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Chapter 3: Geologic Structure and Landforms

3.47: Ground Moraine Topography East of Rapid City

The photograph shows part of the Minnedosa-Reston Till Plain.[i] It includes all or part of sections 3, 4, 5, 8, 9, and 10 of township 13, range 18WI and a very small part of sections 32, 33, and 34 of township 12, range 18WI near the hamlet of Moore Park.

A layer of till, the parent materials for which are Cretaceous shale of local origin, Paleozoic limestone and dolomite from the northeast, and Precambrian rocks from the Canadian Shield to the north, covers much of the surface of southwest Manitoba. “These source materials were probably transported in the basal part of the glacier and deposited as sub-glacial till with a thin capping of ablation till.”[ii] The resulting topography has a low amplitude of relief—less that 50 meters—lacks any integrated drainage system, and contains numerous hummocks and depressions; the latter are frequently occupied by small lakes 1—sloughs in local parlance. On this late summer image many of the sloughs have dried up over the summer 2.

The soils developed on the till are generally black chernozems,[iii] but they vary greatly over short distances depending on the topography and drainage. On the higher ground, at the tops of knolls, much of the fine-grained organic material has been removed by a combination of rain splash and wind erosion. The resulting coarse-grained, light-coloured soils appear light-toned on the photograph 3.

The combination of hummocky terrain and rapid soil variation make large-scale farming difficult. In the east 4 and south 5 much of the land is still wooded, but in other areas arable agriculture is practised. Light-toned fields have been planted to cereal crops 6 (probably wheat given the year of the photograph). In some cases harvesting is underway and stooks have been left in fields 7,[iv] and in another case a field has been partly cut 8. Many fields have been left fallow 9, and in these the light-toned hillcrests are especially marked. This area experiences a dry climate, and, as a result, dugouts have been constructed 10 to provide water, principally for farm animals.

Population density is low; only 3 farms 11 can be identified in the area of just over 4 square miles (10.8 square kilometers). The land is divided into sections with gravel roads along some section lines 12 although in one case there is an anomalous jog to the west 13 to avoid a wooded area. The CP railway line in the south 14 was abandoned long ago.

Figure 3.47: Ground Moraine Topography East of Rapid City

Figure 3.47: Ground Moraine Topography East of Rapid City

Figure 3.47

Vertical air photograph: A11677-23

Flight height: 9420 feet a.s.l.; lens focal length: 153.75 mm

Date: September 3, 1948

Scale: 1:15,500 (approx.)

Location: Townships 12 and 13; Range 18 WI

Map sheets: 1:250,000 62J Neepawa

1:50,000 62J/4 Moore Park

1:125,000 62J/SW Neepawa


[i] See Welsted, Everitt and Stadel, op. cit., 1996, figure 2.9, 21.

[ii] Mollard and Janes, op. cit. 1984, 49, writing about ground moraine near Medora.

[iii] See Welsted, Everitt, and Stadel, op. cit. 1996 figure 4.3, 46.

[iv] This is an old method of harvesting no longer used.