Re: [Re: K-T question]

[Stanley Friesen <sarima@friesen.net>]

At 01:06 PM 6/2/00 -0600, Caleb wrote:
>    Well, what I want to know is the paleopopulation with the plantlife as
> immediately before and after (and during) the K-T boundary. Could you also
> explain the warming-cooling trends in the plant life too, and when exactly
> they occur?
There is some indication that this may be regionally specific.

In the Lance and Hell Creek there appears to be a narrow zone of 
depauperate flora immediately above the Iridium spike.  This shows up 
mostly in pollen and spores, which become dominated by fern spores for a 
few centimeters above the boundary.

Further up the flora is decidedly cooler and wetter in aspect than that of 
the Latest Cretaceous.  But that is to be expected, as world temperature 
reached a major low point during the earliest Paleocene.  One correlate of 
this is that the formations overlying the Lance and Hell Creek have much 
more coal (lignite) than the earlier formations.  Lithologically, the Lance 
and Hell Creek Formations end at the first regionally persistent coal 
bed.  This is usually several meter above the Iridium layer.

However, there are strong indications that these results do NOT apply 
elsewhere in the world.  In several sequences there is little detectable 
change in the flora across the boundary.


[Note, given the location and direction of the impact, central North 
America would have been particularly hard hit by the shock-wave and "fallout"].

--------------
May the peace of God be with you.         sarima@ix.netcom.com