Plates:

- At a CONSTRUCTIVE plate boundary, two plates move apart. As the two plates move apart, magma rises up to fill up the gap. This causes volcanoes. however, since the magma can escape easily at the surface, the volcano does not erupt with much force. e.g. Mid Atlantic Ridge.

- At a DESTRUCTIVE plate boundary, the thicker, denser oceanic plate slides beneath the continental plate (subduction). The oceanic plate melts as it reaches the hot mantle. As the plates slide past each other, friction stores energy in rocks and the energy is released in earthquakes, magma may escape and cause volcanoes to occur. The folding of the continental plate forms mountains. e.g. the Nazca plate sub ducts underneath the South American plate.

- At a COLLISION plate boundary two plates of similar densities move together, i.e. a continental plate and a continental plate. This causes the material between them to buckle and rise up, forming fold mountains. e.g. The Himalayas formed by the African plate colliding with the Eurasian plate.

- At a CONSERVATIVE plate margin, the plates slide horizontally past each other and pressure builds up in the rocks on either side of the fault. The fault surface often rough the friction creates large strains along the faults. An earthquake happens when pressure built up and energy are released in a sudden, jerky movement. e.g the North American plate and Pacific plate.

	Created by chocoroco almost 11 years ago

Note on Geography, created by chocoroco on 29/05/2013.

Geography