Mysteriously Rippled Rock Could Mean Ancient Life [VIDEO]
The ripples on a sandy seafloor are clearly caused by the dependable ebb and flow of our ocean's currents. But what about in prehistoric stone? Miniature versions of these ripples are frequently found in fossils - presented in such a way that is not reminiscent of anything seen today. Now, researchers finally believe they have determined what these wrinkles in rock actually are: the "footprints" of ancient microbial life.
"You have about 3 billion years of Earth's history where everything was microbial," expert Tanja Bosak of the Massachusetts Institute of Technology said in a recent statement.
Bosak and her colleagues recently published a study in the journal Nature Geoscience that details exactly how this ancient microbial life formed these ripples.
"It seems [the ripples] become really abundant at the time when early animals were around," Bosak added. "Knowing the mechanism of these features gives us a better sense of the environmental pressures these early animals were experiencing."
According to the study, these sedimentary wrinkles can be found in ancient stone up to 575 million years old - just around the time when the first animals started to appear in the parts of the world now known as Africa, Australia, and the northernmost parts of North America.
Study lead Giulio Mariotti likes to compare these ripples to the footprints of a dinosaur - varied but relatively easy to identify.
"Some of them look like wave ripples, and others look like raindrop impressions," he said.
There is a chance that these "footprints" are actually evidence of ancient sea foam or mysterious tidal patterns not seen today, but the prevailing theory is that an influx of microbial life so intense it created living mats on the seafloor was the actual cause.
As these mats were destroyed or died off, they left microbial aggregates that shifted on the underlying sand, creating wavelike patterns that were later preserved.
According to their study, the team tested this theory by trying to recreate these microbial mats in a controlled environment filled with sand. Sure enough, after a few days, millimeter-wide ripples started appearing in the sand.
Experts following this NASA-supported study suggest the evidence could have significant implications for the most recent Mars rover mission, in which Curiosity has already come upon similar wrinkle structures on the Red Planet. However, a much more in-depth analysis will be needed before coming to any concrete conclusions.
[Credit: Mariotti, Pruss, Perron, Bosak]