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Re: Cretaceous Mass Extinction
> email@example.com wrote:
> Why didn't they adapt that last time? Adaptive radiation doesn't
> answer my 0uestion entirely.
> Sorry I am a little late on this, but as the "mad photoperiod-extinction
> theorist" I felt compelled to comment on this entry (which was quite
> interesting, by the way!).<major snip>
> Catastrophic photoperiodic change is the
The latest supercomputer modeling (personal commumication) when
looked at conservatively and avoiding the extremes at both ends,
shows the atmosphere being cleared of most of the smoke and dust
relatively quickly (read days to few weeks). Now this is models, and
not hard data, so take it with a grain of salt. The extremes do
call for long term nuclear winter.
Assuming the mid range predictions are close to correct, then there
is no room for nuclear(bolide) winter or problems with photoperiods.
Nor is there long term problems with acid rain. Remember, this was a
singular event. Even with worldwide forest fires, the atmosphere
could rapidly clear it. It is not the same as a massive series of
volcanic eruptions constantly pouring dust and ash into the air.
I have thought that dinosaurs were on the out prior to the collision
and that it didn't help. I now wonder about two things since the
collision was so violent(read massive bolide).
The first is the local affect to the North American Continent. The
energy from the blast likely devastated the continent. Only those
animals protected from the initial blast and heat would have
survived. Likely some did.
Next would have been reentry phenomena. It would have been
worldwide. The heat from the local blast, reentry of plasma, rock
and comet, then resultant forest fires would have raised worldwide
temperatures within hours to lethal levels. I think this is what
killed the majority of animals, and would explain why only those that
could get into or were in protected environments could survive or
did. Did all the large land based animals die right away?.
Statistically unlikely but possible. Did it knock them down and they
never got back up? I think so. Certainly there were long term
aftermath problems for most of earth's organisms.
I wonder what sea temperatures would have risen to and what affect it
would have? Where do the sea based animals especially large ones fit
into this? Did sea temps rise enough to kill them? Seems unlikely
but I haven's seen those numbers crunched. Acid rain disrupt the
food chain? Or did air temperatures get hot enough for say 30-60
minutes to a few hours to kill them?
Feel free to blast holes in this because it's not my theory.
Bad day in Blackrock.