Volcanic gas bursts probably didn’t kill off the dinosaurs
Massive gas bursts emitted by volcanoes about 66 million years ago probably couldn’t have caused a mass extinction event that spelled doom for all nonbird dinosaurs, new research suggests. Data on ancient temperatures, combined with simulations of the shifting carbon cycle in the ocean, lend support to the hypothesis that a giant asteroid impact — not toxic gases emitted by Deccan Traps eruption — was primarily responsible for the die-off, researchers report January 17 in Science. About three-quarters of Earth’s plant and animal species were killed off during the extinction event at the end of the Cretaceous Period. Sediment deposits linked to the giant asteroid impact, which struck Chicxulub in what now Mexico’s Yucatan peninsula, form a layer known as the “KPg” boundary. This boundary marks the transition from the Cretaceous to the Paleogene Period, and implicates the asteroid strike in the extinction event (SN: 1/25/17). But the Deccan Traps eruptions, which spewed as much as 500,000 cubic kilometers of lava across much of...