Epidote dissolution–precipitation during viscous granular flow: a micro-chemical and isotope study

Abstract. Deformation of polymineralic aggregates can be accommodated by viscous granular flow, a process mediated the interplay among intracrystalline plasticity and dissolution–precipitation, each active in specific minerals under given P–T conditions. Some rock-forming like quartz feldspars have been intensively studied terms deformation processes. Instead, behavior epidote its role during flow is not well investigated, although this mineral ubiquitous granitic rocks deforming greenschist-facies In contribution, we provide microstructural geochemical evidence for occurrence dissolution–precipitation an epidote–quartz vein. The main part vein deformed, producing fold, which visible due to relicts primary-growth layering inside mechanisms include dynamic recrystallization subgrain rotation recrystallization, grain size reduction primary quartz. Recrystallization occurs contemporaneously with dissolution (re)precipitation boundary sliding, leading combined described as flow. combination sliding locally repeatedly produces creep cavities. These represent only loci nucleation new grains at expense dissolved ones, but they also allow fluid-mediated transport elements. same trace element patterns between old newly formed grains, much narrower variability latter, indicate chemical homogenization. nature fluid that mediates investigated using Pb–Sr isotope data epidote, suggest assisted internally recycled fluids addition syn-kinematic external component.