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TitreThe Great Slave Lowland: the legacy of Glacial Lake McConnell
AuteurWolfe, S A; Morse, P D; Kokelj, S V; Gaanderse, A J
SourceLandscapes and landforms of western Canada; par Slaymaker, O (éd.); World Geomorphological Landscapes 2016 p. 87-96, 5
Séries alt.Secteur des sciences de la Terre, Contribution externe 20140375
ÉditeurSpringer International Publishing
Documentpublication en série
Mediapapier; en ligne; numérique
Formatspdf (Adobe® Reader®)
ProvinceTerritoires du Nord-Ouest
SNRC85I/03; 85I/04; 85I/05; 85I/06; 85I/11; 85I/12; 85I/13; 85I/14; 85J; 85K/01; 85K/02; 85K/03; 85K/06; 85K/07; 85K/08; 85K/09; 85K/10; 85K/11; 85K/14; 85K/15; 85K/16; 85N/01; 85N/02; 85N/03; 85N/06; 85N/07; 85N/08; 85N/09; 85N/10; 85N/11; 85O/01; 85O/02; 85O/03; 85O/04; 85O/05; 85O/06; 85O/11; 85O/12; 85P/03; 85P/04
Lat/Long OENS-117.5000 -113.0000 63.7500 62.0000
Sujetsantecedents glaciaires; glaciation; déglaciation; lacs glaciaires; niveaux d'eau; emersion; pergélisol; glace fossile; lentilles de glace; caractéristiques périglaciaires; végétation; dépôts organiques; tourbières; sols; argiles; silts; climat; temperature; affaissement; glissements; analyses thermiques; regimes thermiques; Lac glaciaire de McConnell; Bouclier Canadien; Calotte glaciaire Laurentide; sédiments glaciolacustres; sédiments lacustres prélittoraux; buttes cryogènes; forêt; limites de submersion, glaciolacustre; changement climatique; géologie des dépôts meubles/géomorphologie; géologie de l'environnement; Nature et environnement; Phanérozoïque; Cénozoïque; Quaternaire
Illustrationslocation maps; geoscientific sketch maps; photographs; profiles; schematic representations
ProgrammeGéosciences de changements climatiques, Infrastructures terrestres
Diffusé2016 12 02
Résumé(disponible en anglais seulement)
The Great Slave Lowland of the Taiga Shield is an 11,000 km2 low-elevation granitic bedrock plain along the north shore of Great Slave Lake, Northwest Territories. It is characterized by a mosaic of coniferous and deciduous forest cover, wetlands, sparsely vegetated bedrock outcrops, and peatlands. The region was glaciated until about 13,000 years ago and then inundated by Glacial Lake McConnell and by ancestral Great Slave Lake, which gradually declined towards the present lake elevation. Consequently, fine-grained glacilacustrine and nearshore lacustrine sediments are broadly distributed across the region. Permafrost is widespread within forest-covered sediments and peatlands, but is not sustained beneath bedrock outcrops, leading to an extensive, but discontinuous, permafrost distribution. Lithalsas, which are permafrost mounds up to 8 m in height and several hundred metres in length, are also abundant. These form by ice segregation within mineral soil, as permafrost aggrades into the fine-grained sediments following lake level recession. Lithalsas are most common within the first few tens of metres above the present level of Great Slave Lake, indicating that many are late Holocene in age and some <1000 years. These elevated surfaces favour the establishment of deciduous forests with thin organic ground cover and with mean annual ground temperatures typically between -0.5 and -1.5 °C. With annual mean air temperatures consistently warming since the 1940s, this terrain is vulnerable to thawing and subsidence, with impacts on the ecology, hydrology, and population of the region.