Chinese Rover Discovers Evidence of Vast Ocean on Mars 3.5 Billion Years Ago

New findings suggest that a vast ocean may have covered parts of Mars nearly 3.5 billion years ago. China’s Zhurong rover recently discovered signs of an ancient coastline in the southern Utopia region, which likely belonged to a short-lived sea from Mars’ early history.

The research, published in *Scientific Reports*, details how the Zhurong rover found evidence in the Vastitas Borealis plain in the northern hemisphere, an area thought to have once held an ocean. The discovery of fine-grained minerals, including hydrated silica, suggests a former coastline rather than volcanic origins.

Lead researcher Bo Wu from The Hong Kong Polytechnic University noted that features such as “pitted cones, polygonal troughs, and etched flows” indicate the presence of an ancient sea near the rover’s landing area. Previous studies suggest these pitted cones may have resulted from mud volcanoes in regions with past water or ice.

Data from Zhurong, satellite observations, and Earth-based analysis point to a probable shoreline in this region. Scientists estimate that this ocean was created around 3.7 billion years ago by a massive flood event. The geological formations—such as troughs and channels—observed in Utopia Planitia hint at a nearshore environment, leading researchers to believe these deposits were left by a significant flooding event approximately 3.68 billion years ago.

“We conducted an extensive geomorphological study of the landing site, using remote sensing along with on-site observations, revealing features that align with a nearshore zone in southern Utopia,” the researchers explained.

However, scientists caution that while the data hints strongly at a former ocean, it does not offer direct proof of such a body of water on Mars.