The largest climate change in central North America since the age of the dinosaurs 65 million years ago, a temperature drop of nearly 15 degrees Fahrenheit, is documented within the fossilized teeth of horses and other plant-eating mammals, a new study reveals.
The overwhelming majority of previous climate-change studies on the 400,000-year transition from the Eocene to the Oligocene epochs, about 33.5 million years ago, focus on marine environments, but University of Florida vertebrate paleontologist Bruce MacFadden and his colleagues turned their attention to fossils from the Great Plains.
“If a temperature change of this magnitude occurred today, Florida would have weather similar to Washington, D.C., or even farther north,” said MacFadden, a curator at the Florida Museum of Natural History.
The Eocene-to-Oligocene transition is known in the fossil record as the Grande Coupure, the “Big Cut” in French, because it marks a massive extinction of life in both marine and land environments. Scientists believe the drop in temperature was likely due to changes in oceanic currents, MacFadden said.
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