There is a lake on Mars with minerals formed with the help of oxygen
The Curiosity rover studied the rocks of an ancient, long-dry lake on Mars and found that billions of years ago there were conditions suitable for life. In the rocks of Gale Crater, Curiosity found a surprising amount of manganese oxide, a mineral that is commonly found in lakes on Earth due to the high degree of oxidation in them, which leads to the formation of manganese crystals in the presence of oxygen.
Discovery of oxide on Mars manganese in such large quantities suggests that similar conditions persisted in Gale Crater when it was filled with water in ancient times.
“On Earth, these deposits form all the time because of the high oxygen content in our atmosphere produced by photosynthetic life and microbes that help catalyze manganese oxidation reactions,” explains geochemist Patrick Gasda of Los Alamos National Laboratory.
There is no evidence of life on Mars, and the mechanism of oxygen formation in the ancient atmosphere of the planet is unclear, so how manganese oxide was formed and concentrated here really puzzles experts.
Let us be clear: manganese oxide is widespread on Earth and in participates in abundance in biological processes. It is an essential mineral for a number of biological processes in the human body, but virtually all life on Earth requires manganese for one reason or another.
Patrick Gasda and his colleagues took a closer look at manganese using Curiosity's ChemCam, which uses a laser to vaporize the minerals and then analyzes the light to determine their composition. The researchers then examined different mechanisms of manganese deposition in Gale Crater lake: deposition from lake water or from groundwater through porous sands.
The scientists concluded that the most likely scenario would be the deposition of manganese oxides along the lakeshore in an oxygen-rich atmosphere. They say this is further evidence of an ancient and habitable lacustrine environment in the ancient Gale Crater on Mars, as manganese oxide can take thousands of years to form, depending on oxygen levels.
Where did this oxygen come from — Another question that remains unanswered, although it is possible that meteorite impacts early in Mars' history could have released oxygen from surface icy deposits.
The findings offer tantalizing prospects for searching for traces of ancient life on Krasnaya planet. Oxidation caused by microbes could leave biosignals and organic matter in manganese-bearing rocks. Researchers say Perseverance, which is currently studying the planet's environment, could find them on its travels.
“Lake Gale gives us a glimpse into a habitable environment that is remarkably similar to modern places on Earth, says planetary scientist Nina Lanza. “Manganese minerals are often found in shallow, oxygenated waters on the shores of lakes on Earth, and it is surprising that such recognizable features could be found on ancient Mars.”
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