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| Francheteau, Jean; Needham, H.d.; Choukroune, P.; Juteau, T.; Seguret, M.; Ballard, R.d.; Fox, J.p.; Normark, W.r.; Carranza, A.; Cordoba, D.; Guerrero, J.; Rangin, C.. |
| A submersible study has been conducted in February - March 1978 at the axis of the East Pacfic Rise near 21°N. The expedition CYAMEX, the first submersible program to be conducted on the East Pacific Rise, is part of the French-American-Mexican project RiTA (Rivera-Tamayo), a 3-year study devoted to detailed geological and geophysical investigations of the East Pacific Rise Crest. On the basis of the 15 dives made by CYANA in the axial area of the Rise, a morphological and tectonic zonation can be established for this moderately-fast spreading center. A narrow, 0.6 to 1.2 km wide zone of extrusion (zone 1), dominated by young lava flows, is flanked by a highly fissured and faulted zone of extension (zone 2) with a width of 1 to 2 km. Further out, zone... |
| Tipo: Text |
Palavras-chave: Histoire Ifremer. |
| Ano: 1980 |
URL: http://archimer.ifremer.fr/doc/1980/publication-5332.pdf |
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| Francheteau, Jean; Juteau, T.; Rangin, C.. |
| Observations of peculiar volcanic objects, made by a submersible on the deep sea floor at a depth of about 2.600 m at and near the axis of the East Pacific Rise during the CYAMEX expedition as part of the RITA Project are presented here. Two basic types of flow forms were observed within the crestal area of the East Pacitic Rise : pillow flows and fluid lavas, the latter sometimes overlying massive flows. The East Pacific Rise at 21°N comprises an axial, unfaulted extrusion zone bordered by an extension zone chararterised by faulting. Pillow flows occupy the innermost or extrusion zone and constitute small elongated volcanic highs. [NOT CONTROLLED OCR] |
| Tipo: Text |
Palavras-chave: Histoire Ifremer. |
| Ano: 1979 |
URL: http://archimer.ifremer.fr/doc/1979/publication-5395.pdf |
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| Francheteau, Jean; Needham, H.d.; Choukroune, P.; Juteau, T.; Seguret, M.; Ballard, R.d.; Fox, P.j.; Normark, W.; Carranza, X; Cordoba, D.; Guerrero, J.; Rangin, C.; Bougault, Henri; Cambon, Pierre; Hekinian, Roger. |
| Massive ore-grade zinc, copper and iron sulphide deposits have been found at the axis of the East Pacific Rise.Although their presence on the deep ocean-floor had been predicted there was no supporting observational evidence. The East Pacific Rise deposits represent a modern analogue of Cyprus-type sulphide ores associated with ophiolitic rocks on land.They contain at least 29% zinc metal and 6% metallic copper.Their discovery will provide a new focus for deep-sea exploration, leading to new assessments of the concentration of metals in the upper layers of the oceanic crust. [NOT CONTROLLED OCR] |
| Tipo: Text |
Palavras-chave: Histoire Ifremer. |
| Ano: 1979 |
URL: http://archimer.ifremer.fr/doc/1979/publication-5278.pdf |
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| Rangin, C.; Francheteau, Jean. |
| Manned submersible observations on a transect from the axis of the East Pacific Rise (21°N) to the area of the Brunhes-Matuyama magnetic inversion were made during the Cyamex and Rise diving phases of the Rita project. In the northern part of the study area, axial, linear. 400 to 600 m-wide topographic highs are formed by relatively unfaulted fresh pillow-lava-flows (zone 1). Flanking the axis of recent volcanism is a 1,200 to 1.500 m-wide zone of highly fractured volcanic hilly terrain that represents the main region of extension as expressed on the surface (zone 2). In the southern part of the study area, the volcanic highs of zones 1 and 2 are flooded by fluid lava flows forming a gentle topography. In both areas, this central part of the Rise is... |
| Tipo: Text |
Palavras-chave: Histoire Ifremer. |
| Ano: 1981 |
URL: http://archimer.ifremer.fr/doc/1981/publication-5330.pdf |
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