The ORIGINAL ARTICLE(w/Topping) made several references to the liklihood(?) of a hit from a supernova. Conspicuously missing from the article cited for this thread along with another theory; that is, carbon dates, particularly associated with paleoindian dates, were quite possibly much too young -- by about 40,000 - 50,000 years. I gather that theory has been abandoned. Which MAY be why Topping is back in the references and cites in the article on THIS thread?
I was never very comfortable with that idea. I think they are on a better track with this current article. And, they seem to have some pretty good evidence.
There was a split; Bill Topping (I think that’s his name) first turned in the direction of an ET cause, but at some point (perhaps as the “new guy” added members to the team) parted company. :’) Not sure what you mean about 40K-50K too young for RC dates — the RC limit is around 50K, beyond which the level of 14C is too low. However, there were some 14C “spikes” which caused older stuff to appear younger, as the ratio was thrown off. That is discussed in the book. Other radiometric stuff is discussed as well. The earlier waves of bombardments are discussed quickly, but I suspect those will someday be fleshed out.