Contribution of northern French data to the study of the role of thermokarst in the Pleistocene activity phases of elementary talwegs
International audience The network of elementary talwegs on slopes and interfluviums is considered to be a Pleistocene periglacial inheritance. However, the sedimentary deposits of the dry valleys are generally sparse and poorly informative. Eighteen indices of fluvial activity on slopes are reviewe...
Published in: | Géomorphologie : relief, processus, environnement |
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Other Authors: | , , |
Format: | Article in Journal/Newspaper |
Language: | French |
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HAL CCSD
2022
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Online Access: | https://inrap.hal.science/hal-04115744 https://doi.org/10.4000/geomorphologie.17174 |
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ftinstitutnrap:oai:HAL:hal-04115744v1 |
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record_format |
openpolar |
institution |
Open Polar |
collection |
INRAP: HAL (Institut national de recherches archéologiques préventives) |
op_collection_id |
ftinstitutnrap |
language |
French |
topic |
River bassin Escaut dry valley palaeo-talweg gully ice wedges network thermokarst thermo-erosion morphogenesis Pleistocene Weichselian Pléniglacial Bassin versant vallée sèche paléotalweg ravine réseaux de coins de glace thermo-érosion morphogenèse Pléistocène Pléniglaciaire weichselien [SHS.ARCHEO]Humanities and Social Sciences/Archaeology and Prehistory |
spellingShingle |
River bassin Escaut dry valley palaeo-talweg gully ice wedges network thermokarst thermo-erosion morphogenesis Pleistocene Weichselian Pléniglacial Bassin versant vallée sèche paléotalweg ravine réseaux de coins de glace thermo-érosion morphogenèse Pléistocène Pléniglaciaire weichselien [SHS.ARCHEO]Humanities and Social Sciences/Archaeology and Prehistory Deschodt, Laurent Contribution of northern French data to the study of the role of thermokarst in the Pleistocene activity phases of elementary talwegs |
topic_facet |
River bassin Escaut dry valley palaeo-talweg gully ice wedges network thermokarst thermo-erosion morphogenesis Pleistocene Weichselian Pléniglacial Bassin versant vallée sèche paléotalweg ravine réseaux de coins de glace thermo-érosion morphogenèse Pléistocène Pléniglaciaire weichselien [SHS.ARCHEO]Humanities and Social Sciences/Archaeology and Prehistory |
description |
International audience The network of elementary talwegs on slopes and interfluviums is considered to be a Pleistocene periglacial inheritance. However, the sedimentary deposits of the dry valleys are generally sparse and poorly informative. Eighteen indices of fluvial activity on slopes are reviewed in the French Scheldt basin and its margins. Most of them are infilled gullies. Several gully phases occurred during the Weichselian Pleniglacial (about 65 to 15 ka) in small basins (a few tens of thousands of m²), on interfluviums and upper slopes (six cases recorded) or in the plains (four cases). They are frequently associated with the remnants of ice wedges. Present-day examples of gully incision along ice wedges (thermo-erosion) in a context of permafrost degradation appear to be suitable analogues to explain the Pleistocene data. Stratigraphic arguments, some geochronological data and comparisons with neighbouring regions suggest that during the last cycle a rapid degradation of ice-rich permafrost occurred in the early Greenland Interstadial GI-15, -8, -4 and possibly in the early GI-2. The repetition of the phenomenon during the Pleistocene probably played a role in the genesis of the talwegs network on the interfluviums. The Pleistocene sediment budget of the collecting valleys is generally poorly developed, which implies an efficient downstream transit of the solid load during these episodes. Only three cases of thicker deposits are recorded in small valleys that were later completely or partially filled in by the covering loess of the late Weichselian Pleniglacial. A strong later activity is perceived on loessic lower slopes (2 cases). It is attributed to slope runoff during the Recent Dryas, but this time without evidence of permafrost. Le réseau de talwegs élémentaires sur versants et interfluves est réputé être un héritage périglaciaire pléistocène. Cependant les dépôts sédimentaires des vallons secs sont en général lacunaires et peu informatifs. Dix-huit indices d’activités fluviatiles sur versant ... |
author2 |
Laboratoire de géographie physique : Environnements Quaternaires et Actuels (LGP) Université Paris 1 Panthéon-Sorbonne (UP1)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS) Institut national de recherches archéologiques préventives (Inrap) |
format |
Article in Journal/Newspaper |
author |
Deschodt, Laurent |
author_facet |
Deschodt, Laurent |
author_sort |
Deschodt, Laurent |
title |
Contribution of northern French data to the study of the role of thermokarst in the Pleistocene activity phases of elementary talwegs |
title_short |
Contribution of northern French data to the study of the role of thermokarst in the Pleistocene activity phases of elementary talwegs |
title_full |
Contribution of northern French data to the study of the role of thermokarst in the Pleistocene activity phases of elementary talwegs |
title_fullStr |
Contribution of northern French data to the study of the role of thermokarst in the Pleistocene activity phases of elementary talwegs |
title_full_unstemmed |
Contribution of northern French data to the study of the role of thermokarst in the Pleistocene activity phases of elementary talwegs |
title_sort |
contribution of northern french data to the study of the role of thermokarst in the pleistocene activity phases of elementary talwegs |
publisher |
HAL CCSD |
publishDate |
2022 |
url |
https://inrap.hal.science/hal-04115744 https://doi.org/10.4000/geomorphologie.17174 |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Greenland Ice permafrost Thermokarst wedge* |
genre_facet |
Greenland Ice permafrost Thermokarst wedge* |
op_source |
ISSN: 1266-5304 EISSN: 1957-777X Géomorphologie : relief, processus, environnement https://inrap.hal.science/hal-04115744 Géomorphologie : relief, processus, environnement, 2022, Varia, 28 (3), pp.149-172. ⟨10.4000/geomorphologie.17174⟩ https://journals.openedition.org/geomorphologie/17174 |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.4000/geomorphologie.17174 hal-04115744 https://inrap.hal.science/hal-04115744 doi:10.4000/geomorphologie.17174 |
op_rights |
http://hal.archives-ouvertes.fr/licences/copyright/ |
op_doi |
https://doi.org/10.4000/geomorphologie.17174 |
container_title |
Géomorphologie : relief, processus, environnement |
container_volume |
28 |
container_issue |
3 |
container_start_page |
149 |
op_container_end_page |
172 |
_version_ |
1790601089489305600 |
spelling |
ftinstitutnrap:oai:HAL:hal-04115744v1 2024-02-11T10:04:29+01:00 Contribution of northern French data to the study of the role of thermokarst in the Pleistocene activity phases of elementary talwegs Contribution des données du nord de la France à l’étude du rôle du thermokarst dans les phases d’activités pléistocènes des talwegs élémentaires Deschodt, Laurent Laboratoire de géographie physique : Environnements Quaternaires et Actuels (LGP) Université Paris 1 Panthéon-Sorbonne (UP1)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS) Institut national de recherches archéologiques préventives (Inrap) 2022 https://inrap.hal.science/hal-04115744 https://doi.org/10.4000/geomorphologie.17174 fr fre HAL CCSD Groupe français de géomorphologie (GFG) / Société d'Études pour le Développement Économique et Social (Sedes) info:eu-repo/semantics/altIdentifier/doi/10.4000/geomorphologie.17174 hal-04115744 https://inrap.hal.science/hal-04115744 doi:10.4000/geomorphologie.17174 http://hal.archives-ouvertes.fr/licences/copyright/ ISSN: 1266-5304 EISSN: 1957-777X Géomorphologie : relief, processus, environnement https://inrap.hal.science/hal-04115744 Géomorphologie : relief, processus, environnement, 2022, Varia, 28 (3), pp.149-172. ⟨10.4000/geomorphologie.17174⟩ https://journals.openedition.org/geomorphologie/17174 River bassin Escaut dry valley palaeo-talweg gully ice wedges network thermokarst thermo-erosion morphogenesis Pleistocene Weichselian Pléniglacial Bassin versant vallée sèche paléotalweg ravine réseaux de coins de glace thermo-érosion morphogenèse Pléistocène Pléniglaciaire weichselien [SHS.ARCHEO]Humanities and Social Sciences/Archaeology and Prehistory info:eu-repo/semantics/article Journal articles 2022 ftinstitutnrap https://doi.org/10.4000/geomorphologie.17174 2024-01-24T17:24:04Z International audience The network of elementary talwegs on slopes and interfluviums is considered to be a Pleistocene periglacial inheritance. However, the sedimentary deposits of the dry valleys are generally sparse and poorly informative. Eighteen indices of fluvial activity on slopes are reviewed in the French Scheldt basin and its margins. Most of them are infilled gullies. Several gully phases occurred during the Weichselian Pleniglacial (about 65 to 15 ka) in small basins (a few tens of thousands of m²), on interfluviums and upper slopes (six cases recorded) or in the plains (four cases). They are frequently associated with the remnants of ice wedges. Present-day examples of gully incision along ice wedges (thermo-erosion) in a context of permafrost degradation appear to be suitable analogues to explain the Pleistocene data. Stratigraphic arguments, some geochronological data and comparisons with neighbouring regions suggest that during the last cycle a rapid degradation of ice-rich permafrost occurred in the early Greenland Interstadial GI-15, -8, -4 and possibly in the early GI-2. The repetition of the phenomenon during the Pleistocene probably played a role in the genesis of the talwegs network on the interfluviums. The Pleistocene sediment budget of the collecting valleys is generally poorly developed, which implies an efficient downstream transit of the solid load during these episodes. Only three cases of thicker deposits are recorded in small valleys that were later completely or partially filled in by the covering loess of the late Weichselian Pleniglacial. A strong later activity is perceived on loessic lower slopes (2 cases). It is attributed to slope runoff during the Recent Dryas, but this time without evidence of permafrost. Le réseau de talwegs élémentaires sur versants et interfluves est réputé être un héritage périglaciaire pléistocène. Cependant les dépôts sédimentaires des vallons secs sont en général lacunaires et peu informatifs. Dix-huit indices d’activités fluviatiles sur versant ... Article in Journal/Newspaper Greenland Ice permafrost Thermokarst wedge* INRAP: HAL (Institut national de recherches archéologiques préventives) Greenland Géomorphologie : relief, processus, environnement 28 3 149 172 |