Sapphirine Granulites
In this era of ultra-deep metamorphism, rocks from the lower crust may seem tame, but those at Wilson Lake, central Labrador, show signs of being very hot as well as deep. A study by Liu and Presnall (J. Petrology 2000) of the CMAS system at 20 kb suggests the possibility of igneous sapphirine (think spinel with a bit of silica in it!), and cites the Wilson Lake granulites as possible natural examples of such an occurrence, based on thin section study at UMass. But these rocks have NEVER BEEN PROBED, and they contain some beautiful assemblages as well as very unusual minerals (e.g. brown Fe‑sillimanite) and incipient melting assemblages. So this well‑mapped suite richly deserves detailed study, including probe analysis and melting studies, for a graduate thesis.