[meteorite-list] More Than a Meteor Likely Killed Dinosaurs 65 Million Years Ago

From: E.P. Grondine <epgrondine_at_meteoritecentral.com>
Date: Tue Oct 17 19:25:23 2006
Message-ID: <20061017232519.91252.qmail_at_web36908.mail.mud.yahoo.com>

Hi Ron -

"meteor impact"? Didn't any one at NSF catch this?

Even given this, the header should have read "More
Than One Meteor Likely Killed Dinosaurs 65 Million
Years Ago"

quibble, quibble, quibble,
Ed


--- Ron Baalke <baalke_at_zagami.jpl.nasa.gov> wrote:

>
>
http://www.nsf.gov/news/news_summ.jsp?cntn_id=108103&org=NSF&from=news
>
> National Science Foundation Press Release 06-150
>
> More Than a Meteor Likely Killed Dinosaurs 65
> Million Years Ago
>
> Growing evidence shows a series of natural events
> caused extinction
> October 17, 2006
>
> Growing evidence shows that the dinosaurs and their
> contemporaries were
> not wiped out by the famed Chicxulub meteor impact
> alone, according to a
> paleontologist who says multiple meteor impacts,
> massive volcanism in
> India and climate changes culminated in the end of
> the Cretaceous Period.
>
> The Chicxulub impact may have been the lesser and
> earlier of a series of
> meteor impacts and volcanic eruptions that pounded
> life on Earth for
> more than 500,000 years, say Princeton University
> paleontologist Gerta
> Keller and her collaborators Thierry Adatte from the
> University of
> Neuchatel, Switzerland, and Zsolt Berner and Doris
> Stueben from
> Karlsruhe University in Germany.
>
> A final, much larger and still unidentified impact
> 65.5 million years
> ago appears to have been the last straw, said
> Keller, exterminating
> two-thirds of all species in one of the largest mass
> extinction events
> in the history of life. It's that impact - not
> Chicxulub - that left the
> famous extraterrestrial iridium layer found in rocks
> worldwide that
> marks the impact that finally ended the Age of
> Reptiles, Keller believes.
>
> "The Chicxulub impact alone could not have caused
> the mass extinction,"
> said Keller, "because this impact predates the mass
> extinction."
>
> Keller is scheduled to present that evidence at the
> annual meeting of
> the Geological Society of America (GSA) in
> Philadelphia, on Tuesday,
> October 24, 2006.
>
> "Chicxulub is one of thousands of impact craters on
> Earth's surface and
> in its subsurface," said H. Richard Lane, program
> director in the
> National Science Foundation (NSF) Division of Earth
> Sciences, which
> funded the research. "The evidence found by Keller
> and colleagues
> suggests that there is more to learn about what
> caused the major
> extinction event millions of years ago, and the
> demise of the dinosaurs
> at the end of the Cretaceous."
>
> Marine sediments drilled from the Chicxulub crater
> itself, as well as
> from a site in Texas along the Brazos River and from
> outcrops in
> northeastern Mexico, reveal that Chicxulub hit Earth
> 300,000 years
> before the mass extinction. Microscopic marine
> animals were left
> virtually unscathed, said Keller.
>
> "In all these localities we can analyze their
> microfossils in the
> sediments directly above and below the Chicxulub
> impact layer, and
> cannot find any significant biotic effect," said
> Keller. "We cannot
> attribute any specific extinctions to this impact."
>
> The story that seems to be taking shape, according
> to Keller, is that
> Chicxulub, though violent, actually conspired with
> the prolonged and
> gigantic volcanic eruptions of the Deccan Flood
> Basalts in India, as
> well as with climate change, to nudge species
> towards the brink. They
> were then pushed over with a second large meteor
> impact.
>
> The Deccan volcanism released vast amount of
> greenhouse gases into the
> atmosphere over a period of more than a million
> years leading up to the
> mass extinction. By the time Chicxulub struck, the
> oceans were already
> 3-4 degrees warmer, even at the bottom, Keller said.
>
> "On land it must have been 7-8 degrees warmer," she
> said. "This
> greenhouse warming is well-documented. The
> temperature rise was rapid
> over about 20,000 years, and it stayed warm for
> about 100,000 years,
> then cooled back to normal well before the mass
> extinction."
>
> Where's the crater? "I wish I knew," said Keller.
>
> Scheduled Presentations at the Geological Society of
> America meeting in
> Philadelphia:
>
> "Chixculub Impact and the K/T Mass Extinction"
>
> Pennsylvania Convention Center: 105 AB
>
> Tuesday, 24 October, 2:50 p.m.
>
> "K/T Mass Extinction and the Lilliput Effect:
> Consequences of Impacts,
> Volcanism and Climate Change"
>
> Pennsylvania Convention Center
>
> Wednesday, 25 October, 11:45 a.m.
>
> -NSF-
>
> Media Contacts
> Cheryl Dybas, NSF (703) 292-7734 cdybas_at_nsf.gov
> Ann Cairns, GSA (303) 357-1056
> acairns_at_geosociety.org
>
> Related Websites
> Talk: Chixculub Impact and the K/T Mass Extinction:
> http://www.nsf.gov/news/longurl.cfm?id=14
> Talk: K/T Mass Extinction: Consequences of Impacts:
> http://www.nsf.gov/news/longurl.cfm?id=15
>
> The National Science Foundation (NSF) is an
> independent federal agency
> that supports fundamental research and education
> across all fields of
> science and engineering, with an annual budget of
> $5.58 billion. NSF
> funds reach all 50 states through grants to nearly
> 1,700 universities
> and institutions. Each year, NSF receives about
> 40,000 competitive
> requests for funding, and makes nearly 10,000 new
> funding awards. The
> NSF also awards over $400 million in professional
> and service contracts
> yearly.
>
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Received on Tue 17 Oct 2006 07:25:18 PM PDT