Posted on 01/22/2009 2:45:42 AM PST by neverdem
Arctic find challenges the idea that the massive reptiles declined slowly.
Fossils uncovered recently in the Arctic support the idea that dinosaurs died off rapidly â perhaps as the result of a massive meteor hitting Earth. The finding contravenes the idea that dinosaurs were already declining by this time.
Geological evidence indicates that an impact occurred near the Yucatán Peninsula at the end of the Cretaceous 66 million years ago. But whether the event created an all-out apocalypse that wiped out the dinosaurs is still a matter of debate. Despite many species dying out, many others survived, including mammals and the small feathered dinosaurs that were the ancestors of today's birds.
Some palaeontologists suggest that non-avian dinosaurs were in decline before the impact â perhaps as a result of major volcanic events or global cooling.
Now, reporting in Naturwissenschaften1, Pascal Godefroit at the Royal Belgian Institute of Natural Sciences and his colleagues describe fossils found in northeastern Russia that suggest dinosaurs were not in decline at all. Although dinosaur fossils have already been found in the Arctic, the new find is unique because of its age: Godefroit and his team have dated the beds at between 68 million and 65 million years old â just before the time of the extinction.
"We found that there is no indication that the biodiversity of dinosaurs decreased just before the [extinction] event," says Godefroit. The team found that herbivorous, duck-billed hadrosaurs and velociraptor-like bipedal theropods seem to be as common as they were in other parts of the planet at the time. Along with this discovery is the presence of the first dinosaur eggshells found in polar regions, hinting that the dinosaurs were residents rather than migrants.
That such healthy polar populations existed just before the extinction would seem to strike a blow against the theory that the animals were already declining. But palaeontologists are cautious.
"The presence of these dinosaurs is certainly concordant with the idea of a sudden extinction, but not incontrovertible evidence for it," says Tom Rich of Museum Victoria in Melbourne, Australia.
Robert Spicer of the Open University's Earth sciences department in Milton Keynes, UK, suggests that when the dinosaurs died out, the site may have lain along the edge of the Arctic Circle rather than deep within it.
"The weak link here is the palaeoposition of the site," he says. "With that said, such diversity even at this latitude suggests that dinosaurs were far more robust than we give them credit for. It makes me ask very serious questions about what could make animals that were resilient enough to live under these conditions suddenly go extinct."
Attributing the extinction to any one cause is risky, adds Bill Clemens of the University of California, Berkeley. Work by David Wake, also at the University of California, Berkeley, and Vance Vredenburg of San Francisco State University2, suggests that the decline of modern amphibians involved a variety of factors ranging from the introduction of predators to disease and habitat loss, Clemens says.
"Ask what is endangering modern amphibians, the answer varies according to species," he adds. "I think the same was probably true with the dinosaurs."
The giant asteroid that crashed into earth 65 million years ago may not have
killed all the dinosaurs.
Meet Polar Dinosaur.
Scientists in Alaska are mining the permafrost along the Colville River for
well-preserved dinosaur bones that suggest dinosaurs were very adaptable
animals. These fossils are found in ancient permafrost beds, suggesting that dinosaurs adapted to cold temperatures.
Dinosaurs living far north of the equator show bulging eyes and brains,
which may be adaptation to low light. Far north dinosaurs like hadrosaurs had skulls filled with hundreds of teeth, perhaps to grind up ferns and horsetails that thrived in colder climates.
There may be something in the discovery that points is the desired direction. If it was ever in the story it was edited to save space. The way the story is written or published, it doesn't make any sense.
It wasn't permafrost at that time. They also find evidence of warm weather plants like ferns.
I’m with you ALL the way!
(I wonder if they have any idea how mortally stupid they reveal/prove themselves to be...)
In geologic terms it is.
Thanks for the ping!
Try this: they couldn't tread water!
3 million years is NOT a sudden extinction. A meteor should have wiped out whatever it was going to wipe out in a century or two. The Darwinists would have it that Man as Human isn’t 3 million years old. It might be “sudden” in a geologic sense but it is not sudden enough to admit of a meteor explanation for the extinction of a whole class of animal life. That explanation is going to have to be narrowed down in time a LOT.
The finding contravenes the idea that dinosaurs were already declining by this time....an idea which was ridiculous on its face. Thanks TXnMA. :')
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I think you may have missed the point about the dates. It is not saying they slowly died out over this period. Rather, the importance of the find is that there was an abundance of animals right up to the point of the Chicxulub impact and not a dwindling of the population preceding the impact.
Cryolophosaurus Ellioti fossil:Here is the femur, upper leg bone, of Cryolophosaurus elliot still trapped in the rock matrix.
The remains of the Cryolophosaurus were found in the Hanson Formation with the remains of a very large prosauropod (related to plateosaurids like the Plateosaurus and Lufengosaurus), a small pterosaur, a mammal-like reptile (a tritylodont, which is a type of synapsid about the size of a rat), and another unknown theropod. There were also fossilized tree trunks two meters away. The site is about 4,000 meters (13,000 feet) above sea level. This supports the idea that, even at high altitudes, early Jurassic Antarctica had forests populated by a diverse range of species, at least along the coast, even though Antarctica was closer to the equator and the world was considerably warmer than today, the climate was still cool temperate. Recent models of Jurassic air flow indicate that coastal areas probably never dropped much below freezing, although more extreme conditions existed inland. Cryolophosaurus was found about 650 kilometers (400 miles) from the South Pole but, at the time it lived, this was about 1000km or so farther north.
fossil tree
frozen sand dunes
Antarctic Ping!
Thanks Fred Nerks.
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