Archaeologica.org

Geologists have found that important rocks from Niagara Gorge -- rock formations that are used to judge the ages of rocks and fossils around North America -- formed five times faster than previously thought. The finding means that scientists will have to re-examine studies of sedimentary rock deposited across North America during the Silurian period, from 416 to 443 million years ago.

The Niagara Gorge rocks were among the first North American rocks to be dated by geologists in the 1800s, and the gorge has been a treasure trove for scientists ever since. From the top of the escarpment, down to the floor of the gorge where the Niagara River cascades, scientists have thought that the gorge represented as much as 10 million years of history.

Cramer's analysis revealed that most of the formations originated during the Ireviken event, which lasted for only 1 million years or so.

Given this new information, the geologists decided that the formations of Niagara Gorge only represent 2 million years of history.

Rock formations there are used as a frame of reference to judge the ages of rocks throughout North America. So these new results mean that many scientists will have to revise their work. Estimates of when certain animals went extinct may change.

"Unfortunately, this means that a lot of people are going to have to re-examine work that they thought was done," Cramer said.