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Fossil Shows Arctic Once Was Balmy



Another basically topical story, this one from A.P.  As always, posted
for fair-use discussion purposes only (ok, so the fair-use doctrine
isn't technically applicable, but it sounds cool).

Weishampel is interviewed.

Copyright 1998 Associated Press; acknowledged.

                     *  *  *

Fossil Shows Arctic Once Was Balmy

Filed at 4:46 p.m. EST


By The Associated Press
WASHINGTON (AP) -- The frigid Arctic regions were as balmy as present-
day Florida some 90 million years ago, according to researchers who
found fossils in northern Canada of a crocodile-like animal. 

At a place just 600 miles from the North Pole, researchers from the
University of Rochester found the fossilized remains of the
champosaur, a toothy, eight-foot-long extinct crocodile. 

``We found a whole assemblage of fossils, from both young and
adults,'' said geophysicist John H. Tarduno, the lead author of a
study appearing Friday in the journal Science. ``There were also
turtles and fish.'' 

The champosaur and the turtles are cold-blooded animals that could not
have survived in the current climate of the Canadian Arctic where the
fossils were found, Tarduno said. 

``These fossils tell us that there had to have been a substantial
growing season there then, and that the climate was very unlike the
Arctic now,'' he said. 

Temperatures at the fossil site now routinely drop to minus 60 degrees
Fahrenheit in the winter. But when the champosaur lived there 86
million to 92 million years ago, temperatures rarely reached freezing
and summertime readings of 80 degrees were common. 

``We think it was typical of what Florida is now,'' Tarduno said. 

No one had found a champosaur so close to the Arctic before, said
David B. Weishampel, a Johns Hopkins University dinosaur expert. 

``The new find suggests that the poles were a lot warmer and more
stable then than they are now,'' Weishampel said. 

The closest previous find of champosaur fossils was about 1,000 miles
south of the Canadian location, Tarduno said. 

The champosaur closely resembled the modern-day crocodile. It had a
long snout, powerful jaws filled with teeth and a long tail. 

Weishampel, the dinosaur expert, said the champosaur was probably cold
blooded, which means it had little tolerance for cold weather. It also
was too small to have migrated seasonally. 

Cold-blooded animals depend on the environment for warmth and become
immobile if the temperature is too cold. Warm-blooded animals can
regulate their body temperature even in cold weather. 

A field team from the University of Rochester found the fossils in a
layer of sediment sitting atop a 1,000 foot deep bed of lava rock. 

Tarduno said the Canadian lava flowed during a period of global
volcanism that saw immense basalt lava formations created near
Australia, in the Indian Ocean, near Madagascar, Brazil, and in South
Africa and the American southwest. 

The lava was different from the formations created by explosive
volcanoes. Instead, the melted rock flowed in great surges that
covered wide areas hundreds of feet deep and continued for hundreds of
years. 

Such a worldwide volcanic activity, said Tarduno, would have released
huge amounts of carbon dioxide, setting off a greenhouse effect that
would explain why the Arctic was warm enough for the champosaur. 

``It is very reasonable to suggest that so much CO2 was dumped into
the atmosphere that it overwhelmed the system, causing global
warming,'' he said. 

Tarduno said the warming period ``was a very narrow interval in
history, lasting only one to two million years. It was only a spike in
the Earth's climate pattern.'' 

Starting about 65 million years ago, around the time that the
dinosaurs were wiped out, the planet started a cooling trend, he said. 

As for the champosaur, it lived for several million years after the
dinosaurs disappeared. Then it, too, became extinct. 





==
Larry

"In our youths, our hearts were touched with fire."
--Oliver Wendell Holmes

http://members.tripod.com/~megalania/index.html

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