Mars Study Explains Scarce Carbonates With 100,000-Year Water-Rock Reactions
Updated
Updated · EurekAlert · Sep 17
Mars Study Explains Scarce Carbonates With 100,000-Year Water-Rock Reactions
2 articles · Updated · EurekAlert · Sep 17
Summary
One-dimensional geochemical models show ancient Mars formed different carbonates depending on the starting rock: feldspar-rich crust readily yielded calcium/iron-rich carbonates, while mafic rock shifted toward magnesium-rich forms over time.
Simulations spanning a few years to 100,000 years found mafic rocks produced calcium/iron-rich carbonates only briefly, before dissolving magnesium-bearing minerals changed the water chemistry.
Percolating groundwater formed carbonates more efficiently than standing water but also dissolved near-surface deposits and reprecipitated them deeper underground, offering a mechanism for Mars' carbonate-poor surface.
The results suggest carbonate composition records not just climate and water history but crust type, making feldspar-rich terrains and subsurface drilling key targets for future Mars missions.