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Lake Lappajärvi

Lake Lappajärvi
Lappajärvi from satellite.png
Lappajärvi is the largest lake near the lower right corner.
LocationLappajärvi, Finland
Coordinates63°12′N 023°42′E / 63.200°N 23.700°E / 63.200; 23.700Coordinates: 63°12′N 023°42′E / 63.200°N 23.700°E / 63.200; 23.700
Typeimpact crater
Primary outflowsÄhtävänjoki
Basin countriesFinland
Surface area145.49 km2 (56.17 sq mi)[1]
Max. depth36 m (118 ft)
Surface elevation69.5 m (228 ft)[1]
Islands56 (Kärnä)
References[1]

Lappajärvi is a lake in Finland, in the municipalities of Lappajärvi, Alajärvi and Vimpeli.[1] It is formed in a 23 km (14 mi) wide, partly eroded meteorite impact crater.[2] The lake is part of Ähtävänjoki (Swedish: Esse å) basin together with Lake Evijärvi that is located downstream (north) of it.

The Lappajärvi impact structure is estimated to be 77.85 ± 0.78 million years old (Campanian age of the Late Cretaceous time period).[3] Experts working on Finland's Olkiluoto nuclear waste repository project have studied Lake Lappajärvi to help them project how Finnish landscapes might look one million years in the future and beyond.[4]

An island in the middle of the lake, Kärnänsaari (Kärnä Island), gives the name to the black impact melt rock (impactite) found there, locally called kärnäite.[5]

The towns on the shore are Lappajärvi and Vimpeli. Although not very near any, the nearest major city is Seinäjoki.

Earlier the lake was thought to have been an ancient volcano crater. In 1967, Swedish geologist Nils Bertil-Svensson examines kärnäite samples, and his article that Lappajärvi is a possible impact crater was published in Nature journal in February 1968. [6]

Gallery

See also

References

  1. ^ a b c d "Finnish lakes larger than 40 square kilometers". Finnish Environment Institute. Archived from the original on 2011-07-25.
  2. ^ "Lappajärvi". Earth Impact Database. Planetary and Space Science Centre University of New Brunswick Fredericton. Retrieved 2009-05-24.
  3. ^ Kenny, G.G.; Schmieder, M.; Whitehouse, M.J.; Nemchin, A.A.; Morales, L.F.G.; Buchner, E.; Bellucci, J.J.; Snape, J.F. (2019). "A new U-Pb age for shock-recrystallised zircon from the Lappajärvi impact crater, Finland, and implications for the accurate dating of impact events". Geochimica et Cosmochimica Acta. 245: 479–494. Bibcode:2019GeCoA.245..479K. doi:10.1016/j.gca.2018.11.021.
  4. ^ Ialenti, Vincent (5 July 2016). "Craters & Mudrock: Tools for Imagining Distant Future Finlands". The Long Now Foundation.
  5. ^ "Archived copy". Archived from the original on 2012-07-31. Retrieved 2012-04-09.CS1 maint: archived copy as title (link)
  6. ^ Nature.com − Lake Lappajärvi, Central Finland: a Possible Meteorite Impact Structure (February 3, 1968)

External links


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