Glover Bluff crater is recorded in the Earth Impact Database as less than 500 million years old, exposed, and about 8 km in diameter. The site was first observed by W. C. Alden, in 1918, and was reported on in some depth by Ekern and Thwaites in 1930. According to the Ekern and Thwaites report, the structure is preserved in Cambrian and Ordovician Dolomite and Sandstone. More recent articles mention a quarry currently operating in the central uplift region. A brief review of the articles suggests that quarrying has been going on in the crater for nearly 100 years. The impact origin was confirmed in the 1980s, by the discovery of shatter cones (Read, 1983).
Evidence of Impact Origin
The impact origin of each location listed on this website has been supported by unambiguous diagnostic evidence of hypervelocity impact that has been reported in a scientific (usually peer reviewed) context. Without such evidence, a geological structure is not a confirmed impact crater. This section, which is included for each crater on this website, is not an exhaustive list of such published evidence, but is meant to demonstrate that appropriate work has been done for each listing.
Other significant evidence: breccia, morphology.
Also published as: Glover Bluff Structure, Glover Bluff Disturbance
Bibliography and References:
(If links to articles don't work, don't give up. Try pasting the link shown into a search engine or searching for the article authors, title, or other reference information. If your research leads you to additional scientific references related to this crater, please help improve this resource by sending a note with the new citation(s) to: firstname.lastname@example.org )
Cannon, W. F., Mudrey, M. G. Jr. 1981. The potential for diamond-bearing kimberlite in Northern Michigan and Wisconsin. U.S. Geological Survey Circular 842, 15 pages.
Coleman, L. D. 2001. A Meteorite Crater in the Backyard. Meteorite magazine, Vol. 7, Feb. 2001. pp: 8-11.
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Dietz, R. S. & McHone, J. F. 1984. Shatter Cones: Difinitive Criteria for Meteorite Impact. Meteoritics, Vol. 19, p.221.
Dietz, R. S., McHone, J. F. 1991. Astroblemes recently confirmed with shatter cones (abstract). Meteoritics, v. 26, p. 332.
Ekern, G. L., Thwaites, F. 1930. The Glover Bluff structure, a disturbed area in the Paleozoics of Wisconsin. Transactions of the Wisconsin Academy of Sciences, Arts and Letters, v. 25, pp. 89-97.
Ernst B. and Paulsen T. 1973. New constraints on the timing of deformation at the Glover Bluff structure near Coloma, WI, from a calcite twinning analysis (abstract). Abstracts with Programs - Geological Society of America, Volume 43. No 5. p. 188.
Koenen, K. H., Geophysical studies in south central Wisconsin. Unpublished Master's Thesis, University of Wisconsin, Madison, 44 p. 1956.
Read, W. F. 1983. Shatter cones at Glover Bluff, Wisconsin. Meteoritics, v. 18, no. 3, pp. 241-243.
Read, W. F. 1984. The circular structure at Glover Bluff: What and where it is (abstract). Meteoritics, v. 19, pp. 295-296.
Read, W. F. 1985. Impact bombs in Middle Ordovician marine sediments of southeastern Wisconsin (abstract). 16th Lunar and Planetary Science. pp. 687-688.
Renard G. M. 2011 Ejecta strata of recent origin have been identified in central Wisconsin at Glover Bluff impact site (abstract). Geological Society of America - Abstracts with Programs. Vol. 43, No. 5, p.306