Landforms and Landscapes of Mountain Glaciers
Objectives
• Examine the current distribution of mountain glaciers and to comment on the Late Cenozoic extent of these glaciers
• Describe the characteristic landforms produced by mountain glacier erosion
• Discuss the landforms produced by glacial deposition in mountain landscapes
Global Distribution of Mountain Glaciers • North America– Major clusters lie in the
Arctic islands of Canada, southeastern Alaska, Canada’s Yukon & Coast Mountains of British Columbia, and Canadian Rocky Mountains
• South America– Just south of 45°S in
southern Andes of Chile
Global Distribution of Mountain Glaciers
• Africa– Only two exist• Mt. Kilimanjaro• Mt. Kenya
• New Zealand– Occur in Southern Alps– Several glaciers still exist
around Mt. Cook
Global Distribution of Mountain Glaciers • European Alps– Most famous– Extends from
southeastern France to Swiss-Italian border
– Mont Blanc is highest sitting at 4807 m (15,771 ft)
Global Distribution of Mountain Glaciers
• South-central Asian Alps– Largest mountain system– Extends from
Afghanistan to southwestern China
– World’s highest mountain – Mt. Everest 8850 m (29,035 ft)
Erosional Landforms of Mountain Glaciers
• Glacial Troughs – widening of valley bottom producing a U-shaped valley
Erosional Landforms of Mountain Glaciers• Truncated Spurs– ridge of land is cut off
producing a blunt-ended ridge; caused by erosion of moving glaciers
• Hanging Valley– Tributary valley sits
higher than main valley floor
– Marked by scenic waterfall
Formation of High-Mountain Landforms
• Accumulation of snow• Downslope movement
of ice under gravity• Glacial erosion occurs• Transforms source
areas of glaciers
High-Mountain Landforms
• Cirques – amphitheater-like landform; bowl-shaped, steep-sided depression in bedrock
High-Mountain Landforms• Horn– Multiple cirque develop around mountain peak– Steep-sided, sharp-edged peak remains
High-Mountain Landforms• Aretes– Razor-sharp, jagged
ridges rising above glacial troughs
– Forms at the interaction of two large cirques
• Rock Steps– Step-like profile
formed by differential resistance
High-Mountain LandformsGlacial Lakes are depressions formed by glacial erosion and filled by water during interglacial period•Tarns– Lakes dammed up behind edge of cirque
High-Mountain Landforms
• Fjords– Narrow, steep-sided, elongated ocean inlet– Area where glacial troughs inundated by seawater
Depositional Landforms of Mountain Glaciers
• Rock Flour– Grounded up, fine-grained sediment
• Lateral Moraines– Ridge of debris located along both sides of a glacier
• Medial Moraines– Linear debris marked the boundary between two glaciers
Depositional Landforms of Mountain Glaciers
Postglacial Landscape Change
• Glacial areas are not stable• Modifications are quite rapid• Produce scenic areas
