From OttawaRasc
Jump to: navigation, search


by: Charles O'Dale
Unless otherwise indicated, all of the aerial images on this RASC 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.
This is me fulfilling one of my lifelong dreams, exploring impact craters (but only on this planet at the present time!!).
EXTINCTIONS VS Possible Impact RelationshipIcon-new.gif
My crater articles in AstroNotes
Exploring the Pingualuit Impact Crater April 2009, JRASC
RASC - The Planetary Society


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

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!

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

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.

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


*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.
Name Diameter (km) Age (million years) Morphological type Date Related Extinction Notes
Whitecourt 0.036 0.00113 Simple1
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 Icon-new.gifNov. 2014
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 Ordovician
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 ~460–470 Icon-new.gif2014 Central peak1 Ordovician 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 Icon-Updated.gifOct. 2014 Peak ring1 Possible Multiple Impact?
Carswell 39 115 ± 10 Peak ring1
St. Martin ~40 227.8 ±0.9 Icon-new.gif2014 Central peak1 Late Triassic
Montagnais 45 50.5 ± 0.76 Central peak1
Charlevoix 54 342 ± 15 Peak ring1 Late Devonian Elevated Earthquake Zone
Beaverhead ~100 ~600 Peak ring1
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.


Name Diameter (km) Age Suspect Morphological type Date Related Extinction Notes
Merewether, LabradorIcon-Updated.gifOct. 2014 0.19812 (largest of three) <870 years ? Simple Younger Drias extinction?
Bloody Creek, Nova Scotia 0.350 X 0.420 ~12,000 years? Simple Younger Drias extinction?
Charity Shoal, Lake Ontario ~1  ? Simple Younger Drias extinction?
Florida Crater/StructureIcon-new.gifMarch 2015 ~1 <40 ma - Estimate Central Peak?
Eclipse Lake, Labrador 1.5  ? Simple - Possible flat-floored Younger Drias extinction?
Lac de Courval, Quebec ~1.6  ? Simple Circular lake
Franktown structure, Ontario ~2 >400 ma Simple Circular depression
Lac du Bonnet, Manitoba ~3.8  ? Simple Circular magnetic anomaly
Corossol Structure, Gulf of St. Lawrence 4.0 ~12,000 years? Central Peak Younger Drias extinction?
Charron Lake, Ontario >4.5  ? Simple Negative magnetic anomaly
Kakiattukallak Lake, Quebec 3 - 6  ? Simple Possible Multiple Impact?
Skeleton Lake, Ontario 3.5 ~800 ma Simple Geological dating
Panther Mountain, New York state 10 ~375 ma Central peak Late Devonian Inverted relief
Can-Am, Lake Huron 100 ~500 ma Central peak Underwater in Lake Huron
Touchwood Hills, SaskatchewanIcon-new.gif >200 >541 ma Multi-ring Basin? Under the Williston Basin
Hudson Bay Arc >450  ? Multi ring basin? AKA - Nastapoka Arc


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.

Name Diameter Morphology
Non-Impact Circular StructuresIcon-Updated.gif 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


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
The depth to diameter ratio of craters smaller than a certain size is a constant, as predicted by the Maxwell Z-model. Below a break point (10 km for the Moon), the ratio follows a power law, decreasing as size increases [Hiesinger, 2006, Sharpton, 1994]. Source: [Hiesinger, 2006].
The primary factors governing the size and shape of impact craters are the impact energy, gravity and properties of the target. Gravity affects the cratering process by influencing the dimensions of the excavation bowl, the extent of the ejecta and various post-impact crater modifications. In the modification stages of impact cratering, gravity influences the degree of slumping, perhaps governing the size of potential central uplifts (Greeley 2011).
The Earth is immersed in a swarm of Near Earth Asteroids (NEAs) capable of colliding with our planet, a fact that has become widely recognized within the past decade. The first comprehensive modern analysis of the impact hazard resulted from a NASA study requested by the United States Congress. This Spaceguard Survey Report (Morrison 1992) provided a quantitative estimate of the impact hazard as a function of impactor size (or energy) and advocated a strategy to deal with such a threat (Morrison, 2007).


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


Odale-Relative sizes sm.jpg


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.


Dr. Michael R. Dence and yours truly at a 2012 Sigma Xi Companions in Research meeting, Ottawa. Dr. Dence was prime on impact crater research within the Canadian Shield, 1961-81. He was one of the few indiviuals responsible for transforming terrestrial impact crater research into a respectable and scientific discipline of planetary science.
Dr. Ian Halliday and yours truly, Ottawa 2012. Dr. Halliday was a pioneer on impact crater research authoring several papers on the subject. His field research provided evidence in support of a meteoritic origin for West Hawk Lake, Manitoba, Canada
Dr. Christopher Herd and yours truly at the 2012 RASC GA in Edmonton. Dr. Herd is Associate Professor, Department of Earth and Atmospheric Sciences at the University of Alberta. He was prime in the confirmation of the Whitecourt Crater as an impact structure.

Yours truly with Blyth Robertson. We are standing in front of a desiccation structure (fosilized creek). Dr. Blyth Robertson is Emeritus Scientist with the Geological Survey of Canada. Of the 37 years that he spent with Natural Resources Canada, Dr. Robertson spent 20 years researching impact craters in Canada and worldwide. In the 1970's Dr. Robertson was instrumental in confirming the impact nature of a large site in northern Canada known as the Haughton Crater.

"Civilization exists by geological consent .... subject to change without notice." - W. Durant

Odale-Disclaimer message.gif

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.
As a member of the Ottawa Centre of the Royal Astronomical Society of Canada, I am proud that we joined with the Royal Society and many other Scientific and Scholarly Organizations to publish our Ottawa Centre RASC - Position Statement on Science and Evolution

"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

Back to the main OTTAWA CENTRE RASC page.

Personal tools