The Experts below are selected from a list of 2067 Experts worldwide ranked by ideXlab platform
Bernard Hallégouet - One of the best experts on this subject based on the ideXlab platform.
-
Middle Pleistocene seismically induced clay Diapirism in an intraplate zone, western Brittany, France
Quaternary Research, 2018Co-Authors: Brigitte Van Vliet-lanoë, Christine Authemayou, Stéphane Molliex, Michael Hugh Field, Manfred Frechen, Pascal Le Roy, Julie Perrot, Valérie Andrieu-ponel, Gwendoline Gregoire, Bernard HallégouetAbstract:The Brittany region of France is located in a low seismicity intraplate zone. Most of the instrumented earthquakes are limited to a shallow crustal depth without surface rupture. A paleoseismological analysis was performed on deposits on the Crozon Peninsula and in the Elorn estuary. We highlight hydroplastic deformations induced by liquefaction leading to clay Diapirism, which were likely triggered by past earthquakes. This Diapirism seems to be frequent in continental nonconsolidated sediments and to develop on the inherited tectonic structures, when a shallow water table and confining layers exist. Timing of deformation is dated using paleoenvironmental data, and electron spin resonance and infrared-stimulated luminescence dating methods. Two seismic periods were identified in western Europe during early Marine Oxygen Isotope Stage (MIS) 10 (~380 ka) and early MIS 8 (~280-265 ka). The lack of similar deformations affecting the Holocene tidal deposits in the Bay of Brest suggests that the magnitude of the triggering paleoearthquakes is probably higher (M w ~ 6) than the recent events (M w 5.4). These unusual intraplate major paleoearthquakes need specific factors affecting the far-field crustal stress loading to be triggered, such as a brief acceleration of the Africa-Eurasia lithospheric plate convergence, glacio-isostatic stress perturbations associated with the onset of major glaciations in northern Europe, or other processes induced by orbital forcing.
Gregoire Messager - One of the best experts on this subject based on the ideXlab platform.
-
jurassic rifting to post rift subsidence analysis in the central high atlas and its relation to salt Diapirism
Basin Research, 2018Co-Authors: Mar Moragas, Jaume Verges, Eduard Saura, J D Martinmartin, Gregoire Messager, Oscar Merinotome, Isabel Suarezruiz, Philippe RazinAbstract:The subsidence evolution of the Tethyan Moroccan Atlas Basin, presently inverted as the Central High Atlas, is characterised by an Early Jurassic rifting episode, synchronous with salt Diapirism of the Triassic evaporite-bearing rocks. Two contrasting regions of the rift basin - with and without salt Diapirism - are examined in order to assess the effect of salt tectonics in the evolution of subsidence patterns and stratigraphy. The Djebel Bou Dahar platform to basin system, located in the southern margin of the Atlas Basin, shows a Lower Jurassic record of normal faulting and lacks any evidence of salt Diapirism. In contrast, the Tazoult ridge and adjacent Amezrai basin, located in the centre of the Atlas Basin, reveals spectacular Early Jurassic Diapirism. In addition, we analyse alternative Central High Atlas post-Middle Jurassic geohistories based on new thermal and burial models (GENEX® 4.0.3 software), constrained by new vitrinite reflectance data from the Amezrai basin. The comparison of the new subsidence curves from the studied areas with published subsidence curves from the Moroccan Atlas, the Saharan Atlas (Algeria) and Tunisian Atlas show that fast subsidence peaks were diachronous along the strike, being younger towards the east from Early – Middle Jurassic to Late Cretaceous. This analysis also evidences a close relationship between these high subsidence rate episodes and salt Diapirism. This article is protected by copyright. All rights reserved.
-
salt tectonics in the atlas mountains of morocco
Permo-Triassic Salt Provinces of Europe North Africa and the Atlantic Margins#R##N#Tectonics and Hydrocarbon Potential, 2017Co-Authors: Jaume Verges, Mar Moragas, Eduard Saura, J D Martinmartin, Emilio Casciello, Ph Razin, Carine Grelaud, Manon Malaval, R Joussiame, Gregoire MessagerAbstract:Abstract The principal objective of this paper is to summarize the large data set gathered in the last few years on the Early-Middle Jurassic diapiric evolution in the well-exposed Central High Atlas in Morocco. Field data on both structural geology and sedimentology of halokinetic sequences, significant remote sensing mapping using good quality satellite images, thermal modeling and subsidence analysis, balanced and restored cross sections, and analog modeling allowed us to construct an integrated tectono-sedimentary interpretation of a salt-related rift basin. Three characteristic regions are summarized here to show the tectonic and diapiric evolution of the study region: Tazoult, Azourki, and Imilchil. Salt ridges (Tazoult, Jbel Azourki, and Tassent salt walls) above blind basement faults developed a polygonal array bounding thick synclines (minibasins) with different orientations. The Imilchil minibasins show diachronous age of their infill, which is a typical characteristic of diapiric regions. The Tazoult and Jbel Azourki salt walls developed an allochthonous salt body starting during the Late Pliensbachian-Aalenian time. Although only Lower and Middle Jurassic halokinetic sedimentary sequences are preserved in most of the Central High Atlas, younger synclines (minibasins) along the northern boundary of the Atlas (Demnate region) show development of Late Jurassic and Early Cretaceous minibasins. At the larger scale, the diachronous evolution of the extension and Diapirism along the Atlas Basin suggests that Diapirism and salt withdrawal play an important role during the development of the High Atlas in Morocco, Saharan Atlas in Algeria, and Tunisian Atlas in a similar way as it is fabulously imaged across the onshore and offshore Atlantic Moroccan basins.
J D Martinmartin - One of the best experts on this subject based on the ideXlab platform.
-
jurassic rifting to post rift subsidence analysis in the central high atlas and its relation to salt Diapirism
Basin Research, 2018Co-Authors: Mar Moragas, Jaume Verges, Eduard Saura, J D Martinmartin, Gregoire Messager, Oscar Merinotome, Isabel Suarezruiz, Philippe RazinAbstract:The subsidence evolution of the Tethyan Moroccan Atlas Basin, presently inverted as the Central High Atlas, is characterised by an Early Jurassic rifting episode, synchronous with salt Diapirism of the Triassic evaporite-bearing rocks. Two contrasting regions of the rift basin - with and without salt Diapirism - are examined in order to assess the effect of salt tectonics in the evolution of subsidence patterns and stratigraphy. The Djebel Bou Dahar platform to basin system, located in the southern margin of the Atlas Basin, shows a Lower Jurassic record of normal faulting and lacks any evidence of salt Diapirism. In contrast, the Tazoult ridge and adjacent Amezrai basin, located in the centre of the Atlas Basin, reveals spectacular Early Jurassic Diapirism. In addition, we analyse alternative Central High Atlas post-Middle Jurassic geohistories based on new thermal and burial models (GENEX® 4.0.3 software), constrained by new vitrinite reflectance data from the Amezrai basin. The comparison of the new subsidence curves from the studied areas with published subsidence curves from the Moroccan Atlas, the Saharan Atlas (Algeria) and Tunisian Atlas show that fast subsidence peaks were diachronous along the strike, being younger towards the east from Early – Middle Jurassic to Late Cretaceous. This analysis also evidences a close relationship between these high subsidence rate episodes and salt Diapirism. This article is protected by copyright. All rights reserved.
-
salt tectonics in the atlas mountains of morocco
Permo-Triassic Salt Provinces of Europe North Africa and the Atlantic Margins#R##N#Tectonics and Hydrocarbon Potential, 2017Co-Authors: Jaume Verges, Mar Moragas, Eduard Saura, J D Martinmartin, Emilio Casciello, Ph Razin, Carine Grelaud, Manon Malaval, R Joussiame, Gregoire MessagerAbstract:Abstract The principal objective of this paper is to summarize the large data set gathered in the last few years on the Early-Middle Jurassic diapiric evolution in the well-exposed Central High Atlas in Morocco. Field data on both structural geology and sedimentology of halokinetic sequences, significant remote sensing mapping using good quality satellite images, thermal modeling and subsidence analysis, balanced and restored cross sections, and analog modeling allowed us to construct an integrated tectono-sedimentary interpretation of a salt-related rift basin. Three characteristic regions are summarized here to show the tectonic and diapiric evolution of the study region: Tazoult, Azourki, and Imilchil. Salt ridges (Tazoult, Jbel Azourki, and Tassent salt walls) above blind basement faults developed a polygonal array bounding thick synclines (minibasins) with different orientations. The Imilchil minibasins show diachronous age of their infill, which is a typical characteristic of diapiric regions. The Tazoult and Jbel Azourki salt walls developed an allochthonous salt body starting during the Late Pliensbachian-Aalenian time. Although only Lower and Middle Jurassic halokinetic sedimentary sequences are preserved in most of the Central High Atlas, younger synclines (minibasins) along the northern boundary of the Atlas (Demnate region) show development of Late Jurassic and Early Cretaceous minibasins. At the larger scale, the diachronous evolution of the extension and Diapirism along the Atlas Basin suggests that Diapirism and salt withdrawal play an important role during the development of the High Atlas in Morocco, Saharan Atlas in Algeria, and Tunisian Atlas in a similar way as it is fabulously imaged across the onshore and offshore Atlantic Moroccan basins.
Brigitte Van Vliet-lanoë - One of the best experts on this subject based on the ideXlab platform.
-
Middle Pleistocene seismically induced clay Diapirism in an intraplate zone, western Brittany, France
Quaternary Research, 2018Co-Authors: Brigitte Van Vliet-lanoë, Christine Authemayou, Stéphane Molliex, Michael Hugh Field, Manfred Frechen, Pascal Le Roy, Julie Perrot, Valérie Andrieu-ponel, Gwendoline Gregoire, Bernard HallégouetAbstract:The Brittany region of France is located in a low seismicity intraplate zone. Most of the instrumented earthquakes are limited to a shallow crustal depth without surface rupture. A paleoseismological analysis was performed on deposits on the Crozon Peninsula and in the Elorn estuary. We highlight hydroplastic deformations induced by liquefaction leading to clay Diapirism, which were likely triggered by past earthquakes. This Diapirism seems to be frequent in continental nonconsolidated sediments and to develop on the inherited tectonic structures, when a shallow water table and confining layers exist. Timing of deformation is dated using paleoenvironmental data, and electron spin resonance and infrared-stimulated luminescence dating methods. Two seismic periods were identified in western Europe during early Marine Oxygen Isotope Stage (MIS) 10 (~380 ka) and early MIS 8 (~280-265 ka). The lack of similar deformations affecting the Holocene tidal deposits in the Bay of Brest suggests that the magnitude of the triggering paleoearthquakes is probably higher (M w ~ 6) than the recent events (M w 5.4). These unusual intraplate major paleoearthquakes need specific factors affecting the far-field crustal stress loading to be triggered, such as a brief acceleration of the Africa-Eurasia lithospheric plate convergence, glacio-isostatic stress perturbations associated with the onset of major glaciations in northern Europe, or other processes induced by orbital forcing.
Philippe Razin - One of the best experts on this subject based on the ideXlab platform.
-
jurassic rifting to post rift subsidence analysis in the central high atlas and its relation to salt Diapirism
Basin Research, 2018Co-Authors: Mar Moragas, Jaume Verges, Eduard Saura, J D Martinmartin, Gregoire Messager, Oscar Merinotome, Isabel Suarezruiz, Philippe RazinAbstract:The subsidence evolution of the Tethyan Moroccan Atlas Basin, presently inverted as the Central High Atlas, is characterised by an Early Jurassic rifting episode, synchronous with salt Diapirism of the Triassic evaporite-bearing rocks. Two contrasting regions of the rift basin - with and without salt Diapirism - are examined in order to assess the effect of salt tectonics in the evolution of subsidence patterns and stratigraphy. The Djebel Bou Dahar platform to basin system, located in the southern margin of the Atlas Basin, shows a Lower Jurassic record of normal faulting and lacks any evidence of salt Diapirism. In contrast, the Tazoult ridge and adjacent Amezrai basin, located in the centre of the Atlas Basin, reveals spectacular Early Jurassic Diapirism. In addition, we analyse alternative Central High Atlas post-Middle Jurassic geohistories based on new thermal and burial models (GENEX® 4.0.3 software), constrained by new vitrinite reflectance data from the Amezrai basin. The comparison of the new subsidence curves from the studied areas with published subsidence curves from the Moroccan Atlas, the Saharan Atlas (Algeria) and Tunisian Atlas show that fast subsidence peaks were diachronous along the strike, being younger towards the east from Early – Middle Jurassic to Late Cretaceous. This analysis also evidences a close relationship between these high subsidence rate episodes and salt Diapirism. This article is protected by copyright. All rights reserved.