Revisiting Austfonna, Svalbard, with potential field methods – a new characterization of the bed topography and its physical properties
With hundreds of metres of ice, the bedrock underlying Austfonna, the largest icecap on Svalbard, is hard to characterize in terms of topography and physical properties. Ground-penetrating radar (GPR) measurements supply ice thickness estimation, but the data quality is temperature dependent, leadin...
Published in: | The Cryosphere |
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Format: | Article in Journal/Newspaper |
Language: | English |
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Copernicus Publications
2020
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ftnonlinearchiv:oai:noa.gwlb.de:cop_mods_00050377 2023-05-15T15:33:55+02:00 Revisiting Austfonna, Svalbard, with potential field methods – a new characterization of the bed topography and its physical properties Dumais, Marie-Andrée Brönner, Marco 2020-01 electronic https://doi.org/10.5194/tc-14-183-2020 https://noa.gwlb.de/receive/cop_mods_00050377 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00049990/tc-14-183-2020.pdf https://tc.copernicus.org/articles/14/183/2020/tc-14-183-2020.pdf eng eng Copernicus Publications The Cryosphere -- ˜Theœ Cryosphere -- http://www.bibliothek.uni-regensburg.de/ezeit/?2393169 -- http://www.the-cryosphere.net/ -- 1994-0424 https://doi.org/10.5194/tc-14-183-2020 https://noa.gwlb.de/receive/cop_mods_00050377 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00049990/tc-14-183-2020.pdf https://tc.copernicus.org/articles/14/183/2020/tc-14-183-2020.pdf https://creativecommons.org/licenses/by/4.0/ uneingeschränkt info:eu-repo/semantics/openAccess CC-BY article Verlagsveröffentlichung article Text doc-type:article 2020 ftnonlinearchiv https://doi.org/10.5194/tc-14-183-2020 2022-02-08T22:36:54Z With hundreds of metres of ice, the bedrock underlying Austfonna, the largest icecap on Svalbard, is hard to characterize in terms of topography and physical properties. Ground-penetrating radar (GPR) measurements supply ice thickness estimation, but the data quality is temperature dependent, leading to uncertainties. To remedy this, we include airborne gravity measurements. With a significant density contrast between ice and bedrock, subglacial bed topography is effectively derived from gravity modelling. While the ice thickness model relies primarily on the gravity data, integrating airborne magnetic data provides an extra insight into the basement distribution. This contributes to refining the range of density expected under the ice and improving the subice model. For this study, a prominent magmatic north–south-oriented intrusion and the presence of carbonates are assessed. The results reveal the complexity of the subsurface lithology, characterized by different basement affinities. With the geophysical parameters of the bedrock determined, a new bed topography is extracted and adjusted for the potential field interpretation, i.e. magnetic- and gravity-data analysis and modelling. When the results are compared to bed elevation maps previously produced by radio-echo sounding (RES) and GPR data, the discrepancies are pronounced where the RES and GPR data are scarce. Hence, areas with limited coverage are addressed with the potential field interpretation, increasing the accuracy of the overall bed topography. In addition, the methodology improves understanding of the geology; assigns physical properties to the basements; and reveals the presence of softer bed, carbonates and magmatic intrusions under Austfonna, which influence the basal-sliding rates and surges. Article in Journal/Newspaper Austfonna Svalbard The Cryosphere Niedersächsisches Online-Archiv NOA Austfonna ENVELOPE(24.559,24.559,79.835,79.835) Svalbard The Cryosphere 14 1 183 197 |
institution |
Open Polar |
collection |
Niedersächsisches Online-Archiv NOA |
op_collection_id |
ftnonlinearchiv |
language |
English |
topic |
article Verlagsveröffentlichung |
spellingShingle |
article Verlagsveröffentlichung Dumais, Marie-Andrée Brönner, Marco Revisiting Austfonna, Svalbard, with potential field methods – a new characterization of the bed topography and its physical properties |
topic_facet |
article Verlagsveröffentlichung |
description |
With hundreds of metres of ice, the bedrock underlying Austfonna, the largest icecap on Svalbard, is hard to characterize in terms of topography and physical properties. Ground-penetrating radar (GPR) measurements supply ice thickness estimation, but the data quality is temperature dependent, leading to uncertainties. To remedy this, we include airborne gravity measurements. With a significant density contrast between ice and bedrock, subglacial bed topography is effectively derived from gravity modelling. While the ice thickness model relies primarily on the gravity data, integrating airborne magnetic data provides an extra insight into the basement distribution. This contributes to refining the range of density expected under the ice and improving the subice model. For this study, a prominent magmatic north–south-oriented intrusion and the presence of carbonates are assessed. The results reveal the complexity of the subsurface lithology, characterized by different basement affinities. With the geophysical parameters of the bedrock determined, a new bed topography is extracted and adjusted for the potential field interpretation, i.e. magnetic- and gravity-data analysis and modelling. When the results are compared to bed elevation maps previously produced by radio-echo sounding (RES) and GPR data, the discrepancies are pronounced where the RES and GPR data are scarce. Hence, areas with limited coverage are addressed with the potential field interpretation, increasing the accuracy of the overall bed topography. In addition, the methodology improves understanding of the geology; assigns physical properties to the basements; and reveals the presence of softer bed, carbonates and magmatic intrusions under Austfonna, which influence the basal-sliding rates and surges. |
format |
Article in Journal/Newspaper |
author |
Dumais, Marie-Andrée Brönner, Marco |
author_facet |
Dumais, Marie-Andrée Brönner, Marco |
author_sort |
Dumais, Marie-Andrée |
title |
Revisiting Austfonna, Svalbard, with potential field methods – a new characterization of the bed topography and its physical properties |
title_short |
Revisiting Austfonna, Svalbard, with potential field methods – a new characterization of the bed topography and its physical properties |
title_full |
Revisiting Austfonna, Svalbard, with potential field methods – a new characterization of the bed topography and its physical properties |
title_fullStr |
Revisiting Austfonna, Svalbard, with potential field methods – a new characterization of the bed topography and its physical properties |
title_full_unstemmed |
Revisiting Austfonna, Svalbard, with potential field methods – a new characterization of the bed topography and its physical properties |
title_sort |
revisiting austfonna, svalbard, with potential field methods – a new characterization of the bed topography and its physical properties |
publisher |
Copernicus Publications |
publishDate |
2020 |
url |
https://doi.org/10.5194/tc-14-183-2020 https://noa.gwlb.de/receive/cop_mods_00050377 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00049990/tc-14-183-2020.pdf https://tc.copernicus.org/articles/14/183/2020/tc-14-183-2020.pdf |
long_lat |
ENVELOPE(24.559,24.559,79.835,79.835) |
geographic |
Austfonna Svalbard |
geographic_facet |
Austfonna Svalbard |
genre |
Austfonna Svalbard The Cryosphere |
genre_facet |
Austfonna Svalbard The Cryosphere |
op_relation |
The Cryosphere -- ˜Theœ Cryosphere -- http://www.bibliothek.uni-regensburg.de/ezeit/?2393169 -- http://www.the-cryosphere.net/ -- 1994-0424 https://doi.org/10.5194/tc-14-183-2020 https://noa.gwlb.de/receive/cop_mods_00050377 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00049990/tc-14-183-2020.pdf https://tc.copernicus.org/articles/14/183/2020/tc-14-183-2020.pdf |
op_rights |
https://creativecommons.org/licenses/by/4.0/ uneingeschränkt info:eu-repo/semantics/openAccess |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.5194/tc-14-183-2020 |
container_title |
The Cryosphere |
container_volume |
14 |
container_issue |
1 |
container_start_page |
183 |
op_container_end_page |
197 |
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1766364504774410240 |