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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
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GLACIAL LANDFORMSSHAPE 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 water Very slushy and slippery!!
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
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
LATERAL MORAINE • unconsolidated material • deposited along the • sides of an alpine glacier. 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