Map 416

Map 416

MAP 416

Bedrock Topography of Bistcho Lake Area, Alberta (NTS 84M)

Author(s) Pawlowicz, J.G. Nicoll, T.J. Sciarra, J.N. Date 2010-12-09

The bedrock topography map shows contours of the elevation of the bedrock surface above sea level, ranging from a low of 215 metres in the SE corner of the map area to greater than 640 metres in Elsa Hill. In general, the major topographic relief in uplands is controlled by the bedrock topography. The surface of the bedrock in the low-lying areas between the hills and in the Hay River Plain is incised by drift-filled paleovalleys with glacial and possibly preglacial sediments. The contoured south flank of the uplands and linear flutes at surface are evidence of erosion and modification by glacial ice (Figure 1; Paulen et al., 2006b; Smith et al., 2005). Major buried valleys are identified on the map by thalweg names. Data from the Bistcho map area, British Columbia and Northwest Territories indicate the gradient of the Shekilie and Bistcho valleys trend northwestward, and likely flowed toward the Mackenzie River valley in the north. The elevation of the lowest part of the Bistcho Valley was determined from well data to be 234 metres above sea level at the northern portion of a major paleovalley that exits the map area to the north. The trend of the Dickins Valley northward from Bootis Hill is based on sparse data, and may have a western tributary that flowed from British Columbia. South of the Cameron Hills Uplands, the gradients of Amber and Moody paleovalleys indicate that flow was toward the south, likely connecting with the Zama paleovalley located beneath Zama Lake in the adjacent map area to the south. The Adair Valley forms part of what was previously interpreted as the Steen paleovalley and trends southeastward through the Hay River Plain. The bedrock elevation in the Adair Valley is 215 metres above sea level at its lowest point and is the lowest elevation in the entire map area.