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The Tatshenshini area is dominated
by the St. Elias Mountains, the largest concentration
of high peaks in North America, including Mount
Fairweather, the highest peak in British Columbia
(4633 metres). Composed of sedimentary, metamorphic
and volcanic rocks, the St. Elias Mountains
have gone through several periods of major uplifting
ending about 10 million years ago, that produced
15 summits of more than 4000 metres. These peaks
are surrounded by massive ice fields which storms
blowing in from the Gulf of Alaska build up
with eternal ice and snow.
Rivers of ice flow down from
these ice fields to melt into frigid rivers
or to slide into coastal waters, reshaping the
landscape. It possesses the largest sub-polar
ice cap in the world, an estimated 31 surging
glaciers and 350 valley glaciers such as the
Walker Glacier where one can walk right onto
its toe. One of the wildest rivers in the world,
on its 300 kilometre journey to the Gulf of
Alaska, the Tat runs a ragged course through
a variety of terrains from dense forest to deep
canyons to broad glacially scoured valleys,
carving out the only corridor through the St.
Elias Mountains. It begins as a small river,
closely skirted by wooded slopes, then quickly
gains speed as it plummets down mountains and
swells as its tributaries join it. This region
has registered some of the most violent earthquakes
in North American history including the largest
which caused mountains to thrust up 50 feet
and surging glaciers to advance half a mile
in 5 minutes. More worrisome considering mining
industry's plans to proceed with a copper mine,
was the 1958 quake just 50 kilometres from Windy
Craggy Mountain which measured 7.9 on the Richter
scale and released rock slides, shattered glaciers,
split rivers and sank an island.
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The forests of the Tatshenshini-Alsek
region, influenced by their proximity to the
ocean, have an unusual diversity, from lush
coastal forests backing onto the interior mountain
domain of dry spruce and tundra, to the alders
and alpine meadows on the sweeping lower slopes
of the Alsek Range.
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