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granitoid
EntityQ1995951· pop 16· linked from 547 articles

thumb|Granite rock hand-sized sample

~3 min read

Encyclopedic overview

3 sections
Contents
  • Nomenclature and classification
  • Generalizations
  • References

thumb|Granite rock hand-sized sample

A granitoid is a broad term referring to a diverse group of coarse-grained igneous rocks that are widely distributed across the globe, covering a significant portion of the Earth's exposed surface and constituting a large part of the continental crust. These rocks are primarily composed of quartz, plagioclase, and alkali feldspar. Granitoids range from plagioclase-rich tonalites to alkali-rich syenites and from quartz-poor monzonites to quartz-rich quartzolites. As only two of the three defining mineral groups (quartz, plagioclase, and alkali feldspar) need to be present for the rock to be called a granitoid, foid-bearing rocks, which predominantly contain feldspars but no quartz, are also granitoids.

Excerpted from Wikipedia’s “granitoid” article, available under the CC BY-SA 4.0 licence.

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