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| Registros recuperados: 35 | |
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| Foucher, Jean-paul; Le Pichon, Xavier; Sibuet, Jean-claude. |
| The role of partial melting in the uniform lithospheric stretching model of continental margin formation is explored. It is shown that the transition from continental lithosphere stretching to oceanic accretion is most probably controlled by the production of a significant amount of partial melting in the asthenosphere immediately below the lithosphere, which requires stretching factors larger than 3. It is also shown that, at stretching factors exceeding 2, the law of subsidence is significantly changed by the presence of partial melt in the underlying asthenosphere. The implications for the existence of deep continental margin basins on thinned continental crusts are examined. The Armorican deep continental margin basin is taken as an example. [NOT... |
| Tipo: Text |
Palavras-chave: Histoire Ifremer. |
| Ano: 1981 |
URL: http://archimer.ifremer.fr/doc/1981/publication-5375.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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| 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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| Auzende, Jean-marie; Olivet, Jean-louis; Charvet, J; Le Lann, Alain; Le Pichon, Xavier; Monteiro, Jh; Nicolas, Anne; Ribeiro, A. |
| THE structure and nature of the uppermost oceanic mantle and crust has been, and still is, the subject of a major international research effort . Yet the direct field evidence known to us on this subject, whether obtained by drilling in the I.P.O.D. oceanic crust programme² or by submersible surveying in the Famous programme , has been either very incomplete or limited to the upper part of layer 2. As a result, the problem of the comparison between ophiolites and oceanic crust is still debated . We report here the preliminary results of an in situ geological survey in which we have sampled and observed what we believe to be an almost complete geological section starting a few kilometres below the Moho discontinuity and ending in the upper part of layer 2... |
| Tipo: Text |
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| Ano: 1978 |
URL: http://archimer.ifremer.fr/doc/1978/publication-5230.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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| Francheteau, Jean; Choukroune, P.; Hekinian, Roger; Le Pichon, Xavier; Needman, H.d.. |
| Data from rock-dredging have often been used to infer that oceanic fracture zones provide a 'window' into layers of the oceanic crust lying at a depth below the surface that is approximately equivalent to the vertical offset of the fracture zone, and thus permit the reconstruction of a crustal stratigraphy for the whole of acoustic layer 2 (commonly considered to have an average thickness of ~2 km) and in some interpretations for the upper part of layer 3. Alternatively, it has been suggested that fracture zones are preferential sites of serpentinite mega-dykes differing in composition from layer 3 but containing inclusions of the third layer. The published data indicate that basalts and basaltic rubble are abundant in fracture zones and on analysis do not... |
| Tipo: Text |
Palavras-chave: Histoire Ifremer. |
| Ano: 1976 |
URL: http://archimer.ifremer.fr/doc/1976/publication-5109.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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| Le Pichon, Xavier; Sibuet, Jean-claude. |
| The kinematics of the Eocene episode of compression between the Iberian and European plates is examined. It is proposed that the boundary between the two plates extended West of the Pyrenees, along the Spanish marginal trench to end West of King's trough at a triple point junction. The pole of relative rotation computed within this hypothesis lies near 5°N ; 62°W and the resulting shortening along the Pyrenees is about 50 km dong 45°E. [NOT CONTROLLED OCR] |
| Tipo: Text |
Palavras-chave: Histoire Ifremer. |
| Ano: 1971 |
URL: http://archimer.ifremer.fr/doc/1971/publication-4918.pdf |
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| Le Pichon, Xavier; Sibuet, Jean-claude. |
| It has been proposed that the opening of the Bay of Biscay occurred by rotation about a pole situated near Paris (50.0° N, 3.3° E) and not about the pole proposed by Bullard et al.(4) (43.6° N, 1.0° E). The rotation about the first pole results in strike-slip motion aIong the North Pyrenean fault during the pre-Upper-Cretaceous opening, while the rotation about the second pole results in compression there. The second rotation is not compatible with geological data(5) which indicates extension prior to Upper Cretaceous in the Pyrenean region. We wish to show how these two hypothetical rotations agree with the magnetic data of Williams and McKenzie(6). [NOT CONTROLLED OCR] |
| Tipo: Text |
Palavras-chave: Histoire Ifremer. |
| Ano: 1971 |
URL: http://archimer.ifremer.fr/doc/1971/publication-4898.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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| 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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| 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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| 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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| Bayer, R.; Le Mouel, J.l.; Le Pichon, Xavier. |
| A survey of the southern part of the Balearic Basin was flown in 1971 at a height of 600 m. The results of a survey of the northern part, flown at a height of 3000 m, which was previously published, have been downward continued to a height of 600 m. The resulting composite map shows well defined low amplitude (100 gammas) magnetic lineations of the Vine et Matthews' type offset by fracture zones. The lineated zones are bounded by large quasi-circular anomalies on the edge of possibly "continental" non magnetic zones. The results define a complex kinematic pattern of the opening of the Balearic Basin, in terms of plate tectonics. [NOT CONTROLLED OCR] |
| Tipo: Text |
Palavras-chave: Histoire Ifremer. |
| Ano: 1973 |
URL: http://archimer.ifremer.fr/doc/1973/publication-5064.pdf |
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| Le Pichon, Xavier; Cressard, Alain; Mascle, Jean; Pautot, Guy; Sichler, Bertrand. |
| In 1921 the "Pourquoi pas?" undertook, under the authority of J. Charcot, an identification of the Rockall bank (2). The petrographic nature of this relief was studied by Lacroix (2) who concluded to aegirine granite dated, since then, by Miller (3) and Sabine (4), from the early Tertiary period. At the beginning of the Noratlante cruise, in August 1969, the "J. Charcot" carried out a number of profiles, tallying the Porcupine and the Rockall area (fig.1). In addition to the gravimetry and magnetism recordings, an oblique-reflection profile and six Flexotir seismic-reflection profiles (with a frequency comprised of between 10 and 30 cycles) were carried out. We only present here the first results based on this last technique. |
| Tipo: Text |
Palavras-chave: Histoire Ifremer. |
| Ano: 1970 |
URL: http://archimer.ifremer.fr/doc/1970/publication-4873.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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| Registros recuperados: 35 | |
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