Barremian

{{Short description|Fourth age and stage of the Early/Lower Cretaceous}} {{Use dmy dates|date=June 2023}} {{Infobox geologic timespan | name = Barremian | color = Barremian | time_start = 125.77 | time_end = 121.4 | time_end_uncertainty = 0.6 | image_map = | caption_map = | image_outcrop = StratotypeBarremienA.JPG | caption_outcrop = Barremian sedimentary rock layers, France | image_art = | caption_art =  | timeline = Cretaceous | formerly_part_of = | partially_contained_in = | partially_contains =  | name_formality = Formal | name_accept_date = | alternate_spellings = | synonym1 = | synonym1_coined = | synonym2 = | synonym2_coined = | synonym3 = | synonym3_coined = | nicknames = | former_names = | proposed_names =  | celestial_body = earth | usage = Global (ICS) | timescales_used = ICS Time Scale | formerly_used_by = | not_used_by =  | chrono_unit = Age | strat_unit = Stage | proposed_by = | type_section = | timespan_formality = Formal | lower_boundary_def = Not formally defined | lower_def_candidates = FAD of the ''Spitidiscus hugii''-''Spitidiscus vandeckii'' Ammonite group | lower_gssp_candidates = Río Argos, Caravaca de la Cruz, Murcia Province, Spain | upper_boundary_def = Not formally defined | upper_def_candidates = * Base of magnetic polarity chronozone M0r. * Near FAD of the Ammonite ''Paradeshayesites oglanlensis'' | upper_gssp_candidates = Gorgo a Cerbara, Piobbico, Central Apennines, Italy  | o2 = | co2 = | temp = | sea_level = }}

The '''Barremian''' is an age in the geologic timescale (or a chronostratigraphic stage) between 125.77 Ma (million years ago) and 121.4 ± 0.6 Ma<ref>Cohen, K.M., Finney, S.C., Gibbard, P.L. & Fan, J.-X. (2023; updated) [https://stratigraphy.org/ICSchart/ChronostratChart2023-04.pdf The ICS International Chronostratigraphic Chart]. Episodes 36: 199-204.</ref> (Historically, this stage was placed at 129.4 million to approximately 125 million years ago<ref>{{cite web |date=March 2020 |title=ICS-Geological Timescale |url=https://stratigraphy.org/ICSchart/ChronostratChart2020-03.pdf |access-date=29 June 2023 |website=stratigraphy.or}}</ref>). 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.<ref name=geowhen>See Gradstein ''et al.'' (2004) or the online geowhen database (link below)</ref>

==Stratigraphic definitions== 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''.{{Citation needed|date=February 2024|reason=Citation needed for the entire above section, where none are provided}}

==Fossiliferous formations== Examples of geologic formations formed during the Barremian that preserve fossils are: Yixian Formation, La Huérguina Formation, Cedar Mountain Formation, Cloverly Formation, Elrhaz Formation, Jiufotang Formation, and Wessex Formation.

===Regional equivalents=== 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 {{ill|Urgonian|pl|Urgon}} 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.<ref name = geowhen />

=== Subdivision{{Citation needed|date=February 2024|reason=Citation needed for the entire above section, where none are provided}} === 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: * 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''

== References ==

===Notes=== {{reflist}}

===Literature=== * {{aut|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 lang|fr}} *{{aut|Gradstein, F.M.; Ogg, J.G. & Smith, A.G.}}; (2004): A Geologic Time Scale 2004, Cambridge University Press. * {{aut|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. <small>{{doi|10.1134/S1028334X06060018}}</small>

== External links == *[https://web.archive.org/web/20100822025941/http://www.stratigraphy.org/bak/geowhen/stages/Barremian.html GeoWhen Database - Barremian] *[http://stratigraphy.science.purdue.edu/charts/Timeslices/4_Mid-Cret.pdf Mid-Cretaceous timescale], at the website of the subcommission for stratigraphic information of the ICS *[https://web.archive.org/web/20060518101714/http://norges.uio.no/timescale/Fig18.1_Cret_colC.pdf Stratigraphic chart of the Lower Cretaceous], at the website of Norges Network of offshore records of geology and stratigraphy

Category:Barremian *04 Category:Geological ages Category:Cretaceous geochronology