Honeycomb development on Alexander Island, glacial history of George VI Sound and palaeoclimatic implications (Two Step Cliffs/Mars Oasis, W Antarctica)
International audience Abstract Combining the analyses of three generations of glacial deposits and of a range of geomorphic features including widespread honeycombs and tafonis at Two Step Cliffs / Mars Oasis (71°52'S, 68°15'W) provides new insights into the geomorphological evolution of...
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ftclermontuniv:oai:HAL:hal-00267381v1 2023-05-15T13:15:21+02:00 Honeycomb development on Alexander Island, glacial history of George VI Sound and palaeoclimatic implications (Two Step Cliffs/Mars Oasis, W Antarctica) André, Marie-Françoise Hall, Kevin Laboratoire de Géographie Physique et Environnementale (GEOLAB) Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut Sciences de l'Homme et de la Société (IR SHS UNILIM) Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Université Clermont Auvergne 2017-2020 (UCA 2017-2020 )-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA) 2005 https://hal.science/hal-00267381 en eng HAL CCSD Elsevier hal-00267381 https://hal.science/hal-00267381 ISSN: 0169-555X Geomorphology https://hal.science/hal-00267381 Geomorphology, 2005, 65, pp.117-138 Géographie physique Milieux naturels info:eu-repo/semantics/article Journal articles 2005 ftclermontuniv 2023-03-29T01:27:29Z International audience Abstract Combining the analyses of three generations of glacial deposits and of a range of geomorphic features including widespread honeycombs and tafonis at Two Step Cliffs / Mars Oasis (71°52'S, 68°15'W) provides new insights into the geomorphological evolution of West Antarctica, with special respect to alveolar weathering. At Two Step Terrace, indicators of the inherited character of cavernous weathering were found, such as 97 % non flaking and varnished backwalls, and 80 % tafoni floors that are till-covered and/or sealed by lithobiontic coatings. Based on the NE predominant aspect of the alveolized boulder faces, tafoni initiation is attributed to coastal salt spray weathering by halite coming from the George VI Sound during the 6.5 ka BP open water period. The present-day activity of these inherited cavities is restricted to roof flaking attributed to a combination of processes involving thermal stresses. This 6.5 ka BP phase of coastal alveolization is the first step of a six-stage Holocene geomorphological scenario that includes alternatively phases of glacial advance or stationing, and phases of vegetal colonization and/or rock weathering and aeolian abrasion on the deglaciated outcrops. This geomorphic scenario is tentatively correlated with the available palaeoenvironmental record in the Antarctic Peninsula region, with two potential geomorphic indicators of the Holocene Optimum being identified: 1. clusters of centimetric honeycombs facing the sound (marine optimum at 6.5 ka BP); 2. salmon-pink lithobiontic coatings preserved inside cavities and at the boulder surface (terrestrial optimum at 4-3 ka BP). Keywords : Antarctic Peninsula - Ice shelf fluctuations - Alveolar weathering – Lithobiontic film –Geomorphic and vegetational response to Holocene climate fluctuations Article in Journal/Newspaper Alexander Island Antarc* Antarctic Antarctic Peninsula Antarctica Ice Shelf W. Antarctica West Antarctica HAL Clermont Auvergne (Université Blaise Pascal Clermont-Ferrand/Université d'Auvergne) Alexander Island ENVELOPE(-69.895,-69.895,-71.287,-71.287) Antarctic Antarctic Peninsula George VI Sound ENVELOPE(-68.000,-68.000,-71.000,-71.000) Mars Oasis ENVELOPE(-68.250,-68.250,-71.879,-71.879) The Antarctic Two Step Cliffs ENVELOPE(-68.267,-68.267,-71.880,-71.880) West Antarctica |
institution |
Open Polar |
collection |
HAL Clermont Auvergne (Université Blaise Pascal Clermont-Ferrand/Université d'Auvergne) |
op_collection_id |
ftclermontuniv |
language |
English |
topic |
Géographie physique Milieux naturels |
spellingShingle |
Géographie physique Milieux naturels André, Marie-Françoise Hall, Kevin Honeycomb development on Alexander Island, glacial history of George VI Sound and palaeoclimatic implications (Two Step Cliffs/Mars Oasis, W Antarctica) |
topic_facet |
Géographie physique Milieux naturels |
description |
International audience Abstract Combining the analyses of three generations of glacial deposits and of a range of geomorphic features including widespread honeycombs and tafonis at Two Step Cliffs / Mars Oasis (71°52'S, 68°15'W) provides new insights into the geomorphological evolution of West Antarctica, with special respect to alveolar weathering. At Two Step Terrace, indicators of the inherited character of cavernous weathering were found, such as 97 % non flaking and varnished backwalls, and 80 % tafoni floors that are till-covered and/or sealed by lithobiontic coatings. Based on the NE predominant aspect of the alveolized boulder faces, tafoni initiation is attributed to coastal salt spray weathering by halite coming from the George VI Sound during the 6.5 ka BP open water period. The present-day activity of these inherited cavities is restricted to roof flaking attributed to a combination of processes involving thermal stresses. This 6.5 ka BP phase of coastal alveolization is the first step of a six-stage Holocene geomorphological scenario that includes alternatively phases of glacial advance or stationing, and phases of vegetal colonization and/or rock weathering and aeolian abrasion on the deglaciated outcrops. This geomorphic scenario is tentatively correlated with the available palaeoenvironmental record in the Antarctic Peninsula region, with two potential geomorphic indicators of the Holocene Optimum being identified: 1. clusters of centimetric honeycombs facing the sound (marine optimum at 6.5 ka BP); 2. salmon-pink lithobiontic coatings preserved inside cavities and at the boulder surface (terrestrial optimum at 4-3 ka BP). Keywords : Antarctic Peninsula - Ice shelf fluctuations - Alveolar weathering – Lithobiontic film –Geomorphic and vegetational response to Holocene climate fluctuations |
author2 |
Laboratoire de Géographie Physique et Environnementale (GEOLAB) Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut Sciences de l'Homme et de la Société (IR SHS UNILIM) Université de Limoges (UNILIM)-Université de Limoges (UNILIM)-Université Clermont Auvergne 2017-2020 (UCA 2017-2020 )-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA) |
format |
Article in Journal/Newspaper |
author |
André, Marie-Françoise Hall, Kevin |
author_facet |
André, Marie-Françoise Hall, Kevin |
author_sort |
André, Marie-Françoise |
title |
Honeycomb development on Alexander Island, glacial history of George VI Sound and palaeoclimatic implications (Two Step Cliffs/Mars Oasis, W Antarctica) |
title_short |
Honeycomb development on Alexander Island, glacial history of George VI Sound and palaeoclimatic implications (Two Step Cliffs/Mars Oasis, W Antarctica) |
title_full |
Honeycomb development on Alexander Island, glacial history of George VI Sound and palaeoclimatic implications (Two Step Cliffs/Mars Oasis, W Antarctica) |
title_fullStr |
Honeycomb development on Alexander Island, glacial history of George VI Sound and palaeoclimatic implications (Two Step Cliffs/Mars Oasis, W Antarctica) |
title_full_unstemmed |
Honeycomb development on Alexander Island, glacial history of George VI Sound and palaeoclimatic implications (Two Step Cliffs/Mars Oasis, W Antarctica) |
title_sort |
honeycomb development on alexander island, glacial history of george vi sound and palaeoclimatic implications (two step cliffs/mars oasis, w antarctica) |
publisher |
HAL CCSD |
publishDate |
2005 |
url |
https://hal.science/hal-00267381 |
long_lat |
ENVELOPE(-69.895,-69.895,-71.287,-71.287) ENVELOPE(-68.000,-68.000,-71.000,-71.000) ENVELOPE(-68.250,-68.250,-71.879,-71.879) ENVELOPE(-68.267,-68.267,-71.880,-71.880) |
geographic |
Alexander Island Antarctic Antarctic Peninsula George VI Sound Mars Oasis The Antarctic Two Step Cliffs West Antarctica |
geographic_facet |
Alexander Island Antarctic Antarctic Peninsula George VI Sound Mars Oasis The Antarctic Two Step Cliffs West Antarctica |
genre |
Alexander Island Antarc* Antarctic Antarctic Peninsula Antarctica Ice Shelf W. Antarctica West Antarctica |
genre_facet |
Alexander Island Antarc* Antarctic Antarctic Peninsula Antarctica Ice Shelf W. Antarctica West Antarctica |
op_source |
ISSN: 0169-555X Geomorphology https://hal.science/hal-00267381 Geomorphology, 2005, 65, pp.117-138 |
op_relation |
hal-00267381 https://hal.science/hal-00267381 |
_version_ |
1766268160390987776 |