Glover Bluff, North Rim
N 43° 58.429 W 089° 32.081
16T E 296692 N 4872088
The Glover Bluff Crater is located near Coloma, WI. It is estimated to be 500 million years old with the original crater size ranging from 5 to 13 miles.
Waymark Code: WM2K7K
Location: Wisconsin, United States
Date Posted: 11/14/2007
Views: 128
The majority of the crater is on private land, but the visitor can get a clear view of the three hilly areas from Dakota Rd, 4th Rd, and 5th Rd.
From the Meteorites Articles web site:
The Glover Bluff meteorite impact crater in is southeastern Wisconsin close to Madison in Marquette County. This impact site consists of three exposed hilly areas that come ~ 110-feet above the surrounding countryside. Discovered in 1980 below the hills, was Ordovician dolomite and Shattercones, proving its meteortic orgin. Estimates place the impact about 500 million years ago with the original crater size ranging from 5 to 13 mile! This breccia material was found in the dolomite area. It has a nice light red matrix that becomes bright red if polished. Little testing has been done in the area, and it is now a quarry being destroyed. Meanwhile, little information is known about this breccia looking rock. A great example of the lack of research on this crater is NASA's "Bibliography of Terrestrial Impact Structures", over 530 pages and telephone book size refence book to several thousands of impact research papers. It only list 4 papers for Glover Bluff and only one mentions meteorite relation, other references predate impact acceptence. The only other reference to this site I could find was in Paul Hodge's Meteorite Craters and Impact Structures of the Earth, Cambridge University Press, and in Meteortics, v.18. no. 3. which does not mention much. This location has two types of breccia that has been collected lately. A red type and a light yellow type. Cut by fellow International Meteorite Collector Association member Ron Hartman.
photo from the Meteorites Articles web site