Un exemple de tectonique de plate-forme : les causses majeurs (sud du massif central, France)

Charpal, O. De; Tremolieres, P.; Jean, F.; Masse, P

doi:10.2516/ogst:1974029

Cited by 17 publications

(9 citation statements)

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“…Numerous studies show that deformation occurred on land in the whole continental domain of North Africa, Iberia, and Europe (de Charpal et al, 1974;Letouzey and Tremolieres, 1980;Bergerat, 1985). The stress field is characterized by a northsouth horizontal compression, in agreement with the relative north-south compressive motion of Africa with respect to Eu rope (Savostin et al, 1986), which resulted in a transcurrent tec tonic regime from northeastern Iberia to the Rhine graben and the Bohemian Massif.…”

Section: Cenozoic Compressive Phasesmentioning

confidence: 99%

Physiography and Structure of the Western Iberian Continental Margin off Galicia, from Sea Beam and Seismic Data

Sibuet¹,

Mazé²,

Amortila³

et al. 1987

Proceedings of the Ocean Drilling Program

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A new bathymetric map, based on Sea Beam data, was compiled for the continental margin south of Galicia Bank, in the area of Ocean Drilling Program (ODP) Leg 103 drilling. Using a new series of 12 single-channel seismic profiles oriented perpendicularly to the continental margin and multichannel seismic profiles previously acquired in the area, we constructed a detailed map of the surface of the tilted fault blocks and half grabens formed during the Early Cretaceous phases of rifting. Tilted fault blocks 13-18 km apart and oriented roughly north-south, are continuous over distances of as great as 60 km. We divided the upper and lower parts of the margin on the basis of magnetic data, distance be tween tilted fault blocks, nature of sediments involved in the rifting processes (pre-and syn-rift or only syn-rift sedi ments). This report also discusses the significance of the S reflector located below the tilted fault blocks.

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Section: Cenozoic Compressive Phasesmentioning

confidence: 99%

Physiography and Structure of the Western Iberian Continental Margin off Galicia, from Sea Beam and Seismic Data

Sibuet¹,

Mazé²,

Amortila³

et al. 1987

Proceedings of the Ocean Drilling Program

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“…Their occurrence has led to overestimates of their role on the formation of the continental margin. On land, numerous studies show that deformation occurred in the whole continental domain at the same period (De Charpal et al, 1974) in France, England, and Germany. Another compressional event occurred since Miocene time but is restricted geographically to the north, in the southeastern part of the Paris Basin.…”

Section: The Cenozoic (Eocene) Deformationsmentioning

confidence: 99%

Rifting and Subsidence of the Northern Continental Margin of the Bay of Biscay

Montadert¹,

Roberts²,

Charpal³

et al. 1979

Initial Reports of the Deep Sea Drilling Project

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In the northeast Atlantic, DSDP drilling results, combined with intensive geophysical surveys, permit a proposed model of the structural evolution of a starved, passive continental margin. Environment and tectonics of the rifting phase have been established. Active rifting took place in Early Cretaceous time in a pre-existing marine basin in contrast to many subaerial rift systems. The overall tectonic style is characterized by a series of tilted fault blocks bounded in many cases by listric faults. The rotation of the blocks (20-30°) along listric faults reduced the thickness of the upper continental crust from 6 to 8 km to 4 to 5 km. Close to the near horizontal base of the listric faults, a strong horizontal reflector corresponding to the 6.3 to 4.9 km/s refraction interface has been interpreted as the boundary between the upper brittle and the lower ductile continental crusts. The Moho discontinuity, 25 km deep in the vicinity of the shelf break, is 12 km deep in the lower part of the margin. In this area the ductile part of the crust (6.3 km/s) is only 3 km thick. Drill, dredge, and seismic reflection data allow reconstruction of the topography of the sea floor at the end of rifting in Aptian time. In the axis of the rift system, submarine troughs 2.5 km deep existed. The mechanism of riftingis discussed. The thinning of the continental crust cannot beexplained by the 10 to 15 per cent of extension estimated for the upper brittle part. It is suggested that the ductile part of the crust is thinned by creep in response to tension in the continental plate. Knowing the topography of the sea floor at the end of rifting and the present depth of the Aptian datum, the absolute amount of subsidence can be determined on a transect of the margin after the beginning of accretion (late Aptian time). This value decreases continuously from the oceanic/ continental crust boundary (4000 m) to the shelf break. For each point of the margin, the subsidence versus time curve is an exponential, the time constant of which increases with depth. The post-rifting subsidence is essentially an isostatic adjustment to cooling of the lithosphere in which the continental crust previously has been thinned during the rifting process.

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“…We have focused on the Grands Causses area, 150 km north-east of the north Pyrenean frontal trust (NPFT; Figure 1). The contractional deformation of this area is usually associated with the Eocene Pyrenean tectonic pulse, although a syntectonic sedimentary record associated with these structures is lacking [13][14][15][16]. In the first part of this paper, the structural context of the Grands Causses domain has been highlighted.…”

Section: Introductionmentioning

confidence: 99%

Tectonic Record of Deformation in Intraplate Domains: Case Study of Far-Field Deformation in the Grands Causses Area, France

et al. 2020

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Although tectonic plates are usually considered as rigid blocks, intraplate deformation such as lithospheric buckling or diffuse brittle deformation has been recognized for a long time. However, the origin of these deformations remains puzzling. Indeed, whereas the chronology of deformation at plate boundaries can be constrained by numerous methods (syntectonic sedimentary record, thermochronology, etc.), dating of brittle structures (faults, veins, and joints) in the far-field domains remains challenging, preventing a global interpretation of the system as a whole. In this contribution, we have combined a tectonic study with a synkinematical geochronological study of fault-related calcites of the Grands Causses intraplate domain, north of the Pyrenean orogeny. We show that these faults record a much longer history of deformation than previously thought. The Mesozoic extension, usually attributed to an early Jurassic Tethysian rifting event, probably lasted until the Barremian-Aptian epoch, in response to the Pyrenean basin’s opening. The so-called “Pyrenean deformation” of the Grands Causses domain, usually associated with the paroxysm of deformation in the belt during the late Eocene, began much earlier, around 100 Ma, and lasted for more than 60-70 Ma. This study demonstrates the high sensitivity of an intraplate domain (Grands Causses area) to record extensional or compressional deformations occurring at the edge of neighbouring plates.

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Un exemple de tectonique de plate-forme : les causses majeurs (sud du massif central, France)

Cited by 17 publications

References 0 publications

Physiography and Structure of the Western Iberian Continental Margin off Galicia, from Sea Beam and Seismic Data

Physiography and Structure of the Western Iberian Continental Margin off Galicia, from Sea Beam and Seismic Data

Rifting and Subsidence of the Northern Continental Margin of the Bay of Biscay

Tectonic Record of Deformation in Intraplate Domains: Case Study of Far-Field Deformation in the Grands Causses Area, France

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