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| Karpoff, A. M.; Sauter, D.; Cannat, M.; Ulrich, M.; Manatschal, G.. |
| On the smooth seafloor of exhumed mantle-rocks of the slow-spreading Southwest Indian Ridge, the secondary oxide and carbonate mineralizations record specific chemical signatures of the alteration of serpentinites by low-temperature hydrothermal seawater-dominated fluids. The uncommon characteristics of Fe-oxides forming nodule cortex or thick encrustments are their high Si, low Mn contents, trace elements (e.g. Cr) and REE behavior. Oxides composition evolves through time. Associated to oxides, carbonates (aragonite, calcite, dolomite) characterize the matrix of young indurated serpentinite breccias found at ridge axis. Such mineralogical and geochemical sequences trace, as proxies, the ongoing mantle-exhumation and serpentinization process linked to the... |
| Tipo: Text |
Palavras-chave: Si-Fe-oxides; Hydrothermalism; Seawater-dominated fluids; Serpentinites; Mantle exhumation; Indian Ocean; SWIR. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00367/47771/47821.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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| Dekov, V.m.; Egueh, N. M.; Kamenov, G. D.; Bayon, G.; Lalonde, S.v.; Schmidt, M.; Liebetrau, V.; Munnik, F.; Fouquet, Yves; Tanimizu, M.; Awaleh, M. O.; Guirreh, I.; Le Gall, B.. |
| Carbonate chimney-like deposits up to 60 m high are scattered or arranged in rows at the shores of a desiccating hypersaline and alkaline lake from a continental rift setting (Lake Abhé, Afar Rift, Djibouti). The chimneys formed sub-aqueously in the lake water body at a higher water level than observed today. Alternating calcite and low-Mg calcite + silica concentric layers compose the chimney structures. Mineralogical and geochemical investigations of the chimneys, lake water, and hot spring (hydrothermal) fluids suggest that the chimneys are a result of rapid carbonate precipitation during the mixing of hydrothermal fluids with lake water. In contrast to the hot spring fluid, lake water is enriched in HREE and possesses a pronounced positive Ce anomaly,... |
| Tipo: Text |
Palavras-chave: Carbonate; Chimney; Continental rift; H-C-O-Ca-Sr-Nd-Pb-Th-U-isotopes; Hydrothermalism. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00206/31762/30172.pdf |
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| Geistdoerfer, P. |
| Seven new fish species have been found so far on the Pacific and Atlantic hydrothermal vents: the synaphobranchid Thermobiotes mytilogeiton; the zoarcid Thermarces cerberus and Pachycara thermophilum; the bythitid Bythites hollisi; the cyclopterid Careproctus hyaleius; one zoarcid fish; and one ophidiid fish. The characteristics of the 70 specimens collected, and their location in French and American museums, are listed. The results and observations made on vent fishes and fishes living around the periphery of the vents observed during recent dives (especially along the East Pacific Rise between 17 and 19 degrees S, the North Fiji Basin Rise and the Mid Atlantic Rise) are summarized. Previous literature on vent fishes is reviewed. |
| Tipo: Text |
Palavras-chave: Hydrothermalism; Deepsea; Fishes; Atlantic Ocean; Pacific Ocean. |
| Ano: 1996 |
URL: http://archimer.ifremer.fr/doc/00096/20724/18361.pdf |
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| Marchand, Michel; Termonia, M; Caprais, Jean-claude; Wybauw, M. |
| During the French-Mexican cruise 'Guaynaut', carried out in November 1991 in the southern depression of the Guaymas Basin (gulf of California), an actively spreading oceanic basin, various samples were collected by means of the submersible 'Nautile'. The on-line coupling of purge and trap to capillary gas chromatography-mass spectrometry (P/T-GC-MS) has been applied to the analysis of volatile organic compounds (VOC) in water, sediments and hydrothermal deposit samples in order to contribute to the characterization of the bacterial microflora activity which is developed on this particular hydrothermal site. The results obtained for alkanes, monoaromatic hydrocarbons and organosulfur compounds lead to successful interpretation in terms of bacterial activity. |
| Tipo: Text |
Palavras-chave: Volatile organic compounds (VOC); Hydrothermalism; Guaymas Basin. |
| Ano: 1994 |
URL: http://archimer.ifremer.fr/doc/00186/29768/28265.pdf |
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| Ondreas, Helene; Cannat, M.; Fouquet, Yves; Normand, Alain; Sarradin, Pierre-marie; Sarrazin, Jozee. |
| We present new high-resolution bathymetry and backscatter data acquired in 2006 with the ROV Victor 6000 over the Lucky Strike hydrothermal field, Mid-Atlantic Ridge. As long-term monitoring of the Lucky Strike area (MoMAR project) is being implemented, these new high-resolution data offer an unprecedented view of the distribution of hydrothermal edifices, eruptive facies, and small-scale tectonic features in the Lucky Strike vent field. We show that vents located in the NW and NE correspond with wide expanses of lumpy seafloor which we interpret as primarily made of broken chimneys and sulfide edifices. They are found above scarps with relief > 50 m or on associated mass wasting deposits. By contrast, the SE and SW vents correspond with small expanses... |
| Tipo: Text |
Palavras-chave: Hydrothermalism; Lava lake; Lucky Strike; Mid Atlantic Ridge. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6161.pdf |
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| Komai, T; Segonzac, Michel. |
| The hydrothermal vent shrimp genus Mirocaris is reviewed. Morphological comparison between the two nominal species in the genus, M. fortunata and M. keldyshi, was made based on the re-examination of the holotype and paratypes of Mirocarisfortunata and the paratypes of M. keldyshi. Samples newly collected from various sites on the Mid-Atlantic Ridge were also examined. The validity of the genus Mirocaris has been confirmed. However, our study has revealed that the supposed morphological characters distinguishing M. fortunata and M. keldyshi do not provide significant taxonomic differences and further comparison failed to detect morphological differences between the two taxa. Thus M. keldyshi is synonymized with M. fortunata, and so there is only one single... |
| Tipo: Text |
Palavras-chave: Hydrothermalism; Mid Atlantic Ridge; Redescription; Synonym; Taxonomy; M. keldyshi; Mirocaris fortunata. |
| Ano: 2003 |
URL: http://archimer.ifremer.fr/doc/2003/publication-883.pdf |
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| Szitkar, Florent; Dyment, Jerome; Choi, Yujin; Fouquet, Yves. |
| High-resolution magnetic surveys acquired near the seafloor show that active basalt-hosted hydrothermal sites are associated with zones of lower magnetization. This observation may reflect the thermal demagnetization of a hot hydrothermal zone, the alteration of basalt affected by hydrothermal circulation, and/or the presence of thick, nonmagnetic hydrothermal deposits. In order to discriminate among these inferences, we acquired vector magnetic data 50 m above inactive hydrothermal site Krasnov using the Remotely Operated Vehicle (ROV) Victor. This deep hydrothermal site, located 7 km east of the Mid-Atlantic Ridge (MAR) axis at 16°38′N, is dissected by major normal faults and shows no evidence of recent hydrothermal activity. It is therefore a perfect... |
| Tipo: Text |
Palavras-chave: Magnetic anomalies; Hydrothermalism; Alteration; Modeling. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00188/29915/28375.pdf |
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