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TitlePingos of the pleistocene Mackenzie River Delta area
DownloadDownload (whole publication)
LicencePlease note the adoption of the Open Government Licence - Canada supersedes any previous licences.
AuthorMackay, J R
SourceGeographical bulletin, No. 18, 1962; by Geographical Branch; Canada Department of Mines and Technical Surveys, Geographical Branch, Geographical Bulletin no. 18, 1962 p. 21-63, Open Access logo Open Access
PublisherCanada Department of Mines and Technical Surveys
Mediapaper; on-line; digital
RelatedThis publication is contained in Geographical bulletin, No. 18, 1962
File formatpdf
ProvinceNorthwest Territories
NTS107B/15; 107B/16
AreaEskimo Lakes
Lat/Long WENS-133.2500 -133.0000 69.2500 68.7500
Subjectsmathematical and computational geology; Nature and Environment; Pleistocene; pingos; permafrost; Mackenzie Delta; Geography
Illustrationsphotographs; scatter diagrams
Released1962 11 01
AbstractPingos are stable intrapermafrost ice-cored hills. Most were formed over a thousand years ago as an indirect result of the shoaling of lakes by geomorphic and climatic processes. As the lakes gradually shoaled and lake ice froze to the bottom in winter, an impermeable permafrost cover was formed, ab initio, over the unfrozen saturated sediments beneath. Downward aggradation of the newly formed permafrost cover was predominantly in fine to medium sands which were not susceptible to extensive ice segregation. Consequently, the pressure of expelled pore water, trapped in a closed system, was relieved by an upward doming of the thinnest part of the overlying permafroc,t cover, which normally coincided with the deepest part of the lake. Water in the dome froze to form the pingo ice-core. Calculations based on ground and lake temperatures and the nature of the sediments show that pingo growth was slow, probably involving tens of years for the larger pingos. The large pingos reported in the literature as occurring in the Mackenzie delta are, in fact, not in the modern delta but in Pleistocene sediments to the east. A group of small pingos, which have not been described in detail do, however, occur in the modern delta.

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