Diamonds Found In Soil Offer Clue About Comet

January 2, 2009 6:32 a.m. EST

Miami, FL (AHN) - Scientists are saying diamonds found in the soil are proof a large comet exploded above North America almost 13,000 years ago and caused the extinction of many mammal species.

The study, from a group of eight archaeologists and gemologists from the universities of Oregon, California, Northern Arizona University, Oklahoma University and DePaul University, also said the heat from the blast caused a glacier that used to cover the Great Lakes to melt, which caused a massive flood all the way down the Mississippi River.

The cool waves from the glacial floods into the Gulf of Mexico caused currents to change in the Atlantic Ocean, causing a cooling pattern known as the Younger Dryas.

The effects of the comet caused the extinction of several large mammal species, including mammoths, and many early groups of human beings suffered major population declines, according to the study.

The comet was likely part of a "rare swarm" of comets that rained down over the continent 12,900 years ago, according to the researchers.

A much larger comet probably killed off the dinosaurs 65 million years earlier, the scientists said.