That’s according to an international research team that studied the Chicxulub meteor impact, LiveScience reports.
These gigantic eruptions formed the Deccan Traps, which sprang up in a series of massive lava flows that once covered large areas of India.. Over a span of several million years, the lava spewed forth from numerous fractures and the molten rock bubbled forth from a mantle plume, an enormous blob of magma beneath the Earth’s crust. The eruptions began long before the Chicxulub impact and continued long after the meteor struck the earth, LiveScience reports. The impact crater from this asteroid is found in Mexico’s Yucatan peninsula.
It had been thought that there was an “uncomfortably close” coincidence between the eruptions at the Deccan Traps and the impact according to the UC Berkeley News Center.
“If you try to explain why the largest impact we know of in the last billion years happened within 100,000 years of these massive lava flows at Deccan … the chances of that occurring at random are minuscule,” team leader Mark Richards, a UC Berkeley professor of earth and planetary science said. “It’s not a very credible coincidence.”
These prolific lava flows likely emitted voluminous amounts of carbon dioxide and other toxic, climate-modifying gases into the atmosphere, but it’s not really known if this contributed to the demise of the dinosaurs and most other life on Earth, Richards said.
“This connection between the impact and the Deccan lava flows is a great story and might even be true, but it doesn’t yet take us closer to understanding what actually killed the dinosaurs and the ‘forams'” he said. “Forams” refers to foraminiferans — tiny marine creatures. Many of these creatures vanished from the fossil record rapidly at the boundary between the Cretaceous and Tertiary periods, commonly called the KT boundary. The extinction of the dinosaurs is largely credited with ushering in the age of mammals, including us.
In 1989, Richards had proposed that plumes of hot rock, known as “plume heads,” travel up through Earth’s mantle every 20-30 million years, generating massive lava flows, or basalts, as they are known, such as the Deccan Traps, EarthSky reports. He thought it was more than coincidence that the last four out of six known mass extinctions occurred more or less simultaneously as one of these massive eruptions.
So he joined forces with other experts at UC Berkeley to see if there were any holes in his idea that the impact triggered the Deccan eruptions. Instead, the team found plenty of supporting evidence.
His colleague, Paul Renne of the Berkeley Geochronology Center re-dated the impact of the asteroid and mass extinction, and found that they were simultaneous, likely occurring within about 100,000 years of the largest Deccan eruptions.
Another co-author of the study, Michael Manga, of UC Cal Berkeley, showed that really large earthquakes could bring about volcanic eruptions, and the earthquake from the asteroid impact shook the entire planet. It was large enough to ignite the Deccan flood basalts as well as other places worldwide, including mid-ocean ridges.
“It’s inconceivable that the impact could have melted a whole lot of rock away from the impact site itself, but if you had a system that already had magma and you gave it a little extra kick, it could produce a big eruption,” Manga said.
The scientists traveled to India in April 2014 to collect lava samples for dating.
His conclusion?
“This was an existing massive volcanic system that had been there probably several million years, and the impact gave this thing a shake and it mobilized a huge amount of magma over a short amount of time.”
UC Berkeley News Center reports that after the research team’s paper was accepted for publication, a group from Princeton University published new radioisotopic dates for the Deccan Traps lava. Their findings are consistent with the predictions made by Richards’ team.
This discovery gives scientists a more complete picture of what led to the demise of the dinosaurs.
The scientist’s findings were published in The Geological Society of America Bulletin.
