Earth:Lake Cheko

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Short description: Lake in Krasnoyarsk Krai, Russia
Lake Cheko
Lake Cheko is located in Russia
Lake Cheko
Lake Cheko
Location in Russia
Lake Cheko is located in Krasnoyarsk Krai
Lake Cheko
Lake Cheko
Lake Cheko (Krasnoyarsk Krai)
Locationnear Podkamennaya Tunguska River, Siberia
Coordinates [ ⚑ ] : 60°57′50″N 101°51′36″E / 60.964°N 101.86°E / 60.964; 101.86
Native nameЧеко  (Russian)
Basin countriesRussia
Average depth50 metres (160 ft)

Lake Cheko (Russian: Чеко) is a small freshwater lake in Siberia, near the Podkamennaya Tunguska River, in what is now the Evenkiysky District of the Krasnoyarsk Krai.

Dimensions and environs

Lake Cheko is a small bowl-shaped lake. It is about 500 metres (1,600 ft) long, 300 metres (980 ft) wide and 50 metres (160 ft) deep.[1][2]

In the lake flows the Kimchu River (Russian: кимчу), which flows into the Chunya River (Russian: Чуня), which in turn flows into the Podkamennaya Tunguska.[3][4][5]

Lake Cheko is roughly 8 kilometres (5.0 mi) north-northwest[6] of the epicenter of the Tunguska event.[7] The lake is inside the blast zone,[8] and in the probable direction of whatever caused the Tunguska event.[9]

Proposed impact origin

A 1961 investigation estimated the age of the lake to be at least 5000 years, based on meters-thick silt deposits on the lake bed.[10] However, Luca Gasperini and his co-investigators working in 2008 concluded that the sediments, isotopes, and pollen "suggest that Lake Cheko formed at the time of the Tunguska Event" and thus was only 100 years old.[11][12][13] They also reported that acoustic-echo soundings revealed a conical shape for the lake bed, which they interpreted as consistent with an impact crater. They said the lake's long axis points to the hypocenter of the Tunguska explosion, about 7.0 km away,[14] and they interpreted magnetic readings as indicative of a possible meter-sized chunk of rock below the lake's deepest point, that they suggested could be a meteorite.

In 2008, a BBC News story on the 100th anniversary of the Tunguska Event mentioned that researchers at Imperial College London had pointed out that many of the trees surrounding the lake are older than 100 years, which suggests that the lake could not have been created by an impact in 1908.[15] The researchers also pointed out other problems, including the morphology of the lake and the surrounding terrain, and the lack of impactor debris and ejecta, noting that the characteristics of the impactor required by the impact theory are inconsistent with existing models of the known features of the event. Other researchers have said it is unlikely that a stony meteorite in the right size range would have the mechanical strength necessary to survive atmospheric passage intact, and yet still retain a velocity large enough to excavate a crater that size on reaching the ground.[16]

In 2017, Russian scientists reported isotope evidence showing the lake is older than the Tunguska Event.[17]

See also

References

  1. ↑ Chandler, David (27 June 2007). "Siberian lake could have been made by asteroid blast". News@nature. doi:10.1038/news070625-8. https://www.nature.com/news/2007/070627/full/news070625-8.html. Retrieved 14 May 2018. 
  2. ↑ Cristina Valsecchi, Maria (November 7, 2007). "Crater From 1908 Russian Space Impact Found, Team Says". National Geographic. https://news.nationalgeographic.com/news/2007/11/071107-russia-crater.html. Retrieved 14 May 2018. 
  3. ↑ Florenskiy, K P (May 1962). "PRELIMINARY RESULTS FROM THE 1961 COMBINED TUNGUSKA METEORITE EXPEDITION". Meteoritica. http://198.74.48.154/bobk/tungmet.html. Retrieved 18 May 2018. 
  4. ↑ Kulik, L. (1935). "On the Fall 'Of the Podkamennaya Tunguska Meteorite In 1908". Contributions of the Society for Research on Meteorites 1: 35–39. doi:10.1111/j.1945-5100.1935.tb00263.x. 
  5. ↑ "Vanavara, discovering Siberian meteor mystery". Russia Beyond. January 20, 2014. https://www.rbth.com/travel/2013/03/22/vanavara_discovering_siberian_mystery. Retrieved 18 May 2018. 
  6. ↑ Dockweiler, T. (July 2007). "Cosmic Collision: The Lake Cheko — Tunguska 1908 Bolide Event". Science Newsletter. http://tunguska.tsc.ru/f/4804/MainPart/newsletter.pdf. Retrieved 19 May 2018. 
  7. ↑ "The Tunguska Mystery--100 Years Later". https://www.scientificamerican.com/article/the-tunguska-mystery-100-years-later/. The Tunguska Mystery--100 Years Later
  8. ↑ "The Tunguska event and Cheko lake origin: Dendrochronological analysis". https://www.researchgate.net/figure/Geological-map-of-the-area-Surrounding-Cheko-lake_fig3_267638609?_sg=aN8Yr7IDlOPIDQP9HSmAyShXirNf4RROQZ5bueAD_ekS65stdVRo9RK7YELvQ80d2cGVI1LQOW4x6tYmnys_Ig. 
  9. ↑ "Magnetic and seismic reflection study of Lake Cheko, a possible impact crater for the 1908 Tunguska Event". May 2012. https://www.researchgate.net/figure/left-Landsat-image-of-the-Tunguska-area-with-indicated-the-pattern-of-trees-flattened_fig1_230602622. Retrieved 19 May 2018. 
  10. ↑ Florenskiy, K. P. (1963). "Preliminary results from the 1961 combined Tunguska meteorite expedition". Meteoritica 23: 3–29. http://abob.libs.uga.edu/bobk/tungmet.html. Retrieved 2007-06-26. 
  11. ↑ Gasperini, L. (2001). "Geophysical/sedimentological study of a lake close to the centre of the great 1908 Siberian (Tunguska) Explosion". NGF Abstracts and Proceedings (1): 29–30. http://www-th.bo.infn.it/tunguska/GasperiniSvalbard.pdf. Retrieved 2008-05-27. 
  12. ↑ Gasperini, L. et al. (April 2008). "Reply - Lake Cheko and the Tunguska Event: impact or non-impact?". Terra Nova 20 (2): 169–172. doi:10.1111/j.1365-3121.2008.00792.x. Bibcode: 2008TeNov..20..169G. 
  13. ↑ Rincon, Paul (2007-06-26). "Team makes Tunguska crater claim". BBC News. http://news.bbc.co.uk/2/hi/science/nature/6239334.stm. Retrieved 2013-02-15. 
  14. ↑ Gasperini, L. (June 2008). "The Tunguska Mystery". Scientific American 298 (6): 80–86. doi:10.1038/scientificamerican0608-80. PMID 18642546. Bibcode: 2008SciAm.298f..80G. 
  15. ↑ Rincon, Paul (2008-06-30). "Fire in the sky: Tunguska at 100". BBC News. http://news.bbc.co.uk/1/hi/sci/tech/7470283.stm. Retrieved 2008-07-01. 
  16. ↑ Collins, G. S. et al. (2008). "Evidence that Lake Cheko is not an impact crater". Terra Nova 20 (2): 165–168. doi:10.1111/j.1365-3121.2008.00791.x. Bibcode: 2008TeNov..20..165C. 
  17. ↑ Rogozin, D. Y.; Darin, A. V.; Kalugin, I. A.; Melgunov, M. S.; Meydus, A. V.; Degermendzhi, A. G. (October 2017). "Sedimentation rate in Cheko Lake (Evenkia, Siberia): New evidence on the problem of the 1908 Tunguska Event". Doklady Earth Sciences 476 (2): 1226–1228. doi:10.1134/S1028334X17100269. Bibcode: 2017DokES.476.1226R. 

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