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Segments of rock (strata) in chronostratigraphy | Time spans in geochronology | Notes to geochronological units |
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4 total, half a billion years or more |
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10 defined, several hundred million years |
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22 defined, tens to ~one hundred million years |
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tens of millions of years |
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millions of years |
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subdivision of an age, not used by the ICS timescale |
A geologic age is a subdivision of geologic time that divides an epoch into smaller parts. A succession of rock strata laid down in a single age on the geologic timescale is a stage.
See also[edit]
References[edit]
- ^ Cohen, K.M.; Finney, S.; Gibbard, P.L. (2013), International Chronostratigraphic Chart (PDF), International Commission on Stratigraphy.