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| Copley, Jtp; Tyler, Pa; Sheader, M; Murton, Bj; German, Cr. |
| 101 species were identified from 102 biological samples obtained between 225 and 2600 m depth on the Reykjanes Ridge, extending the biogeographic records for several species. Multivariate analysis of between-sample species similarity reveals a two-zone bathymetric faunal distribution with the transition at 800-1000 m. A hydrographic survey of the ridge axis suggests that this faunal zonation is influenced by the water mass structure. Despite the limitations of a sampling programme not designed a priori for biological sampling, the recovery and preservation of the samples and the insight that they provide serves to reinforce that every effort should be made to capitalise on the opportunities for obtaining samples afforded by non-biological sampling... |
| Tipo: Text |
Palavras-chave: Mid-ocean ridge; Megafauna; Reykjanes Ridge; Bathymetric zonation; Water mass structure. |
| Ano: 1996 |
URL: http://archimer.ifremer.fr/doc/00096/20725/18362.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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| Escartin, J.; Barreyre, T.; Cannat, M.; Garcia, R.; Gracias, N.; Deschamps, A.; Salocchi, A.; Sarradin, Pierre-marie; Ballu, V.. |
| We have reviewed available visual information from the seafloor, and recently acquired microbathymetry for several traverses across the Lucky Strike segment, to evaluate the distribution of hydrothermal activity. We have identified a new on-axis site with diffuse flow, Ewan, and an active vent structure ∼1.2 km from the axis, Capelinhos. These sites are minor relative to the Main field, and our total heatflux estimate for all active sites (200–1200 MW) is only slightly higher than previously published estimates. We also identify fossil sites W of the main Lucky Strike field. A circular feature ∼200 m in diameter located on the flanks of a rifted off-axis central volcano is likely a large and inactive hydrothermal edifice, named Grunnus. We find no... |
| Tipo: Text |
Palavras-chave: Hydrothermalism; Mid-ocean ridge; Heat flux; Faulting; Oceanic crust; Mid-Atlantic Ridge. |
| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00281/39241/37812.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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