QUATERNARY STRATIGRAPHY OF THE BURIED VALLEYS OF THE LOWER RED DEER RIVER, ALBERTA, CANADA

The Quaternary fills of the buried valleys of southern Alberta and Sas katchewan have provided a wealth of information for the reconstruction of the glacial-interglacial record of the western plains of Canada, a nd this paper reports on the previously unstudied stratigraphy of the buried Calgary Valley and its former tributaries in the lower Red Deer River area. We attempt to differentiate Empress Group sediments, whic h potentially relate to pre-glacial, interglacial/interstadial and pos t-glacial lake and river deposition, using sedimentology, stratigraphy and palaeoecology. Twenty-nine stratigraphical logs indicate that Emp ress Group sediments have infilled a considerably large area of badlan ds and tributary coulees that once drained into the Calgary Valley, lo cated 15 km to the north of Dinosaur Provincial Park. Radiocarbon date s of 52.4 ka, 27.4 ka and > 42.4 ka and glacially modified quartz grai ns suggest that at least some of the valley fills dale to interglacial or interstadial periods and may be mid-Wisconsinan in age. However, o utcrops of an older till overlying other valley fills suggest that the buried valleys were only partially excavated during interglacials/int erstadials and that older (even pre-glacial) sediments could have surv ived. Subglacial channels, recognisable on air photographs, largely co incide with buried valley positions due to the preferential excavation of the Quaternary sediment by meltwater and are filled with post-glac ial lake sediment from which a radiocarbon date of 16 ka BP was obtain ed. Pre-glacial and glacial/post-glacial Empress Group sediments are l ithologically indistinct but cover a large time span in southern Alber ta.