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Beaverhead

 Crater Name  Location  Latitude  Longitude  Diameter (km)  Age (Ma)  Exposed  Drilled  Targed Rock**  Bolid Type***
 Beaverhead  Montana, U.S.A.  N 44° 36'  W 113° 0'  60  ~ 600  Y  N  M  -

Bouguer gravity map of region surrounding the proposed
thrust detached root to the Beaverhead structure, East Idaho.

References

Carr, J., Link, P.K., Geslin, J.K., McCafferty, A., Hargraves,R.B., Sedimentary Breccia Deposited within Eocambrian Beaverhead Impact Crater, Lost River Range, Idaho, GSA Abstracts with Programs, 1996, Session 92. P. 230. 1996.
Cockell, C. S., Lee, P., The Biology of Impact Craters - a review. Biol. Rev., 77, P. 279 - 310. 2002.
Dietz, R. S., McHone, J. F., Astroblemes recently confirmed with shatter cones (abstract). Meteoritics, v. 26, p. 332. 1991.
Fiske, P. S., The preservation of impact features in orogenic belts: The case of the Beaverhead structure, SW Montana (abstract). 1993 Fall Meeting, AGU, v. Fall, p. 387. 1993.
Fiske, P. S., Hargraves, R.B., Onstott, T.C., Kkoeberl, C. and Hougen,S.B., Pseudotachylites of the Breaverhead impact structure: Geochemical, geochronological, petrographic, and field investigations. Geological Society of America Special Paper 293, pp. 163-176. 1994.
Fiske, P. S., Hougen, S.B. and Hargraves,R.B., Breccia dikes from the Beaverhead impact structure, southwest Montana (abstract). International Conference on Large Meteorite Impacts and Planetary Evolution, LPI Contribution No. 790, pp. 26. 1992.
Geissman J. W., Brearley A. J., Housen B. A., Fiske P. S., Hargraves R., The Beaverhead Impact Structure - Discovery and Investigation of an Allocthonous Impact Structure in SW Montana, 2003.
Glikson, A. Y., Mega-impacts and mantle-melting episodes: tests of possible correlations. AGSO Journal of Australian Geology & Geophysics, v. 16, pp. 587-607. 1996.
Hargraves, R. B., Christiansen, P P., Cullicott, C E., Deffeyes, K S., Fiske, P S. and Hougen,S., Shatter cones and shocked rocks in southwestern Montana: The Beaverhead impact structure. Geology, v. 18, pp. 832-834. 1990.
Hargraves, R. B., White, J. C., Micro-Shock deformation adjacent to the surface of shatter cones from the Beaverhead Impact Structure, Montana, The Journal of Geology, v. 104, p. 233-238. 1996.
Hargraves, R. B., Kellogg, K.S., Fiske, P.S. and Hougen,S.B., Allochthonous impact-shocked rocks and superimposed deformations at the Beaverhead site in southwest Montana. Geological Society of America Special Paper 293, pp. 225-235. 1994.
Hargraves, R. B., Where's the Beaverhead beef? (abstract). International Conference on Large Meteorite Impacts and Planetary Evolution, LPI Contribution No. 790, pp. 35-36. 1992.
Kellogg, K. S., Snee, L. W. , Unruh, D. M., The Mesoproterozoic Beaverhead Impact Structure and Its Tectonic Setting, Montana-Idaho: 40Ar/ 39Ar and U-Pb Isotopic Constraints. The Journal of Geology, Vol. 111, P. 639 - 652. 2003.
Koeberl, C., Fiske, P. S., Beaverhead impact structure, Montana: Geochemistry of impactites and country rock samples (abstract). Meteoritics, v. 26, pp. 358-359. 1991.
Lee, P., Kay, R. W., Search for a meteoritic component at the Beaverhead impact structure, Montana (abstract). International Conference on Large Meteorite Impacts and Planetary Evolution, LPI Contribution No. 790, pp. 47. 1992.
McCafferty, A. E., Assessing the presence of a buried meteor impact crater using geophysical data, south-central Idaho (abstract). Thesis, Colorado School of Mines. 1995.
McCafferty, A. E., Hargraves, R B., Roddy, D J. and Kellogg,K S., Does the root of the Beaverhead impact structure have a geophysical signature? (abstract). 1993 Fall Meeting, AGU, v. Fall, p. 223. 1993.
Merrill J. C., The formation of Leaton Gulch, Grouse Peak, Pahsimeroi Mountains, Custer County, Idoho, Neoproterozoic conglomerates and breccias and their relation to the Beaverhead impact Structure, 2010.
* 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)