Abstract: The Sr isotope characteristic of carbonate rocks in the Central Azov Group has been reported (0.70322–0.70352), the Nd model age of silicate sediments has been calculated (2.34–2.31 Ga), and the U–Pb age of trondhjemites (2052 ± 5 Ma) breaking through carbonates was determined. According to the data obtained, the marine sedimentary cover of the Azov block making up the Early Precambrian Sarmatia Continent was formed in the Early Paleoproterozoic 2.23–2.34 Ga ago.