Epoch (geology)

An epoch is a subdivision of the geologic timescale based on rock layering. In order (of increasing duration), the higher subdivisions are periods, eras and eons. We are currently living in the Holocene epoch (of the Quaternary period, of the Cenozoic era, of the Phanerozoic eon). The 3 epochs preceding the Holocene epoch are the Pleistocene epoch (10,000 to 2.5 million years ago), the Pliocene epoch (2.5 to 5.5 million years ago), and the Miocene epoch (5.5 to 23 million years ago).

Rock layers deposited during an epoch are called a series. Series are subdivisions of the stratigraphic column just like epochs are subdivisions of the geologic timescale.

References

• Gradstein, F.M.; Ogg, J.G. & Smith, A.G.; 2004: A Geologic Time Scale 2004, Cambridge University Press