There is a Russian scientist or author, I believe his name is Kolisimov, who has speculated that the sudden freezing of Siberia was caused by an abrubt tilt of the earth on it's axis due to impact by a celestial body (comet, etc.). I don't recall the impact date he cited.
That is worth a thread sometime in the future.
Yeah, that could be. I think there are 2 things that could trigger it. A meteor strike or a pole switch. The sun switches poles every few years. If the earth's core is like the suns core, maybe it flips every few thousand years. Or maybe there's another body we're not aware of that is highly electromagnetic that's on a long very elliptical orbit. It would explain the asteroid belt, Uranus on it's side, Pluto on it's wild orbit, and maybe even our moon. Our earth is like a big magnet, if another powerful magnet were introduced and got relatively close to the earth, the earth's core would try to align with it.
It's got to be something. The mammoths are frozen standing up with tropical plants in their mouths. Something caused it.