A granitoide is a coagulation rock with a felsic ("acid") composition. Granitoide is a collective name for granite, kaliveldspat granite (sodium and / or potassium rich), granodiorite and tonalite (calcium rich).
Granitoide has a highly differentiated composition, which means that the magma far from the original source (the upper coat) has been developed for the solid. Often the composition is contaminated by the surrounding rock (the so-called S-type granitoid) or arises by mixing different magma's.
Granitoids often occur as intrusions during the last stages of orogenesis (the formation of a mountain), in the formation of intramontaneous cymbals (orogenic collapse stage). For example, in Europe, there are many granitoid batholites with ages in the Late Carboon or Early Perm, in the last stages of the Hercynic orogenesis. Examples can be found in the Armoric Massif and the Bohemian Massif. In the Alps there are also some Tertiary granitoid bodies, indicating that the mountain formation is in the final phase.
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