Héritage Permien dans les Alpes du Sud – Expression d'une dynamique tectonique et magmatique dans les séries pélitiques et gréseuses du Dôme du Barrot (France)
HAL (Le Centre pour la Communication Scientifique Directe), Nov 1, 2021
Continental-dominated successions are often poorly constrained stratigraphically due to a lack of... more Continental-dominated successions are often poorly constrained stratigraphically due to a lack of robust biostratigraphic markers. This study provides the first dataset of δ 13 Corg together with magnetostratigraphic and biostratigraphic data from a thick continental-dominated succession at Lairière (northern Pyrenees, France). This section encompasses the latest Cretaceous up to the Paleocene-Eocene Thermal Maximum interval and is characterized by fluvial deposits, occasionally intercalated with continental carbonates, lacustrine deltaic deposits and shallow marine sediments. This work identifies δ 13 Corg events and assigns them to global δ 13 C geochemical events defined in Pyrenean and Tethyan marine successions, in which the stage boundaries are well calibrated. As the isotopic measurements are performed on dispersed organic matter in sedimentary rocks with a low organic content, we propose that analyses of the signal should take into consideration the depositional environment because variations in the organic matter content might affect the signal. We establish a high-resolution chronostratigraphy in terrestrial Paleocene deposits in the NE Pyrenean zone, recognize a late Selandian interval and define the Paleocene-Eocene Thermal Maximum event. Supplementary material: Palaeomagnetic results, geochemistry details and palynological analysis are available at org.insu.bib.cnrs.
The Red Beds series in the Erta Ale segment, North Afar. Evidence for a 6 Ma-old post-rift basin prior to continental rupturing
Tectonophysics, 2018
Abstract The Erta Ale rift segment, North Afar, is regarded as the most mature rift part within t... more Abstract The Erta Ale rift segment, North Afar, is regarded as the most mature rift part within the entire Afar rift system. Very little is known about its deformation history because of limited exposures of geological records in its inner floor, except volcanics of the Erta Ale chain, and the poorly-known Red Beds series along the flanks of the depression. An integrated study, combining sedimentological, geochemical, 40Ar-39Ar radiometric and tectonic approaches, has been devoted to Red Beds series flanking the depression to the SW. Our new results allow to argue that (1) the >300 m-thick Red Beds exposed section comprises alluvial deposits that enclose (2) basaltic lavas and related sill intrusions that both yield ~6 Ma 40Ar-39Ar ages and display similar geochemical affinities, (3) the Red Beds series locally overlap unconformably basement bounding terrains, and (4) are involved in a limited number of low-displacement normal faults that recorded a modest amount of extension (
The morpho-tectonic evolution of a pre-structured domain during compressive reactivation documented by the Late Cretaceous to Paleocene alluvial fans of the Montagne Sainte Victoire (SE-France)
HAL (Le Centre pour la Communication Scientifique Directe), 2007
Global carbon isotopic events in a Campanian–Maastrichtian deltaic succession (Tremp-Graus Basin, Spain) and multiproxy stratigraphy for high sedimentation rate environments
Global carbon isotopic events in a Campanian–Maastrichtian deltaic succession (Tremp-Graus Basin, Spain) and multiproxy stratigraphy for high sedimentation rate environments
Soil Development on Modern Distributive Fluvial Systems: Preliminary Observations with Implications for Interpretation of Paleosols in the Rock Record
New Frontiers in Paleopedology and Terrestrial Paleoclimatology: Paleosols and Soil Surface Analog Systems, 2013
ABSTRACT Understanding of controls on the distribution of soils in modern sedimentary basins faci... more ABSTRACT Understanding of controls on the distribution of soils in modern sedimentary basins facilitates interpretation of paleosols in the rock record. Here, we present information on soil distribution from a number of modern distributive fluvial systems (DFSs) in sedimentary basins developed in different climatic and tectonic settings. DFSs form an important part of modern alluvial sedimentary basins, and an understanding of the controls on soil development in these settings should facilitate interpretation of the alluvial rock record. The studied areas include: the Pilcomayo and Bermejo DFSs in the Andean foreland of Argentina, the Tista DFS of the Himalayan foreland basin in northern India, and the Okavango DFS developed in an intracontinental rift basin in Botswana. Soils in each of the examples are relatively immature and weakly developed. Where present, downdip changes (over distances .100 km) from relatively well-drained, relatively dry soils in sandy proximal areas to more poorly drained, relatively wet soils in more distal, clay-rich areas can be recognized. In the Andean example, this change is considered to be related to a downdip increase in precipitation and decreasing depth to water table. In the Himalayan system, this is considered to be due to a combination of decreasing depth to water table and increased surface flooding due to direct, monsoon-driven precipitation on the DFS surface. An increase in poorly drained soil development occurs near the toe of the DFS in Botswana, despite high transmission losses across the system. A key implication from these modern systems is that a change from well-drained to poorly drained soils is controlled by hydrology. This change occurs along a single isochronous surface that may extend for hundreds of kilometers and could be preserved in the rock record. Rock record examples that describe a downdip change from well-drained to poorly drained soils have been documented previously and are attributed to tectonic, climatic, autocyclic, and hydromorphic controls. Our studies from modern DFSs would suggest that a hydromorphic control is likely to be the most important factor. Criteria derived from modern DFSs for distinguishing between changes in soil type that record climate change include the observation that paleosols developed in the proximal well-drained area are likely to be associated with a sandy parent material and sand-dominated channel facies. In contrast, in the distal DFSs, more poorly drained soils are likely to be developed on a silt-or clay-rich parent material interbedded with a mixture of sandy and muddy meandering channel-fill deposits, crevasse splays, and floodplain sands and muds. Paleosols that record climate change should show no discernible relationship between parent material and soil type. While similar relationships between soil type and parent material have been described previously, their distribution within the context of a DFS has not been widely documented.
Soil Development on Modern Distributive Fluvial Systems: Preliminary Observations with Implications for Interpretation of Paleosols in the Rock Record
New Frontiers in Paleopedology and Terrestrial Paleoclimatology: Paleosols and Soil Surface Analog Systems, 2013
ABSTRACT Understanding of controls on the distribution of soils in modern sedimentary basins faci... more ABSTRACT Understanding of controls on the distribution of soils in modern sedimentary basins facilitates interpretation of paleosols in the rock record. Here, we present information on soil distribution from a number of modern distributive fluvial systems (DFSs) in sedimentary basins developed in different climatic and tectonic settings. DFSs form an important part of modern alluvial sedimentary basins, and an understanding of the controls on soil development in these settings should facilitate interpretation of the alluvial rock record. The studied areas include: the Pilcomayo and Bermejo DFSs in the Andean foreland of Argentina, the Tista DFS of the Himalayan foreland basin in northern India, and the Okavango DFS developed in an intracontinental rift basin in Botswana. Soils in each of the examples are relatively immature and weakly developed. Where present, downdip changes (over distances .100 km) from relatively well-drained, relatively dry soils in sandy proximal areas to more poorly drained, relatively wet soils in more distal, clay-rich areas can be recognized. In the Andean example, this change is considered to be related to a downdip increase in precipitation and decreasing depth to water table. In the Himalayan system, this is considered to be due to a combination of decreasing depth to water table and increased surface flooding due to direct, monsoon-driven precipitation on the DFS surface. An increase in poorly drained soil development occurs near the toe of the DFS in Botswana, despite high transmission losses across the system. A key implication from these modern systems is that a change from well-drained to poorly drained soils is controlled by hydrology. This change occurs along a single isochronous surface that may extend for hundreds of kilometers and could be preserved in the rock record. Rock record examples that describe a downdip change from well-drained to poorly drained soils have been documented previously and are attributed to tectonic, climatic, autocyclic, and hydromorphic controls. Our studies from modern DFSs would suggest that a hydromorphic control is likely to be the most important factor. Criteria derived from modern DFSs for distinguishing between changes in soil type that record climate change include the observation that paleosols developed in the proximal well-drained area are likely to be associated with a sandy parent material and sand-dominated channel facies. In contrast, in the distal DFSs, more poorly drained soils are likely to be developed on a silt-or clay-rich parent material interbedded with a mixture of sandy and muddy meandering channel-fill deposits, crevasse splays, and floodplain sands and muds. Paleosols that record climate change should show no discernible relationship between parent material and soil type. While similar relationships between soil type and parent material have been described previously, their distribution within the context of a DFS has not been widely documented.
The Early Infill of the Triassic Fundy Basin: Architecture of the Wolfville Formation and Basin Evolution
The Fundy Basin forms one of a series of early Mesozoic rift basins developed along the north-wes... more The Fundy Basin forms one of a series of early Mesozoic rift basins developed along the north-western Atlantic margin. It forms the conjugate margin to Morocco in the Central Atlantic. Syn-rift continental sediments were deposited during early Late Triassic times in the Fundy Basin. The sedimentary succession comprises the lower fluvio-aeolian Wolfville Fm, the overlying ephemeral fluvial/playa Blomidon Fm capped by basaltic lava (Olsen et al., 1989; Wade et al., 1996). Three sub-basins are present in the Fundy Basin: the Fundy sub-basin, the Minas subbasin to the east and the Chignecto sub-basin to the north. The Late Anisian-Carnian Wolfville Fm displays a complex interplay of coarse and fine-grained fluvial sandstones, Aeolian dune deposits and alluvial fan sediments. This study focuses on the stratigraphy of, and correlation within the fluvial deposits. The palaeogeography of the Wolfville Fm is analysed by determining the size of the braided river system and by taking an allost...
The Early Infill of the Triassic Fundy Basin: Architecture of the Wolfville Formation and Basin Evolution
The Fundy Basin forms one of a series of early Mesozoic rift basins developed along the north-wes... more The Fundy Basin forms one of a series of early Mesozoic rift basins developed along the north-western Atlantic margin. It forms the conjugate margin to Morocco in the Central Atlantic. Syn-rift continental sediments were deposited during early Late Triassic times in the Fundy Basin. The sedimentary succession comprises the lower fluvio-aeolian Wolfville Fm, the overlying ephemeral fluvial/playa Blomidon Fm capped by basaltic lava (Olsen et al., 1989; Wade et al., 1996). Three sub-basins are present in the Fundy Basin: the Fundy sub-basin, the Minas subbasin to the east and the Chignecto sub-basin to the north. The Late Anisian-Carnian Wolfville Fm displays a complex interplay of coarse and fine-grained fluvial sandstones, Aeolian dune deposits and alluvial fan sediments. This study focuses on the stratigraphy of, and correlation within the fluvial deposits. The palaeogeography of the Wolfville Fm is analysed by determining the size of the braided river system and by taking an allost...
N20° Pamplona Fault is not the only one What geodynamical phase is responsible for the developm... more N20° Pamplona Fault is not the only one What geodynamical phase is responsible for the development of these N20° structures ? A single extensional tectonic phase between ca. 300 and 280 Ma. is responsible for : Granulites exhumation Plutons intrusions Permian Bidarray Basin and N20° structures
N20° Pamplona Fault is not the only one What geodynamical phase is responsible for the developm... more N20° Pamplona Fault is not the only one What geodynamical phase is responsible for the development of these N20° structures ? A single extensional tectonic phase between ca. 300 and 280 Ma. is responsible for : Granulites exhumation Plutons intrusions Permian Bidarray Basin and N20° structures
HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific r... more HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific r... more HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
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