for National Geographic News
A series of gargantuan volcanic eruptions may have ended at nearly the same time that the dinosaurs went extinct, a new study shows.
The find bolsters a controversial theory that massive volcanism contributed to the global catastrophe known as the K-T extinction, which wiped out the dinosaurs and many of Earth's other organisms 65 million years ago.
Gerta Keller, a Princeton University paleontologist, presented the new research last week at a meeting of the Geological Society of America in Denver, Colorado.
She found that underwater portions of the ancient lava flows, known as the Deccan Traps, contained marine fossils only of species known to have existed after the extinctions.
In other words, all of the marine sediments that built up on the lava flows came from after the extinction.
"So we can say that the flows, which mark the end of the main phase, of the Deccan eruptions ended near the K-T mass extinctions," she said.
For years, Keller and a few other scientists have suspected that the Deccan Traps played a role in the global catastrophe.
The eruptions would have been on a scale that dwarfed anything ever experienced by humans, burying parts of western India in nearly 12,000 feet (3,500 meters) of volcanic rock, they say.
The effects worldwide would have been even worse, Keller said. Each of the flows would have released vast quantities of climate-altering gases—up to ten times as much as were produced by the famed Chicxulub asteroid impact in Mexico's Yucatan peninsula. Most scientists believe the Chicxulub impact is the major cause of the dino die-off.
The Deccan Traps devastation would also have occurred quickly.
"Each of these megaflows could have been formed in weeks, months, or years," Keller said, citing a study by French scientists.
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