The Aptian is an age 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 geoch ...

or a stage in the stratigraphic column. It is a subdivision of the Early or Lower Cretaceous Epoch or Series and encompasses the time from 121.4 ± 1.0 Ma to 113.0 ± 1.0 Ma (million years ago), approximately. The Aptian succeeds the

Barremian The Barremian is an age in the geologic timescale (or a chronostratigraphic stage) between 129.4 ± 1.5 Ma ( million years ago) and 121.4 ± 1.0 Ma). It is a subdivision of the Early Cretaceous Epoch (or Lower Cretaceous Series). It is pre ...

and precedes the

Albian The Albian is both an age of the geologic timescale and a stage in the stratigraphic column. It is the youngest or uppermost subdivision of the Early/Lower Cretaceous Epoch/ Series. Its approximate time range is 113.0 ± 1.0 Ma to 100.5 ± ...

, all part of the Lower/Early Cretaceous. The Aptian partly overlaps the upper part of the

Western European Western Europe is the western region of Europe. The region's countries and territories vary depending on context. The concept of "the West" appeared in Europe in juxtaposition to "the East" and originally applied to the ancient Mediterranean ...

Urgonian Stage. The Selli Event, also known as OAE1a, was one of two oceanic anoxic events in the

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of ...

Period, which occurred around 120 Ma and lasted approximately 1 to 1.3 million years. The Aptian extinction was a minor extinction event hypothesized to have occurred around 116 to 117 Ma.Archangelsky, Sergio.
The Ticó Flora (Patagonia) and the Aptian Extinction Event
" ''Acta Paleobotanica'' 41(2), 2001, pp. 115-22.

Stratigraphic definitions

The Aptian was named after the small city of

Apt Apt. is an abbreviation for apartment. Apt may also refer to: Places * Apt Cathedral, a former cathedral, and national monument of France, in the town of Apt in Provence * Apt, Vaucluse, a commune of the Vaucluse département of France * A ...

in the

Provence Provence (, , , , ; oc, Provença or ''Prouvènço'' , ) is a geographical region and historical province of southeastern France, which extends from the left bank of the lower Rhône to the west to the France–Italy border, Italian border ...

region of

France France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of overseas regions and territories in the Americas and the Atlantic, Pacific and Indian Oceans. Its metropolitan ar ...

, which is also known for its crystallized fruits. The original

type locality Type locality may refer to: * Type locality (biology) * Type locality (geology) See also * Local (disambiguation) * Locality (disambiguation) {{disambiguation ...

is in the vicinity of Apt. The Aptian was introduced in scientific literature by French palaeontologist

Alcide d'Orbigny Alcide Charles Victor Marie Dessalines d'Orbigny (6 September 1802 – 30 June 1857) was a French naturalist who made major contributions in many areas, including zoology (including malacology), palaeontology, geology, archaeology and anthrop ...

in 1840. The base of the Aptian Stage is laid at magnetic anomaly M0r. A global reference profile for the base (a

GSSP A Global Boundary Stratotype Section and Point (GSSP) is an internationally agreed upon reference point on a stratigraphic section which defines the lower boundary of a stage on the geologic time scale. The effort to define GSSPs is conducted ...

) had in 2009 not yet been appointed. The top of the Aptian (the base of the Albian) is at the first appearance of coccolithophore species ''Praediscosphaera columnata'' in the stratigraphic record.

Subdivision

In the Tethys domain, the Aptian contains eight

ammonite Ammonoids are a group of extinct marine mollusc animals in the subclass Ammonoidea of the class Cephalopoda. These molluscs, commonly referred to as ammonites, are more closely related to living coleoids (i.e., octopuses, squid and cuttle ...

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

s: * zone of ''Hypacanthoplites jacobi'' * zone of ''Nolaniceras nolani'' * zone of ''Parahoplites melchioris'' * zone of ''Epicheloniceras subnodosocostatum'' * zone of ''Duffrenoyia furcata'' * zone of ''Deshayesites deshayesi'' * zone of ''Deshayesites weissi'' * zone of ''Deshayesites oglanlensis'' Sometimes the Aptian is subdivided in three substages or subages: Bedoulian (early or lower), Gargasian (middle) and Clansayesian (late or upper). In modern formal chronostratigraphy the Aptian is divided into Lower and Upper sub-stages. The Lower Aptian is equivalent to the Bedoulian, and it includes the ''oglanensis'' to ''furcata'' Tethyan ammonite zones. The Upper Aptian is equivalent to the Gargasian and Clansayesian, it includes the ''subnodosocostatum'' to ''jacobi'' Tethyan ammonite zones (Gradstein et al. 2004).

Lithostratigraphic units

Examples of rock units formed during the Aptian are: Antlers Formation, Cedar Mountain Formation, Cloverly Formation, Elrhaz Formation,

Jiufotang Formation The Jiufotang Formation ( Chinese: 九佛堂组, pinyin: ''jiǔfótáng zǔ'') is an Early Cretaceous geological formation in Chaoyang, Liaoning which has yielded fossils of feathered dinosaurs, primitive birds, pterosaurs, and other organisms (see ...

Little Atherfield Little Atherfield is a small settlement on the Isle of Wight. It is near the coast in the Back of the Wight. The Isle of Wight is situated off the south coast of England. According to the Post Office the 2011 Census population of the village was ...

Mazong Shan The Mǎzōng Shān () is a minor mountain range of Subei Mongol Autonomous County, Jiuquan, northern Gansu, China, between the Altay range to the north and the Qilian range to the south. The Mǎzōng Shān peak rises to 2584 m. Climate Mount M ...

, Potomac Formation, Santana Formation, Twin Mountains Formation,

Xinminbao Group The Xīnmínbǎo Group () is a group of geological formations in north central China. They occur across a large depression between the Altai mountains of Mongolia to the north and the Qilian mountains of the Qinghai Plateau to the south, in the ...

and

Yixian Formation The Yixian Formation (; formerly transcribed as Yihsien Formation) is a geological formation in Jinzhou, Liaoning, People's Republic of China, that spans the late Barremian and early Aptian stages of the Early Cretaceous. It is known for its ...

References

Notes

Literature

*; 2004: ''A Geologic Time Scale 2004'',

Cambridge University Press Cambridge University Press is the university press of the University of Cambridge. Granted letters patent by Henry VIII of England, King Henry VIII in 1534, it is the oldest university press in the world. It is also the King's Printer. Cambr ...

. *; 1842: ''Paléontologie française: Terrains crétacés'', vol. ii.

External links

GeoWhen Database - AptianMid-Cretaceous timescale
at the website of the subcommission for stratigraphic information of the ICS *Stratigraphic charts of the Lower Cretaceous

an

at the website of Norges Network of offshore records of geology and stratigraphy {{Geological history, p, m Aptian, *05 Geological ages Cretaceous geochronology