Early Ordovician Age of Suprasubduction Ophiolites in the Northeastern Part of Central Kazakhstan: U–Th–Pb (SIMS) Dating of Plagiogranites

Suprasubduction zone ophiolites in the Bayanaul and Maikain–Kyzyltas zones in the northeastern part of Central Kazakhstan were studied. U–Pb dating of plagiogranites that constitute the plutonic complexes of the ophiolite sections was performed. The Early Ordovician age estimates of 480 ± 3 Ma for the plagiogranites in the Bayanaul zone and 477 ± 2 Ma in the Maikain-Kyzyltas zone were obtained for the first time. It was demonstrated that the formation time span of the plutonic and volcanosedimentary complexes in the studied ophiolites does not exceed 7–10 Ma.