Internal structure and conditions of permafrost mounds at Umiujaq in Nunavik, Canada, inferred from field investigation and electrical resistivity tomography
A systematic approach was used for the interpretation of the electrical resistivity tomography carried out on two permafrost mounds at Umiujaq in Nunavik, Canada, to assess their internal structure and conditions. Prior information under the form of a geocryologic model of the permafrost mounds was...
Published in: | Canadian Journal of Earth Sciences |
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Canadian Science Publishing
2008
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crcansciencepubl:10.1139/e08-004 2024-06-23T07:53:37+00:00 Internal structure and conditions of permafrost mounds at Umiujaq in Nunavik, Canada, inferred from field investigation and electrical resistivity tomography Fortier, Richard LeBlanc, Anne-Marie Allard, Michel Buteau, Sylvie Calmels, Fabrice Gilbert, R. 2008 http://dx.doi.org/10.1139/e08-004 http://www.nrcresearchpress.com/doi/full-xml/10.1139/E08-004 http://www.nrcresearchpress.com/doi/pdf/10.1139/E08-004 en eng Canadian Science Publishing http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining Canadian Journal of Earth Sciences volume 45, issue 3, page 367-387 ISSN 0008-4077 1480-3313 journal-article 2008 crcansciencepubl https://doi.org/10.1139/e08-004 2024-06-13T04:10:48Z A systematic approach was used for the interpretation of the electrical resistivity tomography carried out on two permafrost mounds at Umiujaq in Nunavik, Canada, to assess their internal structure and conditions. Prior information under the form of a geocryologic model of the permafrost mounds was integrated in the inversion of the pseudo-section of apparent electrical resistivity. The geocryologic model was developed from the synthesis of previous field investigations, including shallow and deep sampling, temperature and electrical resistivity logging, and cone penetration tests performed in the permafrost mounds. Values of electrical resistivity were ascribed to the different layers making of the geocryologic model to define a synthetic resistivity model of the permafrost mounds used as a reference model to constrain the inversion. The constrained resistivity model clearly show the presence of ice-rich cores in the permafrost mounds underscored by high resistivity values in excess of 30 000 Ωm, while the unfrozen zones surrounding the permafrost mounds are characterized by resistivity values lower than 1000 Ωm. The spatial distribution of unfrozen water and ice contents in the permafrost mounds were also assessed according to empirical relationships between the electrical resistivity and water contents. The ice content is highly variable and can be as high as 80% in the ice-rich cores, while the unfrozen water content varies between 2% and 5%. The integration of prior information in the inversion process leads to a more realistic constrained resistivity model showing sharp resistivity contrasts expected at the boundaries such as the permafrost table and base. Article in Journal/Newspaper Ice permafrost Umiujaq Nunavik Canadian Science Publishing Nunavik Canada Umiujaq ENVELOPE(-76.549,-76.549,56.553,56.553) Canadian Journal of Earth Sciences 45 3 367 387 |
institution |
Open Polar |
collection |
Canadian Science Publishing |
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crcansciencepubl |
language |
English |
description |
A systematic approach was used for the interpretation of the electrical resistivity tomography carried out on two permafrost mounds at Umiujaq in Nunavik, Canada, to assess their internal structure and conditions. Prior information under the form of a geocryologic model of the permafrost mounds was integrated in the inversion of the pseudo-section of apparent electrical resistivity. The geocryologic model was developed from the synthesis of previous field investigations, including shallow and deep sampling, temperature and electrical resistivity logging, and cone penetration tests performed in the permafrost mounds. Values of electrical resistivity were ascribed to the different layers making of the geocryologic model to define a synthetic resistivity model of the permafrost mounds used as a reference model to constrain the inversion. The constrained resistivity model clearly show the presence of ice-rich cores in the permafrost mounds underscored by high resistivity values in excess of 30 000 Ωm, while the unfrozen zones surrounding the permafrost mounds are characterized by resistivity values lower than 1000 Ωm. The spatial distribution of unfrozen water and ice contents in the permafrost mounds were also assessed according to empirical relationships between the electrical resistivity and water contents. The ice content is highly variable and can be as high as 80% in the ice-rich cores, while the unfrozen water content varies between 2% and 5%. The integration of prior information in the inversion process leads to a more realistic constrained resistivity model showing sharp resistivity contrasts expected at the boundaries such as the permafrost table and base. |
author2 |
Gilbert, R. |
format |
Article in Journal/Newspaper |
author |
Fortier, Richard LeBlanc, Anne-Marie Allard, Michel Buteau, Sylvie Calmels, Fabrice |
spellingShingle |
Fortier, Richard LeBlanc, Anne-Marie Allard, Michel Buteau, Sylvie Calmels, Fabrice Internal structure and conditions of permafrost mounds at Umiujaq in Nunavik, Canada, inferred from field investigation and electrical resistivity tomography |
author_facet |
Fortier, Richard LeBlanc, Anne-Marie Allard, Michel Buteau, Sylvie Calmels, Fabrice |
author_sort |
Fortier, Richard |
title |
Internal structure and conditions of permafrost mounds at Umiujaq in Nunavik, Canada, inferred from field investigation and electrical resistivity tomography |
title_short |
Internal structure and conditions of permafrost mounds at Umiujaq in Nunavik, Canada, inferred from field investigation and electrical resistivity tomography |
title_full |
Internal structure and conditions of permafrost mounds at Umiujaq in Nunavik, Canada, inferred from field investigation and electrical resistivity tomography |
title_fullStr |
Internal structure and conditions of permafrost mounds at Umiujaq in Nunavik, Canada, inferred from field investigation and electrical resistivity tomography |
title_full_unstemmed |
Internal structure and conditions of permafrost mounds at Umiujaq in Nunavik, Canada, inferred from field investigation and electrical resistivity tomography |
title_sort |
internal structure and conditions of permafrost mounds at umiujaq in nunavik, canada, inferred from field investigation and electrical resistivity tomography |
publisher |
Canadian Science Publishing |
publishDate |
2008 |
url |
http://dx.doi.org/10.1139/e08-004 http://www.nrcresearchpress.com/doi/full-xml/10.1139/E08-004 http://www.nrcresearchpress.com/doi/pdf/10.1139/E08-004 |
long_lat |
ENVELOPE(-76.549,-76.549,56.553,56.553) |
geographic |
Nunavik Canada Umiujaq |
geographic_facet |
Nunavik Canada Umiujaq |
genre |
Ice permafrost Umiujaq Nunavik |
genre_facet |
Ice permafrost Umiujaq Nunavik |
op_source |
Canadian Journal of Earth Sciences volume 45, issue 3, page 367-387 ISSN 0008-4077 1480-3313 |
op_rights |
http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining |
op_doi |
https://doi.org/10.1139/e08-004 |
container_title |
Canadian Journal of Earth Sciences |
container_volume |
45 |
container_issue |
3 |
container_start_page |
367 |
op_container_end_page |
387 |
_version_ |
1802645358872887296 |