Altai Mountains

The Altai Mountains span the region where Russia, Kazakhstan, China and Mongolia meet in Central Asia, holding Belukha Mountain, at about 4,506 meters the range's highest peak. Geologically the range is a much older structure than the Himalaya-adjacent ranges to its south: its rock originated as a Paleozoic accretionary orogen, built from volcanic island arcs, oceanic crust fragments and sedimentary material welded onto the growing Asian continent as part of the Central Asian Orogenic Belt, one of the largest accretionary mountain systems on Earth. That ancient structure went through a long period of relative quiet before being reactivated during the Cenozoic era, when far-field stresses transmitted north from the ongoing collision of the Indian and Eurasian plates, the same collision that raised the Himalaya and the Tian Shan, pushed the old Altai basement back upward along its existing faults. This two-stage history, ancient accretion followed by much later intraplate reactivation, distinguishes the Altai from the directly collision-built ranges further south. This entity documents the Altai Mountains specifically as a geological formation, a Paleozoic accretionary orogen of the Central Asian Orogenic Belt reactivated by Cenozoic far-field stress from the India-Eurasia collision.