[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]
Re: Age Abstractions
It's curious that the coauthors of previous papers that Roberto cited have
vanished. Perhaps there's a message there?
At 5:12 PM -0700 6/19/07, Jerry D. Harris wrote:
>OK, so it's just an abstract (so far, not counting all that's been published
>on the topic previously), but:
>Fassett, J.E. 2007. The documentation of in-place dinosaur fossils in the
>Paleocene Ojo Alamo Sandstone and Animas Formation in the San Juan Basin of
>New Mexico and Colorado mandates a paradigm shift: dinosaurs can no longer be
>thought of as absolute index fossils for end-Cretaceous strata in the Western
>Interior of North America. New Mexico Geology 29(2):56.
>ABSTRACT: Extensive geochronologic studies of the rocks adjacent to the
>Cretaceous-Tertiary (K-T) interface in the San Juan Basin have now provided
>compelling data attesting to the Paleocene age of the dinosaur-bearing Ojo
>Alamo Sandstone in New Mexico and the Animas Formation in Colorado. These data
>consist of radiometric age determinations for Cretaceous strata underlying the
>K-T interface and palynologic, paleomagnetic, and geochemical evidence
>attesting to the Paleocene age of the strata above the K-T interface. The
>identification of the paleomagnetic normal interval - C29n - in the
>dinosaur-bearing lower part of the Ojo Alamo Sandstone in the southern San
>Juan Basin at multiple localities allows for the precise dating of the last
>occurrence of Paleocene dinosaurs at the top of chron C29n at 64.432 Ma.
> The conventional wisdom (entrenched dogma) among most geologists, and
> especially among vertebrate paleontologists has been, for more than 100
> years, that all dinosaurs became extinct at the end of the Cretaceous. Thus,
> dinosaur bone found in place in a formation provided indisputable evidence
> that the formation was Cretaceous in age. Now, with the discovery of
> Paleocene dinosaurs, the paradigm of Cretaceous-only dinosaurs must shift.
> Let us hope that this paradigm-shift will be a smooth and placid lateral-slip
> along planar fault blocks rather than a grumbling, rumbling, herky-jerky
> sliding of jagged-edged, opposing sides past each other. Science must always
> be conservative and accept such paradigm shifts only on the basis of the most
> solid evidence, however, when the data do finally speak, the shift must be
> accepted by all of us who follow the data in the noble pursuit of finding out
> how the world was made.
>I'd've thought he'd put out a press release...?!?
Jeff Hecht, science & technology writer
525 Auburn St., Auburndale, MA 02466 USA
v. 617-965-3834; fax 617-332-4760