glacial processes and...

GLACIAL PROCESSES

AND LANDFORMS

1. Formation of glacier ice

2. Glacier motion and crevasse formation

3. Glacial erosion processes and landforms

4. Landforms of glacial deposition

5. “Eiszeit”: past climates and glacial periods

Present-day snowline LGM snowline

Source: Broecker & Denton, 1990.

2 basic types of glaciers:

Continental glaciers (ice sheets)

Alpine glaciers

Cirque glaciers

Valley glaciers

The Antarctic ice sheet: a continental glacier.

Source: University of Tokyo.

The Antarctic ice sheet: under-ice topography.

Source: University of Tokyo.

2 basic types of glaciers:

Continental glaciers (ice sheets)

Alpine glaciers

Cirque glaciers

Valley glaciers

Cirque glaciers feeding a valley glacier:

the Mer de Glace, French Alps.

Another valley glacier: Aletschgletscher, Swiss Alps.

Accumulation zone Equilibrium line

Ablation zone

COLDER

WARMER

Alpine glacier profile and mass

balance. Source: Christopherson, 2012, p. 495.

Firn/equilibrium line

Mer de Glace,

French Alps.

Global glacier retreat.

Source: Oerlemans.

Holgate Glacier, Alaska, 1909.

Source: National Snow and Ice Data Center glacier rephotography collection.

Holgate Glacier, Alaska, 2004.

Source: National Snow and Ice Data Center glacier rephotography collection.

McCall Glacier, Alaska, 1958.

Source: National Snow and Ice Data Center glacier rephotography collection.

McCall Glacier, Alaska, 2003.

Source: National Snow and Ice Data Center glacier rephotography collection.

Glacier movement processes. Source: Christopherson, 2012, p. 496.

Internal

flow in

glacier ice.

Crevasse patterns. Source; Clowes and Comfort, 1982.

The Western

Cwm, Khumbu

icefall and

Khumbu glacier,

Mount Everest (Source: Joe Simpson,

Dark Shadows Falling)

Everest

Khumbu

Icefall

Western

Cwm

Lhotse

Khumbu

Glacier

Cirque glaciers feeding a valley glacier:

the Mer de Glace, French Alps.

Crevasses on the Mer de Glace, French Alps.

Crevasses on an outlet

glacier of Vatnajökull,

Iceland.

GLACIAL EROSION PROCESSES

1. Plucking

2. Abrasion

Effects of glacial

plucking: formation

of a roche

moutonnee,

Lembert Dome,

Yosemite, CA.

Source: Christopherson,

2012, p. 503.

V-shaped

valley

Effects of alpine glaciation:

preglacial. Source: Christopherson, 2012, p. 498.

Effects of alpine glaciation:

glacial. Source: Christopherson, 2012, p. 498.

Horn Cirque

Arête

Truncated

spurs

Effects of alpine glaciation:

postglacial. Source: Christopherson, 2012, p. 498.

U-shaped valley

Cirques Horn Arête

Hanging valley

Hanging waterfall

Cwm Idwal, North Wales

(Source: Ogwen Valley Mountain Rescue)

Cwm Idwal, North Wales

(Source: Ogwen Valley Mountain Rescue)

Cirque- Helvellyn, Lake District, UK

Arete-

Striding Edge, Lake

District, UK

U-shaped valley (evidence of glacial erosion)

Hanging valley- Bridalveil Falls, Yosemite

Glacier retreat above Manang, Nepal

Lateral moraines

Terminal moraine

Pro-glacial lake

Glacial outwash: Kali Gandaki Valley, Nepal

Glacial outwash: Kali Gandaki Valley, Nepal

Glacial

depositional

features.

Source: Christopherson,

2012, p. 502.

North American ice cover, 18,000 BP. Source: Christopherson, 2012, p. 510.

North American ice cover, 9,000 BP. Source: Christopherson, 2012, p. 510.

Retreat of Laurentide ice sheet. Source: Christopherson, 2012, p. 511.

Retreat of Laurentide ice sheet. Source: Christopherson, 2012, p. 511.

Retreat of Laurentide ice sheet. Source: Christopherson, 2012, p. 511.

Retreat of Laurentide ice sheet. Source: Christopherson, 2012, p. 511.

Paleolakes in

the western US,

12-30,000 BP.

Source: Christopherson, 2012,

p. 512.

Lake Bonneville

Milankovitch cycles: cyclical wobbles in the

Earth’s orbit. Source: Houghton, 2009, p. 86; see Christopherson, 2012, p. 516-517.