Mössbauer spectra of white micas from the Central Western Carpathians Mountains

Abstract

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 Mössbauer 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 Mössbauer spectroscopy. This method revealed contrasting spectra characterized by typical quadrupole doublets corresponding to Fe2+ Fe3+ contents in white micas. They are in the range of 2.9-3.0 mm/s for phengite, and 2.6-2.7 mm/s for muscovite. Mössbauer spectra reflect well the chemical changes in white mica aggregates, especially of those close to the end-member muscovite and (alumino-)celadonite compositions. © 2010 IOP Publishing Ltd.