Intermediate composition

This article does not cite any sources . Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed.
Find sources: "Intermediate composition" – news · newspapers · books · scholar · JSTOR (October 2023) (Learn how and when to remove this message)

In igneous petrology, an intermediate composition refers to the chemical composition of a rock that has 51.5–63 wt% SiO₂ being an intermediate between felsic and mafic compositions. Typical intermediate rocks include andesite and trachyandesite among volcanic rocks and diorite and granodiorite among plutonic rocks.

v t e Common igneous rocks classified by silicon dioxide content
Type Ultramafic <45% SiO₂ Mafic 45–52% SiO₂ Intermediate 52–63% SiO₂ Intermediate–felsic 63–69% SiO₂ Felsic >69% SiO₂ Volcanic rocks: Subvolcanic rocks: Plutonic rocks: Picrite basalt Peridotite Basalt Diabase (Dolerite) Gabbro Andesite Microdiorite Diorite Dacite Microgranodiorite Granodiorite Rhyolite Microgranite Granite