Mars’ ancient waterways could reveal secrets of the planet’s past
The European Space Agency’s Mars Express spacecraft has captured impressive images of Holden Basin on Mars, which is part of a key area for the ongoing search for life on the Red Planet. The images and further investigation of the area could help reveal how water once flowed over the Martian surface.
The close-up image of Holden Basin, captured on April 24, 2022, by Mars-ExpressThe High Resolution Stereo Camera (HRSC) shows the geological features of the ancient water reservoir near the nearly 95 mile wide (150 kilometer) Holden Crater.
The Holden Basin is one of the series of channels and sinkholes that make up the Uzboi-Ladon-Morava (ULM) flow system on the southern hemisphere of March. This system has become a major target for Mars orbiters such as Mars Express, as scientists believe it may have once drained up to 9% of the Red Planet’s water.
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Before Mars has lost its water about 4 billion years ago, possibly due to the Martian atmosphere being stripped by violent solar radiation that allowed water vapor to “leak” into space, liquid water would have flowed through channels that drain into the Argyre Planitia.
From this 1,100 mile wide (1,770 km) plain which descends up to 3.2 miles (5.2 km), the water would have flowed through the valley called “Uzboi Vallis” beyond the area now marked by the Holden crater – which was created later in the planet’s history.
The water would then have accumulated in Holden Basin before flowing through Ladon Valles – an ancient river valley system leading to the 274-mile (440 km) wide Ladon Basin.
The new image reveals a distinct crater to the south of the basin and the basin walls gently dip to a depth of about 5,000 feet (about 1,500 meters) below the surrounding Martian surface.
The northeast side of Holden Basin, meanwhile, shows where water would have flowed from this reservoir into the Ladon Valles. Scars and rugged terrain are visible in the image, likely created by melting water ice below the Martian surface.
Where there is water there is a chance of life
The European Space Agency (ESA) said in a report (opens in a new tab) this experience with our own planet shows that water and life go hand in hand. Scientists are eager to find out if the same could be true for Mars billions of years ago.
The soils of Ladon Valles and Holden Basin contain phyllosilicate, a type of mineral that includes clays created by the interaction of rock and water that have been linked to the origins of life on Earth. The phyllosilicates of these regions are present in stratified deposits that could have served as a reaction center for organic molecules, the building blocks of terrestrial life. It is for this reason that scientists are so interested in the region.
Holden Crater probably formed as a result of an ancient asteroid strike when material ejected by the impact fell back to the planet’s surface and filled the ancient Holden Basin, which had formed by an earlier impact in the planet’s history.
Since Holden Crater shows no evidence of water passing through it in the past, scientists believe it must have formed after the ULM system dried up.
Due to its geological significance and potential to harbor evidence of ancient life, Holden Crater was shortlisted as the landing site for the Curiosity and Perseverance rovers, but lost to wind crater and Jezero Crater respectively.
Mars Express, which has imaged the Martian surface and atmosphere from orbit since 2003, now ensures the area is well studied.
Previous images of Holden Basin have revealed ridges and grooves carved by Martian winds, impact craters and ancient rivers, as well as fossilized lava pools and volcanoes.
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