Riphean (stage)
The Riphean is a stage or age of the geologic timescale from. The name Riphean is used in the Proterozoic stratigraphy of Russia and the Fennoscandian Shield in Finland. It was also used in a number of older international geologic timescales but, in the most recent timescales of the ICS, it is replaced by the Calymmian, Ectasian, Stenian, Tonian and Cryogenian periods of the Neoproterozoic and Mesoproterozoic eras.
The word 'Riphean' comes from the ancient Riphean Mountains, sometimes identified with the Ural Mountains.
The Riphean has been divided by geologists into the Early Riphean, Middle Riphean and Late Riphean subdivisions.
