THERMOBAROMETRY AND P-T PATHS FROM GRANULITE FACIES ROCKS - AN INTRODUCTION

P-T paths from granulite terranes provide unique information about the thermal and tectonic evolution of the lower crust. Although methods for P-T path determination are well established, integration of the methods of thermobarometry, reaction path analysis, mineral zoning studies and diffusion studies with geochronologic analysis of temperature-time histories is necessary to further interpret observed assemblages and textures. Granulite P-T paths are characterized by either a phase of nearly isothermal decompression, which is likely related to a period of tectonic denudation, or nearly isobaric cooling, which may be related to the thermal relaxation of the crust following either the addition of heat by magmas or rapid denudation. Prograde portions of the P-T path are required to distinguish further between these options.