Transcript Alpine glacier- Alaska
Surface Processes weathering, mass wasting, erosion, deposition
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.
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.
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
long snake like features of sorted material
---- 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
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
(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
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