Protolith

Protolith refers to the precursor rock of a given lithology.

Granitoids can for instance be derived through melting of a sedimentary rock, and thus have a sedimentary protolith, or be derived from a magmatic precursor, and thus have a magmatic protolith.

Metamorphic rocks can be derived from any other rock and thus have a wide variety of protoliths.

Identifying a protolith is a prime aim of metamorphic geology and igneous geology.

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