GLACIOLACUSTRINE SEDIMENTS AND NEOGLACIAL HISTORY OF THE CHEPHREN LAKE BASIN, BANFF NATIONAL-PARK, ALBERTA

Modern and historical sedimentation in Chephren Lake are examined in o rder to assess the relations between glacier activity, sediment produc tion, and the lacustrine depositional record. Bottom sediment data and lake morphology indicate that sediments in the distal part of the lak e primarily settled from suspension and that glaciers are the most imp ortant source. A 4.3 m core obtained from the distal sediments reveals that accumulation of fine, glacially-derived material has increased s ince at least 2420 BP. Simple geochemical indicators reflect this and support regional evidence for progressive (though punctuated) climate deterioration through the Neoglacial period. Distinct rhythmite sequen ces (especially beginning ca. 3460, 2330, 1470 and 530 BP) are thought to represent minor glacier retreats which help define separate phases of Neoglacial advance identified by previous workers. In contrast, in creasing slope stability indicated by a reduction in graded sand and c last facies may be specific to slopes overlooking the coring site.