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Chapter 3: Geologic Structure and Landforms

3.7: Bedrock Plateau North of Grand Rapids

This air photo shows carbonate rocks (limestone, dolomite) and discontinuous shallow wave-modified till over flat-lying carbonate rocks.[i]

Silurian rocks of the Interlake Group underlie a plateau—the Mamowkiyan Ridge—1 whereas Ordovician rocks underlie the marshy land to the west 2. The large water body, Melhiso Lake 3, drains by Eating Point Creek 4 to the west shore of Lake Winnipeg 5 north of Eating Point Creek 6. Beach ridges created when Lake Winnipeg was at a higher level outline the eastern and northern edge of the plateau 7. In the south is the large Saskatchewan River 8 shown emptying into Lake Winnipeg before the construction of the Grand Rapids Dam in the area.

Figure 3.7: Bedrock Plateau North of Grand Rapids

Figure 3.7: Bedrock Plateau North of Grand Rapids

Figure 3.7

Vertical air photograph: A13935-52

Flight height: 35,000 feet a.s.l.; lens focal length: 152.15 mm

Date: October 28, 1953

Scale: 1:68,000 (approx.)

Location: Township 49, Range 13 WI (Part of Grand Rapids, Local Government District)

Map sheet: 1:250,000 63G Grand Rapids

1:50,000 63G/3 Grand Rapids



[i] Information from Mollard, J. D. Landforms and Surface Materials of Canada (Third Edition). Regina: Commercial Printers, n.d., plate 12 18b.