Re: dinosaur survived past asteroid impact

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

On Sat, January 29, 2011 2:57 am, Roberto Takata wrote:
> How reliable are those results?
>
> []s,
>
> Roberto Takata
>
> On Sat, Jan 29, 2011 at 2:25 AM, Ian Paulsen <birdbooker@zipcon.net>
> wrote:
>> HI:
>>  Only by 700,000 years though:
>>
>> http://www.canada.com/technology/Bone+discovery+suggests+dinosaurs+survived+years+past+meteorite+strike/4187835/story.html
>>

Not terribly.

For one thing (already addressed by someone else), there is the
problematic nature of using an untried technique on a problematic
situation, rather than first verifying it on fossils for which the age
dates are well-constrained. Make sure that your tool actually gives you
good results FIRST, then use it for the problem.

Then there are problems with the stratigraphic situation of the bone in
question anyway: http://palaeo-electronica.org/2009_2/199/index.html

Yet another problem (which I haven't seen yet) is that bone is notoriously
good at picking up uranium-rich minerals like uraninite post-deposition.
The early days of the US, Indian, and Pakistani nuclear programs all made
use of a lot of fossil bone (Morrison dinosaurs for US, Sivalik mammals
for the south Asian ones) in order to process enough uranium. So the
possibility that they are age dating the time of permineralization rather
than the time of deposition of the fossil has to be considered.

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