GLACIAL LANDFORMS SHAPE MOUNTAINS Surface features subglacial erosional

GLACIAL LANDFORMS SHAPE MOUNTAINS • • Surface features subglacial erosional depositional

1) Glacier travel: Surface features Crevasses: – V-shaped structures found in the uppermost layer of the glacier. WHY? – brittle deformation – Rarely > 20 m deep

Accumulation area is often heavily crevassed Direction of flow New Zealand

Bergschrund: crevasse that separates flowing ice from stagnant ice at the head of a glacier Glacier on Shorong Yul-lha, Nepal

Icefall: steep, cracked and jumbled ice flows over a drop-off - fast moving!!!! Khumbu Ice fall, Everest

Ogives: alternate bands of light and dark ice on a glacier

Séracs: • Ice towers • Formed by intersecting crevasses, • rapid flow • steep slopes Glacier des Bossons, French Alps photo: MH

Penitentes: spiky columns of snow; formed in dry environments Nev. Coropuna, Peruvian Andes

Melt stream: Glacier can have streams on their surface!! Moulins Very slushy and slippery!! water

SUB-GLACIAL STREAMS

ICE CAVE AT BOTTOM OF GLACIER Pastoruri, Peru

EROSIONAL LANDFORMS OVERVIEW

CIRQUE • a semicircular or amphitheater -shaped bedrock feature created as glaciers scour back into the mountain. • This is where the snow and ice forming the glacier first accumulates.

HANGING GLACIER Occur in tributary glaciers, cause spectacular waterfalls

ARÊTE • steep-sided, sharp-edged bedrock ridge formed by two glaciers eroding away on opposite sides of the ridge

HORN • a pyramid-shaped mountain peak created by glaciers eroding away at different sides of the same mountain.

COL • a low spot or pass along a cirque or an arete.

GLACIAL POLISH Result of abrasion by sand at bottom of glacier

STRIATIONS • result of individual particles embedded in the glacier scratching the underlying bedrock. • lines indicate the orientation of glacial flow.

NUNATAK • Peak surrounded by glaciers but not itself glaciated

TARN • a glacial lake produced by scouring • often found in cirques.

U-shaped valleys • a glacially eroded valley • large, flat valley bottom

ROCHE MOUTONNÉE sheepback , or sheep rock large rock knob that resembles a grazing sheep

DEPOSITION LANDFORMS

Moraines • an accumulation of unconsolidated material deposited by glaciers • unsorted material (different sizes of particles) particles deposited in moraines • material has angular edges.

TERMINAL OR END MORAINE • deposited at the snout end of a glacier • marks the furthest advance of a glacier • caused as a glacier retreats End morraine