Holleford Crater

Holleford Crater is a meteorite crater near the community of Holleford, part of South Frontenac, Ontario, Canada. It is 2.35 kilometres (1.5 mi) in diameter and the age is estimated to be 550 ± 100 million years (Ediacaran or Cambrian). Although there is a surface depression over the area, the crater itself is not exposed at the surface.

Holleford Crater was discovered in the 1950s during analysis of aerial photographs under the direction of Dr. Carlyle S. Beals of the Dominion Observatory in Ottawa, Canada. In the late 1950s, the Geological Survey of Canada conducted a series of four geophysical studies: (1) magnetic observations; (2) seismic studies; (3) gravity studies; and (4) a diamond drilling program. The seismic and gravity studies and the drilling all produced data consistent with the impact theory. The drill core revealed breccia and similar materials at predicted depths. The studies concluded that an ancient meteorite impact crater is present in the Precambrian bedrock below the surface. The meteorite was estimated to be approximately 800 meters in diameter and to have impacted at approximately 55 thousand kilometers per hour.