NASA’s Perseverance rover discovered unexpected igneous rocks in Mars’ Jezero Crater, revealing complex water interactions that challenge previous assumptions about the planet’s watery past. The findings, published in Communications Earth & Environment, show carbonate minerals formed through multiple aqueous events, while a separate study in Nature analyzed mineral clusters in the Margin Unit. Meanwhile, Caltech researchers identified a heat anomaly in Mars’ southern hemisphere, and a JAXA-led study suggested underground carbonates could explain the planet’s missing water.
NASA’s Perseverance rover
Margin Unit
Unexpected Igneous Rocks Reveal Mars’ Watery History
NASA’s Perseverance rover found igneous rocks in the Margin Unit of Jezero Crater, contradicting expectations of sedimentary layers. These rocks, formed from magma or volcanic activity, preserved evidence of at least three water interactions, including carbonate and silica deposits. Before we arrived at the Margin Unit, the main hypothesis — derived from orbital observations — was that the carbonate seen from orbit formed from interaction with the lake that existed in Jezero Crater,
said Candice Bedford, a Purdue University scientist and lead author of the Communications Earth & Environment study. But now we know this location became a crossroads for aqueous systems. The rover’s SuperCam instrument analyzed 185 bedrock targets, revealing how water altered the rocks over time.
SuperCam
Cluster Analysis Unveils Complex Mineralogical Patterns
A Nature study used cluster analysis to classify 356 SuperCam data points from the Margin Unit, identifying eight distinct mineralogical groups. These included Fe/Mg-rich carbonates, silica-rich phases, and iron-rich clusters. The analysis showed olivine, a magnesium-iron silicate, transformed into carbonate and silica through water interactions. Turning olivine into carbonate leaves silica behind, and we see more of that silica in rocks below the waterline, said Eleni Ravanis, a researcher involved in the study. The dataset was divided into eight clusters, with 356 data points (22% of the dataset) classified as “mixed” due to weak cluster relationships. Cluster 1 (17% of data) was characterized by low SiO2 (16.3 ± 4.5 wt%) and TiO2 (0.04 ± 0.08 wt%), high MgO (35.1 ± 6.0 wt%), and elevated C scores, suggesting a Fe/Mg-rich carbonate component. Cluster 3 (25% of data) had moderate SiO2 (44.1 ± 4.6 wt%) and FeOT (24.1 ± 3.4 wt%) but high MgO (31.6 ± 5.3 wt%), aligning with olivine found in proximity science instruments.
Caltech
Mars’ Southern Hemisphere Shows Unusual Thermal Anomaly
Caltech researchers, publishing in Nature, discovered a 200–400°C heat anomaly deep in Mars’ southern hemisphere. This thermal asymmetry, linked to the planet’s north-south topographic divide, suggests complex internal processes. Mars isn’t perfectly spherical,
said Alexander Berne, lead author of the study. The southern interior is much hotter, possibly due to thick geological features trapping heat. The team used gravity data from Mars missions—Mars Global Surveyor, Mars Odyssey, and Mars Reconnaissance Orbiter—to model the planet’s interior, revealing an unbalanced structure that challenges previous assumptions about Mars’ thermal evolution. The findings were published on August 26, 2026.
JAXA
Groundwater May Have Buried Carbonates, Hiding Mars’ Watery Past
A JAXA-led study in JGR Planets suggests groundwater interactions could explain the scarcity of surface carbonates on Mars. By simulating water-rock reactions, researchers found feldspar-rich rocks produce calcium/iron-rich carbonates, while mafic rocks favor magnesium-rich varieties. Feldspar-rich terrain could reveal evidence of Mars’ warmer, wetter past, said Chang-Chin Wang, a doctoral student at JAXA. The study also showed groundwater efficiently forms carbonates but may have reprecipitated them underground as the climate cooled. The research, led by JAXA’s Chang-Chin Wang, Tomohiro Usui, and Mohit Melwani Daswani, compared observational data to simulations, highlighting feldspar-rich rocks as potential indicators of past water activity.
The discoveries collectively paint a picture of Mars as a planet where water activity was both persistent and complex. From the Margin Unit’s mineralogical diversity to the southern hemisphere’s thermal anomaly, each finding adds layers to our understanding of the Red Planet’s geological and hydrological history. As NASA and JAXA continue to analyze data, the next steps involve deeper drilling and more precise modeling to unlock Mars’ remaining secrets.