Berriasian

In the geological timescale, the Berriasian is an age/stage of the Early/Lower Cretaceous. It is the oldest subdivision in the entire Cretaceous. It has been taken to span 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.

Berriasian
~145.0 – ~139.8 Ma
Chronology
Key events in the Cretaceous
-140 —
–
-130 —
–
-120 —
–
-110 —
–
-100 —
–
-90 —
–
-80 —
–
-70 —
–
An approximate timescale of key Cretaceous events.
Axis scale: millions of years ago.
Etymology
Name formalityFormal
Usage information
Celestial bodyEarth
Regional usageGlobal (ICS)
Time scale(s) usedICS Time Scale
Definition
Chronological unitAge
Stratigraphic unitStage
Time span formalityFormal
Lower boundary definitionUndefined
Lower boundary definition candidates
Lower boundary GSSP candidate section(s)None
Upper boundary definitionUndefined
Upper boundary definition candidatesFAD of the Calpionellid Calpionellites darderi
Upper boundary GSSP candidate section(s)

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 has been under active consideration by the International Subcommission on Cretaceous Stratigraphy (ISCS) of IUGS. A range of contender GSSP localities has been studied in detail by the ISCS's Berriasian Working Group including localities as far apart as Mexico, Ukraine, Tunisia, Iraq and the Russian Far East. Several markers have been employed to refine correlations and to work towards defining 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 give greater precision in trying to identify the best position for a boundary. In June 2016, the Berriasian Working Group voted to adopt Calpionella alpina as the primary marker for the base of the Berriasian Stage. In May 2019, a GSSP for the Berriasian was selected by a vote of the Berriasian WG of the ISCS: it is the profile of Tré Maroua in the Vocontian Basin (Hautes Alpes, France)

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

  • Thurmanniceras otopeta
  • Subthurmannia boissieri
  • Tirnovella occitanica
  • Berriasella jacobi/Pseudosubplanites grandis

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.

Regional terms used to refer to time periods equivalent to the Berriasian include the Ryazanian in Europe.

Palaeontology

Birds (avian theropods)
Birds of the Berriasian
Taxa Presence Location Description Images

Choristodera
Non-Thalattosuchian Crocodylomorphs of the Berriasian
Taxa Presence Location Description Images
Shokawa, Gifu Prefecture, Japan A choristoderan diapsid reptile closely resembling and closely related to the smaller choristoderan, Hyphalosaurus.
Shokawa

Crocodylomorphs (Non-Thalattosuchian)
Non-Thalattosuchian Crocodylomorphs of the Berriasian
Taxa Presence Location Description Images
England and Spain A species of goniopholidid mesoeucrocodylian. Was referred to as a species of Goniopholis by some authors.

Mammalia
Mammals of the Berriasian
Taxa Presence Location Description Images
Durlston Bay, Dorset, England
Lulworth Formation, 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
England A dryosaurid

†Pterosaurs
Pterosaurs of the Berriasian
Taxa Presence Location Description Images
Berriasian-Albian UK
Plataleorhynchus
Romania
Purbeck Limestone, Dorset, England

†Sauropods
Sauropods of the Berriasian
Taxa Presence Location Description Images
South Africa
Pelorosaurus

†Thalattosuchia
†Thalattosuchians of the Berriasian
Taxa Presence Location Description Images
From Kimmeridgian to Valanginian
Dakosaurus andiniensis
Geosaurus
From Tithonian to Valanginian
From Kimmeridgian to Hauterivian Austria, England, Germany, Portugal and Switzerland

†Theropods (non-avian)
†Non-avian theropods of the Berriasian
Taxa Presence Location Description Images
Dromaeosauroides

Berriasian-Barremian

Sao Khua Formation, Thailand

References

Notes
  1. Dating uncertain.
  2. Only known from this stage.

Literature
  • Gradstein, F.M.; Ogg, J.G. & Smith, A.G.; (2004): A Geologic Time Scale 2004, Cambridge University Press.
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