Chapter 3: Geologic Structure and Landforms
Geologic interpretation of images begins with the identification of lineaments, “regional linear features caused by linear arrangement of regional morphological features such as streams, escarpments, and mountain ranges and tonal features that in many areas are the surface expressions of fractures or fault zones.”[i] The emphasis in this section is on geologic structures and landforms, both of which can be easily identified on air photographs and other images.
The sequence followed here is that often found in geomorphology books. Geologic structures and structurally controlled landforms are illustrated first, followed by images of mass wasting and of the results of the agents of erosion—running water, ground water, ice, wind and the sea. The meandering rivers of southern
3.52: The Eastern Ridge of the Brandon Hills
A sharp-crested ridge exists at the east end of the
The flat land is fertile, and most of it is used for crop growth except for some fields that are devoted to animal pasture 8. Harvesting of grain crops is complete, leaving behind distinctive harvesting patterns 9. Very dark-toned fields are those that have been left fallow 10, and even on this very flat land, rain splash and wind erosion have produced light-toned crests on slightly elevated land 11. Six farms 12 exist in this area of 6.25 square miles (16.2 square km). Section lines 13 and quarter section lines 14 are clearly visible; PR 340 15 follows one of the section lines. Railway lines on the other hand do not follow the survey system; the CN line 16, long ago abandoned, connected Brandon and Wawanesa. It takes an unexpected loop in the north 17, possibly to meet the Little Souris River just off the photo, at an appropriate point.
Figure 3.52: The Eastern Ridge of the Brandon Hills
Vertical Air photograph: A16408-10
Flight height: 10,500 feet a.s.l.; lens focal length: 152.63 mm
Date: October 19, 1958
Scale: 1:17,600 (approx.)
Location: Townships 8 and 9; Range 18 WI
Map sheets: 1:250,000 62G Brandon
1:50,000 62G/12 Wawanesa