About 66 million years ago, 70 percent of all the species that existed at the time, including the non-avian dinosaurs, became extinct in an apocalypse widely thought to have been caused by a meteor or comet impact on Mexico’s Yucatan Peninsula. At approximately the same time, a series of volcanic eruptions in Western India produced torrents of lava that discharged large amounts of carbon dioxide and sulfur gas into the atmosphere. In this illustrated lecture, UC-Berkeley geologist Mark Richards will review these remarkable events and explain a radical new theory suggesting they may be causally related. He will also discuss how ongoing research is shedding new light on the true cause(s) of the Cretaceous-Tertiary mass extinction.