The set of metamorphic mineral assemblages (facies) in which basic rocks are represented by hornblende + plagioclase, the plagioclase being oligoclase-andesine or some more calcic variety. Epidote and almandine are common in amphibolites. The facies is typical of regional dynamothermal metamorphism under moderate to high pressures (in excess of 300 MPa) with temperatures in the range 450 to 700 degrees C.