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| Registros recuperados: 35 | |
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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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| Gasperini, Luca; Polonia, Alina; Bortoluzzi, Giovanni; Henry, Pierre; Le Pichon, Xavier; Tryon, Michael; Cagatay, Namik; Geli, Louis. |
| An open problem concerning the Mw 7.4, 1999 Izmit earthquake along the North Anatolian Fault (NAF) system is the apparent conflict between estimates of strike-slip deformation based on field and remote sensing data. This is due to the fact that the main strand of the NAF west of the epicenter lies below the Sea of Marmara. Seismological evidence and models based on synthetic aperture radar interferometry suggest that coseismic and early postseismic displacement accumulated after the earthquake could have reached the western end of the Izmit Gulf and possibly the southern edge of the Cinarcik Basin, tapering off along the northern coast of the Armutlu Peninsula, more than 60 km from the epicenter. This scenario is not confirmed by onshore field observations... |
| Tipo: Text |
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| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00031/14256/12205.pdf |
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| Le Pichon, Xavier. |
| Plate tectonics gave a great stimulus to marine geology and geophysics; in the years since its enunciation there have been major drilling programmes, a new science of global palaeoenvironmental oceunography and much more detailed oceanographic surveYs. The pace shows no sign of slackening-in the next few years the passive continental margins will be muchstudied. [NOT CONTROLLED OCR] |
| Tipo: Text |
Palavras-chave: Histoire Ifremer. |
| Ano: 1977 |
URL: http://archimer.ifremer.fr/doc/1977/publication-5206.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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| 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 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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| 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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| Biju-duval, B.; Dercourt, J.; Le Pichon, Xavier. |
| We propose a series of paleogeographic maps of the western alpine system, from Triassic to Present, based on the geologic structure and evolution of the mediterranean,its adjacent folded belts and the associated basins, and on the evolution of the North Atlantic ocean according to the magnetic anomaly informations. The kinematic framework is relatively precise for the Cenozoic but the accuracy is quite poorer for the Mesozoic.Between Triassic and Upper Cretaceous,the reconstructed continental margins can be compared to present passive or active margins.The geologic evolution can be described in terms of plate tectonics. After Upper Cretaceous, the oceanic areas are quite limited and the geologic evolution is dominated by the continental collision... |
| Tipo: Text |
Palavras-chave: Histoire Ifremer. |
| Ano: 1977 |
URL: http://archimer.ifremer.fr/doc/1977/publication-5197.pdf |
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| Le Pichon, Xavier. |
| The success of what can now be called, since the Joides drillings, the F.J. Vine and D.H. Matthews theory lead to the formulation of a hypothesis giving way to a kinematic description of the current tectonic activity on the surface of the earth. This hypothesis, the plate tectonic, admits that the orogenic areas, where most of the mechanical energy vanishes, are the areas where the differential horizontal motions between rigid lithospheric plates occurs. 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. |
| Tipo: Text |
Palavras-chave: Histoire Ifremer. |
| Ano: 1970 |
URL: http://archimer.ifremer.fr/doc/1970/publication-5027.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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| 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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| Le Pichon, Xavier. |
| Le colloque s'est réuni au Centre Océanologique de Bretagne les 3 et 4 février 1972 à l'invitation du Comité de l'Action Thématique Programmée "Géodynamique de la Méditerranée Occidentale et de ses bordures" de l'Institut National d'Astronomie et Géophysique. Cette A.T.P., organisée par l'INAG pour la période 1971-1975 dans le cadre du VIe Plan, a pour but principal l'étude des mécanismes qui ont dominé l'évolution post-mésozoïque de la région correspondant à la Méditerranée occidentale actuelle et aux continents qui l'entourent, l'accent étant mis sur les mécanismes de déformations actuelles. Le thème de recherche devrait permettre de réunir les chercheurs des diverses disciplines des sciences de la terre sur un sujet commun, amorçant ou accentuant la... |
| Tipo: Text |
Palavras-chave: Histoire Ifremer. |
| Ano: 1972 |
URL: http://archimer.ifremer.fr/doc/1972/publication-5071.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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| 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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| 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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| Registros recuperados: 35 | |
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