Home – Home – Jornals – Russian Geology and Geophysics 2005 number 8

On the basis of the fundamental works of Academician Yu.A. Kuznetsov and later obtained research data, including ours, we have considered the geology, petrology, and petrochemistry of major types of Early Paleozoic granitoid associations of the Altai-Sayan area, as well as their role in the evolution of island-arc and collisional structures. Scarce early island-arc complexes are assigned to mantle tholeiitic plagiogranites. The superlarge areas of the mass occurrence of batholith granitoids formed at the accretion-collision stage have many geologo-lithologic peculiarities accounted for by their geodynamic settings. Study is given to early collisional K,Na-granitoid associations, Na-K-syenite-granite complexes of back-arc and continent-marginal zones, and Silurian collisional K-Na-granitoid complexes of the outer accretion zone, formed before magmatism took place on the Devonian active continental margin. The distribution of different types of associations is determined by the degree of maturity of the enclosing crust, which is expressed in the age and lateral compositional variations of granitoids. In general, the Early Paleozoic granitoid magmatism is specified by the existence of preceding basites of different types and repeated intense crushing of the enclosing rocks, which accompanied their metasomatism during the formation of granitoid plutons.