On the rate of kelyphitization of garnet: a constraint from compositional zoning of garnet

Abstract

Rate of kelyphitization of garnet was estimeted by applying a steady diffusion model accompanying a boundary migration and by the use of zoning width of the garnet adjacent to the kelyphite rim (for a Ronda garnet pyroxenite) and published diffuion data of garnet. The obtained rate is far greater than expected ascent rate of the peridotite body and therefore the termination of the kelyphitization cannot be ascribed to a cooling of the body but to a local stress development presumably occurred within the kelyphite rim due to the volume increase nature of the reaction.