age
Age or AGE may refer to:
Time and its effects
* Age, the amount of time someone or something has been alive or 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 or stages may refer to:
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 British theatre newspaper
* St ...
Series
Series may refer to:
People with the name
* Caroline Series (born 1951), English mathematician, daughter of George Series
* George Series (1920–1995), English physicist
Arts, entertainment, and media
Music
* Series, the ordered sets used in ...
. It spans the time between 93.9 ± 0.8 Ma and 89.8 ± 1 Ma (million years ago). The Turonian is preceded by the Cenomanian Stage and underlies the
Coniacian
The Coniacian is an age or stage in the geologic timescale. It is a subdivision of the Late Cretaceous Epoch or Upper Cretaceous Series and spans the time between 89.8 ± 1 Ma and 86.3 ± 0.7 Ma (million years ago). The Coniacian is preceded by t ...
Stage.
At the beginning of the Turonian an oceanic anoxic event (OAE 2) took place, also referred to as the
Cenomanian-Turonian boundary event
The Cenomanian-Turonian boundary event, also known as the Cenomanian-Turonian extinction, Cenomanian-Turonian oceanic anoxic event ( OAE 2), and referred to also as the Bonarelli event, was one of two anoxic extinction events in the Cretaceous p ...
or the "Bonarelli Event".
Stratigraphic definition
The Turonian (French: ''Turonien'') was defined by the
French
French (french: français(e), link=no) may refer to:
* Something of, from, or related to France
** French language, which originated in France, and its various dialects and accents
** French people, a nation and ethnic group identified with Franc ...
paleontologist
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 anthropol ...
(1802–1857) in 1842. Orbigny named it after the French city of
Tours
Tours ( , ) is one of the largest cities in the region of Centre-Val de Loire, France. It is the prefecture of the department of Indre-et-Loire. The commune of Tours had 136,463 inhabitants as of 2018 while the population of the whole metrop ...
in the region of
Touraine
Touraine (; ) is one of the traditional provinces of France. Its capital was Tours. During the political reorganization of French territory in 1790, Touraine was divided between the departments of Indre-et-Loire, :Loir-et-Cher, Indre and Vienn ...
(department
Indre-et-Loire
Indre-et-Loire () is a department in west-central France named after the Indre River and Loire River. In 2019, it had a population of 610,079.type locality.
The base of the Turonian Stage is defined as the place where the
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 cuttlefish ...
species '' Watinoceras devonense'' first appears in the stratigraphic column. The official reference profile (the GSSP) for the base of the Turonian is located in the Rock Canyon anticline near
Pueblo, Colorado
Pueblo () is a home rule municipality that is the county seat and the most populous municipality of Pueblo County, Colorado, United States. The city population was 111,876 at the 2020 United States Census, making Pueblo the ninth most popu ...
(United States, coordinates: 38° 16' 56" N, 104° 43' 39" W).The GSSP was established by Kennedy ''et al.'' (2005)
The top of the Turonian Stage (the base of the Coniacian) is defined as the place in the stratigraphic column where the
inoceramid
The Inoceramidae are an extinct family of bivalves ("clams") in the Class Mollusca. Fossils of inoceramids are found in marine sediments of Permian to latest Cretaceous in age. Inoceramids tended to live in upper bathyal and neritic environments ...
bivalve
Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. As a group, biva ...
species ''
Cremnoceramus rotundatus
''Cremnoceramus'' ("cremno-" = ''kremnos'' reek precipice or over hanging wall or bank; "ceramus" = ''keramos'' reek clay pot) is an extinct genus of fossil marine pteriomorphian bivalves that superficially resembled the related winged pearly o ...
'' first appears.
Subdivision
The Turonian is sometimes subdivided in Lower/Early, Middle and Upper/Late substages or subages. In the Tethys domain, it contains the following ammonite
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 o ...
index fossil
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.Hine, Robert. “Biostratigraphy.” ''Oxford Reference: Dictionary of Bi ...
Inoceramus
''Inoceramus'' (Greek: translation "strong pot") is an extinct genus of fossil marine pteriomorphian bivalves that superficially resembled the related winged pearly oysters of the extant genus '' Pteria''. They lived from the Early Jurassic to ...
'' (''I. schloenbachi'', ''I. lamarcki'' and ''I. labiatus''). Inoceramids are bivalve Mollusca related to today's mussels.
References
Literature
*; 2004: ''A Geologic Time Scale 2004'', Cambridge University Press.
*; 2005: ''The Global Boundary Stratotype Section and Point for the base of the Turonian Stage of the Cretaceous: Pueblo, Colorado, U.S.A.'', Episodes 28(2): pp 93–104.