BUKAMATA – An asteroid that killed almost all dinosaurs in the past hit Earth during the spring. That’s according to new research.
To reach their conclusion, the researchers searched parts of North Dakota in the US for fossils of paddlefish and sturgeon that were killed when the asteroid hit Earth.
They used powerful X-rays and carbon isotope recordings of the bones of fish that died less than an hour after the asteroid hit.
Carbon isotopes act as tracers to find out how carbon atoms have changed over the years.
They found the impact shock caused huge waves of water that moved sediment, swallowed the fish and buried them alive.
“Carbon isotope signals throughout this poor paddlefish growth record confirm that the feeding season has not yet reached its climax – death comes in the spring,” said Melanie During, lead author of the University of Uppsala.
The team found that the fish fossils are well-preserved, with their bones showing barely any signs of chemical change and the soft tissues still intact.
Experts look at how the fish bones grow to determine the season in which they die.
One of the paddlefishes also underwent carbon isotope analysis to reveal its annual diet.
The availability of zooplankton, which it favors, is at its peak between spring and summer, leading the researchers to their findings.
The team said their conclusion could help explain why some animals, including birds, crocodiles and turtles, survived the asteroid impact 66 million years ago.
Southern Hemisphere fall coincides with Northern Hemisphere spring, which means preparations for winter may have protected the Southern Hemisphere’s animals.
“This important finding will help reveal why most dinosaurs died out while early birds and mammals managed to avoid extinction.”
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