Glacial Landforms 1.Alpine erosional landforms 2.Alpine depositional landforms 3.Continental glacial...

Glacial Landforms

1. Alpine erosional landforms2. Alpine depositional landforms3. Continental glacial landforms

(erosional and depositional

Alpine Glacial Erosional Landforms

cirque

cirque

Tarn

rock bound lake

Tarn (looking down)

horn

Horns havecirques onall sides (Mitre Peak, New Zealand)

U-shaped glacial troughfrom v-shaped river valley

Hanging Valley

Originally

After Ice Melts

Fjord

Iceland

Telluride

Snowbird – Little Ice Age Cirques

Glaciers smooth aretes and allow travel over these col passes

Melting from

Pressure: upside

Polishing onup side

Direction of

Ice Flow

Glacial Grooves

Pluckingrefreezing

around rock

Pluckingrefreezeand pullout

Alpine Depositional Landforms

Boulders,CobbleSand, Silt – where

does it come from?

Mass Wasting, avalanches onto glacier

Erosion along the bed of a glacier

Till – boulders down to clay deposited in contact with a glacier

Deposited in the Ablation Zone

Basic forms, after glacier ablates

Moraines – ridges of till

Lateral moraines – from avalanches on the sides of the glacier

Accumulation ZoneAblation Zone

tarn in cirquelateral moraine

Lateral moraines – evidence whenthe glacier is all gone of its extent

Lateral moraines – deposited in ablation zone

lateral moraines join end moraine

Glaciers are a conveyor belt and moraines are the ‘garbage dump’

animated gif that should play (don’t worry if it does not)

end or terminal moraine (shows maximum extent)

end moraine

end moraine

Recessional Moraine

Laterals join recessional/end moraine

end moraine

laterals come together as medial moraines

Only see medial moraines when glaciers are present (they are destroyed by meltwater streams)

Meltwater streams deposit outwash plains

Fox Glacier, New Zealand

Glacial Erratics – giant boulders left behind: Noah’s flood or ancient ice age?

Religion vs. Science

Continental Glacial Landforms

Biggest Changes (where see evidence)Laurentide ice sheet: eastern N Am.Cordilleran ice sheet: Canadian RockiesEurasian ice sheet: northern EuropeClassroom Resource: Little Change in Antarctica

Biggest Changes

Laurentide ice sheet: eastern N Am.Cordilleran ice sheet: Canadian RockiesEurasian ice sheet: northern Europe

Wisconsin – 20 ka

On the ocean side …icebergs carried glacial sediment into the

Atlantic

Very cold & wetpulses

Gulf Stream further south – so northern Europe froze

Heinrich events -Very cold & wetpulses

Under the Ice

Areas of Scour: rock ground down, plucked, and quarried producing lots of bare rock and lakes

Deep Valley Cutting: large troughs eroded by concentrated abrasion, quarrying and plucking

Areas of Little Erosion: where its so cold that all the pressure can’t melt the bottom ice, cold-based glaciers produce little movement and little erosion

Aerial Scouring: East Antarctica

Aerial Scouring: Ireland

Aerial Scouring: Finland and Newfoundland

Deep Valley

Cutting: Finger Lakes

Deep Scour

Long Island Terminal Moraine

Started with deep scouring, then got complicated

Each of these in turn

End Moraine: Greenland

End of Cordilleran Ice Sheet

Outwash

Till Plain(or ground moraine)

Drumlins

Oriented with flow

Drumlins in Patagonia

Perhaps formed under areas of fast moving ice

Kettle Lakes

Spectacular Outwash: Iceland

Online Resources

Glacier Physics

http://serc.carleton.edu/NAGTWorkshops/visualization/collections/glacier_physics.html

Origin of Glaciation

http://serc.carleton.edu/NAGTWorkshops/visualization/collections/glaciation_origins.html

Glacial Landforms Resulting from Erosion and Deposition

http://serc.carleton.edu/NAGTWorkshops/visualization/collections/glacial_landforms.html

Examples of Deglaciation

http://serc.carleton.edu/NAGTWorkshops/visualization/collections/deglaciation.html