The absence of igneous and metamorphic clasts of Canadian Shield origin in the Saskatchewan gravels and sands (preglacial) valley fills in seven active gravel pits studied over a 5 yr period, coupled with 29 radiocarbon dates (21,300-42,910 yr B.P.), suggest that Laurentide glaciation prior to the late Wisconsin did not reach the Edmonton area. On the basis of Edmonton's elevation (∼670 m above sea level [asl]), compared to higher regional elevations to the south (Calgary, ∼1060 m asl), and maps of the retreat pattern of late Wisconsin Laurentide ice (which we equate approximately with advance pattern), it is likely that large areas of higher elevation in Alberta, south and west of Edmonton, only underwent the late Wisconsin event, not multiple glaciations.

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