New evidence suggests meteorite did not wipe out dinosMay 5th, 2009 - 12:29 pm ICT by ANI
Washington, May 5 (ANI): A geoscientist and her research team from Princeton University have compiled new evidence disproving a popular theory that an asteroid wiped out the dinosaurs about 65 million years ago.
Gerta Keller, the scientist in question, whose studies of rock formations at many sites in the United States, Mexico and India have led her to conclude that volcanoes, not a vast meteorite, were the more likely culprits in the demise of the Earth’s giant reptiles, is producing new data supporting her claim.
Examinations at several new sites have produced “biotic evidence” - the fossilized traces of plants and animals tied to the period in question - indicating that a massive die-off did not occur directly after the strike but much later.
In addition, Keller and other researchers have found “aftermath” sediments that remained undisturbed and showed signs of active life, with burrows formed by creatures colonizing the ocean floor.
This would quash a theory advanced by some that a massive tsunami followed the impact, according to Keller.
“Careful documentation of results that are reproducible and verifiable will uncover what really happened,” Keller said. “This study takes an important step in that direction,” she added.
Much of the new data comes from a trench dug out of low-lying hills in northeastern Mexico at a site called El Penon.
A group of Princeton undergraduates, including Richard Lease and Steven Andrews, accompanying Princeton Professor Gerta Keller on a field trip to Mexico in 2004 excavated the area and uncovered the new evidence.
Keller and her team have been analyzing that evidence for the last several years.
She discovered that the evidence for the asteroid theory was not so clear.
In field investigations, she and her team of students and collaborators found populations of Cretaceous age foraminifera, one-celled ocean organisms that evolved rapidly during select geological periods, living on top of the impact fallout from Chicxulub.
The fallout from the asteroid that struck Chicxulub is visible as a layer of glassy beads of molten rock that rained down after the impact.
If this impact caused the mass extinction, then the foraminifera above the impact glass beads should have been the newly evolved species of the Tertiary age.
Using these fossil remains to construct a timeline, she and her team were able to date the surrounding geologic features and begin to piece together proof that the impact occurred 300,000 years before the great extinction. (ANI)
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