Popigai crater

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Popigai crater
Popigai crater russia.jpg
Landsat image of Popigai crater
Impact crater/structure
ConfidenceConfirmed
Diameter90 km (56 mi)
Impactor diameter5 ± 2 kilometers (3.1 ± 1.2 mi)
Age35.7 ± 0.2 Ma
Late Eocene
ExposedYes
DrilledYes
Bolide typeH chondrite [1]
Location
Coordinates71°39′N 111°11′E / 71.650°N 111.183°E / 71.650; 111.183Coordinates: 71°39′N 111°11′E / 71.650°N 111.183°E / 71.650; 111.183
Country Russia
StateKrasnoyarsk
Popigai crater is located in Russia
Popigai crater
Location of the crater in Russia

The Popigai crater (or astrobleme) in Siberia, Russia, is tied with the Manicouagan Crater as the fourth largest verified impact crater on Earth.[2][3] A large bolide impact created the 100-kilometre (62 mi) diameter crater approximately 35 million years ago during the late Eocene epoch (Priabonian stage).[4][5] It is conjectured that it may have influenced the Eocene–Oligocene extinction event.[6]

The crater is 300 km (190 mi) east from the outpost of Khatanga and 880 km (550 mi) northeast of the city of Norilsk. It is designated by UNESCO as a Geopark, a site of special geological heritage.[7] There is a small possibility that the Popigai impact crater may have formed simultaneously with the approximately 35-million-year-old Chesapeake Bay and Toms Canyon impact craters.[4]

For decades the Popigai crater has fascinated paleontologists and geologists, but the entire area was completely off limits because of the diamonds found there and the mines constructed by gulag prisoners under Stalin. However, a major investigatory expedition was undertaken in 1997, which greatly advanced understanding of the enigmatic structure.[7] The impactor in this event has been identified as either an 8 km (5.0 mi) diameter chondrite asteroid, or a 5 km (3.1 mi) diameter stony asteroid.

The shock pressures from the impact instantaneously transformed graphite in the ground into diamonds within a 13.6 km (8.5 mi) radius of the impact point. These diamonds are usually 0.5 to 2 mm (0.020 to 0.079 in) in diameter, though a few exceptional specimens are 10 mm (0.39 in) in size. The diamonds not only inherited the tabular shape of the original graphite grains but they additionally preserved the original crystals' delicate striations.[7]

Diamond deposits[edit]

Popigai diamonds are about 1 mm in size and consist of nanodiamond agglomerates.[8]

Most modern industrial diamonds are produced 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.[9] Many of the diamonds at Popigai contain crystalline lonsdaleite, an allotrope of carbon that has a hexagonal lattice.[10] Pure, laboratory-created lonsdaleite is up to 58% harder than ordinary diamonds.[11][9] 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.[10] They may have industrial uses but are unsuitable as gems.[12]

Additionally, carbon polymorphs even harder than lonsdaleite have been discovered in the crater.[13]

See also[edit]

References[edit]

  1. ^ Schmitz, Birger; Boschi, Samuele; Cronholm, Anders; Heck, Philipp R.; Monechi, Simonetta; Montanari, Alessandro; Terfelt, Fredrik (2015). "Fragments of Late Eocene Earth-impacting asteroids linked to disturbance of asteroid belt". Earth and Planetary Science Letters. 425: 77–83. Bibcode:2015E&PSL.425...77S. doi:10.1016/j.epsl.2015.05.041. ISSN 0012-821X.
  2. ^ "Popigai". Earth Impact Database. University of New Brunswick. Retrieved 2017-10-09.
  3. ^ Masaitis, Victor L. (2003). Popigai Crater: General Geology. Springer. pp. 81–85. ISBN 978-3-540-43517-4.
  4. ^ a b Deutsch, Alexander; Christian Koeberl (2006). "Establishing the link between the Chesapeake Bay impact structure and the North American tektite strewn field: The Sr-Nd isotopic evidence" Check |url= value (help). Meteoritics & Planetary Science. 41 (5): 689–703. Bibcode:2006M&PS...41..689D. doi:10.1111/j.1945-5100.2006.tb00985.x. Retrieved 2008-06-16.[permanent dead link]
  5. ^ Armstrong, Richard; S. Vishnevsky; C. Koeberl (2003). U-Pb Analysis of zircons from the Popigai impact structure, Russia: First Results. Springer. pp. 99–116. ISBN 978-3-540-43517-4.
  6. ^ "Russia's Popigai Meteor Crash Linked to Mass Extinction". June 13, 2014.
  7. ^ a b c Deutsch, Alexander; V.L. Masaitis; F. Langenhorst; R.A.F. Grieve (2000). "Popigai, Siberia—well preserved giant impact structure, national treasury, and world's geological heritage". Episodes. 23 (1): 3–12. Retrieved 2014-04-06.[permanent dead link]
  8. ^ Ohfuji, Hiroaki; Irifune, Tetsuo; Litasov, Konstantin D.; Yamashita, Tomoharu; Isobe, Futoshi; Afanasiev, Valentin P.; Pokhilenko, Nikolai P. (2015). "Natural occurrence of pure nano-polycrystalline diamond from impact crater". Scientific Reports. 5: 14702. Bibcode:2015NatSR...514702O. doi:10.1038/srep14702. PMC 4589680. PMID 26424384.
  9. ^ a b "Diamonds Beneath the Popigai Crater -- Northern Russia". geology.com. 23 September 2012. Retrieved 24 September 2012.
  10. ^ a b "Russia declassifies deposit of impact diamonds". ITAR-TASS. 17 September 2012. Retrieved 17 September 2012.
  11. ^ Pan, Zicheng; Sun, Hong; Zhang, Yi & Chen, Changfeng (2009). "Harder than Diamond: Superior Indentation Strength of Wurtzite BN and Lonsdaleite". Physical Review Letters. 102 (5): 055503. Bibcode:2009PhRvL.102e5503P. doi:10.1103/PhysRevLett.102.055503. PMID 19257519. Lay summaryPhysorg.com (12 February 2009).
  12. ^ Pros and cons of extraterrestrial diamonds Archived 2014-12-22 at the Wayback Machine, from "Rough&Polished–information and analytics on diamond and jewellery markets."
  13. ^ El Goresy, Ahmed; Dubrovinsky, Leonid S; Gillet, Philippe; Mostefaoui, Smail; Graup, Günther; Drakopoulos, Michael; Simionovici, Alexandre S; Swamy, Varghese; Masaitis, Victor L (2003). "A new natural, super-hard, transparent polymorph of carbon from the Popigai impact crater, Russia". Comptes Rendus Geoscience. 335 (12): 889. Bibcode:2003CRGeo.335..889E. doi:10.1016/j.crte.2003.07.001.

External links[edit]