CGRG Bibliography of Canadian Geomorphology
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Author : Gardner, J.S.
Date : 1987
Title : Evidence for headwall weathering zones, Boundary Glacier, Canadian Rocky Mountains
Publication : Journal of Glaciology
Issue : 33(113):
Page(s) : 60-67.
Abstract
Temperature records from several randkluft sites at the margins and headwall of Boundary Glacier in the Canadian Rocky Mountains are presented. These records indicate that during the ablation season a diurnal freeze-thaw air and rock-surface temperature regime occurs in a 2 m wide zone centered on the randkluft lip. Deeper in the randkluft, stable sub-zero conditions prevail whereas above the randkluft an above-freezing temperature regime prevails. The freeze-thaw temperature regime, observed freezing of melt water and rain water on randkluft surfaces, and copious in-situ loose weathering products on the headwall and marginal free faces suggest an active frost-shattering environment. Downslope migration of the randkluft lip during the ablation season results in a migration of the freeze-thaw zone and thus a seasonal extension of the rock surface exposed to the favourable weathering environment. Longer-term glacier fluctuations, with attendant thinning and thickening of the ice body, could result in large areas of marginal and headwall rock surfaces being exposed to the randkluft weathering environment over long periods of time. The data and observations from Boundary Glacier support an idea, suggested by Battle (1960), that open and shallow randklufts, rather than closed and deep bergshrunds, are a focus of weathering at glacier margins and thus a potential factor in cirque development
Bibliography of Canadian Geomorphology