Permafrost saline water and Early to mid-Holocene permafrost aggradation in Svalbard
<p>Deglaciation in Svalbard was followed by seawater ingression and deposition of marine (deltaic) sediments in fjord valleys, while elastic rebound resulted in fast land uplift and the exposure of these sediments to the atmosphere, whereby the formation of epigenetic permafrost was initiated....
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2023-08-01
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| Series: | The Cryosphere |
| Online Access: | https://tc.copernicus.org/articles/17/3363/2023/tc-17-3363-2023.pdf |
| _version_ | 1797740098391900160 |
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| author | D. Rotem D. Rotem V. Lyakhovsky H. H. Christiansen Y. Harlavan Y. Weinstein |
| author_facet | D. Rotem D. Rotem V. Lyakhovsky H. H. Christiansen Y. Harlavan Y. Weinstein |
| author_sort | D. Rotem |
| collection | DOAJ |
| description | <p>Deglaciation in Svalbard was followed by seawater
ingression and deposition of marine (deltaic) sediments in fjord valleys,
while elastic rebound resulted in fast land uplift and the exposure of these sediments to the atmosphere, whereby the formation of epigenetic permafrost was initiated. This was then followed by the accumulation of aeolian sediments, with syngenetic permafrost formation. Permafrost was studied in the eastern Adventdalen valley, Svalbard, 3–4 km from the maximum up-valley reach of
post-deglaciation seawater ingression, and its ground ice was analysed for
its chemistry. While ground ice in the syngenetic part is basically fresh,
the epigenetic part has a frozen freshwater–saline water interface (FSI), with
chloride concentrations increasing from the top of the epigenetic part (at
5.5 m depth) to about 15 % that of seawater at 11 m depth. We applied a one-dimensional freezing model to examine the rate of top-down permafrost
formation, which could be accommodated by the observed frozen FSI. The model
examined permafrost development under different scenarios of mean average
air temperature, water freezing temperature and degree of pore-water
freezing. We found that even at the relatively high air temperatures of the
Early to mid-Holocene, permafrost could aggrade quite fast down to 20 to 37 m (the whole sediment fill of 25 m at this location) within 200 years. This, in turn, allowed freezing and preservation of the freshwater–saline water
interface despite the relatively fast rebound rate, which apparently
resulted in an increase in topographic gradients toward the sea. The
permafrost aggradation rate could also be enhanced due to non-complete pore-water freezing. We conclude that freezing must have started immediately
after the exposure of the marine sediment to atmospheric conditions.</p> |
| first_indexed | 2024-03-12T14:07:39Z |
| format | Article |
| id | doaj.art-539816a81a9d47ca94fe98012a9d2688 |
| institution | Directory Open Access Journal |
| issn | 1994-0416 1994-0424 |
| language | English |
| last_indexed | 2024-03-12T14:07:39Z |
| publishDate | 2023-08-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | The Cryosphere |
| spelling | doaj.art-539816a81a9d47ca94fe98012a9d26882023-08-21T13:11:13ZengCopernicus PublicationsThe Cryosphere1994-04161994-04242023-08-01173363338110.5194/tc-17-3363-2023Permafrost saline water and Early to mid-Holocene permafrost aggradation in SvalbardD. Rotem0D. Rotem1V. Lyakhovsky2H. H. Christiansen3Y. Harlavan4Y. Weinstein5Department of Geography and Environment, Bar-Ilan University, Ramat Gan 529002, IsraelArctic Geophysics Department, The University Centre in Svalbard (UNIS), Longyearbyen 9170, NorwayGeological Survey of Israel, 32 Yesha'yahu Leibowitz, Jerusalem 9692100, IsraelArctic Geophysics Department, The University Centre in Svalbard (UNIS), Longyearbyen 9170, NorwayGeological Survey of Israel, 32 Yesha'yahu Leibowitz, Jerusalem 9692100, IsraelDepartment of Geography and Environment, Bar-Ilan University, Ramat Gan 529002, Israel<p>Deglaciation in Svalbard was followed by seawater ingression and deposition of marine (deltaic) sediments in fjord valleys, while elastic rebound resulted in fast land uplift and the exposure of these sediments to the atmosphere, whereby the formation of epigenetic permafrost was initiated. This was then followed by the accumulation of aeolian sediments, with syngenetic permafrost formation. Permafrost was studied in the eastern Adventdalen valley, Svalbard, 3–4 km from the maximum up-valley reach of post-deglaciation seawater ingression, and its ground ice was analysed for its chemistry. While ground ice in the syngenetic part is basically fresh, the epigenetic part has a frozen freshwater–saline water interface (FSI), with chloride concentrations increasing from the top of the epigenetic part (at 5.5 m depth) to about 15 % that of seawater at 11 m depth. We applied a one-dimensional freezing model to examine the rate of top-down permafrost formation, which could be accommodated by the observed frozen FSI. The model examined permafrost development under different scenarios of mean average air temperature, water freezing temperature and degree of pore-water freezing. We found that even at the relatively high air temperatures of the Early to mid-Holocene, permafrost could aggrade quite fast down to 20 to 37 m (the whole sediment fill of 25 m at this location) within 200 years. This, in turn, allowed freezing and preservation of the freshwater–saline water interface despite the relatively fast rebound rate, which apparently resulted in an increase in topographic gradients toward the sea. The permafrost aggradation rate could also be enhanced due to non-complete pore-water freezing. We conclude that freezing must have started immediately after the exposure of the marine sediment to atmospheric conditions.</p>https://tc.copernicus.org/articles/17/3363/2023/tc-17-3363-2023.pdf |
| spellingShingle | D. Rotem D. Rotem V. Lyakhovsky H. H. Christiansen Y. Harlavan Y. Weinstein Permafrost saline water and Early to mid-Holocene permafrost aggradation in Svalbard The Cryosphere |
| title | Permafrost saline water and Early to mid-Holocene permafrost aggradation in Svalbard |
| title_full | Permafrost saline water and Early to mid-Holocene permafrost aggradation in Svalbard |
| title_fullStr | Permafrost saline water and Early to mid-Holocene permafrost aggradation in Svalbard |
| title_full_unstemmed | Permafrost saline water and Early to mid-Holocene permafrost aggradation in Svalbard |
| title_short | Permafrost saline water and Early to mid-Holocene permafrost aggradation in Svalbard |
| title_sort | permafrost saline water and early to mid holocene permafrost aggradation in svalbard |
| url | https://tc.copernicus.org/articles/17/3363/2023/tc-17-3363-2023.pdf |
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