L.K. LEVSKY, E.S. BOGOMOLOV (IPGG RAS, VSEGEI), A.F. LOBIKOV, L.A. KOPYTCHENKO (IPGG RAS), A.V. TRAVIN (IGM SB RAS)

Isotope dating of the schist from the Northwest Ladoga area

U-­Pb, Sm-­Nd, Rb-­Sr and Ar/Ar isotopic geochronological methods were used for age determinations in rock-­formed minerals: garnets, staurolites, biotites and muscovites separated from the metamorphic schists of Northwest Ladoga area. Essential variations of measured dates for all isotopic systems and minerals from 1860 to 1625 Ma were caused by two reasons: the first is formation of metamorphic minerals and recrystalisation of primery formed minerals and the second is the secondary hydrothermal metasomatic processes.
Keywords: metamorphic schists, garnet, staurolite, biotite, muscovite, isotopic systems.