GLACIAL LANDFORMS
SHAPE MOUNTAINS
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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
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
GLACIER LANDFORMS OVERVIEW