Table of Contents
2: Location, Borders, and Lakes
3: Geologic Structure and Landforms
6: Pre-historic and Early Historic Settlements
7: Survey Systems
8: Southern Hamlets, Villages, and Towns
9: Mennonite and Hutterite Settlements
10: First Nations Settlements
11: Northern Settlements
12: The Southern Cities
13: Mining and Oil Extraction
15: Industry / Manufacturing
16: Water Resources
17: Parks, Recreation, Sports
18: Transport and Communications: Past and Present
19: Legal Issues and Law Enforcement
3: Geologic Structure and Landforms
Click for chapter introduction
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 Manitoba are excellent examples of that river form. Several of them have deposited deltas into lakes. The effects of ground water are less easily illustrated, but examples of spring sapping and artesian erosion exist in the south. As all of Manitoba was covered by ice during the latest glaciation, examples of glacial erosion, and especially of glacial deposition, are widespread. Equally impressive are the suite of landforms created by the large glacial lakes that appeared as the ice melted. Glacial spillways, glacial lake deltas, strandlines and flat lake floors are found in many places. Wind action has created dunes on some of the deltas and on glacial outwash deposits. The Hudson Bay coast is rising as a result of isostatic rebound, recovery from the weight of the ice. One result is the existence of strandlines many metres above the level at which they were created. Finally Manitoba’s great lakes are large enough to illustrate many of the landforms normally associated with sea coasts.
[i] Lillesand, T. M. and Kiefer, R. W. Remote Sensing and Image Interpretation (Third Edition). New York: Wiley, 1994, 179.
3.55: The Tiger Hills Near Baldur
The Tiger Hills are part of the Darlingford moraine that runs across southern Manitoba from the Brandon Hills in the west to Pembina Mountain in the east. The hills occupy the central part of this image and are characterized by hummocky terrain, much of which is too hilly for agriculture. Consequently much of the land is left wooded and is dark-toned 1. Depressions are occupied by numerous lakes, some of which are large enough to be named on the 1:250,000 topographic map: McLean Lake 2, the northern part of which is light-toned and the south, dark; Breaults Lake 3; Hoseas Lake 4; and Jones Lake 5. The lakes vary in tone from almost black 6—these are deep with little suspended sediment—to dark grey 7, shallower with suspended sediment, to almost white 8—these illustrate the effect of specular reflection. The ice from which the Tiger Hills moraine was deposited advanced from the north and left behind a series of lobate ridges 9.
North of the moraine is flatland, part of the Assiniboine Delta deposited into glacial Lake Agassiz. Lakes are fewer but one large one, Goodmans Lake 10, can be seen in the north/centre. It is partly unfilled by emergent vegetation. Near the northern edge of the photo is Glenboro Marsh 11 that empties into Oak Creek 12 that flows northwest to the Assiniboine (off the image to the northwest). The lowland occupied by Oak Creek, Glenboro Marsh and Cypress River (just off the northeast corner of the photo) represents the position of a distributary of the Assiniboine at the time the Assiniboine Delta was formed.
On this high-level, small-scale photo the DLS system is obvious especially in areas devoted to agriculture. In the hills, however, the roads cannot always follow section lines as they are forced to detour around lakes 13. Several major route ways can be seen. PTH 23 14 runs east/west and PTH 5 15 north/south across the area. The CN line 16 enters from the southwest and then follows the same route as PTH 23. In the northeast corner a very faint line 17 indicates the position of an underground oil pipeline.
The small Icelandic settlement, Baldur 18, is located south of the hills. It is laid out in grid form with roads parallel and at right angles to both the highway and railway line.
Figure 3.55: The Tiger Hills Near Baldur
Vertical air photo: A21808-64
Flight height: 24,400 feet a.s.l.; lens focal length: 85.55 mm
Date: August 6, 1970
Scale: 1:82,300 (approx.)
Location: Townships 5 and 6; Ranges 13 and 14 WI
Map sheets: 1:250,000 62G Brandon
1:50,000 62G/11 Glenboro