Berriasian: Definition from Answers.com

System	Series	Stage	Age (Ma)
Paleogene	Paleocene	Danian	younger
Cretaceous	Upper	Maastrichtian	65.5–70.6
		Campanian	70.6–83.5
		Santonian	83.5–85.8
		Coniacian	85.8–89.3
		Turonian	89.3–93.5
		Cenomanian	93.5–99.6
	Lower	Albian	99.6–112.0
		Aptian	112.0–125.0
		Barremian	125.0–130.0
		Hauterivian	130.0–136.4
		Valanginian	136.4–140.2
		Berriasian	140.2–145.5
Jurassic	Upper	Tithonian	older
Subdivision of the Cretaceous system according to the IUGS, as of July 2009.

In the geologic timescale, the Berriasian is an age or stage of the Early or Lower Creteceous. It is the oldest or lowest subdivision in the entire Cretaceous. It spanned between 145.5 ± 4.0 Ma and 140.2 ± 3.0 Ma (million years ago). The Berriasian succeeds the Tithonian (part of the Jurassic) and precedes the Valanginian.^[1]

1 Stratigraphic definitions
2 Palaeontology
3 References

Stratigraphic definitions

The Berriasian stage was introduced in scientific literature by Henri Coquand in 1869. It is named after the village of Berrias in the Ardèche region of France. The English Wealden Group is of Berriasian age and in the past the name Wealden was also used to address rocks of the lowest Cretaceous.

The base of the Berriasian (also the base of the Cretaceous system) is at the first appearance of fossils of ammonite species Berriasella jacobi. A global reference profile (a GSSP) for the Berriasian had in 2009 not yet been established. A section in Austria has been proposed for ratification.

The top of the Berriasian stage (the base of the Valanginian) is at the first appearance of calpionellid species Calpionellites darderi in the stratigraphic column. This is just a little below the first appearance of ammonite species Thurmanniceras pertransiens.

In the Tethys domain, the Berriasian contains four ammonite biozones, from top to bottom:

Thurmanniceras otopeta
Subthurmannia boissieri
Subthurmannia occitanica
Berriasella jacobi

Palaeontology

Birds

Birds of the Berriasian
Taxa	Presence	Location	Description	Images
Eurolimnornis^[2]
Gallornis^[3]
Palaeocursornis^[2]
Wyleyia^[3]

Crocodylomorphs

Crocodylomorphs of the Berriasian
Taxa	Presence	Location	Description	Images
Dakosaurus andiniensis				Dakosaurus andiniensis Geosaurus Goniopholis
Geosaurus
Goniopholis
Lisboasaurus
Steneosaurus

Mammalia

Mammals of the Berriasian
Taxa	Presence	Location	Description	Images
Albionbaatar		Durlston Bay, Dorset, England
Bolodon		Durlston Bay, Dorset, England; Spain
Ecprepaulax		Portugal
Gerhardodon		Durlston Bay, Dorset, England
Iberodon		Portugal

Ornithischians

Ornithischians of the Berriasian
Taxa	Presence	Location	Description	Images
Echinodon^[3]		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.
Hylaeosaurus
Owenodon^[3]
Paranthodon		Kirkwood Formation, Cape Province, South Africa	A 4 meters long, 1.8 meters high stegosaurid with a skull similar to Kentrosaurus
Valdosaurus		Isle of Wight, England; Niger, Africa	A dryosaurid

Pterosaurs

Pterosaurs of the Berriasian
Taxa	Presence	Location	Description	Images
Plataleorhynchus

Sauropods

Sauropods of the Berriasian
Taxa	Presence	Location	Description	Images
Algoasaurus^[3]
Galveosaurus^[3]
Turiasaurus^[3]
Xenoposeidon^[3]
Pelorosaurus^[3]

Thalattosuchia

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

Theropods (non-avian)

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

References

Notes

^ See Gradstein et al. (2004) for a detailed geologic timescale
^ ^a ^b Only known from this stage.
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ Dating uncertain.

Literature

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

External links

GeoWhen Database - Berriasian
Jurassic-Cretaceous timescale, at the website of the subcommission for stratigraphic information of the ICS
Stratigraphic chart of the Lower Cretaceous, at the website of Norges Network of offshore records of geology and stratigraphy

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

This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)

Donate to Wikimedia

		Sci-Tech Dictionary. McGraw-Hill Dictionary of Scientific and Technical Terms. Copyright © 2003, 1994, 1989, 1984, 1978, 1976, 1974 by McGraw-Hill Companies, Inc. All rights reserved. Read more
		Wikipedia. This article is licensed under the Creative Commons Attribution/Share-Alike License. It uses material from the Wikipedia article "Berriasian". Read more

Berriasian

Contents