Topographic map of Mars showing Utopia Planitia, which may once have been an ocean
United States Geological Survey
A possible ancient coastline has been discovered in the region of Mars explored by China’s Zhurong rover, providing further evidence that an ocean may have once covered a large area of the planet’s northern hemisphere lowlands.
The rover landed in southern Utopia Planitia in May 2021 and remained active for almost a year. Researchers studying data from the rover found evidence of a ancient ocean or liquid water like recently like 400,000 years ago.
NOW, Bo Wu from the Hong Kong Polytechnic University and colleagues conducted a comprehensive analysis of the topographical features of the landing zone, combining remote sensing data from satellites with observations from the rover.
They say they found features consistent with the existence of a coastline in southern Utopia, including troughs and sediment channels. They also dated and identified the composition of surface deposits in the region. Based on this, the team believes the ocean existed 3.68 billion years ago, but froze and then disappeared about 260 million years later.
“The results not only provide additional evidence to support the theory of a Martian ocean, but also present, for the first time, a discussion of its likely evolutionary scenario,” says Wu.
The area can be divided into a shallow section to the south and a deep section to the north. Even the shallow part of the ocean could be as deep as 600 meters, Wu said, but there is not enough data to estimate the ocean’s maximum depth.
“Water is a key ingredient of life, and the past presence of an ocean on Mars suggests that Mars may once have been capable of supporting microbial life in its early stages,” he says.
Mathieu Laposte from Stanford University in California, says the question of whether oceans existed on early Mars is a highly controversial question and one that has crucial implications for the planet’s past habitability. He says future missions will need to test the results of this new research.
“Utopia Planitia could provide an invaluable record of the coastal and coastal environments of early Mars,” says Lposte.
