Mossbauer spectra of white micas from the Central Western Carpathians Mountains

Potassium white micas from the rocks included into Cretaceous deformation zones (ca. 100-70 Ma in age) of the Central Western Carpathians were investigated by Mossbauer spectroscopy. White micas formed during a polystage evolution and changing P-T conditions of their crystallization in crustal-scale shear zones. We found criteria for distinguishing generations of celadonite-poor (muscovitic) and celadonite-rich (phengitic) white micas using Mossbauer spectroscopy. This method revealed contrasting spectra characterized by typical quadrupole doublets corresponding to Fe2+ and Fe3+ contents in white micas. They are in the range of 2.9-3.0 nun/s for phengite, and 2.6-2.7 mm/s for muscovite. Mossbauer spectra reflect well the chemical changes in white mica aggregates, especially of those close to the end-member muscovite and (alumino-)celadonite compositions.