GRANITIC PEGMATITES AS ESTIMATORS OF CRUSTAL PRESSURES - TEST IN THE EASTERN ADIRONDACKS, NEW-YORK

Liquidus equilibria of the granitic system (Q-Or-Ab-An-H2O) provide a potential means of estimating pressures and temperatures in natural rocks if certain requirements are met. These include limitations on bulk composition and mineralogy and a basis for a presumption of fluid-phase saturation of the former melt. A test of application of the experimental data is possible by means of at least two approaches. In this paper we show that an estimate of 7 kb obtained from a cross-cutting granite pegmatite in the eastern Adirondacks, New York, compares favorably with the results of other studies of similar granulite-facies metamorphism. © 1979 Geological Society of America.