Mars as seen by the Zhurong rover
Mars seems to have had liquid water on its floor as not too long ago as 400,000 years ago, probably beginning as snow that melted and helped flip sand dunes into strong, cracked crusts, based on photographs taken by China’s Zhurong rover.
A number of proof factors in the direction of Mars having had huge deposits of liquid water sooner or later in its historical previous, however how lengthy this water endured for or how a lot made it to the planet’s latest previous is unclear.
Now, Xiaoguang Qin on the Chinese Academy of Sciences in Beijing and his colleagues have discovered cracks, crusts and clumps of particles on prime of sand dunes within the Martian plain of Utopia Planitia that may solely be defined by liquid water from between 400,000 and 1.4 million years ago.
“Sand dunes are a more modern landform,” says Qin. “These crusts on the dunes’ surfaces have solidified the sand dunes and stopped them moving.”
The presence of sure salts within the sand led the workforce to imagine the water initially fell onto the sand dunes within the type of snow or frost, which later melted and blended with the sand to kind hydrated minerals. These minerals then clumped collectively and, as soon as the water evaporated, have been cemented in place and shaped the cracked crust seen by the rover’s digicam.
The mechanism that Qin and his workforce suggest for the cracks having shaped by a water-based cement is convincing, says Matt Balme on the Open University within the UK, however there may be nonetheless a chance that it might have shaped via one other Martian geological mechanism that we aren’t conscious of on Earth, he says.
Given what number of sand dunes have been seen in different Mars missions, it may be value revisiting these photographs to see if comparable options will be discovered, says Balme.
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