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Rock Elm

 Crater Name  Location  Latitude  Longitude  Diameter (km)  Age (Ma)  Exposed  Drilled  Target Rock**  Bolide Type***
 Rock Elm  Wisconsin, U.S.A.  N 44° 43'  W 92° 14'  6  < 505  -  -  S  -

References
Arana, A., and Cavosie, A. J. 2014. A study of shocked quartz in breccia from the Rock Elm impact structure. 45th Lunar and Planetary Science Conference, abstract #2185.
Cavosie, A. J., Erickson, T. M., and Timms, N. E. 2014. Reidite and shock-twinned zircon in polymict breccia from the Ordovician Rock Elm impact structure, USA. Geological Society of America Abstracts with Programs, 46(6).
Cavosie, A. J., Roig, C. I., McDougal, D. J., Ushikubo, T., Spicuzza, M. J., Fournelle, J., … Mattson, C. 2013. The Sedimentary Record of a Small, Deeply Eroded Impact Structure: A Search for Detrital Shocked Minerals and Extraterrestrial Chromites in Sediments Eroded from the Ordovician Rock Elm Impact Structure (USA). 44th Lunar and Planetary Science Conference, abstract #2028.
Cordua W.S., An Ordovician cryptoexplosion structure from near Rock Elm, Pierce county, Wisonsin, 1983.
Cordua, W. S. 1985. The Rock Elm Structure, Pierce County, Wisconsin, a possible cryptoexplosion structure. Geology, 13, 372–374.
Cordua, W. S. 1987. The Rock Elm Disturbance, Pierce County, Wisconsin. Minnesota Geological Survey Guidebook Series #15, 123–152.
French, B. M., and Cordua, W. S. 1999. Intense fracturing of quartz at the Rock Elm (Wisconsin) “cryptoexplosion” structure: evidence for meteorite impact. 30th Lunar and Planetary Science Conference, abstract #1123.
Roig, C. I., Cavosie, A. J., McDougal, D., Cordua, W. S., and Mattson, C. 2013. Detrital shocked quartz in modern sediments eroded from the Rock Elm impact structure, Wisconsin, USA. 44th Lunar and Planetary Science Conference, abstract #2685.
* 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)