= Oligocene
{c}
The <Oligocene> is a geological epoch within the <Palaeogene>, between the <Eocene> and <Miocene>, approximately 34 to 23 million years before the present. It is also the corresponding interval of rock strata in chronostratigraphic classification.
The boundaries are defined using reference sections and correlation criteria, while their numerical ages are calibrated by dating and can be refined. A rock is therefore not assigned to an epoch solely because a rounded age estimate falls inside a convenient numerical interval. Fossils, stratigraphic relationships and independent dating must be interpreted together.<International Chronostratigraphic Chart by International Commission on Stratigraphy (2026-06)>[Cenozoic column, Palaeogene and Oligocene position]{ref}
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