Development of low–centred ice–wedge polygons in the northernmost Ungava Peninsual, Queébec, Canada
Morphological and vegetation mapping and stratigraphic studies were carried out on a 60 by 250 m low–centered polygon field on a flood–plain of the Riviére Deception in the continuous permafrost zone of northernmost Ungava. Analyses of grain size, water and ice content, deformation structures, and m...
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crwiley:10.1111/j.1502-3885.1991.tb00155.x 2024-06-23T07:53:39+00:00 Development of low–centred ice–wedge polygons in the northernmost Ungava Peninsual, Queébec, Canada SEPPALA, MATTI GRAY, JAMES RICARD, JEAN 1991 http://dx.doi.org/10.1111/j.1502-3885.1991.tb00155.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1502-3885.1991.tb00155.x https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1502-3885.1991.tb00155.x en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor Boreas volume 20, issue 3, page 259-285 ISSN 0300-9483 1502-3885 journal-article 1991 crwiley https://doi.org/10.1111/j.1502-3885.1991.tb00155.x 2024-06-11T04:46:11Z Morphological and vegetation mapping and stratigraphic studies were carried out on a 60 by 250 m low–centered polygon field on a flood–plain of the Riviére Deception in the continuous permafrost zone of northernmost Ungava. Analyses of grain size, water and ice content, deformation structures, and macrorests were carried out on drill–core samples, up to a maximum depth of 3.19 m, and radiocarbon dates were obtained from several peat horizons. Five different vegetational habits were identified: uplifted banks, ice–wedge fissures, hummocky centres, wet polygon centres, and water ponds. The stratigraphic analyses revealed many sand layers and organic layers, alternating with a few layers of segregated ice. In the raises banks, brown fen peats represent former wet conditions prior to bank uplift. Total ice volumes of the core samples from polygon centres and banks averaged 60%, and were generally in the form of pore ice. Segregated ice was concentrated in ice wedges. The Low gradient of the polygon field and the shallow active layer are responsible for impded drainage. The origins of this isolated low–centred polygon field are discussed in terms of special local terrain conditions. River flooding since glacio–isostatic emergence at 6000 BP repeatedly spread alluvial sands onto the low flood–plain, which thus became progressively built up to its present elevation. Peat layers buried by these alluvial sands have permitted the changing local drainage conditions to be radiocarbon–dated for the last 2600 years for the core sites. Impeded drainage, low winter temperatures, probable thin snow cover, rapid sedimentation of flood–plain sands, and high volumetric ice contents have created the critical thermal regime necessary for repeated frost cracking in a polygonal pattern, with concomitant ice–wedge dev–elopment. Ice wedges developed at least as early as 2200 BP, causing the formation of low banks. Further growth of ice wedges deformed the peat and sand layers on the bank margins and led to the rise of the latter to ... Article in Journal/Newspaper Ice permafrost wedge* Wiley Online Library Canada Boreas 20 3 259 285 |
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Open Polar |
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Wiley Online Library |
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crwiley |
language |
English |
description |
Morphological and vegetation mapping and stratigraphic studies were carried out on a 60 by 250 m low–centered polygon field on a flood–plain of the Riviére Deception in the continuous permafrost zone of northernmost Ungava. Analyses of grain size, water and ice content, deformation structures, and macrorests were carried out on drill–core samples, up to a maximum depth of 3.19 m, and radiocarbon dates were obtained from several peat horizons. Five different vegetational habits were identified: uplifted banks, ice–wedge fissures, hummocky centres, wet polygon centres, and water ponds. The stratigraphic analyses revealed many sand layers and organic layers, alternating with a few layers of segregated ice. In the raises banks, brown fen peats represent former wet conditions prior to bank uplift. Total ice volumes of the core samples from polygon centres and banks averaged 60%, and were generally in the form of pore ice. Segregated ice was concentrated in ice wedges. The Low gradient of the polygon field and the shallow active layer are responsible for impded drainage. The origins of this isolated low–centred polygon field are discussed in terms of special local terrain conditions. River flooding since glacio–isostatic emergence at 6000 BP repeatedly spread alluvial sands onto the low flood–plain, which thus became progressively built up to its present elevation. Peat layers buried by these alluvial sands have permitted the changing local drainage conditions to be radiocarbon–dated for the last 2600 years for the core sites. Impeded drainage, low winter temperatures, probable thin snow cover, rapid sedimentation of flood–plain sands, and high volumetric ice contents have created the critical thermal regime necessary for repeated frost cracking in a polygonal pattern, with concomitant ice–wedge dev–elopment. Ice wedges developed at least as early as 2200 BP, causing the formation of low banks. Further growth of ice wedges deformed the peat and sand layers on the bank margins and led to the rise of the latter to ... |
format |
Article in Journal/Newspaper |
author |
SEPPALA, MATTI GRAY, JAMES RICARD, JEAN |
spellingShingle |
SEPPALA, MATTI GRAY, JAMES RICARD, JEAN Development of low–centred ice–wedge polygons in the northernmost Ungava Peninsual, Queébec, Canada |
author_facet |
SEPPALA, MATTI GRAY, JAMES RICARD, JEAN |
author_sort |
SEPPALA, MATTI |
title |
Development of low–centred ice–wedge polygons in the northernmost Ungava Peninsual, Queébec, Canada |
title_short |
Development of low–centred ice–wedge polygons in the northernmost Ungava Peninsual, Queébec, Canada |
title_full |
Development of low–centred ice–wedge polygons in the northernmost Ungava Peninsual, Queébec, Canada |
title_fullStr |
Development of low–centred ice–wedge polygons in the northernmost Ungava Peninsual, Queébec, Canada |
title_full_unstemmed |
Development of low–centred ice–wedge polygons in the northernmost Ungava Peninsual, Queébec, Canada |
title_sort |
development of low–centred ice–wedge polygons in the northernmost ungava peninsual, queébec, canada |
publisher |
Wiley |
publishDate |
1991 |
url |
http://dx.doi.org/10.1111/j.1502-3885.1991.tb00155.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1502-3885.1991.tb00155.x https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1502-3885.1991.tb00155.x |
geographic |
Canada |
geographic_facet |
Canada |
genre |
Ice permafrost wedge* |
genre_facet |
Ice permafrost wedge* |
op_source |
Boreas volume 20, issue 3, page 259-285 ISSN 0300-9483 1502-3885 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1111/j.1502-3885.1991.tb00155.x |
container_title |
Boreas |
container_volume |
20 |
container_issue |
3 |
container_start_page |
259 |
op_container_end_page |
285 |
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1802645399752671232 |