Felsic:
A term used to describe an igneous rock that has a large percentage of light-colored minerals such as quartz, feldspar, and muscovite. Also used in reference to the magmas from which these rocks crystallize.
felsic -- Term used to describe the amount of light-colored feldspar and silica minerals in an igneous rock. Complement of mafic.
focus -- The initial point within the Earth that ruptures in an earthquake, directly below the epicenter.
Felsic magma contains relatively high quantities of sodium, aluminum, potassium, and silica. Its solidification produces granite, dacite, rhyolite, and granodiorite. Each of these rocks has a unique mineral composition and grain size.
It separates the deeper, mafic igneous rock of the Central Pacific Basin from the partially submerged continental areas of felsic igneous rock on its margins.
(see: planetary differentiation) It is thought that the core is largely composed of iron (80%), along with nickel and silicon; with other dense elements such as lead and uranium either being too rare to be significant or being felsic-seeking in ...
 See also: Surface, Area, Environment, Magma, Tectonic
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