The Altaids, one of the largest and long-lived accretionary orogens in the world, developed
from ca. 600 Ma to 250 Ma by the multiple accretion of terranes of different origin in an evolving archipelago-type environment, which principally involved the growth and accretion of island arcs, the formation of active continental margin arcs, the incorporation of drifted microcontinents, ridge-trench interactions, the formation of back-arc basins, and arc-arc collisions. Post-collisional oroclinal bending and strike-slip faulting completed the tectonic development.
The Altaids began its development in Vendian (610–570 Ma) oceans between three approaching cratons, Siberia, Gondwana and Tarim-North China, where it continually evolved during the Early-Middle-Late Palaeozoic. During the Early Palaeozoic two continents, the peri-Siberian and Kazakhstan, formed mainly by the multiple accretions of microcontinents, island-arcs and oceanic islands. The peri-Siberian Continent formed around the microcontinents of Tuva-Mongolia and Altai-Mongolia through the multiple accretion of exotic, Izu-Bonin-type island arcs (e.g. Uimen-Lebed, Lake-Khamsara), and oceanic islands/seamounts/plateaus (e.g. Kurai, Dzhida, Bayanhongor), and to the formation of back-arc basins (i.e. Altai-Sayan, Barguzin). These multiple accretion-collision events led to the creation of several major peri-Siberian sutures by the end of the Early Palaeozoic (e.g. Bayanhongor, Dariv-Agardagh, Borus, Kurtushiba, Dzhida and Olkhon). The Mongol-Okhotsk Ocean opened within this newly accreted continent in the Early-Middle Palaeozoic. The Kazakhstan Continent formed mostly by the Early Silurian in Eastern Gondwana by the accretioncollision of several ribbon-microcontinents (e.g. Chatkal-Karatau, Chu-Yili, Aktau-Junggar) and island arcs (e.g. Boshchekul-Chingiz, Baidaulet-Akbastau). Kazakhstan was fi nally created by formation of the Kumdykol, Kyrgyz-Terskey, Dzhalair-Naiman sutures in the Arenigian (Lower Ordovician), and by formation of the Maikain-Kyzyltas, Yili-Erementau sutures in the Lower Silurian).
The tectonic evolution of the northern margin of Tarim-North China in the Early-Middle Palaeozoic mostly took place by island arc accretion (i.e. Tulinkai island-arc), active margin accretion (i.e. Bainaimiao arc and Ondor Sum wedge) and by the opening of back-arc basins, which led to separation of the Central Tianshan-Hanshan microcontinent.
From the mid-Paleozoic, the Siberian, Tarim-North China, and Kazakhstan continents began to mutually interact, leading to later oroclinal bending and large-scale rotation of the Kazakhstan continent during the Carboniferous, and to the main terminal sutures of the Altaids (i.e. South Tianshan, Turkestan, Uralian, Chara, Junggar-Balkash and Solonker) by the Permo-Triassic.