The problem remains the foundation of the claim, which is, an impact happens, and has no effect on anything, it’s just a huge coincidence. Now that the rapidity of the complete killing of whole taxa can no longer be denied (it was for 20+ years), well, gosh, maybe the impact caused these volcanoes to go off...
No, those large impacts are enough by themselves.
I’d also point out that volcanic activity has local effects, but there is no worldwide trace of massive volcanic activity in the paleontological boundary layers. None. Anywhere. There was of course an attempt to attribute the iridium to volcanic activity, but that was shown to be (and previously known to be) nonsense. The Earth doesn’t have enough iridium in its depths to produce a spike like that.
I was thinking that an asteroid hit could cause the huge lava flows like the Deccan or Columbia on the opposite side of the globe from impact.
I know when I was a kid and the IGY provided traction for the plate tectonics theory that it had taken a couple of generations from Wegener to be accepted. Had to get the old professors and their students out of the way I reckon.
The Alvarez guys had quite a battle too, didn’t they?
BTW, I have the Pierce translation of The Oera Linda Book and it puts the sinking of Aldland at 2193 BC.