GEOLOGICAL AGE OF THE FINAL MAGMATIC STAG E OF ELDJURTA GRANITE - RB-SR ISOCHRONOUS DATING OF APLITES

Rb-Sr isochrone corresponding to 2.12 +/- 0.10 m.y. with the initial S r isotopic ratio of 0.70690 +/- 7, MSWD=0.6. The isochrone is dating t he final magmatic stage in the history of the Eldjurta granite. The co rroboration of the previous isotopic geochronology data indicated in p articular that the more ancient age of ''Spider'' plagiogranites is di storbed by excess argon. The actual K-Ar age values older than 2 M.y. could not have been preserved within the thermal field in the vicinity of the Eldjurta granite massif.