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 Landforms Glacial 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