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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
lhall@montana.edu
http://sites.google.com/site/leehallpaleo/Home




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.
>