[meteorite-list] Double Meteorite Strike Caused Dinosaur Extinction?

From: Kelly Beatty <jkellybeatty_at_meteoritecentral.com>
Date: Tue, 31 Aug 2010 15:07:08 -0400
Message-ID: <D4B8680CE9244274A973AD91CEF3D1AA_at_NightSkyGuy>

Ron and list...

> Double meteorite strike 'caused dinosaur extinction'
> By Howard Falcon-Lang
> BBC News
> August 27, 2010
>
> The dinosaurs were wiped out 65 million years ago by at least two
> meteorite impacts, rather than a single strike, a new study suggests.


with all due respect to my British science-writing colleagues, this is a
misleading and not very good write-up. Boltysh has been recognized as an impact
since at least the 1970s, and its age has been pegged at 65.2 +/- 0.64 MY since
2002 (Chicxulub is 65.5 MY). the whole "double-whammy" debate played out almost
a decade ago, because the craters' respective age uncertainties left the impact
order unclear.

in any case, Earth gets a new 20-km crater every million years or so, and while
damage from Boltysh would have been significant regionally it wouldn't have had
long-lasting global consequences, if at all.

in fact, the real news is that ferns and flowering plants took hold in the
sediments on the floor of Boltysh *quickly* - 2000 to 5000 years after the
impact (based in part on comparable recoveries from volcanic events) - before
being snuffed out during the K-Pg extinction.

there's no hint in the actual research paper whatsoever that Boltysh somehow
contributed to the K-Pg extinction. rather, the discussion focuses on where
these two impactors might have originated. it wasn't a binary asteroid (not
simultaneous) nor was it likely two random but closely spaced asteroid strikes
(0.01% chance).

I hesitate to suggest where you might go for more details, but you can probably
guess. ;-)


clear skies,
Kelly

****************
J. Kelly Beatty
Senior Contributing Editor
SKY & TELESCOPE
617-416-9991
SkyandTelescope.com
Received on Tue 31 Aug 2010 03:07:08 PM PDT