Source of biotite in the Wuluma Pluton: Replacement of ferromagnesian phases and disaggregation of enclaves and schlieren

► Ferromagnesian minerals in the granite, and enclaves within it, are replaced by biotite. ► Different origins of schlieren in granite were determined. ► Most of the biotite in the Wuluma granite is not magmatic, but was derived from disaggregation of schlieren and enclaves. ► Replacement biotite and magmatic biotite re-equilibrates thus the composition of all biotite is essentially the same.