By IANS
New York : There is a new theory about the most persistent paleontological murder mystery – the death of dinosaurs – and it has an India angle.
A Princeton University researcher believes that a series of huge volcanic eruptions in India may have killed off dinosaurs 65 million years ago — not a meteor impact in the Gulf of Mexico, as widely believed.
Paleontologist Gerta Keller believes the eruptions, which created the gigantic Deccan Traps lava beds, caused dinosaurs to die out.
Keller, who conducted a slew of new investigations to pin down the time of the eruptions, said: “It’s the first time we can directly link the main phase of the Deccan Traps to the mass extinction.”
Keller presented the new findings Tuesday at the annual meeting of the Geological Society of America in Denver.
The main phase of the Deccan eruptions spewed 80 percent of the lava that spread out for hundreds of miles. It is calculated to have released ten times more climate altering gases into the atmosphere than the nearly concurrent Chicxulub meteor impact in Mexico.
The crucial link between the eruption and the mass extinction comes in the form of microscopic marine fossils that are known to have evolved immediately after the mysterious mass extinction event.
The same telltale fossilized planktonic foraminifera were found at Rajahmundry near the Bay of Bengal, about 1,000 km from the centre of the Deccan Traps.
At Rajahmundry there are two lava “traps” containing four layers of lava each. Between the traps are about nine meters of marine sediments. Those sediments just above the lower trap, which was the mammoth main phase, contain the incriminating microfossils.
Previous work had narrowed the Deccan eruption timing to within 800,000 years of the extinction event.
Subsequent radiometric dating of argon and potassium isotopes in minerals narrowed the age to within 300,000 years of the 65-million-year-old Cretaceous-Tertiary boundary, sometimes called the K-T boundary.
The microfossils are far more specific, however, because they demonstrate directly that the biggest phase of the eruption ended right when the aftermath of the mass extinction event began. That sort of clear-cut timing has been a lot tougher to pin down with Chicxulub-related sediments, which predate the mass extinction.
“Our results are consistent and mutually supportive with a number of new studies… that reveal a very short time for the main Deccan eruptions at or near the K-T boundary and the massive carbon dioxide and sulfur dioxide output of each major eruption that dwarfs the output of Chicxulub,” explained Keller.
“Our K-T age control combined with these results strongly points to Deccan volcanism as the likely leading contender in the K-T mass extinction.”