leila; Fouquet, Yves; Gaill, Francoise; Le Bris, Nadine. |
| Hydrothermal circulation at ultramafic-hosted sites supports a large variety of high-and low-temperature hydrothermal vents and associated ecosystems. The discovery of abundant fossil vesicomyid and thyasirid shell accumulations at the ridge crest, approximately 2.5 km east of the active Rainbow vent field on the Mid-Atlantic Ridge (MAR, 36 degrees 13'N), increased our knowledge regarding the diversity of vent communities at slow spreading ridges. Bivalve molluscs of the family Vesicomyidae were represented by the genus Phreagena. Here we present the first record of this genus in the Atlantic Ocean. This second vesicomyid species known from the MAR, Phreagena sp., was found to be associated with a Thyasira species that is affiliated with T. southwardae (at... |
| Tipo: Text |
Palavras-chave: Ultramafic-hosted; Mid-Atlantic Ridge; Bivalve shells; Vesicomyidae; Thyasiridae; Carbon and oxygen isotopes. |
| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00012/12301/9093.pdf |
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| Auzende, Jean-marie; Cannat, M; Gente, Pascal; Henriet, Jean-pierre; Juteau, Thierry; Karson, J; Lagabrielle, Yves; Mevel, Christophe; Tivey, M. |
| The aim of the 20 Nautile dives of the recent Kanaut cruise was the study of the Kane Fracture Zone from its intersection with the Mid-Atlantic Ridge up to 80 km to the west. The dives have been conducted along four massifs located along the southern wall of the fracture valley. The flanks of the massifs consist of slightly tilted peridotites, gabbros and basalts, which have been exposed along normal and strike-slip major faults. No dike complex similar to that observed along the ZF Vema was observed The observed sections show pervasive cataclastic deformation and greenschist-facies metamorphic overprint. |
| Tipo: Text |
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| Ano: 1993 |
URL: http://archimer.ifremer.fr/doc/00183/29470/27886.pdf |
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| Maia, Marcia; Pessanha, Ivo; Courreges, Esther; Patriat, Martin; Gente, Pascal; Hemond, Christophe; Janin, Myriam; Johnson, Kevin; Roest, Walter; Royer, Jean-yves; Vatteville, Judith. |
| The Amsterdam-Saint Paul plateau results from a 10 Myr interaction between the South East Indian Ridge and the Amsterdam-Saint Paul hot spot. During this period of time, the structure of the plateau changed as a consequence of changes in both the ridge-hot spot relative distance and in the strength of the hot spot source. The joint analysis of gravity-derived crust thickness and bathymetry reveals that the plateau started to form at similar to 10 Ma by an increase of the crustal production at the ridge axis, due to the nearby hot spot. This phase, which lasted 3-4 Myr, corresponds to a period of a strong hot spot source, maybe due to a high temperature or material flux, and decreasing ridge-hot spot distance. A second phase, between similar to 6 and... |
| Tipo: Text |
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| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00047/15865/13284.pdf |
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| D'Acremont, Elia; Leroy, Sylvie; Maia, Marcia; Patriat, Philippe; Beslier, Marie-odile; Bellahsen, Nicolas; Fournier, Marc; Gente, Pascal. |
| Magnetic and gravity data gathered during the Encens-Sheba cruise (2000 June) in the eastern Gulf of Aden provide insights on the structural evolution of segmentation from rifted margins to incipient seafloor spreading. In this study, we document the conjugate margins asymmetry, confirm the location of the ocean-continent transition (OCT) previously proposed by seismic data, and describe its deep structure and segmentation. In the OCT, gravity models indicate highly thinned crust while magnetic data indicate presence of non-oceanic high-amplitude magnetic anomalies where syn-rift sediments are not observed. Thus, the OCT could be made of ultra-stretched continental crust intruded by magmatic bodies. However, locally in the north, the nature of the OCT... |
| Tipo: Text |
Palavras-chave: Gulf of Aden; Kinematic evolution; Ocean-continent transition; Passive continental margin; Seafloor spreading; Segmentation. |
| Ano: 2006 |
URL: https://archimer.ifremer.fr/doc/00234/34561/33314.pdf |
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| Auzende, Jean-marie; Eissen, Jean-philippe; Caprais, Marie-paule; Gente, Pascal; Gueneley, S; Harmegnies, Francois; Lagabrielle, Yves; Lapouille, A; Lefevre, C; Maillet, P; Maze, Jean-pierre; Ondreas, Helene; Schaaf, A; Singh, R. |
| Seismic, Seabeam, magnetic and gravimetrie surveys in the southern part of the N-Fiji basin were conducted during the SEAPSO LEG III Cruise. The active spreading axis was recognized between 17°30'S and 21°S. It consists of a continuous N-S Ridge cross-cut by transverse directions oriented N25 and N45. North of 17°30'S, the spreading System is more complex due to the existence of a possible triple junction located around 15° S. The eastern part of the N-Fiji basin, west of Viti Levu is mostly characterized by alternating highs and deeps (<4,000 m). This area must be regarded no more as a spreading center, but as complex boundary suffering transverse tectonics. |
| Tipo: Text |
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| Ano: 1986 |
URL: http://archimer.ifremer.fr/doc/00184/29492/27835.pdf |
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| Gente, Pascal. |
| Ce mémoire contient les résultats d'une étude comparative menée sur la morphologie et la structure de différentes dorsales océaniques. Ces frontières divergentes de plaques lithosphériques sont le siège d'évènements tectoniques, volcaniques et hydrothermaux. L'analyse d'un grand nombre de données bathymétriques, structurales (sonar latéral) et d'observations sur le fond (a l'aide du submersible SP 3000 Cyana), sur plusieurs secteurs de différentes dorsales à taux d'expansion variés, constitue la base de ce travail. |
| Tipo: Text |
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| Ano: 1987 |
URL: http://archimer.ifremer.fr/doc/00034/14517/11837.pdf |
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| Le Saout, M; Thibaud, R.; Gente, Pascal. |
| Spreading processes at the axes of fast spreading ridges are mainly controlled by magmatic activity, whereas tectonic activity dominates further away from the axis. High-resolution near-bottom bathymetry data, photographs, videos, and human observations from submersible surveys are used to develop a detailed tectonic analysis of the 16 degrees N segment of the East Pacific Rise (EPR). These data are used to evaluate how a highly magmatic segment, close to a hot spot, affects the nucleation and evolution of faulting patterns and impacts the evaluation of tectonic strain within 2km of the spreading axis. Our study shows that (1) the growth of tectonic features differs in response to dike intrusion and tectonic extension, (2) the initiation of brittle... |
| Tipo: Text |
Palavras-chave: Faulting; Dike intrusion; Brittle deformation; Mid-ocean ridge; East Pacific Rise. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00638/74985/75818.pdf |
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