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| Registros recuperados: 18 | |
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| Auffret, Gérard-andré; Pastouret, Léo. |
| The evolution of the sedimentary regime that prevailed on the Armorican margin from Late Cretaceous to late Tertiary is herein discussed and interpreted. The sedimentation budget of four components of the sediment : calcium carbonate, quartz, "less than 10 m non carbonate material,"and biogenic silica are quantified as is the composition of the coarse fraction and the textural properties of the sediment. Variation of the coarse fraction components is directly related to change in the oceanic environment (terrigenous supplies, productivity, calcium carbonate dissolution). Sediment texture is a function of many factors, comprising lithology, dissolution action, and hydrodynamic control. The medians of the silt fractions from bulk and decalcified sediments... |
| Tipo: Text |
Palavras-chave: Histoire Ifremer. |
| Ano: 1979 |
URL: http://archimer.ifremer.fr/doc/1979/publication-5256.pdf |
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| Auffret, Gérard-andré; Douville, Jean-luc. |
| The "Pierre Noire" accumulation (20 m depth) is mostly made up of biogenic sands. The bathymetric map as well as some seismic profiles show an irregular morphology in relation with the paleozoic basement. Fourty grab samples were collected within a regular grid. The particle size distributions show that the local variability is low. They allow also to distinguish two fractions characterized by particles of different nature. Long term bottom current measurements show a westward residual component. [NOT CONTROLLED OCR] |
| Tipo: Text |
Palavras-chave: Histoire Ifremer. |
| Ano: 1974 |
URL: http://archimer.ifremer.fr/doc/1974/publication-5432.pdf |
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| Auffret, Gérard-andré; Pastouret, Léo. |
| Knowledges concerning the nature and distribution of present day sedimentary facies on the slope and in the Biscay abyssal plain are very poor, due to the scarcity of available sea-floor samples.Samples from the uppermost section of Reineck cores obtained in six areas of the Bay of Biscay in water depths ranging from 2,000 to 4,800 m allow us to study the evolution of the sediments according to the water depth and geographic localisation.This study suggests that the sediment from the southern part of the bay independently of depth are characterized by a higher amount in terrigenous components (quartz, clay ...).This disparity is explained by the differing phyisiographic setting (broad shelf in the northern part versus narrow shelf and submarine canyon... |
| Tipo: Text |
Palavras-chave: Histoire Ifremer. |
| Ano: 1977 |
URL: http://archimer.ifremer.fr/doc/1977/publication-5201.pdf |
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| Pastouret, Léo; Masse, Jean-pierre; Philip, Jean; Auffret, Gérard-andré. |
| During the Secondary and Tertiary periods, the northern continental margin of the Bay of Biscay was the scene of some subsidence phenomena which lowered the continental blocks through faults. This was mainly observed off the coast of Brittany and at the entrance of the English Channel [(2), (3)]. During the Géogas cruise of the research vessel "Jean-Charcot" (October 1972), samples were taken from the Mériadzek scarp which forms one of these blocks. A dredging conducted on the southern limb of this structure (pl.) enabled the sampling of some sedimentary rocks among which some fragments of a yellow limestone containing a fauna of rudists could be found. |
| Tipo: Text |
Palavras-chave: Histoire Ifremer. |
| Ano: 1974 |
URL: http://archimer.ifremer.fr/doc/1974/publication-5435.pdf |
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| Auffret, Gérard-andré; Zaragosi, S; Voisset, Michel; Droz, Laurence; Loubrieu, Benoit; Pelleau, Pascal; Savoye, R; Bourillet, Jean-francois; Baltzer, Agness; Bourquin, S; Dennielou, Bernard; Coutelle, Alain; Weber, N; Floch, Gilbert. |
| During the SEDIFAN 1 cruise we surveyed the bathymetry and the acoustic properties of the surface sediment of the Celtic Deep Sea Fan. We also collected Kullenberg cores in order to study recent sedimentary processes. From the bathymetry survey it is relatively easy to recognize the main areas of modern fan. The upper fan included a large sedimentary ridge which constitutes the right levee of the prominent meandering Whittard valley. After its confluence with the Shamrock valley the course of the Whittard valley is abruptly deflected to the south. At a short distance to the south the valley divides into two upper-fan channels, the Celtic channel to the west being the deeper one. This point constitutes the centre of a radiating pattern which is developed on... |
| Tipo: Text |
Palavras-chave: Paléoclimat; Turbidité; Sédiment; Quaternaire; Eventail profond; Palaeoclimate; Turbidity; Sediment; Quaternary; Deep sea fan. |
| Ano: 2000 |
URL: http://archimer.ifremer.fr/doc/2000/publication-525.pdf |
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| Auffret, Gérard-andré; Auzende, Jean-marie; Gennesseaux, M.; Monti, S.; Pastouret, Léo; Pautot, G.; Vanney, J.r.. |
| On October 19, 1979 off Nice, the upper continental shelf has been affected by a catastrophic event (Gennesseaux et al., 1980). (a) At 2 p.m. (approximate time), following a lowering of the sea level, a tsunami of several meters amplitude reached the Coast line south of Antibes. This was followed during 4 hours by several oscillations of decreasing amplitude, that were felt on a shore length of about 100 km. (b) About the same time, an embanked area 300 m long and wide, collapsed in a few seconds ; after the event the sea-floor in that area was found at a depth of 50 meters. (c) At 17h45 TU and 22h00 TU, two telephone cables have been broken 80 and 110 km off Nice respectively (fig. 1). (d) No earthquake was registered by the Monaco Observatory during this... |
| Tipo: Text |
Palavras-chave: Histoire Ifremer. |
| Ano: 1980 |
URL: http://archimer.ifremer.fr/doc/1980/publication-5354.pdf |
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| Auffret, Gérard-andré; Berthois, L.; Allen, G. P.; Douville, J. L.. |
| The conditions of sediments transfert from a river medium to a sea medium may be used as guide for forecasting the industrial effluents diffusion. The investigation on river suspensions carried down to the sea shows that clay is the essential component, the maximum size of suspensed particles transfered down stream being very close to 500 microns. Within an estuary, the carried down suspended particles undergo a temporary storage and a mineralogical selection ; a certain amount of the river sediments is finally drained towards the open sea, but it is not possible to erclude the ability of the smallest sediments from the continental table-land to supply the estuary sedimentation. According to the continental table-land morphology, the suspended particles... |
| Tipo: Text |
Palavras-chave: Histoire Ifremer. |
| Ano: 1976 |
URL: http://archimer.ifremer.fr/doc/1976/publication-5007.pdf |
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| Auffret, Gérard-andré. |
| Les marges continentales peuvent-elles encore aujourd'hui être qualifiées de "ceinture d'ignorance", ainsi que DRAKE et BURK les qualifièrent en 1974 ? Certes, depuis cette date, les explorations pétrolières et les forages profonds ont commencé de combler ce vide de connaissances. Les premières cartes bathymétriques levées avec un faisceau à multiples rayons, et quelques explorations en submersibles nous ont permis de "voir" enfin les traits d'un paysage. |
| Tipo: Text |
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| Ano: 1983 |
URL: http://archimer.ifremer.fr/doc/00034/14524/11830.pdf |
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| Auffret, Gérard-andré; Pastouret, Léo; Chamley, Hervé; Lanoix, Franz. |
| The extent to which the prevailing current regime controls the nature of surface sediments in the Alboran Sea is suggested. Hydrographic data and surface sediments collected during the Polymède II cruise of the R.V. Jean Charcot in 1972 strongly suggest that the sediment distribution is controlled by the current system resulting from the difference in density between the Intermediate and Deep Mediterranean Water and Atlantic Surface Water. Clay, mainly montmorillonite, and planktonic Foraminifera are carried into the Mediterranean by east-flowing Atlantic Surface Water. As the suspended particles settle through the water column, they are redistributed by the westward-flowing deep currents and accumulate on the floor of the sea, where they constitute a... |
| Tipo: Text |
Palavras-chave: Histoire Ifremer. |
| Ano: 1974 |
URL: http://archimer.ifremer.fr/doc/1974/publication-5158.pdf |
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| Auffret, Gérard-andré. |
| Paleocene to Holocene sediments have been sampled from the northern margin of the Bay of Biscay (Meriadzek Terrace). Micropaleontological indicators suggest that this area has remained at upper abyssal depth (2000-2600 m) throughout this time ; moreover it seems to have been ouside the influence of massive terrigenous input through high density turbidity current. The comparaison of paleogene and quaternary sedimentary regimes points to a drastic difference between the sedimentation rate from these two episodes. This difference is related to the onset of global glaciation as soon as Middle Miocene with a subsequent increase of the sea level regressive trend which has been occuring since the uppermost Cretaceous. It appears to us that the sedimentary model... |
| Tipo: Text |
Palavras-chave: Histoire Ifremer. |
| Ano: 1979 |
URL: http://archimer.ifremer.fr/doc/1979/publication-5390.pdf |
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| Auffret, Gérard-andré; Pastouret, Léo. |
| We compare the post-lower Cretaceous sedimentary evolution on the Armorican and Blake Plateau continental margins. This comparison is based on lithological studies made on sediments from legs 44 and 48 of D.V. Glomar Challenger. These studies (mineralogy, textures, coarse fraction observation) and the consideration of the accumulation rates for each components, allow us to establish the similarity between the sedimentary regime on both margins. We notice particulary the simultaneous occurrence of a lowermost upper Cretaceous hiatus, reduced accumulation rates during Late Cretaceous and Paleocene ; the instauration of an active bottom current regime during Paleocene and its strengthening during Eocene and Oligocene ; a drastic incrcase of the accumulation... |
| Tipo: Text |
Palavras-chave: Histoire Ifremer. |
| Ano: 1978 |
URL: http://archimer.ifremer.fr/doc/1978/publication-5236.pdf |
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| Auffret, Gérard-andré; Berthois, L.; Douville, J.-l.. |
| The growing economic interest shown in the shallower regions of the continental shelf explains the present need to know moree about the contribution processes of the various sedimentary deposits. Mesurement of tidal currents and theoretical studies on the effect of waves in a number of sectors have provided an estimate ( table 1) of maximum probable sediment transport values (Bonneville. Sternberg). These are quite high, and range from 27.7 to 0.65 kg/m/s. It is clear that small differences in maximum current velocity give rise to large differences in the mass transport value. [NOT CONTROLLED OCR] |
| Tipo: Text |
Palavras-chave: Histoire Ifremer. |
| Ano: 1976 |
URL: http://archimer.ifremer.fr/doc/1976/publication-4989.pdf |
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| Pastouret, Léo; Auffret, Gérard-andré; Chambley, Hervé. |
| We characterized the microfacies of sediments encountered dunng Leg 44 on the basis of coarse fraction mineralogy ( sup 125 m), silt mineralogy (63 inf inf 20 m), clay mineralogy ( inf 2 m), silt and clay particle size distributions, and calcium carbonate contents. Secondly we attempted to tentatively correlate microfacies changes with major oceanographic events which have affected the sedimentary processes along the continental margin of North America.Because part of the stratigraphic column was not recovered (no Pliocene and Oligocene, and reduced Pleistocene and Barremian sections), and because of the fairly large sampling intervals our results are far from complete and exhaustive.Some important results, however, concerning the evolution of the... |
| Tipo: Text |
Palavras-chave: Histoire Ifremer. |
| Ano: 1978 |
URL: http://archimer.ifremer.fr/doc/1978/publication-5211.pdf |
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| Auffret, Gérard-andré; Pastouret, Léo; Cavanie, Alain; Lanoix, F.. |
| Three processes are called to explain the deposition of hemipelagic muds accounting for around 95 % of deposits in the Alboran Sea during the Holocene: general currents, distal part of a turbidite current, or a combination of these two causes a "gravity-assisted bottom current". We will discuss these hypotheses based on the results of the study of superficial sediment samples and the current measurements conducted during the Polymède II cruise (April-May 1972) by the R.S. "Jean Charcot", as well as on recent works about this region's hydrology (Lanoix, 1972). |
| Tipo: Text |
Palavras-chave: Histoire Ifremer. |
| Ano: 1972 |
URL: http://archimer.ifremer.fr/doc/1972/publication-5127.pdf |
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| Pastouret, Léo; Auffret, Gérard-andré. |
| The study of the rock and sediment dredgings carried out on the Armorican margin between 47 and 48° latitude North enables us to precise this latter's paleogeographical and tectonic evolution and to integrate it to the Bay of Biscay's. The microfacies analysis of the rock samples dating back from the Upper Jurassic to the Neogene era demonstrates: - on the one hand, the belonging of the northern edge of the Armorican margin to the Mesogean domain, at least up to the Mid-Cretaceous period; - on the other hand, the persistence of a carbonated platform regime which seems to operate from the Tithonian to the lower Tertiary phase, and on which reef could grow, especially in the Mid-Cretaceous period. Over the whole period, sedimentation compensated for... |
| Tipo: Text |
Palavras-chave: Histoire Ifremer. |
| Ano: 1976 |
URL: http://archimer.ifremer.fr/doc/1976/publication-5100.pdf |
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| Registros recuperados: 18 | |
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