The Barremian is an age in the geologic timescale (or a chronostratigraphic stage) between 129.4 ± 1.5 Ma (million years ago) and 125.0 ± 1.0 Ma). It is a subdivision of the Early Cretaceous Epoch (or Lower Cretaceous Series). It is preceded by the Hauterivian and followed by the Aptian Stage.[2]

Barremian
~129.4 – ~125.0 Ma
StratotypeBarremienA.JPG
Barremian sedimentary rock layers, France
Chronology
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 definitionNot formally defined
Lower boundary definition candidatesFAD of the Spitidiscus hugii-Spitidiscus vandeckii Ammonite group
Lower boundary GSSP candidate section(s)Río Argos, Caravaca de la Cruz, Murcia Province, Spain
Upper boundary definitionNot formally defined
Upper boundary definition candidates
Upper boundary GSSP candidate section(s)Gorgo a Cerbara, Piobbico, Central Apennines, Italy

Stratigraphic definitionsEdit

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 equivalentsEdit

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.[2]

SubdivisionEdit

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:

ReferencesEdit

NotesEdit

  1. ^ Super User. "ICS - Chart/Time Scale". www.stratigraphy.org. {{cite web}}: |last= has generic name (help)
  2. ^ a b See Gradstein et al. (2004) or the online geowhen database (link below)

LiteratureEdit

  • Cossmann, M. & Pelat, E. (1907): Le Barrémien supérieur à faciès Urgonien de Brouzet-lès-Alais (Gard). Mémoires de la Société Géologique de France, Paléontologie 15(37): 5-42. (in French)
  • Gradstein, F.M.; Ogg, J.G. & Smith, A.G.; (2004): A Geologic Time Scale 2004, Cambridge University Press.
  • Guzhikov, A.Yu. & Baraboshkin, E.J. (2006): Assessment of diachronism of biostratigraphic boundaries by magnetochronological calibration of zonal scales for the Lower Cretaceous of the Tethyan and Boreal belts. Doklady Earth Sciences 409(6): 843-846. doi:10.1134/S1028334X06060018

External linksEdit