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Unformatted text preview: crystallized at some depth below the surface (intrusive) their exposure at the surface implies the erosion of the rocks that overlay them at the time of crystallization coarser grain sizes e.g. syenite, granite, granodiorite, diorite, gabbro, peridotite, dunite Volcanic igneous rocks crystallized at or near the surface (extrusive) finely grained or glassy e.g. rhyolite, andesite, basalt Intrusive rock structures (pluton) Both the properties of the magma and the properties of the surrounding rocks (country rocks) play a role in determining the shape of intrusion formed. Concordant: approximately parallel to any structure (e.g. layering or folds) in the country rock e.g. sills, laccoliths, lopoliths, batholiths Discordant: cut across the structure of the country rock e.g. dykes...
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This note was uploaded on 09/26/2011 for the course CIVIL CIVL taught by Professor Wong during the Spring '11 term at HKU.
- Spring '11