- GeoRef, Copyright 2004, American Geological Institute. Reference includes data from Bibliography and Index of Geology Exclusive of North America, Geological Society of America, Boulder, CO, United States
"Granites of the main movement-phase of an orogenic zone form an integral part of the tectonic pattern being characteristically located at the intersection of cross- and main-folds. Here, an older granitic core pierces upwards through the anticlinal vault to form a diapir-fold in which migmatization, synchronous with movement, leads to the evolution of granodiorite. At higher structural levels where pressure is lower K-granites occur. Only at subvolcanic levels has evidence of melting been found. Recent hydrothermal investigations, by Bowen and Tuttle, show that synthetic haplo-pitchstones which begin to crystalize at minimum temperatures become richer in K as pressure decreases. These results are closely comparable with evidence provided by the sub-volcanic K-microgranites (migmatized Caledonian granodiorite) of Slieve Gullion, but have no applications to the granodiorites."