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{{Short description|Impact crater in Siberia, Russia}}
{{Other uses|Popigay (disambiguation)}}
{{Infobox terrestrial impact site
| name = Popigai impact structure
| other_name = 
| photo = Popigai crater russia.jpg
| photo_size = 
| photo_alt = 
| photo_caption = [[Landsat program|Landsat]] image of Popigai crater
| map = Russia
| map_alt = 
| map_caption = Location of the crater in Russia
| map_size = 
| location = 
| label =
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| coordinates = {{coord|71|39|N|111|11|E|region:RU_type:landmark_scale:1000000|display=inline,title}}
| coordinates_ref = 
| confidence = Confirmed
| diameter = {{convert|90|km|mi|abbr=on}}
| depth = 
| rise =
| age = 35.7 ± 0.2 Ma<br />[[Eocene|Late Eocene]]
| exposed = Yes
| drilled = Yes
| imp_size = 
| bolide = [[H chondrite]]

| translation =
| language =
| pronunciation =
| topo = 
| access = 
| country = [[Russia]]
| state = 
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| municipality = 
|region=[[Krasnoyarsk Krai]]}}
[[File:Popigai crater DS1040-1037DA019-024.jpg|thumb|right|Popigai crater in April 1967]]
The '''Popigai impact structure''' is the eroded remnant of an [[impact crater]] in northern [[Siberia]], Russia. It is tied with the [[Acraman impact structure]] as the [[List of impact craters on Earth|fourth largest]] verified [[impact structure]] on [[Earth]].<ref>{{cite web|title=Impact Structures listed by Diameter (Increasing) |url=http://www.passc.net/EarthImpactDatabase/New%20website_05-2018/Diametersort.html|publisher=PASSC|access-date=24 April 2025}}</ref> A large [[bolide]] impact created the {{convert|100|km|mi|-diameter|adj=mid}} crater approximately 35 million years ago during the late [[Eocene]] epoch ([[Eocene#Grande Coupure|Priabonian stage]]).<ref name="Alexander">{{Cite journal
 |doi        = 10.1111/j.1945-5100.2006.tb00985.x
 |volume     = 41
 |pages      = 689–703
 |last       = Deutsch
 |first      = Alexander
 |author2    = Christian Koeberl
 |title      = Establishing the link between the Chesapeake Bay impact structure and the North American tektite strewn field: The Sr-Nd isotopic evidence
 |journal    = Meteoritics & Planetary Science
 |year       = 2006
 |issue      = 5
 |bibcode    = 2006M&PS...41..689D
|doi-access= free
 }}</ref><ref name=Armstrong>{{Cite book
| publisher = Springer
| pages = 99–116
| last = Armstrong
| first = Richard |author2=S. Vishnevsky |author3=C. Koeberl
| title = U-Pb Analysis of zircons from the Popigai impact structure, Russia: First Results
| year = 2003
| url = https://books.google.com/books?id=mLfsNALR19oC&q=Popigai+Chesapeake+age&pg=PA109
| isbn = 978-3-540-43517-4
}}</ref> It might be linked to the [[Eocene–Oligocene extinction event]].<ref>{{cite web|title=Russia's Popigai Meteor Crash Linked to Mass Extinction|website=[[Live Science]] |url=http://www.livescience.com/46312-popigai-crater-linked-eocene-mass-extinction.html|date=June 13, 2014}}</ref>

The structure  is {{convert|300|km|mi|abbr=on}} east from the outpost of [[Khatanga (village)|Khatanga]] and {{convert|880|km|mi|abbr=on}} northeast of the city of [[Norilsk]], NNE of the [[Anabar Plateau]]. It is designated by [[UNESCO]] as a [[Geopark]], a site of special geological heritage.<ref name="Alexander2">{{Cite journal
 |volume     = 23
 |pages      = 3–12
 |last       = Deutsch
 |first      = Alexander
 |author2    = V.L. Masaitis
 |author3    = F. Langenhorst
 |author4    = R.A.F. Grieve
 |title      = Popigai, Siberia—well preserved giant impact structure, national treasury, and world's geological heritage
 |journal    = Episodes
 |year       = 2000
 |issue      = 1
|doi = 10.18814/epiiugs/2000/v23i1/002
 |doi-access= free
 }}</ref> There is a small possibility that the Popigai impact crater may have formed simultaneously with the approximately 35-million-year-old [[Chesapeake Bay impact crater|Chesapeake Bay]] and [[Toms Canyon impact crater|Toms Canyon]] impact craters.<ref name="Alexander"/>
 
For decades, the Popigai impact structure has fascinated [[paleontologists]] and [[geologists]], but the entire area was completely off limits because of the diamonds found there. However, a major investigatory expedition was undertaken in 1997, which greatly advanced understanding of the structure.<ref name="Alexander2"/> The impactor is suggested to have been a [[H chondrite]] asteroid based on ejecta layers from Italy, with the impactor thought to have been several kilometres in diameter.<ref>{{Cite journal |last1=Schmitz |first1=Birger |last2=Boschi |first2=Samuele |last3=Cronholm |first3=Anders |last4=Heck |first4=Philipp R. |last5=Monechi |first5=Simonetta |last6=Montanari |first6=Alessandro |last7=Terfelt |first7=Fredrik |date=September 2015 |title=Fragments of Late Eocene Earth-impacting asteroids linked to disturbance of asteroid belt |journal=Earth and Planetary Science Letters |language=en |volume=425 |pages=77–83 |doi=10.1016/j.epsl.2015.05.041 |doi-access=free|bibcode=2015E&PSL.425...77S }}</ref>

The shock pressures from the impact instantaneously transformed [[graphite]] in the ground into [[diamond]]s within a {{convert|13.6|km|mi|abbr=on}} radius of the impact point. These diamonds are usually {{convert|0.5|to|2|mm|in|abbr=on}} in diameter, though a few exceptional specimens are {{convert|10|mm|in|abbr=on}} in size. The diamonds inherited the tabular shape of the original graphite grains and also the original crystals' delicate [[striation (geology)|striation]]s.<ref name="Alexander2"/>

== Diamond deposits ==
[[File:Popigai nanodiamonds.jpg|thumb|right|330px|Popigai diamonds are about 1 mm in size and consist of [[nanodiamond]] agglomerates.<ref>{{cite journal|doi=10.1038/srep14702|pmid=26424384|pmc=4589680|title=Natural occurrence of pure nano-polycrystalline diamond from impact crater|journal=Scientific Reports|volume=5|pages=14702|year=2015|last1=Ohfuji|first1=Hiroaki|last2=Irifune|first2=Tetsuo|last3=Litasov|first3=Konstantin D.|last4=Yamashita|first4=Tomoharu|last5=Isobe|first5=Futoshi|last6=Afanasiev|first6=Valentin P.|last7=Pokhilenko|first7=Nikolai P.|bibcode=2015NatSR...514702O}}</ref>]]
Most modern industrial diamonds are produced [[Synthetic diamond|synthetically]]. The diamond deposits at Popigai have not been mined because of the remote location and lack of infrastructure, and are unlikely to be competitive with synthetic diamonds.<ref name=geonews>{{cite news|title=Diamonds Beneath the Popigai Crater -- Northern Russia|url=http://geology.com/articles/popigai-crater-diamonds/|access-date=24 September 2012|date=23 September 2012|publisher=geology.com}}</ref>  Many of the diamonds at Popigai contain [[crystal lattice|crystalline]] [[lonsdaleite]], an [[allotrope of carbon]] that has a hexagonal lattice.<ref name=itartass>{{cite news|title=Russia declassifies deposit of impact diamonds|url=http://pda.itar-tass.com/en/c154/521362.html|publisher=ITAR-TASS|access-date=17 September 2012|date=17 September 2012|archive-url=https://web.archive.org/web/20120920221513/http://pda.itar-tass.com/en/c154/521362.html|archive-date=20 September 2012|url-status=dead}}</ref> Pure, laboratory-created lonsdaleite is up to 58% harder than ordinary diamonds.<ref name=theory>{{cite journal|author1=Pan, Zicheng |author2=Sun, Hong |author3=Zhang, Yi |author4=Chen, Changfeng  |name-list-style=amp |title=Harder than Diamond: Superior Indentation Strength of Wurtzite BN and Lonsdaleite |journal=Physical Review Letters|issue= 5|pages=055503|year=2009 |doi= 10.1103/PhysRevLett.102.055503|volume=102|pmid=19257519|bibcode=2009PhRvL.102e5503P}}
*{{cite news |author=Lisa Zyga |date=12 February 2009 |title=Scientists Discover Material Harder Than Diamond |work=Phys.org |url=http://www.physorg.com/news153658987.html}}</ref><ref name=geonews /> These types of diamonds are known as "impact diamonds" because they are thought to be produced when a meteorite strikes a graphite deposit at high velocity.<ref name=itartass/>  They may have industrial uses but are unsuitable as [[gem]]s.<ref>[http://www.rough-polished.com/en/digest/68330.html Pros and cons of extraterrestrial diamonds] {{Webarchive|url=https://web.archive.org/web/20141222224902/http://www.rough-polished.com/en/digest/68330.html |date=2014-12-22 }}, from "Rough&Polished&ndash;information and analytics on diamond and jewellery markets."</ref>

Additionally, carbon [[polymorphism (materials science)|polymorphs]], a combination of diamond and lonsdaleite even harder than pure lonsdaleite, have been discovered in the crater.<ref>{{cite journal |doi=10.1016/j.crte.2003.07.001|title=A new natural, super-hard, transparent polymorph of carbon from the Popigai impact crater, Russia|journal=Comptes Rendus Geoscience|volume=335|issue=12|pages=889|year=2003|last1=El Goresy|first1=Ahmed|last2=Dubrovinsky|first2=Leonid S|last3=Gillet|first3=Philippe|last4=Mostefaoui|first4=Smail|last5=Graup|first5=Günther|last6=Drakopoulos|first6=Michael|last7=Simionovici|first7=Alexandre S|last8=Swamy|first8=Varghese|last9=Masaitis|first9=Victor L|bibcode=2003CRGeo.335..889E|url=https://comptes-rendus.academie-sciences.fr/geoscience/articles/10.1016/j.crte.2003.07.001/ }}</ref><ref>{{Cite journal|last1=Baek|first1=Woohyeon|last2=Gromilov|first2=Sergey A.|last3=Kuklin|first3=Artem V.|last4=Kovaleva|first4=Evgenia A.|last5=Fedorov|first5=Alexandr S.|last6=Sukhikh|first6=Alexander S.|last7=Hanfland|first7=Michael|last8=Pomogaev|first8=Vladimir A.|last9=Melchakova|first9=Iuliia A.|last10=Avramov|first10=Paul V.|last11=Yusenko|first11=Kirill V.|date=2019-03-13|title=Unique Nanomechanical Properties of Diamond–Lonsdaleite Biphases: Combined Experimental and Theoretical Consideration of Popigai Impact Diamonds|journal=Nano Letters|volume=19|issue=3|pages=1570–1576|doi=10.1021/acs.nanolett.8b04421|pmid=30735045|bibcode=2019NanoL..19.1570B|s2cid=73443676 |issn=1530-6984}}</ref>

== See also ==
* [[List of impact craters on Earth]]
* [[List of possible impact structures on Earth]] 
* {{annotated link|Logancha crater}}

== References ==
{{Reflist}}

== External links ==
* [https://www.unb.ca/passc/ImpactDatabase/ Earth Impact Database]
* [https://web.archive.org/web/20100627071048/http://geology.mines.edu/faculty/Klee/Popigai.pdf About the Popigai impact structure]
* [http://unesdoc.unesco.org/images/0015/001500/150007e.pdf UNESCO Global Geopark Network]
* [https://maps.google.com/maps?q=71.661935,+110.960998&num=1&t=h&vpsrc=6&ie=UTF8&ll=70.670881,99.316406&spn=31.51452,173.144531&z=3&iwloc=A Google Maps]

{{Impact cratering on Earth}}
{{Authority control}}

[[Category:Impact craters of Russia]]
[[Category:Impact craters of the Arctic]]
[[Category:Eocene impact craters]]
[[Category:Priabonian Stage]]
[[Category:Landforms of Krasnoyarsk Krai]]
[[Category:Diamond mines in Russia]]
[[Category:Diamond mines in the Soviet Union]]