[meteorite-list] North Slope Dinosaurs May Crush Asteroid Theory

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Apr 22 09:54:10 2004
Message-ID: <200202252001.MAA02580_at_zagami.jpl.nasa.gov>

http://adn.com/opinion/story/770393p-822177c.html

North Slope dinosaurs may crush asteroid theory
By Ned Rozell
Anchorage Daily News
February 24, 2002

A colossal meteorite that slammed into Earth about 65 million years ago may
have killed the dinosaurs, but there's a good chance it did not. The proof
may be locked in the permafrost of Alaska's North Slope.

A 60-mile stretch of the Colville River holds layers of well-preserved
dinosaur bones that researchers can't reach using conventional methods.
Roland Gangloff and his colleagues hope to get funding soon to mine the
permafrost for fossils and possibly unearth one of the greatest riddles of
history -- what killed the dinosaurs?

Gangloff is earth science curator of the University of Alaska Museum in
Fairbanks and an associate professor of geology and geophysics. He teamed
with Australian colleagues Thomas Rich and Patricia Vickers-Rich to write a
paper on polar dinosaurs published in the Feb. 8, 2002 issue of the journal
Science.

The far-north and far-south dinosaur hunters suggest that polar dinosaurs
were some of the most adaptable creatures to ever live, perhaps too
resilient to be killed by the affects of one giant
asteroid. The prevailing theory on the demise of the dinosaurs is that a
meteorite struck Earth about 65 million years ago, kicking up dust that
blocked the sun's rays and chilled the planet to
temperatures intolerable for dinosaurs.

"If dinosaurs adapted to such a variety of environments, how did one nuclear
winter knock them off?" Gangloff said. "Anyone who explains the whole
picture of dinosaur extinction has to explain high-latitude dinosaurs."

Arctic dinosaurs first made the news in the early 1960s, when geologists and
paleontologists found dinosaur footprints embedded in rock on the island of
Spitzbergen and found dinosaur bones falling from the banks of the Colville
River in Alaska. Since then, researchers have found scattered evidence of
the creatures from the high Arctic of Canada to near the South Pole.

The Colville River remains the richest deposit in Alaska. According to plant
fossils dating to the period from 85 to 100 million years ago -- a time
consistent with the fossilized dinosaur tracks -- Alaska had a climate
similar to the southern California coast. Alaska's climate was more like the
coasts of Oregon and Washington 68 to 85 million years ago, the period to
which paleontologists have dated most of the bones found near the Colville
River.

The Australian researchers found dinosaur bones alongside prehistoric
evidence of permafrost in southeastern Australia. Using oxygen-isotope
methods to determine the average temperatures at the
time the far-south dinosaurs lived, the scientists came up with a reading of
about minus 2 degrees Celsius. The modern mean annual temperature of
Fairbanks is minus 2.9 degrees Celsius.

Alaska and Australia paleontologists have both discovered species of
dinosaur with bulging eyes and brains, which may have been an adaptation to
low light.

Dinosaurs that lived far from the warmth of the equator -- possibly in
climates as extreme as present-day Fairbanks -- may make people rethink how
dinosaurs lived and died. Hundreds of clues wait beneath the floodplain of
the Colville River, frozen where dinosaurs died en masse millions of years
ago.

Ned Rozell is a science writer at the Geophysical Institute, University of
Alaska Fairbanks. He can be reached by e-mail at nrozell_at_dino.gi.alaska.edu.
A glossary of Alaska Science Forum
columns is available online: www.gi.alaska.edu/ScienceForum/wildlife.html
Received on Mon 25 Feb 2002 03:01:05 PM PST