by: Charles O’Dale


The scientific study of impact structures began only about 50 years ago. I’m dating myself, but that was about the time my interest in impact craters started. Like any kid, I spent hours looking at the craters on the Moon through my old telescope. Would I ever get a chance to explore a crater?

Well since retirement, I have combined my hobbies of astronomy, geology and flying to explore impact craters and structures in North America from the air and ground.

I flew my airplane (a C177B – GOZooM) to Puerto Rico to explore a crater only to find that someone had built a radio telescope in it!

You may think that the natural geological forces on our planet would have destroyed any features of impact craters. But, in some instances, these forces have “cross sectioned” the craters to ease our study. I have found the geology in these craters and structures fascinating!

This is me “on the job” exploring impact craters, this time at the Barringer Impact Crater.

While studying the physics of impact crater sites, I have found that circular geological features can also be produced by a number of geological processes.

Halliday I., and Griffin, A.A. 1964:  Application of the scientific method to problems of crater recognition  Meteoritics, vol. 2, No. 2.

These geological processes may include igneous activity (diatremes,  maars, calderas, volcanoes, or syenite/plutons), dissolution and collapse of salt or carbonate rocks by groundwater (dolines), salt or shale diapirism, regional tectonism (circular fold-interference patterns or stratified circular features), glaciation (kettle holes), carbonate mounds, and by meteorite impacts (Stewart 2003).

Stewart S. A. 2003: How will we recognize buried impact craters in terrestrial sedimentary basins? Geology 31:929–932.

This is me fulfilling a lifelong dream – standing on the rim of the Pingualuit crater!

“Civilization exists by geological consent …. subject to change without notice.”

– W. Durant –

My science background plus the experience that I have gleaned from my past profession of semiconductor failure analysis has given me the incentive to document my analysis of these craters and structures. I encourage anyone to please contact me if they note any errors that I may have made in my documentation or if they have something to add.(A few of my expeditions actually resulted from suggestions made from readers of this site).

Many of the other exploration trips that I have made in GOZooM and on foot can be viewed here.

Unless otherwise indicated, all of the aerial images my web site were taken from my chariot “GO ZooM”. FYI, a report on one of our crater exploration trips can be viewed here: Part 1 & Part 2.

If you ever find yourself in Ottawa, please come to one of the monthly meetings of the Ottawa Centre,  Royal Astronomical Society of Canada.

“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


The “Changing Earth” section of the Dynamic Earth Museum at Science North Sudbury is presenting my images of the Manicouagan, Pingualuit (Chubb) and Barringer meteorite craters that I have documented on my expeditions. This is me with a smug look on my face beside the poster.

“How bright and beautiful a comet is as it flies past our planet
provided it does fly past it”

Comet Hyakutake, taken by Peter Ceravolo March 17, 1996 with film. Later processed by Debra Ceravolo.

“All things originate from one another
and vanish into another
… according to time”
CRATER URL References

For the complete physics of impact crater formation I recommend the following references:


Baldwin, R.B. 1963, The Measure of the Moon, Astronomical Journal 69.

Beals, C. S., 1968. On the possibility of a catastrophic origin for the great arc of eastern Hudson Bay.

Beals, C.S. & Halliday, I. 1967: Impact Craters of the Earth and Moon, Journal of the Royal Astronomical Society of Canada, Vol. 61, p.295.


Caty, J.L. et al, 1976, A new astrobleme: Ile Rouleau structure: Canadian Journal of Earth Sciences, v.13.

Brent Dalrymple,Radiometric Dating Does Work!Reports of the National Center for Science Education

Dence, M. R. 1976 The Manicouagan impact structure. NASA Spec. Pub.

Dence M. R. 1972: The nature and significance of terrestrial impact structures. 24th Inter. Geol. Congr. Section 15, 77–89.

Dietz, R.S. 1947, Meteorite impact suggested by the orientation of shatter cones at the Kentland, Indiana, disturbance, Science 105, 42-76.

Dressler, B.O. & Sharpton, V.L. 1997: Breccia formation at a complex impact crater: Slate Islands, Lake Superior, Ontario, Canada. TECTONOPHYSICS, 1997 Vol.275, No.4, pp. 285-311.

Dressler et al 1995, New Observations at the Slate Islands Impact Structure, Lake Superior NASA CR-205312

French, Bevan M. 1998. Traces of Catastrophe, A handbook of Shock-Metamorphic effects, Lunar and Planetary Institute.

French, B. M.,The importance of being cratered:The new role of meteorite impact as a normal geological process. Meteoritics & Planetary Science 39, Nr 2, 169–197. 2004.

French, Bevan M. 2005: STALKING THE WILY SHATTER CONE, Impact Field Studies Group, Vol.2. Winter 2005.

French, Bevan M. & Koeberl, Christian 2009; The convincing identification of terrestrial meteorite impact structures: Department of Paleobiology, Smithsonian Institution, Washington, DC, USA

Gibson, H.M. & Spray, J.G. 1998, Shock-induced melting and vaporization of shatter cone surfaces: Evidence from the Sudbury impact structure, Meteoritics and Planetary Sciences, 33, 329-336.

Grieve and Head, 1983. R.A.F. Grieve and J.W. Head, The Manicouagan impact structure: An analysis of its original dimensions and form.


Grieve, R.A.F. et al 2002. The recognition of terrestrial impact structures, Bulletin of the Czech Geological Survey, Vol. 77, No. 4, 253–263.

Grieve, R.A.F. 2006, Impact Structures in Canada (Geological Association of Canada).

Haskin, L et al 1998, The case for an Imbrium origin of the Apollo thorium-rich impact-melt breccias. Meteoritics & Planetary Science, vol. 33, no. 5, pp. 959-975.

Kenkmann, T. et al, 2009, Low angle collision with Earth: The elliptical impact crater Matt Wilson, Northern Territory, Australia, Geology; May 2009; v. 37; no. 5; p. 459-462.

Koeberl, C. & French, B.M. 2009; The convincing identification of terrestrial meteorite impact structures: Department of Paleobiology, Smithsonian Institution, Washington, DC , USA

Maddock, R.H., 1983. Melt origin of fault-generated Pseudotachylites demonstrated by textures, Geology, Vol 11, no 2.

McKean, F.K. 1964, A Meteoritic Crater in the Pre-Cambrian Shield, METEORITICS Vol. 2, No. 3.

Meen V.B. 1957, Merewether Crater – A Possible Meteor Crater, Proceedings of the Geological Association of Canada, 9, 49-67.

Melosh, H.J. 1980. Cratering Mechanics – Observational, Experimental, and Theoretical. the Annual Review of Earth and Planetary Sciences (book), 8, 626p.

Melosh, H. J., 1989. Impact cratering: A geologic process New York, Oxford University Press.

Melosh, H. J. and Ivanov, B. A. 1999, Impact Crater Collapse, Annu. Rev. Earth Planet. Sci. 1999. 27:385–415.

Murtaugh, J.G. 1972, Shock metamorphism in the Manicouagan cryptoexplosion structure, Quebec. Proc. 24th Int. Geol. Congr.

Nicolaysen, L. O., Reimold, W. U.; Vredefort shatter cones revisited – Journal of Geophysical Research: Solid Earth (1978–2012) Volume 104, Issue B3, pages 4911–4930, 10 March 1999.

Norton, O.R. 1998: ROCKS FROM SPACE, Mountain Press.


O’Dale, C.P. 2006; Manicouagan Impact Structure

Orphal, D & Schultz, P, An alternative model for the Manicouagan impact structure. Proc Lunar Planet Sci Conf 1978.

Osinski, G. 2008. Meteorite impact structures: the good and the bad: Geology Today, Vol. 24, No. 1, January–February 2008.

Gordon R. Osinski, and Ludovic Ferrière Shatter cones: (Mis)understood?, Science Advances 05 Aug 2016

Passchier, C. W., Trouw, R. A. J.; Microtectonics, Springer-Verlag, Berlin 1996. 289 pp.

Philpotts, A.R. 1964, Origin of Pseudotachylites, American Journal of Science, Vol 262.

Rayl, A.J.S. 2008; Hayabusa: Itokawa Beckons as Japan’s Spacecraft Searches for Places to Touch Down”.

Robertson P.B. 1968: La Malbaie Structure, Quebec – A Paleozoic Meteorite Impact Site: Meteoritics, Vol. 4 No. 2 October, 1968.

Rondot, J. 1966: Geology of the La Malbaie area, Department of Natural Resources, 544.

Rondot J. Geology of the La Malbaie region, Charlevoix. Quebec Preliminary Report 544. Quebec: Department of Natural Resources. 18 p. 1966.

Rondot, J., Impactite of the Charlevoix structure, Quebec, Canada. Journal of Geophysical Research, v. 76, pp. 5414-5423. 1971.

Rondot, J., Charlevoix and Sudbury as gravity-readjusted impact structures, Meteoritics & Planetary Science, v. 35, pp. 707-713. 2000.

Schmieder, M. 2010. Private correspondence.

Shoemaker, E.M. 1962, Astrogeologic Studies Semiannual Progress Report, Feb. to Aug., 1961, 74-78.

Shoemaker, E.M. 1963, The Moon, Meteorites and Comets, “The Solar System”, vol IV.

Simonds, C.H. et al 1976, Thermal model for impact breccia lithification: Manicouagan and the moon. Proc. Lunar Sci. Conf. 7th (1976) p. 2509-2528.

Spray J. 2010: METEORITE IMPACT CRATERS OF NORTH AMERICA, Observers Handbook 2010, Royal Astronomical Society of Canada.

Tancredi, G. et al 2009: A meteorite crater on Earth formed on September 15, 2007: The Carancas hypervelocity impact, Meteoritics & Planetary Science 44 No 12.

Wood C. A., Head J. W. 1976: Comparison of impact basins on Mercury, Mars and the Moon. Proc. 7th Lunar Sci. Conf., 3629–3651.

Wood, C.A. 2003. The Modern Moon, Sky Publishing Corp