| Titre | Characteristics of discontinuous permafrost from ground temperature measurements and electrical resistivity tomography, southern Yukon, Canada |
| Auteur | Lewkowicz, A G; Etzelmuller, B; Smith, S L |
| Source | Permafrost and Periglacial Processes 2011, 23 pages, https://doi.org/10.1002/ppp.703 |
| Année | 2011 |
| Séries alt. | Secteur des sciences de la Terre, Contribution externe 20100083 |
| Éditeur | Wiley |
| Document | publication en série |
| Lang. | anglais |
| DOI | https://doi.org/10.1002/ppp.703 |
| Media | en ligne; numérique; papier |
| Formats | pdf |
| Province | Yukon |
| SNRC | 105C; 105D; 115O |
| Lat/Long OENS | -136.0000 -132.0000 61.0000 60.0000 |
| Lat/Long OENS | -140.0000 -138.0000 64.0000 63.0000 |
| Sujets | pergélisol; congélation du sol; glace fossile; températures au sol; résistivité électrique; résistivité; climat arctique; climat; fluctuations climatiques; Changement climatique; géologie des dépôts
meubles/géomorphologie; géophysique; géologie de l'environnement |
| Illustrations | location maps; tables; profiles; photographs |
| |
| Programme | Les sciences de la Terre à l'appui de la caractérisation, à l'échelle nationale, des impacts des changements climatiques sur la masse continentale canadienne, Géosciences de changements
climatiques |
| Résumé | (disponible en anglais seulement)
Warm permafrost conditions (mean temperatures of -3°C to -0.1°C) were investigated in detail at 13 valley and mountain sites in the sporadic (10 - 50%) and
extensive (50 - 90%) discontinuous permafrost zones in the southern half of the Yukon (60°N to 64°N), using a combination of ground temperature monitoring, electrical resistivity tomography (ERT), frost table probing and coring. Sites were selected
to cover a wide range of substrates, vegetation types and ground ice contents. ERT profiling in the spring imaged both deep seasonal frost and perennially frozen ground. Deep active layers measured by probing at the end of summer were also detectable
by ERT. Where ground temperatures indicated that the base of permafrost was at a depth of less than 25 m, vertical transitions in apparent resistivity were more sharply defined in coarse materials than in fine-grained deposits, probably because of
differences in unfrozen moisture contents at temperatures just below 0°C. Apparent resistivity values related to excess ice fraction and ground temperatures were similar to those previously obtained in Mongolia and Iceland, but generally lower than
in ice-rich rock glaciers in European studies. The observations revealed the complexity of site conditions where permafrost is discontinuous and the utility of ERT, in combination with other methods, to investigate permafrost thickness, spatial
extent and ice content for infrastructure planning or climate change studies. |
| GEOSCAN ID | 285588 |
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