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 Age or AGE may refer to: Time and its effects * Age, the amount of time someone has been alive or something has existed ** East Asian age reckoning, an Asian system of marking age starting at 1 * Ageing or aging, the process of becoming older ...

stage Stage, stages, or staging may refer to: Arts and media Acting * Stage (theatre), a space for the performance of theatrical productions * Theatre, a branch of the performing arts, often referred to as "the stage" * ''The Stage'', a weekly Brit ...

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 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 143.1 ±0.6 Ma and 137.05 ± 0.2 (million years ago) ...

Stage of the Lower Cretaceous and precedes the

Hauterivian The Hauterivian is, in the geologic timescale, an age in the Early Cretaceous Epoch or a stage in the Lower Cretaceous Series. It spans the time between 132.6 ± 2 Ma and 125.77 (million years ago). The Hauterivian is preceded by the Valangi ...

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 Neuchâtel (, ; ; ) is a list of towns in Switzerland, town, a Municipalities of Switzerland, municipality, and the capital (political), capital of the cantons of Switzerland, Swiss canton of Neuchâtel (canton), Neuchâtel on Lake 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 ...

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 Calpionellids are an extinct group of eukaryotic single celled organisms of uncertain affinities. Their fossils are found in marine rocks of Upper Jurassic to Lower Cretaceous age. They were planktonic organisms with urn-shaped, calcitic t ...

species ''

Calpionellites darderi ''Calpionellites darderi'' is an extinct planktonic eukaryote and an important index fossil for the Lower Cretaceous stratigraphy. The first appearance of ''C. darderi'' marks the beginning of the Valanginian In the geologic timescale, the Va ...

'' 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 A marine transgression is a geologic event where sea level rises relative to the land and the shoreline moves toward higher ground, resulting in flooding. Transgressions can be caused by the land sinking or by the ocean basins filling with water ...

Va3. In the Tethys domain, the Valanginian stage contains five ammonite

biozone In biostratigraphy, biostratigraphic units or biozones are intervals of geological strata that are defined on the basis of their characteristic fossil taxon, taxa, as opposed to a Lithostratigraphy, lithostratigraphic unit which is defined by the ...

s: * 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 plants that bear flowers and fruits, and form the clade Angiospermae (). The term angiosperm is derived from the Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed within a fruit. The ...

(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 {{geochronology-stub