BENDING THE CRUST!
Andes Mountains- formed on /near the boundary of 2 crustal plates(cp’s).
Summary of the process:
1. 2 cp’s colliding headon- the OP plate is subducted under
the CP (s. american plate)
a. creates the Peru-Chile trench
2. The Pacific plate is melted by the heat of the asthenosphere
(mantle)
3. Some of the material on the Pacific plate is scraped off by
te SA plate as it rides over it.
-This material is added to the base of the Andes.
4. At the same time we have columns of magma rising to the
surface
through crack/fissures (volcanic activity) to add material to
the Andes.
Andes: is being built up by 2 processes.
Himalayas- world’s youngest and largest mtns. Produced
by the collision of two Continental plates.
Summary:
1. India was once a separate continent-carried northward on the
Indian plate.
2. This plate collided with the continent of Asia (on the Eurasian
plate).
3. The collision forced the tip of the Indian continent under
the Asian continent.
-Thus forming these mountains.
Western Coastal Ranges, Alps, and Atlas Mtns have also been formed the collisions of crustal plates.
Aleutian Islands and Japan have been formed by another type
of meeting of crustal plates. Occur where the Pacific and the
Eurasian plates.
Summary:
1. Wstn edge of PP meets EP.
2. PP is subducted below the EP
3. This plate begins to melt, by high temp of asthenosphere (mantle)
4. This light, melted material is forced up as magma- forms strings
of volcanoes.
5. Because of the slow movement of these plates-the volcanoes
are formed underwater offshore.
6. Lava piles up until volcanoes rise above the water.
7. The volcanoes always form a curved shape= Island Arc.
8. Aleutian Islands and Japan are island arcs.
9. As the plates continue to move, the island arcs will be crushed
against the continents.
Trench may be formed when a OP is subducted beneath another
plate.
1. form deepest part of the oceans-6000 meters
2. Long and narrow depression
3. Most trenches are located near island arcs in the pacific ocean.