Patrick Gasda, from the Space Sciences and Applications group at the Los Alamos National Laboratory and lead author of the study that reveals the discovery of manganese – a chemical element, symbol Mn, atomic number 25 and atomic mass 55 u, solid at room temperature – on Mars , states that It is very difficult for the oxide of this chemical element to form on the surface of Mars and that, therefore, the team I didn’t expect to find it in such high concentrations in a coastal deposit.
Patricio Gasda.
As for Mars, we have no evidence that life exists or has existed and the mechanism of oxygen production in the ancient atmosphere of Mars is also unclear, so it’s really intriguing how the manganese oxide formed and concentrated there. These findings point to larger processes occurring in the Martian atmosphere or surface water and show that more work is needed to understand oxidation on the Red Planet.
The discovery process
Developed by Los Álamos and CNES (French space agency), ChemCam uses a laser to vaporize rock surfaces and analyze the resulting plasma to determine its elemental composition.
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The team studied a variety of sediments in the crater, including sands, silts and muds. They observed that sandy sediments, being more porous, allowed groundwater to move through them more easily than the finer silts that dominate lake beds.
They explored how manganese enrichment could occur in these sands, possibly through the movement of groundwater near a lake or delta, and what oxidants could be involved in the precipitation of manganese in these rocks.
On Earth, manganese is usually concentrated in oxygen in the atmosphere, a process that is usually accelerated by microbial activity. Microbes use the different oxidation states of manganese to obtain energy. If Mars ever supported life, the high manganese content in these lakeshore rocks could have been a crucial energy source.
The environment of Lake Gale, as revealed by these ancient rocks, offers us a window into a habitable environment that is strikingly similar to places on Earth today.
News reference:
Gasda P., Lanza N., Meslin P., et al. Manganese-Rich Sandstones as an Indicator of Ancient Oxic Lake Water Conditions in Gale Crater, Mars. JGR Planets (2024).
