According to a recent theory, during an ice age, 12,900 years ago, a meteorite or comet struck the massive glaciers that covered the Great Lakes region. The catastrophe caused the extinction of the saber tooth tigers and other large animals that lived in North America at that time. Thus far, no meteorite fragments from such an impact have been found. The formation of the Carolina Bays has been claimed to be one consequence of the extraterrestrial impact. A meteorite strike on the Laurentide ice sheet would have sent enormous ice boulders from the glaciers, many as big as two football fields, all the way from central Michigan to the Carolinas and Georgia. The impacts of the huge chunks of ice formed shallow craters that became the Carolina Bays.
A new impact model solves the mystery of why almost all the Carolina Bays are perfect ellipses by interpreting them as conic sections. The oblique impacts created tilted conical cavities which at the intersection with the level surface of the Earth are conic sections that appear as elliptical craters. The ice boulders had velocities of 3 to 3.6 kilometers per second, which is much slower than the 17 kilometers per second for asteroids or 50 kilometers per second for comets. Impacts at the slower speeds would create shallow oval craters. The craters would be deeper at the terminal end due to the inclined incidence of the impact. The craters would also have raised rims, particularly at the terminal end of the ellipse. When the glacier ice impactors melted, the melt water created pools in the depressions. Most of the oval pools eventually filled by silting and viscous relaxation of the ground to produce the Carolina Bays.
Geologists have refused to accept Carolina Bays as impact sites because the target zones do not exhibit signs of shock metamorphism created by high velocity impacts and no meteorite fragments or chemical elements from meteorites have been found. The new impact model states that the slow speed of the glacier ice impacts would not produce shock metamorphism, and because the glacier ice is of terrestrial origin, there would be no traces of meteorites or sidereal chemical elements. However, the model predicts the location where it might be possible to find stones that were originally embedded in the glacier ice.