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Re: _Night Comes to the Cretaceous_ Ad Infintium




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Message text written by INTERNET:dlessin@accesschicago.net

"Dinosaurs had already survived two MAJOR declines in their 200 million
year
history and  weathered both events with a multitude of new species. (again,
stresses on a population tend TO increase genetic variability)."


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        More than that, they (and virtually every other organism*)
apparently went unscathed through at least one major bolide impact, at the
Jurassic-Cretaceous boundary (craterin the subsurface of South Africa which
is estimated at being almost double the size of Chixulub)**.  So what was
peculiar about the K/T impact if it was the sole cause of the K/T
extinction?

*see:

Remane, J.  1991.  The Jurassic-Cretaceous boundary:  problems of
definition and procedure.  _Cretaceous Research_ 12:  447-453.

**see:

Corner, B., Reimold, W.U., Brandt, D. and Koeberl, C.  1997.  Morokweng
impact structure, Northwest Province, South Africa:  geophysical imaging
and shock petrographic studies.  _Earth and Planetary Science Letters_ 146:
 351-364.

and

Koeberl, C., Armstrong, R.A., and Reimold, W.U.  1997.  Morokweng, South
Africa:  a large impact structure of Jurassic-Cretaceous boundary age. 
_Geology_ 25(8):  731-734.

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                     Jerry D. Harris
                 Fossil Preparation Lab
          New Mexico Museum of Natural History
                   1801 Mountain Rd NW
               Albuquerque  NM  87104-1375
                 Phone:  (505) 899-2809
                  Fax:  (505) 841-2866
               102354.2222@compuserve.com