Basaltic Volcanism of Island-Arc–Back-Arc Basin System (Altai Active Margin)

Abstract: The results of prior studies are generalized and the author’s data on the geology, geochemistry, and isotope geochronology of the Early–Middle Devonian volcanic series of Western Gorny Altai and Rudny Altai that are related to two large volcanic systems, the Altai–Minusinsk and Altai–Salair, respectively, are presented. The studied basalts have convergent geochemical characteristics between the rocks in back-arc basins and island arcs or their rear extension zones. It is considered that the back-arc-basin–island-arc system was developed in the Early–Middle Devonian on the Altai margin of the Siberian continent.