In the
geologic timescale
The geologic time scale or geological time scale (GTS) is a representation of time based on the rock record of Earth. It is a system of chronological dating that uses chronostratigraphy (the process of relating strata to time) and geochron ...
, the Valanginian is an
age or
stage of the
Early or Lower Cretaceous. It spans between 137.05 ± 0.2
Ma and 132.6 ± 0.2 Ma (million years ago). The Valanginian Stage succeeds the
Berriasian Stage of the Lower Cretaceous and precedes the
Hauterivian Stage of the Lower Cretaceous.
Stratigraphic definitions
The Valanginian was first described and named by
Édouard Desor in 1853. It is named after
Valangin
Valangin () is a former Municipalities of Switzerland, municipality in the district of Val-de-Ruz (district), Val-de-Ruz in the Cantons of Switzerland, canton of Neuchâtel (canton), Neuchâtel in Switzerland. On 1 January 2021 the former municip ...
, a small town north of
Neuchâtel in the
Jura Mountains
The Jura Mountains ( ) are a sub-alpine mountain range a short distance north of the Western Alps and mainly demarcate a long part of the French–Swiss border. While the Jura range proper (" folded Jura", ) is located in France and Switzerla ...
of
Switzerland
Switzerland, officially the Swiss Confederation, is a landlocked country located in west-central Europe. It is bordered by Italy to the south, France to the west, Germany to the north, and Austria and Liechtenstein to the east. Switzerland ...
.
The base of the Valanginian is at the first appearance of
calpionellid species ''
Calpionellites darderi'' in the stratigraphic column. A global reference section (a
GSSP
A Global Boundary Stratotype Section and Point (GSSP), sometimes referred to as a golden spike, is an internationally agreed upon reference point on a stratigraphic section which defines the lower boundary of a stage on the geologic time scale. ...
) had in 2009 not yet been appointed.
The top of the Valanginian (the base of the Hauterivian) is at the first appearance of the
ammonite
Ammonoids are extinct, (typically) coiled-shelled cephalopods comprising the subclass Ammonoidea. They are more closely related to living octopuses, squid, and cuttlefish (which comprise the clade Coleoidea) than they are to nautiluses (family N ...
genus
Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...
''
Acanthodiscus''.
Subdivision
The Valanginian is often subdivided in Lower and Upper substages. The Upper substage begins at the first appearance of ammonite species ''
Saynoceras verrucosum'' and the major
marine transgression Va3.
In the
Tethys domain, the Valanginian stage contains five ammonite
biozones:
* zone of ''
Criosarasinella furcillata''
* zone of ''
Neocomites peregrinus''
* zone of ''
Saynoceras verrucosum''
* zone of ''
Busnardoites campylotoxus''
* zone of ''
Tirnovella pertransiens ''
Flora
The oldest fossils that can definitely be attributed to the clade
Angiospermae (flowering plants) are dated to the Late Valanginian.
References
Notes
Literature
*; (2004): A Geologic Time Scale 2004,
Cambridge University Press
Cambridge University Press was the university press of the University of Cambridge. Granted a letters patent by King Henry VIII in 1534, it was the oldest university press in the world. Cambridge University Press merged with Cambridge Assessme ...
.
External links
GeoWhen Database - ValanginianMid-Cretaceous timescale
and ühttp://stratigraphy.science.purdue.edu/charts/Timeslices/5_JurCret.pdf 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
*02
Geological ages
Cretaceous geochronology
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