2. Glaciers- Important in understanding global scale climate change
Related to all 5 of the Earth’s systems
Exosphere- changes in the amount of sunlight cause glaciations
Hydrosphere- glacial ice is frozen water, part of the hydrosphere
Geosphere- Glacial ice flows over and modifies land
Atmosphere- alteration of global atmospheric patterns contributes to glacial ice formation
Biosphere- ice displaces animals and plants

3. Importance • • Glacial times represent significant time
periods in Earth's history
periods in Earth's history
Proterozoic, Pennsylvanian, Pleistocene • •
Represent major climatic departures
Represent major climatic departures
from the modern on a Global Scale
from the modern on a Global Scale • •
Cyclic in Nature
Cyclic in Nature • •
Man's Influence???
Man's Influence??? • •
Glacial Ice contains records of
Glacial Ice contains records of past
atmospheric changes
atmospheric changes

4. Origin of ice

8. Response of a Glacier to Changes in Glacial Budget
If accumulation = ablation, then no advance or retreat, but continues to flow
If accumulation > ablation, then glacier advances while flowing
If accumulation < ablation, then glacier retreats, but continues to flow

12. Erosional Processes Erosional Processes ･ ･ Important erosional
processes associated
processes associated
with glaciers include
with glaciers include
plucking, abrasion, and
plucking, abrasion, and
bulldozing.
bulldozing. ･ ･
Plucking and abrasion
Plucking and abrasion
are most common
are most common
>
>
can form a landform
can form a landform
called a roche
called a roche
moutonnee
moutonnee

13. Erosional features
Roche Moutonnée

15. Erosional features Hanging Valley Horn Arete Cirque U-shaped trough
Col
Truncated Spurs

16. Glacial Deposits Glacial Deposits • • glacial drift- glacial drift-
A general term
A general term
refering to sediment formed by any
referring to sediment formed by
glacial action.
Any glacial action. • •
Till
Till
(Diamicton)
(Diamicton)
poorly sorted,
poorly sorted,
unlayered material directly
unlayered material directly
deposited by a glacier; ice contact
deposited by a glacier; • •
Stratified drift (Outwash)
Stratified drift (Outwash)
sorted,
sorted,
layered sediment usually
layered sediment usually
deposited by meltwater streams.
deposited by meltwater streams.
Proglacial or ice contact

17. A glacial erratic 6 ft Yellowstone Park
Depositional features- glacial erratic
A glacial erratic
6 ft
Yellowstone Park

18. Sediments-
Glacial Till exposed in Iowa

19. Depositional features- moraines
Moraine formation- made of Till, deposited by ice

20. Depositional features- moraines
Moraine formation- made of Till, deposited by ice

21. Depositional features- moraines
Moraine formation- made of Till, deposited by ice

22. ･ ･ Lateral Lateral moraines moraines Medial Medial moraines moraines
Lateral and Medial
Lateral and Medial
Moraines are sediment
Moraines are sediment
eroded from the valley
eroded from the valley
sides and deposited by
sides and deposited by
a glacier. They often
a glacier. They often
appear as dark stripes
appear as dark stripes
in a glacier.
in a glacier.

23. Depositional features- distribution of moraines

24. Depositional features- Kames, eskers, kettle lakes,
drumlins, outwash plain (sandur)

25. Depositional features- Kames, eskers, kettle lakes,
drumlins, outwash plain (sandur)

26. Outwash with kettles
moraine
Kame terrace
Outwash
Kettle lakes

27. Outwash Plain with eskers and a braided stream

28. Pleistocene Glaciation Pleistocene Glaciations• •
The Pleistocene "ice age" began
The Pleistocene "ice age" began
~1.96 million years ago
~1.96 million years ago • •
Several glacial and interglacial
Several glacial and interglacial
episodes.
Episodes have occurred.
>
>
Glacial
Glacial
- a period of ice advance, generally
- a period of ice advance, generally
interpreted as a globally cool period.
interpreted as a globally cool period.
>
>
Interglacial
Interglacial
- a period of ice retreat, generally
- a period of ice retreat, generally
interpreted as a globally warm period.
interpreted as a globally warm period.
We are in an interglacial period right now

29. Milankovich Orbital Theory Milankovitch Orbital Theory• •
Proposed to account for the cyclical
Proposed to account for the cyclical
nature of Glaciations.
nature of Glaciations. • •
Astronomer & Mathematician Milutin
Astronomer & Mathematician Milutin
Milankovich attributed the glaciation to
Milankovitch attributed the glaciation to
variation in three parameters of the
variation in three parameters of the
Earth's orbit.
Earth's orbit.

30. Obliquity- not shown
eccentricity
precession

31. warm
warm
cold
cold 1 3 4 5

32. Erie Lobe