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| Hamelin, Cedric; Dosso, Laure; Hanan, Barry; Barrat, Jean-alix; Ondreas, Helene. |
| Major, trace element and Sr-Nd-Hf isotope data in basalts collected along the Pacific-Antarctic Ridge ( PAR) axis between 53 and 41 S, far from any hotspot influence, reveal tight coherent geochemical variations within the depleted MORB mantle. All samples are located below the Pacific reference line defining two sub-oceanic mantle domains on each side of the Easter microplate. The data extend the PAR 66-53 S field towards more radiogenic Sr (0.70264), less radiogenic Nd (epsilon = 7.7) and Hf (epsilon = 11.4) values. The along ridge geochemical variability is closely related to the morphological segmentation of the ridge. Anomalous geochemical features are attributed to the atypical morphology of two segments due to the presence of off-axis magmatism. The... |
| Tipo: Text |
Palavras-chave: Pacific-Antarctic; Depleted mantle; Sr-Nd-Hf isotopes. |
| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00004/11526/8123.pdf |
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| Boulart, Cedric; Briais, Anne; Chavagnac, Valerie; Revillon, Sidonie; Ceuleneer, Georges; Donval, Jean-pierre; Guyader, Vivien; Barrere, Fabienne; Ferreira, Nicolas; Hanan, Barry; Hemond, Christophe; Macleod, Sarah; Maia, Marcia; Maillard, Agnes; Merkuryev, Sergey; Park, Sung-hyun; Ruellan, Etienne; Schohn, Alexandre; Watson, Sally; Yang, Yun-seok. |
| Using a combined approach of seafloor mapping, MAPR and CTD survey, we report evidence for active hydrothermal venting along the 130°-140°E section of the poorly-known South-East Indian Ridge (SEIR) from the Australia-Antarctic Discordance (AAD) to the George V Fracture Zone (FZ). Along the latter, we report Eh and CH4 anomalies in the water column above a serpentinite massif, which unambiguously testify for ultramafic-related fluid flow. This is the first time that such circulation is observed on an intermediate-spreading ridge. The ridge axis itself is characterized by numerous off-axis volcanoes, suggesting a high magma supply. The water column survey indicates the presence of at least ten distinct hydrothermal plumes along the axis. The CH4:Mn ratios... |
| Tipo: Text |
Palavras-chave: Hydrothermal plumes; Mid-ocean ridges; South-East Indian Ridge. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00387/49821/50400.pdf |
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