Editing Popigai impact structure (section)

{{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 =
| label_position = 
| 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 = 
| province =
| district = 
| 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"/>