There is no simple relationship between a PT point derived for a metamorphic complex from mineral assemblage and composition data and the equilibrium geotherm which may be calculated for the crust. Transient or complex geotherms of various slopes may be generated by magmatic intrusion, rapid burial, rapid uplift or tectonic thickening, or almost any combination of these processes. Proterozoic metamorphic complexes yield PT conditions ranging from about 6 kb, 600° in the Wakeham Bay area to 3-5 kb, 750° in the Bear Province and 10 kb, 980° in the Musgrave Ranges. The lowest apparent geotherms lie in linear metamorphic belts,...