by: Charles O’Dale

*In my articles I use the term crater to define a circular impact depression and the term structure to define an impact crater that is severely altered by erosion.



    • Alphabetically;
    • Diameter;
    • Confirmed; an impact site with documented shock features and/or meteoritic material and/or observed fall.
    • Probable; structural, geological and geophysical studies established reasonable evidence, possibly with unconfirmed reports of shock features in abstracts, but the definite shock features and/or meteoritic material is not well documented.
    • Proposed; some structural, geological and/or geophysical evidence exists but the impact origin is still highly uncertain for the lack of data.
    • Improbable; observations of the structure and/or geological context suggest a non-impact origin but alternative interpretation has not been well established.
    • Non-Impact; a non-impact origin has been well documented.
    • Extinction;


1 Dence, Michael R. Structural evidence from shock metamorphism in simple and complex impact craters: Linking observations to theory. Meteoritics & Planetary Science 39. Nr 2, 267-286 (2004).

2 Grieve R.A.F., Impact structures in Canada, Geological Association of Canada, 2006.

3 Spray J.G. et al. A marine magnetic study of the Ile Rouleau impact structure, Lake Mistassini, Quebec Canada. Meteoritics, 70th Annual Meeting (2007).

4 Eugene M. Shoemaker, Bryan J. Kriens, Ken E. Herkenhop, GEOLOGY OF THE UPHEAVAL DOME IMPACT STRUCTURE, SOUTHEAST UTAH. Journal of Geophysical Research–Planets, April 16, 1998.

5 Grieve R.A.F. and Head J.W. The Manicouagan impact structure: An analysis of its original dimensions and form. Journal of Geophysical Research 88:A807-A818 (1983).

6 French, B.M. Traces of Catastrophe, Lunar and Planetary Institute, 1998

7 Cordua, W. S., “The Rock Elm Structure, Pierce County, Wisconsin, a possible cryptoexplosion structure”, Geology, vol. 13, p. 372-374. 1985.

8Donofrio, Richard R., IMPACT CRATERS: IMPLICATIONS FOR BASEMENT HYDROCARBON PRODUCTION. Journal of Petroleum Geology, 3, 3, pp. 279-302, 1981.

“We, all of us, are what happens when a primordial mixture of hydrogen and helium evolves for so long that it begins to ask where it came from.”
Jill Tarter