Wow Wow... Dinosaurs Survived Mass Extinction By 700,000 Years

[Nandomas]

Dinosaurs Survived Mass Extinction by 700,000 Years, Fossil Find Suggests :)

http://www.sciencedaily.com/releases/2011/01/110127141707.htm

[Xiphactinus]

Dinosaurs Survived Mass Extinction by 700,000 Years, Fossil Find Suggests :)

http://www.sciencedaily.com/releases/2011/01/110127141707.htm

Hmmmm....so this new testing method has a variability of less than 1% (the 700,000 years they are talking about) on a single bone that is 65 million years old? I think that they are sensationalizing this just a wee bit.

[PaleoPastels]

Hahah. Sorry, couldnt help but laughing because the article said "non-avian dinosaurs" when all dinosaurs were terrestrial- there were no dinos that flew or lived in the water. :/ Reminds me of the time I was watching a documentry on Discovery channel and they said "gastropods" were stones that were in sauropod's stomachs to help grind food. haha! Gastroliths! Interesting article, thanks for sharing!

[Fruitbat]

This debate has been going back and forth for a while now. Here are some pertinent articles for those of you who have more than an abiding interest in such things:

Fassett, J.E., et al. (2001). Compelling New Evidence for Paleocene Dinosaurs in the Ojo Alamo Sandstone, San Juan Basin, New Mexico and Colorado, USA. Catastophic Events Conference.

Fassett, J.E. (2008). New Geochronologic and Stratigraphic Evidence Confirms the Paleocene Age of the Dinosaur-Bearing Ojo Alamo Sandstone and Animas Formation in the San Juan Basin, New Mexico and Colorado. Palaeontologia Electronica, Vol.12, Issue 1.

Lucas, S.G., et al. (2009). No Definitive Evidence of Paleocene Dinosaurs in the San Juan Basin. Palaeontologia Electronica, Vol.12, Issue 2.

Fassett, J.E. (2009). Response to Critique by Lucas, et al. (2009) of Paper by Fassett (2009) Documenting Paleocene Dinosaurs in the San Juan Basin. Palaeontologia Electronica, Vol.12, Issue 2.

It's always fun to watch the give and take when a controversial issue is being discussed!!

-Joe

[piranha]

It's always fun to watch the give and take when a controversial issue is being discussed!!

Science must continually press ahead ... some of it sticks and most of it makes for great spirited debate! :eat popcorn:

[jpc]

Hahah. Sorry, couldnt help but laughing because the article said "non-avian dinosaurs" when all dinosaurs were terrestrial- there were no dinos that flew or lived in the water. :/ Reminds me of the time I was watching a documentry on Discovery channel and they said "gastropods" were stones that were in sauropod's stomachs to help grind food. haha! Gastroliths! Interesting article, thanks for sharing!

“non-avian dinosaur “explanation

This is my third attempt. The first time I accidentally went to another website before I posted it. The second time my internet connxn went dead as I posted it. Thirds time’s a charm.

Paleontologists have been using the term “non-avian dinosaurs” ever since Jacques Gauthier’s 1986 paper in which he did a cladistic analysis of birds and dinosaurs and found that birds are actually a group within the dinosaurs. Just as sheep are a group within the mammals. Sheep are indeed mammals because they are part of that larger group. Birds are indeed dinosaurs because e they are part of that larger group. The paper was widely accepted because it has some strong evidence. These papers on the Paleocene dinosaurs in New Mexico are not as well received. As the previous post suggests, there are some arguments against it. Meanwhile, almost all paleontologists consider birds to be dinosaurs, including me. And with all these amazing fossils coming out of Liaoning in China, the evidence is a lot stronger now than it was 25 yrs ago when the paper came out… Yikes and Criminey!!! It’s been 25 yrs!!!

Having said that, when a bird flies by too fast for me to ID it, I do not ask “What was that dinosaur?” I am more likely to say “What was that bird?”

So yes there were and stll are flying dinos.

[PaleoPastels]

Well yeah birds came from dinos! I was taught the theropods did. Sorry, I thought they were refering the the pterosaurs. LOL Anthony just talked to me about Cretaceous birds which helped me understand it better I personally dont consider birds "dinos" because they evolved and became something new and different, just like we arnt "monkeys" we are something more advanced although we share a common ancestor. Although sometimes when im eatin chicken I wonder if this is what a dino tasted like! X'D

[Mexx]

I don't understand the article thoroughly. The uranium-dating method is not new but on of the oldest dating methods, and I am sure numerous other fossils were analysed with that method and seemingly did not yield the same results otherwise they would have been published before.

"Currently, paleontologists date dinosaur fossils using a technique called relative chronology. Where possible, a fossil's age is estimated relative to the known depositional age of a layer of sediment in which it was found or constrained by the known depositional ages of layers above and below the fossil-bearing horizon".

and

" A potential weakness for the relative chronology approach is that over millions of years geologic and environmental forces may cause erosion of a fossil-bearing horizon and therefore a fossil can drift or migrate from its original layer in the strata."

So with this they just want to make their data seem more important because it is a more precise measurement than just derive the age from the age of the geological strata. However, the method U-Pb method is old and has applied numerous times. They hold one set of data agains thousands of consistens sets of data and say they are right....

Also as has been mentioned by someone above the inaccuracy lies between 0.1 and 1% with of the higher case would be about 650'000 years which explains the difference. Furthermore ist was just one single piece of fossil.

"Heaman says it's possible that in some areas the vegetation wasn't wiped out and a number of the hadrosaur species survived"

I also find it highly unlikely that there should have been a restricted area of vegetation still growing during an extinction event of global extension that supported the live of dinosaurs for 700'000 (!) years while uncoupled from the ecological equilibrium of the rest of the world. If hadrosaur survived, also other dinosaurs, especially large predators must have survived. (i.e. no predation to sort out sick and old individuals, spread of diseases, overgrazing would be another problem for survival for such a long time) Taken that plants were still growing there, there must have been sun and when there was sun there should be numerous others places with vegetation hence no extinciton event at all.

Last but not least I find it unlikey that they claim that dinosaurs have survived in New Mexico with is almost as close as it gets to the place where the meteorite most likely hit the earth??

And what about the eggs? I think surviving of the eggs would have been just one in a thousand problems they would have had to face...

[Boesse]

A few points to add here -

1) You can't pick and choose what groups you consider an organism to be. I.e. if you recognize our evolutionary history, then you must recognize the fact that we are a subgroup of old world monkeys. We are just as much old world monkeys as we are mammals, tetrapods, or vertebrates (or, homo, for that matter). Just like you have to accept that birds are no less a dinosaur than a Triceratops is. Technically, there were marine dinosaurs during the Cretaceous - such as the bird Hesperornis.

2) The novelty of the method isn't the dating method itself, but the fact that they dated the bone directly. Instead of dating a layer of volcanic ash with mineral crystals that yield quite a bit of isotopes to sample, this method relies upon dating isotopes in trace-element quantity. When do trace elements first enter the bone? During initial fossilization and diagenesis. How long does that take after the animal dies? Who knows - it can take quite a while.

3) Lucas et al. (2009) responded to a similar article by Fassett (2009). Fassett (2009) reported a hadrosaur skeleton from the Ojo Alamo sandstone, which he seems to think is Paleocene. In fact, there is ample evidence (reviewed in Lucas et al. 2009; previously published evidence, which was known to Fassett and not presented by Lucas et al. but simply reiterated) that the Ojo Alamo Sandstone is much older, and early Maastrichtian at the very youngest (Maastrichtian is the last stage of the late Cretaceous) that Fassett (2009) ignored. Fassett et al. (2011) for some reason chose not to cite the rebuttal by Lucas et al. (2009), perhaps in order to make it seem in his new article that there was less controversy about the age of the Ojo Alamo Sandstone than there really is. In fact, the K/Pg boundary in New Mexico is in one or two formations above the Ojo Alamo.

4) This method basically then does not date the age that the animal died, rather than it does date the age of fossilization. It works great for one of his fossils (within 100,000 kyr of an ash date nearest the fossil) but the other one comes out at 64 something Ma. It dates the age that diagenesis begins, and groundwater bringing trace and rare-earth elements into the bone crystal lattice. The assumption they were under is that diagenesis started very soon after - but it didn't necessarily. There's nothing to say that there can't be quite a lag time between burial and fossilization. So, in essence, these dates can be viewed as minimum dates.

That being said, whatever the hangups are with this method currently, and it clearly isn't reliable now, are the implications it has for the study of paleontology in the future if it is able to be refined. Think about it: one day, a similar method may be able to reliably date individual bones! That would literally revolutionize paleontology.

Bobby

[piranha]

A few points to add here -

1) You can't pick and choose what groups you consider an organism to be. I.e. if you recognize our evolutionary history, then you must recognize the fact that we are a subgroup of old world monkeys. We are just as much old world monkeys as we are mammals, tetrapods, or vertebrates (or, homo, for that matter). Just like you have to accept that birds are no less a dinosaur than a Triceratops is. Technically, there were marine dinosaurs during the Cretaceous - such as the bird Hesperornis.

2) The novelty of the method isn't the dating method itself, but the fact that they dated the bone directly. Instead of dating a layer of volcanic ash with mineral crystals that yield quite a bit of isotopes to sample, this method relies upon dating isotopes in trace-element quantity. When do trace elements first enter the bone? During initial fossilization and diagenesis. How long does that take after the animal dies? Who knows - it can take quite a while.

3) Lucas et al. (2009) responded to a similar article by Fassett (2009). Fassett (2009) reported a hadrosaur skeleton from the Ojo Alamo sandstone, which he seems to think is Paleocene. In fact, there is ample evidence (reviewed in Lucas et al. 2009; previously published evidence, which was known to Fassett and not presented by Lucas et al. but simply reiterated) that the Ojo Alamo Sandstone is much older, and early Maastrichtian at the very youngest (Maastrichtian is the last stage of the late Cretaceous) that Fassett (2009) ignored. Fassett et al. (2011) for some reason chose not to cite the rebuttal by Lucas et al. (2009), perhaps in order to make it seem in his new article that there was less controversy about the age of the Ojo Alamo Sandstone than there really is. In fact, the K/Pg boundary in New Mexico is in one or two formations above the Ojo Alamo.

4) This method basically then does not date the age that the animal died, rather than it does date the age of fossilization. It works great for one of his fossils (within 100,000 kyr of an ash date nearest the fossil) but the other one comes out at 64 something Ma. It dates the age that diagenesis begins, and groundwater bringing trace and rare-earth elements into the bone crystal lattice. The assumption they were under is that diagenesis started very soon after - but it didn't necessarily. There's nothing to say that there can't be quite a lag time between burial and fossilization. So, in essence, these dates can be viewed as minimum dates.

That being said, whatever the hangups are with this method currently, and it clearly isn't reliable now, are the implications it has for the study of paleontology in the future if it is able to be refined. Think about it: one day, a similar method may be able to reliably date individual bones! That would literally revolutionize paleontology.

Bobby

Thank You Bobby ... Magnificent Explanation!

[Boesse]

Yeah guys, no problem - a buddy of mine was actually one of the coauthors for the Lucas et al. (2009) rebuttal, so I've heard an earful about this subject.

Bobby