NASA’s Curiosity rover uncovers metal‑rich hotspot tied to ancient Martian lake

A team of scientists using the ChemCam instrument on NASA’s Curiosity Mars rover has discovered the highest amounts of iron, manganese, and zinc ever found together in Gale Crater on Mars. Minerals with these metals were found in remarkably well-preserved ripples in rocks, indicating the high likelihood that a shallow lake existed at this location. The findings are published in the Journal of Geophysical Research: Planets.

Metal-rich deposits form in lakes on Earth by chemical reactions called “redox (reduction-oxidation) reactions” in places that are almost always inhabited by microbes. Finding similar environments on Mars is exciting because it means that Gale Crater was home to an ancient lake that had favorable conditions for past life.

“The metals were found in preserved ripples, which is the clearest evidence we have that a lake was present in Gale Crater. But what’s more surprising is that this lake existed high up on Mount Sharp, where the rover explored rocks that were deposited during an era on Mars when the climate was drying out,” said Patrick Gasda, ChemCam Instrument science team member and research scientist at Los Alamos National Laboratory.

“Ancient Mars was much wetter, and lakes in craters were common then. It seems that as Mars became drier and colder, lakes that formed less frequently were very short-lived.”

ChemCam uses a technique called “laser-induced breakdown spectroscopy” to zap rocks to create a plasma and then collects the light from that plasma to understand what elements are present on the planet’s surface. Its goal is to establish past habitability on Mars, addressing the question of whether Mars was once suitable for life.

The ChemCam instrument was built and is operated by a partnership between Los Alamos and the Institut de Recherche en Astrophysique et Planétologie (IRAP). The rover was built and is operated by NASA’s Jet Propulsion Laboratory.

Curiosity has recently been exploring a large sedimentary mound that researchers believe shows the transition from a warm and wet (phyllosilicate-rich) to a cold and drier (sulfate-rich) Mars.

Implications for past life on Mars

The discovery of redox-active metals such as iron and manganese could indicate that life would have thrived in this lake if life existed on Mars. Some forms of microbial life on Earth can use these metals as energy sources. The fact that these metals were found in the Amapari Marker Band suggests that even as Mars dried out, there were still isolated pockets of water where microbial life could have survived.

These iron, manganese, and zinc deposits can lay the groundwork for future research on the red planet. They can help researchers decide where Curiosity should explore next or determine locations for potential sample return missions.

“Given the exciting astrobiological implications raised by the Amapari Marker Band, these types of materials should be prioritized for future Curiosity chemistry analysis or for returning samples from Mars’ Jezero Crater, should the opportunity arise,” Gasda said.