Today, Mars is a vast, cold desert. The images that we have captured over the years with different missions, such as NASA’s Curiosity and CNSA’s Tianwen-1, to mention the most recent, have allowed us to observe the peculiar Martian landscape, characterized by reddish-orange dunes, craters and volcanoes.
We’ve also seen huge deltas and riverbanks that suggest water once flowed over the planet’s surface, but they’re not the only thing we have to support this hypothesis. ESA’s Mars Express spacecraft and NASA’s Mars Reconnaissance Orbiter have made a great contribution with their instruments.
Thanks to the visible and infrared mineralogical mapping spectrometer (OMEGA) of the European probe and the visible and near-infrared spectrometer (CRISM) of the American probe, we have managed to detect watery mineral deposits throughout the planet and create a detailed map with all of them, explains the ESA.
New evidence that there was water on Mars
But why is this finding important? Aqueous minerals, experts believe, come from rocks that have been chemically transformed by the action of water in the past, but that today appear as clays and salts, which can help us understand the geological evolution of mineralogy on Mars.
on our planet, clays form when water interacts with rocks, being the amount a determining factor for the type of clay. Smectite and vermiculite, for example, are formed with low amounts of water, which means that they retain most of their original chemical elements (iron and magnesium).
As you might imagine, when there is a greater amount of water, other types of clay are formed, which tend to detach from the original properties of the original rocks. In this case, the soluble elements tend to be carried away and we can observe aluminum-rich clays such as kaolin.
Researchers from both space agencies have been in for a big surprise. Some of these minerals are present on Mars, and in generous amounts.. A decade ago we believed that there were around 1,000 outcrops, but with the new map we have identified “hundreds of thousands” in many places.
As more study of the red planet, experts discover new features of its history. If the presence of aqueous minerals was scarce, it was to be assumed that the presence of water would have been limited in extent. Now, on the contrary, it is believed that “it played a very important role in the past of the planet”.
“The evolution from a lot of water to no water is not as clear as we thought, the water did not stop flowing overnight. We see a great diversity of geological settings, so no simple process or timeline can explain the evolution of Mars mineralogy,” says John Carter of the Institut d’Astrophysique Spatiale (IAS) and Laboratoire d’Astrophysique de Marseille ( LAM), Université Paris-Saclay and Aix Marseille Université, France.
The new water map of Mars
In the map that we find above in this article we observe the mineral deposits found by the two space missions. Mostly it is about Clays include minerals rich in iron and magnesium such as smectite and vermiculite.. In addition, various points of interest and possible landing sites for future manned missions are included.
Mawrth Vallis, an old outflow channel that is rich in clay, is one of them. Oxia Planum, another clay-rich region, has been selected as a landing site for ESA’s Rosalind Franklin rover. Meridiani Planum, meanwhile, straddles the Martian equator and was the landing site for NASA’s Mars Exploration Rover Opportunity.
Valles Marineris is one of the largest canyons in the Solar System. Gale Crater and Jezero Crater were the landing sites for NASA’s Curiosity and Perseverance rovers respectively, the latter of which has also been flown over by the small Ingenuity helicopter. But how did they make this map? Two instruments played a fundamental role.
CRISM provided high resolution spectral images of the surface (up to 15 m/pixel) for very localized areas. OMEGA, for its part, carried out a complete mapping of Mars with spectral resolution with a better signal-to-noise ratio for detecting minerals. In addition, the researchers quantified and classified the data to create the current maps.
Details of the investigation can be found in an article published in the journal Icarus, but the researchers’ work continues. Now that we know which are the richest areas of aqueous minerals on Mars, we can establish more precise landing sites for scientific studieseither with robotic equipment or in future manned missions, although for the latter we will first have to return to the Moon, and an important step is the launch of Artemis I.
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George is Digismak’s reported cum editor with 13 years of experience in Journalism