Hot springs microbes may help rock dating

CHAMPAIGN, Ill., Jan. 22 (UPI) -- U.S. scientists studying microbes and the growth of sedimentary rock have discovered they can use hot springs microbial records to aid in geological dating.

The University of Illinois researchers said their finding could affect how certain sequences of sedimentary rock are dated, and how scientists might search for evidence of life on other planets.

"We found microbes change the rate at which calcium carbonate precipitates, and that rate controls the chemistry and shape of calcium carbonate crystals," Professor Bruce Fouke said.

"As calcium carbonate is deposited, it leaves a chemical fingerprint of the animals and environment, the plants and bacteria that were there," said Fouke.

The researchers found the rate of precipitation drops drastically when microbes are not present.

"So one of the fingerprints of calcium carbonate deposition that will tell us for sure if there were microbes present at the time it formed is the rate at which it formed," Fouke said.

The study is reported in a paper accepted for publication in the Geological Society of America Bulletin.