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Chapter 3: Geologic Structure and Landforms

3.82: The Polonia Trench Northeast of Minnedosa

The area shown is on the southeastern flank of the Riding Mountain upland. The history of deglaciation of the Riding Mountain area is complicated with a series of glacial lakes forming and then emptying generally to the south and in the process creating spillways now occupied by misfit streams. Shown here is the Polonia trench 1 (bounded by dashed lines). The trench, up to 200 feet (60 m) deep, trends north-northeast/south-southwest, parallel to the Riding Mountain escarpment just off the photo to the east. The tiny Neepawa Creek 2 now occupies it. The eastern spillway wall is steep and mainly wooded 3, whereas the west wall is less steep, more dissected by tributary valleys 4, and less wooded. The spillway floor, although not absolutely flat, is flat enough to be cleared for agriculture. This has resulted in severe soil erosion, especially east of Neepawa Creek. Sediment eroded from above has been deposited in a series of small alluvial fans 5. Outside the spillway is hummocky ground moraine topography which produces marginal agricultural land so that sizeable areas are left wooded 6.

A strategically placed microwave tower 7 is located at the top of the east wall of the spillway. By careful inspection of the original photograph using a magnifying lens, both the tower (radially displaced out from the centre point of the photo) and its shadow, falling to the north-northwest, can be seen on the original photo. The shadow direction indicates that the photo was taken after noon. PR 265 8 runs through the area and the hamlet of Polonia 9. The Ukrainian Catholic Church 10 in Polonia serves a large area along the southern edge of Riding Mountain. A shrine located at the church attracts hundreds of people during an annual pilgrimage in the summer.

Figure 3.82: The Polonia Trench Northeast of Minnedosa

Figure 3.82: The Polonia Trench Northeast of Minnedosa


Figure 3.82

Vertical air photograph: A25800-39

Flight height: 9,900 feet a.s.l.; lens focal length: 152.034 mm

Date: July 5, 1981

Scale: 1:17,600

Location: Township 16; Range 16 WI

Map sheets: 1:250,000 62J Neepawa

1:125,000 62J/SW Neepawa

1:50,000 62J/5 Clanwilliam