Period of phlogopite mineralization formation in complexes of ancient metamorphic rocks

Particularities of the geological occurrence of phlogopite deposits of the Aldan, Yuzhno-Pamir and Near-Baikal provinces are briefly considered. Presented and discussed is the dating of phlogopites from the above deposits by the argon and the strontium methods. Strontium dating generally gives more ancient dates, than the argon method for the same specimens of phlogopite. The most likely explanation for this is the different loss of radiogenic isotopes of argon and strontium by phlogopites under the influence of superimposed processes. The maximum values of age given by the strontium method for the Aldan phlogopites are 2060 million years, for the Yuzhno-Pamir phlogopites, 1740 million years, and for the Near-Baikal phlogopites, 1000 million years. These data are indicative of a later phlogopite mineralization in the Near-Baikal region as compared to other discussed regions