Page 582 - Geosystems An Introduction to Physical Geography 4th Canadian Edition

546 part III The earth–atmosphere interface
▼Figure 17.11 The geomorphic handiwork of alpine glaciers. as the glaciers retreat, the new landscape is unveiled. inset photos are surface and aerial views from norway. [Photos by Bobbé Christopherson; waterfall by robert Christopherson.]
Horn
Paternoster lakes
Arête
Col
Glacial erratics
Postglacial
Hanging waterfall
Hanging valley
Cirques
U-shaped glacial trough
U-shaped valley
U-shaped valley, aerial
Tarn
Hanging waterfall
Tarn
U-shaped valley
below sea level. As the glacier retreats, the trough floods and forms a deep fjord in which the sea extends inland, filling the lower reaches of the steep-sided val- ley (Figure 17.13). The fjord may be flooded further by rising sea level or by changes in the elevation of the coastal region. All along the glaciated coast of Alaska, retreating alpine glaciers are opening many new fjords that previously were blocked by ice. Coastlines with notable fjords include those of Norway (Figure 17.14), Chile, the South Island of New Zealand, Alaska, and British Columbia.
Fjords also occur along the edges of Earth’s ice sheets. In Greenland, rising water temperatures in some of the longest fjord systems in the world appear to be ac- celerating melt rates where the glaciers meet the sea. In Antarctica, recent use of ice-penetrating radar identified numerous fjords beneath the Antarctic Ice Sheet, indicat- ing that the present ice sheet was smaller in areal extent in the past.
▲Figure 17.12 Erosional features of alpine glaciation. How many erosional glacial features can you find in this photo of the Chugach Mountains in alaska? See Critical Thinking 17.1. [Bruce Molnia, USgS.]