Regional metamorphism takes place when rocks are buried deep in the crust. It is commonly associated with convergent plate boundaries and mountain range formation.
In other words regional metamorphism takes place over wide areas and results from both pressure and temperature generated at convergent plate margins during subduction and continental collision.
It results in deformation in non-hydrostatic and differential stress conditions and creates strongly foliated metamorphic rock (slates, schists, gneiss)
