Posted on 01/27/2011 11:05:42 AM PST by decimon
University of Alberta researchers determined that a fossilized dinosaur bone found in New Mexico confounds the long established paradigm that the age of dinosaurs ended between 65.5 and 66 million years ago.
The U of A team, led by Larry Heaman from the Department of Earth and Atmospheric Sciences, determined the femur bone of a hadrosaur as being only 64.8 million years old. That means this particular plant eater was alive about 700,000 years after the mass extinction event many paleontologists believe wiped all non-avian dinosaurs off the face of earth, forever.
Heaman and colleagues used a new direct-dating method called U-Pb (uranium-lead) dating. A laser beam unseats minute particles of the fossil, which then undergo isotopic analysis. This new technique not only allows the age of fossil bone to be determined but potentially can distinguish the type of food a dinosaur eats. Living bone contains very low levels of uranium but during fossilization (typically less than 1000 years after death) bone is enriched in elements like uranium. The uranium atoms in bone decay spontaneously to lead over time and once fossilization is complete the uranium-lead clock starts ticking. The isotopic composition of lead determined in the hadrosaur's femur bone is therefore a measure of its absolute age.
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. However, obtaining accurate depositional ages for sedimentary rocks is very difficult and as a consequence the depositional age of most fossil horizons is poorly constrained. 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. The researchers say their direct-dating method precludes the reworking process.
It's widely believed that a mass extinction of the dinosaurs happened between 65.5 and 66 million years ago. It's commonly believed debris from a giant meteorite impact blocked out the Sun, causing extreme climate conditions and killing vegetation worldwide.
Heaman and his research colleagues say there could be several reasons why the New Mexico hadrosaur came from a line of dinosaurs that survived the great mass extinction events of the late Cretaceous period (KT extinction event). Heaman says it's possible that in some areas the vegetation wasn't wiped out and a number of the hadrosaur species survived. The researchers also say the potential survival of dinosaur eggs during extreme climatic conditions needs to be explored.
Heaman and his colleagues believe if their new uranium-lead dating technique bears out on more fossil samples then the KT extinction paradigm and the end of the dinosaurs will have to be revised.
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The research was published online, January 26, in the journal, Geology.
[ Alternatively the fellows who kept track of the dinosaur parks on Earth came around to do a survey and found all their animals had been killed ~ so, being good stewards, they brought in some newbies!
They came back 32.785 million years later on their regularly scheduled rounds only to find that LOCAL FAUNA had taken over and eaten all their hadrasaurs. They got so upset they nuked half the new animals. ]
Nah, we invent time machines and an apettite for dino burgers and we rationalize it by saying we can only kill dinos for meat as long as it is after the K-T event....
Hmm ~ frame dragging would rule that out ~ besides, they all taste rancid like they’re full of decomposing fat.
I am a professional scientist, and so understanding what happened 64.5 million years ago is very relevant to my interests and needed in my sphere of relevant knowledge.
The implications are nothing short of incredible.
We are proving LIFE AFTER DEATH among Hadrasaurs.
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To: Brian S. Fitzgerald
I’m so glad it’s not just me. I posted something and it reposted 40 times!
I call BS. We know now that radioactive decay is not a constant, and seems to be influenced by solar cycles. I'll bet these fluctuations in the isotopic decay rates aren't figured into the age estimate. In fact, I don't think they can be, because we just discovered the effect and have no idea how long or broad it is.
If you knew anything about dating, you would now that they do NOT use carbon dating for these time periods.
I call BS. We know now that radioactive decay is not a constant, and seems to be influenced by solar cycles. I'll bet these fluctuations in the isotopic decay rates aren't figured into the age estimate.
OK. Even if you give it a 25% accuracy, it is still closer to 700k years than it is to 6k years.
I used the words:
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with the Yahoo search option and that thread showed up.
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Why? Because the ability to measure isn't that precise. Even if the measurement is as close as 500,000 years, it might as well be an eternity. Because in reality that is what 500,00, a million, 65,000,000 years are.
If you knew anything about dating, you would now that they do NOT use carbon dating for these time periods.
Since I do know anything about dating, you and I will have to assume that my quip was intended for non-idiots as a comedic introduction to the post.
OK. Even if you give it a 25% accuracy, it is still closer to 700k years than it is to 6k years.
Who said anything about 6k years?
I made the statement that this 700k year date estimation is provably unsupportable and cited why.
Now put down the crack pipe, you're making a real fool of yourself.
It makes a huge difference to our concept of reality, the history of the Earth, and our place in the universe.
Things seem pretty stable to us, and we think things may well continue on as they have for a few more thousand years; but the lesson of the dinosaurs is that something can happen that will wipe it all away!
Maybe knowing that our time on this planet has been rather short in comparison to how long the Earth has been here will give us some much needed humility.
You may well think it doesn’t make any difference in your life, but for those of us who are intellectually curious and seek answers......
Beats squatting in a cave waiting for the other guy to tame fire.
It is not unreasonable to consider that not all dinosaurs were killed immediately. However, so many died that the scurrying little mammals were able to begin to grow and multiply, and probably ate up all the hadrosaur and other eggs that might have been produced after the big disaster, ultimately causing them to die out. In our lifetime we had the teaming passenger pigeons that were destroyed once their breeding population fell too low. It appeared that they needed a certain sized flock to stimulate their reproductive hormones. Perhaps the social dinosaurs had a similar mechanism and once their numbers were reduced they no longer were able to breed.
I think that is a very likely theory. Still, the Dodo hung on for generations in that precarious “endangered” position so I have no problem thinking some dino’s did too.
Now they have retest all the previous findings if all that has changed is the dating method.
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