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!
While studying the physics of impact sites, I have found that circular geological features can be produced by a number of geological processes, including 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). You can see below some of the non-impact structures that I have explored over the past few years.
Stewart S. A. 2003. How will we recognize buried impact craters in terrestrial sedimentary basins? Geology 31:929–932.
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, Arizona||1.19||0.049 ± 0.003||Simple1||Jointed|
|Beaverhead, Montana/Idaho||~100||~600||Peak ring1|
|Brent, Ontario||3.8||396 ± 20||Simple1||Late Devonian||Overflight of Brent Crater|
|Carswell, Alberta||39||115 ± 10||Peak ring1|
|Charlevoix, Quebec||54||342 ± 15||Peak ring1||Late Devonian||Elevated Earthquake Zone|
|Clearwater East, Quebec||26||~460–470||Central peak1||Ordovician||Possible Multiple Impact?|
|Clearwater West, Quebec||32||290 ± 20||Peak ring1||Possible Multiple Impact?|
|Cloud Creek, Wyoming||7||~190 +/- 30 Ma||Complex2||Triassic-Jurassic||Dated chronostratigraphicly|
|Deep Bay, Saskatchewan||9.5||99 ± 4||Flat floored1||Geological dating|
|Des Plaines, Illinois||8||<280||Complex2||Geological dating|
|Eagle Butte, Alberta||10||<65||Central peak2||Geological dating|
|Elbow, Alberta||8||395 ± 25||Complex2||Late Devonian||Geological dating|
|Glover Bluff, Wisconsin||8||<500||Complex2||Geological dating|
|Gow, Saskatchewan||5||<250||Complex 2||Permian–Triassic (P–Tr) extinction event|
|Holleford, Ontario||2.35||550 ±100||Simple1||Overflight of Holleford Crater|
|Ile Rouleau, Quebec||4||<300||Central peak3||Geological dating|
|Lac Couture, Quebec||8||425 ± 25||Central peak1||Ordovician|
|Lac La Moinerie, Quebec||8||400 ± 50||Central peak1||Late Devonian|
|Manicouagan, Quebec||100||214 ± 1||Peak ring basin5||Late Triassic|
|Manson, Iowa||~35||73.8||Central peak1|
|Maple Creek, Saskatchewan||6||<75||Central peak5||Geological dating|
|Mistastin, Labrador||28||36.6 ± 2||Central peak basin6|
|Montagnais, off Nova Scotia||45||50.5 ± 0.76||Central peak1|
|Newporte, North Dakota||3.2||<500||Simple2||Geological biostratigraphic dating|
|Pilot Lake, North West Territories||6||445 ± 2||Complex2||Ordovician|
|Pingualuit, Quebec||3.44||1.4 ± 0.1||Simple1||Overflight of Pingualuit Crater|
|Presqu'ile, Quebec||24||<500||Central peak1||Geological dating|
|Red Wing, North Dakota||9.1||200 ± 25||Probable Complex8||Late Triassic/Triassic-Jurassic|
|Rock Elm, Wisconsin||6||420–440||Central peak7||Ordovician|
|Slate Islands, Lake Superior||32||436 Ma ± 3||Central peak1||Ordovician|
|St. Martin, Manitoba||~40||227.8 ±0.9||Central peak1||Late Triassic|
|Sudbury, Ontario||250||1852 +4/-3||Multi ring?1||Sudbury Distal Ejecta|
|Upheaval Dome, Utah||5.5||<170||Central peak4||Geological dating|
|Viewfield, Saskatchewan||2.5||190 ± 20||Simple2||Triassic-Jurassic||Geological dating|
|Wanapitei, Ontario||3 to 7.5||37.2 ± 1.2||Flat floored?1|
|West Hawk, Manitoba||2.44||100||Simple1||Geological dating|
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
|Name||Diameter (km)||Age||Suspect Morphological type||Date Related Extinction||Notes|
|Bloody Creek, Nova Scotia||0.350 X 0.420||~12,000 years?||Simple||Younger Drias extinction?|
|Bow City, Alberta||6||<75||Central peak5||Geological dating|
|Can-Am, Lake Huron||100||~500 ma||Central peak||Underwater in Lake Huron|
|Charity Shoal, Lake Ontario||~1||?||Simple||Younger Drias extinction?|
|Charron Lake, Manitoba||>4.5||?||Simple||Negative magnetic anomaly|
|Corossol Structure, Gulf of St. Lawrence||4.0||~12,000 years?||Central Peak||Younger Drias extinction?|
|Dumas, Saskatchewan||4||<70||Simple1||Late Cretaceous||Geological dating|
|Eclipse Lake, Labrador||1.5||?||Simple - Possible flat-floored||Younger Drias extinction?|
|Florida Crater/Structure||~1||<40 ma - Estimate||Central Peak?|
|Franktown structure, Ontario||~2||>400 ma||Simple||Circular depression|
|Hartney, Manitoba||6||<190 ± 20||Complex? 2||Triassic-Jurassic||Geological dating|
|High Rock Lake, Manitoba||~5||435 ± 10||Complex2||Ordovician||Geological dating|
|Howell Creek, BC||10||90-97 ma||Simple||Circular geologic formation|
|Hudson Bay Arc||>450||?||Multi ring basin?||AKA - Nastapoka Arc|
|James River, Alberta||4.8||<480||Complex2||Ordovician||Geological dating|
|Kakiattukallak Lake, Quebec||3 - 6||?||Simple||Possible Multiple Impact?|
|Lac de Courval, Quebec||~1.6||?||Simple||Circular lake|
|Lac du Bonnet, Manitoba||~3.8||?||Simple||Circular magnetic anomaly|
|Merewether, Labrador||0.19812 (largest of three)||<870 years ?||Simple||Younger Drias extinction?|
|Panther Mountain, New York state||10||~375 ma||Central peak||Late Devonian||Inverted relief|
|Purple Springs, Alberta||6||<75||Central peak5||Geological dating|
|Skeleton Lake, Ontario||3.5||~800 ma||Simple||Geological dating|
|Touchwood Hills, Saskatchewan||>200||>541 ma||Multi-ring Basin?||Under the Williston Basin|
|Victoria Island, California||5.5||37-49 ma||Simple||Geological dating|
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|
|Manitou Islands, Ontarilo||4 Kilometres||Carbonatite Volcanoe 577 Ma|
|Callander, Ontario||4 Kilometres||Carbonatite Volcanoe 577 Ma|
|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|
|Croker Island Complex, Ontario||~10 Kilometres||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 many other Scientific and Scholarly Organizations to publish our Ottawa Centre RASC - Position Statement on Science and Evolution