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A granitoid (a coarse grained igneous rock with <90% mafics, composed mostly of quartz, K-feldspar (alkali-feldspar) and plagioclase). It has 20-60% quartz and plagioclase is 65-90% of the total feldspar on the QAPF diagram. Coarse-grained plutonic rocks intermediate in composition between tonalite and granite containing quartz, plagioclase (oligoclase or andesine), and subordinate potassium feldspar, with biotite and/or hornblende, or, more rarely, pyroxene, as the mafic components; the approximate intrusive equivalent of rhyodacite.
Classification of GranodioriteHide
Sub-divisions of GranodioriteHide
Mineralogy of GranodioriteHide
Essential minerals - these are minerals that are required within the classification of this rock:
|Feldspar > Alkali Feldspar||Feldspar Group minerals rich in Potassium or Sodium.|
|Feldspar > Plagioclase||A petrological term for Albite-Anorthite Series.|
|Silica > Quartz||SiO2|
Non-essential minerals - these minerals are common, sometimes major components, but are not always present: