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Re: dinosaur survived past asteroid impact

LOVE that paper.  Real good detective work in that one.

Lee Hall
Paleontology Undergraduate
Museum of the Rockies
Montana State University
Bozeman, MT

On Sat, Jan 29, 2011 at 8:11 AM, Andrew A. Farke <afarke@gmail.com> wrote:
> On 01/29/2011 06:33 AM, Thomas R. Holtz, Jr. wrote:
>> On Sat, January 29, 2011 2:57 am, Roberto Takata wrote:
>>> How reliable are those results?
>> Not terribly.
> The range on their data is pretty broad, too. The date for the "Paleocene"
> dinosaur bone was 64.8 ą0.9 million years (and the "test" Cretaceous bone
> has similarly broad ranges)! So, anywhere from 63.9 to 65.7 is tenable.
> Compare this with the 65.5 ą 0.3 Ma K-Pg boundary that David mentions (65.2
> - 65.8), and a Paleocene date is hardly convincing. Let's not forget that
> even if the date for the bone is accurate, it only reflects the date when
> the uranium was emplaced in the bone (highly dependent on groundwater
> conditions - may have been 3 years after the bone was buried, may have been
> 300,000). As Tom mentions, the recent comment in PE points out many concerns
> for a Paleocene date on certain fossils from the San Juan Basin.
> Andy
> P.S.: For another great (and oft-neglected) paper on the issue of Paleocene
> dinos in the Western Interior, check out:
> Lofgren, D.L., Hotton, C.L., and Runkel, A.C. 1990. Reworking of Cretaceous
> dinosaurs into Paleocene channel deposits, upper Hell Creek Formation,
> Montana. Geology, 18:874-877.