Quaternary History of Northern Cumberland Peninsula, Baffin Island, N.W.T.: Part V: Factors Affecting Corrie Glacierization in Okoa Bay

Abstract

Corries in Okoa Bay contain glaciers, ice patches or are empty. Each of 165 corries is described by 17 variables that describe shape, location and geometry and also have some relationship to the glaciological conditions in each basin. Analyses of these data in terms of “explaining” the factors controlling glacierization (using information and graph-theoretic methods and multiple stepwise discriminant analysis) all emphasize the importance of elevation on the current pattern. Orientation is also significant as virtually all glaciers and ice patches are contained in north-facing corries. Residual elevations from a linear trend surface on corrie lip altitudes indicate that empty corries lie, on average, only 200 m below those currently ice-filled, thus the area is extremely sensitive to the effects of climatic change. Empty corries also lie at the same elevations, on average, in north- and south-facing locations. The orientation of glacierized corries toward the north is a reflection of the variations in insolation between north- and south-facing slopes at latitude 67°30′N. Calculations indicate a difference under clear skies of 25% for global radiation and ∼50% for absorbed short-wave radiation. The 200-m lowering of local snowline implied by the corrie lip data is equivalent to a 1.2°C temperature decrease—this is the same as estimates based on changes in the earth's orbital parameters for this latitude. A lowering of temperature results in an increase in the ratio: sublimation/melting which leads to a reduction in the amount of ablation. It is suggested that glacierization of much of Baffin Island is possible with a lowering of snowline by 200 m, this could then trigger other areas such as Labrador and Keewatin.