Wow.... interesting.
Try "wow, how insane!"
Try applying Occam's razor. What happened 13,000 years ago? The current "native-americans" who came from Mongolia arrived, and quickly hunted all the big game to extinction.
The same extinctions happened, at a different time, in Madagascar, when Asians arrived. So are we to believe, i.e., that two DIFFERENT supernovas can explain that extinction cycle?
Rubbish!!