Download Glaciers

And this is their story…..
“Fast Times at Glacial High”
ERIC MARCH
Glaciers
What is a glacier?
• A glacier is a massive, long-lasting,
moving mass of compacted snow and ice.
• Glaciers can only form on land, wherever
the amount of snow that falls in winter
exceeds the amount that melts in summer.
• There are two types of glaciers…
Alpine Glaciers
• Form on mountains because mountains usually
have deep winter snowfall and the summers are
short and cool.
• This type exists on every continent, EVEN on the
EQUATOR in Africa on Mount Kenya and in South
America on Mount Cayambe.
Mt. Kenya
Continental Glaciers
Miscellaneous Info
• Did you know that…
• Glaciers store about 75% of the world's freshwater.
• Glacierized areas cover more than 15,000,000 square
kilometers of the Earth.
• Glacier ice crystals can grow to be as large as baseballs.
• Glacial ice often appears blue because ice absorbs all
other colors except blue; which is reflected.
• Ice shelves may calve icebergs that are over 80
kilometers long.
• Almost 90% of an iceberg is below water--only about
10% shows above water.
• North America's longest glacier is the Bering Glacier in
Alaska, measuring 204 kilometers long.
Interesting Fact of the Day
• Byron Glacier
• Located in Alaska, On
Mt. Alyeska
• One hour south of
Anchorage
• Receding fairly quickly
due to global warming
• Tundra is slowly being
replaced by larger
plants.
Glacial Movement
• All glaciers can be
thought of as
rivers…just really big,
frozen rivers!
•Because all glaciers
are moving, most at
an average of 10
inches per day!
Glacial Movement
• Glaciers move two ways:
– Basal Slip
– Plastic Flow
Basal Slip
• The entire glacier slides over bedrock, much the
same way that a bar of soap slides down a board
Plastic Flow
• The glacier deforms like a fluid as it moves downhill
Plastic Flow
• The glacier deforms like a fluid as it moves
downhill
Glacial Movement
• Glaciers can move with both basal slip and
plastic flow
– Steep alpine glaciers will be mostly basal slip
– Shallow continental glaciers will be mostly
plastic flow
Features of Moving Glaciers
• Glaciers flowing over bumps in the bedrock
produce crevasses
Features of Moving Glaciers
Glacial Erosion
• Water freezes in gaps
in the bedrock,
freezes, and
dislodges boulders
that get swept up by
the glacier and
dragged along!