Glaciers and Glacial Mechanics. I.Glacier Origins and Types.
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Transcript of Glaciers and Glacial Mechanics. I.Glacier Origins and Types.
Glaciers and Glacial Mechanics
I. Glacier Origins and Types
I. Glacier Origins and TypesA. Glacier (def): a body of moving ice that has been formed on
land by compaction and recrystallization of snow.
I. Glacier Origins and TypesA. Glacier (def): a body of moving ice that has been formed on
land by compaction and recrystallization of snow.
B. Critical Requirements
B. Critical Requirements1. Must be formed from the accumulation and ‘metamorphism’
of snow.
B. Critical Requirements1. Must be formed from the accumulation and ‘metamorphism’
of snow.2. Ice must be moving under its own weight.
B. Critical Requirements1. Must be formed from the accumulation and ‘metamorphism’
of snow.2. Ice must be moving under its own weight.3. Must originate on land
B. Critical Requirements1. Must be formed from the accumulation and ‘metamorphism’
of snow.2. Ice must be moving under its own weight.3. Must originate on land4. Persist from year-to-year
I. Glacier Origins and TypesC. The recrystallization of snow
II. The Movement of Glaciers
II. The Movement of GlaciersA. Basal Sliding
II. The Movement of GlaciersA. Basal SlidingB. Plastic Flow
II. The Movement of GlaciersA. Basal SlidingB. Plastic FlowC. Internal Shearing
II. The Movement of GlaciersD. Crevassing (Zone of Fracture)
Crevasses
Crevasses
III. The Glacial Budget• Zone of Accumulation• Zone of Ablation• Equilibrium Line
“fastest velocity atequilibrium line”
IV. Classification of Glaciers
IV. Classification of GlaciersA. Descriptive-basedB. Process-based
IV. Classification of GlaciersA. Descriptive-based
* Cirque Glaciers* Valley Glaciers* Ice Sheets
IV. Classification of GlaciersA. Descriptive-basedB. Process-based
1. Dynamic classification scheme* Active* Passive* Dead
IV. Classification of GlaciersA. Descriptive-basedB. Process-based
1. Dynamic classification scheme* Active* Passive* Dead
2. Thermal classification scheme* Temperate Glaciers
IV. Classification of GlaciersA. Descriptive-basedB. Process-based
1. Dynamic classification scheme* Active* Passive* Dead
2. Thermal classification scheme* Temperate Glaciers* Polar Glaciers
--sub polar--high polar
V. Erosional Glacial Landforms
CirquesTarn LakesPater Noster Lakes
HornsAretes
U shaped ValleysHanging ValleysFjords
Cirques
Arete
U-shaped valley
Horn
Fjords
Moraines Lateral Medial
VI. Depositional Landforms
Glacial Till
VI. Depositional Landforms
Stratified drift
Lateral and Medial Moraines
Moraines……End, Terminal, Ground
End Moraine
Terminal moraine
Eskers, Drumlins, Kames, Kettles, Outwash Plains, Erratics
Drumlin
Esker
Outwash plain
The Pleistocene Epoch
Milankovitch Cycles
EccentricityTiltingWobble
The Pleistocene Ice Ages:Glacial Periods
WisconsinanIllinoianKansanNebraskan
Global sea level drop
Pluvial Lakes
J. Harlen Bretz1923-1932