Alpine glacier- Alaska

Report
Surface Processes
weathering, mass wasting, erosion, deposition
GLACIER MOVEMENT
SIMILARITIES
Alpine and continental glaciers are the same in
the way in which the ice moves -----
It is like a slow conveyer belt. Snow enters the
glacier at the top or head, becomes compacted
and eventually converted to ice. Ice under
pressure will flow.
Alpine glaciers flow down hill continental
glaciers flow from thick areas to thin areas.
DIFFERENCES
ALPINE VS. CONTINENTAL
• Alpine glaciers leave very rugged sharp peaks
• Continental glaciated leave rounded and flat
areas
Alpine glacier- Alaska
Alpine/valley glacier Alaska
Alpine glacier Mt. Rainier
Continental glacier –Mt. Katadin ME
rounded mountain top
Glacier - Alaska
TYPES OF GLACIAL MATERIAL I
A. SORTED
WATER deposited (glacial-lacustrine)
Ex. Kames, eskers (geomorphic
features)
Outwash plains
WIND deposited sediments near the ice
margins
Ex. Loess deposits
DEPOSITIONAL FEATURES OF
GLACIERS ( NAMES of FEATURES)
• Moraines- end, lateral, recessional, ground,
interlobate --- piles of unsorted material
• Kames- delta, terrace, moulin---mounds of
sorted material
• Eskers--- long snake like features of sorted
material
• Outwash plains---- flat expanses of fine material
washed from the base of a glacier
Glacial processes and features applied to
continental glaciers
Depositional features of Continental glaciers
Glacial Ice Alaska
Alpine Glacier-Mt Rainier
Glacial-Fluvial (Kame) deposit Germantown WI
Braided stream- at terminus of glacier
Moulin Kame-Pike Lake WI
Formation of one type of Kame
Holy Hill WI - Moulin Kame
Myra Esker near West Bend WI
Kettle Moraine Area
Gilbert lake WI Cobblestone House
TYPES OF GLACIAL MATERIAL II
• B. UNSORTED GLACIAL MATERIAL
Indicates direct contact with ice, moved by the
ice
Ex. Till ---- which makes up moraines
All moraines are basically till
But you can find glacial- lacustrine
Deposits with the moraines
Typical Shoreline Material in S.E.
Wisconsin: gray till , red till, and sand
EROSIONAL FEATURES OF GLACIERS
Striations
Rounding of bedrock
U shaped valleys (alpine)
Potholes
Potholes – Taylor Falls MN
Produced by glacial meltwater
GLACIAL EROSION- ROUNDED
SURFACES
GLACIAL STRIATIONS
DRUMLINS
Depositional and Erosional ?
• Elongated in the direction of the ice.
• Not found everywhere ( Wisconsin and
New York state have several drumlin fields)
• Can be composed of rock, till, or sorted
sediments.
• Suggests they could be the result of glacier
advancing over former deposits
Drumlin Camblesport WI
Drumlins
in Jefferson
Co.
Drumlin in Jefferson Co.
Inside the Drumlin
Shape of Drumlin
GLACIAL AGES
(ADVANCES AND RETREATS)
•
•
•
•
TRADITIONAL NAMES
Nebraskan 1,000,000 - 2,000,000 yrs ago
Kansanan 400,000 yrs. Ago
Illinoisan 115,000 yrs. Ago
Wisconsinan ( 65,000 years - 10 ,000 years ago
CURRENT NAMES
•
Pre-Illinoisan
•
Illinoisan
•
Wisconsinan past 100,000 years. Most complete
history starting about 26,000 years B.P.
EXTENT OF GLACIATION
The Wisconsin glaciation covered a great part of
the eastern u.S. It extended to the east coast and
formed such places as long island, cape cod
And block island.
The rocky mts. Were also exposed to the glacial
ice, but in the form of alpine glaciation. The great
ski resorts are located in the glacial valleys.
(Wisconsinites on the other hand ski mostly on
glacial deposites)
EXTENT OF LAST GLACIATION
OTHER FACTS ABOUT CONTINENTAL
GLACIERS
A . Ice was 1 to 2 miles thick at its central point (in
Canada)
B. Sea level dropped by 200-300 ft. Because so much
water was taken up in ice.
C. Glaciers erode material from the middle of its
course and deposit it at the end.
D.Wisconsin driftless area - no glaciation
during Wisconsinan glaciation ? cause?
GLACIAL EROSION AND DEPOSITION
POINTS OF GREAT INEREST IN
WISCONSIN RELATING TO
GLACIERS!
1. Glacial lake Wisconsin--- Cranberry bogs
2. Driftless area
3. Wisconsin dells
Driftless
Area WI
MOST IMPORTANT TO US IN SE
WISCONSIN
1. Lake Michigan lobe
2. Green Bay lobe
3. Soils / tills left by these glacial advances
4. The problems of lake shore erosion caused
by the glacial - lacustrine materials--Grant
Park as an example
5. Old beach levels or shorelines – Drs Park,
Beach Dr., Audubon Center
6. Mineral resources of sand and gravel
POSSIBLE CAUSES OF GLACIATION
A. Variation in the rotation of the earth
B. Variation in the solar output
C. Plate tectonics
D. Volcanism

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