The Role of Mineral Kinetics in the Development of Metamorphic Microtextures

Abstract

If the aim of a metamorphic petrologist is to reconstruct as fully as possible pressure—temperature—time (P—T—t) histories of suites of metamorphic rocks, then a consideration of more than the equilibrium aspects of the phase petrology is necessary. Mineral zonation and the preservation of relict minerals as inclusions in porphyroblasts are two expressions of disequilibrium that have been used to give at least qualitative indications of the evolution of pressure and temperature in a rock (e.g., Raheim and Green, 1974; Thompson et al., 1977; Holland and Richardson, 1979; Spear and Selverstone, 1983). Additional information about rock evolution is available from textures and microstructures, both reaction textures, and textures in the sense of the grain size, habit, or distribution of a newly grown mineral (Ehrlich et al., 1972; Kretz, 1966). The purpose of this paper is to discuss how the kinetic processes involved in metamorphic crystallization influence rock and mineral textures, and hence to suggest how rock textures may give information about P—T—t paths of metamorphism.KeywordsNucleation RateDehydration ReactionRegional MetamorphismInterfacial Free EnergyEquilibrium BoundaryThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.