Science Fair Project Encyclopedia
Tonalite
Tonalite is an igneous, plutonic (intrusive) rock, of felsic composition, with phaneritic texture. Mineral assembly is composed typically of plagioclase, more than 20% of quartz and rare alkali feldspar. Amphiboles and pyroxenes are common accessory minerals.
Trondhjemite is a variety of tonalite where biotite is the only mafic mineral.
See also: igneous rocks, list of rocks
10-26-2009 08:16:03
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The contents of this article is licensed from www.wikipedia.org under the GNU Free Documentation License. Click here to see the transparent copy and copyright details