Ninth International Conference on Permafrost ... - IARC Research

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Potential Use of Rock Glaciers as Mountain Permafrost Indicators inYukon Territory, CanadaAmaris PageDepartment of Geography, University of Ottawa, Ottawa, CanadaAntoni LewkowiczDepartment of Geography, University of Ottawa, Ottawa, CanadaIntroductionPanya LipovskyYukon Geological Survey, Whitehorse, CanadaJeff BondYukon Geological Survey, Whitehorse, CanadaAnalysis of the distribution of active rock glaciers iswidely accepted as a way to establish the lower boundaryof mountain permafrost. Rock glaciers have been used inthis capacity for modeling probable permafrost distribution,mainly in Europe (e.g., Imhof 1996, Lambiel & Reynard2001, Frauenfelder 2005, Etzelmüller et al. 2007, Fukui etal. 2007, and others). All of these models have examinedpermafrost distribution over relatively small areas.We are beginning a similar project in Canada’s YukonTerritory. A key difference from previous research is thespatial extent over which the study is being conducted.Currently the distribution of rock glaciers and their activitystatus are being examined in the southern half of the territory,an area of approximately 250,000 km 2 .A second difference between this and the Europeanresearch is that in North America, rock glacier distributionmay represent only the lower limit of high elevationpermafrost. Permafrost also occurs in lower elevation valleybottoms due to a combination of temperature inversionsdue to cold air drainage (Lewkowicz & Ednie, 2004), andecological interactions associated with surface hydrology.This situation does not occur in Europe, where rock glacierdistribution can be used to model the full extent of permafrostin mountainous areas.Our broad goal is to use the distribution of rock glaciersas an independent means of testing mountain permafrostprobability models. This abstract focuses on potentialsources of information and current knowledge of rock glacierdistribution.MethodologyRock glacier location data for this research will be derivedmainly from the Yukon Geological Survey’s surficial geologymaps (see Fig. 1 for map coverage). Rock glacier origins andactivity status will be determined by examining their morphologyon aerial photographs and remotely sensed imagery.Rock glaciers will be classified as active, inactive, or relict.Their distribution will be assessed at various scales andthe usefulness of the rock glaciers for determining probablepermafrost distribution in southern Yukon will be evaluated.A sub-sample of the rock glacier population will be visitedand their origins and activity status verified in the field.Figure 1. Study area showing surficial geology map coverage (white)and distribution of known rock glaciers (black dots) in the YukonTerritory. According to Heginbottom et al. (1995) discontinuouspermafrost becomes continuous at about 64°45′N in this region.Approximately 1650 individual rock glaciers have beenidentified to date on maps at scales of 1:25,000 to 1:250,000,which cover roughly 75% of the Territory south of 65°N (thezones of discontinuous permafrost in the Yukon). Verificationthat the complete population has been mapped will beundertaken for selected areas using aerial photographs.An indication that the maps may not show all the features,possibly because of differences in scale, is that Sloan andDyke (1998) state that more than 1100 rock glaciers arepresent in the Selwyn Mountains alone.Rock glacier density, elevation, and aspect will be comparedin different parts of the Territory. Figure 1 shows that thereis considerable variation in density with most rock glaciersconcentrated in the NW- to SE-trending Selwyn Mountains,Pelly Mountains and Kluane Ranges. Densities in theseareas can reach 1 rock glacier per 4 km 2 . Extraction of other243
Ni n t h In t e r n at i o n a l Co n f e r e n c e o n Pe r m a f r o s tparameters, such as orientation, elevation and dimensions,is in progress. Variability in these will be examined, and thepossibility of their correlation with climate factors will bestudied. From this it is expected that trends in high elevationpermafrost distribution will be evident.Depending on the outcome of the assessment describedabove, the rock glacier inventory may provide the basis fora permafrost distribution model, or it may be used to verifythe results of other models such as those being produced byBTS investigations (Lewkowicz & Ednie 2004, Lewkowicz& Bonnaventure 2008, Bonnaventure & Lewkowicz inreview).ImplicationsThis research is expected to produce the first rock glacierinventory for the southern Yukon, and may additionally beused to create the first permafrost probability map basedon geomorphic indicators in the same region. Large-scalepermafrost distribution mapping has thus far been carriedout using only very general interpolation between existingclimate stations with only qualitative consideration oftopography (Heginbottom et al. 1995). This project aims tocompare methods, improve accuracy, and develop a meansof including topographic effects in Canadian permafrostmapping.Imhof, M. 1996. Modelling and verification of thepermafrost distribution in the Bernese Alps (WesternSwitzerland). Permafrost and Periglacial Processes7(3): 267-280.Lambiel, C. & Reynard, E. 2001. Regional modelling ofpresent, past and future potential distribution ofdiscontinuous permafrost based on a rock glacierinventory in the Bagnes-Hérémence area (WesternSwiss Alps). Norsk Geografisk Tidsskrift – NorwegianJournal of Geography, 55(4): 219-223.Lewkowicz, A. & Bonnaventure, P.P. 2008. Interchangeabilityof mountain permafrost probability models. Permafrostand Periglacial Processes 19(1): in press.Lewkowicz, A. & Ednie, M. 2004. Probability mapping ofmountain permafrost using the BTS method, WolfCreek, Yukon Territory, Canada. Permafrost andPeriglacial Processes 15(1): 67-80.Sloan, V. & Dyke, L. 1998. Decadal and millennial velocitiesof rock glaciers, Selwyn Mountains, Canada.Geografiska Annaler, 80A(3-4): 237-249.AcknowledgmentsThis research is being funded by the Canadian Foundationfor Climate and Atmospheric Sciences.ReferencesBonnaventure, P.P. & Lewkowicz, A.G. (in review).Mountain permafrost probability mapping using theBTS method in two climatically dissimilar locations,northwest Canada. Canadian Journal of EarthSciences.Etzelmüller, B., Farbrot, H., Gudmundsson, Á., Humlum,O., Tveito, O.E. & Björnsson, H. 2007. The regionaldistribution of mountain permafrost in Iceland.Permafrost and Periglacial Processes 18(2): 185-199.Frauenfelder, R. 2005. Regional-scale Modeling of theOccurrence and Dynamics of Rockglaciers and theDistribution of Paleopermafrost. SchriftenreihePhysische Geographie Glaziologie undGeomorphodynamik, 45, Geographisches Institut derUniversität Zürich; Zürich.Fukui, K., Fujii, Y., Mikhailov, N., Ostantin, O. & Iwahana,G. 2007. The lower limit of mountain permafrost in theRussian Altai Mountains. Permafrost and PeriglacialProcesses 18(2): 129-136.Heginbottom, J.A., Dubreuil, M.A. & Harker, P.T. 1995.Canada – Permafrost. 1:7,500,000 scale map. NationalAtlas of Canada (5 th ed.). Natural Resources Canada.244
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ContentsPreface ...................
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Mapping and Modeling the Distributi
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Satellite Observations of Frozen Gr
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xiiIce Wedge Thermal Regime in Nort
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xivPermafrost Response to Dynamics
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NICOP SponsorsUniversitiesUniversit
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Deep Permafrost Studies at the Lupi
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Effect of Fire on Pond Dynamics in
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Cryological Status of Russian Soils
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Acoustical Surveys of Methane Plume
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Permafrost Delineation Near Fairban
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Preparatory Work for a Permanent Ge
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A Provisional Soil Map of the Trans
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Martian Permafrost Depths from Orbi
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Time Series Analyses of Active Micr
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Impact of Permafrost Degradation on
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DC Resistivity Soundings Across a P
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Modeling Thermal and Moisture Regim
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A Provisional Permafrost Map of the
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Alpine Permafrost Distribution at M
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Cryogenic Formations of the Caucasu
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Modeling Potential Climatic Change
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A Hypothesis: A Condition of Growth
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Modeled Continual Surface Water Sto
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Freeze/Thaw Properties of Tundra So
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Discontinuous Permafrost Distributi
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Thermal Regime Within an Arctic Was
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Seasonal and Interannual Variabilit
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Twelve-Year Thaw Progression Data f
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Continued Permafrost Warming in Nor
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Landsliding Following Forest Fire o
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A Permafrost Model Incorporating Dy
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Seasonal Sources of Soil Respiratio
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Greenland Permafrost Temperature Si
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The Importance of Snow Cover Evolut
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The Account of Long-Term Air Temper
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The Combined Isotopic Analysis of L
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Adaptating and Managing Nunavik’s
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Human Experience of Cryospheric Cha
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HiRISE Observations of Fractured Mo
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A Soil Freeze-Thaw Model Through th
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Mapping and Modeling the Distributi
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First Results of Ground Surface Tem
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Historical Changes in the Seasonall
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Rock Glaciers in the Kåfjord Area,
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Snowpack Evolution on Permafrost, N
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Climate Change in Permafrost Region
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Maximizing Construction Season in a
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Pleistocene Sand-Wedge, Composite-W
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