New Spectroscopic Evidence of Hydrothermal Activity on Mars Revealed by Perseverance Rover

Mars rover exploring rocky Martian landscape under starry night © SerPak-chronicles-stock.adobe.com

NASA’s Perseverance rover has made a discovery in Jezero Crater, by detecting silica-rich minerals, including well-crystallized quartz and hydrated silica. The findings, published in Earth and Planetary Science Letters by P. Beck, O. Beyssac, E. Dehouck, S. Bernard, M. Pineau, L. Mandon, and colleagues from multiple French institutions, provide the first unambiguous detection of quartz on the Martian surface and suggest past hydrothermal activity that could have implications for ancient life on the Red Planet (1).

A Landmark Discovery in Jezero Crater

Jezero Crater, a site chosen for its geological significance and potential for preserving ancient biosignatures, has been under exploration by Perseverance since February 2021. The rover’s SuperCam instrument, utilizing a combination of laser-induced breakdown spectroscopy (LIBS), infrared (IR), and Raman spectroscopy, identified cobbles made of opaline silica, chalcedony, and quartz. This marks the first time quartz-dominated rocks have been definitively recognized on Mars (1).

The study, led by scientists from the University of Grenoble Alpes, CNRS, Sorbonne Université, and other French institutions, suggests that these silica-rich materials were likely formed through hydrothermal processes. The team proposes that these detections, though found as float rocks, may originate from different depths and temperature conditions within a common hydrothermal system, possibly linked to the Jezero crater-forming impact (1).

Spectroscopic Analysis Confirms Silica-Rich Deposits

Using the SuperCam instrument, researchers analyzed six silica-rich rock samples, identifying distinct mineral phases. LIBS-derived elemental chemistry revealed high silicon content, with some samples appearing nearly pure silica. Infrared reflectance spectra indicated hydrated silica, distinguished by characteristic absorption bands at 1.4, 1.9, and 2.2 µm. Raman spectroscopy confirmed the presence of quartz, identified through unique vibrational peaks corresponding to its crystal structure (1).

The combination of LIBS, Raman, and infrared spectroscopy played a crucial role in these discoveries, allowing scientists to analyze rock chemistry, molecular structures, and hydration states remotely. LIBS provided elemental composition data by detecting plasma emissions from laser-ablated rock surfaces, revealing silica enrichment (1,2). Raman spectroscopy identified specific mineral phases based on vibrational modes, crucially distinguishing quartz from other silica polymorphs. Infrared spectroscopy, meanwhile, detected molecular absorption features, confirming the presence of hydrated silica and differentiating between opaline silica, chalcedony, and quartz. Together, these techniques provided a comprehensive picture of the mineralogical diversity in Jezero Crater and its potential hydrothermal history (1).

The study also examined three terrestrial reference samples—chert from Lake Magadi, sandstone from Fontainebleau, and hydrothermal quartz from Minas Gerais—to compare spectral and structural properties with Martian findings. The similarity of these samples to Martian quartz strengthens the hypothesis of hydrothermal precipitation (1).

Hydrothermal Processes and Potential Implications for Ancient Martian Life

Hydrothermal systems, known on Earth for their role in supporting microbial life, could have similarly provided habitable conditions on ancient Mars. The researchers suggest that Jezero’s silica-rich deposits likely formed due to hydrothermal activity, possibly triggered by the impact that created the crater. This aligns with previous detections of hydrated silica across Mars, including in Gale and Gusev craters, but the discovery of well-crystallized quartz sets this finding apart (1).

Opaline silica, recognized for its ability to preserve molecular and macroscopic biosignatures, presents an exciting target for astrobiological research. On Earth, some of the oldest microfossils have been discovered in chert, a quartz-rich rock formed from the transformation of hydrated silica. The protective properties of silica matrices help prevent molecular degradation, increasing the chances of preserving organic traces over geological timescales (1).

Mars Sample Return: A Future Opportunity for Further Study

While these silica-rich float rocks were too small for drilling and caching, the Perseverance team remains on the lookout for similar materials that could be collected as part of the Mars Sample Return (MSR) program. If quartz-bearing samples are retrieved and returned to Earth, they could provide unparalleled insights into the composition of ancient Martian fluids and potentially reveal trapped organic molecules within fluid inclusions (1). LIBS remains a vital technique for such planetary studies in the future (1,2).

The discovery of hydrated silica and quartz in Jezero Crater represents a significant step forward in unraveling Mars’ geological history. With ongoing exploration and future sample return missions, scientists may soon gain a deeper understanding of past hydrothermal activity and its implications for the potential preservation of ancient life on the Red Planet.

References

(1) Beck, P.; Beyssac, O.; Dehouck, E.; Bernard, S.; Pineau, M.; Mandon, L.; Royer, C.; Clavé, E.; Schröder, S.; Forni, O.; Francis, R. From Hydrated Silica to Quartz: Potential Hydrothermal Precipitates Found in Jezero Crater, Mars. Earth Planet. Sci. Lett. 2025, 656, 119256. DOI: 10.1016/j.epsl.2025.119256

(2) Seel, F.; Schröder, S.; Clavé, E.; Dietz, E.; Hansen, P. B.; Rammelkamp, K.; Hübers, H. W. Lifetime, Size, and Emission of Laser-Induced Plasmas for In-Situ Laser-Induced Breakdown Spectroscopy on Earth, Mars, and Moon. Icarus 2025, 427, 116376. DOI: 10.1016/j.icarus.2024.116376