Dinosaurs’ extinction a matter of location, study says
Dinosaurs reigned supreme for more than 160 million years. Their dynasty came to a cataclysmic close 66 million years ago when an asteroid crashed into the Yucatan Peninsula in Mexico at a site now known as the Chicxulub crater, paving the way for mammals — and eventually humans — to inherit the Earth.
But had the extraterrestrial impact happened nearly anywhere else, like in the ocean or in the middle of most continents, it is possible dinosaurs could have survived annihilation, according to a study published Thursday in the journal Scientific Reports.
‘‘I think dinosaurs could still be alive today,’’ if the asteroid had landed elsewhere, said Kunio Kaiho, a paleontologist from Tohoku University in Japan and lead author on the study.
When the asteroid, which had a diameter about half the length of Manhattan, struck the coast of Mexico, it found a rich source of sulfur and hydrocarbons, or organic deposits like fossil fuels, the researchers said. Scorching hot temperatures at the impact crater would have ignited the fuel. The combustion would have spewed soot and sulfur into the stratosphere in sufficient quantities to blot out the sun and change the climate, setting into motion the collapse of entire ecosystems and the extinction of threequarters of all species on Earth.
Not every place on the planet has the same amount of fossil fuel reserves and sulfur trapped beneath its surface. Eighty-seven percent of Earth’s surface, places like most of present day India, China, the Amazon and Africa, would not have had high enough concentrations of
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hydrocarbons to seal the dinosaurs’ fate.
Scientists not involved with the paper criticized the underlying research.
The asteroid impact most likely hurled fiery debris into the sky, which then rained down and ignited firestorms around the world within hours of the crash, said P.S. Gulick, a marine geophysicist from the University of Texas at Austin. The wildfires, he contends, were what released immense amounts