Barremian

The Barremian was a time period in Earth's history between 125.77 million years ago and 121.4 ± 0.6 million years ago. It was part of the Early Cretaceous Epoch, which is also called the Lower Cretaceous Series. Before the Barremian came the Hauterivian stage, and after it came the Aptian stage. This time period is important for scientists who study the history of our planet and its rocks.

Stratigraphic definitions

The Barremian Stage was first described near the village of Barrême in Alpes-de-Haute-Provence, France, and was named by Henri Coquand in 1873.

Scientists decide when the Barremian began by looking for the first appearance of certain small sea creatures called ammonites, specifically Spitidiscus hugii and _Spitidiscus vandeckii](/w/5). They know when it ended by a change in Earth's magnetic field, which happens around the same time as another ammonite, Paradeshayesites oglanlensis, first appears.

Fossiliferous formations

Some important rock layers formed during the Barremian time hold many fossils. These include the Yixian Formation, La Huérguina Formation, Cedar Mountain Formation, Cloverly Formation, Elrhaz Formation, Jiufotang Formation, and Wessex Formation.

The Barremian is part of an older way to split the Cretaceous called the Gallic epoch, which is not used today. In some parts of Europe, it matches the early part of a stage called the Urgonian. In North America, it lines up with the later Coahulian and early Comanchean times. In New Zealand, it is inside the Mokoiwian, and in Japan, it matches the later Aritan time.

The Barremian is sometimes split into two smaller parts: early and late Barremian.

In a region called the Tethys domain, the Barremian has eleven zones based on a type of shell creature called ammonite:

• zone of Pseudocrioceras waagenoides
• zone of Colchidites sarasini
• zone of Imerites giraudi
• zone of Hemihoplites feraudianus
• zone of Gerhardtia sertousi
• zone of Ancyloceras vandenheckii
• zone of Coronites darsi
• zone of Kotetishvilia compressissima
• zone of Nicklesia pulchella
• zone of Nicklesia nicklesi
• zone of Spitidiscus hugii