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Abstract
On air photographs, light-colored areas representing reduced lichen cover indicate the maximum extent of permanent snow cover in the recent past. Lichen-free areas were mapped on 1:50,000, 1:250,000, and 1:1,000,000 map sheets of north-central Baffin Island using air photographs and LANDSAT-1 satellite imagery. Present ice and lakes cover 37% of the study area (97,000 km2). During the Little Ice Age (350 to 100 yr BP), ice and lakes covered about 50% of the study area—an increase of 35%. The amount of lichen-free area is greatest in the elevational range of 450 to 600 m a.s.l.
A limited amount of lichenometrical measurements indicate that the lichen-free areas probably represent a period of more extensive snow cover approximately synchronous with the Little Ice Age.
Paleoglaciation thresholds and paleoequilibrium-line altitudes increased in elevation toward the northeast with lowest elevations southwest of the Barnes Ice Cap. Paleoglaciation thresholds ranged from 500 to 850 m a.s.l. whereas paleoequilibrium-line altitudes ranged from 300 to 900 m a.s.l. Present glaciation thresholds and equilibrium-line altitudes ranged from approximately 100 to 400 m higher than the paleovalues. The difference between present and paleovalues is greatest over the mountainous east coast and decreases to the west.