Saturday, 26 February 2011

intrusive igneous rocks

intrusive means the rocks have been formed in the earth.

Minor intrustions - cool at the hypabyssal depth below the surface and includes sills and dykes

major intrusions - are plutonic and cool depth below the surface and include batholiths

chilled margins are where the ingneous rock has colled rapidly so have few chrystals, a baked margin is the country rock where it was heated by the intrustion and altered

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