The thick layers of clay found on the Red Planet, reaching hundreds of meters in depth, clearly indicate the presence of water in the past — a key condition for life. But where and how exactly did they form? A new study by a team from the University of Texas at Austin, published in Nature Astronomy, provides clear answers and reveals fascinating details about ancient Mars.
Cradle for life
By analyzing data from 150 clay deposits identified by NASA’s Mars Reconnaissance Orbiter, researchers have discovered a clear pattern. Most clays are concentrated at low elevations near ancient lake deposits, but far from dense networks of valleys. This indicates that they formed near stable standing water bodies billions of years ago.
These areas were well-watered, but the terrain was flat. These conditions ensured long-term stability,” explains lead author Rhianna Moore, who is currently working on NASA’s Artemis mission.
A stable aquatic environment was crucial: it made it possible to create thick, mineral-rich clay layers. Such calm, water-rich, and mineral-rich conditions are considered ideal for the emergence and maintenance of life.
The Martian difference and the carbon mystery
However, the clay on Mars also reveals fundamental differences from Earth. On our planet, the movement of tectonic plates constantly supplies fresh rock for reactions with atmospheric CO2 and water, helping to regulate the climate. Mars, however, lacked tectonic activity.
Researchers suggest that when Martian volcanoes emitted CO2, the lack of a mechanism for supplying new reactive rock led to the accumulation of greenhouse gases. This could have made the planet warmer and wetter, promoting the formation of clay, but at the same time caused a global imbalance in the water-carbon cycle.
Unraveling the carbonate mystery
This imbalance may explain one of the greatest mysteries of Mars: why are there almost no carbonate rocks such as limestone, which should have formed in the presence of water, CO2, and the planet’s basic volcanic rocks? The study offers an answer: intensive clay formation could have “blocked” the water and chemical components necessary for carbonate formation.
Thus, thick clay layers are not only time capsules of Mars’ wet past with the potential for life, but also the key to understanding the planet’s unique geochemical evolution and unraveling its carbonate mystery. They paint a picture of a world radically different from Earth, but still conducive to the formation of complex mineral structures.
We previously reported on how Mars’ atmosphere became trapped inside rocks.
According to Phys
