The Danian is the oldest age or lowermost stage of the Paleocene

Paleocene

The Paleocene or Palaeocene, the "early recent", is a geologic epoch that lasted from about . It is the first epoch of the Palaeogene Period in the modern Cenozoic Era...

 epoch

Epoch (geology)

An epoch is a subdivision of the geologic timescale based on rock layering. In order, the higher subdivisions are periods, eras and eons. We are currently living in the Holocene epoch...

 or series

Series (stratigraphy)

Series are subdivisions of rock layers made based on the age of the rock and corresponding to the dating system unit called an epoch, both being formally defined international conventions of the geological timescale. A series is therefore a sequence of rock depositions defining a...

, the Paleogene

Paleogene

The Paleogene is a geologic period and system that began 65.5 ± 0.3 and ended 23.03 ± 0.05 million years ago and comprises the first part of the Cenozoic Era...

 period or system and the Cenozoic

Cenozoic

The Cenozoic era is the current and most recent of the three Phanerozoic geological eras and covers the period from 65.5 mya to the present. The era began in the wake of the Cretaceous–Tertiary extinction event at the end of the Cretaceous that saw the demise of the last non-avian dinosaurs and...

 era

Era

An era is a commonly used word for long period of time. When used in science, for example geology, eras denote clearly defined periods of time of arbitrary but well defined length, such as for example the Mesozoic era from 252 Ma–66 Ma, delimited by a start event and an end event. When used in...

 or erathem

Erathem

In stratigraphy, paleontology, geology, and geobiology an erathem is the total stratigraphic record deposited during a certain corresponding span of time, an era in the geologic timescale....

. The beginning of the Danian age (and the end of the precessing Maastrichtian

Maastrichtian

The Maastrichtian is, in the ICS' geologic timescale, the latest age or upper stage of the Late Cretaceous epoch or Upper Cretaceous series, the Cretaceous period or system, and of the Mesozoic era or erathem. It spanned from 70.6 ± 0.6 Ma to 65.5 ± 0.3 Ma...

 age) is at the Cretaceous-Tertiary extinction event

Cretaceous-Tertiary extinction event

The Cretaceous–Paleogene extinction event, formerly named and still commonly referred to as the Cretaceous-Tertiary extinction event, occurred approximately 65.5 million years ago at the end of the Maastrichtian age of the Cretaceous period. It was a large-scale mass extinction of animal and plant...

 . The age ended , being followed by the Selandian

Selandian

The Selandian is in the geologic timescale an age or stage in the Paleocene. It spans the time between and . It is preceded by the Danian and followed by the Thanetian. Sometimes the Paleocene is subdivided in subepochs, in which the Selandian forms the "Middle Paleocene".-Stratigraphic...

 age.

Stratigraphic definitions

The Danian was introduced in scientific literature by German

Germany

Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

-Swiss

Switzerland

Switzerland name of one of the Swiss cantons. ; ; ; or ), in its full name the Swiss Confederation , is a federal republic consisting of 26 cantons, with Bern as the seat of the federal authorities. The country is situated in Western Europe,Or Central Europe depending on the definition....

 geologist Pierre Jean Édouard Desor

Pierre Jean Édouard Desor

Pierre Jean Édouard Desor was a Swiss geologist. He associated in his early years with Louis Agassiz, studying palaeontology and glacial phenomena, and together with James David Forbes ascended the Jungfrau in 1841...

 in 1847. It is named after the Latin

Latin

Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...

 name for Denmark

Denmark

Denmark is a Scandinavian country in Northern Europe. The countries of Denmark and Greenland, as well as the Faroe Islands, constitute the Kingdom of Denmark . It is the southernmost of the Nordic countries, southwest of Sweden and south of Norway, and bordered to the south by Germany. Denmark...

. The Montian stage from Belgian

Belgium

Belgium , officially the Kingdom of Belgium, is a federal state in Western Europe. It is a founding member of the European Union and hosts the EU's headquarters, and those of several other major international organisations such as NATO.Belgium is also a member of, or affiliated to, many...

 stratigraphy (named after the city of Mons

Mons

Mons is a Walloon city and municipality located in the Belgian province of Hainaut, of which it is the capital. The Mons municipality includes the old communes of Cuesmes, Flénu, Ghlin, Hyon, Nimy, Obourg, Baudour , Jemappes, Ciply, Harmignies, Harveng, Havré, Maisières, Mesvin, Nouvelles,...

) is now considered a junior synonym and is no longer in use.

The base of the Danian is defined at the iridium

Iridium

Iridium is the chemical element with atomic number 77, and is represented by the symbol Ir. A very hard, brittle, silvery-white transition metal of the platinum family, iridium is the second-densest element and is the most corrosion-resistant metal, even at temperatures as high as 2000 °C...

 anomaly which characterized the Cretaceous

Cretaceous

The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...

-Paleogene boundary in stratigraphic sections worldwide. A section in El Kef

El Kef

El Kef , also known as Le Kef, is a city in north western Tunisia and the capital of the Kef Governorate.Situated in the northwest of the country, to the west of Tunis and some east of the border between Algeria and Tunisia, El Kef has a population of . The old town is built on the cliff face...

, Tunisia

Tunisia

Tunisia , officially the Tunisian RepublicThe long name of Tunisia in other languages used in the country is: , is the northernmost country in Africa. It is a Maghreb country and is bordered by Algeria to the west, Libya to the southeast, and the Mediterranean Sea to the north and east. Its area...

 was appointed as a reference profile (GSSP) for this important boundary. The Danian is the oldest age of the Paleocene, defined at its base by the K-Pg boundary. It is very important because the readily recognized iridium anomaly and primitive Danian planktonic foraminifers define the base of the Danian. Danian foraminiferans repopulated the Paleocene seas after the Cretaceous mass extinction (Olsson et al., 1996). The first replacement foraminiferan of the Paleogene is the Globigerina eugubina, which is used to define the base of the Danian Age (Stainforth et al., 1975). This foraminiferan replaced the Cretaceous genus Globotruncana.

The top of the Danian stage (the base of the Selandian) is close to the boundary between biozone

Biozone

Biostratigraphic units or Biozones are intervals of geological strata that are defined on the basis of their characteristic fossil taxa....

s NP4 and NP5 from marine biostratigraphy

Biostratigraphy

Biostratigraphy is the branch of stratigraphy which focuses on correlating and assigning relative ages of rock strata by using the fossil assemblages contained within them. Usually the aim is correlation, demonstrating that a particular horizon in one geological section represents the same period...

. It is slighltly after the first appearances of many new species of the calcareous nannoplankton genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 Fasciculithus (F. ulii, F. billii, F. janii, F. involutus, F. tympaniformis and F. pileatus) and close to the first appearance of calcareous nannoplankton species Neochiastozygus perfectus.

The Danian stage overlaps the Puercan

Puercan

The Puercan North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology , typically set from 65,000,000 to 63,300,000 years BP lasting . It is usually considered to be within the Paleocene...

 and Torrejonian

Torrejonian

The Torrejonian North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology , typically set from 63,300,000 to 60,200,000 years BP lasting . It is usually considered to overlap the Selandian and Thanetian within the...

 North American Land Mammal Ages

North American Land Mammal Ages

The North American Mammal Ages establishes a geologic timescale for prehistoric North American fauna beginning 66.5 Ma during the Paleocene and continuing through to the Late Pleistocene...

 and the Shanghuan and lowest part of the Nongshanian Asian Land Mammal Ages

Asian land mammal ages

The Asian Land Mammal Ages establishes a geologic timescale for prehistoric Asian fauna beginning 58.7 Mya during the Paleogene and continuing through to the Middle Pleistocene...

. It includes the oldest Mammal Paleogene zones, all included in the 1 - 5 group.

Palaeontology

Though the dinosaur

Dinosaur

Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...

s were gone, the mammals, and other land animals remained small, none bigger than a large domestic cat. But most of the mammals' orders

Order (biology)

In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...

 already had appeared. Numerous lineages of modern birds also survived, particularly in the area around Australia

Australia

Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

 but also elsewhere, e.g. Scaniornis

Scaniornis

Scaniornis is a prehistoric bird genus. The only species, Scaniornis lundgreni, lived in the MP 1-5 ....

of the North Sea

North Sea

In the southwest, beyond the Straits of Dover, the North Sea becomes the English Channel connecting to the Atlantic Ocean. In the east, it connects to the Baltic Sea via the Skagerrak and Kattegat, narrow straits that separate Denmark from Norway and Sweden respectively...

 region. The oceans remained much the same as the Late Cretaceous

Late Cretaceous

The Late Cretaceous is the younger of two epochs into which the Cretaceous period is divided in the geologic timescale. Rock strata from this epoch form the Upper Cretaceous series...

 seas, only that there was less life, no marine reptile

Reptile

Reptiles are members of a class of air-breathing, ectothermic vertebrates which are characterized by laying shelled eggs , and having skin covered in scales and/or scutes. They are tetrapods, either having four limbs or being descended from four-limbed ancestors...

s, and other lesser known animals.

Literature

; 1847: Sur le terrain Danien, nouvel étage de la craie, Bulletin de la Societé Géologique de France, série 2, 3, p. 179-181, ISSN 0037-9409.; 2004: A Geologic Time Scale 2004, Cambridge University Press

Cambridge University Press

Cambridge University Press is the publishing business of the University of Cambridge. Granted letters patent by Henry VIII in 1534, it is the world's oldest publishing house, and the second largest university press in the world...

.; 2006: The Global Boundary Stratotype Section and Point for the base of the Danian Stage (Paleocene, Paleogene, "Tertiary", Cenozoic) at El Kef, Tunisia: original definition and revision, Episodes 29(4), p. 263-273, ISSN 0705-3797.; 1996:The Cretaceous-Tertiary catastrophe event at Millers Ferry, Alabama in Ryder, G., Fastovsky, D., and Gartner, S., eds., The Cretaceous-Tertiary Event and other catastrophes in Earth history: Geological Society of America Special Paper 307, p. 263-277.; 1975: Cenozoic planktonic foraminifera zonation and characteristics of index forms: The University of Kansas Paleontological Institute, Article 62, 425 p.

External links

• GeoWhen Database - Danian
• 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