by: Charles O’Dale

*In my articles I use the term crater to define a circular impact depression and the termstructure to define an impact crater that is severely altered by erosion.

  • Proposed: some structural, geological and/or geophysical evidence
    exists but the impact origin is still highly uncertain for the lack of data.
Name Diameter (km) Age (million years) Dating method Morphological type Notes
Carolina Bays, NC Various ~0.0129-0.14 Not firmly quantified  Simple Younger Drias black mat
Charity Shoal, Lake Ontario ~1  ? Simple underwater Lake Ontario Negative magnetic anomaly
Charron Lake, Manitoba >4.5  ?  Simple Negative magnetic anomaly
Corossol Structure, Gulf of St. Lawrence 4.0 ~0.012 14C age shells in sediments Complex Underwater Gulf St. Lawrence
Douglas, Wyoming ~0.08 ~280 Sedimentological boundary  Simple Multiple Strewn Field
Franktown Structure, Ontario ~2 >400 Ordovician sediment cover  Simple Circular depression
Hotchkiss Structure, Ontario 3.9 120-330 Dated unconformity Complex Seismic research
Kakiattukallak Lake, Quebec 3 – 6  ?  Simple Possible Multiple Impact?
Lac de Courval, Quebec ~1.6  ?  Simple Circular lake
Lac du Bonnet, Manitoba ~3.8  75 Sedimentary cover depth  Simple Circular magnetic anomaly
Upheaval Dome, Utah 2.57 <170 Geological dating Complex4 Younger than the Jurassic Navajo Sandstone
Victoria Island, California 5.5 37-49 Drilling data  Simple Geological dating


“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