HOLOCENE GEOMORPHOLOGY AND STRATIGRAPHY OF THE LOWER FALCON VALLEY, DINOSAUR-PROVINCIAL-PARK, ALBERTA, CANADA

A tributary of the Red Deer River in Dinosaur Provincial Park, souther n Alberta, contains evidence of a sequence of valley cutting and the d eposition of three alluvial fills and one eolian deposit. With the exc eption of the eolian deposit and minor amounts of Shield and Cordiller an rocks, the sediments are derived from local bedrock. Incision of th e bedrock valley occurred in the early postglacial period about 14 000 - 12 000 BP by rapid drainage of proglacial lakes and meltwaters. The valley was subsequently partly infilled as locally fed stream dischar ges declined during the early to middle Holocene. By 6000-5000 BP allu vial fans had formed along the base of the valley walls. Fan developme nt was followed by two phases of stream entrenchment and alluvial depo sition, including the most recent phase of cutting and filling that be gan approximately 800 BP. The erosional and depositional events may re flect climatic changes as inferred in lacustrine deposits in southern Alberta and in valleys elsewhere in the Great Plains. Glacioisostacy c onditions, however, at least in the early Holocene, may have had profo und effects on stream base levels.