Precambrian stratigraphic scale of the USSR

Abstract

A new stratigraphic scale of the USSR Precambrian officially adopted by the All-Union Precambrian Meeting in Ufa (1977) and approved by the National Stratigraphic Committee (1978) is discussed. Archean and Proterozoic were distinguished in the Precambrian, the boundary between being 2600 Ma [millions of yr B.P.]. Proterozoic is subdivided into the Lower- and Upper-Proterozoic with the boundary between them 1650 Ma. Riphean and Vendian are distinguished in the Upper Proterozoic. More detailed subdivisions of the Upper Proterozoic are Burzyanian, Yurmatian, Karatavian, Kudashian and Vendian. Lithological and paleontological characteristics [including biofacies] of these subdivisions and their radiometric age are given.