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Table of Contents
Foreword
Preface
Glossary

Chapter 3: Geologic Structure and Landforms

3.94: Raised Strandlines on the Hudson Bay Coast South of Cape Churchill

The weight of ice that covered Manitoba during the Pleistocene “caused depression of the earth’s crust which rebounded towards its former position once the ice melted. Depression and subsequent rebound was greatest where the ice was thickest. In Manitoba the Hudson Bay lowlands were depressed relative to sea level, resulting in transgression of the sea (called the Tyrrell Sea) as far inland as 200 km from the present shore of Hudson Bay. Strandlines formed along the shore and have since been elevated to heights as much as 183 m on the Manitoba-Northwest Territories [Nunavut] border.”[i]

In this photograph of an area about 15 miles (24 km) south of Cape Churchill, a series of strandlines can be seen running roughly parallel to the coast of Hudson Bay 1. The most prominent strandlines are the highest 2, suggesting that the sea stood at this level for an extended period. Below them are less continuous strandlines 3 formed as the sea retreated in stages. Many lakes exist in the lower land between strandlines. These vary in tone from very dark grey 4 to almost white 5, depending on the lake surface/sun angle/camera angle relationship (the specular reflection effect). The White Whale River reaches the sea in this area 6. Part of its course can be traced back from the coast 7, but further inland it is difficult to follow. Inland from the strandlines is flatland covered by shrub-tundra, although around Klohn Lake 8 in the southwest the dark tone suggests more shrubs 9. This area in which drainage is to the north also includes numerous lakes in various tones 10.

Figure 3.94: Raised Strandlines on the Hudson Bay Coast South of Cape Churchill

Figure 3.94: Raised Strandlines on the Hudson Bay Coast South of Cape Churchill

Figure 3.94

Vertical air photograph: A17406-66

Flight height: 30,000 feet a.s.l.; lens focal length: 88.28 mm

Date: July 31, 1961

Scale: 1: 101,000 (approx.)

Location of the mouth of White Whale River: 58 34'N, 93° 08'W

Map sheets: 1:250,000 54K Cape Churchill

Notes

[i] Corkery, M. T. “Geology and Landforms of Manitoba” in Welsted, Everitt, & Stadel eds. op. cit., 18.