Berriasian

System/
Period		 Series/
Epoch		 Stage/
Age		 Age (Ma)
Paleogene Paleocene Danian younger
Cretaceous Upper/
Late		 Maastrichtian 66.0–72.1
Campanian 72.1–83.6
Santonian 83.6–86.3
Coniacian 86.3–89.8
Turonian 89.8–93.9
Cenomanian 93.9–100.5
Lower/
Early		 Albian 100.5–~113.0
Aptian ~113.0–~125.0
Barremian ~125.0–~129.4
Hauterivian ~129.4–~132.9
Valanginian ~132.9–~139.8
Berriasian ~139.8–~145.0
Jurassic Upper/
Late		 Tithonian older
Subdivision of the Cretaceous system
according to the IUGS, as of July 2012.

In the geological timescale, the Berriasian is an age or stage of the Early Cretaceous. It is the oldest, or lowest, subdivision in the entire Cretaceous. It spanned the time between 145.0 ± 4.0 Ma and 139.8 ± 3.0 Ma (million years ago). The Berriasian succeeds the Tithonian (part of the Jurassic) and precedes the Valanginian.[1]

Stratigraphic definition

The Berriasian Stage was introduced in scientific literature by Henri Coquand in 1869. It is named after the village of Berrias in the Ardèche department of France. The largely non-marine English Purbeck Formation is in part of Berriasian age. In fact, the first rocks to be described of this age were the beds of the English Purbeck Formation, named as the Purbeckian by Alexandre Brongniart in 1829 following description by Henry De la Beche, William Buckland, Thomas Webster and William Henry Fitton.

The base of the Berriasian, which is also the base of the Cretaceous system, has traditionally been placed at the first appearance of fossils of the ammonite species Berriasella jacobi. But this is a species that has a stratigraphically problematic and geographically limited distribution. A global reference profile (a GSSP) for the Berriasian is under active consideration by the International Subcommission on Cretaceous Stratigraphy (ISCS) of IUGS. A range of contender GSSP localities currently being studied in detail by the ISCS's Berriasian Working Group include localities as far apart as Mexico, Ukraine, Tunisia, Iraq and the Russian Far East. Several markers are being employed to refine correlations and to work towards definition of a base for the Berriasian Stage. These include calcareous nannofossils, such as Nannoconus, calpionellids, ammonites, palynological data and magnetostratigraphy, notably magnetozone M19n. The calibration of these markers, especially Nannoconus steinmannii minor, N. kamptneri minor, and Calpionella alpina, within precisely fixed magnetozones gives greater precision in trying to identify the best position for a boundary.

In the Tethys Ocean, the Berriasian consists of four ammonite biozones, from top to bottom (latest to earliest):

The top of the Berriasian stage is defined by the base of the Valanginian, which is fixed at the first appearance of calpionellid species Calpionellites darderi. This is just a little below the first appearance of the ammonite species Thurmanniceras pertransiens.

Palaeontology

Birds (avian theropods)

Birds of the Berriasian
Taxa Presence Location Description Images

Crocodylomorphs (Non-Thalattosuchian)

Non-Thalattosuchian Crocodylomorphs of the Berriasian
Taxa Presence Location Description Images
Dakosaurus andiniensis
Geosaurus
Goniopholis
Steneosaurus

Mammalia

Mammals of the Berriasian
Taxa Presence Location Description Images
Durlston Bay, Dorset, England
Durlston Bay, Dorset, England; Spain
Portugal
Durlston Bay, Dorset, England
Portugal

†Ornithischians

Ornithischians of the Berriasian
Taxa Presence Location Description Images
Swanage, England A bipedal herbivore, it was around 0.6 meters (2 ft) long. Unlike most ornithischians, Echinodon had one or two caniniform teeth in each maxilla.
Echinodon
Hylaeosaurus
Owenodon
Valdosaurus
Kirkwood Formation, Cape Province, South Africa A 4 meters long, 1.8 meters high stegosaurid with a skull similar to Kentrosaurus
Isle of Wight, England; Niger, Africa A dryosaurid

†Pterosaurs

Pterosaurs of the Berriasian
Taxa Presence Location Description Images
Purbeck Limestone, Dorset, England

†Sauropods

Sauropods of the Berriasian
Taxa Presence Location Description Images
Pelorosaurus

†Thalattosuchia

†Thalattosuchians of the Berriasian
Taxa Presence Location Description Images
From Kimmeridgian to Valanginian Austria, England, Germany, Portugal and Switzerland
Attested since Toarcian England, France, Germany, Switzerland and Morocco

†Theropods (non-avian)

†Non-avian theropods of the Berriasian
Taxa Presence Location Description Images
Dromaeosauroides

References

Notes

  1. ↑ See Gradstein et al. (2004) for a detailed geological timescale
  2. 1 2 Only known from this stage.
  3. 1 2 3 4 5 6 7 8 9 Dating uncertain.

Literature

External links

Cretaceous Period
Lower/Early Cretaceous Upper/Late Cretaceous
Berriasian | Valanginian | Hauterivian
Barremian| Aptian | Albian		 Cenomanian | Turonian | Coniacian
Santonian |Campanian | Maastrichtian
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