View source for Biology: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                    =
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<!--Chronology-->  
| timeline                     = Neogene
| formerly_part_of             = [[Earth:Tertiary|Tertiary]] [[Earth:Geological period|Period]]/[[Earth:System (stratigraphy)|System]]
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<!--Etymology-->
| name_formality               = Formal
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<!--Usage Information--> 
| celestial_body               = earth
| usage                        = Global ([[Organization:International Commission on Stratigraphy|ICS]])
| timescales_used              = ICS Time Scale
| formerly_used_by             =
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<!--Definition-->
| chrono_unit                  = Age
| strat_unit                   = Stage
| proposed_by                  = 
| type_section                 =
| timespan_formality           = Formal
| lower_boundary_def           = LAD of the [[Biology:Haptophyte|Haptophyte]] ''[[Biology: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 [[Biology:Foraminifera|Planktonic Foraminifer]] ''[[Biology:Globorotalia|Globorotalia miotumida]]''
* [[Earth:First appearance datum|FAD]] of the [[Biology:Haptophyte|Haptophyte]] ''Amaurolithus delicatus''
| upper_gssp_location          = Oued Akrech section, [[Place:Rabat|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 [[Earth:Geologic time scale|geologic time scale]] an [[Earth:Age (geology)|age]] or [[Physics:Stage (stratigraphy)|stage]] of the late Miocene that spans the time between 11.608 ± 0.005 Ma and 7.246 ± 0.005 Ma (million years ago). It follows the [[Earth:Serravallian|Serravallian]] and is followed by the [[Biology:Messinian|Messinian]].

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

The base of the Tortonian Stage is at the last common appearance of calcareous nanoplankton ''Discoaster kugleri'' and planktonic foram ''[[Biology: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 [[Biology:Messinian|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 [[Earth:Supervolcano|supervolcano]] eruptions associated with the [[Earth:Yellowstone hotspot|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 2,800 km<sup>3</sup> 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>

== References ==

===Notes===
<references/>

===Literature===
*{{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

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

[[Category:Tortonian first appearances| ]]

{{Sourceattribution|Tortonian}}