New theory offered on dinosaur extinction

PRINCETON, N.J., Sept. 25 (UPI) -- Princeton paleontologist Gerta Keller says she has evidence for yet another theory one what killed off the dinosaurs.

Keller believes the reason for the dinosaurs' demise is much more complicated than the current dominant theory about a single asteroid hitting Earth 65 million years ago.

Keller and her colleagues have uncovered evidence that, rather than a single event, an intensive period of volcanic eruptions, as well as a series of asteroid impacts, likely stressed the worlds' ecosystem to the breaking point.

Scientists say the implications of Keller's ideas extend beyond the dinosaurs since, if she is correct about volcanism, that might influence the way scientists think about the Earth's many episodes of greenhouse warming, which mostly have been caused by periods of volcanic eruptions.

In addition, if the majority of scientists eventually reduce their estimates of the damage done by a single asteroid, that shift in thinking could influence the current-day debate on how much attention should be given to tracking and diverting Earth-bound asteroids and comets in the future.