Re: Large animal extinctions

Timo Niroma (
16 Jul 1996 12:45:54 GMT

In article <>, Dan Evens <> says:
>I think a meteor large enough to have caused any significant extinction would
>still have cratered the rock etc. under the ice. Anyway, I'd expect you could
>still go look for the remnants of the impact.
>In many ways, it does not matter whether it is an ocean impact or a polar ice cap
>impact. Meteors come in at 30 km/s or so, so they are in the ice for maybe 1/10th
>second or less. It really makes very little difference whether it is ice or liquid.
>The ice will use up a little more energy getting melted, but overall, that will
>make not much difference. (snips) Anything in the near distance (100's of km?
more?)gets flash cooked.
>Dan Evens

I agree that in some sense it does not make much difference.

If it would have hit the Greenland ice still there, there should be remnants left,
but such have not been found.

If it was in the Laurentidian ice sheet, not only the ice crater but all of the
surrounding ice has already melted.

If there is crater below the ice, it would still stand there. Any suggestions. At
least Canada is very well studied.