MY AMATEUR IMPACT CRATER/STRUCTURE EXPLORATIONS
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 combined my hobbies of astronomy, geology and flying to explore impact craters and structures in North America from the air and ground. 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 find the geology in these craters and structures fascinating!
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).
CONFIRMED IMPACT CRATERS/STRUCTURES*
|Name||Diameter (km)||Age (million years)||Morphological type||Date Related Extinction||Notes|
|Barringer||1.19||0.049 ± 0.003||Simple1||Jointed|
|Holleford||2.35||550 ±100||Simple1||Overflight of Holleford Crater|
|West Hawk||2.44||100||Simple1||Geological dating|
|Viewfield||2.5||190 ± 20||Simple2||Triassic-Jurassic||Geological dating|
|Pingualuit||3.44||1.4 ± 0.1||Simple1||Overflight of Pingualuit Crater|
|Brent||3.8||396 ± 20||Simple1||Late Devonian||Overflight of Brent Crater|
|Ile Rouleau||4||<300||Central peak3||Geological dating|
|Wanapitei||3 to 7.5||37.2 ± 1.2||Flat floored?1|
|Gow||5||<250||Complex 2||Permian–Triassic (P–Tr) extinction event|
|Upheaval Dome||5.5||<170||Central peak4||Geological dating|
|Maple Creek||6||<75||Central peak5||Geological dating|
|Rock Elm||6||420–440||Central peak7||Ordovician|
|Pilot Lake||6||445 ± 2||Complex2||Ordovician|
|Elbow||8||395 ± 25||Complex2||Late Devonian||Geological dating|
|Lac La Moinerie||8||400 ± 50||Central peak1||Late Devonian|
|Lac Couture||8||425 ± 25||Central peak1|
|Red Wing||9.1||200 ± 25||Probable Complex8||Late Triassic/Triassic-Jurassic|
|Deep Bay||9.5||99 ± 4||Flat floored1||Geological dating|
|Eagle Butte||10||<65||Central peak2||Geological dating|
|Presqu'ile||24||<500||Central peak1||Geological dating|
|Clearwater East||26||290 ± 20||Central peak1||Possible Multiple Impact?|
|Mistastin||28||36.4 ± 4||Central peak basin6|
|Slate Islands||32||436 Ma ± 3||Central peak1||Ordovician|
|Clearwater West||32||290 ± 20||Peak ring1||Possible Multiple Impact?|
|Carswell||39||115 ± 10||Peak ring1|
|St. Martin||~40||219 ± 32||Central peak1||Late Triassic|
|Montagnais||45||50.5 ± 0.76||Central peak1|
|Charlevoix||54||342 ± 15||Peak ring1||Late Devonian||Elevated Earthquake Zone|
|Manicouagan||100||214 ± 1||Peak ring basin5||Late Triassic|
|Sudbury||250||1852 +4/-3||Multi ring?1||Sudbury Distal Ejecta|
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.
SUSPECTED IMPACT CRATERS/STRUCTURES
During my aerial meteorite crater explorations over various points of the North American Continent, I have noticed and documented a few geological features that are suspiciously shaped like meteorite craters. Also, I have investigated a few that were suggested by people who have contacted me after reading my meteorite articles. I have listed below the “crater like” structures that I have documented and could be confirmed as impact related if in the future evidence is found. I will be periodically adding more features as I visit them. If you have any additional information on any of the structures that I have documented or any new possible meteorite craters, please let me know.
|Non-Impact Circular Structures||Various|
|Lakes McGruther & Dell, Ontario||~2.3 Kilometres||Stratified circular feature|
|Fort Rae, Great Slave Lake, NWT||~2.8 Kilometres||Volcanic crater|
|Alsever Lake, Ontario||~4 Kilometres||Brent analog|
|Lake Skootamatta, Ontario||~5.5 Kilometres||Syenite/Pluton - Presqu'ile analog|
|Mount Moriah, Ontario||~5.5 Kilometres||Syenite/Pluton|
|Lake Mecatina, Quebec||~6.4 Kilometres||Stratified circular feature|
|Sainte-Véronique, Quebec||~9 Kilometres||Syenite/Pluton|
PLANET VS CRATER SIZE
|SOLAR SYSTEM BODY||DIAMETER km||GRAVITY||ESCAPE VELOSITY||BASINS km||PEAK RING km||COMPLEX km||SIMPLE km||REFERENCE|
|MERCURY||4,880||0.38||4.2 km/s||>~400||~110 - ~400||10 - 110||<~10||Greeley 2011|
|VENUS||12,104||0.91||10.4 km/s||-||>50 - 60||10 - ~50||<10 - 20||Greeley 2011|
|EARTH||12,756||1||11.2 km/s||>100||~30 - ~100||5 - ~30||<5||Grieve 2006|
|EARTH'S MOON||3,476||0.17||2.38 km/s||>220||175 - 220||30 - 175||<30||Wood 2003|
|MARS||6,788||0.38||5.0 km/s||~200||~20||~2.6||Greeley 2011|
Greeley, R. 2011, Planetary Geomorphology, Cambridge.
Grieve, R.A.F. 2006, Impact Structures in Canada, Geological Association of Canada.
Morrison, D. 2007 The Impact Hazard: Advanced NEO Surveys and Societal Responses, Comet/Asteroid Impacts and Human Society 2007, pp 163-173
Wood, C.A. 2003, The Modern Moon, Sky Publishing
RELATIVE SIZE OF CANADIAN METEORITE CRATERS/STRUCTURES
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.
Grieve R.A.F. & Robertson P.B. 1975, IMPACT STRUCTURES IN CANADA: THEIR RECOGNITION AND CHARACTERISTICS, Journal of the Royal Astronomical Society of Canada, February 1975.
CRATER EXPLORATION ACQUAINTANCES
Royal Society and published our Ottawa Centre RASC - Position Statement on Science and Evolution