Hidden Shores: China’s Zhurong Rover Uncovers Ancient Martian Beach

For decades, scientists have speculated that Mars—now a dry, frigid desert—was once home to oceans and a more Earth-like climate. Now, compelling new data from China’s Zhurong rover may offer the strongest evidence yet: signs of a long-lost beach buried beneath the Martian surface.

Zhurong rover

Using ground-penetrating radar, the Zhurong rover—part of China’s Tianwen-1 mission—scanned up to 80 meters beneath Mars' Utopia Planitia region, a massive impact basin believed to once host a vast ocean. What it found were layers of sand and sediment sloping upward, arranged in patterns remarkably similar to coastal deposits here on Earth.

The buried formations, located about 10 meters below the dusty surface, show a gentle 15-degree incline, aligned in a way that mirrors the possible shoreline of this ancient Martian sea. Researchers believe these formations could only have been created by waves and sediment flow over millions of years, further supporting the theory of a long-standing body of water.

“These aren’t dunes, lava flows, or impact remnants,” said planetary scientist Michael Manga from the University of California, Berkeley. “Their layout and slope are consistent with what you’d expect from a shoreline.”

The discovery is significant not just for its geological implications—it also adds weight to the ongoing question of past life on Mars. On Earth, shallow coastal regions like this are considered prime real estate for early microbial life. As Benjamin Cardenas of Penn State noted, “The interface of air, water, and land is where some of the earliest life on our planet likely began.”

Zhurong’s year-long mission, from May 2021 to May 2022, covered about 1.9 kilometers, tracing the edge of a rocky escarpment within the 3,300-kilometer-wide Utopia Basin—the largest known impact crater in our solar system. The radar data it transmitted back revealed buried sandy structures that appear preserved by time and shielded from erosion by layers of debris, possibly from volcanic ash or meteor impacts.

The origin of these beaches stretches back about four billion years, to a time when Mars had a thicker atmosphere and a warmer climate, conditions capable of supporting liquid water on the surface.

Interestingly, this new evidence helps resolve an old puzzle. Images captured by NASA's Viking mission in the 1970s suggested a massive ocean, but the supposed shoreline appeared uneven—some parts were thousands of meters higher than others. Scientists now believe that Mars’ massive Tharsis volcanic region caused shifts in the planet’s rotation and surface shape, distorting what would have once been a level coastline.

As Mars’ atmosphere slowly thinned, much of its water is thought to have either escaped into space or migrated underground, where it remains locked in ice or chemically bound in minerals.

The beach uncovered by Zhurong may be the best-preserved evidence so far that Mars wasn’t always the Red Planet as we know it today—it may once have been blue.

This discovery, as the scientists behind it emphasize, strengthens the case that Mars was not only habitable—but perhaps, for a time, was a place that looked strikingly familiar.

Reference:

Li, J., Liu, H., Meng, X., Fang, G. (2025). Ancient ocean coastal deposits imaged on Mars. Proceedings of the National Academy of Sciences, 122(9), e2422213122. https://doi.org/10.1073/pnas.2422213122