Editing Paleogene

{{Short description|First period of the Cenozoic Era}}
{{Distinguish|Paleocene}}
{{Infobox geologic timespan
| name                         = Paleogene
| color                        = Paleogene
| top_bar                      =
| time_start                   = 66.0
| time_end                     = 23.03
| image_map                    = Mollweide Paleographic Map of Earth, 45 Ma (Lutetian Age).png 
| caption_map                  = A map of Earth as it appeared 45 million years {{fact|date=January 2025}} ago during the Paleogene Period, Eocene Epoch
| image_outcrop                =
| caption_outcrop              =
| image_art                    =
| caption_art                  =
<!--Chronology-->
| timeline                     = Paleogene
<!--Etymology-->
| name_formality               = Formal
| name_accept_date             = 
| alternate_spellings          = Palaeogene, Palæogene
| synonym1                     =
| synonym1_coined              =
| synonym2                     =
| synonym2_coined              =
| synonym3                     =
| synonym3_coined              =
| nicknames                    =
| former_names                 =
| proposed_names               =
<!--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           = [[Iridium]] enriched layer associated with a major meteorite impact and subsequent [[K-Pg extinction event]].
| lower_gssp_location          = El Kef Section, [[El Kef]], [[Tunisia]]
| lower_gssp_coords            = {{Coord|36.1537|N|8.6486|E|display=inline}}
| lower_gssp_accept_date       = 1991<ref name="Molina 2006">{{cite journal|last1=Molina |first1=Eustoquio |last2=Alegret |first2=Laia |last3=Arenillas |first3=Ignacio |author4=José A. Arz |last5=Gallala |first5=Njoud |last6=Hardenbol |first6=Jan |author7=Katharina von Salis |last8=Steurbaut |first8=Etienne |last9=Vandenberghe |first9=Noel |author10=Dalila Zaghibib-Turki |title=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 |journal=Episodes |year=2006 |volume=29 |issue=4 |pages=263–278 |doi=10.18814/epiiugs/2006/v29i4/004 |doi-access=free }}</ref>
| upper_boundary_def           =
* Base of magnetic polarity [[chronozone]] C6Cn.2n.
* Near first appearance of the [[Foraminifera|Planktonic foraminiferan]] ''[[Paragloborotalia|Paragloborotalia kugleri]]''.
| upper_gssp_location          = Lemme-Carrosio Section, [[Carrosio]], [[Italy]]
| upper_gssp_coords            = {{Coord|44.6589|N|8.8364|E|display=inline}}
| upper_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>
<!--Atmospheric and Climatic Data-->
| o2                           = 26
| co2                          = 500
| temp                         = 18
| sea_level                    =
}}
The '''Paleogene Period''' ({{IPAc-en|ipa|ˈ|p|eɪ|l|i|.|ə|dʒ|iː|n|,_|-|l|i|.|oʊ|-|,_|ˈ|p|æ|l|i|-}} {{respell|PAY|lee|ə|jeen|,_|-|lee|oh|-|,_|PAL|ee|-}}; [[British English|also spelled]] '''Palaeogene''' or '''Palæogene''') is a [[geologic period|geologic period and system]] that spans 43 million years from the end of the [[Cretaceous]] Period {{period end|Cretaceous}} [[Megaannum|Ma]] (million years ago) to the beginning of the [[Neogene]] Period {{period start|neogene}} Ma. It is the first period of the [[Cenozoic]] [[Era]], the tenth period of the [[Phanerozoic]] and is divided into the [[Paleocene]], [[Eocene]], and [[Oligocene]] epochs. The earlier term [[Tertiary]] Period was used to define the time now covered by the Paleogene Period and subsequent Neogene Period; 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|access-date=2011-07-13|archive-date=2011-09-29|archive-url=https://web.archive.org/web/20110929004248/http://www.stratigraphy.org/bak/geowhen/TQ.html|url-status=live}}</ref> Paleogene is often abbreviated "Pg", although the [[United States Geological Survey]] uses the abbreviation "{{sc1|Pe}}" for the Paleogene on the Survey's geologic maps.<ref>{{cite web |last1=Federal Geographic Data Committee |title=FGDC Digital Cartographic Standard for Geologic Map Symbolization |url=https://ngmdb.usgs.gov/fgdc_gds/geolsymstd/fgdc-geolsym-sec32.pdf |website=The National Geologic Map Database |publisher=United States Geological Survey |access-date=29 January 2022}}</ref><ref>{{cite web |last1=Orndorff |first1=R.C. |title=Divisions of Geologic Time—Major Chronostratigraphic and Geochronologic Units |url=https://pubs.usgs.gov/fs/2007/3015/fs2007-3015.pdf |publisher=United States Geological Survey |access-date=29 January 2022 |date=20 July 2010}}</ref> 

Much of the world's modern vertebrate diversity originated in a rapid surge of diversification in the early Paleogene, as survivors of the [[Cretaceous–Paleogene extinction event]] took advantage of empty ecological niches left behind by the extinction of the non-avian dinosaurs, pterosaurs, marine reptiles, and primitive fish groups. [[evolution of mammals|Mammals continued to diversify]] from relatively small, simple forms into a highly diverse group ranging from small-bodied forms to very large ones, radiating into multiple [[Order (biology)|orders]] and colonizing the [[Bat|air]] and [[Marine mammal|marine ecosystems]] by the [[Eocene]].<ref>{{cite journal |last1=Meredith |first1=R. W. |last2=Janecka |first2=J. E. |last3=Gatesy |first3=J. |last4=Ryder |first4=O. A. |last5=Fisher |first5=C. A. |last6=Teeling |first6=E. C. |last7=Goodbla |first7=A. |last8=Eizirik |first8=E. |last9=Simao |first9=T. L. L. |last10=Stadler |first10=T. |last11=Rabosky |first11=D. L. |last12=Honeycutt |first12=R. L. |last13=Flynn |first13=J. J. |last14=Ingram |first14=C. M. |last15=Steiner |first15=C. |last16=Williams |first16=T. L. |last17=Robinson |first17=T. J. |last18=Burk-Herrick |first18=A. |last19=Westerman |first19=M. |last20=Ayoub |first20=N. A. |last21=Springer |first21=M. S. |last22=Murphy |first22=W. J. |title=Impacts of the Cretaceous Terrestrial Revolution and KPg Extinction on Mammal Diversification |journal=Science |date=28 October 2011 |volume=334 |issue=6055 |pages=521–524 |doi=10.1126/science.1211028|pmid=21940861 |bibcode=2011Sci...334..521M |s2cid=38120449 }}</ref> [[Bird|Birds]], the only surviving group of dinosaurs, [[Evolution of birds#Radiation of modern birds|quickly diversified]] from the very few [[Neognathae|neognath]] and [[Palaeognathae|paleognath]] clades that survived the extinction event, also radiating into multiple orders, colonizing different ecosystems and achieving an extreme level of morphological diversity.<ref>{{Cite journal |last1=Stiller |first1=Josefin |last2=Feng |first2=Shaohong |last3=Chowdhury |first3=Al-Aabid |last4=Rivas-González |first4=Iker |last5=Duchêne |first5=David A. |last6=Fang |first6=Qi |last7=Deng |first7=Yuan |last8=Kozlov |first8=Alexey |last9=Stamatakis |first9=Alexandros |last10=Claramunt |first10=Santiago |last11=Nguyen |first11=Jacqueline M. T. |last12=Ho |first12=Simon Y. W. |last13=Faircloth |first13=Brant C. |last14=Haag |first14=Julia |last15=Houde |first15=Peter |date=2024 |title=Complexity of avian evolution revealed by family-level genomes |journal=Nature |language=en |volume=629 |issue=8013 |pages=851–860 |doi=10.1038/s41586-024-07323-1 |pmid=38560995 |pmc=11111414 |bibcode=2024Natur.629..851S |issn=1476-4687}}</ref> [[Percomorpha|Percomorph]] fish, the most diverse group of vertebrates today, first appeared near the end of the Cretaceous but saw a very rapid radiation into their modern order and family-level diversity during the Paleogene, achieving a diverse array of morphologies.<ref>{{Cite journal |last1=Near |first1=Thomas J. |last2=Dornburg |first2=Alex |last3=Eytan |first3=Ron I. |last4=Keck |first4=Benjamin P. |last5=Smith |first5=W. Leo |last6=Kuhn |first6=Kristen L. |last7=Moore |first7=Jon A. |last8=Price |first8=Samantha A. |last9=Burbrink |first9=Frank T. |last10=Friedman |first10=Matt |last11=Wainwright |first11=Peter C. |date=2013-07-30 |title=Phylogeny and tempo of diversification in the superradiation of spiny-rayed fishes |journal=Proceedings of the National Academy of Sciences |language=en |volume=110 |issue=31 |pages=12738–12743 |doi=10.1073/pnas.1304661110 |doi-access=free |issn=0027-8424 |pmc=3732986 |pmid=23858462|bibcode=2013PNAS..11012738N }}</ref> 

The Paleogene is marked by considerable changes in climate from the [[Paleocene–Eocene Thermal Maximum]], through global cooling during the Eocene to the first appearance of permanent ice sheets in the Antarctic at the beginning of the Oligocene.<ref name="Scotese-2021" />

== Geology ==

=== Stratigraphy ===
The Paleogene is divided into three [[Series (stratigraphy)|series]]/[[Epoch|epochs]]: the Paleocene, Eocene, and Oligocene. These stratigraphic units can be defined globally or regionally. For global stratigraphic correlation, the [[International Commission on Stratigraphy]] (ICS) ratify global [[Stage (stratigraphy)|stages]] based on a [[Global Boundary Stratotype Section and Point]] (GSSP) from a single [[Geological formation|formation]] (a [[stratotype]]) identifying the lower boundary of the stage.<ref>{{Cite web |title=International Commission on Stratigraphy |url=https://stratigraphy.org/chart |access-date=2024-07-15 |website=stratigraphy.org |archive-date=2014-05-30 |archive-url=https://web.archive.org/web/20140530005940/http://www.stratigraphy.org/index.php/ics-chart-timescale |url-status=live }}</ref>

==== Paleocene ====
The Paleocene is the first series/epoch of the Paleogene and lasted from 66.0 Ma to 56.0 Ma. It is divided into three stages: the [[Danian]] 66.0 - 61.6 Ma; [[Selandian]] 61.6 - 59.2 Ma; and, [[Thanetian]] 59.2 - 56.0 Ma.<ref name=":0">{{Citation |last1=Vandenberghe |first1=N. |title=Chapter 28 - The Paleogene Period |date=2012-01-01 |work=The Geologic Time Scale |pages=855–921 |editor-last=Gradstein |editor-first=Felix M. |url=https://www.sciencedirect.com/science/article/pii/B9780444594259000287 |access-date=2024-07-15 |place=Boston |publisher=Elsevier |isbn=978-0-444-59425-9 |last2=Hilgen |first2=F. J. |last3=Speijer |first3=R. P. |last4=Ogg |first4=J. G. |last5=Gradstein |first5=F. M. |last6=Hammer |first6=O. |last7=Hollis |first7=C. J. |last8=Hooker |first8=J. J. |editor2-last=Ogg |editor2-first=James G. |editor3-last=Schmitz |editor3-first=Mark D. |editor4-last=Ogg |editor4-first=Gabi M. |archive-date=2015-09-24 |archive-url=https://web.archive.org/web/20150924145807/http://www.sciencedirect.com/science/article/pii/B9780444594259000287 |url-status=live }}</ref> The GSSP for the base of the Cenozoic, Paleogene and Paleocene is at Oued Djerfane, west of [[El Kef]], [[Tunisia]]. It is marked by an [[iridium anomaly]] produced by an [[asteroid]] impact, and is associated with the Cretaceous–Paleogene extinction event. The boundary is defined as the rusty colored base of a 50 cm thick [[clay]], which would have been deposited over only a few days. Similar layers are seen in marine and continental deposits worldwide. These layers include the iridium anomaly, [[Tektite|microtektites]], [[nickel]]-rich [[spinel]] crystals and [[shocked quartz]], all indicators of a major extraterrestrial impact. The remains of the crater are found at [[Chicxulub crater|Chicxulub]] on the [[Yucatan Peninsula]] in [[Mexico]]. The extinction of the [[Dinosaur|non-avian dinosaurs]], [[Ammonoidea|ammonites]] and dramatic changes in [[Plankton|marine plankton]] and many other groups of organisms, are also used for correlation purposes.<ref name=":0" />

==== Eocene ====
The Eocene is the second series/epoch of the Paleogene, and lasted from 56.0 Ma to 33.9 Ma. It is divided into four stages: the [[Ypresian]] 56.0 Ma to 47.8 Ma; [[Lutetian]] 47.8 Ma to 41.2 Ma; [[Bartonian]] 41.2 Ma to 37.71 Ma; and, [[Priabonian]] 37.71 Ma to 33.9 Ma. The GSSP for the base of the Eocene is at Dababiya, near [[Luxor]], [[Egypt]] and is marked by the start of a significant variation in global [[Isotopes of carbon|carbon isotope]] ratios, produced by a major period of global warming. The change in climate was due to a rapid release of frozen [[Methane clathrate|methane clathrates]] from seafloor sediments at the beginning of the Paleocene-Eocene thermal maximum (PETM).<ref name=":0" />

==== Oligocene ====
The Oligocene is the third and youngest series/epoch of the Paleogene, and lasted from 33.9 Ma to 23.03 Ma. It is divided into two stages: the [[Rupelian]] 33.9 Ma to 27.82 Ma; and, [[Chattian]] 27.82 - 23.03 Ma. The GSSP for the base of the Oligocene is at [[Massignano]], near [[Ancona]], [[Italy]]. The extinction the ''[[Hantkeninoidea|hantkeninid]]'' planktonic [[foraminifera]] is the key marker for the Eocene-Oligocene boundary, which was a time of climate cooling that led to widespread changes in fauna and flora.<ref name=":0" />

== Palaeogeography ==
The final stages of the breakup of [[Pangaea]] occurred during the Paleogene as [[Atlantic Ocean]] [[Rift|rifting]] and [[seafloor spreading]] extended northwards, separating the [[North American plate|North America]] and [[Eurasian plate|Eurasian]] plates, and [[Australian plate|Australia]] and [[South American plate|South America]] rifted from [[Antarctic plate|Antarctica]], opening the [[Southern Ocean]]. [[African plate|Africa]] and [[Indian plate|India]] collided with Eurasia forming the [[Alpide belt|Alpine-Himalayan]] mountain chains and the western margin of the [[Pacific plate]] changed from a [[Divergent boundary|divergent]] to [[Convergent boundary|convergent]] plate boundary.<ref name=":1">{{Cite book |last1=Torsvik |first1=Trond H. |title=Earth history and palaeogeography |last2=Cocks |first2=Leonard Robert Morrison |date=2017 |publisher=Cambridge university press |isbn=978-1-107-10532-4 |location=Cambridge}}</ref>

=== Alpine–Himalayan orogeny ===

==== Alpine orogeny ====
The [[Alpine orogeny]] developed in response to the collision between the African and Eurasian plates during the closing of the [[Tethys Ocean|Neotethys Ocean]] and the opening of the Central Atlantic Ocean. The result was a series of arcuate mountain ranges, from the [[Tell Atlas|Tell]]-[[Rif]]-[[Baetic System|Betic]] cordillera in the western [[Mediterranean Sea|Mediterranean]] through the [[Alps]], [[Carpathian Mountains|Carpathians]], [[Apennine Mountains|Apennines]], [[Dinaric Alps|Dinarides]] and [[Pindus|Hellenides]] to the [[Taurus Mountains|Taurides]] in the east.<ref name=":2">{{Cite journal |last1=Royden |first1=Leigh |last2=Faccenna |first2=Claudio |date=2018-05-30 |title=Subduction Orogeny and the Late Cenozoic Evolution of the Mediterranean Arcs |url=https://www.annualreviews.org/doi/10.1146/annurev-earth-060115-012419 |journal=Annual Review of Earth and Planetary Sciences |language=en |volume=46 |issue=1 |pages=261–289 |doi=10.1146/annurev-earth-060115-012419 |bibcode=2018AREPS..46..261R |issn=0084-6597}}</ref><ref name=":1" />

From the Late Cretaceous into the early Paleocene, Africa began to converge with Eurasia. The irregular outlines of the continental margins, including the [[Adriatic plate|Adriatic promontory (Adria)]] that extended north from the African plate, led to the development of several short [[subduction]] zones, rather than one long system.<ref name=":2" /> In the western Mediterranean, the European plate was subducted southwards beneath the African plate, whilst in the eastern Mediterranean, Africa was subducted beneath Eurasia along a northward dipping subduction zone.<ref name=":1" /><ref name=":3">{{Cite journal |last1=Martín-Martín |first1=Manuel |last2=Perri |first2=Francesco |last3=Critelli |first3=Salvatore |date=2023-08-01 |title=Cenozoic detrital suites from the Internal Betic-Rif Cordilleras (S Spain and N Morocco): implications for paleogeography and paleotectonics |url=https://www.sciencedirect.com/science/article/pii/S0012825223001873#s0085 |journal=Earth-Science Reviews |volume=243 |pages=104498 |doi=10.1016/j.earscirev.2023.104498 |bibcode=2023ESRv..24304498M |issn=0012-8252|hdl=10045/136199 |hdl-access=free }}</ref> Convergence between the [[Iberian plate|Iberian]] and European plates led to the [[Pyrenees|Pyrenean orogeny]]<ref name=":4">{{Cite journal |last1=Brunsmann |first1=Quentin |last2=Rosenberg |first2=Claudio Luca |last3=Bellahsen |first3=Nicolas |date=2024 |title=The Western Alpine arc: a review and new kinematic model |journal=Comptes Rendus. Géoscience |language=fr |volume=356 |issue=S2 |pages=231–263 |doi=10.5802/crgeos.253 |issn=1778-7025|doi-access=free }}</ref> and, as Adria pushed northwards the Alps and Carpathian orogens began to develop.<ref name=":5">{{Cite journal |last1=Stephenson |first1=Randell |last2=Schiffer |first2=Christian |last3=Peace |first3=Alexander |last4=Nielsen |first4=Søren Bom |last5=Jess |first5=Scott |date=2020-11-01 |title=Late Cretaceous-Cenozoic basin inversion and palaeostress fields in the North Atlantic-western Alpine-Tethys realm: Implications for intraplate tectonics |url=https://www.sciencedirect.com/science/article/abs/pii/S0012825220302981 |journal=Earth-Science Reviews |volume=210 |pages=103252 |doi=10.1016/j.earscirev.2020.103252 |bibcode=2020ESRv..21003252S |hdl=2164/16706 |issn=0012-8252|hdl-access=free }}</ref><ref name=":3" />

[[File:Tectonic map Mediterranean EN.svg|alt=Map shows the location of subduction zones and extensional features of the western Alpine-Himalayan orogenic belt.|thumb|Present day tectonic map of southern Europe, North Africa and the Middle East, showing structures of the western Alpine-Himalayan orogenic belt. ]]

The collision of Adria with Eurasia in the early Palaeocene was followed by a c.10 million year pause in the convergence of Africa and Eurasia, connected with the onset of the opening of the North Atlantic Ocean as [[Greenland plate|Greenland]] rifted from the Eurasian plate in the Palaeocene.<ref name=":5" /> Convergence rates between Africa and Eurasia increased again in the early Eocene and the remaining oceanic basins between Adria and Europe closed.<ref name=":2" /><ref>{{Cite journal |last1=Brombin |first1=Valentina |last2=Bonadiman |first2=Costanza |last3=Jourdan |first3=Fred |last4=Roghi |first4=Guido |last5=Coltorti |first5=Massimo |last6=Webb |first6=Laura E. |last7=Callegaro |first7=Sara |last8=Bellieni |first8=Giuliano |last9=De Vecchi |first9=Giampaolo |last10=Sedea |first10=Roberto |last11=Marzoli |first11=Andrea |date=2019-05-01 |title=Intraplate magmatism at a convergent plate boundary: The case of the Cenozoic northern Adria magmatism |url=https://www.sciencedirect.com/science/article/abs/pii/S0012825218305440 |journal=Earth-Science Reviews |volume=192 |pages=355–378 |doi=10.1016/j.earscirev.2019.03.016 |bibcode=2019ESRv..192..355B |hdl=11392/2403525 |issn=0012-8252 |hdl-access=free |access-date=2024-08-19 |archive-date=2024-04-17 |archive-url=https://web.archive.org/web/20240417162108/https://www.sciencedirect.com/science/article/abs/pii/S0012825218305440 |url-status=live }}</ref>

Between about 40 and 30 Ma, subduction began along the western Mediterranean arc of the Tell, Rif, Betic and Apennine mountain chains. The rate of convergence was less than the subduction rate of the dense [[lithosphere]] of the western Mediterranean and [[Subduction|roll-back]] of the subducting slab led to the arcuate structure of these mountain ranges.<ref name=":2" /><ref name=":4" />

In the eastern Mediterranean, c. 35 Ma, the Anatolide-Tauride platform (northern part of Adria) began to enter the [[Subduction|trench]] leading to the development of the Dinarides, Hellenides and Tauride mountain chains as the [[passive margin]] [[Sediment|sediments]] of Adria were scrapped off onto the Eurasia [[Crust (geology)|crust]] during subduction.<ref name=":2" /><ref>{{Cite journal |last1=Schmid |first1=Stefan M. |last2=Fügenschuh |first2=Bernhard |last3=Kounov |first3=Alexandre |last4=Maţenco |first4=Liviu |last5=Nievergelt |first5=Peter |last6=Oberhänsli |first6=Roland |last7=Pleuger |first7=Jan |last8=Schefer |first8=Senecio |last9=Schuster |first9=Ralf |last10=Tomljenović |first10=Bruno |last11=Ustaszewski |first11=Kamil |last12=van Hinsbergen |first12=Douwe J. J. |date=2020-02-01 |title=Tectonic units of the Alpine collision zone between Eastern Alps and western Turkey |url=https://www.sciencedirect.com/science/article/abs/pii/S1342937X19302199 |journal=Gondwana Research |volume=78 |pages=308–374 |doi=10.1016/j.gr.2019.07.005 |bibcode=2020GondR..78..308S |hdl=1874/394073 |issn=1342-937X |hdl-access=free |access-date=2024-08-19 |archive-date=2024-04-14 |archive-url=https://web.archive.org/web/20240414212948/https://www.sciencedirect.com/science/article/abs/pii/S1342937X19302199 |url-status=live }}</ref>

==== Zagros Mountains ====
The [[Zagros Mountains|Zagros mountain]] belt stretches for c. 2000 km from the eastern border of [[Iraq]] to the [[Makran]] coast in southern [[Iran]]. It formed as a result of the convergence and collision of the [[Arabian plate|Arabian]] and Eurasian plates as the Neotethys Ocean closed and is composed sediments scrapped from the descending Arabian Plate.<ref name=":6">{{Cite journal |last1=Koshnaw |first1=Renas I. |last2=Schlunegger |first2=Fritz |last3=Stockli |first3=Daniel F. |date=2021-11-03 |title=Detrital zircon provenance record of the Zagros mountain building from the Neotethys obduction to the Arabia–Eurasia collision, NW Zagros fold–thrust belt, Kurdistan region of Iraq |url=https://se.copernicus.org/articles/12/2479/2021/#section6 |journal=Solid Earth |language=English |volume=12 |issue=11 |pages=2479–2501 |doi=10.5194/se-12-2479-2021 |doi-access=free |bibcode=2021SolE...12.2479K |issn=1869-9510 |access-date=2024-08-19 |archive-date=2024-08-19 |archive-url=https://web.archive.org/web/20240819143651/https://se.copernicus.org/articles/12/2479/2021/#section6 |url-status=live }}</ref><ref name=":7">{{Cite journal |last1=Fu |first1=Xiaofei |last2=Feng |first2=Zhiqiang |last3=Zhang |first3=Faqiang |last4=Zhang |first4=Zhongmin |last5=Guo |first5=Jinrui |last6=Cao |first6=Zhe |last7=Kor |first7=Ting |last8=Cheng |first8=Ming |last9=Yan |first9=Jianzhao |last10=Zhou |first10=Yu |date=2024-03-01 |title=Wilson cycles of the Zagros fold and thrust belt: A comprehensive review |url=https://www.sciencedirect.com/science/article/abs/pii/S1367912023004546 |journal=Journal of Asian Earth Sciences |volume=262 |pages=105993 |doi=10.1016/j.jseaes.2023.105993 |bibcode=2024JAESc.26205993F |issn=1367-9120}}</ref>

From the Late Cretaceous, a [[volcanic arc]] developed on the Eurasia margin as the Neotethys crust was subducted beneath it. A separate intra-oceanic subduction zone in the Neotethys resulted in the [[Obduction|obuction]] of ocean crust onto the Arabian margin in the Late Cretaceous to Paleocene, with break-off of the subducted oceanic plate close to the Arabian margin occurring during the Eocene.<ref name=":6" /><ref name=":7" /> Continental collision began during the Eocene c. 35 Ma and continued into the Oligocene to c. 26 Ma.<ref name=":6" /><ref name=":7" />

==== Himalayan orogeny ====
[[File:India 71-0 Ma.gif|alt=Map showing the outline of the Indian continent as it drifted north from close to Madagascar to its present day position. |thumb|Map showing the northwards drift of the Indian continent between 71 and 0 Ma. The leading edge of Greater India (not shown on the map) collided with the Eurasian plate c. 55 Ma, whilst India itself still lay to the south. (From: Dèzes, 1999)]]
The Indian continent rifted from [[Madagascar]] at c. 83 Ma and drifted rapidly (c. 18 cm/yr in the Paleocene) northwards towards the southern margin of Eurasia. A rapid decrease in velocity to c. 5 cm/yr in the early Eocene records the collision of the Tethyan (Tibetan) [[Himalayas]], the leading edge of Greater India, with the [[Lhasa terrane]] of [[Tibet]] (southern Eurasian margin), along the [[Indus-Yarlung suture zone|Indus-Yarling-Zangbo suture zone]].<ref name=":1" /><ref>{{Cite journal |last=Metcalfe |first=Ian |date=2021-12-01 |title=Multiple Tethyan ocean basins and orogenic belts in Asia |url=https://www.sciencedirect.com/science/article/abs/pii/S1342937X21000307 |journal=Gondwana Research |series=SPECIAL ISSUE: GR-100 |volume=100 |pages=87–130 |doi=10.1016/j.gr.2021.01.012 |bibcode=2021GondR.100...87M |issn=1342-937X}}</ref> To the south of this zone, the Himalaya are composed of [[Metasedimentary rock|metasedimentary]] rocks scraped off the now subducted Indian continental crust and [[Mantle (geology)|mantle]] lithosphere as the collision progressed.<ref name=":1" />

[[Paleomagnetism|Palaeomagnetic]] data place the present day Indian continent further south at the time of collision and decrease in plate velocity, indicating the presence of a large region to the north of India that has now been subducted beneath the Eurasian plate or incorporated into the mountain belt. This region, known as Greater India, formed by [[Extensional tectonics|extension]] along the northern margin of India during the opening of the Neotethys. The Tethyan Himalaya block lay along its northern edge, with the Neotethys Ocean lying between it and southern Eurasia.<ref name=":1" /><ref name=":8">{{Cite journal |last1=Martin |first1=Craig R. |last2=Jagoutz |first2=Oliver |last3=Upadhyay |first3=Rajeev |last4=Royden |first4=Leigh H. |last5=Eddy |first5=Michael P. |last6=Bailey |first6=Elizabeth |last7=Nichols |first7=Claire I. O. |last8=Weiss |first8=Benjamin P. |date=2020-11-24 |title=Paleocene latitude of the Kohistan–Ladakh arc indicates multistage India–Eurasia collision |journal=Proceedings of the National Academy of Sciences |language=en |volume=117 |issue=47 |pages=29487–29494 |doi=10.1073/pnas.2009039117 |doi-access=free |issn=0027-8424 |pmc=7703637 |pmid=33148806|bibcode=2020PNAS..11729487M }}</ref>

Debate about the amount of deformation seen in the geological record in the India–Eurasia collision zone versus the size of Greater India, the timing and nature of the collision relative to the decrease in plate velocity, and explanations for the unusually high velocity of the Indian plate have led to several models for Greater India: 1) A Late Cretaceous to early Paleocene subduction zone may have lain between India and Eurasia in the Neotethys, dividing the region into two plates, subduction was followed by collision of India with Eurasia in the middle Eocene. In this model Greater India would have been less than 900 km wide;<ref name=":8" /> 2) Greater India may have formed a single plate, several thousand kilometres wide, with the Tethyan Himalaya microcontinent separated from the Indian continent by an [[oceanic basin]]. The microcontinent collided with southern Eurasia c. 58 Ma (late Paleocene), whilst the velocity of the plate did not decrease until c. 50 Ma when subduction rates dropped as young, oceanic crust entered the subduction zone;<ref>{{Cite journal |last1=van Hinsbergen |first1=Douwe J. J. |last2=Lippert |first2=Peter C. |last3=Li |first3=Shihu |last4=Huang |first4=Wentao |last5=Advokaat |first5=Eldert L. |last6=Spakman |first6=Wim |date=2019-06-05 |title=Reconstructing Greater India: Paleogeographic, kinematic, and geodynamic perspectives |url=https://www.sciencedirect.com/science/article/abs/pii/S0040195118301331 |journal=Tectonophysics |series=Linking Plate Tectonics and Volcanism to Deep Earth Dynamics – a tribute to Trond H. Torsvik |volume=760 |pages=69–94 |doi=10.1016/j.tecto.2018.04.006 |bibcode=2019Tectp.760...69V |hdl=1874/380963 |issn=0040-1951 |hdl-access=free |access-date=2024-08-19 |archive-date=2024-04-15 |archive-url=https://web.archive.org/web/20240415030023/https://www.sciencedirect.com/science/article/abs/pii/S0040195118301331 |url-status=live }}</ref> 3) This model assigns older dates to parts of Greater India, which changes its paleogeographic position relative to Eurasia and creates a Greater India formed of extended continental crust 2000–3000 km wide.<ref>{{Cite journal |last1=Meng |first1=Jun |last2=Gilder |first2=Stuart A. |last3=Tan |first3=Xiaodong |last4=Li |first4=Xin |last5=Li |first5=Yalin |last6=Luo |first6=Hui |last7=Suzuki |first7=Noritoshi |last8=Wang |first8=Zihao |last9=Chi |first9=Yuchen |last10=Zhang |first10=Chunyang |last11=Wang |first11=Chengshan |date=2023-08-15 |title=Strengthening the argument for a large Greater India |journal=Proceedings of the National Academy of Sciences |language=en |volume=120 |issue=33 |pages=e2305928120 |doi=10.1073/pnas.2305928120 |issn=0027-8424 |pmc=10433724 |pmid=37552758|bibcode=2023PNAS..12005928M }}</ref>

==== South East Asia ====
The Alpine-Himalayan Orogenic Belt in [[Southeast Asia]] extends from the Himalayas in India through [[Myanmar]] ([[Burma terrane|West Burma block]]) [[Sumatra]], [[Java]] to [[West Sulawesi]].<ref name=":9">{{Cite journal |last=Metcalfe |first=Ian |date=2021-12-01 |title=Multiple Tethyan ocean basins and orogenic belts in Asia |url=https://www.sciencedirect.com/science/article/abs/pii/S1342937X21000307 |journal=Gondwana Research |series=SPECIAL ISSUE: GR-100 |volume=100 |pages=87–130 |doi=10.1016/j.gr.2021.01.012 |bibcode=2021GondR.100...87M |issn=1342-937X |access-date=2024-08-19 |archive-date=2024-04-18 |archive-url=https://web.archive.org/web/20240418160526/https://www.sciencedirect.com/science/article/abs/pii/S1342937X21000307 |url-status=live }}</ref>

During the Late Cretaceous to Paleogene, the northward movement of the Indian plate led to the highly oblique subduction of the Neotethys along the edge of the West Burma block and the development of a major north-south [[transform fault]] along the margin of Southeast Asia to the south.<ref name=":10">{{Cite journal |last=Morley |first=C. K. |date=2012-10-01 |title=Late Cretaceous–Early Palaeogene tectonic development of SE Asia |url=https://www.sciencedirect.com/science/article/abs/pii/S0012825212000992 |journal=Earth-Science Reviews |volume=115 |issue=1 |pages=37–75 |doi=10.1016/j.earscirev.2012.08.002 |bibcode=2012ESRv..115...37M |issn=0012-8252}}</ref><ref name=":9" /> Between c. 60 and 50 Ma, the leading northeastern edge of Greater India collided with the West Burma block resulting in [[Deformation (geology)|deformation]] and [[metamorphism]].<ref name=":10" /> During the middle Eocene, north-dipping subduction resumed along the southern edge of Southeast Asia, from west Sumatra to West Sulawesi, as the Australian plate drifted slowly northwards.<ref name=":9" />

Collision between India and the West Burma block was complete by the late Oligocene. As the India-Eurasia collision continued, movement of material away from the collision zone was accommodated along, and extended, the already existing major [[Strike-slip tectonics|strike slip]] systems of the region.<ref name=":10" />

=== Atlantic Ocean ===
During the Paleocene, seafloor spreading along the [[Mid-Atlantic Ridge]] propagated from the Central Atlantic northwards between North America and Greenland in the [[Labrador Sea]] (c. 62 Ma) and [[Baffin Bay]] (c. 57 Ma), and, by the early Eocene (c. 54 Ma), into the northeastern Atlantic between Greenland and Eurasia.<ref name=":1" /><ref>{{Cite journal |last1=Gaina |first1=Carmen |last2=Jakob |first2=Johannes |date=2019-06-05 |title=Global Eocene tectonic unrest: Possible causes and effects around the North American plate |url=https://www.sciencedirect.com/science/article/abs/pii/S0040195118302889 |journal=Tectonophysics |series=Linking Plate Tectonics and Volcanism to Deep Earth Dynamics – a tribute to Trond H. Torsvik |volume=760 |pages=136–151 |doi=10.1016/j.tecto.2018.08.010 |bibcode=2019Tectp.760..136G |issn=0040-1951 |access-date=2024-08-19 |archive-date=2024-04-15 |archive-url=https://web.archive.org/web/20240415181135/https://www.sciencedirect.com/science/article/abs/pii/S0040195118302889 |url-status=live }}</ref> Extension between North America and Eurasia, also in the early Eocene, led to the opening of the Eurasian Basin across the Arctic, which was linked to the Baffin Bay Ridge and Mid-Atlantic Ridge to the south via major strike slip faults.<ref name=":1" /><ref name=":11">{{Cite journal |last1=Abdelmalak |first1=M. M. |last2=Planke |first2=S. |last3=Polteau |first3=S. |last4=Hartz |first4=E. H. |last5=Faleide |first5=J. I. |last6=Tegner |first6=C. |last7=Jerram |first7=D. A. |last8=Millett |first8=J. M. |last9=Myklebust |first9=R. |date=2019-06-05 |title=Breakup volcanism and plate tectonics in the NW Atlantic |url=https://www.sciencedirect.com/science/article/abs/pii/S0040195118302816 |journal=Tectonophysics |series=Linking Plate Tectonics and Volcanism to Deep Earth Dynamics – a tribute to Trond H. Torsvik |volume=760 |pages=267–296 |doi=10.1016/j.tecto.2018.08.002 |bibcode=2019Tectp.760..267A |hdl=2164/12816 |issn=0040-1951|hdl-access=free }}</ref>

From the Eocene and into the early Oligocene, Greenland acted as an independent plate moving northwards and rotating anticlockwise. This led to compression across the [[Arctic Archipelago|Canadian Arctic Archipelago]], [[Svalbard]] and northern Greenland resulting in the [[Eurekan orogeny|Eureka orogeny]].<ref name=":1" /><ref name=":11" /> From c. 47 Ma, the eastern margin of Greenland was cut by the Reykjanes Ridge (the northeastern branch of the Mid-Atlantic Ridge) propagating northwards and splitting off the [[Jan Mayen Microcontinent|Jan Mayen microcontinent]].<ref name=":1" />

After c. 33 Ma seafloor spreading in Labrador Sea and Baffin Bay gradually ceased and seafloor spreading focused along the northeast Atlantic. By the late Oligocene, the plate boundary between North America and Eurasia was established along the Mid-Atlantic Ridge, with Greenland attached to the North American plate again, and the Jan Mayen microcontinent part of the Eurasian plate, where its remains now lie to the east and possibly beneath the southeast of Iceland.<ref name=":1" /><ref name=":11" />

==== North Atlantic Large Igneous Province ====
[[File:Basalt columns on Staffa - geograph.org.uk - 906889.jpg|thumb|A Paleogene-aged basaltic lava flow on the Isle of [[Staffa]], Scotland (person standing on cliff top for scale). The bottom section of this cliff is [[volcaniclastic rock]]. The middle and top sections are two parts of a single basaltic lava flow; each part of the lava flow cooled differently, forming rock with different characteristics. The middle layer shows spectacular [[columnar jointing]] resulting from relatively slow cooling; the top layer has very irregular closely-spaced joints caused by more rapid cooling.<ref name="Upton2015">{{cite book | title="Volcanoes and the Making of Scotland" |edition=2nd | publisher=Dunedin Academic Press | last=Upton | first=Brian | year=2015 | location=Edinburgh | isbn=9781780465418}}</ref>|alt=Cliff face showing three layers of rock; the bottom layer is sedimentary rock; the middle layer forms columns, whilst the layer above is blocky in appearance.]]

The [[North Atlantic Igneous Province]] stretches across the Greenland and northwest European margins and is associated with the proto-Icelandic [[mantle plume]], which rose beneath the Greenland lithosphere at c. 65 Ma.<ref name=":11" /> There were two main phases of volcanic activity with peaks at c. 60 Ma and c. 55 Ma. [[Magmatism]] in the British and Northwest Atlantic volcanic provinces occurred mainly in the early Palaeocene, the latter associated with an increased spreading rate in the Labrador Sea, whilst northeast Atlantic magmatism occurred mainly during the early Eocene and is associated with a change in the spreading direction in the Labrador Sea and the northward drift of Greenland. The locations of the magmatism coincide with the intersection of propagating the rifts and large-scale, pre-existing lithospheric structures, which acted as channels to the surface for the [[magma]].<ref name=":11" /><ref name=":12">{{Cite journal |last1=Peace |first1=Alexander L. |last2=Phethean |first2=J. J. J. |last3=Franke |first3=D. |last4=Foulger |first4=G. R. |last5=Schiffer |first5=C. |last6=Welford |first6=J. K. |last7=McHone |first7=G. |last8=Rocchi |first8=S. |last9=Schnabel |first9=M. |last10=Doré |first10=A. G. |date=2020-07-01 |title=A review of Pangaea dispersal and Large Igneous Provinces – In search of a causative mechanism |url=https://www.sciencedirect.com/science/article/abs/pii/S0012825219304817 |journal=Earth-Science Reviews |series=A new paradigm for the North Atlantic Realm |volume=206 |pages=102902 |doi=10.1016/j.earscirev.2019.102902 |bibcode=2020ESRv..20602902P |hdl=11568/992336 |issn=0012-8252|hdl-access=free }}</ref>

The arrival of the proto-Iceland plume has been considered the driving mechanism for rifting in the North Atlantic. However, that rifting and initial seafloor spreading occurred prior to the arrival of the plume, large scale magmatism occurred at a distance to rifting, and that rifting propagated towards, rather than away from the plume, has led to the suggestion the plume and associated magmatism may have been a result, rather than a cause, of the plate tectonic forces that led to the propagation of rifting from the Central to the North Atlantic.<ref name=":11" /><ref name=":12" />

=== Americas ===

==== North America ====
Mountain building continued along the [[North American Cordillera|North America Cordillera]] in response to subduction of the [[Farallon plate]] beneath the North American Plate. Along the central section of the North American margin, crustal shortening of the Cretaceous to Paleocene [[Sevier orogeny|Sevier orogen]] lessened and deformation moved eastward. The decreasing dip of the subducting Farallon plate led to a [[Flat slab subduction|flat-slab]] segment that increased friction between this and the base of the North American Plate. The resulting [[Laramide orogeny]], which began the development of the [[Rocky Mountains]], was a broad zone of [[thick-skinned deformation]], with [[Fault (geology)|faults]] extending to mid-crustal depths and the uplift of [[Basement (geology)|basement rocks]] that lay to the east of the Sevier belt, and more than 700km from the trench.<ref name=":13">{{Cite book |last1=Stanley |first1=Steven |title=Earth System Science |last2=Luczaj |first2=John |publisher=W.H.Freeman and Company |year=2015 |isbn=978-1-319-15402-8 |edition=4th |location=New York}}</ref><ref name=":14">{{Cite journal |last1=Yonkee |first1=W. A. |last2=Weil |first2=A. B. |last3=Wells |first3=M. L. |date=2024-07-01 |title=Integrating structural, paleomagnetic, and thermo/geochronologic studies to understand evolution of the Sevier and Laramide belts, northern Utah to Wyoming |journal=Journal of Structural Geology |volume=184 |pages=105104 |doi=10.1016/j.jsg.2024.105104 |bibcode=2024JSG...18405104Y |issn=0191-8141|doi-access=free }}</ref> With the Laramide uplift the [[Western Interior Seaway]] was divided and then retreated.<ref name=":13" />

During the mid to late Eocene (50–35 Ma), plate convergence rates decreased and the dip of the Farallon slab began to steepen. Uplift ceased and the region largely levelled by [[erosion]]. By the Oligocene, convergence gave way to extension, rifting and widespread volcanism across the Laramide belt.<ref name=":13" /><ref name=":14" />

==== South America ====
Ocean-continent convergence accommodated by east dipping subduction zone of the Farallon plate beneath the western edge of South America continued from the Mesozoic.<ref name=":15">{{Cite journal |last=Horton |first=Brian K. |date=February 2018 |title=Tectonic Regimes of the Central and Southern Andes: Responses to Variations in plate Coupling During Subduction |url=https://agupubs.onlinelibrary.wiley.com/doi/10.1002/2017TC004624 |journal=Tectonics |language=en |volume=37 |issue=2 |pages=402–429 |doi=10.1002/2017TC004624 |bibcode=2018Tecto..37..402H |issn=0278-7407}}</ref>

Over the Paleogene, changes in plate motion and episodes of regional slab shallowing and steepening resulted in variations in the magnitude of crustal shortening and amounts of magmatism along the length of the [[Andes]].<ref name=":15" /> In the Northern Andes, an [[oceanic plateau]] with volcanic arc was accreted during the latest Cretaceous and Paleocene, whilst the Central Andes were dominated by the subduction of oceanic crust and the Southern Andes were impacted by the subduction of the Farallon-East Antarctic ocean ridge.<ref>{{Cite journal |last1=Pfiffner |first1=O. Adrian |last2=Gonzalez |first2=Laura |date=June 2013 |title=Mesozoic–Cenozoic Evolution of the Western Margin of South America: Case Study of the Peruvian Andes |journal=Geosciences |language=en |volume=3 |issue=2 |pages=262–310 |doi=10.3390/geosciences3020262 |doi-access=free |bibcode=2013Geosc...3..262P |issn=2076-3263}}</ref><ref name=":16">{{Cite journal |last1=Seton |first1=M. |last2=Müller |first2=R. D. |last3=Zahirovic |first3=S. |last4=Gaina |first4=C. |last5=Torsvik |first5=T. |last6=Shephard |first6=G. |last7=Talsma |first7=A. |last8=Gurnis |first8=M. |last9=Turner |first9=M. |last10=Maus |first10=S. |last11=Chandler |first11=M. |date=2012-07-01 |title=Global continental and ocean basin reconstructions since 200 Ma |url=https://www.sciencedirect.com/science/article/abs/pii/S0012825212000311 |journal=Earth-Science Reviews |volume=113 |issue=3 |pages=212–270 |doi=10.1016/j.earscirev.2012.03.002 |bibcode=2012ESRv..113..212S |issn=0012-8252}}</ref>

==== Caribbean ====
The [[Caribbean plate]] is largely composed of oceanic crust of the [[Caribbean large igneous province|Caribbean Large Igneous Province]] that formed during the Late Cretaceous.<ref name=":16" /> During the Late Cretaceous to Paleocene, subduction of Atlantic crust was established along its northern margin, whilst to the southwest, an island arc collided with the northern Andes forming an east dipping subduction zone where Caribbean lithosphere was subducted beneath the South American margin.<ref name=":17">{{Cite journal |last1=Montes |first1=Camilo |last2=Rodriguez-Corcho |first2=Andres Felipe |last3=Bayona |first3=German |last4=Hoyos |first4=Natalia |last5=Zapata |first5=Sebastian |last6=Cardona |first6=Agustin |date=2019-11-01 |title=Continental margin response to multiple arc-continent collisions: The northern Andes-Caribbean margin |url=https://www.sciencedirect.com/science/article/abs/pii/S0012825219302351 |journal=Earth-Science Reviews |volume=198 |pages=102903 |doi=10.1016/j.earscirev.2019.102903 |bibcode=2019ESRv..19802903M |issn=0012-8252 |access-date=2024-08-19 |archive-date=2024-04-16 |archive-url=https://web.archive.org/web/20240416183511/https://www.sciencedirect.com/science/article/abs/pii/S0012825219302351 |url-status=live }}</ref>

During the Eocene (c. 45 Ma), subduction of the Farallon plate along the Central American subduction zone was (re)established.<ref name=":16" /> Subduction along the northern section of the Caribbean volcanic arc ceased as the Bahamas carbonate platform collided with Cuba and was replaced by strike-slip movements as a transform fault, extending from the Mid-Atlantic Ridge, connected with the northern boundary of the Caribbean Plate. Subduction now focused along the southern Caribbean arc ([[Lesser Antilles Volcanic Arc|Lesser Antilles]]).<ref name=":16" /><ref>{{Cite journal |last1=van Benthem |first1=Steven |last2=Govers |first2=Rob |last3=Spakman |first3=Wim |last4=Wortel |first4=Rinus |date=2013 |title=Tectonic evolution and mantle structure of the Caribbean |url=https://agupubs.onlinelibrary.wiley.com/doi/10.1002/jgrb.50235 |journal=Journal of Geophysical Research: Solid Earth |language=en |volume=118 |issue=6 |pages=3019–3036 |doi=10.1002/jgrb.50235 |bibcode=2013JGRB..118.3019V |issn=2169-9313 |access-date=2024-08-19 |archive-date=2024-09-27 |archive-url=https://web.archive.org/web/20240927030627/https://agupubs.onlinelibrary.wiley.com/doi/10.1002/jgrb.50235 |url-status=live }}</ref>

By the Oligocene, the intra-oceanic [[Central America Volcanic Arc|Central American volcanic arc]] began to collide with northwestern South American.<ref name=":17" />

=== Pacific Ocean ===
At the beginning of the Paleogene, the Pacific Ocean consisted of the Pacific, Farallon, [[Kula plate|Kula]] and [[Izanagi plate|Izanagi]] plates. The central Pacific plate grew by seafloor spreading as the other three plates were subducted and broken up. In the southern Pacific, seafloor spreading continued from the Late Cretaceous across the Pacific–Antarctic, Pacific-Farallon and Farallon–Antarctic mid ocean ridges.<ref name=":1" />

The Izanagi-Pacific spreading ridge lay nearly parallel to the East Asian subduction zone and between 60–50 Ma the spreading ridge began to be subducted. By c. 50 Ma, the Pacific plate was no longer surrounded by spreading ridges, but had a subduction zone along its western edge. This changed the forces acting on the Pacific plate and led to a major reorganisation of plate motions across the entire Pacific region.<ref name=":18">{{Cite journal |last1=Seton |first1=Maria |last2=Flament |first2=Nicolas |last3=Whittaker |first3=Joanne |last4=Müller |first4=R. Dietmar |last5=Gurnis |first5=Michael |last6=Bower |first6=Dan J. |date=2015-03-28 |title=Ridge subduction sparked reorganization of the Pacific plate-mantle system 60–50 million years ago |url=https://agupubs.onlinelibrary.wiley.com/doi/10.1002/2015GL063057 |journal=Geophysical Research Letters |language=en |volume=42 |issue=6 |pages=1732–1740 |doi=10.1002/2015GL063057 |bibcode=2015GeoRL..42.1732S |issn=0094-8276}}</ref> The resulting changes in stress between the Pacific and [[Philippine Sea plate|Philippine Sea]] plates initiated subduction along the [[Izu–Bonin–Mariana Arc|Izu-Bonin-Mariana]] and [[Kermadec-Tonga subduction zone|Tonga-Kermadec]] arcs.<ref name=":18" /><ref name=":16" />

Subduction of the Farallon plate beneath the American plates continued from the Late Cretaceous.<ref name=":1" /> The Kula-Farallon spreading ridge lay to its north until the Eocene (c. 55 Ma), when the northern section of the plate split forming the [[Juan de Fuca plate|Vancouver/Juan de Fuca plate]].<ref name=":16" /> In the Oligocene (c. 28 Ma), the first segment of the Pacific–Farallon spreading ridge entered the North American subduction zone near [[Baja California]]<ref name=":19">{{Cite journal |last1=Wright |first1=Nicky M. |last2=Seton |first2=Maria |last3=Williams |first3=Simon E. |last4=Müller |first4=R. Dietmar |date=2016-03-01 |title=The Late Cretaceous to recent tectonic history of the Pacific Ocean basin |url=https://www.sciencedirect.com/science/article/abs/pii/S001282521530074X |journal=Earth-Science Reviews |volume=154 |pages=138–173 |doi=10.1016/j.earscirev.2015.11.015 |bibcode=2016ESRv..154..138W |issn=0012-8252}}</ref> leading to major strike-slip movements and the formation of the [[San Andreas Fault]].<ref name=":1" /> At the Paleogene-Neogene boundary, spreading ceased between the Pacific and Farallon plates and the Farallon plate split again forming the present date [[Nazca plate|Nazca]] and [[Cocos plate|Cocos]] plates.<ref name=":16" /><ref name=":19" />

The Kula plate lay between Pacific plate and North America. To the north and northwest it was being subducted beneath the [[Aleutian Trench|Aleutian trench]].<ref name=":1" /><ref name=":16" /> Spreading between the Kula and Pacific and Farallon plates ceased c. 40 Ma and the Kula plate became part of the Pacific Plate.<ref name=":1" /><ref name=":16" />

==== Hawaii hotspot ====
The [[Hawaiian–Emperor seamount chain|Hawaiian-Emperor seamount chain]] formed above the [[Hawaii hotspot|Hawaiian hotspot]]. Originally thought to be stationary within the mantle, the hotspot is now considered to have drifted south during the Paleocene to early Eocene, as the Pacific plate moved north. At c. 47 Ma, movement of the hotspot ceased and the Pacific plate motion changed from northward to northwestward in response to the onset of subduction along its western margin. This resulted in a 60 degree bend in the seamount chain. Other seamount chains related to hotspots in the South Pacific show a similar change in orientation at this time.<ref>{{Cite journal |last1=Jiang |first1=Zhaoxia |last2=Li |first2=Sanzhong |last3=Liu |first3=Qingsong |last4=Zhang |first4=Jianli |last5=Zhou |first5=Zaizheng |last6=Zhang |first6=Yuzhen |date=2021-04-01 |title=The trials and tribulations of the Hawaii hot spot model |url=https://www.sciencedirect.com/science/article/abs/pii/S001282522100043X |journal=Earth-Science Reviews |volume=215 |pages=103544 |doi=10.1016/j.earscirev.2021.103544 |bibcode=2021ESRv..21503544J |issn=0012-8252 |access-date=2024-08-19 |archive-date=2023-11-08 |archive-url=https://web.archive.org/web/20231108111121/https://www.sciencedirect.com/science/article/abs/pii/S001282522100043X |url-status=live }}</ref>

=== Antarctica ===
Slow seafloor spreading continued between Australia and East Antarctica. Shallow water channels probably developed south of Tasmania opening the [[Tasmanian Passage]] in the Eocene and deep ocean routes opening from the mid Oligocene. Rifting between the Antarctic Peninsula and the southern tip of South America formed the [[Drake Passage]] and opened the Southern Ocean also during this time, completing the breakup of Gondwana. The opening of these passages and the creation of the Southern Ocean established the [[Antarctic Circumpolar Current]]. [[Glacier|Glaciers]] began to build across the Antarctica continent that now lay isolated in the south polar region and surrounded by cold ocean waters. These changes contributed to the fall in global temperatures and the beginning of icehouse conditions.<ref name=":13" />[[File:Paleogene flood basalts, Ethiopia.jpg|thumb|Paleogene flood basalts on the Ethiopian Plateau with the Afar Depression in the background.|alt=Photo of a cliff face showing layers of basalt lava flows]]

=== Red Sea and East Africa ===
Extensional stresses from the subduction zone along the northern Neotethys resulted in rifting between Africa and Arabia, forming the [[Gulf of Aden]] in the late Eocene.<ref name=":20">{{Cite journal |last1=Boone |first1=Samuel C. |last2=Balestrieri |first2=Maria-Laura |last3=Kohn |first3=Barry |date=2021 |title=Tectono-Thermal Evolution of the Red Sea Rift |journal=Frontiers in Earth Science |language=English |volume=9 |page=588 |doi=10.3389/feart.2021.713448 |doi-access=free |bibcode=2021FrEaS...9..588B |issn=2296-6463|hdl=11343/289555 |hdl-access=free }}</ref> To the west, in the early Oligocene, [[Flood basalt|flood basalts]] erupted across [[Ethiopia]], northeast [[Sudan]] and southwest [[Yemen]] as the [[Afar Region|Afar]] mantle plume began to impact the base of the African lithosphere.<ref name=":1" /><ref name=":20" /> Rifting across the southern [[Red Sea]] began in the mid Oligocene, and across the central and northern Red Sea regions in the late Oligocene and early Miocene.<ref name=":20" />

== Climate ==
Climatic conditions varied considerably during the Paleogene. After the disruption of the [[Chicxulub crater|Chicxulub impact]] settled, a period of cool and dry conditions continued from the Late Cretaceous. At the Paleocene-Eocene boundary global temperatures rose rapidly with the onset of the [[Paleocene–Eocene Thermal Maximum|Paleocene-Eocene Thermal Maximum]] (PETM).<ref name=":1" /> By the middle Eocene, temperatures began to drop again and by the late Eocene (c. 37 Ma) had decreased sufficiently for ice sheets to form in Antarctica. The global climate entered icehouse conditions at the Eocene-Oligocene boundary and the present day [[Late Cenozoic Ice Age|Late Cenozoic ice age]] began.<ref name=":13" />

The Paleogene began with the brief but intense "[[impact winter]]" caused by the [[Chicxulub crater|Chicxulub impact]], which was followed by an abrupt period of warming. After temperatures stabilised, the steady cooling and drying of the Late Cretaceous-Early Paleogene Cool Interval that had spanned the last two [[Age (geology)|age]]s of the [[Late Cretaceous]] continued,<ref name="Scotese-2021">{{Cite journal |last1=Scotese |first1=Christopher Robert |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://linkinghub.elsevier.com/retrieve/pii/S0012825221000027 |journal=[[Earth-Science Reviews]] |language=en |volume=215 |page=103503 |doi=10.1016/j.earscirev.2021.103503 |bibcode=2021ESRv..21503503S |s2cid=233579194 |access-date=23 September 2023 |archive-date=10 August 2023 |archive-url=https://web.archive.org/web/20230810144728/https://linkinghub.elsevier.com/retrieve/pii/S0012825221000027 |url-status=live }}</ref> with only the brief interruption of the [[Danian#Latest Danian Event|Latest Danian Event]] (c. 62.2 Ma) when global temperatures rose.<ref name="LatestDanianEvent">{{cite journal |last1=Jehle |first1=Sofie |last2=Bornemann |first2=André |last3=Lägel |first3=Anna Friederike |last4=Deprez |first4=Arne |last5=Speijer |first5=Robert P. |date=1 July 2019 |title=Paleoceanographic changes across the Latest Danian Event in the South Atlantic Ocean and planktic foraminiferal response |url=https://www.sciencedirect.com/science/article/abs/pii/S003101821830854X#! |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=525 |pages=1–13 |bibcode=2019PPP...525....1J |doi=10.1016/j.palaeo.2019.03.024 |s2cid=134929774 |access-date=30 December 2022}}</ref><ref name="jehleetal2015">{{cite journal |last1=Jehle |first1=Sofie |last2=Bornemann |first2=André |last3=Deprez |first3=Arne |last4=Speijer |first4=Robert P. |date=25 November 2015 |title=The Impact of the Latest Danian Event on Planktic Foraminiferal Faunas at ODP Site 1210 (Shatsky Rise, Pacific Ocean) |journal=[[PLOS ONE]] |volume=10 |issue=11 |pages=e0141644 |bibcode=2015PLoSO..1041644J |doi=10.1371/journal.pone.0141644 |pmc=4659543 |pmid=26606656 |doi-access=free}}</ref><ref>{{cite journal |last1=Sprong |first1=M. |last2=Youssef |first2=J. A. |last3=Bornemann |first3=André |last4=Schulte |first4=P. |last5=Steurbaut |first5=E. |last6=Stassen |first6=P. |last7=Kouwenhoven |first7=T. J. |last8=Speijer |first8=Robert P. |date=September 2011 |title=A multi-proxy record of the Latest Danian Event at Gebel Qreiya, Eastern Desert, Egypt |url=https://core.ac.uk/download/pdf/34511141.pdf |journal=Journal of Micropalaeontology |volume=30 |issue=2 |pages=167–182 |doi=10.1144/0262-821X10-023 |bibcode=2011JMicP..30..167S |s2cid=55038043 |access-date=30 December 2022 |archive-date=28 June 2023 |archive-url=https://web.archive.org/web/20230628093332/https://core.ac.uk/download/pdf/34511141.pdf |url-status=dead }}</ref> There is no evidence for ice sheets at the poles during the Paleocene.<ref name=":1" />

The relatively cool conditions were brought to an end by the Thanetian Thermal Event, and the beginning of the PETM.<ref name="Scotese-2021" /> This was one of the warmest times of the Phanerozoic eon, during which global mean surface temperatures increased to 31.6 °C.<ref>{{Cite journal |last1=Sauermilch |first1=Isabel |last2=Whittaker |first2=Joanne M. |last3=Klocker |first3=Andreas |last4=Munday |first4=David R. |last5=Hochmuth |first5=Katharina |last6=Bijl |first6=Peter K. |last7=LaCasce |first7=Joseph H. |date=9 November 2021 |title=Gateway-driven weakening of ocean gyres leads to Southern Ocean cooling |journal=[[Nature Communications]] |language=en |volume=12 |issue=1 |page=6465 |bibcode=2021NatCo..12.6465S |doi=10.1038/s41467-021-26658-1 |issn=2041-1723 |pmc=8578591 |pmid=34753912}}</ref> According to a study published in 2018, from about 56 to 48 Ma, annual air temperatures over land and at mid-latitude averaged about 23–29&nbsp;°C (± 4.7&nbsp;°C).<ref>{{cite journal |author=Naafs, B. D. A. |author2=Rohrssen, M. |author3=Inglis, G. N. |author4=Lähteenoja, O. |author5=Feakins, S. J. |author6=Collinson, M. E. |author7=Kennedy, E. M. |author8=Singh, P. K. |author9=Singh, M. P. |author10=Lunt, D. J. |author11=Pancost, R. D. |year=2018 |title=High temperatures in the terrestrial mid-latitudes during the early Palaeogene |url=https://research-information.bristol.ac.uk/files/159708447/Combined_manuscript_submitted_June_2018.pdf |journal=[[Nature Geoscience]] |volume=11 |issue=10 |pages=766–771 |bibcode=2018NatGe..11..766N |doi=10.1038/s41561-018-0199-0 |s2cid=135045515 |hdl=1983/82e93473-2a5d-4a6d-9ca1-da5ebf433d8b |access-date=2019-09-24 |archive-date=2019-04-27 |archive-url=https://web.archive.org/web/20190427045702/https://research-information.bristol.ac.uk/files/159708447/Combined_manuscript_submitted_June_2018.pdf |url-status=live }}</ref><ref>{{cite news |last1=University of Bristol |date=30 July 2018 |title=Ever-increasing CO2 levels could take us back to the tropical climate of Paleogene period |work=ScienceDaily}}</ref><ref name="University of Bristol-2018">{{cite web |year=2018 |title=Ever-increasing CO2 levels could take us back to the tropical climate of Paleogene period |url=https://www.bristol.ac.uk/news/2018/july/co2-levels-paleogene-period.html |work=University of Bristol |access-date=2018-08-10 |archive-date=2019-10-31 |archive-url=https://web.archive.org/web/20191031143616/https://www.bristol.ac.uk/news/2018/july/co2-levels-paleogene-period.html |url-status=live }}</ref> For comparison, this was 10 to 15&nbsp;°C higher than the current annual mean temperatures in these areas.<ref name="University of Bristol-2018" /> 

This rapid rise in global temperatures and intense greenhouse conditions were due to a sudden increase in levels of atmospheric [[Carbon dioxide in Earth's atmosphere|carbon dioxide]] (CO<sub>2</sub>) and other [[Greenhouse gas|greenhouse gases]].<ref name=":13" /> An accompanying rise in humidity is reflected in an increase in [[kaolinite]] in sediments, which forms by [[Weathering|chemical weathering]] in hot, humid conditions.<ref name=":1" /> Tropical and subtropical forests flourished and extended into polar regions. Water vapour (a greenhouse gas) associated with these forests also contributed to the greenhouse conditions.<ref name=":13" />

The initial rise in global temperatures was related to the intrusion of magmatic [[Sill (geology)|sills]] into organic-rich sediments during volcanic activity in the North Atlantic Igneous Province, between about 56 and 54 Ma, which rapidly released large amounts of greenhouse gases into the atmosphere.<ref name=":1" /> This warming led to melting of frozen [[Methane clathrate|methane hydrates]] on [[Continental margin|continental slopes]] adding further greenhouses gases. It also reduced the rate of burial of organic matter as higher temperatures accelerated the rate of bacterial [[decomposition]] which released CO<sub>2</sub> back into the oceans.<ref name=":13" />

The (relatively) sudden climatic changes associated with the PETM resulted in the extinction of some groups of fauna and flora and the rise of others. For example, with the warming of the Arctic Ocean, around 70% of deep sea [[foraminifera]] species went extinct,<ref name=":13" /> whilst on land many modern mammals, including [[Primate|primates]], appeared.<ref>{{Cite journal |last1=van der Meulen |first1=Bas |last2=Gingerich |first2=Philip D. |last3=Lourens |first3=Lucas J. |last4=Meijer |first4=Niels |last5=van Broekhuizen |first5=Sjors |last6=van Ginneken |first6=Sverre |last7=Abels |first7=Hemmo A. |date=2020-03-15 |title=Carbon isotope and mammal recovery from extreme greenhouse warming at the Paleocene–Eocene boundary in astronomically-calibrated fluvial strata, Bighorn Basin, Wyoming, USA |url=https://www.sciencedirect.com/science/article/abs/pii/S0012821X19307393 |journal=Earth and Planetary Science Letters |volume=534 |pages=116044 |doi=10.1016/j.epsl.2019.116044 |bibcode=2020E&PSL.53416044V |issn=0012-821X |access-date=2024-09-05 |archive-date=2024-04-19 |archive-url=https://web.archive.org/web/20240419062255/https://www.sciencedirect.com/science/article/abs/pii/S0012821X19307393 |url-status=live }}</ref> Fluctuating sea levels meant, during low stands, a land bridge formed across the [[Bering Strait|Bering Straits]] between North America and Eurasia allowing the movement of land animals between the two continents.<ref name=":1" />

The PETM was followed by the less severe [[Eocene Thermal Maximum 2]] (c. 53.69 Ma),<ref name="Stap2010">{{Cite journal |author=Stap, L. |author2=Lourens, L.J. |author3=Thomas, E. |author4=Sluijs, A. |author5=Bohaty, S. |author6=Zachos, J.C. |date=1 July 2010 |title=High-resolution deep-sea carbon and oxygen isotope records of Eocene Thermal Maximum 2 and H2 |url=https://pubs.geoscienceworld.org/gsa/geology/article-abstract/38/7/607/130287/High-resolution-deep-sea-carbon-and-oxygen-isotope?redirectedFrom=fulltext |journal=[[Geology (journal)|Geology]] |volume=38 |issue=7 |pages=607–610 |bibcode=2010Geo....38..607S |doi=10.1130/G30777.1 |s2cid=41123449 |hdl=1874/385773|hdl-access=free }}</ref> and the Eocene Thermal Maximum 3 (c. 53 Ma). The early Eocene warm conditions were brought to an end by the [[Azolla event]]. This change of climate at about 48.5 Ma, is believed to have been caused by a proliferation of aquatic ferns from the genus ''[[Azolla]]'', resulting in the sequestering of large amounts of CO<sub>2</sub> from the atmosphere by the plants. From this time until about 34 Ma, there was a slow cooling trend known as the Middle-Late Eocene Cooling.<ref name="Scotese-2021" /> As temperatures dropped at high latitudes the presence of cold water [[Diatom|diatoms]] suggests sea ice was able to form in winter in the Arctic Ocean,<ref name=":13" /> and by the late Eocene (c. 37 Ma) there is evidence of glaciation in Antarctica.<ref name=":1" /> 

Changes in deep ocean currents, as Australia and South America moved away from Antarctica opening the Drake and Tasmanian passages, were responsible for the drop in global temperatures. The warm waters of the South Atlantic, Indian and South Pacific oceans extended southward into the opening Southern Ocean and became part of the cold circumpolar current. Dense polar waters sank into the deep oceans and moved northwards, reducing global ocean temperatures. This cooling may have occurred over less than 100,000 years and resulted in a widespread extinction in marine life. By the Eocene-Oligocene boundary, sediments deposited in the ocean from glaciers indicate the presence of an ice sheet in western Antarctica that extended to the ocean.<ref name=":13" />

The development of the circumpolar current led to changes in the oceans, which in turn reduced atmospheric CO<sub>2</sub> further. Increasing upwellings of cold water stimulated the productivity of [[phytoplankton]], and the cooler waters reduced the rate of bacterial decay of organic matter and promoted the growth of methane hydrates in marine sediments. This created a positive feedback cycle where global cooling reduced atmospheric CO<sub>2</sub> and this reduction in CO<sub>2</sub> lead to changes which further lowered global temperatures. The decrease in [[evaporation]] from the cooler oceans also reduced moisture in the atmosphere and increased aridity. By the early Oligocene, the North American and Eurasian tropical and subtropical forests were replaced by dry woodlands and widespread grasslands.<ref name=":13" />

The Early Oligocene Glacial Maximum lasted for about 200,000 years,<ref>{{Cite journal |last1=Zachos |first1=James C. |last2=Lohmann |first2=Kyger C. |last3=Walker |first3=James C. G. |last4=Wise |first4=Sherwood W. |date=March 1993 |title=Abrupt Climate Change and Transient Climates during the Paleogene: A Marine Perspective |url=https://www.journals.uchicago.edu/doi/10.1086/648216 |journal=[[The Journal of Geology]] |language=en |volume=101 |issue=2 |pages=191–213 |doi=10.1086/648216 |pmid=11537739 |bibcode=1993JG....101..191Z |s2cid=29784731 |issn=0022-1376 |access-date=23 September 2023 |archive-date=9 November 2023 |archive-url=https://web.archive.org/web/20231109112624/https://www.journals.uchicago.edu/doi/10.1086/648216 |url-status=live }}</ref> and the global mean surface temperature continued to decrease gradually during the [[Rupelian]].<ref name="Scotese-2021" /> A drop in global sea levels during the mid Oligocene indicates major growth of the Antarctic glacial ice sheet.<ref name=":13" /> In the [[Chattian|Late Oligocene]], global temperatures began to warm slightly, though they continued to be significantly lower than during the previous [[Epoch (geology)|epoch]]s of the Paleogene and polar ice remained.<ref name="Scotese-2021" />

==Flora and fauna==
[[File:Palaeotherium medium Life Reconstruction.png|thumb|left|Restoration of ''[[Palaeotherium]]'', which diversified in warmer climates]]
Tropical taxa diversified faster than those at higher latitudes after the Cretaceous–Paleogene extinction event, resulting in the development of a significant latitudinal diversity gradient.<ref>{{cite journal |last1=Crame |first1=J. Alistair |date=March 2020 |title=Early Cenozoic evolution of the latitudinal diversity gradient |journal=[[Earth-Science Reviews]] |volume=202 |page=103090 |doi=10.1016/j.earscirev.2020.103090 |bibcode=2020ESRv..20203090C |s2cid=214219923 |doi-access=free }}</ref> 

[[Mammal]]s began a rapid [[Biodiversity|diversification]] during this period. After the Cretaceous–Paleogene extinction event, which saw the demise of the non-avian [[dinosaur]]s, mammals began to evolve from a few small and generalized forms into most of the modern varieties we see presently. Some of these mammals evolved into large forms that dominated the land, while others became capable of living in [[ocean|marine]], specialized terrestrial, and airborne environments. Those that adapted to the oceans became modern [[cetacean]]s and [[sirenian]]s, while those that adapted to trees became [[primate]]s, the group to which humans belong. 

[[Birds]], extant [[dinosaurs]] which were already well established by the end of the [[Cretaceous]], also experienced [[adaptive radiation]] as they took over the skies left empty by the now extinct [[pterosaur]]s. Some flightless birds such as [[penguin]]s, [[ratites]], and [[terror birds]] also filled niches left by the [[hesperornithes]] and other extinct dinosaurs.

[[Lanternfish|Myctophids]] first appeared in the Late Palaeocene or Early Eocene, and during the Eocene and most of the Oligocene were restricted to shelf seas before expanding their range into the open ocean during the warm climatic interval at the end of the Oligocene.<ref>{{Cite journal |last1=Schwarzhans |first1=Werner |last2=Carnevale |first2=Giorgio |date=August 2021 |title=The rise to dominance of lanternfishes (Teleostei: Myctophidae) in the oceanic ecosystems: a paleontological perspective |journal=[[Paleobiology (journal)|Paleobiology]] |language=en |volume=47 |issue=3 |pages=446–463 |doi=10.1017/pab.2021.2 |issn=0094-8373 |doi-access=free }}</ref>

Pronounced cooling in the [[Oligocene]] resulted in a massive floral shift, and many extant modern plants arose during this time. [[Poaceae|Grasses]] and herbs, such as ''[[Artemisia (genus)|Artemisia]]'', began to proliferate, at the expense of tropical plants, which began to decrease. [[Pinophyta|Conifer]] forests developed in mountainous areas. This cooling trend continued, with major fluctuation, until the end of the [[Pleistocene]] period.<ref>{{Cite book|title=Paleopalynology|author=Traverse, Alfred|date=1988|publisher=Unwin Hyman|isbn=978-0-04-561001-3|oclc=17674795}}</ref> This evidence for this floral shift is found in the [[Palynology|palynological]] record.<ref>{{Cite journal|last=Muller|first=Jan|date=January 1981|title=Fossil pollen records of extant angiosperms|journal=The Botanical Review|volume=47|issue=1|pages=1–142|doi=10.1007/bf02860537|bibcode=1981BotRv..47....1M |s2cid=10574478|issn=0006-8101}}</ref>

==See also==
*{{annotated link|Cretaceous–Paleogene boundary}}

==References==
{{reflist}}

==External links==
{{Wikisource portal|Cenozoic#Paleogene}}
{{Commons category|Paleogene}}
*[http://www.foraminifera.eu/querydb.php?period=Paleogene&aktion=suche Paleogene Microfossils: 180+ images of Foraminifera]
*[https://ghkclass.com/ghkC.html?paleogene Paleogene (chronostratigraphy scale)]

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