Alpine permafrost thawing during the Medieval Warm Period identified from cryogenic cave carbonates
Coarse crystalline cryogenic cave carbonates (CCCcoarse) dated to the last glacial period are common in central European caves and provide convincing evidence of palaeo-permafrost during this time. Little is known, however, about the exact nature of the environment in which CCCcoarse formed as no mo...
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ftusouthflorida:oai:digitalcommons.usf.edu:kip_articles-1241 2023-08-15T12:42:47+02:00 Alpine permafrost thawing during the Medieval Warm Period identified from cryogenic cave carbonates Luetscher, M. Borreguero, M. Moseley, G. E. 2022-01-18T08:00:00Z https://digitalcommons.usf.edu/kip_articles/242 https://doi.org/10.5194/tc-7-1073-2013 unknown Digital Commons @ University of South Florida https://digitalcommons.usf.edu/kip_articles/242 https://doi.org/10.5194/tc-7-1073-2013 KIP Articles text 2022 ftusouthflorida https://doi.org/10.5194/tc-7-1073-2013 2023-07-23T16:33:00Z Coarse crystalline cryogenic cave carbonates (CCCcoarse) dated to the last glacial period are common in central European caves and provide convincing evidence of palaeo-permafrost during this time. Little is known, however, about the exact nature of the environment in which CCCcoarse formed as no modern analogue setting is known. Here, we report the first findings of sub-recent, albeit inactive, CCCcoarse from a cave of the Western Alps which is located in the present-day permafrost zone. The globular shape and the presence of ubiquitous euhedral crystal terminations are comparable to previously reported aggregates from the last glacial period and strongly suggest that these aggregates formed subaqueously in pools lacking agitation. Furthermore, stable isotope values of mm-sized spheroids point to calcite precipitation in a closed system with respect to CO2, strongly supporting the hypothesis of a cryogenic origin associated with the freezing of water ponds. U-series analyses revealed three clusters of late Holocene calcite precipitation intervals between 2129 and 751 a b2k. These ages correlate with known periods of elevated summer temperatures, suggesting that warming and thawing of the frozen catchment above the cave allowed water infiltration into the karst system. The growth of CCCcoarse resulted from the re-freezing of this water in the still cold karst cavities. Text permafrost University of South Florida St. Petersburg: Digital USFSP The Cryosphere 7 4 1073 1081 |
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Open Polar |
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University of South Florida St. Petersburg: Digital USFSP |
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ftusouthflorida |
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description |
Coarse crystalline cryogenic cave carbonates (CCCcoarse) dated to the last glacial period are common in central European caves and provide convincing evidence of palaeo-permafrost during this time. Little is known, however, about the exact nature of the environment in which CCCcoarse formed as no modern analogue setting is known. Here, we report the first findings of sub-recent, albeit inactive, CCCcoarse from a cave of the Western Alps which is located in the present-day permafrost zone. The globular shape and the presence of ubiquitous euhedral crystal terminations are comparable to previously reported aggregates from the last glacial period and strongly suggest that these aggregates formed subaqueously in pools lacking agitation. Furthermore, stable isotope values of mm-sized spheroids point to calcite precipitation in a closed system with respect to CO2, strongly supporting the hypothesis of a cryogenic origin associated with the freezing of water ponds. U-series analyses revealed three clusters of late Holocene calcite precipitation intervals between 2129 and 751 a b2k. These ages correlate with known periods of elevated summer temperatures, suggesting that warming and thawing of the frozen catchment above the cave allowed water infiltration into the karst system. The growth of CCCcoarse resulted from the re-freezing of this water in the still cold karst cavities. |
format |
Text |
author |
Luetscher, M. Borreguero, M. Moseley, G. E. |
spellingShingle |
Luetscher, M. Borreguero, M. Moseley, G. E. Alpine permafrost thawing during the Medieval Warm Period identified from cryogenic cave carbonates |
author_facet |
Luetscher, M. Borreguero, M. Moseley, G. E. |
author_sort |
Luetscher, M. |
title |
Alpine permafrost thawing during the Medieval Warm Period identified from cryogenic cave carbonates |
title_short |
Alpine permafrost thawing during the Medieval Warm Period identified from cryogenic cave carbonates |
title_full |
Alpine permafrost thawing during the Medieval Warm Period identified from cryogenic cave carbonates |
title_fullStr |
Alpine permafrost thawing during the Medieval Warm Period identified from cryogenic cave carbonates |
title_full_unstemmed |
Alpine permafrost thawing during the Medieval Warm Period identified from cryogenic cave carbonates |
title_sort |
alpine permafrost thawing during the medieval warm period identified from cryogenic cave carbonates |
publisher |
Digital Commons @ University of South Florida |
publishDate |
2022 |
url |
https://digitalcommons.usf.edu/kip_articles/242 https://doi.org/10.5194/tc-7-1073-2013 |
genre |
permafrost |
genre_facet |
permafrost |
op_source |
KIP Articles |
op_relation |
https://digitalcommons.usf.edu/kip_articles/242 https://doi.org/10.5194/tc-7-1073-2013 |
op_doi |
https://doi.org/10.5194/tc-7-1073-2013 |
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The Cryosphere |
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7 |
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4 |
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1073 |
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1081 |
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1774297378657927168 |