View source for Tortonian

{{Short description|Geologic age of the late Miocene}}
{{Infobox geologic timespan
| name                         = Tortonian
| color                        = Tortonian
| time_start                   = 11.63
| time_end                     = 7.246
| image_map                    =File:010_mya.png
| caption_map                  =An map of the world 10 million years ago, during the Tortonian Age.
| image_outcrop                =
| caption_outcrop              =
| image_art                    =
| caption_art                  =
<!--Chronology-->  
| timeline                     = Neogene
| formerly_part_of             = [[Tertiary period|Tertiary]] [[Geological period|Period]]/[[System (stratigraphy)|System]]
| partially_contained_in       =
| partially_contains           =
<!--Etymology-->
| name_formality               = Formal
| name_accept_date             =
| alternate_spellings          =
| synonym1                     =
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| synonym3                     =
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<!--Usage Information--> 
| celestial_body               = earth
| usage                        = Global ([[International Commission on Stratigraphy|ICS]])
| timescales_used              = ICS Time Scale
| formerly_used_by             =
| not_used_by                  =
<!--Definition-->
| chrono_unit                  = Age
| strat_unit                   = Stage
| proposed_by                  = 
| type_section                 =
| timespan_formality           = Formal
| lower_boundary_def           = LAD of the [[Haptophyte]] ''[[Discoaster|Discoaster kugleri]]''
| lower_gssp_location          = Monte dei Corvi Beach section, [[Ancona]], [[Italy]]
| lower_gssp_coords            = {{Coord|43.5867|N|13.5694|E|display=inline}}
| lower_gssp_accept_date       = 2003<ref>{{cite journal|last=Hilgen |first=F. J. |author2=Hayfaa Abdul Aziz |last3=Bice |first3=David |last4=Iaccarino |first4=Silvia |last5=Krijgsman |first5=Wout |last6=Kuiper |first6=Klaudia |last7=Montanari |first7=Alessandro |last8=Raffi |first8=Isabella |last9=Turco |first9=Elena |author10=Willem-Jan Zachariasse |title=The Global boundary Stratotype Section and Point (GSSP) of the Tortonian Stage (Upper Miocene) at Monte Dei Corvi |journal=Episodes |year=2005 |volume=28 |issue=1 |pages=6–17 |url=https://stratigraphy.org/gssps/files/tortonian.pdf |access-date=26 December 2020 |doi=10.18814/epiiugs/2005/v28i1/001 |doi-access=free }}</ref>
| upper_boundary_def           = 
* First regular occurrence of the [[Foraminifera|Planktonic Foraminifer]] ''[[Globorotalia|Globorotalia miotumida]]''
* [[First appearance datum|FAD]] of the [[Haptophyte]] ''[[Amaurolithus|Amaurolithus delicatus]]''
| upper_gssp_location          = Oued Akrech section, [[Rabat]], [[Morocco]]
| upper_gssp_coords            = {{Coord|33.9369|N|6.8125|W|display=inline}}
| upper_gssp_accept_date       = January 2000<ref>{{cite journal|last=Hilgen|first=F. J.|author2=S. Iaccarino |author3=W. Krijgsman |author4=G. Villa |author5=C. G. Langereis |author6=W. J. Zachariasse |title=The Global Boundary Stratotype Section and Point (GSSP) of the Messinian Stage (uppermost Miocene)|journal=Episodes|year=2000|volume=23|issue=3|pages=172–178|url=http://www.stratigraphy.org/GSSP/file6.pdf|doi=10.18814/epiiugs/2000/v23i3/004|doi-access=free}}</ref>
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}}

The '''Tortonian''' is in the [[geologic time scale]] an [[age (geology)|age]] or [[stage (stratigraphy)|stage]] of the [[late Miocene]] that spans the time between 11.608 ± 0.005 [[Ma (unit)|Ma]] and 7.246 ± 0.005 Ma (million years ago).<ref name="ICS"/> It follows the [[Serravallian]] and is followed by the [[Messinian]].

The Tortonian roughly overlaps with the regional Pannonian Stage of the [[Paratethys]] timescale of Central Europe. It also overlaps the upper [[Astaracian]], [[Vallesian]] and lower [[Turolian]] [[European land mammal age]]s, the upper [[Clarendonian]] and lower [[Hemphillian]] [[North American land mammal age]]s and the upper [[Chasicoan]] and lower [[Huayquerian]] [[South American land mammal age]]s.

==Definition==
The Tortonian was introduced by Swiss [[stratigrapher]] [[Karl Mayer-Eymar]] in 1858. It was named after the Italian city of [[Tortona]] in the [[Piedmont]] region.

The base of the Tortonian Stage is at the last common appearance of calcareous [[nanoplankton]] ''[[Discoaster kugleri]]'' and planktonic [[foram]] ''[[Globigerinoides|Globigerinoides subquadratus]]''. It is also associated with the short normal polarized magnetic chronozone C5r.2n. A [[GSSP]] for the Tortonian has been established in the Monte dei Corvi section near [[Ancona]] (Italy).<ref>By Hilgen ''et al.'' (2005)</ref>

The top of the Tortonian (the base of the [[Messinian]]) is at the first appearance of the planktonic foram species ''[[Globorotalia conomiozea]]'' and is stratigraphically in the middle of magnetic chronozone C3Br.1r.

==Geologic history==
In 2020, geologists reported two newly-identified [[supervolcano]] [[List_of_largest_volcanic_eruptions|eruptions]] associated with the [[Yellowstone hotspot]] track, including the region's largest and most cataclysmic event &ndash; the Grey's Landing super-eruption &ndash; which had a volume of at least {{convert|2,800|km3|abbr=off}} and occurred around 8.72 Ma.<ref>{{cite journal|first1=T.R.|last1=Knott|first2=M.J.|last2=Branney|first3=M.K.|last3=Reichow|first4=D.R.|last4=Finn|first5=S.|last5=Tapster|first6=R.S.|last6=Coe|title=Discovery of two new super-eruptions from the Yellowstone hotspot track (USA): Is the Yellowstone hotspot waning?|journal=Geology|doi=10.1130/G47384.1|year=2020|volume=48|issue=9 |pages=934–938 |bibcode=2020Geo....48..934K |doi-access=free}}</ref><ref>{{cite news|url=https://www.geosociety.org/GSA/News/pr/2020/20-18.aspx|title=Discovery of Ancient Super-Eruptions Indicates the Yellowstone Hotspot May Be Waning |date=3 June 2020|access-date=17 June 2020|work=The Geological Society of America}}</ref>

Around 10 Ma, the inflow of [[North Atlantic Deep Water]] (NADW) into the [[Indian Ocean]] increased significantly.<ref>{{Cite journal |last=Banerjee |first=Barnita |last2=Ahmad |first2=Syed Masood |last3=Raza |first3=Waseem |last4=Raza |first4=Tabish |date=15 January 2017 |title=Paleoceanographic changes in the Northeast Indian Ocean during middle Miocene inferred from carbon and oxygen isotopes of foraminiferal fossil shells |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018216307210 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |language=en |volume=466 |pages=166–173 |doi=10.1016/j.palaeo.2016.11.021 |access-date=1 February 2025 |via=Elsevier Science Direct|url-access=subscription }}</ref>

== References ==

===Notes===
<references/>

===Literature===
{{Wikisource portal|Cenozoic#Neogene}}
*{{smallcaps|Gradstein, F.M.; Ogg, J.G. & Smith, A.G.}}; '''2004''': ''A Geologic Time Scale 2004'', Cambridge University Press.
*{{smallcaps|Hilgen, F.; Abdul Aziz, H.; Bice, D.; Iaccarino, S.; Krijgsman, W.; Kuiper, K.; Montanari, A.; Raffi, I.; Turco, E. & Zachariasse, W.-J.}}; '''2005''': ''The Global boundary Stratotype Section and Point (GSSP) of the Tortonian Stage (Upper Miocene) at Monte Dei Corvi'', Episodes '''28''', p.&nbsp;6-17.
*{{smallcaps|Mayer-Eymar, K.}}; '''1858''': ''Versuch einer neuen Klassifikation der Tertiär-Gebilde Europa’s'', Verhandlungen der Schweizerischen Naturforschenden Gesellschaft, Jahresversammlung 1857, p.&nbsp;70–71 & 165–199. {{in lang|de}}

==External links==
*[http://www.stratigraphy.org/bak/geowhen/stages/Tortonian.html GeoWhen Database - Tortonian]
*[http://stratigraphy.science.purdue.edu/charts/Timeslices/1_Neogene.pdf Neogene timescale], at the website of the subcommission for stratigraphic information of the ICS
* [https://web.archive.org/web/20060518100615/http://norges.uio.no/timescale/F5a_Neo1.pdf Neogene timescale] at the website of the Norwegian network of offshore records of geology and stratigraphy

{{Neogene footer}}
{{Geological history of Earth|p|c}}

[[Category:Tortonian| ]]
[[Category:Miocene|*05]]
[[Category:Tortonian first appearances| ]]
[[Category:Miocene geochronology]]
[[Category:Geological ages]]