Expert: Courtney Seligman - 4/23/2009

Question
dear Courtney Seligman,


Thank you very much for the answer you gave me yesterday.


During Earth's past; more PRECISELY just before the formation of the first mountains-ranges (ie, 1 or 2 billions years ago),

is it true that the whole Earth's surface used to continually drift so violently/quickly (due to different geological factors and forces were shaping the planet) that, if humans had been there, that movement would have been felt by them and would have made them kill?

And that collisional mountains-ranges 'control' that very violent drifting (which have gave birth to them) and make it very mild, in order that animal and humans can live?




sincerely

Answer
It is highly unlikely that general surface motions such as continental drift have ever exceeded a few feet per year. In any event, 'violent' events (such as portrayed in fantasies such as "One Million BC") would not have been any more common in periods as short as a human lifetime even as far back as 3 or 4 billion years ago. So, presuming humans had evolved by then, they shouldn't have had any trouble living ordinary, everyday lives.

But even if motions had been faster, as long as they were more or less uniform, those living on the surface wouldn't have been affected. All they would notice is sudden stops, which is what mountain-building events (collisions between tectonic plates) represent. So when mountains are being built up, life would be more difficult and dangerous than when the continents are merely drifting.

This doesn't mean that there haven't been some spectacular earthquakes and volcanic events in past times, which have not occurred recently. But that isn't because those events can't occur any more. It's because they occur only very rarely, and our lives are too short for any of them to have occurred while we were around to notice. There will certainly be violent events in the future; just (most likely) so far in the future, that humans will probably be extinct long before then.