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Earth Impact Database Sorted by : | Name | Diameter | Age |



Crater Name
Diameter (km)
Age (Ma)*
Target Rock**
Bolide Type***
N 58° 46'
E 17° 25'
~ 455


Floden, T., Tunander, P. and Wickman,F.E., The Tvaren Bay structure, an astrobleme in southeastern Sweden. Geologiska Foreningens I Stockholm Forhandlingar, v. 108, p. 225-234. 1986.
Frisk, A.M. and Ormo, J. Facies distribution of post-impact sediments in the Ordovician Lockne and Tvaren impact craters; indications for unique impact-generated environments. Meteoritics & Planetary Science, vol. 42, pp.1971. 2007.
Frisk, A.M., and Harper, D.A.T. Late Ordovician brachiopod distribution and ecospace partitioning in the Tvaren Crater system, Sweden. Palaeogeography, Palaeoclimatology, Palaeoecology, vol. 369, pp.114. 2013.
Frisk, A.M., and Harper, D.A.T. Palaeoenvironmental aspects of Late Ordovician Sericoidea shell concentrations in an impact crater, Tvaren, Sweden. Lethaia, vol.44, pp.383. 2011.
Grahn, Y., Nolvak, J and Paris,F., Precise chitinozoan dating of Ordovician impact events in Baltoscandia, Journal of Micropalaeontology, v.15, p.21-35. 1996.
Grahn, Y., Nolvak, J., Chitinozoan dating of Ordovician impact events in Sweden and Estonia. A preliminary note. Geologiska Föreningens I Stockholm Förhandlingar, v. 115, pp. 263-264. 1993.
Henkel, H., Ekneligoda, T.C., and Aaro, S. The extent of impact induced fracturing from gravity modeling of the Granby and Tvaren simple craters. Tectophysics, vol.485, pp.290. 2010.
Henkel, H., Pesonen, L. J., Impact craters and craterform structures in Fennoscandia. Tectonophysics, v. 216, pp. 31-40. 1992.
Lindström, M., Flodén, T., Grahn, Y. and Kathol,B., Post-impact deposits in Tvären, a marine Middle Ordovician crater south of Stockholm, Sweden. Geological Magazine, v. 131, p. 91-103. 1994.
Lindström, M., Ormö, J., Sturkell, E.F.F. and Törnberg,R., Geological information from Ordovician marine impact craters (abstract). GFF, v. 118, pp. A99-A100. 1996.
Lindström, M., Sturkell, E. F. F., Geology of the early Palaeozoic Lockne impact structure, central Sweden. Tectonophysics, v. 216, pp. 169-185. 1992.
Ormö J., Blomqvist, G., Magnetic modelling as a tool in the evaluation of impact structures, with special reference to the Tvären Bay impact crater, SE Sweden. Tectonophysics, v. 262, pp. 291-300. 1996.
Ormö, J., Blomqvist, G., Magnetic modelling as a tool in the evaluation of impact structures, with special reference to the Tvaren Bay impact crater, SE Sweden, Tectonophysics 262, 291-300. 1996.
Ormö, J., Blomqvist, G., Magnetic Modelling as a Tool in the Evaluation of Impact Structures, with Special Reference to the Tvaren Bay Impact Crater, SE Sweden, Tectonophysics v. 262 pp. 291-300. 1996.
Ormö, J., Lindstrom, M., When a cosmic impact strikes the sea bed, Geol. Mag. V.137(1), p.67-80. 2000.
Ormö, J., The pre-impact Ordovician stratigraphy of the Tvaren Bay impact structure, SE Sweden, GFF 116, 139-144. 1994.
Ormö, J., The pre-impact Ordovician stratigraphy of the Tvären Bay impact structure, SE Sweden. GFF, v. 116, pp. 139-144. 1994.
Ormö, J., Törnberg, R., The Tvären Bay impact crater - pre-impact straitigraphy and shocl metamorphosis. Second International Conference. Impact Cratering and Evolution of Planet Earth. The Identification and Characterization of Impacts. 1994.
Ormoe, J., Hill, A.C., and Self-Trail, J.M. A chemostratigraphic method to determine the end of impact-related sedimentation at marine-target impact craters (Chesapeake Bay, Lockne, Tvaren). Meteoritics & Planetary Science, vol.45, pp.1206. 2010.
Tornberg, R., and Sturkell, E.F.F. Density and magnetic susceptibility of rocks from the Lockne and Tvaren marine impact structures. Meteoritics & Planetary Science, vol.40, pp.639. 2005.
Törnberg, R., Frequency distribution of shock metamorphic effects and dimensioning of the marine impact crater of the Tvären Bay, Sweden (abstract). European Science Foundation, Third International Workshop. Shock Wave Behaviour of Solids in Nature and Experiments, Limoges, France. 1994.
Törnberg, R., Impact-related resurge sedimentology as exemplified by the Lockne, Tvären and Kärdla structures (abstract). GFF, v. 118, p. A102. 1996.
Wallin, Å., Hagenfeldt, S. E., Biostratigraphical investigation of Middle Ordovician acritarchs in the post-impact sequence in the Tvären-2 core, Sweden. GFF, v. 118, pp. 79-82. 1996.
Wickman, F. E., Possible impact structures in Sweden. A. Boden and K.G. Eriksson, eds., in Deep Drilling in Crystalline Bedrock, Springer-Verlag, Berlin, p. 298-327. 1988.


* pre-1977 K-Ar, Ar-Ar and Rb-Sr ages recalculated using the decay constants of Steiger and Jager (1977) Ages in millions of years (Ma) before present.

** Abbreviations: C - Crystalline Target; C-Ms - Metasedimentary Target; M - Mixed Target (i.e.sedimentary strata overlying crystalline basement); S - sedimentary target (i.e. no crystalline rocks affected by the impact event). From Osinski. G. R., Spray J. G., and Grieve R. A. F. 2007. Impact melting in sedimentary target rocks: A synthesis. In The Sedimentary Record of Meteorite Impacts, Geological Society of America Special Paper. Editors: Evans K. Horton W., King D., Morrow J., and Warme J. Geological Society of America: Boulder, in press.

From Koeberl,C. Identification of meteoritic components in impactites. 1998, Koeberl, C. The Geochemistry and Cosmochemistry of Impacts. 2007 and PASSC Files. (IAB, IIIAB, IIIB, IIID - Iron Meteorite)



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