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 New Zealand Direction of flow

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

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

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

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

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

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

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

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

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

unconsolidated material deposited along the sides of an alpine glacier. LATERAL MORAINE Lateral morraine

MEDIAL MORAINE When two alpine glaciers flow together, their lateral moraines join, forming a medial moraine

MORAINES: OVERVIEW Medial Moraine

ERRATICS Large boulders left by glaciers in areas where they obviously don’t belong. Can be 10’s to 100’s of kilometers form point of origin

GLACIER LANDFORMS OVERVIEW