Abstract

Measurements of subsurface movement and temperatures from a 17-m bore hole in R.G, II, a rock glacier overlooking Kluane Lake. Yukon Territory, suggest that it is becoming inactive. Present movement appears to be intermediate between a Newtonian viscous flow and one in which velocity decreases exponentially with depth. An older surface has been identified beneath a lobe indicating that the rock glacier has been subject to periods of different rates of activity. Between 1971 and 1976 the internal summer temperatures of all but 1.5 m of the middle section of the bore hole rose to above freezing, and evidence of new thermokarstic development appeared. Although the terminal area of R.G. II appears to have little ice remaining in it, movement is expected to continue by creep until stability is achieved because of the relatively steep bedrock slope on which the rock glacier is situated.

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