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TitreLithalsa distribution, morphology and landscape associations in the Great Slave Lowlands, Northwest Territories
LicenceVeuillez noter que la Licence du gouvernement ouvert - Canada remplace toutes les licences antérieures.
AuteurStevens, C W; Wolfe, S A; Gaanderse, A J R
SourceCommission géologique du Canada, Dossier public 7255, 2012, 41 pages, (Accès ouvert)
ÉditeurRessources naturelles Canada
Documentdossier public
Cartes1 carte
Info. cartegéologique, 1/166,666
Mediaen ligne; numérique
Formatspdf; shp; rtf
ProvinceTerritoires du Nord-Ouest
SNRC85J/10; 85J/11; 85J/12; 85J/13; 85J/14; 85J/15
Lat/Long OENS-116.0833 -114.4167 62.8833 62.3333
Sujetspergélisol; glace fossile; congélation du sol; glaciation; dépôts glaciaires; végétation; télédétection; géologie de l'ingénieur; géologie des dépôts meubles/géomorphologie; Nature et environnement; Quaternaire; Cénozoïque
Illustrationslocation maps; aerial photographs; tables; photographs; graphs
ProgrammeGéosciences de changements climatiques, Infrastructures terrestres
Diffusé2012 12 05
Résumé(disponible en anglais seulement)
The distribution of ice-rich terrain is an important geotechnical consideration for the engineering of northern infrastructure. Lithalsas represent one form of ice-rich terrain that can be identified on the basis of surface geomorphology and cryostratigraphy. A total of 1,777 ice-rich lithalsas were mapped over 3,680 km2 using monochromatic stereo-pair airphotos, across the Great Slave Lowlands and Uplands, NWT, Canada. Boreholes indicate lithalsas in this region consist of ice-rich silt and clay, with segregated ice lenses up to 10 cm thick. Three distinct morphologies are recognized from LiDAR bare-earth DEMs including; (i) circular, (ii) linear and (iii) crescentic plan-view shapes, which exhibit hill-like or ridge-like forms up to 8 m in height and more than 100 m in width. The linear relationship between lithalsa height and width indicates that 1 cm of vertical growth may be accompanied by 15 cm of lateral growth at the peripheral edges. Lithalsa distribution is skewed towards lower elevations, with 97.7% located within the Great Slave Lowlands. These features predominately occur adjacent to water bodies and follow the regional distribution of frost susceptible glaciolacustrine silt and clay. Landscape associations suggest lithalsa formation is controlled by sedimentological, thermal and hydrological conditions. This Open File reports the first account of lithalsas within this region.