Ask someone how the dinosaurs died, and chances are they will tell you about an apocalyptically bad day 66 million years ago, when a huge asteroid slammed into Earth and triggered a nuclear winter. This event left behind distinct traces in the geologic record, as well as a vast crater off Mexico's Yucatán peninsula called Chicxulub. But since the 1980s, researchers have debated whether volcanoes in ancient India may have been an accessory to the mass extinction—or even its main driver.

Now, two independent research teams have created the best time lines of this volcanic activity ever assembled. Despite using different dating methods, their two studies—published on Thursday in the journal Science—agree in broad strokes on the timing