Meteor did wipe out dinosaurs
20 Jul 2011 by qmjwtjwqdb.d qmjwtjwqdb.d
A newly discovered ceratopsian horn suggests a catastrophic meteor impact did cause the mass extinction of dinosaurs.
A newly discovered ceratopsian horn suggests a catastrophic meteor impact did cause the mass extinction of dinosaurs.
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Three small primitive mammals walk over a Triceratops skeleton, one of the last dinosaurs to exist before the mass extinction that gave way to the age of mammals |
The impact hypothesis – which suggests dinosaurs were wiped out when a massive meteor struck the Earth 65 million years ago – was first suggested 30 years ago. However, palaeontologists failed to find fossils buried within 10 feet of rock below the K-T boundary – the geological layer which marks the transition from the Cretaceous period to the Tertiary period. This anomaly – the “three-metre gap” – led palaeontologist to question whether non-avian dinosaurs gradually went extinct before the meteor struck.
Now, researchers from Yale University have uncovered the fossilised horn of a ceratopsian – likely a Triceratops – in Montana, just five inches below the boundary.
“This discovery suggests the three-metre gap doesn’t exist,” said Tyler Lyson, lead author of the study published in Biology Letters. “The fact that this specimen was so close to the boundary indicates that at least some dinosaurs were doing fine right up until the impact.”
The team can’t determine the exact age of the dinosaur, but it likely lived tens of thousands to just a few thousand years before the impact said Lyson, adding that this discovery provides some evidence that the dinosaurs didn’t slowly die out before the meteor struck.
The team sent soil samples to the lab to determine the exact location of the boundary – which is marked by an abundance of certain types of fossilised pollen and other geological indicators. They thought the fossil was buried within about three feet of the boundary, but were surprised to learn just how close to the boundary – and therefore the impact – it really was.
The team are now examining other fossil specimens that appear to be buried close to the K-T boundary. Lyson suspects that other fossils discovered in the past may have been closer to the boundary that originally thought and that the three-metre gap never existed.
“We should be able to verify that using the more sophisticated soil analysis technique rather than estimating the boundary’s location based solely on visual examination of the rock formations in the field,” Lyson said.
