Chinese scientists have uncovered direct evidence suggesting the existence of an ancient ocean on Mars. Working alongside international researchers, they identified subsurface features indicative of a former shoreline on the Red Planet, according to a recent study published in the journal PNAS.
The findings were made possible by data collected from China’s Mars rover, Zhurong, which successfully landed in southern Utopia Planitia in May 2021. By May 2022, Zhurong had traversed 1,921 meters, gathering extensive scientific data along the way.
Equipped with a dual-frequency subsurface-penetrating radar, Zhurong probed beneath the Martian surface to detect hidden structures and potential water ice deposits. The radar data revealed extensive dipping reflectors in the subsurface of southern Utopia Planitia. These structures resemble coastal sedimentary formations found on Earth.
“The reflectors dipped unidirectionally with inclinations ranging from six to 20 degrees,” the researchers noted. “They were imaged to a thickness of 10 to 35 meters along an uninterrupted 1.3-kilometer northward traverse perpendicular to the shoreline.”
The consistency and physical properties of these features ruled out other possible origins, such as sand dunes or river deposits. Instead, the data supports the presence of a significant onshore sediment supply into a large body of water, rather than a short-lived melt event.
For years, scientists have debated the existence of ancient oceans on Mars. While orbital images have suggested that the northern lowlands may have been covered by an ocean spanning a third of the Martian surface, inconsistent elevation data and geological transformations over billions of years have made it challenging to confirm this hypothesis.
This new subsurface evidence strengthens the case for an ancient ocean in Mars’s northern plains and offers crucial insights into the planet’s environmental history. Understanding Mars’s past water presence is key to unraveling the mysteries of its potential for life and guiding future exploration missions.
The international research team included scientists from Guangzhou University, the Chinese Academy of Sciences, Tongji University, the University of California, Berkeley, and Pennsylvania State University.
