Schoch cited examples of vitrified rocks from around the world, plus he mentioned melting ice caps, etc., so it sounds like the plasma was scorching the entire planet, under his theory. It seems like a big space rock could have done nearly all the things that Schoch attributes to plasma.
If you're interested, Randall Carlson has a ton of YouTube videos focused on events around the end of the last ice age, but his view is that an asteroid or comet touched things off.
My answer was supposition. This whole thing opens a new line that I had not really “explored.” I think I have somne fun winter reading ahead of me.