I. A. Savinskiy, V. G. Vladimirov, V. P. Sukhorukov

The paper provides new data on metamorphism, age, and kinematics of deformations of the Chechek granite-gneiss structure (Chechek-Surovsky segment of the Irtysh shear zone). It is located in the central part of the shear zone in greenschist mylonites. The Chechek granite-gneiss structure has some diaper floating features, and it was controlled by both tectonic and rheological factors. Rheological factor was connected with melting of sedimentary rocks and rheomorphism of granitoid ones in the amphibolites facies environment. Syntectonic gabbroids of the Surovsky massif were a heat source of metamorphism. It was found that the age of 312 Ma is the upper boundary of accretion-collision events (transpression) occurred along the Irtysh suture when the Ob-Zaisan paleobasin was closed.

Key words: Irtysh, Chechek, shear zones, dome structure, metamorphism, geochronology.

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