A9R18EC.tmp 18 - Igneous rocks (1) Igneous rocks (2)...

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Prof. M. Fall - University of Ottawa 18 crust mantle Partial melting Magma chamber intrusive effusive Igneous rocks (1 J. Vail ancourt Like oils it in water, the magma has a density smaller than that of the mantle which surrounds it and it tends to move upward. In the earth’s crust the difference in density disapears, and thus the magma stop to move up and form a magma chamber. Generally, the magma will solidify in the chamber to form intrusive igneous rocks In some rare cases, various mechanisms increase the pressure in the tank that leads to volcanic eruption, i.e. overflowing of the magma on the earth surface to form effusive igneous rocks Effusive rocks or vulcanic rocks (from Vulcain, the got of the fire) Intrusive rocks or plutonic rocks (from Pluton, the got the hells) Jean Vail ancourt Igneous rocks (2) A) The extrusive igneous rocks b These rocks are formed by a fast cooling of the magma , when the magma reached surface. Thus, the crystals do not have time to develop and
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This note was uploaded on 03/21/2011 for the course GNG 4124 taught by Professor Soils during the Spring '11 term at Uni. of Nottingham Ningbo.

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