Laser-Raman Imaging System Dates Earliest Fossils

LOS ANGELES, March 8 -- A unique laser-Raman imaging system helped scientists substantiate the biological origin of the earliest known cellular fossils at 3.5 billion years ago, as reported this week in the journal Nature.

UCLA paleobiologist J. William Schopf and a team of scientists at the University of Alabama devised the imaging technique to look inside of rocks and determine what they are made of, providing a molecular map.

"This new technique is a tremendous breakthrough, and is something we have sought for 25 years," Schopf said. "Because Raman spectroscopy is nonintrusive, nondestructive and particularly sensitive to the distinctive carbon signal of organic matter of living systems, it is an ideal technique for studies of ancient microscopic fossils. Raman imagery can show a one-to-one correlation between cell shape and chemistry, and prove whether fossils are biological."

Schopf and his colleagues applied the new technique to ancient fossil microbe-like objects, including the oldest specimens reported from the geological record.