International researchers have discovered what they believe to be proof that there were two separate extinction periods during the time of the dinosaurs. Not only were the terrible lizards wiped out by an asteroid, but evidence points to a volcanic event happening "300,000 to 200,000 years before the impact" that caused a greenhouse effect so powerful it killed off seafloor life.
This earlier extinction period is said to have lasted for 100,000 years, according to study lead author Thomas Tobin at the University of Washington. Fossil studies on an island near Antarctica revealed a sediment bed that is thicker than normal for that area which allowed more detailed samples for scientists to construct an accurate timeline. "I think the evidence we have from this location is indicative of two separate events, and also indicates that warming took place," said Tobin.
The research paper will be published in the September 15 issue of the journal "Palaeogeography, Palaeoclimatology, Palaeoecology."
[Image credit: Dinosaur in landscape via Shutterstock]
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