Consulta: creatorFacets:"Le Pichon, Xavier"
Registros recuperados: 35
Data/hora: 15/06/2024 09:13:13

The ocean-continent transition in the uniform lithospheric stretching model : role of partial melting in the mantle
Provedor de dados: 5
Autores: 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

La tectonique des plaques
Provedor de dados: 5
Autores: 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

Structure et évolution des fonds océaniques. La tectonique des plaques
Provedor de dados: 5
Autores: 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

Sampling and observation of oceanic mantle and crust on gorringe bank
Provedor de dados: 5
Autores: 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
Ano: 1978
URL: http://archimer.ifremer.fr/doc/1978/publication-5230.pdf

Résultats scientifiques du programme Joides
Provedor de dados: 5
Autores: 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

Le banc de Gorringe : résultats de la campagne Cyagor (août 1977)
Provedor de dados: 5
Autores: Auzende, Jean-marie; Charvet, Jacques; Le Lann, Alain; Le Pichon, Xavier; Monteiro, José Hippolyte; Nicolas, Adolphe; Olivet, Jean-louis; Ribeiro, Antonio.
Gorringe bank is one of the structures which are found on the Europe-Africa plate boundary. It is located between Tagus abyssal plain in the North and Horseshoe plain in the South. It is oriented NE-SW and is in the exact prolongation of the large "tardi-hercynien" fractures which cross the iberian peninsula and its continental margin. Gorringe bank show two summits just under the sea levels, separated by a saddle. [NOT CONTROLLED OCR]
Tipo: Text
Palavras-chave: Histoire Ifremer.
Ano: 1979
URL: http://archimer.ifremer.fr/doc/1979/publication-5386.pdf

Oceanic fracture zones do not provide deep sections in the crust
Provedor de dados: 5
Autores: 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

Bay of biscay and Pyrenees
Provedor de dados: 5
Autores: 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

Western extension of boundary between european and iberian plates during the pyrenean orogeny
Provedor de dados: 5
Autores: 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

Comments on the evolution of the north-east atlantic
Provedor de dados: 5
Autores: 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

Comments on 'Thermal Effects of the Formation of Atlantic Continental Margins by Continental Break up' by N.H. Sleep
Provedor de dados: 5
Autores: 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

Spatial aftershock distribution of the 26 December 2004 great Sumatra-Andaman earthquake in the northern Sumatra area
Provedor de dados: 5
Autores: 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

La méditerranée occidentale depuis l'oligocène, schéma d'évolution
Provedor de dados: 5
Autores: Le Pichon, Xavier; Pautot, Guy; Auzende, Jean-marie; Olivet, Jean-louis.
The evolution of the Western Mediterranean basin during Tertiary time is discussed. It is proposed that it was created by a continental drift process during Middle Oligocene time, synchronously with the creation of the grabens over the continents. The significance of the Messinian evaporitic sedimentary episode is discussed in liaison with the problem of large scale subsidence which has been at least six kilometers since Oligocene time. [NOT CONTROLLED OCR]
Tipo: Text
Palavras-chave: Histoire Ifremer.
Ano: 1971
URL: http://archimer.ifremer.fr/doc/1971/publication-4921.pdf

MARNAUT 2017. Dive report
Provedor de dados: 5
Autores: 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
Ano: 2007
URL: http://archimer.ifremer.fr/doc/00398/50962/51714.pdf

Aeromagnetic survey of south-western europe
Provedor de dados: 5
Autores: 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

Magnetic anomaly pattern in the western mediterranean
Provedor de dados: 5
Autores: 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

Structures sous-marines des bassins sédimentaires de Porcupine et de Rockall
Provedor de dados: 5
Autores: 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

L'océanographie en temps réel
Provedor de dados: 5
Autores: Le Pichon, Xavier.
La Terre est maintenant considérée comme un ensemble interactif dans lequel l'atmosphère, l'hydrosphère, la biosphère et la lithosphère, entendue au sens large et comprenant croûte, manteau et noyau, forment un système transitoire complexe gouverné par des constantes de temps très variables.
Tipo: Text
Ano: 1992
URL: http://archimer.ifremer.fr/doc/1992/publication-7459.pdf

Marginal fracture zones as Structural framework of continental margins in south atlantic ocean
Provedor de dados: 5
Autores: 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

Rigid plate accretion in an inter-arc basin : mariana trough
Provedor de dados: 5
Autores: Le Pichon, Xavier; Francheteau, Jean; Sharman Iii, George F.
It is verified that an oblique rigid opening results in good fit of the rifted portions of arc on each side of the Mariana trough. The good fit suggests that there has been rigid plate accretion and that a plate 200km wide and 1500 km long can stay undeformed between active consuming and accreting plate boundaries. [NOT CONTROLLED OCR]
Tipo: Text
Palavras-chave: Histoire Ifremer.
Ano: 1975
URL: http://archimer.ifremer.fr/doc/1975/publication-5446.pdf

La faille transformante Gibbs entre le Rift et la marge du Labrador
Provedor de dados: 5
Autores: 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

How far did the surface rupture of the 1999 Izmit earthquake reach in Sea of Marmara?
Provedor de dados: 5
Autores: 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
Ano: 2011
URL: http://archimer.ifremer.fr/doc/00031/14256/12205.pdf

1967-77: ten years of marine geology and geophysics
Provedor de dados: 5
Autores: 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

Thickness of lithosphere deduced from gravity edge effects across the Mendocino Fault
Provedor de dados: 5
Autores: 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

Etude par submersible des canyons des Stoechades et de Saint-Tropez
Provedor de dados: 5
Autores: 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

Opening of the Alboran Sea
Provedor de dados: 5
Autores: 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

Inner floor of the Rift Valley : first submersible study
Provedor de dados: 5
Autores: 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

From the tethys ocean to the mediterranean seas: a plate tectonic model of the evolution of the western alpine system
Provedor de dados: 5
Autores: 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

Cinématique de la tectonique des plaques
Provedor de dados: 5
Autores: 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

Continuous Deep Sea Salt Layer along North Atlantic Margins related to Early Phase of Rifting
Provedor de dados: 5
Autores: 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

Submersible study of lower continental slope-abyssal plain contact
Provedor de dados: 5
Autores: 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

Propositions d'orientation de recherche résultat du Colloque " Géodynamique de la Méditerranée occidentale"
Provedor de dados: 5
Autores: 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

A schematic model of the evolution of the south atlantic
Provedor de dados: 5
Autores: 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

La fracture Gibbs et la circulation profonde en Atlantique Nord
Provedor de dados: 5
Autores: 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

Paléoenvironnement de l'Atlantique sud
Provedor de dados: 5
Autores: 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