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Registros recuperados: 35 | |
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Melguen, Marthe; Le Pichon, Xavier; Sibuet, Jean-claude. |
A schematic model of the evolution of the South Atlantic paleoenvironment since the early Cretaceous is proposed. The reconstruction here proposed is based on all the data offered for the South Atlantic by the Deep-Sea Drilling Project. These data are integrated within the framework of Plate Tectonics. The emphasis is put on the methodology available to reconstruct the ocean crust morphology and its sedimentary cover throughout the opennig of the ocean. Paleobathymetric, paleocirculation and paleofacies maps are presented. The paleofacies maps are in great part based on a new paleo-CCD (paleo-calcite compensation depth) curve, which is tentatively proposed here for the South Atlantic. During the early Cretaceous the South Atlantic consisted of two narrow... |
Tipo: Text |
Palavras-chave: Histoire Ifremer. |
Ano: 1978 |
URL: http://archimer.ifremer.fr/doc/1978/publication-5234.pdf |
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Le Pichon, Xavier; Melguen, M.; Sibuet, Jean-claude. |
A schematic model of the evolution of the South Atlantic ocean is proposed to demonstrate the possibilities offered by the Deep Sea Drilling Project within the framework of Plate Tectonics to reconstruct a logical evolution of the history of the ocean basins and their paleoenvironment. The emphasis is put on the methodology available to reconstruct the ocean crust morphology and its sedimentary cover at all stages throughout the opening of the ocean.Paleobathymetric, deep paleo-water-circulation and paleo-sedimentary - facies maps at five different stages of the opening are presented and discussed. The last type of maps are in great part based on a new paleo - Carbonate Compensation Depth Curve for the South Atlantic which is tentatively proposed here.... |
Tipo: Text |
Palavras-chave: Histoire Ifremer. |
Ano: 1978 |
URL: http://archimer.ifremer.fr/doc/1978/publication-5196.pdf |
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Choukroune, Pierre; Le Pichon, Xavier; Seguret, Michel; Sibuet, Jean-claude. |
The different hypotheses proposed for the creation of the Bay of Biscay are reviewed. New geological and geophysical data collected in the last two years in the Bay and in the Pyrenean domain give new insight into the tectogenesis of the Pyrenees. Geological data of the Pyrenean area provide tight constraints on the hypothesis of formation of the Bay. The most probable hypothesis is an opening by rotation of the Iberian Peninsula around a pole of rotation situated near Paris, which resulted in strike-slip motion dong the North Pyrenean fault during the Upper Mesozoic. A progressive westward migration of the pole initiated in the late Cretaceous blocked the motion dong the fault and led to the main Eocene tectogenetic Pyrenean phase. [NOT CONTROLLED OCR] |
Tipo: Text |
Palavras-chave: Histoire Ifremer. |
Ano: 1973 |
URL: http://archimer.ifremer.fr/doc/1973/publication-5061.pdf |
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Bellaiche, G.; Cheminee, J.l.; Francheteau, Jean; Hekinian, Roger; Le Pichon, Xavier; Needham, H.d.; Ballard, R.d.. |
THE Rift Valley of the Mid-Atlantic Ridge, within which lies a segment of the accreting plate boundary between Africa and North America, is well defined between 36°40'N and 36°55' N. It is about 30 km wide and 1.5 km deep in that area (Fig. 1). This small portion of the rift, WSW of the Azores, was chosen as the primary target of the French-American Mid-Oceanic Undersea Survey (FAMOUS) programme, and many surface ship studies have heen conducted already. We report here preliminary results of seven dives into the deepest part of the Rift Valley that were made by the bathyscaphe Archimède during the summer of 1973. [NOT CONTROLLED OCR] |
Tipo: Text |
Palavras-chave: Histoire Ifremer. |
Ano: 1974 |
URL: http://archimer.ifremer.fr/doc/1974/publication-5443.pdf |
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Olivet, Jean-louis; Sichler, Bertrand; Thonon, Pierre; Le Pichon, Xavier; Martinais, Guy; Pautot, Guy. |
The Gibbs fracture moves the central Rift of the Mid-Atlantic Ridge 370 km to the left at latitude 53O north. It is the only fracture located between Europe and America that can be compared to the large equatorial fractures mapped by B.C. Heezen and M. Tharp between Africa and America. Its morphology is a major element in the understanding of the structural framework of the northern Atlantic Ocean. The identification of its extension to the west was one of the proposed focuses for the first Noratlante expedition of the R.V. Jean-Charcot (conducted in August 1969 under the authority of the C.N.E.X.O.). J.T. Wilson (2) suggested, in his hypothesis of sea-bed spreading from the dorsal axis, that such fractures are "transforming faults" that are active only... |
Tipo: Text |
Palavras-chave: Histoire Ifremer. |
Ano: 1970 |
URL: http://archimer.ifremer.fr/doc/1970/publication-4875.pdf |
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Angelier, Jacques; Auboin, Jean; Bellaiche, Gilbert; Blanchet, René; De Charpal, Olivier; Irr, France; Le Pichon, Xavier. |
The results of 14 aives made with the submersible Cyana in the lower parts of the Stoechades and Saint-Tropez canyons, between 2,400 and 1,500 m, are compatible with the following geological history of the French Mediterranean margin: a thick terrigeneous sedimentary series was deposited near the Oligo-Miocene transition; the canyons were eroded subaerially within this series during the Messinian; the morphology of the canyons has been maintained since by active bottom currents and gravity tectonics on the bordering cliffS. [NOT CONTROLLED OCR] |
Tipo: Text |
Palavras-chave: Histoire Ifremer. |
Ano: 1977 |
URL: http://archimer.ifremer.fr/doc/1977/publication-5198.pdf |
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Le Borgne, Eugéne; Le Pichon, Xavier. |
The results of a precise and homogeneous aeromagnetic survey covering the Bay of Biscay, France, and the North Western Mediterranean are presented. The results suggest that the Bay of Biscay and the Mediterranean basin were created since the Triassic by drift of the adjacent continents. Indications are given about the times and geometries of opening of these basins. The implications of these results on the Mesozoic and Cenozoic tectonic history of South-Western Europe are important. [NOT CONTROLLED OCR] |
Tipo: Text |
Palavras-chave: Histoire Ifremer. |
Ano: 1971 |
URL: http://archimer.ifremer.fr/doc/1971/publication-4919.pdf |
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Olivet, Jean-louis; Le Pichon, Xavier; Laubier, Lucien. |
The cold waters from the Norwegian Sea are the main source of the underflow system in the northern Atlantic Ocean (10) (pl. 1, fig. 1b). The role of these currents in the formation of large sediment ripples has been demonstrated in some recent studies [(2), (3)]. As in the southern Atlantic Ocean, the observations suggested that their influence had been of importance since the Eocene era (6). From a sedimentological point of view, it appears that the Gibbs fracture (4) represents a very important feature in this system; this structure both forms a deep opening through the Mid-Atlantic Ridge and a dam across the abyssal plain to the northeast of Newfoundland. This dam, which is still active today, though partly flooded, must have been continuous from the... |
Tipo: Text |
Palavras-chave: Histoire Ifremer. |
Ano: 1970 |
URL: http://archimer.ifremer.fr/doc/1970/publication-4882.pdf |
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Le Pichon, Xavier. |
L'exploration de la couverture sédimentaire des fonds océaniques n'a été possible d'une manière systématique que depuis 1960, lorsque les techniques de sismique réflexion continue furent introduites pour la première fois. L'absorption du son dans les sédiments étant d'autant plus grande que la fréquence est élevée, les procédés de sondage ultra-sonore classiques qui utilisent des fréquences de l'ordre de 12 kHz ne permettent pas des pénétrations supérieures à quelques mètres à l'intérieur des sédiments meubles. Par contre, aux fréquences de l'ordre de 100 Hz, la pénétration de l'onde sonore est beaucoup plus grande et il devient possible d'effectuer un véritable sondage continu des couches sédimentaires consolidées. [OCR NON CONTRÔLE] |
Tipo: Text |
Palavras-chave: Histoire Ifremer. |
Ano: 1973 |
URL: http://archimer.ifremer.fr/doc/1973/publication-5022.pdf |
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Francheteau, Jean; Le Pichon, Xavier. |
A plate tectonic model of the early opening of the south atlantic is used to des cibe the structural framework of the continental margins and adjacent oceanic and coastal areas on both sides of the ocean. It is proposed that major offsets of the continental margins necessarily induce the subsidence of coastal basins where fracture zones intersect the continents. The configuration of the accreting plate-margin boundary gradually developed throughout the opening of the ocean after Late Jurassic time. [NOT CONTROLLED OCR] |
Tipo: Text |
Palavras-chave: Histoire Ifremer. |
Ano: 1972 |
URL: http://archimer.ifremer.fr/doc/1972/publication-5033.pdf |
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Pautot, Guy; Le Pichon, Xavier. |
En nous appuyant sur les 13 rapports initiaux, publiés à ce jour, et sur les résultats sommaires des 15 autres parcours du bâtiment foreur "Glornar Challenger", nous présentons quelques aspects importants des principaux résultats acquis. Un jeu de cartes synthétiques est d'abord présenté : âge du substratum ou des sédiments les plus anciens atteints et, pour comparaison, cartes des isochrones du socle d'aprés les anomalies magnétiques. Ces documents sont établis à partir des diverses données publiées, souvent préliminaires, et que nous n'avons pas cherché à réconcilier dans le cas où des désaccords existaient. La même remarque s'applique d'ailleurs à l'ensemble de l'article. Nous attirons ensuite l'attention sur quelques aspects qui nous paraissent... |
Tipo: Text |
Palavras-chave: Histoire Ifremer. |
Ano: 1973 |
URL: http://archimer.ifremer.fr/doc/1973/publication-5150.pdf |
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Henry, Pierre; Tryon, Mike; Bourlange, Sylvain; Geli, Louis; Zitter, Tiphaine; Bouloubassi, Ioanna; Burnard, Pete; Cagatay, M Namik; Chevalier, Nicolas; Gasperini, Luca; Gorur, Naci; Gerigk, Christoph; Leveque, Claude; Le Pichon, Xavier; Lopez-garcia, Purification; Massol, Alain; Mercier De Lepinay, Bernard; Natalin, Boris; Ozeren, Sinan; Pierre, Catherine; Ritt, Benedicte; Sengor, Am Celal; Ucarkus, Gulsen. |
Tipo: Text |
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Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/00398/50962/51714.pdf |
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Foucher, Jean-paul; Le Pichon, Xavier. |
Sleep (1971) has presented some very interesting observations on the exponential decrease of the subsidence rate in coastal basins. He shows that the time constant of this exponential decrease is of the same order of magnitude that the thermal time constant of a lithospheric plate. He then makes calculations with a physical model combining erosion and thermal contraction. The purpose of these comments is to show that his physical assumptions are invalid and that çonsequently his calculations are grossly in error. [NOT CONTROLLED OCR] |
Tipo: Text |
Palavras-chave: Histoire Ifremer. |
Ano: 1972 |
URL: http://archimer.ifremer.fr/doc/1972/publication-5041.pdf |
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Le Pichon, Xavier. |
The plate tectonic hypothesis admits that the orogenic areas, where most of the mechanical energy vanishes, are the areas where the differential horizontal motions between rigid lithospheric plates occur. The success of this hypothesis relies on the fact that the aseismic deformations inside the plates are less important than the motions occurring along the seismic areas. The rigidity of the plates enables a rigorous analysis of their kinematic. This quantitative model of the evolution of the Earth is an incredible revolution in earth science. It leads to a series of new scientific processes and research involving every different field belonging to earth science. |
Tipo: Text |
Palavras-chave: Histoire Ifremer. |
Ano: 1970 |
URL: http://archimer.ifremer.fr/doc/1970/publication-4887.pdf |
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Sibuet, Jean-claude; Le Pichon, Xavier; Goslin, Jean. |
THE evolution of a lithospheric plate, as it migrates away from the accreting boundary (mid-ocean ridge crest), is mostly a result of vertical cooling by conduction. As density is a function of temperature and pressure, the density structure should be a function of the age of the plate and, in order to preserve isostatic equilibrium, the seafloor should subside as the plate cools. Thus, the variation of heat flow, seafloor depth and the gravity field are different expressions of the same process, progressive cooling, occurring over the whole thickness of the plate. Sclater and Francheteau² have verified these properties through an analysis of the variation of heat flow and depth with the age of the plate. Their model assumed that the plate remains a... |
Tipo: Text |
Palavras-chave: Histoire Ifremer. |
Ano: 1974 |
URL: http://archimer.ifremer.fr/doc/1974/publication-5430.pdf |
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Le Pichon, Xavier; Pautot, Guy; Weill, J.p.. |
The Alboran Sea contains two basins deeper than 1,000 m separated by a ridge which we shall call the Alboran marginal fracture (Fig. 1). Seismic reflexion studies and data from the Joides drill site 121, situated exactly on the northern limit of the western basin, show that the deepest sedimentary layers, lying on the substratum, are older than upper Burdigalian (14 m.y.), but probably younger than lower Aquitanian (23 m.y.)1. But we do not know whether the substratum of the deep basins is young oceanic crust or foundered continental crust. Here we shall assume that the portions of the basins deeper than 1,000 m indeed consist of new surface created by the separation of two rigid plates during the Middle Miocene, and we shall discuss whether the... |
Tipo: Text |
Palavras-chave: Histoire Ifremer. |
Ano: 1972 |
URL: http://archimer.ifremer.fr/doc/1972/publication-5043.pdf |
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Le Pichon, Xavier; Hekinian, Roger; Francheteau, Jean; Carre, Daniel. |
IN OCTOBER 1972, the bathyscaphe Archimède made a series of training dives-to a 2600-m water-depth off northwest Corsica in order to test new equipment.Two of these dives (72-5 and 72-7) were made at the limit of the lower continental slope and the abyssal plain near an acoustic transponder (X'4 in Fig. 1) with respect to which the submersible could position itself with an accuracy of 10 to 200 m within a radius of 1450 m. The position of X'4 with respect to the geographic grid is not known to better than 200 to 300 m. We feel, however, that the position of the transponder shown on Fig. 1 leads to a good agreement with the relief revealed by the bathymetric map. These dives, in spite of technical shortcomings, gave some unexpected information about the... |
Tipo: Text |
Palavras-chave: Histoire Ifremer. |
Ano: 1975 |
URL: http://archimer.ifremer.fr/doc/1975/publication-5452.pdf |
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Pautot, Guy; Le Pichon, Xavier. |
Deep seismic reflexion surveys have revealed diapiric structures in deep water off Labrador, Newfoundland, Mauritania, Morocco, Portugal, Spain and lreland as well as in the Mediterranean. Many of these diapirs are similar to the Gulf of Mexico salt domes, and it is suggested that there is a continuous deep sea sait layer, off the continental margin, which is related to the early phase of rifting. [NOT CONTROLLED OCR] |
Tipo: Text |
Palavras-chave: Histoire Ifremer. |
Ano: 1970 |
URL: http://archimer.ifremer.fr/doc/1970/publication-4874.pdf |
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Lin, Jing-yi; Le Pichon, Xavier; Rangin, Claude; Sibuet, Jean-claude; Maury, Tanguy. |
In July 2005, about 6 months after the 2004 great Sumatra-Andaman earthquake, 20 ocean bottom seismometers were deployed in the northern Sumatra area. More than 1000 events were identified during the 12 day recording period. After relocation, the seismicity shows different patterns on each side of the Lower Splay Fault. East of this feature and beneath the Aceh basin and fore arc, the deep earthquakes outline the subduction megathrust fault. West of it, the aftershocks distribution is strongly influenced by the active N-S oceanic fracture zones of the subducted plate. Two N-S trending clusters of 10- to 50-km-deep earthquakes observed below the lower wedge are interpreted as reactivated oceanic fracture zones. The postseismic activity suggests a... |
Tipo: Text |
Palavras-chave: 2004 great Sumatra Andaman earthquake; Sumatra trench; Andaman trench; Aftershocks; Splay faults; Oblique subduction. |
Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/00000/11081/7419.pdf |
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Registros recuperados: 35 | |
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