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 Ypresian is the oldest

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 ...

or lowest stratigraphic stage of the

Eocene The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...

. It spans the time between , is preceded by the

Thanetian The Thanetian is, in the International Commission on Stratigraphy, ICS Geologic timescale, the latest age (geology), age or uppermost stage (stratigraphy), stratigraphic stage of the Paleocene epoch (geology), Epoch or series (stratigraphy), Serie ...

Age (part of the

Paleocene The Paleocene ( ), or Palaeocene, is a geological epoch (geology), epoch that lasted from about 66 to 56 mya (unit), million years ago (mya). It is the first epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), ...

) and is followed by the Eocene

Lutetian The Lutetian is, in the geologic timescale, a stage (stratigraphy), stage or age (geology), age in the Eocene. It spans the time between . The Lutetian is preceded by the Ypresian and is followed by the Bartonian. Together with the Bartonian it ...

Age. The Ypresian is consistent with the Lower Eocene (Early Eocene).

Events

The Ypresian Age begins during the throes of the

Paleocene–Eocene Thermal Maximum The Paleocene–Eocene thermal maximum (PETM), alternatively ”Eocene thermal maximum 1 (ETM1)“ and formerly known as the "Initial Eocene" or “Late Paleocene thermal maximum", was a geologically brief time interval characterized by a ...

(PETM). The

Fur Formation The Fur Formation is a marine geological formation of Ypresian ( Lower Eocene Epoch, c. 56.0-54.5 Ma) age which crops out in the Limfjord region of northern Denmark from Silstrup via Mors and Fur to Ertebølle, and can be seen in many cliffs and ...

Denmark Denmark is a Nordic countries, Nordic country in Northern Europe. It is the metropole and most populous constituent of the Kingdom of Denmark,, . also known as the Danish Realm, a constitutionally unitary state that includes the Autonomous a ...

, the Messel shales in

Germany Germany, officially the Federal Republic of Germany, is a country in Central Europe. It lies between the Baltic Sea and the North Sea to the north and the Alps to the south. Its sixteen States of Germany, constituent states have a total popu ...

, the

Oise amber Oise amber () is a type of amber found near the Oise river near Creil in northern France. Oise amber is around 53 million years old, dating to the Early Eocene (Ypresian). Oise amber is softer than Baltic amber, although Oise amber is older ...

of France and Cambay amber of India are of this age. The Eocene Okanagan Highlands are an uplands subtropical to temperate series of lakes from the Ypresian. The Ypresian is additionally marked by another warming event called the Early Eocene Climatic Optimum (EECO). The EECO is the longest sustained warming event in the Cenozoic record, lasting about 2–3 million years between 53 and 50 Ma. The interval is characterized by low

oxygen-18 Oxygen-18 (, Ω) is a natural, stable isotope of oxygen and one of the environmental isotopes. is an important precursor for the production of fluorodeoxyglucose (FDG) used in positron emission tomography (PET). Generally, in the radiopharm ...

isotopes, high levels of atmospheric p, and low meridional thermal gradients.

Biodiversity Biodiversity is the variability of life, life on Earth. It can be measured on various levels. There is for example genetic variability, species diversity, ecosystem diversity and Phylogenetics, phylogenetic diversity. Diversity is not distribut ...

has been reported to have been significantly impacted by the conditions prevalent during the EECO. For instance, there were biotic turnovers among marine producers such as

calcareous nannofossils Calcareous nannofossils are a class of tiny (less than 30 microns in diameter) microfossils that are similar to coccoliths deposited by the modern-day coccolithophores. The nannofossils are a convenient source of geochronological data due to ...

among others etc.

Stratigraphic definition

The Ypresian Stage was introduced in scientific literature by Belgian geologist

André Hubert Dumont André — sometimes transliterated as Andre — is the French and Portuguese form of the name Andrew and is now also used in the English-speaking world. It used in France, Quebec, Canada and other French-speaking countries, as well in Portugal ...

in 1850. The Ypresian is named after the

Flemish Flemish may refer to: * Flemish, adjective for Flanders, Belgium * Flemish region, one of the three regions of Belgium *Flemish Community, one of the three constitutionally defined language communities of Belgium * Flemish dialects, a Dutch dialec ...

city of

Ypres Ypres ( ; ; ; ; ) is a Belgian city and municipality in the province of West Flanders. Though the Dutch name is the official one, the city's French name is most commonly used in English. The municipality comprises the city of Ypres/Ieper ...

in Belgium (spelled ''Ieper'' in Dutch). The definitions of the original stage were totally different from the modern ones. The Ypresian shares its name with the Belgian Ieper Group (French: ''Groupe d'Ypres''), which has an Ypresian age. The base of the Ypresian Stage is defined at a strong negative anomaly in δ¹³C values at the PETM. The official reference profile (

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. ...

) for the base of the Ypresian is the Dababiya profile near the

Egypt Egypt ( , ), officially the Arab Republic of Egypt, is a country spanning the Northeast Africa, northeast corner of Africa and Western Asia, southwest corner of Asia via the Sinai Peninsula. It is bordered by the Mediterranean Sea to northe ...

ian city of

Luxor Luxor is a city in Upper Egypt. Luxor had a population of 263,109 in 2020, with an area of approximately and is the capital of the Luxor Governorate. It is among the List of oldest continuously inhabited cities, oldest continuously inhabited c ...

.The GSSP was established by Dupuis ''et al.'' (2003) Its original

type section In geology, a stratotype or type section is the physical location or outcrop of a particular reference exposure of a stratigraphic sequence or stratigraphic boundary. If the stratigraphic unit is layered, it is called a stratotype, whereas the ...

was located in the vicinity of Ieper. The top of the Ypresian (the base of the Lutetian) is identified by the first appearance of the

foraminifera Foraminifera ( ; Latin for "hole bearers"; informally called "forams") are unicellular organism, single-celled organisms, members of a phylum or class (biology), class of Rhizarian protists characterized by streaming granular Ectoplasm (cell bio ...

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 ...

'' Hantkenina'' in the fossil record. The Ypresian Stage overlaps the upper Neustrian and most of the Grauvian

European Land Mammal Mega Zone The European Land Mammal Mega Zones (abbreviation: ELMMZ, more commonly known as European land mammal ages or ELMA) are zones in rock layers that have a specific assemblage of fossils ( biozones) based on occurrences of fossil assemblages of Europ ...

s (it spans the Mammal Paleogene zones 7 through 10.), the

Wasatchian The Wasatchian North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology (NALMA), typically set from 55,400,000 to 50,300,000 years Before Present, BP lasting . I ...

and lower and middle

Bridgerian The Bridgerian North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology (NALMA), typically set from 50,300,000 to 46,200,000 years BP lasting . It is usually c ...

North American Land Mammal Ages The North American land mammal ages (NALMA) establishes a geologic timescale for North American fauna beginning during the Late Cretaceous and continuing through to the present. These periods are referred to as ages or intervals (or stages when ref ...

, the

Casamayoran The Casamayoran () age is a period of geologic time (50.0–48.0 Ma) within the Early Eocene epoch of the Paleogene, used more specifically within the South American land mammal age (SALMA) classification. It follows the Itaboraian and precedes th ...

South American Land Mammal Age The South American land mammal ages (SALMA) establish a geologic timescale for prehistoric South American fauna beginning 64.5 Ma during the Paleocene and continuing through to the Late Pleistocene (0.011 Ma). These periods are referred to as age ...

and the Bumbanian and most of the Arshantan Asian Land Mammal Ages. It is also coeval with the upper Wangerripian and lowest Johannian regional stages of

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

and the Bulitian, Penutian, and Ulatisian regional stages of

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

References

Literature

* Dumont, A. H.; 1850: ''Rapport sur la carte géologique du Royaume'', Bulletins de l’Académie Royale des Sciences, des Lettres et des Beaux-Arts de Belgique 16 (2), pp. 351–373. *Dupuis, C.; Aubry, M.; Steurbaut, É; Berggren, W. A.; Ouda, K.; Magioncalda, R.; Cramer, B. S.; Kent, D. V.; Speijer, R. P. & Heilmann-Clausen, C.; 2003: ''The Dababiya Quarry Section: Lithostratigraphy, clay mineralogy, geochemistry and paleontology'', Micropaleontology 49 (1), pp. 41–59, . *Gradstein, F. M.; Ogg, J. G. & Smith, A. G.; 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 ...

. *Steurbaut, É.; 2006
''Ypresian''
, Geologica Belgica 9 (1–2), pp. 73–93.

External links

Paleogene timescale
at the website of the subcommission for stratigraphic information of the ICS
Stratigraphic chart of the Paleogene
at the website of Norges Network of offshore records of geology and stratigraphy {{Geological history, p, c Eocene geochronology Geological ages