Priabonian

The Priabonian is, in the ICS's geologic timescale, the latest age or the upper stage of the Eocene epoch or series. It spans the time between 37.8 and 33.9 Ma. The Priabonian is preceded by the Bartonian and is followed by the Rupelian, the lowest stage of the Oligocene.

The Priabonian stage was introduced in scientific literature by Ernest Munier-Chalmas and Albert de Lapparent in 1893. The stage is named after the small hamlet of Priabona in the community of Monte di Malo, in the Veneto region of northern Italy.

The base of the Priabonian stage is at the first appearance of calcareous nannoplankton species Chiasmolithus oamaruensis (which forms the base of nannoplankton biozone NP18). An official GSSP had in 2009 not yet been assigned.

The top of the Priabonian stage (the base of the Rupelian stage and Oligocene series) is at the extinction of foram genus Hantkenina.

Sometimes local rock strata cannot be correlated in sufficient detail with the ICS timescale, and stratigraphers often use regional timescales as alternatives to the ICS timescale. The Priabonian overlaps for example the upper Johannian and lower Aldingan stages of the Australian timescale or the upper Nanzian and lower Refugian stages of the Californian timescale. Other regional stages which are more or less coeval with the Priabonian include the Jacksonian of the southeastern US and Runangan of New Zealand.

...
Wikipedia