01/16/2009 05:12 am ET Updated May 25, 2011

Volcanoes Killed The Dinosaurs, New Evidence Suggests

Accepted theory holds that the dinosaurs became extinct after a large asteroid crashed into Earth, rending the environment uninhabitable. However, that theory is facing a serious challenge as evidence mounts that it may have been massive volcanic eruptions in India that ended the species:

Huge volcanic eruptions that belched sulfur into the air for around 10,000 years could have killed the dinosaurs, according to new evidence unearthed by geologists.

Evidence is accumulating that it wasn't an asteroid that did the beasts in, but volcanoes -- the first real challenge the extinction theory has met in three decades.

A combination of studies on dinosaur fossils, magnetic signatures in rocks and the timing of the disappearance of different species suggest it was volcanoes, not an asteroid, that caused the dinosaurs' extinction.

"We're discovering ... amazingly large flows, amazingly short time scales and amazing volcanic (eruptions)," said Vincent Courtillot of the University of Paris, who is is presenting new evidence for the volcano theory this week at the American Geophysical Union conference here.

In related news, scientists have discovered new dinosaurs in the Sahara desert, in what they deem to be an astonishing prehistoric "river of the giants":

A prehistoric 'river of the giants' that was once home to gigantic fish, towering dinosaurs and 60 foot long crocodiles has been unearthed by British fossil hunters.

The river - as wide as the Danube - flowed across the Sahara desert 100 million years ago, surrounded by lush forests, waterways and lakes.

The site has yielded some of the most exciting African prehistoric finds in years - including the tip of a giant flying reptile's beak and a limb bone from a 65 foot long plant-eating dinosaur. Both are thought to be new species.

Other finds include the remains of a crocodile the length of two double deckers, two inch long scales shed by an freshwater predatory fish, and teeth from a massive sawfish.

Rare dinosaur footprints were also found at the site, near the Algerian border in south-east Morocco.