Tvären

Tvären is a circular bay close to Studsvik, Sweden. The bay lies above an ancient buried impact crater about 2 km in diameter. The crater is estimated to be about 455 million years old (Upper Ordovician).^[1]

Asteroid 7771 Tvären is named after the bay.

References

↑ "Tvären". Earth Impact Database. University of New Brunswick. Retrieved 2009-08-20.

Coordinates: 58°46′N 17°25′E / 58.767°N 17.417°E / 58.767; 17.417

Impact cratering on Earth

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Confirmed ≥20 km diameter	Acraman Amelia Creek Araguainha Beaverhead Boltysh Carswell Charlevoix Chesapeake Bay Chicxulub Clearwater East & West Gosses Bluff Haughton Kamensk Kara Karakul Keurusselkä Lappajärvi Logancha Manicouagan Manson Mistastin Mjølnir Montagnais Morokweng Nördlinger Ries Obolon' Popigai Presqu'île Puchezh-Katunki Rochechouart Saint Martin Shoemaker Siljan Ring Slate Islands Steen River Strangways Sudbury Tookoonooka Tunnunik Vredefort Woodleigh Yarrabubba

Topics	Alvarez hypothesis Breccia Coesite Complex crater Cretaceous–Paleogene boundary Cryptoexplosion Ejecta blanket Impact crater Impact structure Impactite Late Heavy Bombardment Lechatelierite Meteorite Moldavite Ordovician meteor event Planar deformation features Shatter cone Shock metamorphism Shocked quartz Stishovite Suevite Tektite

Research	Baldwin, Ralph Belknap Barringer, Daniel Barringer Medal Chao, Edward C T Dietz, Robert S Hartmann, William K Melosh, H Jay Ryder, Graham Schultz, Peter H Shoemaker, Eugene Earth Impact Database Impact Field Studies Group Lunar and Planetary Institute Traces of Catastrophe

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