RE: K-Pg extinction global firestorms

["Thomas R. Holtz, Jr." <tholtz@umd.edu>]

People in the geological community have been underwhelmed by the "it was a 
comet, not an asteroid" presentation for methodological
reasons. It requires us to be able to know within a few 10%s the relative 
contribution of the impactor and the impact site, but
there are so many uncontrolled variables the uncertainty is currently greater 
than the differences required between the two models.

Thomas R. Holtz, Jr.
Email: tholtz@umd.edu   Phone: 301-405-4084
Office: Centreville 1216                        
Senior Lecturer, Vertebrate Paleontology
Dept. of Geology, University of Maryland
http://www.geol.umd.edu/~tholtz/
Fax: 301-314-9661               

Faculty Director, Science & Global Change Program, College Park Scholars
http://www.geol.umd.edu/sgc
Fax: 301-314-9843

Mailing Address:        Thomas R. Holtz, Jr.
                        Department of Geology
                        Building 237, Room 1117
                        University of Maryland
                        College Park, MD 20742 USA
> -----Original Message-----
> From: owner-DINOSAUR@usc.edu [mailto:owner-DINOSAUR@usc.edu] On Behalf Of 
> Richard W. Travsky
> Sent: Friday, March 29, 2013 10:56 AM
> To: dinosaur@usc.edu
> Subject: Re: K-Pg extinction global firestorms
> 
> 
> 
> On Wed, 27 Mar 2013, Ben Creisler wrote:
> >
> > A new paper of interest:
> >
> > Douglas S. Robertson, William M. Lewis, Peter M. Sheehan & Owen B.
> > Toon (2013) K-Pg extinction: Reevaluation of the heat-fire hypothesis.
> > Journal of Geophysical Research: Biogeosciences (advance online
> > publication)
> > DOI: 10.1002/jgrg.20018
> > http://onlinelibrary.wiley.com/doi/10.1002/jgrg.20018/abstract
> 
> So, what about the other recent news that it could have been a comet? That 
> has a different composition from, say, an asteroid. It
> would seem to rule out a comet.