Silicic is an adjective to describemagma origneous rock rich insilica. The amount of silica that constitutes a silicic rock is usually defined as at least 63 percent.[1]Granite andrhyolite are the most common silicicrocks.
Silicic is the group of silicate magmas which will eventually crystallise a relatively small proportion of ferromagnesiansilicates, such asamphibole,pyroxene, andbiotite. The main constituents of a silicic rock will be minerals rich in silica-minerals, like silicicfeldspar or even free silica asquartz. These are just part of all the othersilicate minerals that make up 90% of the earth'scrust.
This broad classification is refined in practice based on more detained compositional studies where ever possible in the science ofmineralology.
The "Shammar group" is a silicic andvolcaniclastic sequence in northwesternSaudi Arabia.[2]
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