Water on Mars: Map by the ESA reveals all the locations

It took a decade to develop the map.
Loukia Papadopoulos
ESA Mars water map
ESA Mars water map


A new map created over the last decade using data from ESA’s Mars Express Observatoire pour la Mineralogie, l’Eau, les Glaces et l’Activité (OMEGA) instrument and NASA’s Mars Reconnaissance Orbiter Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) instrument shows water-related mineral deposits across the planet, according to a press release by ESA.

In particular, it shows the locations and abundances of aqueous minerals. What took the scientists by surprise was the impressive abundance of these minerals. Ten years ago, planetary scientists knew of around 1000 such locations, making them geological oddities. The new map, however, has revealed hundreds of thousands of such areas in the oldest parts of the planet.

“This work has now established that when you are studying the ancient terrains in detail, not seeing these minerals is actually the oddity,” said in the statement John Carter, Institut d’Astrophysique Spatiale (IAS) and Laboratoire d’Astrophysique de Marseille (LAM), Université Paris-Saclay and Aix Marseille Université, France.

Water influenced the planet's geology

Scientists have deduced that water played a huge role in shaping geology around the Red Planet. The big question is whether the water was always there or showed up for shorter, more intense periods. While not yet providing a definitive answer, the new results certainly give researchers a better tool for finding the answer.

“I think we have collectively oversimplified Mars,” said Carter. So far, planetary scientists have tended to think that only a few types of clay minerals on Mars were created during its wet period, which is far from the truth the map reveals.

While it’s possible that many of the Martian salts did form later than the clays, the map shows many exceptions where there is intimate mixing of salts and clays and some salts that are presumed to be older than some clays.

Water on Mars: Map by the ESA reveals all the locations
A global map of hydrated minerals on Mars.


A slow evolution

“The evolution from lots of water to no water is not as clear cut as we thought; the water didn’t just stop overnight. We see a huge diversity of geological contexts so that no one process or simple timeline can explain the evolution of the mineralogy of Mars. That’s the first result of our study. The second is that if you exclude life processes on Earth, Mars exhibits a diversity of mineralogy in geological settings just as Earth does,” Carter adds.

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The results are presented in a pair of papers written by Carter, Lucie Riu, and colleagues. Riu even decided to quantify the amounts of the minerals that were present. “If we know where and in which percentage each mineral is present, it gives us a better idea of how those minerals could have been formed,” she says.

Riu was at the Institute of Space and Astronautical Science (ISAS), Japanese Aerospace Exploration Agency (JAXA), Sagamihara, Japan, when part of the work was performed but is now an ESA Research Fellow at ESA’s European Space Astronomy Centre (ESAC) in Madrid.

The project is reminiscent of a similar map of the planet released in 2019. Now that we have a clearer image of the composition of this precious planet, we could use it to inform future space exploration missions. What does the future hold for Mars? Only time will tell.

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