NASA’s Perseverance rover has made groundbreaking discoveries on Mars, revealing that the Jezero Crater once experienced several distinct phases of water activity. This new evidence suggests that Mars may have harbored environments suitable for life at various points in its ancient history. Through advanced mineral analysis, scientists have uncovered a story of shifting water conditions that could have supported microbial life. This study, published in the Journal of Geophysical Research: Planets, sheds light on the dynamic and evolving conditions that once existed on the Red Planet.
The Evolving Chemistry of Jezero Crater
In its ongoing mission to explore Mars, Perseverance has provided invaluable data about the planet’s past, particularly in the Jezero Crater. Scientists used a cutting-edge analysis technique known as the Mineral Identification by Stoichiometry (MIST) algorithm to study mineral deposits in the crater. This innovative method, which utilizes X-ray data from Perseverance’s Planetary Instrument for X-ray Lithochemistry (PIXL), allowed researchers to identify 24 different minerals that tell the story of Mars’ evolving chemistry.
According to Eleanor Moreland, a graduate student at Rice University and lead author of the study, “The minerals we find in Jezero using MIST support multiple, temporally distinct episodes of fluid alteration,” suggesting that the location hosted various environments with liquid water over time. Each of these water episodes likely had distinct chemical compositions and temperatures, affecting how the minerals formed. This discovery reinforces the idea that Jezero Crater was not merely a one-time site of water activity but instead experienced several dynamic phases conducive to potential habitability.
The findings were published in the Journal of Geophysical Research: Planets, furthering our understanding of Mars’ geochemical history. Moreland’s team emphasizes that the shifting mineralogy of Jezero over time represents a “shift from harsher, hot, acidic fluids to more neutral and alkaline ones,” conditions that increasingly became favorable for life. This progression of conditions underscores the potential for life on Mars, especially during the later stages of the planet’s history.
Acidic Beginnings: The Harsh Early Phase
The first phase of water activity on Mars, as revealed by Perseverance’s data, involved extremely harsh conditions. Early water in Jezero Crater was highly acidic and hot—far from the conditions that could support life as we know it. During this period, minerals such as greenalite and hisingerite formed, signaling a time when volcanic rocks were intensely altered by high-temperature, acidic fluids. This phase represents some of the oldest materials discovered in the study.
Co-author Kirsten Siebach, an assistant professor of Earth, Environmental, and Planetary Sciences at Rice University, notes,
“These hot, acidic conditions would be the most challenging for life.” While these extreme environments might seem inhospitable, Earth offers examples of organisms that thrive in similarly harsh conditions. “On Earth, life can persist even in extreme environments like the acidic pools of water at Yellowstone,” Siebach added, highlighting that while these conditions would challenge life, they do not entirely rule out its possibility.
Neutral Waters: A Shift Toward Habitability
As time progressed, the water in Jezero Crater became less harsh, transitioning to more neutral conditions that would have been more favorable for microbial life. During this phase, minerals like minnesotaite and clinoptilolite began to form, signaling a cooling and chemical shift in the water’s composition. These minerals are typically associated with environments that could support life, as neutral pH levels are much more conducive to biological processes than the acidic conditions that preceded them.
The presence of these minerals marks a significant shift in the crater’s environmental conditions, suggesting that Jezero Crater may have hosted relatively life-friendly environments for extended periods. This phase provides hope that life could have taken hold on Mars when conditions were more temperate and neutral.
Alkaline Waters: The Most Life-Friendly Phase
The final phase of water activity at Jezero Crater was the most promising for life. The water during this period was cooler and alkaline, much more similar to Earth’s habitable environments. This transition is particularly significant because alkaline conditions are generally considered highly supportive of life. The widespread formation of sepiolite, a mineral found in alkaline environments on Earth, points to the most extensive water presence on Mars during Perseverance’s exploration.
“The 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.
The widespread presence of these life-friendly minerals suggests that, during this phase, Mars may have hosted conditions that were ripe for microbial life to thrive.