Transcript Chapter 5 Deformation of the Crust

Chapter 5
Deformation of the Crust
Ch. 5.3
Mountain Formation
• Individual mountains are parts of mountain
ranges.
• Adjacent mountain ranges make up a
mountain system.
• The largest mountain systems are part of
two even larger systems called mountain
belts….the circum-Pacific belt, and the
Eurasian-Melanesian belt.
Plate Tectonics and Mountains
• Both mountain belts are along convergent
plate boundaries…believed to be
responsible for most mountain formation.
• Some mountain ranges may have formed
where now inactive plate boundaries may
have collided in the past…Appalachians.
Continental—Oceanic Collisions
• Subduction causes the continental crust to
be pushed up to form mountains.
• Melting rock creates magma which rises to
the surface, forming volcanoes.
• Example…The Cascade mountain range
in the Pacific Northwest.
Oceanic—Oceanic Collisions
• Subduction causes melting of rock.
Magma pushes up through the crust to
form underwater volcanoes.
• A volcanic island arc is the result. The
Mariana Islands in the North Pacific Ocean
are the peaks of volcanic mountains that
rose above sea level.
Continental—Continental Collisions
• No subduction. When continental crust
collides, it is pushed upward to form high
folded mountains.
• The rock layers are squeezed together like
an accordian.
• Example…the Himalayas.
Plateaus
• Large areas of flat-topped rock lifted high
above sea level. Found next to folded
mountains.
• The rock layers are pushed upward slowly
and gently enough that they remain flat
instead of deforming and folding into
mountains.