Posted on 06/07/2008 7:53:24 PM PDT by NormsRevenge
Cat-sized reptiles once roamed what is now the icebox of Antarctica, snuggling up in burrows and peeping above ground to snag plant roots and insects.
The evidence for this scenario comes from preserved burrow casts discovered in the Transantarctic Mountains, which extend 3,000 miles (4,800 km) across the polar continent and contain layers of rock dating back 400 million years.
"We've got good evidence that these burrows were made by land-dwelling animals rather than crayfish," said lead researcher Christian Sidor, a vertebrate paleontologist at the University of Washington and curator at UW's Burke Museum of Natural History and Culture.
Ancient digging
About 245 million years ago, floodwaters likely overflowed river banks in parts of Antarctica, sending water and sand across the landscape and into various animal homes, such as burrows. No animal bones or remains were found inside the burrows, suggesting the burrow dweller must have escaped the deluge, according to study researcher Molly Miller of Vanderbilt University.
When the waters receded, the sand inside of these burrows hardened into casts. The largest burrow cast, measuring 14 inches (35 cm) long, 6 inches (16 cm) wide and 3 inches (9 cm) deep, was buried in rock layers of the Wahl Glacier dating back to about 245 million years ago during the Early Triassic period.
"The burrow is an inclined hole and at the end of the burrow the animal would scrape out a larger area and that's where it would huddle down," said Miller, a geologist.
Nine smaller burrow casts previously were discovered in the Allen Hills region in southern Victoria Land and date to the early Middle Triassic. The newly discovered casts predate fossils of tetrapods in the area, pushing back the date for such four-legged vertebrates (animals with backbones) living in Victoria Land by at least 15 million years, Sidor said.
"This would be the earliest record of any kind of tetrapod in that part of Antarctica," Miller told LiveScience.
Burrow dwellers
None of the burrows contained animal remains. However, the burrows' sizes and shapes, along with associated scratch marks, are nearly identical to tetrapod burrows found in South Africa also dating to the Triassic.
One of these South African burrows contained a complete skeleton of an extinct mammal-like reptile called Thrinaxodon liorhinus. The larger burrow from the Wahl Glacier was likely crafted by the same type of animal, Sidor said.
The term "mammal-like reptile" is actually a little misleading. The animals belonging to this group do have a mixture of mammalian and reptilian characteristics, Sidor said, but the group is actually more closely related to mammals than to reptiles. And today's mammals are the living descendants of mammal-like reptiles, he said.
"Thrinaxodon is a distant relative of mammals," Sidor said. "It lived in the Early Triassic whereas the first mammals are Late Triassic/Early Jurassic in age. Thrinaxodon is not related to any specific type of mammals but to mammals in general."
Based on comparisons with other South African burrows, the researchers speculate the smaller burrows in Victoria Land housed mole-sized reptiles called Procolophonids.
"We have documented that tetrapods were burrowing, making dens in Antarctica, back in the Triassic," Sidor said. "There are lots of good reasons for burrowing at high latitudes, not the least of which is protection from the elements."
Different Antarctica
At the time the ancient animals presumably were excavating their subterranean homes, Antarctica would have been ice-free, with a cool temperate climate, Miller said. And Antarctica and southern Africa could have shared residents, since during the Triassic, the two regions were connected as part of the supercontinent Pangea.
The Permian-Triassic extinction had just occurred, and so very few tetrapods existed at the time, with just seven tetrapod genera identified in Antarctica.
Today, no land-based animals live in Antarctica, where temperatures stay below freezing and the earth is covered in ice. (Penguins and seals of Antarctica are dependent on the sea.)
The research, supported by funding from the National Science Foundation, is detailed in the June issue of the Journal of Vertebrate Paleontology.
We could compromise and call them Finks.
Well, that is news to me. I assume you have a source link for that contention, which I believe would also be news to the rest of the world.
Now you’re saying petroleum has the wrong chemical footprint to have an organic source, too?
All hydrocarbon reservoirs show excesses of certain elements or molecules, compared with non hydrocarbon bearing areas. Those include helium, vanadium, elemental carbon, nickel, ferrous iron, sulfides, hopanes in the same narrow carbon isotope range, carbonate cements with a large scatter in the same locality of carbon isotope range, iridium and other heavy elements. Many only in trace amounts, but nevertheless much in excess of their average abundance It would seem very strange that plant debris and primordial petroleum would have swept up the same group of substances. Especially helium, which can only have become concentrated by being washed up from a long pathway - therefore from great depth. Even farmers' water wells that contain an excess of methane frequently also contain an excess of helium.
Thomas Gold
I was afraid you’d use Thomas Gold as a source.
To your credit, you didn’t mention Eugene Island as an example.
There’s a reason 95% of shcool children believe that coal and petroleum have organic sources, which is that only 5% believe quackery. That’s a very good percentage.
You can make a very good case that some of the natural gas (methane) comes from sources other than decayed organic matter which was deposited.
Not most of it, but certainly some of it.
The same can’t be true of petroleum, and it definitely is not true of coal.
The reason some people are resistant to natural organic sources of hydrocarbons and coal is, that despite all the evidence, it doesn’t fit into a young earth model.
Fair enough, it doesn’t. But if you let your model predetermine your facts, that’s not scientific in any way.
I have no desire to “win” the discussion with you. I just wanted to know where you got your information.
If it comes from garbage on the ocean floor that gets folded under at the edges of the continents, then the supply is still endless.
Yeah, settled question.
I think part of the problem is that science tries to establish ‘one’ source for coal, or oil.
There are many different types of coal, and oil.
The reason for that is that they were made from different ‘things’, and different ‘processes’.
All life on Earth is carbon based, and all things ‘return’ to the Earth.
Coal may be formed by the layering of dead animals and plants, after being subjected to heat and pressure.
It is also likely that a stratifying process may take place deeper in the Earth, where elements are subject to unimaginable pressure and temperature.
So, oil, and coal, may come from both sources.
We just don’t know enough about the Earth, to say for sure.
If we did know for sure, then finding it would be a lot more predictable.
(just my thoughts. Not expecting anyone to agree)
Sort of. If we're using it faster than it can be made, and we are, there's a problem.
It’s pretty well understood that coal is formed from the carboniferous forests that existed onshore. We don’t find coal beds that are formed in marine environments ever.
Oil is bit trickier, but it’s nearly 100% marine. The reason it’s trickier is that oil is not usually found in the sediments where it was formed, but has migrated toward the surface to a completely different rock formation which has a seal above it.
Coal can’t do that.
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Gods |
Thanks. Just adding to the catalog, not sending a general distribution, because this looks like it's becoming another bloodbath, and at least one of the participants has an ugly mouth. |
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The holes were made by ancient prehistoric post hole diggers, most likely for telephone poles.
The diggers were 345 feet tall, lived in trees and ate bacon.
“Reptiles at the Mountains of Madness”
I’m not so sure. The proven reserves of oil have never been more than a few years’ supply—because nobody is going to invest what it would take to PROVE a, e.g., 500-years’ supply.
True. Nobody in their right mind would invest money hoping to get it back in 500 years.
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