As the freeze/thaw cycle does its work, some rocks rise, and other rocks fall through the soil. The net result is a circle of rocks of relatively similar size.
It's a least energy cost pathway sort of mathematical form.
No doubt one of the effects of the comet was to encourage the continuation of the glacial period for another thousand years, and that would have given us more circles ~ many of them quite large.
I've heard that the Carolinas got pretty cold in the Younger Dyrass. My own frontyard got pretty cold then, and even before that time. You can go back something like 600 million years to the "snowball earth" thing, and find out that recurring glaciation at the latitude where Virginia was located at that time probably created the 100,000,000 trillion glacial rocks located in the disaggregated schist just below the surface of the clay.
I even have a recurring salt spring on this lot!
Why are the circles elliptical and oriented in a direction? At Prudhoe Bay there are similar looking features shaped by prevailing wind.
I'm familiar with that action...however, it does not produce iridium or diamonds.
"In samples taken from 15 of the features, Howard and his colleagues found iridium-rich magnetic grains and carbon spherules with tiny diamond fragments similar to those found at Clovis archaeological sites."
Freeze Thaw cycles typically produce forms that are hexagonal in shape, not elliptical. I can’t say what these elliptical shapes are, but they do not look like anything formed by freeze thaw.
I had some disaggregated schist last week, but a little Pepto-Bismol cleared it right up.