Molards, a "new" landform to track permafrost degradation around the globe
International audience Few landforms exist that can be directly related to permafrost degradation, particularly in areas of discontinuous permafrost. Landform indicators of permafrost degradation such as retrogressive-thaw slumps, thermokarst lakes, and baydjarakhs are scarce, and generally occur on...
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ftunivangershal:oai:HAL:hal-02438761v1 2024-02-11T10:04:04+01:00 Molards, a "new" landform to track permafrost degradation around the globe Morino, Costanza Conway, Susan J. Deline, Philip Magnin, Florence School of Environment, Earth and Ecosystem Sciences Milton Keynes Faculty of Science, Technology, Engineering and Mathematics Milton Keynes The Open University Milton Keynes (OU)-The Open University Milton Keynes (OU) Laboratoire de Planétologie et Géodynamique UMR 6112 (LPG) Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST) Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS) Environnements, Dynamiques et Territoires de Montagne (EDYTEM) Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS) ANR-19-CE01-0010,Permolards,Les molards, marqueurs de l'évolution de la dégradation du pergélisol de montagne(2019) Paris, France 2020-02-03 https://hal.science/hal-02438761 en eng HAL CCSD hal-02438761 https://hal.science/hal-02438761 Colloque Q12 sur le Quaternaire https://hal.science/hal-02438761 Colloque Q12 sur le Quaternaire, Feb 2020, Paris, France [SDU.STU]Sciences of the Universe [physics]/Earth Sciences [SDE]Environmental Sciences info:eu-repo/semantics/conferenceObject Conference papers 2020 ftunivangershal 2024-01-24T17:25:28Z International audience Few landforms exist that can be directly related to permafrost degradation, particularly in areas of discontinuous permafrost. Landform indicators of permafrost degradation such as retrogressive-thaw slumps, thermokarst lakes, and baydjarakhs are scarce, and generally occur only in zones of continuous permafrost (e.g., Ashastina et al., 2017; Séjourné et al., 2015). Other periglacial landforms such as active rock glaciers, ice-cored moraines, or palsas need long-term monitoring of air/ground temperature or repeat geophysical surveys to detect the state of permafrost (e.g., Hilbich et al., 2009; Sæmundsson et al., 2012). This study explores the possibility to use the landform dubbed “molards” as a marker of permafrost degradation around the globe. Molards in permafrost terrains are cones of loose debris that result from thawing of blocks of ice-rich sediments mobilised by a landslide. Molards cannot form without ground ice, which cements the source material, allowing it to behave like solid during transport. Once the ground ice has thawed, its cementing action is lost, inducing collapse of the material into molards (Morino et al., 2019). In this study, we show that molards can be the only landform directly revealing permafrost degradation under different permafrost conditions, from continuous to discontinuous. We report on molards in landslides that we have identified and analysed from remote sensing around the globe, including Kamchatka, Iceland, Canada, Pakistan, and Greenland. We illustrate the different topographic and geomorphological settings where these molards are located, and we detail their morphometric and distribution characteristics, which give important insights into the permafrost conditions and landslide dynamics that brought to their emplacement. This study highlights the need for a better understanding of molard formation, evolution, morphology, longevity, and their environmental settings, and we emphasise that they can be used as a geomorphological tool to understand ... Conference Object glacier* Greenland Ice Iceland Kamchatka palsas permafrost Thermokarst Portail des publications scientifiques de l’Université d’Angers (HAL) Canada Greenland |
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Open Polar |
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Portail des publications scientifiques de l’Université d’Angers (HAL) |
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ftunivangershal |
language |
English |
topic |
[SDU.STU]Sciences of the Universe [physics]/Earth Sciences [SDE]Environmental Sciences |
spellingShingle |
[SDU.STU]Sciences of the Universe [physics]/Earth Sciences [SDE]Environmental Sciences Morino, Costanza Conway, Susan J. Deline, Philip Magnin, Florence Molards, a "new" landform to track permafrost degradation around the globe |
topic_facet |
[SDU.STU]Sciences of the Universe [physics]/Earth Sciences [SDE]Environmental Sciences |
description |
International audience Few landforms exist that can be directly related to permafrost degradation, particularly in areas of discontinuous permafrost. Landform indicators of permafrost degradation such as retrogressive-thaw slumps, thermokarst lakes, and baydjarakhs are scarce, and generally occur only in zones of continuous permafrost (e.g., Ashastina et al., 2017; Séjourné et al., 2015). Other periglacial landforms such as active rock glaciers, ice-cored moraines, or palsas need long-term monitoring of air/ground temperature or repeat geophysical surveys to detect the state of permafrost (e.g., Hilbich et al., 2009; Sæmundsson et al., 2012). This study explores the possibility to use the landform dubbed “molards” as a marker of permafrost degradation around the globe. Molards in permafrost terrains are cones of loose debris that result from thawing of blocks of ice-rich sediments mobilised by a landslide. Molards cannot form without ground ice, which cements the source material, allowing it to behave like solid during transport. Once the ground ice has thawed, its cementing action is lost, inducing collapse of the material into molards (Morino et al., 2019). In this study, we show that molards can be the only landform directly revealing permafrost degradation under different permafrost conditions, from continuous to discontinuous. We report on molards in landslides that we have identified and analysed from remote sensing around the globe, including Kamchatka, Iceland, Canada, Pakistan, and Greenland. We illustrate the different topographic and geomorphological settings where these molards are located, and we detail their morphometric and distribution characteristics, which give important insights into the permafrost conditions and landslide dynamics that brought to their emplacement. This study highlights the need for a better understanding of molard formation, evolution, morphology, longevity, and their environmental settings, and we emphasise that they can be used as a geomorphological tool to understand ... |
author2 |
School of Environment, Earth and Ecosystem Sciences Milton Keynes Faculty of Science, Technology, Engineering and Mathematics Milton Keynes The Open University Milton Keynes (OU)-The Open University Milton Keynes (OU) Laboratoire de Planétologie et Géodynamique UMR 6112 (LPG) Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST) Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS) Environnements, Dynamiques et Territoires de Montagne (EDYTEM) Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS) ANR-19-CE01-0010,Permolards,Les molards, marqueurs de l'évolution de la dégradation du pergélisol de montagne(2019) |
format |
Conference Object |
author |
Morino, Costanza Conway, Susan J. Deline, Philip Magnin, Florence |
author_facet |
Morino, Costanza Conway, Susan J. Deline, Philip Magnin, Florence |
author_sort |
Morino, Costanza |
title |
Molards, a "new" landform to track permafrost degradation around the globe |
title_short |
Molards, a "new" landform to track permafrost degradation around the globe |
title_full |
Molards, a "new" landform to track permafrost degradation around the globe |
title_fullStr |
Molards, a "new" landform to track permafrost degradation around the globe |
title_full_unstemmed |
Molards, a "new" landform to track permafrost degradation around the globe |
title_sort |
molards, a "new" landform to track permafrost degradation around the globe |
publisher |
HAL CCSD |
publishDate |
2020 |
url |
https://hal.science/hal-02438761 |
op_coverage |
Paris, France |
geographic |
Canada Greenland |
geographic_facet |
Canada Greenland |
genre |
glacier* Greenland Ice Iceland Kamchatka palsas permafrost Thermokarst |
genre_facet |
glacier* Greenland Ice Iceland Kamchatka palsas permafrost Thermokarst |
op_source |
Colloque Q12 sur le Quaternaire https://hal.science/hal-02438761 Colloque Q12 sur le Quaternaire, Feb 2020, Paris, France |
op_relation |
hal-02438761 https://hal.science/hal-02438761 |
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1790600534321790976 |