[meteorite-list] Re: Did a Comet Swarm Kill the Dinosaurs?

From: E.P. Grondine <epgrondine_at_meteoritecentral.com>
Date: Thu Apr 22 10:08:26 2004
Message-ID: <20020915185752.85619.qmail_at_web11603.mail.yahoo.com>

Hi all -

If my memory serves me, (I seem to remember that
Pacific Ocean recovery was not a carbonaceous
chondrite), that another comet besides this one may
have hit an asteroid and sent it into the Earth would
seem highly likely -

About every 26 million years or so (the process is
chaotic), when the Earth passes through the plane of
our solar system, The Milky Way, there is an influx of
comets and mass extinctions usually ensue.

I don't know where we are in this impact-extinction
process now, but perhaps the recent cometary impacts
with the Earth amd the impact of Shoemaker-Levy 9 with
Jupiter may have some bearng on this -

ep









--- baalke_at_jpl.nasa.gov wrote:
>
>
http://skyandtelescope.com/news/current/article_738_1.asp
>
> Did a Comet Swarm Kill the Dinosaurs?
> By David Tytell
> Sky & Telescope
> September 13, 2002
>
> In 1991 a modern scientific 'whodunit' was solved
> when
> geologists identified a deeply buried,
> 180-kilometer-wide crater in the
> Yucatán peninsula. Now known as Chicxulub, the scar
> resulted from the impact
> of a 10-km asteroid or comet nucleus 65 million
> years ago that triggered
> global tidal waves, worldwide firestorms, and
> massive earthquakes. When the
> planet finally returned to normal, the dinosaurs and
> the majority of all
> then-living species had gone extinct, paving the way
> for mammals to evolve
> and dominate Earth.
>
> Now a new study suggests that Chicxulub might not
> have been an isolated
> event. Rather, it seems the dinosaurs may have been
> the victims of a one-two
> impact punch.
>
> Simon P. Kelley (Open University, United Kingdom)
> and Eugene Gurov (National
> Academy of Ukraine) reexamined the age of a buried
> 24-km-wide Ukrainian
> crater known as Boltysh. As recently as 1993,
> scientists had determined this
> impact to be 73 million years old. However, through
> a number of isotopic
> experiments, Kelley and Gurov refined that date to
> 65.2 ± 0.6 million years.
> By comparison, Chixculub's age is 65.5 ± 0.6 million
> years.
>
> The overlapping uncertainties strongly suggest, (but
> don't prove) that these
> two impacts occurred simultaneously or nearly so.
> It's "highly probable" the two craters are linked.
>
> Full story here:
>
>
http://skyandtelescope.com/news/current/article_738_1.asp


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Received on Sun 15 Sep 2002 02:57:52 PM PDT