Amphibole bearing parageneses from the western part of Mt. Psunj (Croatia) record evidence of prograding metamorphism. Optical and microprobe analyses, together with thermobarometric evaluations on amphibole bearing parageneses, show a zonation with Si- and Mg-concentrations decreasing from core to rim along with increasing Al-, Na-, and Ti-content. Changes in the chemical composition of amphibole grains are interpreted through coupled substitutions, and reactions with co-existing minerals during an increase in metamorphic conditions from greenschist to amphibolite facies. The change in P-T conditions recorded in the growth of amphibole grains (general prograding pattern) together with changes in the modal compositions in related parageneses could be interpreted in a model of a subduction zone
