Quarternary History of Northern Cumberland Peninsula, Baffin Island, N. W. T., Canada: Part IV: Maps of the Present Glaciation Limits and Lowest Equilibrium Line Altitude for North and South Baffin Island

Abstract

Maps of the glaciation limit and lowest equilibrium line altitude (ELA) are presented for southern and northern Baffin Island. The glaciation limit was determined by the “summit method”; the ELAs were determined by assuming a steady state accumulation area ratio of 0.65. Data was derived from the 1:250,000 map series based on between six and eight points per map. The isoglacihypses are roughly parallel to the east coast of the island and rise inland at approximately 4 m km^-1. Along the outermost coast a typical elevation is 700 m a.s.l. rising to between 1,000 and 1,300 m inland. There is evidence on the northern map that the glaciation limit declines from a high point to both the east (Baffin Bay) and the west (Foxe Basin). Enclosed, high contours exist in the vicinity of the Penny Ice Cap, the Barnes Ice Cap, and the heavily glacierized region near Pond Inlet and Bylot Island. ELAs are, on the average, 200 m below the glaciation limit. A study of features in Okoa Bay indicates that paleo-ELAs were once about 400 m lower than today during the late Quaternary. Analysis of the height of the average July 0°C isotherm, assuming an environmental lapse rate of 0.75°C per 100 m, indicates considerable variation on the initial analysis although subsequent work indicates that the relationship between the glaciation limit and the height of the July freezing level has broad, spatial correlation. Glaciation limit gradients from Norway, British Columbia, Greenland, and Baffin Island are compared and shown to be similar with a gradient of about 4 m km^-1.