Microprobe analyses of phengite and biotite in granitic mylonites from the Simplon Shear Zone

This dataset presents in-situ microprobe analyses of phengite and biotite in metagranitic mylonites from the exhumed footwall of the Simplon Shear Zone, central Alps. The chemistry provided here was used together with careful microscopy to distinguish relict grains/zones from grains that were grown, recrystallized or otherwise re-equilibrated during deformation.