Detection of ferrihydrite in Martian red dust records ancient cold and wet conditions on Mars.

ABSTRACT: Iron oxide-hydroxide minerals in Martian dust provide crucial insights into Mars' past climate and habitability. Previous studies attributed Mars' red color to anhydrous hematite formed through recent weathering. Here, we show that poorly crystalline ferrihydrite (Fe₅O₈H · nH₂O) is the dominant iron oxide-bearing phase in Martian dust, based on combined analyses of orbital, in-situ, and laboratory visible near-infrared spectra. Spectroscopic analyses indicate that a hyperfine mixture of ferrihydrite, basalt and sulfate best matches Martian dust observations. Through laboratory experiments and kinetic calculations, we demonstrate that ferrihydrite remains stable under present-day Martian conditions, preserving its poorly crystalline structure. The persistenc

SUBMITTER: Valantinas A 

PROVIDER: S-EPMC11861699 | biostudies-literature | 2025 Feb

REPOSITORIES: biostudies-literature