[meteorite-list] Cosmic Impacts Implicated In Both The Rise And Fall Of Dinosaurs

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Apr 22 10:04:49 2004
Message-ID: <200205162104.OAA01402_at_zagami.jpl.nasa.gov>

http://uc.rutgers.edu/medrel/viewArticle.phtml?ArticleID=2396

Media Relations
Rutgers

Contact:
Bill Haduch, 732/932-7084, extension 633
E-mail: bhaduch_at_ur.rutgers.edu

May 16, 2002

Cosmic impacts implicated in both the rise and fall of dinosaurs

NEW BRUNSWICK/PISCATAWAY, N.J. -- New abilities to detect layers of
"space dust" in the earth's crust are building geological evidence
that comets or asteroids colliding with earth not only helped wipe
out the dinosaurs, but may have originally helped bring them to
prominence about 200 million years ago.

Dennis V. Kent, Rutgers geology professor, was among a team of
geologists who analyzed footprints, bones and plant spores in more
than 70 locations in eastern North America, as well as iridium dust
and magnetic fields in four corresponding sediment layers in the
Newark Basin. The team published its findings, "Ascent of Dinosaurs
Linked to an Iridium Anomaly at the Triassic-Jurassic Boundary," in
the May 17 edition of the journal Science.

"Finding the element iridium, which is common in space objects,
creates a time marker for comet or asteroid impacts." said Kent.
"Correlating the finds with evidence of plant and animal life helps
to tell us what happened."

Using high-resolution spectrometry technology provided by Christian
Koeberl of the University of Vienna in Austria, the scientists were
able to make unprecedented comparisons of iridium levels in the
parts-per-trillion range. Kent said another important find was a
thin zone in the sediment, just below the Triassic-Jurassic boundary,
where the magnetic field is reversed. This reverse zone can now serve
as a marker to help identify the boundary location in the geological
record.

"Our research adds to the speculation that there was a comet or
asteroid impact about 200 million years ago, followed relatively
quickly by the rising dominance of dinosaur populations of the
Jurassic period," said Kent. He suggested that the effects of the
impact killed off or reduced many competitive species, clearing the
way for dinosaurs to adapt and flourish.

"Dinosaurs went on to dominate for the next 135 million years," he
said, noting that their extinction is now commonly attributed to
the ecological effects of yet another comet or asteroid impact --
this one about 65 million years ago.

Besides his work at Rutgers, Kent is associated with the Lamont-
Doherty Earth Observatory of Columbia University, as are his
co-authors E.C. Rainforth and P.E. Olsen. Olsen's earlier research
about Triassic-Jurassic transitions inspired the project. Other
co-authors include Koeberl and H. Huber of the University of Vienna,
H.-D. Sues of the Royal Ontario Museum, A. Montanari of the
Osservatorio Geologio do Coldigiocom in Italy, S.J. Fowell of the
University of Alaska-Fairbanks, and M.J. Szajna and B.W. Hartline,
fossil collectors of Reading, Pa.

EDITOR'S NOTE: Professor Kent may be contacted by phone at
(732) 445-2044 or by e-mail at dvk_at_rci.rutgers.edu .
Received on Thu 16 May 2002 05:04:16 PM PDT