View
49
Download
0
Category
Tags:
Preview:
DESCRIPTION
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 - PowerPoint PPT Presentation
Citation preview
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
Recommended