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Re: Double impact at K-T boundary ?

The original Shiva crater papers are:

Nayak, V.K. 2002. A Meteorite Impact Crater and Astroblemes in India. Lunar & Planetary Science abstract 1129.

Chatterjee, S., N. Guven, A. Yoshinobu, & R. Donofrio. 2006. Shiva Structure: a possible KT boundary impact crater on the western shelf of India. Museum of Texas Tech University Special Publications 50:39 p.

Peter Moon


----- Original Message ----- From: "Erik Boehm" <erikboehm07@yahoo.com>
To: <dinosaur@usc.edu>; <gmajumdar@freeuk.com>
Sent: Friday, August 27, 2010 7:26 PM
Subject: Re: Double impact at K-T boundary ?

So then.....
The Dinos would have had to make it through THREE?! impact events if they were to make it to the present?
Well, the Avian lineage managed, too bad about the rest.


--- On Fri, 8/27/10, Gautam Majumdar <gmajumdar@freeuk.com> wrote:

From: Gautam Majumdar <gmajumdar@freeuk.com>
Subject: Double impact at K-T boundary ?
To: dinosaur@usc.edu
Date: Friday, August 27, 2010, 1:55 PM
Geology 2010; 38:
835-38 doi: 10.1130/G31034.1


The end-Cretaceous mass extinction has been attributed by
most to a single
asteroid impact at Chicxulub on the Yucatán Peninsula,
Mexico. The discovery
of a second smaller crater with a similar age at Boltysh in
the Ukraine has
raised the possibility that a shower of asteroids or comets
impacted Earth
close to the Cretaceous-Paleogene (K-Pg) boundary. Here we
palynological and delta-13C evidence from crater-fill
sediments in the . Our
analyses demonstrate that a post-impact flora, formed on
the ejecta layer, was
in turn devastated by the K-Pg event. The sequence of
floral recovery from the
K-Pg event is directly comparable with that in middle North
America. We
conclude that the Boltysh crater predated Chicxulub by ~
2-5 k.y., a time
scale that constrains the likely origin of the bodies that
formed the two
known K-Pg craters.

Interestingly a double impact was proposed by Wolfe in

Palaeobotanical evidence for June 'impact winter' at the
boundary, Nature 1991; 352: 420-2