NASA finds evidence of multiple habitable episodes on Mars in Jezero Crater

NASA's Perseverance rover has found evidence that Jezero Crater on Mars hosted several episodes of liquid water, creating conditions that could have supported life. Researchers identified about two dozen minerals that reveal a dynamic history of volcanic rocks altered by contact with water, indicating habitability may have existed at more than one time in Jezero's past. The discovery adds to the rover's long-running work in the Jezero region, where it has already shown the crater once hosted an ancient lake and a river delta.

The minerals appear to fall into three distinct episodes of fluid activity. The first group comprises greenalite, hisingerite, and ferroaluminoceladonite, minerals that formed in hot, acidic water confined to the crater floor. Greenalite is an iron-rich mineral that forms in high-temperature, low-pH environments; hisingerite is a clay-like mineral created when volcanic rocks react with acidic water; ferroaluminoceladonite forms in volcanic rocks exposed to hot, acidic fluids. The researchers noted that these hot, acidic conditions would have been the most challenging for life, though not necessarily prohibitive. The Perseverance team stressed that finding such harsh conditions does not rule out habitability, noting that life on Earth persists in extreme environments such as acidic pools in Yellowstone.

The second mineral group formed in moderate, near-neutral water and covers a larger area of the crater. Minnesotaite, a clay-like mineral, appeared on both the crater floor and the upper fan region, while clinoptilolite, a zeolite mineral, showed up on the crater floor. The third group formed under low-temperature, alkaline conditions and was widely distributed across explored areas, with sepiolite—an alteration mineral common on Earth—indicating a broad episode of liquid water creating sediments across Jezero Crater. Moreland emphasized that these three phases reveal a passing of the environment from harsher to more hospitable conditions over time, describing the sequence as a progression toward ever-friendlier settings for potential life.

To interpret the rover's mineral data, the team used the Mineral Identification by Stoichiometry (MIST) algorithm in conjunction with the Planetary Instrument for X-ray Lithochemistry (PIXL) data. MIST identifies minerals by comparing measurements to a database of known minerals, and the researchers ran repeated simulations to account for uncertainties in Mars samples that cannot be prepared or scanned with the same precision as Earth rocks. Moreland explained that the statistical approach allows scientists to assign confidence levels to every mineral match, strengthening the study's conclusions. She noted that MIST not only informs Mars 2020 science and decision-making but also creates a mineralogical archive of Jezero Crater that will be invaluable if samples are returned to Earth.

The findings reinforce the view that Jezero was not a single, static environment but a dynamic landscape with episodic water activity that could have provided habitable conditions at multiple points in Mars’ history. The minerals help map a timeline of environmental shifts that, taken together, suggest Mars hosted environments potentially conducive to life more than once. Each new mineral discovery informs scientists where to focus sample collection and how to interpret past habitability, guiding Perseverance as it selects rocks for possible future return to Earth. The research also aligns with earlier rover-derived evidence of an ancient lake and delta in Jezero and underscores the importance of continued mineralogical analyses to understand Mars’ paleoclimate and its capacity to sustain life. The work serves as a bridge to future sample return missions, offering a richer mineralogical archive that could help interpret Martian samples once they reach laboratories on Earth.