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| Registros recuperados: 10 | |
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| Allenou, Jean-pierre; Renard, Vincent. |
| Scientific and technical report n°37 from Centre Océanologique de Bretagne is devoted to the Sea-Beam, a multi-beam echo-sounder installed on the B.V. JEAN CHARCOT in the spring of 1977. It describes, in general terms, the main characteri stics as well as an evaluation of the performance and potentiel of the system. The Sea-deam is manufactured buy General Instrument Corporation, Westwood, Massachusetts. [NOT CONTROLLED OCR] |
| Tipo: Text |
Palavras-chave: Histoire Ifremer. |
| Ano: 1978 |
URL: http://archimer.ifremer.fr/doc/1978/rapport-4792.PDF |
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| Renard, Vincent; Allenou, Jean-paul. |
| En 1976, le CNEXO a fait l'acquisition d'un sondeur bathymétrique à 16 faisceaux étroits, le Sea-Beam, fabriqué par la Société General Instrument Corporation, Harris Division, Westwood, Massachusetts. Ce sondeur a été installé et testé au printemps 1977 sur le N/O Jean Charcot. Contrairement aux sondeurs classiques qui ne fournissent qu'une ligne de sonde unique, ce nouveau sondeur permet de couvrir, en un seul passage du navire, un couloir dont la largeur égale les 3/4 de la profondeur (4 500 m par des fonds de 6 000 m) [1]. Les données obtenues sont traitées en temps réel par un mini-ordinateur grâce à un logiciel élaboré qui fournit sur une table traçante des lignes de contour bathymétriques à intervalle et à échelle choisis par l'utilisateur. Les... |
| Tipo: Text |
Palavras-chave: Histoire Ifremer. |
| Ano: 1979 |
URL: http://archimer.ifremer.fr/doc/1979/publication-5260.pdf |
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| Renard, Vincent. |
| Surface magnetic anomalies in the Famous area define a typical zebra pattern related to sea floor spreading.This pattern is symmetrical and corresponds to a 1.1 cm/yr half spreading rate up to anomaly 3'. The axis of the central block is off-set from the topographic axis of the rift and indicates either asymmetric spreading in the central zone or a ridge axis jump.These two hypotheses are discussed. [NOT CONTROLLED OCR] |
| Tipo: Text |
Palavras-chave: Histoire Ifremer. |
| Ano: 1976 |
URL: http://archimer.ifremer.fr/doc/1976/publication-5193.pdf |
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| Pautot, Guy; Renard, Vincent; Daniel, Jacques; Dupont, Jacques. |
| The west African continental margin between Abidjan (Ivory Coast) and Walvis Boy (Southwcst Africa) was surveyed in 1971 by the R/V Jean Charcot. Fiftyeight seismic-reflection (flexotir source), bathymetric (3.5 and 12 kc), gravimetric, and magnetic profiles were obtained. The seaward limit of an evaporitic zone outlined during the survey is at the boundary between continental slope and continental rise. Variation of depth of this limit as a function of latitude shows the presence of a large offset at 11°S which seems to be related to an east-east-southeast line of magnetic seamounts cutting into the continental slope. The Annobon-Cameroun volcanic axis separates the salt zones of the Nigerian basin and Congo-Angola basin. The northern limit of Salt... |
| Tipo: Text |
Palavras-chave: Histoire Ifremer. |
| Ano: 1973 |
URL: http://archimer.ifremer.fr/doc/1973/publication-5123.pdf |
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| Avedik, Félix; Renard, Vincent; Buisine, Didier; Cornic, Jean-yves. |
| This paper describes a pop-up ocean bottom seismograph designed primarily for refraction surveys both on the continental shelf and in deep sea. Its development is the extension of our system based on seismic detectors located on the sea floor with radio transmission of seismic signals and used for seismic refraction studies on the continental shelf. The seismic detectors (vertical geophone or hydrophone and two orthogonally mounted horizontal geophones) are located outside of the pressure vessel on the main frame. Optionally, the seismic sensors may be decoupled from the main frame assembly.This decoupling is performed by a mobile arm positioning the separate three component sensor package on the sea floor. [NOT CONTROLLED OCR] |
| Tipo: Text |
Palavras-chave: Histoire Ifremer. |
| Ano: 1978 |
URL: http://archimer.ifremer.fr/doc/1978/publication-5174.pdf |
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| Grevemeyer, I; Renard, Vincent; Jennrich, C; Weigel, W. |
| Bathymetric data from a Hydrosweep multibeam sonar survey of a 720 km long tectonic corridor on the east flank of the southern EPR at 14 degrees 14'S covered about 25,000 km(2) of zero-age to 8.5 m.y. old crust (magnetic anomaly 4A). In this corridor we document a strong correlation of robust along flowline changes in abyssal hill morphology and seamount size distribution with spreading rate changes deduced from our magnetic data. Indeed, we find that both rms height of abyssal hills and abundance and height of seamounts increase significantly as spreading rate changes from similar to 75 mm/yr to over 85 mm/yr (half rate). Moreover, we identified 46 seamounts taller than 100 m. Previous studies on the southern EPR reported a larger density of seamounts,... |
| Tipo: Text |
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| Ano: 1997 |
URL: http://archimer.ifremer.fr/doc/00336/44682/45035.pdf |
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| Mascle, Jean; Renard, Vincent. |
| During the Geobrésil cruise of the R. V. Jean Charcot (1973) several marine geophysical lines, including bathymetry, magnetism, continuous seismic as well as sonobuoy profiles have been run across a deep marginal plateau extending on the southeastern Brazilian margin and known as the Sao Paulo Plateau. These data indicate the presence of a thick sedimentary cover (more than 4s DTT) on the upper slope and up to 3s DTT thick on the lower slope and rise. The entire slope is highly disturbed by salt diapiric structures mostly apparent between the 2 000-3 000 bathymetriclines and comparable to the ones described in the western Mediterranean sea. The Sao Paulo scarp, bordering the deep marginal plateau to the South-West, is believed to be a discontinuous and "en... |
| Tipo: Text |
Palavras-chave: Histoire Ifremer. |
| Ano: 1976 |
URL: http://archimer.ifremer.fr/doc/1976/publication-4990.pdf |
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| Registros recuperados: 10 | |
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