Forget outer space, with its comets and aliens: the latest news is that it may have been terrestrial volcanoes that did in the dinos. Gerta Keller, a Princeton paleontologist, showed that a series of volcanic eruptions in an area of western India known as the Deccan Traps likely ended at the time of the K-T extinction, which killed the dinosaurs and many of their pals 65 million years ago.

Keller found that in the hardened marine sediment above the Deccan Traps lava flows, only fossils of creatures postdating the K-T extinction could be found. "So we can say that the flows, which mark the end of the main phase of the Deccan eruptions, ended near the K-T mass extinctions," said Keller.

The volcanoes of the Deccan Traps, in western India, may have wiped out the dinosaurs 65 million years ago.
(Credit: Laszlo Keszthelyi via the University of North Dakota's VolcanoWorld.)

Although most scientists blame the infamous Chicxulub (pronounced CHEEK-shoo-loob) asteroid impact in Mexico's Yucatan peninsula for killing the dinosaurs, there is further evidence that the Deccan Traps did the deed. These explosions were huge: the eruptions would have buried parts of western India in nearly 12,000 feet of volcanic rock, and released up to ten times as much climate-altering gas as li'l old Chicxulub, more even than your neighbor's SUV.

Keller admits that the chronological correlation between K-T and the Deccan eruptions isn't perfect; it could be off by ten thousands years or so. Keller is unsure because the geological record is incomplete. But, she said, "if someone wants to say that this kind of thing has nothing to do with [the] mass extinction— even if it ended 100,000 years earlier— they're out of their mind."

One such crazy is Greg Ravizza of the University of Hawaii. He told National Geographic, "Keller and co-workers prefer an interpretation that concentrates the bulk of the Deccan volcanism very close to the K-T boundary," but that most of the volcanism may have happened well before the extinction.

Keller has previously argued that multiple comet impacts, not just Chicxulub, were responsible for the K-T extinction. She found that Chicxulub made planetfall some 300,000 years before the extinction, and that sediment deposits implied a second comet closer to the K-T boundary.

It's not entirely clear why Keller feels such an urge to go against the grain, but right now it seems that the evidence may be on her side.