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H33 Glaciers. Greenland
Position:
N60°
W40° approx.
Elevation:
view from 30000' / 9000m approx.
Image format:
35mm
GLACIERS. GREENLAND
GLACIERS are literally rivers of ice. Although solid to all intents
and purposes, glacial ice behaves like a very tough plastic when
subjected to great forces.
The story starts high up on the Greenland Ice Cap seen here from
above. Snow accumulates and becomes compressed by the weight of
new snow to form NÉVÉ (compressed snow) then FIRN (new ice). Gravity
induces a down hill motion of the ice. Ice moving via distinct
channels is called a GLACIER and these, like their faster flowing
RIVER counterparts ultimately reach the ocean. The rate of movement
may be measured in inches or centimeters per week or feet and
metres per day depending of temperature and gradient. 'Warm' glaciers
are well lubricated by melt water and move more quickly than 'cold'
glaciers.
Glaciers attract attention both for the features that exist on,
within and beneath them and for the features that they leave behind
following a "glacial retreat" (general thawing).
There are many features shown in this image, including:
CORRIE GLACIERS occupying dish-shaped hollows on the mountain
sides, and feeding the above the main glaciers.
AR TES - the knife-like ridges that are the WATERSHED divides
LATERAL MORAINES - accumulations of rock debris, which has fallen
off the rocky slopes above the glaciers.
MEDIAL MORAINES - where two lateral moraines merge at the CONFLUENCE
of two glaciers.
CREVASSES - pressure ridges and fissures in the glacier surface
caused by uneven flow over irregular terrain.
Less detail
Image Trail:
H4 Mountain stream on glaciated bed rock. Kerry, Ireland
L9 Grooved rock - glacial action. Kerry, Ireland
L17 Glacial lakes. Co. Kerry, Ireland
L16 Glacial lakes. Co. Kerry, Ireland
L18 Glacial erosion in mountain area. Co. Kerry, Ireland
L21 Grooved rock - glacial action. Acadia National Park. Maine, USA
L28 Granite dome and waterfall. Yosemite National Park. California,
USA
L50 Glaciated granite landscape. Yosemite National Park. California,
USA
H34 Glacier. Greenland
L79 Glacial Polish, Devil's Post Pile National Monument, California,
USA
L81 Glaciated mountains and corrie, Sierra Nevada, California, USA
L82 Corrie lakes, Snowdonia, Wales, UK
L83 ArÍte, Snowdonia, Wales, UK
Links:
http://www.galenfrysinger.com/glaciers_of_greenland.htm
http://www.galenfrysinger.com/greenland.htm
http://tqjunior.thinkquest.org/3876/glaciers.html
http://www.davison.k12.mi.us/bentley/glaciers.htm
http://www.glaciers.net/
http://nsidc.org/glaciers/information.html
http://vulcan.wr.usgs.gov/Glossary/Glaciers/description_glaciers.html
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