Video Guide Continental Glaciation Night Of The Sun
M. Mustoe Geography
Abstract
What is wonderful about this film is its gentleness. It
has beautiful photography and very easy and mild music. What
is incredible about its content, however is the power of the geomorphological
mechanisms it is discussing, that is, massive amounts of ice and,
when this ice melts, the outflow water it produces. The video
shows the incredible impact of Continental Glaciation on the Midwestern
United States. These huge glaciers scoured the ground, leaving
all kinds of interesting landform signatures as far south as Nebraska.
Through periods of major changes in the atmosphere, continental
glaciers advanced south during four major advances. These were
named for the state they left their furthest influences in: The
Nebraskan, Kansan, Illinoian, and Wisconsin. The film is about
the Wisconsin period that began about 100 thousand years ago.
In the last 10,000 years and as far back as the Pleistocene Period
about 5 ice lobes evolved out of the Wisconsin Advance. An ice
sheet some 2 miles deep depressed the land with its weight and
scoured the surface as it slowly advanced. This activity produced
incredible amounts of deposition of rock flour in the Wisconsin
River (200 feet deep) and it generated a region which is known
today as the breadbasket of the United States because of the somewhat
rocky but nevertheless productive soils this activity produced.
Today (since 1971) the Ice Age Scientific Reserve is protecting
this amazing region created by the ice sheets.
This video talks about the following places or
regions:
Shiboigagin Marsh, Wisconsin
Nebraska, North Dakota
Kansas, Canada
Terms:
Sorting: boulders, rocks sand and silts....Finer materials pebble
Till:
Firn:
Drumlin, Drumlin Swarms steep up ice, taper gradually down ice
Kames
Moulin
Crevasse
Esker fast melting ice, speed
Kettle, Potholes
Moraine
Buttes
Ice Calving
Blue Ice Critical thickness, angle of repose