During the Younger Dryas, however, we had a resumption of a near polar freeze/thaw cycle for just under a thousand years. There are all sorts of strange ice shaped ground features in this region ~
Actually the Chesapeake crater, which is 34 million years old, ranges from Exmore on the DelMarVa Peninsula to Norfolk, about 50 miles in diameter. There is a 9 mile diameter crater off Atlantic City of the same age. Also the Popigai Crater in Siberia of the same age about 60 miles in diameter. The tectites I was referring to, which I may remember wrongly from 30 years ago, I thought were about 12 thousand years old.
The info on the Chesapeake event leads me to the thought that there may have been more than one boloid strike at the start of the Younger Dryas. This could explain certain anomolies.
If you have not yet read the book Chesapeake Invader by C. Wylie Poag, you might want to check it out.