A Volcano Or A Meteor Didn't Kill The Dinosaurs, It Was Both

Despite Michael Crichton’s best efforts, the dinosaurs are still dead after 65 million years. While we know that much, what actually killed them off has been a matter up for continual debate. Some folks argue that the dino’s extinction was caused by a massive meteor impact, while others say massive volcanic eruptions blotted out the sun. Both camps counter by saying there isn’t evidence that either event happened on a large enough scale to spell the death of dinosaurs.

Princeton-led researchers say they know which scenario was the dinosaurs’ death knell: both. A pair of reports from Princeton Professor of Geosciences Gerta Keller’s lab published recently claim a “cosmic one-two punch” of volcanic eruptions and meteor strikes caused the Cretaceous-Tertiary extinction event.

A team led by Keller studied marine sediments from Deccan lava flows that showed population levels of prehistoric plankton species plunged nearly 100 percent in the thousands of years prior to the mass extinction. According to a release, “This eradication occurred in sync with the largest eruption phase of the Deccan Traps — the second of three — when the volcanoes pumped the atmosphere full of climate-altering carbon dioxide and sulfur dioxide.” The research suggests that massive volcanic action did fundamentally change the Earth’s ecosystem at the time of the extinction.

But that wasn’t enough to finish all the dinosaur species off. According to another team in Keller’s lab, a meteor strike likely performed mop-up duties. The team found evidence of such a strike in India. The two events combined, Keller says, led to a long period of wild weather, acid rain and high temperatures that made Earth inhospitable to dinosaurs.

All of this runs counters to the current prevailing theory that a large meteorite impact in Chicxulub in Mexico was large enough to trigger the dinosaur extinction. While that impact is estimated at being 2 million more powerful than a hydrogen bomb(!), Keller has long been a critic of the theory, saying the impact still wasn’t large enough to set off the global extinction event. It’s still a matter open to plenty of debate, but Keller thinks her scenario fits the bill perfectly. For more of the nitty-gritty of her research, click through for Princeton’s rundown on her lab’s work.