FRANKTOWN “Circular Structure”

by: Charles O’Dale

  • Type: Simple
  • Location: N 45° 00.3’ W 76° 03.2’
  • Diameter: ~2 Km
  • Age Ma: >400aDEVONIAN

a minimum age based on Ordovician sediment cover

The Google Earth image of the Franktown structure reveals a circular formation.
The Franktown structure from 1200′ AGL, a circular geologic formation can be seen.

An article by Beals et al in the 1964 Journal of the RASC article (below) proposed that this Franktown Ontario structure may be the result of a cosmic impact. This report was published before any geological studies were performed at the site in order to find impact features.

A later article by Freeberg in the 1966 Geological Survey Bulletin stated that drilling investigation did not reveal any impact related geology. I have not found any reports describing the drilling performed at this site.


On the base of the north rim looking “up” the crater wall.
On the top of the south rim looking “into” the structure.

In conclusion, a remote possibility exists that this structure is impact related.



Beals, C.S., Innes, M.J.S., and Rottenberg, J.A., 1960, The search for fossil meteorite craters-II: Current Science, n.6, p.250-261.

Beals, C. S., Ferguson, G. M., & Landau, A., [Scientists Report II.] A Search for Analogies Between Lunar and Terrestrial Topography on Photographs of the Canadian Shield, Part II,Journal of the Royal Astronomical Society of Canada, Vol. 50, p.257-258

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

Freeberg, J.H., Terrestrial Impact Structures – a Bibliography. Geological Survey Bulletin 1220, 1966.