Gamma-resonance spectroscopy of biotites of metamorphic rocks in Tatar arch Precambrian basement

A study was made by gamma-resonance spectroscopy of samples of biotites of metamorphic rocks of the pre-cambrian foundation of the Tatar arch, with a view to establishing a correlation between the thermobarometric conditions for the formation of biotites and the distribution of iron ions in their structure. The gamma-resonance spectra of the samples investigated were obtained on an electrodynamic spectrometer and were processed an a ''Nairi'' computer. It was established that gamma-resonance spectroscopy is an effective method for determining the degree of weathering of biotites by the way Fe3+ ions are distributed in non-equivalent positions of the octahedral layer of the biotites. This result may be of octahedral layer of the biotites. This result may be of considerable importance for the biotite determination of the radiological age of crystalline rocks. (V.V.)