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Table of Contents
Foreword
Preface
Glossary

Chapter 3: Geologic Structure and Landforms

3.14: Slumping in the Pembina Valley South of Darlingford

At the end of the Wisconsinan ice age, the Pembina Valley carried water from glacial Lake Hind in southwest Manitoba to glacial Lake Agassiz. The water eroded a valley currently over 300 feet (91 m) deep that is now occupied by the misfit Pembina River 1. It is joined from the northeast by a small creek 2, which has etched a deep, v-shaped valley that breaks the continuity of the northeast wall of the spillway. The southwest wall is more continuous and very steep: undercutting by the Pembina has resulted in slumping leaving behind slumped blocks 3 with a dried-up slough in the depressions between the blocks 4. The Pembina meanders on the spillway floor depositing light-toned gravels in many locations 5. A small creek enters from the west 6. The Pembina has abandoned two river segments 7: one cutoff 8 is very recent and another is imminent 9.

The southwest spillway wall, the valley of the northeast creek, and parts of the northeast spillway wall are all wooded (deciduous). Flat lands outside the valleys and some terraces on the northeast spillway wall 10 have been cleared for agriculture. One gravel road 11 and several paths 12 can be seen as well as three farms 13, all of which have shelterbelts to the north and west 14. A dugout 15 is located close to one farm.

Figure 3.14: Slumping in the Pembina Valley South of Darlingford

Figure 3.14: Slumping in the Pembina Valley South of Darlingford

Figure 3.14

Vertical air photograph: A16181-172

Flight height: 10,500 feet a.s.l.; lens focal length: 152.63 mm

Date: July 20, 1958

Scale: 1:18,100 (approx.)

Location: Township 1, Range 7 WI

Map sheets: 1:250,000 62G Brandon

1:50,000 62G/1 Morden