EPR CHARACTERISTICS OF FELDSPARS FROM GRANITES OF RUSKA POLYANA MASSIF OF KORSUN-NOVOMYRHOROD PLUTON (UKRAINIAN SHIELD)

Abstract

The electronic paramagnetic resonance spectra of microfractions of microcline, plagioclase and albite from the Ruska Polyana granites of the Korsun-Novomyrhorod pluton located in the Ukrainian Shield were measured. The results are used together with chemical and X-ray fluorescence analyzes to study the nature of Fe and Mn in the feldspars. It is shown that structural Fe3+ in the microcline and plagioclase reflect the iron content in the melt during crystallization of the granite. At the same time, nonstructural impurities of Fe3+ and Mn2+ in the feldspar monofractions, which are part of hydroxides and carbonates along grain boundaries, do not show correlations with structural impurities of Fe3+ replacing Al3+ ions in microcline and plagioclase, and presumably reflect postcrystallization processes. The ratio of the intensities of the Fe3+ EPR lines in the spectra of microcline indicates that its ordering temperatures are close to 670 K for all studied samples.