Metamorphism in the Martian crust

• DOI: 10.1111/maps.12330
• Publication Date: 2014-07-08T21:43:43Z
• Authors: Harry Y. McSween; Theodore C. Labotka; Christina E. Vivi...
• Keywords: Ultramafic rock; Noachian

Abstract Compositions of basaltic and ultramafic rocks analyzed by Mars rovers occurring as Martian meteorites allow predictions metamorphic mineral assemblages that would form under various thermophysical conditions. Key minerals identified remote sensing roughly constrain temperatures pressures in the crust. We use a traditional approach (phase diagrams) to assess low‐grade/hydrothermal equilibrium assemblages. Basaltic should produce chlorite + actinolite albite silica, accompanied laumontite, pumpellyite, prehnite, or serpentine/talc. Only prehnite‐bearing have been spectrally on Mars, although laumontite pumpellyite spectra similar other uncharacterized zeolites phyllosilicates. Ultramafic are predicted serpentine, talc, magnesite, all which detected Mars. Mineral both fluid compositions be H 2 O‐rich CO ‐poor. confirm hypothesis metamorphism affected Noachian crust has excavated large craters. estimate geothermal gradient (>20 °C km −1 ) required observed This is higher than estimated from radiogenic heat‐producing elements crust, suggesting extra heating regional hydrothermal activity.