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<\/div>Topographical map of Mars showing Utopia Planitia, which may once have been an ocean<\/p>\n
U.S. Geological Survey<\/p>\n<\/div>\n<\/figcaption><\/figure>\n<\/p>\n
A possible ancient shoreline has been found in the region of Mars explored by the Chinese rover Zhurong, providing further evidence that an ocean may once have covered a vast area of the lowlands in the planet\u2019s northern hemisphere.<\/p>\n
The rover landed in southern Utopia Planitia in May 2021 and remained active for almost a year. Researchers studying data from the rover have found hints of an ancient ocean<\/a> or liquid water as recently<\/a> as 400,000 years ago.<\/p>\n Now, Bo Wu<\/a> at Hong Kong Polytechnic University and his colleagues have conducted a comprehensive analysis of the topographic features in the landing area, combining remote sensing data from satellites with observations from the rover.<\/p>\n They say they have found features consistent with the existence of a shoreline in southern Utopia, including troughs and sediment channels. They also dated and identified the composition of surface deposits in the area. Based on this, the team thinks the ocean existed 3.68 billion years ago, but froze and then disappeared around 260 million years later.<\/p>\n \u201cThe findings not only provide further evidence to support the theory of a Martian ocean but also present, for the first time, a discussion on its probable evolutionary scenario,\u201d says Wu.<\/p>\n <\/p>\n The area can be divided into a shallow section to the south and a deep section in the north. Even the shallow part of the ocean may have been up to 600 metres deep, says Wu, but there isn\u2019t enough data to estimate the maximum depth of the ocean.<\/p>\n \u201cWater is a key ingredient for life, and the past presence of an ocean on Mars raises the prospect that Mars once might have been capable of harbouring microbial life at its early stage,\u201d he says.<\/p>\n