THE FIRST 40Ar/39Ar GEOCHRONOLOGICAL DATA FOR ORE METASOMATITES OF THE UNGLICHIKAN GOLD DEPOSIT, EASTERN PART OF THE MONGOL-OKHOTSK FOLD BELT

In our isotope-geochronological study, the age of ore metasomatites of the Unglichikan gold deposit is determined at 140–136 Ma. Magmatism of this age is absent in the study area, and it is thus unreasonable to relate the ore mineralization in the Unglichikan deposit to any magmatic process. We conclude that in the mobilization and redistribution of the ore material and the formation of the Unglichikan deposit, a significant role was played by dislocation processes accompanied by hydrothermal activity during the final stages of orogenesis in the Mongol-Okhotsk belt.

TECTONICS AND MAGMATISM

Tectonics and magmatism are inextricably interconnected phenomena of the single tectonic-magmatic process. Their scales must be a priori commensurate. However, in practice of geological work, small magmatic complexes often do not correspond to extended magma-controlling structures, due to the notorious complex creation that distorts the geological history, leads to genetic misconceptions and errors in forecasting and searching for mineralization. The urgency of the problem of correct identification of magmatic complexes is illustrated by examples on the materials of large tectonic structures of the Urals, Siberia and the Far East of Russia.