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| Escartin, Javier; Leclerc, Frederique; Olive, Jean-arthur; Mevel, Catherine; Cannat, Mathilde; Petersen, Sven; Augustin, Nico; Feuillet, Nathalie; Deplus, Christine; Bezos, Antoine; Bonnemains, Diane; Chavagnac, Valerie; Choi, Yujin; Godard, Marguerite; Haaga, Kristian A.; Hamelin, Cedric; Ildefonse, Benoit; Jamieson, John W.; John, Barbara E.; Leleu, Thomas; Macleod, Christopher J.; Massot-campos, Miguel; Nomikou, Paraskevi; Paquet, Marine; Rommevaux-jestin, Celine; Rothenbeck, Marcel; Steinfuehrer, Anja; Tominaga, Masako; Triebe, Lars; Campos, Ricard; Gracias, Nuno; Garcia, Rafael; Andreani, Muriel; Vilaseca, Geraud. |
| Properly assessing the extent and magnitude of fault ruptures associated with large earthquakes is critical for understanding fault behavior and associated hazard. Submarine faults can trigger tsunamis, whose characteristics are defined by the geometry of seafloor displacement, studied primarily through indirect observations (e.g., seismic event parameters, seismic profiles, shipboard bathymetry, coring) rather than direct ones. Using deep-sea vehicles, we identify for the first time a marker of coseismic slip on a submarine fault plane along the Roseau Fault (Lesser Antilles), and measure its vertical displacement of ∼0.9 m in situ. We also map recent fissuring and faulting of sediments on the hangingwall, along ∼3 km of rupture in close proximity to the... |
| Tipo: Text |
Palavras-chave: Submarine fault; Surface rupture; Earthquake; Fault slip; Neotectonics; Microbathymetry. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00344/45500/45051.pdf |
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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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| Andreani, Muriel; Escartin, Javier; Delacour, Adelie; Ildefonse, Benoit; Godard, Marguerite; Dyment, Jerome; Fallick, Anthony E.; Fouquet, Yves. |
| Rainbow is a dome-shaped massif at the 36°14′N nontransform offset along the Mid-Atlantic Ridge. It hosts three ultramafic-hosted hydrothermal sites: Rainbow is active and high temperature; Clamstone and Ghost City are fossil and low temperature. The MoMARDREAM cruises (2007, 2008) presented here provided extensive rock sampling throughout the massif that constrains the geological setting of hydrothermal activity. The lithology is heterogeneous with abundant serpentinites surrounding gabbros, troctolites, chromitites, plagiogranites, and basalts. We propose that a W dipping detachment fault, now inactive, uplifted the massif and exhumed these deep-seated rocks. Present-day deformation is accommodated by SSW-NNE faults and fissures, consistent with oblique... |
| Tipo: Text |
Palavras-chave: Rainbow; Hydrothermal; Serpentinization; Atlantic ridge. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00210/32151/30609.pdf |
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| Lartaud, Franck; Little, Crispin T. S.; De Rafelis, Marc; Bayon, Germain; Dyment, Jerome; Ildefonse, Benoit; Gressier, Vincent; Fouquet, Yves; Gaill, Francoise; Le Bris, Nadine. |
| Among the deep-sea hydrothermal vent sites discovered in the past 30 years, Lost City on the Mid-Atlantic Ridge (MAR) is remarkable both for its alkaline fluids derived from mantle rock serpentinization and the spectacular seafloor carbonate chimneys precipitated from these fluids. Despite high concentrations of reduced chemicals in the fluids, this unique example of a serpentinite-hosted hydrothermal system currently lacks chemosynthetic assemblages dominated by large animals typical of high-temperature vent sites. Here we report abundant specimens of chemosymbiotic mussels, associated with gastropods and chemosymbiotic clams, in approximately 100 kyr old Lost City-like carbonates from the MAR close to the Rainbow site (36 degrees N). Our finding shows... |
| Tipo: Text |
Palavras-chave: Bathymodiolus; Ghost City; Ultramafic-hosted; Mid-ocean ridge; Ecogeochemistry. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00036/14748/15832.pdf |
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