Geothermal heat flux from measured temperature profiles in deep ice boreholes in Antarctica
The temperature at the Antarctic Ice Sheet bed and the temperature gradient in subglacial rocks have been directly measured only a few times, although extensive thermodynamic modeling has been used to estimate the geothermal heat flux (GHF) under the ice sheet. During the last 5 decades, deep ice-co...
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ftcopernicus:oai:publications.copernicus.org:tc83188 2023-05-15T13:31:39+02:00 Geothermal heat flux from measured temperature profiles in deep ice boreholes in Antarctica Talalay, Pavel Li, Yazhou Augustin, Laurent Clow, Gary D. Hong, Jialin Lefebvre, Eric Markov, Alexey Motoyama, Hideaki Ritz, Catherine 2020-11-14 application/pdf https://doi.org/10.5194/tc-14-4021-2020 https://tc.copernicus.org/articles/14/4021/2020/ eng eng doi:10.5194/tc-14-4021-2020 https://tc.copernicus.org/articles/14/4021/2020/ eISSN: 1994-0424 Text 2020 ftcopernicus https://doi.org/10.5194/tc-14-4021-2020 2020-11-16T17:22:14Z The temperature at the Antarctic Ice Sheet bed and the temperature gradient in subglacial rocks have been directly measured only a few times, although extensive thermodynamic modeling has been used to estimate the geothermal heat flux (GHF) under the ice sheet. During the last 5 decades, deep ice-core drilling projects at six sites – Byrd, WAIS Divide, Dome C, Kohnen, Dome F, and Vostok – have succeeded in reaching or nearly reaching the bed at inland locations in Antarctica. When temperature profiles in these boreholes and steady-state heat flow modeling are combined with estimates of vertical velocity, the heat flow at the ice-sheet base is translated to a geothermal heat flux of 57.9 ± 6.4 mW m −2 at Dome C, 78.9 ± 5.0 mW m −2 at Dome F, and 86.9 ± 16.6 mW m −2 at Kohnen, all higher than the predicted values at these sites. This warm base under the East Antarctic Ice Sheet (EAIS) could be caused by radiogenic heat effects or hydrothermal circulation not accounted for by the models. The GHF at the base of the ice sheet at Vostok has a negative value of − 3.6 ± 5.3 mW m −2 , indicating that water from Lake Vostok is freezing onto the ice-sheet base. Correlation analyses between modeled and measured depth–age scales at the EAIS sites indicate that all of them can be adequately approximated by a steady-state model. Horizontal velocities and their variation over ice-age cycles are much greater for the West Antarctic Ice Sheet than for the interior EAIS sites; a steady-state model cannot precisely describe the temperature distribution here. Even if the correlation factors for the best fitting age–depth curve are only moderate for the West Antarctic sites, the GHF values estimated here of 88.4 ± 7.6 mW m −2 at Byrd and 113.3 ± 16.9 mW m −2 at WAIS Divide can be used as references before more precise estimates are made on the subject. Text Antarc* Antarctic Antarctica ice core Ice Sheet Copernicus Publications: E-Journals Antarctic Byrd Dome F ENVELOPE(39.700,39.700,-77.317,-77.317) East Antarctic Ice Sheet Kohnen ENVELOPE(0.000,0.000,-75.000,-75.000) Lake Vostok ENVELOPE(106.000,106.000,-77.500,-77.500) The Antarctic West Antarctic Ice Sheet The Cryosphere 14 11 4021 4037 |
institution |
Open Polar |
collection |
Copernicus Publications: E-Journals |
op_collection_id |
ftcopernicus |
language |
English |
description |
The temperature at the Antarctic Ice Sheet bed and the temperature gradient in subglacial rocks have been directly measured only a few times, although extensive thermodynamic modeling has been used to estimate the geothermal heat flux (GHF) under the ice sheet. During the last 5 decades, deep ice-core drilling projects at six sites – Byrd, WAIS Divide, Dome C, Kohnen, Dome F, and Vostok – have succeeded in reaching or nearly reaching the bed at inland locations in Antarctica. When temperature profiles in these boreholes and steady-state heat flow modeling are combined with estimates of vertical velocity, the heat flow at the ice-sheet base is translated to a geothermal heat flux of 57.9 ± 6.4 mW m −2 at Dome C, 78.9 ± 5.0 mW m −2 at Dome F, and 86.9 ± 16.6 mW m −2 at Kohnen, all higher than the predicted values at these sites. This warm base under the East Antarctic Ice Sheet (EAIS) could be caused by radiogenic heat effects or hydrothermal circulation not accounted for by the models. The GHF at the base of the ice sheet at Vostok has a negative value of − 3.6 ± 5.3 mW m −2 , indicating that water from Lake Vostok is freezing onto the ice-sheet base. Correlation analyses between modeled and measured depth–age scales at the EAIS sites indicate that all of them can be adequately approximated by a steady-state model. Horizontal velocities and their variation over ice-age cycles are much greater for the West Antarctic Ice Sheet than for the interior EAIS sites; a steady-state model cannot precisely describe the temperature distribution here. Even if the correlation factors for the best fitting age–depth curve are only moderate for the West Antarctic sites, the GHF values estimated here of 88.4 ± 7.6 mW m −2 at Byrd and 113.3 ± 16.9 mW m −2 at WAIS Divide can be used as references before more precise estimates are made on the subject. |
format |
Text |
author |
Talalay, Pavel Li, Yazhou Augustin, Laurent Clow, Gary D. Hong, Jialin Lefebvre, Eric Markov, Alexey Motoyama, Hideaki Ritz, Catherine |
spellingShingle |
Talalay, Pavel Li, Yazhou Augustin, Laurent Clow, Gary D. Hong, Jialin Lefebvre, Eric Markov, Alexey Motoyama, Hideaki Ritz, Catherine Geothermal heat flux from measured temperature profiles in deep ice boreholes in Antarctica |
author_facet |
Talalay, Pavel Li, Yazhou Augustin, Laurent Clow, Gary D. Hong, Jialin Lefebvre, Eric Markov, Alexey Motoyama, Hideaki Ritz, Catherine |
author_sort |
Talalay, Pavel |
title |
Geothermal heat flux from measured temperature profiles in deep ice boreholes in Antarctica |
title_short |
Geothermal heat flux from measured temperature profiles in deep ice boreholes in Antarctica |
title_full |
Geothermal heat flux from measured temperature profiles in deep ice boreholes in Antarctica |
title_fullStr |
Geothermal heat flux from measured temperature profiles in deep ice boreholes in Antarctica |
title_full_unstemmed |
Geothermal heat flux from measured temperature profiles in deep ice boreholes in Antarctica |
title_sort |
geothermal heat flux from measured temperature profiles in deep ice boreholes in antarctica |
publishDate |
2020 |
url |
https://doi.org/10.5194/tc-14-4021-2020 https://tc.copernicus.org/articles/14/4021/2020/ |
long_lat |
ENVELOPE(39.700,39.700,-77.317,-77.317) ENVELOPE(0.000,0.000,-75.000,-75.000) ENVELOPE(106.000,106.000,-77.500,-77.500) |
geographic |
Antarctic Byrd Dome F East Antarctic Ice Sheet Kohnen Lake Vostok The Antarctic West Antarctic Ice Sheet |
geographic_facet |
Antarctic Byrd Dome F East Antarctic Ice Sheet Kohnen Lake Vostok The Antarctic West Antarctic Ice Sheet |
genre |
Antarc* Antarctic Antarctica ice core Ice Sheet |
genre_facet |
Antarc* Antarctic Antarctica ice core Ice Sheet |
op_source |
eISSN: 1994-0424 |
op_relation |
doi:10.5194/tc-14-4021-2020 https://tc.copernicus.org/articles/14/4021/2020/ |
op_doi |
https://doi.org/10.5194/tc-14-4021-2020 |
container_title |
The Cryosphere |
container_volume |
14 |
container_issue |
11 |
container_start_page |
4021 |
op_container_end_page |
4037 |
_version_ |
1766019827710820352 |