The Kokchetav microcontinent or the Kokchetav terrain distinguished by E.D. Shlygin [1] is a Precam-brian subplatform structure within the completed and uncompleted Caledonides. The Precambrian Kokchetav microcontinent is well distinguished in the geophysical fields, where the thickness of the Earth’s crust within the Continent ranges from 42 to 45 km [2], and the bounds of the microcontinent are traced by deep tectonic structures. Metamorphic rocks, developed within the microcontinent are divided into two series. The thickest lower (Zerendinskaya) series [3] consists mainly of metamorphic rocks of amphib-olite facies metamorphism. The upper (Sharykskaya) series is composed of Late Precambrian rocks metamorphosed under the green schist metamorphism. Both these series are separated by metamorphic and stratigraphic unconformity [3]. Precambrian rocks of both series were intruded by anomalously large masses of the Caledonian granitoids [4, 8]. The age of the rocks of the Kokchetav microcontinent remains a debatable topic. The analysis of the model age of the metaterrigenous rocks of the Zerendinskaya series (2.1–2.5 Ba) [4] and diamond-bearing gneisses of Kumdy-Kul (2.2–2.3 billion years) [5] allows us to conclude that the sedimentation of terrigenous material occurred as a result of the erosion of the Earth’s crust mainly in the Paleoproterozoic.

The Kokchetav subduction-collision zone (KSCZ) hosting ultrahigh- and high-pressure (UHP-HP) rocks underwent the multistage Vendian-Early Ordovician geodynamic evolution. The subduction of the Paleoasian oceanic lithosphere bearing blocks of continental crust and the collision of the Kokchetav microcontinent with the Vendian-Cambrian island-arc system ultimately led to the formation and exhumation of UHP-HP rocks. In the Vendian-Early Cambrian the margin of the Kokchetav microcontinent deeply subsided into the subduction zone (150–200 km), which led to UHP-HP metamorphism (the maximum at about 535 Ma) and to partial melting of its rocks. In next stage (535–528 Ma), the generated acidic melts including blocks of UHP-HP rocks quickly, at a rate of 1 m/year, ascended to depths of 90 km for 1 Myr. During subsequent 5 Myr, the UHP-HP rocks ascending at a rate of 0.6–1 cm/year reached the base of the accretionary prism (depths of 60–30 km). Then, in the period from 528 to 500 Ma, the UHP-HP rocks ascended along the faulting structures of the lower crust as a result of jamming the subduction zone by the Kokchetav microcontinent. During the period from 500 to 480 Ma, the UHP-HP rocks became part of the upper crust. This process led to the KSCZ, which comprises terranes of the Vendian-Early Arenigian subduction zone occurring at different depths, separated by zones of garnet-mica and mica schists, blastomylonites and mylonites. In the same period there was a jump of subduction zone, which led to the formation of the Ordovician Stepnyak island arc. As a result of the Late Arenigian-Early Caradocian microcontinent-island arc collisions (480–460 Ma), the KSCZ overrided upon the fore-arc trough of the Stepnyak island arc to form a thick accretion-collision orogen, which having experienced anatectic melting was intruded by collisional granites of the Zerenda complex 460–440 Ma in age.