Role of initial composition Obviously, the composition of the protolith plays a strong role in which minerals will grow. Thus basalts, granites and carbonate rocks each develope into the different metamorphic mineral assemblages leading ultimately to amphibolite, gneiss or marble respectively. Plate tectonic settings of metamorphism Hydrothermal metamorphism occurs near mid-ocean ridges driven by the heat of the volcanic activity there. Intrusion of igneous rocks drives contact metamorphism anywhere it occurs. Both of these sorts are metamorphism with high temperatures and low pressures.
Faults associated with plate boundaries create cataclastic metamorphismin the shallow crust.
When found on the surface, they are a strong indication that there once was a subduction zone in the neighborhood. Finally, burial of sediments in a sedimentary basin takes the rocks down the PT road characteristic of the crust, the so-called geotherm . They respond to this by developing the characteristic mineral phases of burial metamorphism. The minerals are a guide to just how deep and hot sediments got. For a summary of where melts form, see Figure 4.7 in your book.