Segments of rock (strata) in chronostratigraphy | Time spans in geochronology | Notes to geochronological units |
---|---|---|
4 total, half a billion years or more | ||
14 total, several hundred million years | ||
12 total, tens to ~one hundred million years | ||
tens of millions of years | ||
millions of years | ||
subdivision of an age, not used by the ICS timescale |
References
- ^ Cohen, K.M.; Finney, S.; Gibbard, P.L. (2013), International Chronostratigraphic Chart (PDF), International Commission on Stratigraphy.