According to new findings published on February 24th in the Proceedings of the National Academy of Sciences, Mars may have been home to sandy beaches and tranquil ocean vistas for tens of millions of years.

A vast ocean may have once existed in the northern pole of Mars for millions of years. Credit: Björn Schreiner : FU Berlin : ESA
A vast ocean may have once existed in the northern pole of Mars for millions of years; Photo: Björn Schreiner/FU Berlin/ESA

The Zhurong Mars rover, which landed in the Utopia Planitia region of Mars in 2021, collected crucial evidence using its high- and low-frequency radar systems. This technology allowed the rover to conduct ground-penetrating scans of the planet’s surface. An international team, which includes Penn State researchers, reviewed its data and concluded they’ve spotted layered structures resembling shorelines on Earth.

“We’re finding places on Mars that used to look like ancient beaches and ancient river deltas,” Benjamin Cardenas, a Penn State assistant professor of geology and study co-author, said in an accompanying statement. “We found evidence for wind, waves, no shortage of sand—a proper, vacation-style beach.”

The research team is particularly examining what appears to be ancient “foreshore deposits.” Foreshore deposits, commonly found on many of Earth’s beaches, are downward-sloping geological formations created by waves as they gradually wash sediment into a large body of water.

“This stood out to us immediately because it suggests there were waves, which means there was a dynamic interface of air and water,” Cardenas added.

The authors of the study suggest that the Martian foreshore deposit angles and sediment thickness fall within the range of those on Earth. Additional analysis showed that the deposits weren’t from volcanic activity, river flows, or wind, which makes oceanic tides the most plausible explanation. This new finding strengthens the hypothesis that an ocean once covered a significant portion of Mars’ northern pole, which may also indicate life may have once existed on the red planet.

“[I]t suggests… there was a dynamic interface of air and water,” Cardenas said. “When we look back at where the earliest life on Earth developed, it was in the interaction between oceans and land, so this is painting a picture of ancient habitable environments, capable of harboring conditions friendly toward microbial life.”