Early Paleozoic granitoid associations of the Altai-Sayan folded area: Their types and importance in paleogeodynamic reconstructions

The structure, geochemical composition, and position of Early Paleozoic gra nitoid associations of the Altai-Sayan folded area are considered by the ex ample of four major granitoid groups (dated from C-1 to O-S): 1) early isla nd-arc plagiogranites (C-1) 2) basic granitoids of mature island arcs (C-3- O) 3) alkali granitoids of back-are continent-marginal zones (O-S-1), and 4 ) migmatite-granite complexes of shear crush zones (O-S). The geological, p etrological, and petrogeochemical features of the associations reflect the successive stages of accretion-collision evolution of Early Paleozoic ocean -continental zones.