Posted on 01/11/2013 7:17:43 PM PST by SeekAndFind
Queensland paleontologists have discovered that the world's only recorded dinosaur stampede is largely made up of the tracks of swimming rather than running animals.
The University of Queensland's (UQ) PhD candidate Anthony Romilio led the study of thousands of small dinosaur tracks at Lark Quarry Conservation Park, central-western Queensland.
Mr Romilio says the 95-98 million-year-old tracks are preserved in thin beds of siltstone and sandstone deposited in a shallow river when the area was part of a vast, forested floodplain.
"Many of the tracks are nothing more than elongated grooves, and probably formed when the claws of swimming dinosaurs scratched the river bottom," Romilio said.
"Some of the more unusual tracks include 'tippy-toe' traces -- this is where fully buoyed dinosaurs made deep, near vertical scratch marks with their toes as they propelled themselves through the water.
"It's difficult to see how tracks such as these could have been made by running or walking animals. "If that was the case we would expect to see a much flatter impression of the foot preserved in the sediment."
Mr Romilio said that similar looking swim traces made by different sized dinosaurs also indicated fluctuations in the depth of the water.
"The smallest swim traces indicate a minimum water depth of about 14 cm, while much larger ones indicate depths of more than 40 cm," Mr Romilio said.
"Unless the water level fluctuated, it's hard to envisage how the different sized swim traces could have been preserved on the one surface.
"Some of the larger tracks are much more consistent with walking animals, and we suspect these dinosaurs were wading through the shallow water."
Mr Romilio said the swimming dinosaur tracks at Lark Quarry belonged to small, two-legged herbivorous dinosaurs known as ornithopods.
(Excerpt) Read more at sciencedaily.com ...
This piece of news gives rise to an interesting question:
How did footprints in water get preserved? Wouldn’t such vulnerable impressions get washed out quickly if made in a shallow river? Wouldn’t dinosaur tracks like this be ubiquitous around the world, in shallow rivers over millions of years? There should have been numerous rivers in the paths of numerous dinosaurs like this.
And what were these dinosaurs running from?
Sorry, but declarative sentences like this should make intelligent people giggle. There is no way any one could possibly know this factual.
The sentence you quote begins with, "Mr. Romilo says," which should tell us (whether we are "intelligent people" or not-so-much), that what follows is Mr. Romilo's opinion.
So, how valid is Mr. Romilo's opinion?
Well, the article tells us that Romilo is a PhD candidate and that he led the study, so we can surmise it's at least an educated opinion.
We might also presume that Romilo found evidence of every characteristic mentioned:
In short, those all appear reasonable conclusions based on scientific evidence -- certainly not, in your words, "known facts", but most likely as close to "known facts" as we will ever get.
How valid is Mr. Romilo's opinion?
Until somebody finds evidence of shoddy workmanship, or some new theory to explain geological features, Romilo's work might well stand the tests of time.
So what is your problem with it?
Note: this topic is from 1/11/2013. Thanks SeekAndFind.
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