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
3.30: The Assiniboine River in Spruce Woods Provincial Park
As in Figure 3.29 the
In the southeast a combination of spring sapping and slumping has produced a series of embayments 9, and both north and south of the river are water-eroded dry ravines 10. Stabilized sand dunes exist on both sides of the river, with one small patch of open sand 11.
A small area mainly on the floodplain has been cleared for agriculture 15. Only a few farm trails penetrate the area 16.
Figure 3.30: The Assiniboine River in Spruce Woods Provincial Park
Vertical air photograph: 15577-20
Flight height: 20,000 feet a.s.l.; lens focal length: 153.09 mm
Date: October 11, 1956
Scale: 1:37,900 (approx.)
Location: Townships 8 and 9, Ranges 12 and 13 WI
Map sheets: 1:250,000 62G Brandon
1:50,000 62G/11 Glenboro
[i] Rogosin, A. “The Spruce Woods Sandhills” in Wested, Everitt, and Stadel, op. cit. 1996, 56-59.