Smectite formation in the presence of sulfuric acid: Implications for acidic smectite formation on early Mars.

ABSTRACT: The excess of orbital detection of smectite deposits compared to carbonate deposits on the martian surface presents an enigma because smectite and carbonate formations are both favored alteration products of basalt under neutral to alkaline conditions. We propose that Mars experienced acidic events caused by sulfuric acid (H₂SO₄) that permitted phyllosilicate, but inhibited carbonate, formation. To experimentally verify this hypothesis, we report the first synthesis of smectite from Mars-analogue glass-rich basalt simulant (66 wt% glass, 32 wt% olivine, 2 wt% chromite) in the presence of H₂SO₄ under hydrothermal conditions (~200 °C). Smectites were analyzed by X-ray diffraction, Mossbauer spectroscopy, visible and near-infrared reflectance spectr

SUBMITTER: Peretyazhko TS 

PROVIDER: S-EPMC7427815 | biostudies-literature | 2018 Jan

REPOSITORIES: biostudies-literature