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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