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Chapter 3: Geologic Structure and Landforms

3.13: Slumping: Souris Gorge Between Souris and Wawanesa

East of Souris the southeastward flowing Souris River takes a right-angled bend to flow northeast 1 through the Tiger Hills moraine in a gorge. The river’s long profile in this area is unusually steep with occasional rapids (2, 3, and 4). The river has incised itself through the surficial glacial deposits and into the underlying Cretaceous shales that appear as light-toned areas on the valley sides 5, 6. Coupled with vertical incision has been lateral movement toward the outside of river bends, leaving behind scars of former higher positions 7. Erosion on the outside of a bend has resulted in a major slump 8 and a smaller one 9. The larger slump flattens the river’s course between two points (10 and 11). The slumped area dams a small south bank tributary 12 to produce a small lake 13.

The valley sides and the hummocky land 14 of the Tiger Hills are covered by deciduous woodland except for some areas cleared for cattle grazing 15. This contrasts with the flat land south 16 and north 17 of the valley that has been cleared for agriculture. These areas are underlain by glacial deposits, and to the north very minor northeast/southwest trending ridges 18 are picked out by the rain splash effect: rain splashes small-sized, dark-coloured fragments from crests, leaving behind coarse light-toned materials. To the west water-filled hollows 19 emphasize this topographic pattern.

Figure 3.13: Slumping: Souris Gorge Between Souris and Wawanesa

Figure 3.13: Slumping: Souris Gorge Between Souris and Wawanesa

Figure 3.13

Vertical air photograph: A11046-57

Flight height: 9,520 feet a.s.l.; lens focal length: 6 inches

Date: May 21, 1947

Scale: 1:15,800 (approx.)

Location: Township 6, Range 18 WI

Map sheets: 1:250,000 62G Brandon

1:50,000 62G/12 Wawanesa