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6 results on '"36Cl cosmic-ray exposure dating"'

1. Constraints on the timing of debris-covered and rock glaciers: An exploratory case study in the Holar area, northern Iceland

Author

Fernández Fernández, José María, Palacios Estremera, David, De Andrés De Pablo, Nuria, Schimmelpfennig, Irene, Tanarro García, Luis Miguel, Brynjólfsson, Skafti, López-Acevedo, Francisco J., Sæmundsson, Þorsteinn, A.S.T.E.R. Team, Fernández Fernández, José María, Palacios Estremera, David, De Andrés De Pablo, Nuria, Schimmelpfennig, Irene, Tanarro García, Luis Miguel, Brynjólfsson, Skafti, López-Acevedo, Francisco J., Sæmundsson, Þorsteinn, and A.S.T.E.R. Team

Abstract

Eighteen samples for 36Cl Cosmic-Ray Exposure (CRE) dating were taken from glacially polished bedrocks, moraine boulders, fossil/active rock glaciers and debris-covered glaciers in Fremri-Grjótárdalur and Hóladalur cirques in the Víðinesdalur, Hofsdalur and Héðinsdalur valleys, close to Hólar village, in the Tröllaskagi peninsula, northern Iceland. Boulder sampling was preceded by a study of the boulder stability with the twofold aim of: ensuring that the surfaces to be sampled were stable enough for the reliable application of CRE dating, and to better understand the relation between the glacier dynamics and exposition history. The results show that the glaciers which occupy the valleys in Tröllaskagi began their retreat around 16 ka. Later, the glaciers advanced again around 11 ka within the cirques, and small moraines were formed. Thereafter, these small glaciers retreated and evolved into rock glaciers as debris from paraglacial processes accumulated on the glacier surface. The fronts of these rock glaciers stabilized definitively shortly after their formation and became eventually fossil after the melting of their internal ice. New rock glaciers and debris-covered glaciers formed afterwards, which still have internal ice at present, although their current dynamics are mostly related to subsidence. The stabilization of these rock glaciers and debris-covered glaciers is dated to the period between 7 and 3 ka, although they may have been reactivated during cold neoglacial periods. This research demonstrates the potential interest in applying CRE dating methods to debris-covered glaciers and rock glaciers to determine their origin, evolution, and phase of cessation of internal movement until they finally lost their internal ice and became fossil., Ministerio de Economía y Competitividad, Nils Mobility Program, Grupo de investigación Geografía Física de alta Montaña y Regiones Polares (UCM), Depto. de Geografía, Fac. de Geografía e Historia, TRUE, pub

Published
2024

2. Glacier extent in sub-Antarctic Kerguelen archipelago from MIS 3 period: Evidence from 36Cl dating.

Author

Jomelli, Vincent, Schimmelpfennig, Irene, Favier, Vincent, Mokadem, Fatima, Landais, Amaelle, Rinterknecht, Vincent, Brunstein, Daniel, Verfaillie, Deborah, Legentil, Claude, Aumaitre, Georges, Bourlès, Didier L., and Keddadouche, Karim

Subjects
*ICE sheets, *LAST Glacial Maximum, *RADIOCARBON dating, *GLACIAL melting, *OCEAN temperature
Abstract

Documenting sub-Antarctic glacier variations during the local last glacial maximum is of major interest to better understand their sensitivity to atmospheric and oceanic temperature changes in conjunction with Antarctic ice sheet changes. However, data are sparse because evidence of earlier glacier extents is for most sub-Antarctic islands located offshore making their observation complex. Here, we present 22 cosmogenic 36 Cl surface exposure ages obtained from five sites at Kerguelen to document the glacial history. The 36 Cl ages from roche moutonnee surfaces, erratics and boulders collected on moraines span from 41.9 ± 4.4 ka to 14.3 ± 1.1 ka. Ice began to retreat on the eastern part of the main island before 41.4 ± 4.4 ka. Slow deglaciation occurred from ∼41 to ∼29 ka. There is no evidence of advances between 29 ka and the Antarctic Cold Reversal (ACR) period (∼14.5–12.9 ka) period. During the ACR, however, the Bontemps and possibly Belvedere moraines were formed by the advance of a Cook Ice Cap outlet glacier and a local glacier on the Presque Ile Jeanne d’Arc, respectively. This glacier evolution differs partly from that of glaciers in New Zealand and in Patagonia. These asynchronous glacier changes in the sub-Antarctic region are however in agreement with sea surface temperature changes recorded around Antarctica, which suggest differences in the climate evolution of the Indo-Pacific and Atlantic sectors of Antarctica. [ABSTRACT FROM AUTHOR]

Published
2018
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3. A multi-proxy approach to Late Holocene fluctuations of Tungnahryggsjökull glaciers in the Tröllaskagi peninsula (northern Iceland)

Author

Skafti Brynjólfsson, Þorsteinn Sæmundsson, José M. Fernández-Fernández, José J. Zamorano, Leopoldo G. Sancho, Irene Schimmelpfennig, Nuria Andrés, David Palacios, Starri Heiðmarsson, Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Collège de France (CdF)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Institut National de la Recherche Agronomique (INRA), Náttúrustofa Norðurlands vestra (NNv), Ríkisins, Sveitafélag Skagafjarðar, Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Collège de France (CdF (institution))-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA), Universidad Complutense de Madrid = Complutense University of Madrid [Madrid] (UCM), Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Universidad Nacional Autónoma de México = National Autonomous University of Mexico (UNAM), and University of Iceland [Reykjavik]

Subjects
Mediterranean climate, Environmental Engineering, 010504 meteorology & atmospheric sciences, Iceland, Lichenometric dating, 010501 environmental sciences, 01 natural sciences, Peninsula, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, Environmental Chemistry, Glacial period, [SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology, [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology, Late Holocene glacier evolution, 36Cl Cosmic-Ray Exposure dating, Waste Management and Disposal, Holocene, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, geography, geography.geographical_feature_category, biology, Rhizocarpon geographicum, Glacier, biology.organism_classification, Pollution, 13. Climate action, Moraine, [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology, Little Ice Age, Physical geography, Tröllaskagi, Geology, Chronology
Abstract

International audience; The Tröllaskagi Peninsula in northern Iceland hosts more than a hundred small glaciers that have left a rich terrestrial record of Holocene climatic fluctuations in their forelands. Traditionally, it has been assumed that most of the Tröllaskagi glaciers reached their Late Holocene maximum extent during the Little Ice Age (LIA). However, there is evidence of slightly more advanced pre-LIA positions. LIA moraines from Iceland have been primary dated mostly through lichenometric dating, but the limitations of this technique do not allow dating of glacial advances prior to the 18th or 19th centuries. The application of 36Cl Cosmic-Ray Exposure (CRE) dating to Tungnahryggsjökull moraine sequences in Vesturdalur and Austurdalur (central Tröllaskagi) has revealed a number of pre-LIA glacial advances at ~400 and ~700 CE, and a number of LIA advances in the 15th and 17th centuries, the earliest LIA advances dated so far in Tröllaskagi. This technique hence shows that the LIA chronology in Tröllaskagi agrees with that of other European areas such as the Alps or the Mediterranean mountains. The combined use of lichenometric dating, aerial photographs, satellite images and fieldwork shows that the regional colonization lag of the commonly used lichen species Rhizocarpon geographicum is longer than previously assumed. For exploratory purposes, an alternative lichen species (Porpidia soredizodes) has been tested for lichenometric dating, estimating a tentative growth rate of 0.737 mm yr−1.

Published
2019

4. Glacier extent in sub-Antarctic Kerguelen archipelago from MIS 3 period: Evidence from 36Cl dating

Author

Vincent Favier, Amaelle Landais, Vincent Jomelli, Fatima Mokadem, Claude Legentil, Deborah Verfaillie, Didier Bourlès, Daniel Brunstein, Irene Schimmelpfennig, Georges Aumaître, Karim Keddadouche, Vincent Rinterknecht, 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), Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Collège de France (CdF (institution))-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA), Institut des Géosciences de l’Environnement (IGE), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Glaces et Continents, Climats et Isotopes Stables (GLACCIOS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Lieux, Identités, eSpaces, Activités (LISA), Université Pascal Paoli (UPP)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut de Recherche pour le Développement (IRD)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Université Panthéon-Sorbonne (UP1), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Collège de France (CdF)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Institut National de la Recherche Agronomique (INRA), Unité de Recherche Great Ice, Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS), DEES, University of St Andrews [Scotland], Laboratoire de glaciologie et géophysique de l'environnement (LGGE), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )

Subjects
Archeology, 010504 meteorology & atmospheric sciences, MIS 2-4, Antarctic ice sheet, 010502 geochemistry & geophysics, 01 natural sciences, Kerguelen, Antarctic Cold Reversal, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, Deglaciation, 36Cl cosmic-ray exposure dating, 14. Life underwater, Glacial period, [SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology, [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology, Ecology, Evolution, Behavior and Systematics, 0105 earth and related environmental sciences, Global and Planetary Change, geography, geography.geographical_feature_category, Geology, Glacier, Last Glacial Maximum, Glacier fluctuations, 13. Climate action, Moraine, [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology, Archipelago, Physical geography
Abstract

International audience; Documenting sub-Antarctic glacier variations during the local last glacial maximum is of major interest to better understand their sensitivity to atmospheric and oceanic temperature changes in conjunction with Antarctic ice sheet changes. However, data are sparse because evidence of earlier glacier extents is for most sub-Antarctic islands located offshore making their observation complex. Here, we present 22 cosmogenic 36Cl surface exposure ages obtained from five sites at Kerguelen to document the glacial history. The 36Cl ages from roche moutonnee surfaces, erratics and boulders collected on moraines span from 41.9 ± 4.4 ka to 14.3 ± 1.1 ka. Ice began to retreat on the eastern part of the main island before 41.4 ± 4.4 ka. Slow deglaciation occurred from ∼41 to ∼29 ka. There is no evidence of advances between 29 ka and the Antarctic Cold Reversal (ACR) period (∼14.5–12.9 ka) period. During the ACR, however, the Bontemps and possibly Belvedere moraines were formed by the advance of a Cook Ice Cap outlet glacier and a local glacier on the Presque Ile Jeanne d’Arc, respectively. This glacier evolution differs partly from that of glaciers in New Zealand and in Patagonia. These asynchronous glacier changes in the sub-Antarctic region are however in agreement with sea surface temperature changes recorded around Antarctica, which suggest differences in the climate evolution of the Indo-Pacific and Atlantic sectors of Antarctica.

Published
2018

5. Sub-Antartic glacier extensions in the Kerguelen region (49° S, Indian Ocean) over the past 24 000 years constrained by 36Cl moraine dating

Author

Georges Aumaître, Irene Schimmelpfennig, Vincent Jomelli, Fatima Mokadem, Didier Bourlès, Didier Swingedouw, Karim Keddadouche, Vincent Favier, Claude Legentil, Emmanuel Chapron, Deborah Verfaillie, Vincent Rinterknecht, Elisabeth Michel, Alain Jaouen, Daniel Brunstein, 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), Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de la Terre d'Orléans - UMR7327 (ISTO), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Géographie de l'environnement (GEODE), Université Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), Biogéosystèmes Continentaux - UMR7327, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut des Géosciences de l’Environnement (IGE), Institut de Recherche pour le Développement (IRD)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Paléocéanographie (PALEOCEAN), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Environnements et Paléoenvironnements OCéaniques (EPOC), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), L'Institut polaire français Paul-Emile Victor (IPEV), Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.), CNRS-INSU, ANR-10-EQPX-0024,ASTER-CEREGE,PLATEFORME DE GEOCHIMIE ISOTOPIQUE ASTER/CEREGE(2010), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Université Panthéon-Sorbonne (UP1), Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Aix Marseille Université (AMU)-Collège de France (CdF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université Toulouse - Jean Jaurès (UT2J), Laboratoire de glaciologie et géophysique de l'environnement (LGGE), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), UMR 5805 Environnements et Paléoenvironnements Océaniques et Continentaux (EPOC), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Collège de France (CdF)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Institut National de la Recherche Agronomique (INRA), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS), ANR-10-EQPX-0024/10-EQPX-0024,ASTER-CEREGE,PLATEFORME DE GEOCHIMIE ISOTOPIQUE ASTER/CEREGE(2010), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Collège de France (CdF (institution))-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA), Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), Université Toulouse - Jean Jaurès (UT2J)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut de Recherche pour le Développement (IRD)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), and Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE)

Subjects
Archeology, 010504 meteorology & atmospheric sciences, 36 cl cosmic-ray exposure dating, Climate change, 010502 geochemistry & geophysics, 01 natural sciences, Kerguelen, Ice core, Deglaciation, 36Cl cosmic-ray exposure dating, 14. Life underwater, Glacial period, [SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, Ecology, Evolution, Behavior and Systematics, Holocene, 0105 earth and related environmental sciences, Global and Planetary Change, geography, geography.geographical_feature_category, Geology, Last Glacial Maximum, Glacier, Glacier fluctuations, [SHS.GEO]Humanities and Social Sciences/Geography, Oceanography, 13. Climate action, Moraine, [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology, [SDU]Sciences of the Universe [physics], late glacial
Abstract

International audience; Similar to many other regions in the world, glaciers in the southern sub-polar regions are currently retreating. In the Kerguelen Islands (49°S, 69°E), the mass balance of the Cook Ice Cap (CIC), the largest ice cap in the region, experimented dramatic shrinking between 1960 and 2013 with retreat rates among the highest in the world. This observation needs to be evaluated in a long-term context. However, data on the past glacier extents are sparse in the sub-Antartic regions. To investigate the deglaciation pattern since the Last Glacial Maximum (LGM) period, we present the first 13 cosmogenic 36Cl surface exposure ages from four sites in the Kerguelen Islands. The 36Cl ages from erratic and moraine boulders span from 24.4±2.7 ka to 0.3±0.1 ka. We combined these ages with extisting glacio-marine radiocarbon ages and bathymetric data to document the temporal and spatial changes of the island's glacial history. Ice began to retreat on the main island before 24.4±2.7 ka until around the time of the Antartic Cold Reversal (ACR) period (-14.5-12.9 ka), during which the Bontemps moraine was formed by the advance of a CIC outlet glacier. Deglacication continued during the Holocene probably until 3 ka with evidence of miror advances during the last millennium. This chronology is in pace with majeor changes in the ᵟ18O in a recent West Antartica ice core record, showing that Kerguelen Islands glaciers are particularly sensitive and relevant to document climate change in the southern polar regions.

Published
2017

6. Constraints on the timing of debris-covered and rock glaciers: An exploratory case study in the Hólar area, northern Iceland.

Author

Fernández-Fernández, José M., Palacios, David, Andrés, Nuria, Schimmelpfennig, Irene, Tanarro, Luis M., Brynjólfsson, Skafti, López-Acevedo, Francisco J., Sæmundsson, Þorsteinn, and Team, A.S.T.E.R.

Subjects
*ROCK glaciers, *PERIGLACIAL processes, *GEOCHRONOMETRY, *GLACIERS, *GLACIAL landforms, *GLACIOLOGY, *GLACIAL melting
Abstract

Eighteen samples for 36Cl Cosmic-Ray Exposure (CRE) dating were taken from glacially polished bedrocks, moraine boulders, fossil/active rock glaciers and debris-covered glaciers in Fremri-Grjótárdalur and Hóladalur cirques in the Víðinesdalur, Hofsdalur and Héðinsdalur valleys, close to Hólar village, in the Tröllaskagi peninsula, northern Iceland. Boulder sampling was preceded by a study of the boulder stability with the twofold aim of: ensuring that the surfaces to be sampled were stable enough for the reliable application of CRE dating, and to better understand the relation between the glacier dynamics and exposition history. The results show that the glaciers which occupy the valleys in Tröllaskagi began their retreat around 16 ka. Later, the glaciers advanced again around 11 ka within the cirques, and small moraines were formed. Thereafter, these small glaciers retreated and evolved into rock glaciers as debris from paraglacial processes accumulated on the glacier surface. The fronts of these rock glaciers stabilized definitively shortly after their formation and became eventually fossil after the melting of their internal ice. New rock glaciers and debris-covered glaciers formed afterwards, which still have internal ice at present, although their current dynamics are mostly related to subsidence. The stabilization of these rock glaciers and debris-covered glaciers is dated to the period between 7 and 3 ka, although they may have been reactivated during cold neoglacial periods. This research demonstrates the potential interest in applying CRE dating methods to debris-covered glaciers and rock glaciers to determine their origin, evolution and phase of cessation of internal movement until they finally lost their internal ice and became fossil. Unlabelled Image • A novel cosmogenic dating to debris-covered and rock glaciers. • Debris-covered and rock glaciers were formed shortly after deglaciation at 11 ka. • They could have lost the mobility during Holocene Thermal Maximum. • They remain with stagnant ice because they are above the level of permafrost. • Inherent interest in applying cosmogenic dating methods to these formations. [ABSTRACT FROM AUTHOR]

Published
2020
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