"Extinction of the dinosaurs in North America"

Paul H bristolia at yahoo.com
Tue Mar 8 23:35:30 EST 2005

GSA TODAY Science Article:
The extinction of the dinosaurs in North America
http://www.eurekalert.org/pub_releases/2005-02/gsoa-mga022805.php

Fastovsky, D. E., and Sheehan, P. M., 2005, The
Extinction
of the Dinosaurs in North America. GSA Today. vol. 15,

no. 3, pp. 4-10. doi: 10.1130/1052-5173

http://www.gsajournals.org/gsaonline/?request=get-abstract&doi=10.1130%2F1052-5173(2005)15%3C4:TEOTDI%3E2.0.CO%3B2

http://www.gsajournals.org/gsaonline/?request=get-document&doi=10.1130%2F1052-5173(2005)15%3C4:TEOTDI%3E2.0.CO%3B2

"Did the dinosaurs really go abruptly extinct 65
million
years ago at the Cretaceous-Tertiary ("K-T") time
boundary, or was their K-T extinction the end result
of a gradual decline over millions of years? The
imperfect record available from scarce dinosaur
remains has made this question a true enigma
and the source of a long-standing and contentious
debate. David E. Fastovsky and Peter M. Sheehan
conclude, after a careful review of the fossil record
from the best-documented dinosaur sites (in
North America), that the extinction was indeed
geologically instantaneous. The authors argue
that the sudden die-off was different in scope
from previous fluctuations in dinosaur diversity
through the dinosaurs' 160 million years on Earth.
The authors consider the dinosaurs to have been
direct casualties of the K-T impact of an asteroid
with Earth and review several potential explanations
for the mechanism of the extinction. All of these are
concordant with the asteroid impact as the ultimate
cause."