Geophysicists from the University of California, Berkeley now believe that the asteroid that slammed into the ocean off the coast of Mexico some 66 million years ago killing the dinosaurs may have also triggered volcanic eruptions around the globe that may have contributed to the devastation of the planet.
More specifically, the impact triggered some of the most immense eruptions of lava in the Deccan Traps, located in India. Researchers explain the "uncomfortably close" coincidence of the eruptions in the Deccan Traps that have always cast doubt on the impact theory being the sole cause of the end causing the Cretaceous mass extinction event.
"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," said team leader Mark Richards, UC Berkeley professor of earth and planetary science. "It's not a very credible coincidence."
The Deccan lava flows actually began before the asteroid impact, but they continued to erupt for several hundred years after re-ignition and most likely resulted in tremendous amounts of carbon dioxide and other noxious, climate altering gases being released into the atmosphere, although it is still unclear if this contributed to the demise of most of the life on Earth that ended the Age of Dinosaurs.
"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, referring to tiny sea creatures called foraminifera, many of which disappeared from the fossil record virtually overnight at the boundary between the Cretaceous and Tertiary periods, called the KT boundary.
Richards teamed with experts to discover the truth. Paul Renne, a professor in residence in the UC Berkeley Department of Earth and Planetary Science and director of the Berkeley Geochronology Center, redated the asteroid impact and mass extinction two years ago and found them essentially simultaneous, but also within approximately 100,000 years of the largest Deccan eruptions, referred to as the Wai subgroup flows, which produced about 70 percent of the lavas that now stretch across the Indian subcontinent from Mumbai to Kolkata. Michael Manga, a professor in the same department, has shown over the past decade that large earthquakes - equivalent to Japan's 9.0 Tohoku quake in 2011 - can trigger nearby volcanic eruptions.
Richards and Renne along with graduate student Courtney Sprain paid a visit to India in April 2014 to obtain lava samples for dating and noticed the surfaces showed weathering, marking the onset of huge Wai subgroup flows.
"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," Richards said. "The beauty of this theory is that it is very testable, because it predicts that you should have the impact and the beginning of the extinction, and within 100,000 years or so you should have these massive eruptions coming out, which is about how long it might take for the magma to reach the surface."
