New research shows Mars’ Jezero crater was repeatedly habitable

• Jezero crater was once a lake billions of years ago. And it’s where the Perseverance rover landed in 2021. Was this area habitable?
• The crater experienced multiple periods of habitability over time, new research shows.
• Water in the crater shifted from acidic and hot early on, to cool and easily habitable later on.

Jezero crater was habitable multiple times

Earlier this month, NASA provided an update on the possible discovery of a biosignature by the Perseverance rover in Jezero crater. Now, another team of scientists has said the crater – which used to be a lake billions of years ago – experienced multiple periods of habitability. Water was more abundant during those periods of time. Eleanor Moreland at Rice University in Houston, Texas, led the new study. The researchers said on September 17, 2025, that Perseverance found two dozen types of minerals showing water altered volcanic rocks in the region. The evidence reveals three distinct periods of habitability. They shifted from least (but still potentially) habitable to the most habitable over time.

The findings support previous data from Perseverance revealing how this former landscape was once habitable by earthly standards.

The researchers published their peer-reviewed results in the journal JGR Planets on September 11, 2025.

New Mars research reveals multiple episodes of habitability in Jezero Crater?? news.rice.edu/news/2025/ne…?? doi.org/10.1029/2024…#Mars ? #PlanetSci

— Daniel Pomarède (@pomarede.bsky.social) 2025-09-22T15:36:39.387Z

Minerals provide clues

So, how did Perseverance determine multiple periods of habitability in Jezero crater? The rover found two dozen types of minerals that provided the clues. The minerals are in volcanic rocks that water had altered in the distant past.

Perseverance used its Planetary Instrument for X-ray Lithochemistry (PIXL) instrument for the analysis. PIXL bombards Martian rocks with X-rays to reveal their chemical composition. These are the most detailed geochemical measurements ever collected on another planet, the study authors said. Moreland explained:

The minerals we find in Jezero using MIST (Mineral Identification by Stoichiometry) support multiple, temporally distinct episodes of fluid alteration, 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.

3 types of water alteration in Jezero crater

The analysis of the minerals revealed three different types of alteration by water.

The first involved localized high-temperature acidic fluids, with the minerals greenalite, hisingerite and ferroaluminoceladonite. These rocks, from the crater floor, were the oldest they studied. This water was very hot and acidic, making it the least habitable for microbes to exist in, although not impossible. Co-author Kirsten Siebach at Rice University said:

These hot, acidic conditions would be the most challenging for life. 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.

Secondly, other minerals such as minnesotaite and clinoptilolite come from a period of water activity that was less acidic, with neutral pH, and cooler. Interestingly, the rover found minnesotaite in both the crater floor and the upper delta fan region, but clinoptilolite was only on the crater floor.

The third period of water alteration was the most habitable. The water was low temperature and alkaline (having a pH of more than 7). Perseverance found the mineral sepiolite all over the region it has explored so far. Its widespread presence shows that habitable conditions were also widespread at the time. Overall, the different minerals show how conditions changed from barely habitable to increasingly habitable over time. As Moreland said:

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.

Using error analysis to study minerals

Perseverance’s onboard lab is powerful, but it still has limitations compared to labs on Earth. To help make the analysis as thorough as possible, the researchers used a statistical approach, repeatedly testing mineral identifications while considering the potential errors. This is similar to how meteorologists forecast hurricane tracks, by running many models and comparing them. Moreland said:

Our error analysis lets us assign confidence levels to every mineral match. 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.

The approach paid off, revealing the complex water history of Jezero crater. And, combined with other results including the discovery of possible biosignatures in the crater, the results add further support to the idea that just maybe, Mars really was once home to microbial life.

Bottom line: New research shows that Mars’ Jezero crater, which was once home to a lake, was repeatedly habitable in the past.

Source: Multiple Episodes of Fluid Alteration in Jezero Crater Indicated by MIST Mineral Identifications in PIXL XRF Data From the First 1100 Sols of the Mars 2020 Mission

Via Rice University

Read more: NASA announces Mars rock as a potential biosignature

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