Retrograde Metamorphosis

Metamorphosis is not a one-way street, and it can go backwards, or retrograde, as readily as it goes prograde. We were once a garnet-mica schist, produced by deep heat and pressure upon a shale. But where this schist once had garnets are now lumps of nondescript mineral matter, although probably microscopic study of a thin section would show something there. The garnets were resorbed into the rest of the rock; it looks like the mica has been thoroughly recrystallized as well. The specimen comes from Adelaide, Australia, where intrusions of igneous rock probably did a number on the existing rocks like this mica schist. Igneous intrusions in ADELAIDE? You know i'm right...