Silicic

Silicic is an adjective to describe magma or igneous rock rich in silica. The amount of silica that constitutes a silicic rock is usually defined as at least 63 percent.[1] Granite and rhyolite are the most common silicic rocks.

Silicic is the group of silicate magmas which will eventually crystallise a relatively small proportion of ferromagnesian silicates, such as amphibole, pyroxene, and biotite. The main constituents of a silicic rock will be minerals rich in silica-minerals, like silicic Feldspar or even free silica as Quartz.

Example

The "Shammar group" is a silicic and volcaniclastic sequence in northwestern Saudi Arabia.[2]

gollark: I have no actual proof so much as a vague suspicion which I'm voicing semiironically.
gollark: hmm, what if jackgyver is SIMULTANEOUSLY an alt?
gollark: No, only me.
gollark: I have *tons* of old alts!
gollark: I made you do that to cast doubt on the idea of me being the astornomer, of course.

See also

References
  1. "USGS Volcano Hazards Program Glossary - Silicic". USGS. 2013-09-19. Retrieved 2016-01-02.
  2. Kellogg, Karl S. (1984), Reconnaissance geology of the Qufar Quadrangle, sheet 27/41 D, Kingdom of Saudi Arabia (PDF), Denver: United States Geological Survey, pp. 1–33, retrieved 2019-01-06


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