The drift thickness map shows the variation in thickness of unconsolidated sediment lying between the bedrock surface and present-day land surface, and complements the 1995 Drift Thickness of Alberta map by Pawlowicz and Fenton.
Throughout the entire map area, the bedrock is blanketed by drift, with the exception of a few outcrops and thin till veneers along the south flank of the uplands. The drift is also relatively thin (<25 metres) in the Hay River Plain adjacent to the uplands, where glacial erosion was more persistent than deposition. Much thicker drift is found in the buried valleys and beneath portions of the hills in the uplands. Thickest drift of 351 metres was recognized in a well in Township 123 and Range 1 in the Cameron Hills. As well, over 300 metres of drift was found in a number of wells along the major Bistcho paleovalley. The Shekilie Valley is another major paleovalley in the Cameron Hills Uplands and contains slightly less drift of between 200 and 300 metres. The Amber, Moody and Adair valleys are other buried valleys in the south part of the map area; however, drift thickness in these is less than 150 metres.
The bedrock topography map of the Bistcho Lake area shows the location of the major buried valleys. The present-day land surface with great expanses of broad low-lying areas shows little evidence of these buried valleys.
Pawlowicz, J.G., Nicoll, T.J. and Sciarra, J.N. (2007): Drift thickness of Bistcho Lake area, Alberta (NTS 84M); Alberta Energy and Utilities Board, EUB/AGS Map 417