The granitoids of the Kalba–Narym batholith and the Irtysh shear zone (ISZ) are among the main geological features of the late Paleozoic Altai accretion–collision system (AACS) in Eastern Kazakhstan. Traditionally, it is believed that late Paleozoic strike-slip faults played a pivotal role at all stages of the development of the AACS, they were supposed to control deformation, magmatism, and ore deposits. This work is devoted to solving the problem of the tectonic evolution of the AACS based on the reconstruction of the thermal history of granitoids of the Kalba–Narym batholith in connection with the Chechek metamorphic dome structure, which is one of the highly metamorphosed blocks mapped within the ISZ. The new geological and geochronological data presented in this work allowed us to establish the sequence of formation of the Kalba–Narym granitoid batholith and link it with the evolution of the Irtysh shear zone (ISZ). It was revealed that in the late Carboniferous–early Permian (312–289 Ma), during the NE–SW compression, the Irtysh shear zone formed as a gently dipping thrust system into which gabbro of the Surov massif intruded. The combined manifestation of magmatic and tectonic processes caused the formation of tectonic mélange with cataclastic gabbro and metamorphic rocks of the Chechek metamorphic dome structure (312–289 Ma). Compression caused the formation of a cover-thrust structure. The thickening of the crust under the probable thermal action of the Tarim plume led to the formation of the early Permian Kalba–Narym batholith (297–284 Ma) within the Kalba–Narym terrane. Denudation of the orogen occurred before the Early Triassic (280–229 Ma). In this way the sequence of formation of the Kalba–Narym batholith and the ISZ is consistent with the concepts of the stages of plume-lithosphere interaction within the AACS under the influence of the late Carboniferous–early Permian Tarim igneous province, but in the cover-thrust tectonic setting.

The work is devoted to solving the problem of the tectonic evolution of the Late Paleozoic Altai accretion-collision system (AACS) on the basis of the reconstruction of the thermal history of the granitoids of the Kalba-Narym batholith in connection with the Chechek granite-gneiss structure. Traditionally, it is believed that Late Paleozoic strike-slips played an important role at all stages of the development of the AACS. They were supposed to control tectonic deformations, metamorphism, magmatism and metallogeny. Having collected the new geological and geochronological data, we have established the sequence of formation of the Kalba-Narym granitoid batholith and the Irtysh shear zone (ISZ), which are one of the main geological objects of the Altai accretion-collision system in Eastern Kazakhstan. It was revealed that in the Late Carboniferous–Early Permian (312–289 Ma), within the NE–SW compression, the Irtysh shear zone formed as a gentle thrust structure into which hot gabbroids of the Surov massif intruded. The combined overlaying of magmatic and tectonic processes caused the formation of tectonic melange with cataclastic gabbroids and metamorphic rocks of the Chechen granite-gneiss structure, framed by zones of green shales. Compression caused the formation of a cover-thrust structure. Melting of the thickened heated crust caused the formation of the Early Permian Kalba–Narym batholith (297–284 Ma) and subsequent denudation of the orogen to the Early Triassic (279–229 Ma). The sequence of formation of the Kalba-Narym granitoid batholith and the ISZ is consistent with the concepts of the stages of plume-lithospheric interaction within the AACS under the influence of the Late Carboniferous–Early Permian Tarim igneous province, but in the regime of cover-thrust tectonics.