Of course this is it. If you think you can explain this away with some crackpot theory of ice sheet melting and glacial lake discharge, be my guest. I'll listen.

I deduced that it had to be in this area on the discharge and runoff proxies ALONE, totally ignoring the Carolina bays, extinctions and the rest of it, and I even tested the fidelity of the Google terrain maps for an hour or two before I started, on glacial features in southern Wisconsin which I am intimately familiar with. I assumed that if it didn't hit directly on the great lakes, then the impact certainly was large enough that I would be able to identify it in the terrain maps, and I was shocked, SHOCKED I tell you, when I found this thing in a few minutes.

The only reason I looked for this at all is that there were no indications at all anywhere in the literature that ANYONE even bothered to take the time to look.

The impact simulator indicates it arrived at the surface of the ice sheet 90% intact. The extinctions are easily explained by the triple whammy of predation, impact and rapid climate change. If it came in from the southeast, it would have easily shed enough material to explain the Carolina bays. If it came in from the northwest, it would have thrown debris indistinguishable from glacial erratics all over the great lakes. If there were multiple impacts, the comet or outer moon impact ice fragments would have had been prefragmented either by impact or gravitationally, because clearly something this large will impact nearly intact.

This is your baby, trust me, or refute me. I reserve the right to be totally wrong.