Barremian


The Barremian is an age in the geologic timescale between 129.4 ± 1.5 Ma. It is a subdivision of the Early Cretaceous epoch. It is preceded by the Hauterivian and followed by the Aptian stage.

Stratigraphic definitions

The original type locality for the Barremian stage is in the vicinity of the village of Barrême, Alpes-de-Haute-Provence, France. Henri Coquand defined the stage and named it in 1873.
The base of the Barremian is determined by the first appearance of the ammonites Spitidiscus hugii and Spitidiscus vandeckii. The end of the Barremian is determined by the geomagnetic reversal at the start of the M0r chronozone, which is biologically near the first appearance of the ammonite Paradeshayesites oglanlensis.

Regional equivalents

The Barremian falls in the Gallic epoch, a subdivision of the Cretaceous that is no longer used by the ICS. It overlaps the lower part of the Urgonian stage, which is sometimes used in western European stratigraphy. In North America, the late Coahulian and the early Comanchean correspond to the Barremian. In New Zealand, it falls within the Mokoiwian, and in Japan it corresponds to the late Aritan.

Subdivision

The Barremian is often subdivided into two substages or subages, Lower/Early and Upper/Late Barremian.
In the Tethys domain, the Barremian stage contains eleven ammonite biozones: