The Late Cryogenian Age of the Kumysty Granosyenite Complex, Greater Karatau, Southern Kazakhstan

Resumo

The results of geochronological U–Pb studies of quartz syenite of the Kumysty Сomplex of the Greater Karatau Ridge (Southern Kazakhstan) revealed its Late Neoproterozoic age of 717 ± 4 Ma. It is shown that the Kumysty Complex syenite along with the Kainar Formation, rhyolite and basalt are the youngest rocks composing the basement of the Precambrian Karatau–Dzhebagly massif: the formation was completed in the second half of the Cryogenian. The data on the ages of the youngest basement complexes of the Precambrian massifs in the western part of the Central Asian Belt indicate that the completion of magmatic activity within different massifs occurred diachronously during the Neoproterozoic.