| Four Ways to
"Make" a Mountain Mountainous
regions are created by movements of the earth's crust.
These movements occur very slowly, but on a large scale.
Different parts of the earth's crust react in different
ways to these movements, and form four basic types of
mountains.
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Volcanism Outpouring
lava and ash build a cone-shaped peak. The
Hawaiian Islands are volcanic mountains that have
"grown" out of the sea. The Cascades of
the Pacific Northwest are also volcanic in
origin.
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| Folding Pressures
from within the earth sometimes fold rock layers
into mountains and valleys. Ranges created in
this way often resemble huge washboards. The
Appalachians of the eastern United States were
created by the pressure of the Atlantic
Oceanplate "slamming" into the North
American plate.
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Faulting Movement
along breaks or faults between huge blocks of
rock makes mountains that may be quite high and
steep. The Himalaya
lie along the line where the Indian Subcontinent
meets the Eurasian landmass. The Sierra Nevada in
California were formed by movements of the
infamous San Andreas
fault line.
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| Doming The
core of a dome mountain was once magma, which
domed up the rocks above it into a sort of
blister. The Black Hills of South Dakota were
formed in this manner.
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Himalaya
San Andreas
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