Nickel deposits found on Mars, similar to those formed on Earth by microbes

The American Perseverance rover has discovered unique nickel deposits in the Neretva region of the western Jezero crater on Mars. These deposits are similar in properties and structure to terrestrial rocks formed by microbial activity during the Archean and Paleoproterozoic eras. This makes them another candidate for traces of Martian life, the researchers write in their article in the journal Nature Communications.

"While exploring the Neretva region, the Perseverance rover encountered deposits of iron, sulfur, and organic compounds containing record amounts of nickel for Mars, reaching 1.1% of the total mass of these rocks. Nickel plays an important role in the life of terrestrial life, and its presence alongside sulfur and organics underscores the community's enormous interest in returning these samples to Earth," the researchers write.

This conclusion was reached by the Perseverance rover's science team, led by Morgan Cable, a research scientist at NASA's Jet Propulsion Laboratory (USA), while studying data collected by the rover's 'njuj instruments at two locations in the western part of Jezero Crater in the Neretva region, home to clay and shale deposits formed at the bottom of an ancient Martian lake.

A year ago, scientists discovered unusual sulfide and phosphate deposits in this region of Mars. These deposits formed in an alkaline environment uncharacteristic of Mars, typical of habitats for bacteria and other microorganisms that form layers of similar rocks on Earth. This discovery sparked intense interest in searching for other possible "biosignatures" in the Neretva region using instruments on the Perseverance rover.

Nickel "Traces" of Martian Life

Recently, planetary scientists using the rover's SuperCam instrument discovered not only iron and sulfur but also large amounts of nickel, coexisting with organic deposits and various sedimentary rocks.

This discovery immediately attracted the attention of scientists, as on Earth, similar deposits containing sulfur, iron, nickel, and organic matter were formed by the activity of primitive chemotrophic microbes, which absorbed hydrogen and sulfate ions from the environment and converted them into pyrite and other sulfur-containing minerals. Biologists hypothesize that "LUCA," a microbe and the common ancestor of all life on Earth, possessed a similar ability.

At the same time, scientists do not rule out the possibility that nickel deposits formed on Mars without the participation of living organisms. However, this would have required very specific and frequently changing environmental conditions, evidence of which researchers have not found in this region of Mars. This makes such rock samples particularly interesting for further study on Earth, if the mission to return them, previously canceled by the US Congress, is revived, the scientists concluded.