'300-million-year-old ocean': China's Zhurong rover discovers evidence of ancient coastline on Mars

Produced by: Tarun Mishra

New Clues to Martian Ocean

China's Zhurong rover, which landed on Mars in 2021, has found new geological evidence suggesting that Mars might have once hosted a vast ocean. The study, published in Nature, strengthens the theory that an ocean may have covered nearly a third of the Red Planet billions of years ago.

Focus Area - Utopia Region

The rover explored the Utopia Planitia, a northern Martian plain where previous indications of ancient water had been identified. The study's findings come from the detailed examination of this area, adding significant insights to the ocean hypothesis.

Observed Land Features

The Zhurong mission detected geological features associated with past water, including “pitted cones, polygonal troughs, and etched flows,” which align with structures often found in water-rich or icy environments.

Signs of an Ancient Shoreline

Based on data collected from Zhurong and satellite imaging, researchers suggested that the region could have once been a shoreline, providing additional support for the existence of a large ocean in Mars’s past.

Formation Timeline

The study proposes that the ocean was likely formed due to a massive flooding event around 3.7 billion years ago. Later, the water froze and carved out a coastline before eventually disappearing approximately 3.4 billion years ago.

Ongoing Debate Among Scientists

Some experts remain cautious about the findings. Benjamin Cardenas, a Mars researcher from Pennsylvania State University, expressed scepticism, suggesting that the study might not fully account for Mars’s strong winds that could have eroded the shoreline evidence over billions of years.

Impact of Erosion and Meteors

While acknowledging that wind erosion might have altered some rocks, study lead Bo Wu highlighted the role of meteors, which occasionally expose buried rock and sediment, providing researchers with further evidence of past environments.

Significance for Life Studies

Determining if Mars had an ancient ocean is pivotal for understanding whether it could have once supported life. According to Cardenas, oceanic environments on Earth are seen as prime sites for the origin of life, suggesting Mars might have once offered similar conditions suitable for life.