FROST HEAVE IN LAKE-BOTTOM SEDIMENTS, MACKENZIE DELTA, NORTHWEST TERRITORIES.
The frost-heave regime of lake-bottom sediments has been studied during winters 1987-88 and 1988-89 at a lake connected seasonally with the Mackenzie River near Inuvik. N.W.T. Sub-ice frost heave was measured with telescoping tubes and by precise levelling; the lake-bottom thermal regime was monitor...
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| Language: | English |
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.529.5953 http://pubs.aina.ucalgary.ca/cpc/cpc5-103.pdf |
| Summary: | The frost-heave regime of lake-bottom sediments has been studied during winters 1987-88 and 1988-89 at a lake connected seasonally with the Mackenzie River near Inuvik. N.W.T. Sub-ice frost heave was measured with telescoping tubes and by precise levelling; the lake-bottom thermal regime was monitored with thermistor cables. Air temperatures were similar during both winters, but a thinner snowcover during 1988-89 led to thicker primary ice. greater frost penetration into lake-bottom sediments. and greater frost heave than during 1987-88. In 1988-89, maximum measurements of ice thickness. frost penetration and frost heave were 77 cm, 180 cm and 30 cm respectively. About 10 % of segregational frost heave occurred in frozen sediment some distance above the frost front. W i g 1987-88 lake water, under pressure due to recharge, was injected into freezing sediment to form intrusive ice. Little evidence of intrusive ice was found in 1988-89 because recharge was lower than during 1987-88. Le regime de soulkvement par le gel des sddiments de fond de lac a Bd BtudiB au cows des hivers 1987-88 et 1988-89. dam un lac rattach6 annuellement au Fleuve Mackenzie prks d'Inuvik. T.N-0. Le soul&vement par le gel sous la glace a Bd mesurC au moyen de tubes dlCscopiques et par nivellement de prkision; le rBgime thermique du fond lacustre a C d suivi 8 l'aide de cibles 8 thermistors. Les tern~ratures de l'air Btaient semblables pendant les deux hivers, mais une couvertme nivale mince en 1988-89 a favorid la croissance d'une glace plus Bpaisse, une &itration plus profonde du gel dam les &ments lacustres, et un soulkvement par le gel plus important que pendant 1987-88. En 1988-89. les mesures maximales de 1'Bpaisseur de la glace. de la p6nBtration du gel. et du soulkvement par le gel ont 6d de 77 cm. 180 cm et 30 cm. Environ 10 % du soulevement par le gel s'est produit par sBgr6gation de glace dans les ddirnents gel & 8 quelque distance au dessus du front de gel. En 1987-88 de l'eau lacustre, pressuriske par le ... |
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