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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 - PowerPoint PPT Presentation
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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 isoften heavily crevassed
New Zealand
Direction of flow
Bergschrund:crevasse that separates
flowing ice from stagnant
ice at the head of a glacier
Glacier on ShorongYul-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 LANDFORMSOVERVIEW
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 MOUTONNÉEsheepback , 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
Lateralmorraine
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