glaciers
DESCRIPTION
Glaciers. Formation. Snow accumulation More winter snowfall than summer melt Glacier formation is similar to sedimentary rock formation. Types of Glaciers. Valley glaciers or alpine glaciation Ice sheets or continental glaciation. Glaciers of the world. 85% of glacier ice in Antarctica - PowerPoint PPT PresentationTRANSCRIPT
GLACIERS
Formation Snow
accumulation More winter
snowfall than summer melt
Glacier formation is similar to sedimentary rock formation
Types of Glaciers Valley glaciers or alpine
glaciation Ice sheets or continental
glaciation
Glaciers of the world
85% of glacier ice in Antarctica 10% of glacier ice in Greenland Alpine glaciers comprise only 5%
of world’s glacier ice
Alpine Glaciers Form in valleys Gravity causes glacier movement Glaciers flow from higher to lower
elevation
Alpine Glacier Flow Velocity Overall downward flow velocity ranges from
a few millimeters to 15 meters per day Glaciers in warmer climate flow more
quickly Central part moves faster than sides Surface moves faster than base
Glacier movement Basal sliding Plastic flow Brittle/Rigid Zone
Continental Glaciers Cover a large part of a continent Gravity causes glacier movement Glaciers flow downward and outward
from a central high point Plastic flow more common than basal
sliding
Arctic Sea Ice Fresh water, like glaciers, but do not flow
like glaciers
And resulting landscapesGlacial Erosion
Erosion Glacier movement erodes the bedrock
underneath the glacier and can drastically change the landscape Plucking Abrasion Polishing Striations
Erratics &Striations
Alpine landscape features
Continental landscape features All the sediment that a glacier picks up is
deposited as unsorted and unlayered rock debris called “till”
Most features are created during glacial retreat
Effects on North AmericaIce Ages
Glacial Ages A period of long-term reduction in Earth’s
temperature, resulting in the presence of continental and polar ice sheets and alpine glaciers Glacial periods Interglacials
The last glacial period ended 10,000 years ago
Glacial Extent of Last Glacial Period ice_age.mov
Laurentide Ice Sheet
Stevens Point is located right beyond the recessional moraine—in outwash plain
Glacial Erosion in Wisconsin
Whitewater Wisconsin Map Activity
Topographic Maps
Topographic maps