Impact senerios

[dis@gj.net]

All.

Just a few things to keep in mind. I had the good fortune to be a part 
of the Univ. of Colorado extinction group under Dr. Erle Kauffman. We 
approached Cret mass-extinctions mainly from the marine end. We covered 
both the Cenomanian/Turonian (mid-Cretaceous event- step wise extinct 
with iridium right at two of the steps) and the K/T extinctions. I have 
had the good fortune to sample several sites terrestrial and marine with 
Walter Alvarez and was part of the group that first identified the tidal 
wave on the Gulf Coast. 

Here are a few thoughts.

 We still do not understand the mechanisms of impact induced 
extinctions.

I mean some scientists have speculated on acid rain levels high enough
 to drive ocean ph to 4-5. This would have killed everything. Pretty
 stupid suggestion.

         My researches in the Cretaceous marine strata of NA (with many
 others) have documented many volcanic explosions that covered all of NA
 in feet of ash with no extinctions at the species level.

         Impacts are obviously fundamentally different. But how? Putting
 materials into orbit, interfering with reproduction, disrupting food
chains or what?
 
 
The scale of the K/T impact is tremendous. It says something 
fundamental.

Life is tough.
 
 The impact happened (FACT) and life survived (FACT).
 
 I tend to think that with all the vaporized Carbonate CO2 probable
 helped counteract the dust. Super greenhousing.
 
 Jim Kirkland
Dinamation Int'l Soc.