View source for Neogene

{{Short description|Second geologic period in the Cenozoic Era}}
{{Redirect|Neogenic|the fictional item featured in Marvel comics and animated series|Neogenic (comics)}}
{{for|the moth genus|Neogene (moth){{!}}''Neogene'' (moth)}}
{{Infobox geologic timespan
| name                         = Neogene
| color                        = Neogene
| top_bar                      =
| time_start                   = 23.04
| time_end                     = 2.58
| image_map                    = Mollweide Paleographic Map of Earth, 15 Ma (Langhian Age).png 
| caption_map                  = A map of Earth as it appeared 15 million years ago during the Neogene Period, Miocene Epoch
| image_outcrop                =
| caption_outcrop              =
| image_art                    =
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<!--Chronology-->  
| timeline                     = Neogene
<!--Etymology-->
| name_formality               = Formal
| name_accept_date             =
| alternate_spellings          =
| synonym1                     =
| synonym1_coined              =
| synonym2                     =
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| synonym3                     =
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| nicknames                    =
| former_names                 =
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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                  = Period
| strat_unit                   = System
| proposed_by                  =
| timespan_formality           = Formal
| lower_boundary_def           =
* Base of magnetic polarity [[chronozone]] C6Cn.2n
* [[First appearance datum|FAD]] of the [[Foraminifera|Planktonic foraminiferan]] ''[[Paragloborotalia|Paragloborotalia kugleri]]''
| lower_gssp_location          = Lemme-Carrosio Section, [[Carrosio]], [[Italy]]
| lower_gssp_coords            = {{Coord|44.6589|N|8.8364|E|display=inline}}
| lower_gssp_accept_date       = 1996<ref name="Steininger 1997">{{cite journal|last=Steininger|first=Fritz F. |author2=M. P. Aubry |author3=W. A. Berggren |author4=M. Biolzi |author5=A. M. Borsetti |author6=Julie E. Cartlidge |author7=F. Cati |author8=R. Corfield |author9=R. Gelati |author10=S. Iaccarino |author11=C. Napoleone |author12=F. Ottner |author13=F. Rögl |author14=R. Roetzel |author15=S. Spezzaferri |author16=F. Tateo |author17=G. Villa |author18=D. Zevenboom |title=The Global Stratotype Section and Point (GSSP) for the base of the Neogene|journal=Episodes|year=1997|volume=20|issue=1|pages=23–28|url=http://www.stratigraphy.org/GSSP/file9.pdf|doi=10.18814/epiiugs/1997/v20i1/005 |doi-access=free }}</ref>
| upper_boundary_def           = 
* Base of magnetic polarity chronozone C2r (Matuyama).
* Extinction of the [[Haptophyte]]s ''[[Discoaster|Discoaster pentaradiatus]]'' and ''[[Discoaster|Discoaster surculus]]''
| upper_gssp_location          = Monte San Nicola Section, [[Gela]], [[Sicily]], [[Italy]]
| upper_gssp_coords            = {{Coord|37.1469|N|14.2035|E|display=inline}}
| upper_gssp_accept_date       = 2009 (as base of Quaternary and Pleistocene)<ref>{{cite journal |last1=Gibbard |first1=Philip |last2=Head |first2=Martin |title=The newly-ratified definition of the Quaternary System/Period and redefinition of the Pleistocene Series/Epoch, and comparison of proposals advanced prior to formal ratification |journal=Episodes |date=September 2010 |volume=33 |issue=3 |pages=152–158 |doi=10.18814/epiiugs/2010/v33i3/002 |doi-access=free |url=https://stratigraphy.org/gssps/files/quaternary-pleistocene.pdf |access-date=8 December 2020}}</ref>
<!--Atmospheric and Climatic Data-->
| o2                           = 21.5
| co2                          = 280
| temp                         = 14
| sea_level                    =
}}

The '''Neogene''' ({{IPAc-en|ˈ|n|iː|.|ə|dʒ|iː|n}} {{respell|NEE|ə|jeen}},<ref>{{cite Merriam-Webster|Neogene}}</ref><ref>{{cite Dictionary.com|Neogene}}</ref>) is a [[Geologic time scale#Terminology|geologic period and system]] that spans 20.45 million years from the end of the [[Paleogene]] Period {{period end|Paleogene}} Ma (million years ago) to the beginning of the present [[Quaternary]] Period {{period start|quaternary}} Ma. It is the second period of the [[Cenozoic]] and the eleventh period of the [[Phanerozoic]]. The Neogene is sub-divided into two [[Epoch (geology)|epoch]]s, the earlier [[Miocene]] and the later [[Pliocene]]. Some geologists assert that the Neogene cannot be clearly delineated from the modern geological period, the [[Quaternary]].<ref name="tucker-2001"/> The term "Neogene" was coined in 1853 by the Austrian palaeontologist [[Moritz Hoernes|Moritz Hörnes]] (1815–1868).<ref>{{cite journal |last1=Hörnes |first1=M. |title=Mittheilungen an Professor Bronn gerichtet |journal=Neues Jahrbuch für Mineralogie, Geognosie, Geologie und Petrefaktenkunde |date=1853 |pages=806–810 |url=https://babel.hathitrust.org/cgi/pt?id=hvd.32044106271273;view=1up;seq=828 |trans-title=Reports addressed to Professor Bronn |language=de|quote=From p. 806:  ''"Das häufige Vorkommen der Wiener Mollusken … im trennenden Gegensatze zu den eocänen zusammenzufassen."'' (The frequent occurrence of Viennese mollusks in typical Miocene as well as in typical Pliocene deposits motivated me – in order to avoid the perpetual monotony [of providing] details about the deposits – to subsume both deposits provisionally under the name "Neogene" (νεος new and γιγνομαι to arise) in distinguishing contrast to the Eocene.)|hdl=2027/hvd.32044106271273}}</ref> The earlier term [[Tertiary (period)|Tertiary]] Period was used to define the span of time now covered by Paleogene and Neogene and, despite no longer being recognized as a formal [[stratigraphy|stratigraphic term]], "Tertiary" still sometimes remains in informal use.<ref>{{Cite web|url=http://www.stratigraphy.org/bak/geowhen/TQ.html|title=GeoWhen Database – What Happened to the Tertiary?|website=www.stratigraphy.org}}</ref>

During this period, [[mammal]]s and [[bird]]s continued to evolve into modern forms, while other groups of life remained relatively unchanged. The first humans (''[[Homo habilis]]'') appeared in Africa near the end of the period.<ref name="homo-habilis">{{cite journal |last1=Spoor |first1=Fred |last2=Gunz |first2=Philipp |last3=Neubauer |first3=Simon |last4=Stelzer |first4=Stefanie |last5=Scott |first5=Nadia |last6=Kwekason |first6=Amandus |last7=Dean |first7=M. Christopher |title=Reconstructed Homo habilis type OH 7 suggests deep-rooted species diversity in early Homo |journal=Nature |date=March 2015 |volume=519 |issue=7541 |pages=83–86 |doi=10.1038/nature14224|pmid=25739632 |bibcode=2015Natur.519...83S |s2cid=4470282 }}</ref> Some continental movements took place, the most significant event being the connection of [[North America|North]] and [[South America]] at the [[Isthmus of Panama]], late in the Pliocene. This cut off the warm ocean currents from the Pacific to the Atlantic Ocean, leaving only the [[Gulf Stream]] to transfer heat to the [[Arctic Ocean]]. The global climate cooled considerably throughout the Neogene, culminating in a series of continental [[Quaternary glaciation|glaciations]] in the [[Quaternary]] Period that followed.

==Divisions==
In ICS terminology, from upper (later, more recent) to lower (earlier):

The [[Pliocene]] Epoch is subdivided into two ages:

* [[Piacenzian]] Age, preceded by
* [[Zanclean]] Age

The [[Miocene]] Epoch is subdivided into six ages:

* [[Messinian]] Age, preceded by
* [[Tortonian]] Age
* [[Serravallian]] Age
* [[Langhian]] Age
* [[Burdigalian]] Age
* [[Aquitanian (stage)|Aquitanian]] Age
 
In different geophysical regions of the world, other regional names are also used for the same or overlapping ages and other timeline subdivisions.

The terms ''Neogene System'' (formal) and ''Upper Tertiary System'' (informal) describe the rocks deposited during the ''Neogene Period''.

==Paleogeography==
The continents in the Neogene were very close to their current positions. The [[Isthmus of Panama]] formed, connecting [[North America|North]] and [[South America]]. The [[Indian subcontinent]] continued to collide with [[Asia]], forming the [[Himalayas]]. Sea levels fell, creating [[land bridge]]s between [[Africa]] and [[Eurasia]] and between Eurasia and North America.

==Climate==
The global climate became more seasonal and continued an overall drying and cooling trend which began during the [[Paleogene]]. The [[Early Miocene]] was relatively cool;<ref name="ChristopherScotese">{{Cite journal |last1=Scotese |first1=Christopher R. |last2=Song |first2=Haijun |last3=Mills |first3=Benjamin J.W. |last4=van der Meer |first4=Douwe G. |date=April 2021 |title=Phanerozoic paleotemperatures: The earth's changing climate during the last 540 million years |url=https://www.researchgate.net/publication/348351275 |journal=[[Earth-Science Reviews]] |volume=215 |article-number=103503 |bibcode=2021ESRv..21503503S |doi=10.1016/j.earscirev.2021.103503 |issn=0012-8252 |archive-url=https://web.archive.org/web/20210108000000/http://dx.doi.org/10.1016/j.earscirev.2021.103503 |archive-date=8 January 2021 |s2cid=233579194 |access-date=17 July 2023}} [https://eprints.whiterose.ac.uk/169823/ Alt URL]</ref> Early Miocene mid-latitude seawater and continental thermal gradients were already very similar to those of the present.<ref name="GoedertEtAl2017">{{cite journal |last1=Goedert |first1=Jean |last2=Amiot |first2=Romain |last3=Arnaut-Godet |first3=Florent |last4=Cuny |first4=Gilles |last5=Fourel |first5=François |last6=Hernandez |first6=Jean-Alexis |last7=Pedreira-Segade |first7=Ulysse |last8=Lécuyer |first8=Christophe |date=1 September 2017 |title=Miocene (Burdigalian) seawater and air temperatures estimated from the geochemistry of fossil remains from the Aquitaine Basin, France |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018216307568 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=481 |pages=14–28 |doi=10.1016/j.palaeo.2017.04.024 |bibcode=2017PPP...481...14G |access-date=30 November 2022|url-access=subscription }}</ref> During the [[Middle Miocene]], Earth entered a warm phase known as the Middle Miocene Climatic Optimum (MMCO),<ref name="ChristopherScotese" /> which was driven by the emplacement of the [[Columbia River Basalt Group]].<ref>{{cite journal |last1=Kasbohm |first1=Jennifer |last2=Schoene |first2=Blair |date=19 September 2018 |title=Rapid eruption of the Columbia River flood basalt and correlation with the mid-Miocene climate optimum |journal=[[Science Advances]] |volume=4 |issue=9 |article-number=eaat8223 |doi=10.1126/sciadv.aat8223 |pmid=30255148 |pmc=6154988 |bibcode=2018SciA....4.8223K }}</ref> Around 11 Ma, the Middle Miocene Warm Interval gave way to the much cooler Late Miocene.<ref name="ChristopherScotese" /> The ice caps on both poles began to grow and thicken, a process enhanced by positive feedbacks from increased formation of sea ice.<ref>{{cite journal |last1=DeConto |first1=Robert |last2=Pollard |first2=David |last3=Harwood |first3=David |date=24 August 2007 |title=Sea ice feedback and Cenozoic evolution of Antarctic climate and ice sheets |journal=[[Paleoceanography and Paleoclimatology]] |volume=22 |issue=3 |pages=1–18 |doi=10.1029/2006PA001350 |doi-access=free |bibcode=2007PalOc..22.3214D }}</ref> Between 7 and 5.3 Ma, a decrease in global temperatures termed the Late Miocene Cooling (LMC) ensued, driven by decreases in carbon dioxide concentrations.<ref>{{cite journal |last1=Tanner |first1=Thomas |last2=Hernández-Almeida |first2=Iván |last3=Drury |first3=Anna Joy |last4=Guitián |first4=José |last5=Stoll |first5=Heather |date=10 December 2020 |title=Decreasing Atmospheric CO2 During the Late Miocene Cooling |url=https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2020PA003925 |journal=[[Paleoceanography and Paleoclimatology]] |volume=35 |issue=12 |doi=10.1029/2020PA003925 |bibcode=2020PaPa...35.3925T |s2cid=230534117 |access-date=17 March 2023|url-access=subscription }}</ref> During the Pliocene, from about 5.3 to 2.7 Ma, another warm interval occurred, being known as the Pliocene Warm Interval (PWI), interrupting the longer-term cooling trend. The [[Middle Pliocene Warm Period|Pliocene Thermal Maximum]] (PTM) occurred between 3.3 and 3.0 Ma.<ref name="ChristopherScotese" /> During the Pliocene, [[Green Sahara]] phases of wet conditions in [[North Africa]] were frequent and occurred about every 21 kyr, being especially intense when Earth's orbit's eccentricity was high.<ref>{{Cite journal |last1=Lupien |first1=Rachel |last2=Uno |first2=Kevin |last3=Rose |first3=Cassaundra |last4=deRoberts |first4=Nicole |last5=Hazan |first5=Cole |last6=de Menocal |first6=Peter |last7=Polissar |first7=Pratigya |date=9 October 2023 |title=Low-frequency orbital variations controlled climatic and environmental cycles, amplitudes, and trends in northeast Africa during the Plio-Pleistocene |journal=[[Communications Earth & Environment]] |language=en |volume=4 |issue=1 |page=360 |doi=10.1038/s43247-023-01034-7 |issn=2662-4435 |doi-access=free |bibcode=2023ComEE...4..360L }}</ref> The PWI had similar levels of atmospheric carbon dioxide to contemporary times and is often seen as an analogous climate to the projected climate of the near future as a result of [[Climate change|anthropogenic global warming]].<ref>{{Cite journal |last1=Burke |first1=K. D. |last2=Williams |first2=J. W. |last3=Chandler |first3=M. A. |last4=Haywood |first4=A. M. |last5=Lunt |first5=D. J. |last6=Otto-Bliesner |first6=B. L. |date=26 December 2018 |title=Pliocene and Eocene provide best analogs for near-future climates |journal=[[Proceedings of the National Academy of Sciences of the United States of America]] |language=en |volume=115 |issue=52 |pages=13288–13293 |doi=10.1073/pnas.1809600115 |doi-access=free |issn=0027-8424 |pmc=6310841 |pmid=30530685 |bibcode=2018PNAS..11513288B }}</ref> Towards the end of the Pliocene, decreased heat transport towards the Antarctic resulting from a weakening of the [[Indonesian Throughflow]] (ITF) cooled the Earth, a process that exacerbated itself in a positive feedback as sea levels dropped and the ITF diminished and further limited the heat transported southward by the [[Leeuwin Current]].<ref>{{Cite journal |last1=De Vleeschouwer |first1=David |last2=Auer |first2=Gerald |last3=Smith |first3=Rebecca |last4=Bogus |first4=Kara |last5=Christensen |first5=Beth |last6=Groeneveld |first6=Jeroen |last7=Petrick |first7=Benjamin |last8=Henderiks |first8=Jorijntje |last9=Castañeda |first9=Isla S. |last10=O'Brien |first10=Evan |last11=Ellinghausen |first11=Maret |last12=Gallagher |first12=Stephen J. |last13=Fulthorpe |first13=Craig S. |last14=Pälike |first14=Heiko |date=October 2018 |title=The amplifying effect of Indonesian Throughflow heat transport on Late Pliocene Southern Hemisphere climate cooling |url=https://linkinghub.elsevier.com/retrieve/pii/S0012821X18304412 |journal=[[Earth and Planetary Science Letters]] |language=en |volume=500 |pages=15–27 |doi=10.1016/j.epsl.2018.07.035 |bibcode=2018E&PSL.500...15D |access-date=13 April 2024 |via=Elsevier Science Direct|url-access=subscription }}</ref> By the end of the period the first of a series of glaciations of the [[Quaternary glaciation|current Ice Age]] began.<ref>{{cite book |last1=Benn |first1=Douglas I. |title=Glaciers & glaciation |date=2010 |publisher=Hodder Education |location=London |isbn=978-0-340-90579-1 |pages=15–21 |edition=2nd}}</ref>

==Flora and fauna==
Marine and continental flora and fauna have a modern appearance. The reptile group [[Choristodera]] went extinct in the early part of the period, while the amphibians known as [[Albanerpetontidae|Allocaudata]] disappeared at the end of it. Neogene also marked the end of the reptilian genera ''[[Langstonia]]'' and ''[[Barinasuchus]]'', terrestrial predators that were the last surviving members of [[Sebecosuchia]], a group related to crocodiles. The oceans were dominated by large carnivores like [[megalodon]]s and [[livyatan]]s, and 19 million years ago about 70% of all pelagic shark species disappeared.<ref>[https://www.discovermagazine.com/environment/almost-20-million-years-ago-sharks-nearly-went-extinct-nobody-knows-why Almost 20 Million Years Ago, Sharks Nearly Went Extinct]</ref> [[Mammal]]s and [[bird]]s continued to be the dominant terrestrial vertebrates, and took many forms as they adapted to various habitats. [[Ungulate|Ungulates]] in North America became noticeably more [[cursorial]] and increased their stride lengths across the Oligocene-Miocene boundary, likely in response to the increased habitat openness during the Miocene.<ref>{{Cite journal |last1=Levering |first1=David |last2=Hopkins |first2=Samantha |last3=Davis |first3=Edward |date=15 January 2017 |title=Increasing locomotor efficiency among North American ungulates across the Oligocene-Miocene boundary |url=https://www.sciencedirect.com/science/article/pii/S0031018216307738 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |language=en |volume=466 |pages=279–286 |doi=10.1016/j.palaeo.2016.11.036 |bibcode=2017PPP...466..279L |access-date=13 February 2022 |via=Elsevier Science Direct|url-access=subscription }}</ref> An explosive radiation of ursids took place at the Miocene-Pliocene boundary.<ref>{{Cite journal |last1=Krause |first1=Johannes |last2=Unger |first2=Tina |last3=Noçon |first3=Aline |last4=Malaspinas |first4=Anna-Sapfo |last5=Kolokotronis |first5=Sergios-Orestis |last6=Stiller |first6=Mathias |last7=Soibelzon |first7=Leopoldo |last8=Spriggs |first8=Helen |last9=Dear |first9=Paul H |last10=Briggs |first10=Adrian W |last11=Bray |first11=Sarah CE |last12=O'Brien |first12=Stephen J |last13=Rabeder |first13=Gernot |last14=Matheus |first14=Paul |last15=Cooper |first15=Alan |last16=Slatkin |first16=Montgomery |last17=Pääbo |first17=Svante |last18=Hofreiter |first18=Martin |date=28 July 2008 |title=Mitochondrial genomes reveal an explosive radiation of extinct and extant bears near the Miocene-Pliocene boundary |journal=[[BMC Evolutionary Biology]] |language=en |volume=8 |issue=1 |page=220 |doi=10.1186/1471-2148-8-220 |doi-access=free |issn=1471-2148 |pmc=2518930 |pmid=18662376 |bibcode=2008BMCEE...8..220K }}</ref> The first [[Hominini|hominin]]s, the ancestors of humans, appeared near the end of the period.<ref name="homo-habilis"/><ref>{{cite web|url=https://phys.org/news/2017-05-scientists-million-year-old-pre-human-balkans.html|title=Scientists find 7.2-million-year-old pre-human remains in the Balkans|website=Phys.org|access-date=17 December 2017}}</ref>

About 20 Ma [[gymnosperm]]s in the form of some [[conifer]] and [[cycad]] groups started to diversify and produce more species due to the changing conditions.<ref>[https://www.floridamuseum.ufl.edu/science/gymnosperm-origin-evolution/ DNA duplication linked to the origin and evolution of pine trees and their relatives]</ref> In response to the cooler, seasonal climate, tropical plant species gave way to [[deciduous]] ones and grasslands replaced many forests. Grasses therefore greatly diversified, and herbivorous mammals evolved alongside it, creating the many grazing animals of today such as [[horse]]s, [[antelope]], and [[bison]]. Ice age mammals like the [[mammoth]]s and [[woolly rhinoceros]] were common in [[Pliocene]]. With lower levels of {{CO2}} in the atmosphere, [[List of C4 plants|{{C4}} plants]] expanded and reached ecological dominance in grasslands during the last 10 million years. Also [[Asteraceae]] (daisies) went through a significant [[adaptive radiation]].<ref>{{cite journal | doi=10.1038/s41467-021-27897-y | title=The rise of grasslands is linked to atmospheric CO2 decline in the late Palaeogene | year=2022 | last1=Palazzesi | first1=Luis | last2=Hidalgo | first2=Oriane | last3=Barreda | first3=Viviana D. | last4=Forest | first4=Félix | last5=Höhna | first5=Sebastian | journal=Nature Communications | volume=13 | issue=1 | page=293 | pmid=35022396 | pmc=8755714 | bibcode=2022NatCo..13..293P }}</ref> ''[[Eucalyptus]]'' fossil leaves occur in the [[Miocene]] of New Zealand, where the genus is not native today, but have been introduced from Australia.<ref>{{cite web|url=https://mikepole.wordpress.com/2014/09/22/eucalyptus-fossils-in-new-zealand-the-thin-end-of-the-wedge/|title=Eucalyptus fossils in New Zealand – the thin end of the wedge – Mike Pole|date=22 September 2014}}</ref>

==Disagreements==
The Neogene traditionally ended at the end of the Pliocene Epoch, just before the older definition of the beginning of the [[Quaternary]] Period; many time scales show this division.

However, there was a movement amongst geologists (particularly [[marine geologist]]s) to also include ongoing geological time (Quaternary) in the Neogene, while others (particularly terrestrial geologists) insist the Quaternary to be a separate period of distinctly different record. The somewhat confusing terminology and disagreement amongst geologists on where to draw what hierarchical boundaries is due to the comparatively fine divisibility of time units as time approaches the present, and due to geological preservation that causes the youngest sedimentary geological record to be preserved over a much larger area and to reflect many more environments than the older geological record.<ref name="tucker-2001">{{cite book |last1=Tucker |first1=M.E. |author-link1=Tucker, M. E. |title=Sedimentary petrology: an introduction to the origin of sedimentary rocks |date=2001 |publisher=Blackwell Science |location=Osney Nead, Oxford, UK |isbn=978-0-632-05735-1 |edition=3rd |language=en}}</ref> By dividing the [[Cenozoic]] Era into three (arguably two) periods ([[Paleogene]], Neogene, [[Quaternary]]) instead of seven epochs, the periods are more closely comparable to the duration of periods in the Mesozoic and Paleozoic Eras.

The [[International Commission on Stratigraphy]] (ICS) once proposed that the Quaternary be considered a sub-era (sub-erathem) of the Neogene, with a beginning date of 2.58 Ma, namely the start of the [[Gelasian|Gelasian Stage]].  In the 2004 proposal of the ICS, the Neogene would have consisted of the [[Miocene]] and  [[Pliocene]] Epochs.<ref>Lourens, L., Hilgen, F., Shackleton, N.J., Laskar, J., Wilson, D., (2004) "The Neogene Period". In: Gradstein, F., Ogg, J., Smith, A.G. (Eds.), ''Geologic Time Scale'', Cambridge University Press, Cambridge.</ref> The [[International Union for Quaternary Research]] (INQUA) counterproposed that the Neogene and the Pliocene end at 2.58 Ma, that the Gelasian be transferred to the Pleistocene, and the Quaternary be recognized as the third period in the Cenozoic, citing  key changes in Earth's climate, oceans, and biota that occurred 2.58 Ma and its correspondence to the [[Gauss-Matuyama reversal|Gauss-Matuyama magnetostratigraphic boundary]].<ref name="INQUA-16-1">[http://www.inqua.tcd.ie/documents/QP%2016-1.pdf Clague, John ''et al.''  (2006) "Open Letter by INQUA Executive Committee"] {{webarchive|url=https://web.archive.org/web/20060923053134/http://www.inqua.tcd.ie/documents/QP%2016-1.pdf |date=2006-09-23 }} ''Quaternary Perspective, the INQUA Newsletter'' International Union for Quaternary Research 16(1)</ref><ref>{{cite journal |last1=Clague |first1=John  |display-authors=etal|title=Open Letter by INQUA Executive Committee |journal=Quaternary Perspective, the INQUA Newsletter |date=2006 |volume=16 |issue=1 |url=http://www.inqua.tcd.ie/documents/QP%2016-1.pdf |access-date=2006-09-23 |doi=10.1016/j.quaint.2006.06.001|archive-url=https://web.archive.org/web/20060923053134/http://www.inqua.tcd.ie/documents/QP%2016-1.pdf |archive-date=2006-09-23|publisher=International Union for Quaternary Research|issn=1040-6182|pages=158–159}}</ref> In 2006 ICS and INQUA reached a compromise that made Quaternary a sub-era, subdividing Cenozoic into the old classical [[Tertiary (period)|Tertiary]] and Quaternary, a compromise that was rejected by [[International Union of Geological Sciences]] because it split both Neogene and Pliocene in two.<ref>{{cite web|url=http://www.stratigraphy.org/report06.pdf|title=ICS: Consolidated Annual Report for 2006|website=Stratigraphy.org|access-date=15 June 2007}}</ref>

Following formal discussions at the 2008 International Geological Congress in Oslo, Norway,<ref>{{cite web|url=http://www.33igc.org/coco/LayoutPage.aspx|title=Geoparks and Geotourism – Field Excursion of South America|website=33igc.org|access-date=17 December 2017}}</ref> the ICS decided in May 2009 to make the Quaternary the youngest period of the Cenozoic Era with its base at 2.58 Ma and including the Gelasian Age, which was formerly considered part of the Neogene Period and Pliocene Epoch.<ref name="ICS2009">{{cite web|url=http://www.quaternary.stratigraphy.org.uk/correlation/GSAchron09.jpg|title=See the 2009 version of the ICS geologic time scale|website=Quaternary.stratigraphy.org.uk|access-date=17 December 2017}}</ref> Thus the Neogene Period ends bounding the succeeding Quaternary Period at 2.58 Ma.

==References==
{{Reflist}}

==External links==
{{commons category}}
{{Wikisource portal|Cenozoic#Neogene}}
* {{cite web |title=Digital Atlas of Neogene Life for the Southeastern United States |url=http://geosun.sjsu.edu/~jhendricks/AtlasTemp/neogene.html |publisher=San Jose State University |access-date=21 September 2018 |archive-url=https://web.archive.org/web/20130423191403/http://geosun.sjsu.edu/~jhendricks/AtlasTemp/neogene.html |archive-date=2013-04-23}}

{{Neogene Footer}}
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[[Category:Neogene| ]]
[[Category:Geological periods]]