extrusive rock: Quick Facts

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Facts

Also Known As	volcanic rock • extrusive igneous rock

Photos

Tanna Island, Vanuatu: volcanic rock

Figure 25: Cross section of a convergent plate boundary involving a collision between two continental plates near a Himalaya-type mountain chain.

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Topics

pumice basalt perlite trachyte obsidian rhyolite phonolite diabase andesite pitchstone intrusive rock felsic and mafic rocks pegmatite spherulite micropegmatite colour index alkaline rock dike sill laccolith

Basalt sample returned by Apollo 15, from near a long sinous lunar valley called Hadley Rille. Measured at 3.3 years old.

(Bed) Rocks and (Flint) Stones