[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]
> >... apparently, at least in North America, the forests
> >were temporarily removed, since immediately above the Iridium
> >layer almost all "pollen" is fern spores (for about a centimeter).
> >email@example.com firstname.lastname@example.org
> Interesting, since one prediction of the impact theory is regional
> forest fires. If they were severe enough, the surviving trees might
> a million years to re-seed themselves populously across the
Well, the 1 or so cm of fern spore domination represents, at most,
a few thousand years. Which is more or less the time it takes
to reestablish climax forest after clear-cutting (the time
varies from a few hundred to over a thousand years for this).
Also, I believe there is *not* a charcoal layer coordinate with
the Iridium spike in the Hell Creek, which suggests the reason
for the deforestation may *not* have been a fire.
[I have also seen one paper which claimed this deforestation
is not seen in most other parts of the world].
So, a while a fire is one possiblity, the shock wave itself
may also have been the cause.
> This is also predictable from the impact hypothesis. Global dust
would shut out
> the sunlight that planktonic forms need. This would disrupt the food
> the way to the large sea reptiles (plesiosaurs, et al). The
survivors on land
> and at sea would be the scroungers (small mammals and fish).
This is predictable on almost *any* extinction model.
It is not a differentiator. It is expected that forms with
wider tolerances (generalists) and with smaller resource
requirements wouls survive *any* sort of environmental stress
The peace of God be with you.