MAJOR EPOCHS OF INTRUSIVE MAGMATISM OF KUZNETSK ALATAU, ALTAI, AND KALBA (from U-Pb isotope dates)

We present new U-Pb isotope dates for zircons from intrusive rocks of Kuznetsk Alatau, Gorny Altai, Rudny Altai, and Kalba and generalize the earlier published results of geochronological studies in these regions (U-Pb and Rb-Sr dates). Comparison of radiological ages with geological data permitted us to refine the scale of intrusive-magmatism events and recognize seven major epochs corresponding to a successive change of geodynamic settings: V-Є₁ – accretion-subductional, related to the evolution of sea-margin–island-arc systems of the Paleoasian ocean; Є₂-O₁ – accretion-collisional; $D1-D31$ and $D32-C1t$ – accretion-subductional, related to the evolution of active continental margin of the Andean type; C₁v-C₃ – accretion-collisional, related to the oblique collision of the Dzhungar microplate with the Siberian continent and closure of the Ob’-Zaisan paleoocean basin; P₁-T₂ – postcollisional, realized in the strike-slip motion regime; and T₃-J₁ – within-plate magmatism.