Mars' Jezero Crater had several different 'water periods' that could have supported life

Mars is dry today, but minerals formed in the past tell another story. New research using NASA’s Perseverance rover shows that Jezero Crater experienced more than one watery episode.

Each left behind minerals that record changing conditions, from acidic to alkaline, with some environments friendlier to life than others.

The work goes beyond saying “water was here.” It reveals the chemical character of that water and when it altered volcanic rocks. That history matters because it shapes the search for ancient life on Mars.

Perseverance and MIST analysis

The study was led by Eleanor Moreland, a graduate student at Rice University. She used the Mineral Identification by Stoichiometry (MIST) algorithm, designed at Rice, to interpret chemical scans from Perseverance’s Planetary Instrument for X-ray Lithochemistry (PIXL).

PIXL blasts Martian rocks with X-rays and measures how elements scatter back. The result is a detailed chemical fingerprint.

“The minerals we find in Jezero using MIST support multiple, temporally distinct episodes of fluid alteration,” Moreland said.

“Which indicates there were several times in Mars’ history when these particular volcanic rocks interacted with liquid water and therefore more than one time when this location hosted environments potentially suitable for life.”

Mars minerals show life

Minerals form under specific conditions of temperature, pH, and fluid chemistry. That makes them natural storytellers.

By identifying 24 mineral species in Jezero, the team pieced together a sequence of three water-related events.

The first group shows evidence of hot, acidic fluids. These include greenalite, hisingerite, and ferroaluminoceladonite, all confined to crater floor rocks. Such conditions are considered harsh for biology.

“These hot, acidic conditions would be the most challenging for life,” said co-author Kirsten Siebach, assistant professor at Rice.

“But on Earth, life can persist even in extreme environments like the acidic pools of water at Yellowstone, so it doesn’t rule out habitability.”

Neutral waters arrive

The next chapter involves fluids closer to neutral in pH. Minerals like minnesotaite and clinoptilolite formed under cooler, more balanced conditions.

Minnesotaite shows up in both the crater floor and the fan deposits, while clinoptilolite is only in the floor.

This shift points to a time when water influenced more parts of the crater, creating zones that looked far more favorable to life.

Mars minerals support life

The third mineral group is the most promising. It reflects low-temperature, alkaline fluids.

Sepiolite, common on Earth and often linked with life-friendly conditions, appears across every region sampled by Perseverance.

“These minerals tell us that Jezero experienced a shift from harsher, hot, acidic fluids to more neutral and alkaline ones over time – conditions we think of as increasingly supportive of life,” Moreland said.

Confidence in the results

Studying Martian samples is tricky. Unlike on Earth, scientists cannot cut, polish, or test these rocks in labs. To overcome that, the team created a statistical model that checked and re-checked mineral identifications.

“Our error analysis lets us assign confidence levels to every mineral match,” Moreland explained.

“MIST not only informs Mars 2020 science and decision-making, but it is also creating a mineralogical archive of Jezero Crater that will be invaluable if samples are returned to Earth.”

This approach is similar to running multiple weather models before predicting a storm track. It does not settle for one answer but gives a range of likely outcomes, making the catalog more trustworthy.

Finding signs of past life

Jezero Crater once held a lake, which is why Perseverance landed there. These new results confirm that its waters came and went in phases.

Some phases were harsh, others more welcoming. That complexity increases the chances that Perseverance is drilling in the right places to find signs of past life.

The mineral catalog also frames discoveries like the possible biosignature reported at Sapphire Canyon.

While this study did not cover that site, it shows that similar habitable conditions extended across Jezero Crater. This strengthens the context for interpreting such finds.

Future research on Mars minerals

Perseverance’s mission is still unfolding. Each drilled core, and each PIXL scan, adds to a growing archive of Mars’ past. That archive will gain even more value when samples finally reach Earth.

This project received support from NASA’s Mars 2020 program, JPL, the PIXL team, and the Mars Exploration Program.

With every new mineral identified, the story of Mars grows less like a single-note record and more like a layered history of change.

The study is published in the Journal of Geophysical Research Planets.

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