New Research Suggests Subsurface Carbonates May Explain Mars' Missing Water

• Mars likely harbors extensive carbonate rock deposits beneath its surface, potentially resolving the long-standing scientific mystery regarding the planet's scarcity of these minerals despite its watery history.
• Geochemical simulations indicate that feldspar-rich rocks are highly efficient at producing the calcium and iron-rich carbonates observed on Mars.
• Groundwater percolation is identified as a more effective mechanism for carbonate formation than surface water, with evidence suggesting carbonates are dissolved near the surface and re-deposited at greater depths.

Scientific Context and Methodology

• Researchers from JAXA, the University of Tokyo, and the Earth-Life Science Institute (ELSI) conducted the study, published in JGR Planets.
• The team utilized one-dimensional thermochemical models based on the PHREEQC Version 3 geochemical code to simulate water-rock interactions under early Martian conditions.
• Simulations tracked geochemical alterations over durations ranging from a few years to 100,000 years, comparing mafic rocks with feldspar-rich varieties.

Implications for Future Exploration

• Findings suggest that drilling into feldspar-rich terrain could uncover definitive evidence of Mars' warmer, wetter past.
• Future exploration targeting underground aquifers may encounter these carbonate stores, providing crucial data on how the Martian climate transitioned to its current cold, dry state.
• The research offers a new framework for interpreting existing data from orbiters and rovers that have identified various rock types across the planet.