A research team led by scientists at Australia's Curtin University of Technology found high concentrations of carbon 12, associated with organic life, in 4.2 billion-year-old diamonds from Jack Hills in western Australia, the university said Wednesday in a release.

"We believe this find to be the oldest terrestrial light carbon reservoir discovered so far," project leader Alexander Nemchin said.

He said the finding suggests a simple life form existed on Earth 700 million years earlier than previously thought.

The findings are published in the journal Nature.

"The discovery challenges our fundamental understanding of processes active in the early history of the Earth," Nemchin said. "It suggests that life may well have appeared on Earth long before the period of heavy-meteorite bombardment believed by some to have initiated the emergence of life on Earth."