Wednesday, June 20, 2007

Did some dinosaurs survive the K-T event?

Interesting discussion in the world of paleontology today, apparently a study has been published in New Mexico Geology suggesting that dinosaur remains have been found in Paleocene (post-K-T event) layers of rock. Here is the 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.

This thread on the Dinosaur Mailing List (link is to the archives, updated daily) has discussion from the experts. Apparently the author of the new paper has argued for Paleocene dinosaurs before, without much success. It is also pointed out that if there were incontrovertible evidence for this, it would definitely be Science or Nature worthy, and wouldn't be relegated a fairly obscure journal. Every field needs its left-field theorists to keep things interesting, I suppose, and it is at least interesting to hear theories and it's beneficial when they can be proven wrong because it makes us review, analyze, and apply what we do know in order to refute inaccurate claims. That, my friends, is the beauty of science.

That being said, I'm sure the creationists will be flocking to this like ducks to holy water. Weird claims don't annoy me that much as long as they're taken seriously, but the downside is that someone, somewhere, always takes it seriously, it makes me sad for them.

Thanks to John Wilkins at Evolving Thoughts for digging up the story.

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