Editing Chicxulub crater (section)

==Impact specifics==
[[File:Chicxulub Free-Air Gravity anomaly.png|thumb|[[Free-air gravity anomaly]] over the Chicxulub structure (coastline and state boundaries shown as black lines)]]

A 2013 study published in ''[[Science (journal)|Science]]'' estimated the age of the impact as 66,043,000 ± 11,000 years ago (± 43,000 years ago considering systematic error), based on multiple lines of evidence, including [[argon–argon dating]] of tektites from Haiti and [[bentonite]] horizons overlying the impact horizon in northeastern [[Montana]].<ref name="RenneDeino2013" /> This date was supported by a 2015 study based on argon–argon dating of [[tephra]] found in [[lignite]] beds in the [[Hell Creek Formation|Hell Creek]] and overlying [[Fort Union Formation|Fort Union]] formations in northeastern Montana.<ref>{{Cite journal |last1=Sprain |first1=C.J. |last2=Renne |first2=P.R. |last3=Wilson |first3=G.P. |last4=Clemens |first4=W.A. |date=March 1, 2015 |title=High-resolution chronostratigraphy of the terrestrial Cretaceous-Paleogene transition and recovery interval in the Hell Creek region, Montana |url=https://pubs.geoscienceworld.org/gsabulletin/article/127/3-4/393-409/126101 |journal=Geological Society of America Bulletin |language=en |volume=127 |issue=3–4 |pages=393–409 |bibcode=2015GSAB..127..393S |doi=10.1130/B31076.1 |issn=0016-7606 |s2cid=129291530}}</ref> A 2018 study based on argon–argon dating of spherules from [[Gorgona Island (Colombia)|Gorgonilla Island]], [[Colombia]], obtained a slightly different result of 66,051,000 ± 31,000 years ago.<ref>{{Cite journal |last1=Renne |first1=Paul R. |last2=Arenillas |first2=Ignacio |last3=Arz |first3=José A. |last4=Vajda |first4=Vivi |last5=Gilabert |first5=Vicente |last6=Bermúdez |first6=Hermann D. |display-authors=3 |date=June 1, 2018 |title=Multi-proxy record of the Chicxulub impact at the Cretaceous-Paleogene boundary from Gorgonilla Island, Colombia |url=https://pubs.geoscienceworld.org/gsa/geology/article/46/6/547/530690/Multiproxy-record-of-the-Chicxulub-impact-at-the |journal=Geology |language=en |volume=46 |issue=6 |pages=547–550 |bibcode=2018Geo....46..547R |doi=10.1130/G40224.1 |issn=0091-7613 |s2cid=135274460}}</ref> The impact has been interpreted to have occurred in the Northern Hemisphere's spring season based on annual [[isotope analysis|isotope curves]] in [[sturgeon]] and [[paddlefish]] bones found in an ejecta-bearing sedimentary unit at the [[Tanis (fossil site)|Tanis site]] in southwestern [[North Dakota]]. This sedimentary unit is thought to have formed within hours of impact.<ref>{{Cite journal |last1=During |first1=Melanie A.D. |last2=Smit |first2=Jan |last3=Voeten |first3=Dennis F.A.E. |last4=Berruyer |first4=Camille |last5=Tafforeau |first5=Paul |last6=Sanchez |first6=Sophie |last7=Stein |first7=Koen H. W. |last8=Verdegaal-Warmerdam |first8=Suzan J.A. |last9=van der Lubbe |first9=Jeroen H.J.L. |display-authors=3 |date=February 23, 2022 |title=The Mesozoic terminated in boreal spring |journal=Nature |volume=603 |issue=7899 |pages=91–94 |bibcode=2022Natur.603...91D |doi=10.1038/s41586-022-04446-1 |pmc=8891016 |pmid=35197634}}</ref> 

The site of the crater at the time of impact was a marine [[carbonate platform]].<ref name="Gulick_etal_2013">{{Cite journal |last1=Gulick |first1=S.P.S. |last2=Christeson |first2=G.L. |last3=Barton |first3=P.J. |last4=Grieve |first4=R.A.F. |last5=Morgan |first5=J.V.|author5-link= Joanna Morgan |last6=Urrutia-Fucugauchi |first6=J. |display-authors=3 |date=January 2013 |title=Geophysical characterization of the Chicxulub impact crater |journal=Reviews of Geophysics |language=en |volume=51 |issue=1 |pages=31–52 |bibcode=2013RvGeo..51...31G |doi=10.1002/rog.20007 |issn=8755-1209 |s2cid=55502139|doi-access=free }}</ref> The water depth at the impact site varied from {{Convert|100|m|ft|sp=us}} on the western edge of the crater to over {{Convert|1200|m|ft|sp=us}} on the northeastern edge, with an estimated depth at the centre of the impact of approximately {{Convert|650|m|ft|sp=us}}.<ref name="Gulick_etal_2008">{{Cite journal |last1=Gulick |first1=Sean P. S. |last2=Barton |first2=Penny J. |last3=Christeson |first3=Gail L. |last4=Morgan |first4=Joanna V.|author4-link= Joanna Morgan |last5=McDonald |first5=Matthew |last6=Mendoza-Cervantes |first6=Keren |last7=Pearson |first7=Zulmacristina F. |last8=Surendra |first8=Anusha |last9=Urrutia-Fucugauchi |first9=Jaime |last10=Vermeesch |first10=Peggy M. |last11=Warner |first11=Mike R. |display-authors=3 |date=February 2008 |title=Importance of pre-impact crustal structure for the asymmetry of the Chicxulub impact crater |url=http://www.nature.com/articles/ngeo103 |journal=Nature Geoscience |language=en |volume=1 |issue=2 |pages=131–135 |bibcode=2008NatGe...1..131G |doi=10.1038/ngeo103 |issn=1752-0894 |s2cid=128949260}}</ref> The seafloor rocks consisted of a sequence of [[Jurassic]]–[[Cretaceous]] marine sediments {{Convert|3|km|mi|sp=us}} thick. They were predominantly [[carbonate rock]], including [[Dolomite (rock)|dolomite]] (35–40% of total sequence) and [[limestone]] (25–30%), along with [[evaporite]]s ([[anhydrite]] 25–30%) and minor amounts of [[shale]] and [[sandstone]] (3–4%) underlain by approximately {{Convert|35|km|mi|sp=us}} of [[continental crust]], composed of [[Igneous rock|igneous]] [[Basement (geology)|crystalline basement]] including [[granite]].<ref>{{Cite journal |last1=Navarro |first1=Karina F. |last2=Urrutia-Fucugauchi |first2=Jaime |last3=Villagran-Muniz |first3=Mayo |last4=Sánchez-Aké |first4=Citlali |last5=Pi-Puig |first5=Teresa |last6=Pérez-Cruz |first6=Ligia |last7=Navarro-González |first7=Rafael |display-authors=3 |date=August 2020 |title=Emission spectra of a simulated Chicxulub impact-vapor plume at the Cretaceous–Paleogene boundary |url=https://linkinghub.elsevier.com/retrieve/pii/S0019103520301962 |journal=Icarus |language=en |volume=346 |pages=113813 |bibcode=2020Icar..34613813N |doi=10.1016/j.icarus.2020.113813 |s2cid=218965047 |access-date=February 19, 2022 |archive-date=May 22, 2023 |archive-url=https://web.archive.org/web/20230522063946/https://linkinghub.elsevier.com/retrieve/pii/S0019103520301962 |url-status=live }}</ref>

The impactor was around {{convert|10|km|mi||abbr=off|sp=us}} in diameter<ref name="Desch et al_2021">{{Cite journal |last1=Desch |first1=Steve |last2=Jackson |first2=Alan |last3=Noviello |first3=Jessica |last4=Anbar |first4=Ariel |date=June 1, 2021 |title=The Chicxulub impactor: comet or asteroid? |journal=Astronomy & Geophysics |language=en |volume=62 |issue=3 |pages=3.34–3.37 |arxiv=2105.08768 |doi=10.1093/astrogeo/atab069 |issn=1366-8781 |s2cid=234777761}}</ref>—large enough that, if set at sea level, it would have reached taller than [[Mount Everest]].<ref name="Alvarez_2008">{{Cite book |last=Alvarez |first=Walter |title=T. Rex and the Crater of Doom |publisher=Princeton University Press |year=2008 |isbn=978-0-691-13103-0}}</ref>{{rp|9}} The impactor's velocity was estimated at {{convert|20|km/s|sp=us}} inclined 45–60° to horizontal, impacting from the northeast.<ref name="collins">{{Cite journal |last1=Collins |first1=G. S. |last2=Patel |first2=N. |last3=Davison |first3=T. M. |last4=Rae |first4=A. S. P. |last5=Morgan |first5=J. V.|author5-link= Joanna Morgan |last6=Gulick |first6=S. P. S. |date=May 26, 2020 |title=A steeply-inclined trajectory for the Chicxulub impact |journal=Nature Communications |volume=11 |issue=1 |pages=1480 |bibcode=2020NatCo..11.1480C |doi=10.1038/s41467-020-15269-x |s2cid=218898524 |issn=2041-1723 |pmc=7251121 |pmid=32457325}}</ref> 

===Effects===
[[File:Chicxulub-animation.gif|thumb|An animation showing the Chicxulub impact and subsequent crater formation|alt=see caption]]
The [[kinetic energy]] of the impact was estimated at {{convert|72|TtTNT}}.<ref name="Richards">{{Cite journal |last1=Richards |first1=Mark A. |last2=Alvarez |first2=Walter |author-link2=Walter Alvarez |last3=Self |first3=Stephen |author-link3=Stephen Self |last4=Karlstrom |first4=Leif |last5=Renne |first5=Paul R. |author-link5=Paul Renne |last6=Manga |first6=Michael |author-link6=Michael Manga |last7=Sprain |first7=Courtney J. |last8=Smit |first8=Jan |author-link8=Jan Smit (paleontologist) |last9=Vanderkluysen |first9=Loÿc |last10=Gibson |first10=Sally A. |date=November 2015 |title=Triggering of the largest Deccan eruptions by the Chicxulub impact |url=https://seismo.berkeley.edu/~manga/richardsetal2015.pdf |url-status=live |journal=[[GSA Bulletin]] |volume=127 |issue=11–12 |pages=1507–1520 |bibcode=2015GSAB..127.1507R |doi=10.1130/B31167.1 |archive-url=https://web.archive.org/web/20240414192356/http://seismo.berkeley.edu/~manga/richardsetal2015.pdf |archive-date=2024-04-14 |access-date=August 10, 2024 |s2cid=3463018 |issn=0016-7606}}</ref> The impact generated winds in excess of {{convert|1000|km/h|sp=us}} near the blast's center,<ref>{{Cite web |title=Chicxulub Impact Event: Regional Effects |url=https://www.lpi.usra.edu/science/kring/Chicxulub/regional-effects/ |url-status=live |archive-url=https://web.archive.org/web/20190726023401/https://www.lpi.usra.edu/science/kring/Chicxulub/regional-effects/ |archive-date=July 26, 2019 |access-date=June 1, 2020 |website=Lunar and Planetary Institute}}</ref> and produced a transient cavity {{convert|100|km|sp=us}} wide and {{convert|30|km|sp=us}} deep that later collapsed. This formed a crater mainly under the sea and currently covered by ~{{convert|1000|m|sp=us}} of [[sediment]].<ref name="Gulick_etal_2013"/><ref name="Amos_2017-05-15">{{Cite web |last=Amos, Jonathan |date=May 15, 2017 |title=Dinosaur asteroid hit 'worst possible place' |url=https://www.bbc.com/news/science-environment-39922998 |url-status=live |archive-url=https://web.archive.org/web/20180318162335/http://www.bbc.com/news/science-environment-39922998 |archive-date=March 18, 2018 |access-date=August 19, 2017 |website=[[BBC News]] |department=Science and Environment}}</ref> The impact, expansion of water after filling the crater, and related [[seismic]] activity spawned [[megatsunami]]s over {{convert|100|m|sp=us}} tall, with one simulation suggesting the immediate waves from the impact may have reached up to {{convert|1.5|km|sp=us}} high.<ref name=":2" /><ref name="Bryant">{{Cite book |last=Bryant |first=Edward |url=https://books.google.com/books?id=tOkpBAAAQBAJ&pg=PA178 |title=Tsunami: The underrated hazard |date=June 2014 |publisher=Springer |isbn=978-3-319-06133-7 |page=178}}</ref> The waves scoured the [[seabed|sea floor]], leaving ripples underneath what is now [[Louisiana]] with average wavelengths of {{convert|600|m|sp=us}} and average wave heights of {{convert|16|m|sp=us}}, the largest ripples documented.<ref>{{Cite web |last=Koumoundouros |first=Tessa |date=July 14, 2021 |title=Fossilized Tsunami 'Megaripples' Reveal The Devastation From The Chicxulub Asteroid |url=https://www.sciencealert.com/tsunami-megaripples-from-the-dinosaur-killing-asteroid-impact-discovered-in-louisiana |access-date=January 1, 2022 |website=ScienceAlert |language=en-gb}}</ref><ref name="sciencedirect.com">{{Cite journal |last1=Kinsland |first1=Gary L. |last2=Egedahl |first2=Kaare |last3=Strong |first3=Martell Albert |last4=Ivy |first4=Robert |date=September 15, 2021 |title=Chicxulub impact tsunami megaripples in the subsurface of Louisiana: Imaged in petroleum industry seismic data |url=https://www.sciencedirect.com/science/article/pii/S0012821X21003186 |journal=Earth and Planetary Science Letters |language=en |volume=570 |pages=117063 |bibcode=2021E&PSL.57017063K |doi=10.1016/j.epsl.2021.117063 |issn=0012-821X |s2cid=237653482}}</ref> Material shifted by subsequent earthquakes and the waves reached to what are now [[Texas]] and Florida, and may have disturbed sediments as far as {{convert|6000|km|sp=us}} from the impact site.<ref name="Palmer_2016-02-25">{{Cite web |last=Palmer, Jane |date=February 25, 2016 |title=We Finally Know How Much the Dino-Killing Asteroid Reshaped Earth |url=http://www.smithsonianmag.com/science-nature/we-finally-know-how-much-dino-killing-asteroid-reshaped-earth-180958222/ |url-status=live |archive-url=https://web.archive.org/web/20160228025905/http://www.smithsonianmag.com/science-nature/we-finally-know-how-much-dino-killing-asteroid-reshaped-earth-180958222/ |archive-date=February 28, 2016 |access-date=February 26, 2016 |website=Smithsonian.com |publisher=[[Smithsonian Institution]]}}</ref><ref name=":2">{{Cite web |date=December 20, 2018 |title=Huge Global Tsunami Followed Dinosaur-Killing Asteroid Impact |url=https://eos.org/articles/huge-global-tsunami-followed-dinosaur-killing-asteroid-impact |url-status=live |archive-url=https://web.archive.org/web/20200711221446/https://eos.org/articles/huge-global-tsunami-followed-dinosaur-killing-asteroid-impact |archive-date=July 11, 2020 |access-date=July 11, 2020}}</ref><ref name="bundled_Kazuhisa et al">{{Cite journal|last1=Goto|first1=Kazuhisa|last2=Tada|first2=Ryuji|last3=Tajika|first3=Eiichi|last4=Bralower|first4=Timothy J.|last5=Hasegawa|first5=Takashi|last6=Matsui|first6=Takafumi|display-authors=3|year=2004|title=Evidence for ocean water invasion into the Chicxulub crater at the Cretaceous/Tertiary boundary|journal=Meteoritics & Planetary Science|language=en|volume=39|issue=8|pages=1233–1247|doi=10.1111/j.1945-5100.2004.tb00943.x|s2cid=55674339|bibcode=2004M&PS...39.1233G|issn=1945-5100|doi-access=free}}, {{Cite journal|url=https://agu.confex.com/agu/fm18/meetingapp.cgi/Paper/445502|title=The Chicxulub Impact Produced a Powerful Global Tsunami|first1=Molly M.|last1=Range|first2=SAND-Brian K.|last2=Arbic|first3=Brandon C.|last3=Johnson|first4=Theodore Carlton|last4=Moore|first5=Alistair|last5=Adcroft|first6=Joseph K.|last6=Ansong|first7=Jeroen|last7=Ritsema|first8=Christopher|last8=Scotese|display-authors=3|journal=AGU Fall Meeting Abstracts|date=December 14, 2018|volume=2018|publisher=AGU|bibcode=2018AGUFMPP53B..07R|via=agu.confex.com|access-date=July 11, 2020|archive-date=July 15, 2020|archive-url=https://web.archive.org/web/20200715022234/https://agu.confex.com/agu/fm18/meetingapp.cgi/Paper/445502|url-status=live}}, {{Cite web |last1=Matsui |first1=T. |last2=Imamura |first2=F. |last3=Tajika |first3=E. |last4=Nakano |first4=Y. |last5=Fujisawa |first5=Y. |year=2002 |title=Generation and propagation of a tsunami from the Cretaceous-Tertiary impact event |url=https://www.researchgate.net/publication/228783220 |url-status=live |archive-url=https://web.archive.org/web/20211020080538/https://www.researchgate.net/publication/228783220_Generation_and_propagation_of_a_tsunami_from_the_Cretaceous-Tertiary_impact_event |archive-date=October 20, 2021 |access-date=March 29, 2021 |website=Research Gate |publisher=Special Paper of the Geological Society of America 356 |pages=69–77}}</ref> The impact triggered a seismic event with an estimated [[Moment magnitude scale|moment magnitude]] of 9–11 {{M|w}}.<ref name="Richards"/>

A cloud of hot dust, ash and steam would have spread from the crater, with as much as 25 trillion metric tons of excavated material being ejected into the atmosphere by the blast. Some of this material escaped orbit, dispersing throughout the [[Solar System]],<ref name="newyorker_2019-03-29" /> while some of it fell back to Earth, vaporizing upon [[Atmospheric entry|re-entry]]. The rock heated Earth's surface and ignited wildfires, estimated to have enveloped nearly 70% of the planet's forests. The effect on living creatures even hundreds of kilometers away was immense, and much of present-day Mexico and the United States would have been devastated.<ref name="Bates_1992"/><ref name="Alvarez_2008" />{{rp|10–13}}<ref name="newyorker_2019-03-29" /> Fossil evidence for an instantaneous extinction of diverse animals was found in a soil layer only {{convert|10|cm|sp=us}} thick in [[New Jersey]], {{convert|2500|km|sp=us}} away from the impact site, indicating that death and burial under debris occurred suddenly and quickly over wide distances on nearby land.<ref name="Amos_2017-05-15" /> Field research from the [[Hell Creek Formation]] in North Dakota published in 2019 shows the simultaneous mass extinction of myriad species, combined with geological and atmospheric features that are consistent with the impact event.<ref name="newyorker_2019-03-29">{{Cite magazine |last=Preston |first=Douglas |author-link=Douglas Preston |date=March 29, 2019 |title=The Day The Dinosaurs Died |url=https://www.newyorker.com/magazine/2019/04/08/the-day-the-dinosaurs-died |url-status=live |magazine=[[The New Yorker]] |archive-url=https://web.archive.org/web/20190518000523/https://www.newyorker.com/magazine/2019/04/08/the-day-the-dinosaurs-died |archive-date=May 18, 2019 |access-date=May 13, 2019}}</ref>

Due to the relatively shallow water at the impact site, the rock that was vaporized included sulfur-rich [[gypsum]] from the lower part of the Cretaceous sequence, and this was injected into the atmosphere.<ref name="Amos_2017-05-15" /> This global dispersal of dust and [[sulfate]]s would have led to a sudden and catastrophic effect on the climate worldwide, instigating large temperature drops and devastating the [[food chain]]. Researchers stated that the impact not only generated an environmental calamity that extinguished life, but it also induced a vast subsurface [[Hydrothermal circulation|hydrothermal system]] that became an oasis for the recovery of life.<ref name="Kring_2017" /><ref>{{Cite journal |last1=Shaulis |first1=Barry J. |last2=Riller |first2=Ulrich |last3=Cockell |first3=Charles |last4=Coolen |first4=Marco J.L. |year=2017 |title=Probing the impact-generated hydrothermal system in the peak ring of the Chicxulub crater and its potential as a habitat |url=https://www.hou.usra.edu/meetings/lpsc2017/pdf/1212.pdf |journal=Lunar and Planetary Science |volume=XLVIII |issue=1964 |page=1212 |bibcode=2017LPI....48.1212K |archive-url=https://web.archive.org/web/20201026101301/https://www.hou.usra.edu/meetings/lpsc2017/pdf/1212.pdf |archive-date=October 26, 2020}}</ref> Using seismic images of the crater in 2008, scientists determined that the impactor landed in deeper water than previously assumed, which may have resulted in increased sulfate [[aerosol]]s in the atmosphere as a result of more water vapor being available to react with the vaporized [[anhydrite]]. This could have made the impact even deadlier by rapidly cooling the climate and generating [[acid rain]].<ref>{{Cite news |last=Airhart |first=Marc |date=January 1, 2008 |title=Seismic Images Show Dinosaur-Killing Meteor Made Bigger Splash |url=http://www.jsg.utexas.edu/news/2008/01/seismic-images-show-dinosaur-killing-meteor-made-bigger-splash/ |url-status=live |access-date=November 29, 2011 |archive-url=https://web.archive.org/web/20141220175132/http://www.jsg.utexas.edu/news/2008/01/seismic-images-show-dinosaur-killing-meteor-made-bigger-splash/ |archive-date=December 20, 2014}}</ref>

The emission of dust and particles could have covered the entire surface of Earth for several years, possibly up to a decade, creating a harsh environment for biological life. Production of [[carbon dioxide]] caused by the destruction of [[carbonate]] rocks would have led to a sudden [[greenhouse effect]].<ref name="Hildebrand et al_1991-09"/>{{rp|5}} For over a decade or longer, sunlight would have been blocked from reaching the surface of Earth by the dust particles in the atmosphere, cooling the surface dramatically. [[Photosynthesis]] by plants would also have been interrupted, affecting the entire food chain.<ref name="perlman_2007-09-06">{{Cite news |last=Perlman |first=David |author-link=David Perlman |date=September 6, 2007 |title=Scientists say they know where dinosaur-killing asteroid came from |url=http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2007/09/06/MNVFRUVCK.DTL |url-status=live |archive-url=https://web.archive.org/web/20120404030311/http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2007/09/06/MNVFRUVCK.DTL |archive-date=April 4, 2012 |access-date=October 3, 2007 |journal=[[San Francisco Chronicle]]}}</ref><ref>{{Cite journal |last1=Pope KO |last2=Ocampo AC |last3=Kinsland GL |last4=Smith R |year=1996 |title=Surface expression of the Chicxulub crater |journal=[[Geology (journal)|Geology]] |volume=24 |issue=6 |pages=527–530 |bibcode=1996Geo....24..527P |doi=10.1130/0091-7613(1996)024<0527:SEOTCC>2.3.CO;2 |pmid=11539331}}  See also [https://ntrs.nasa.gov/api/citations/19980211540/downloads/19980211540.pdf a similar 1998 report by the same group].</ref> A model of the event developed by Lomax et al (2001) suggests that [[Primary production#GPP and NPP|net primary productivity]] rates may have increased to higher than pre-impact levels over the long term because of the high carbon dioxide concentrations.<ref name="Lomax">{{Cite journal |last1=Lomax |first1=B. |last2=Beerling |first2=D. |author-link2=David Beerling |last3=Upchurch |first3=G. Jr. |last4=Otto-Bliesner |first4=B. |year=2001 |title=Rapid (10-yr) recovery of terrestrial productivity in a simulation study of the terminal Cretaceous impact event |journal=Earth and Planetary Science Letters |volume=192 |issue=2 |pages=137–144 |bibcode=2001E&PSL.192..137L |doi=10.1016/S0012-821X(01)00447-2 |s2cid=140196018}}</ref>

A long-term local effect of the impact was the creation of the Yucatán sedimentary basin which "ultimately produced favorable conditions for human settlement in a region where surface water is scarce".<ref>{{Cite conference |last=Winemiller |first=Terance L. |year=2007 |title=The Chicxulub meteor impact and ancient locational decisions on the Yucatán Peninsula, Mexico: The application of remote sensing, GIS, and GPS in settlement pattern Studies |url=http://www.asprs.org/a/publications/proceedings/tampa2007/0080.pdf |conference=ASPRS 2007 Annual Conference |publisher=[[American Society for Photogrammetry and Remote Sensing]] |archive-url=https://web.archive.org/web/20170810112923/http://asprs.org/a/publications/proceedings/tampa2007/0080.pdf |archive-date=August 10, 2017 |access-date=October 2, 2012 |place=Tampa, Florida |url-status=live}}</ref>