Persistent or repeated surface habitability on Mars during the Late Hesperian - Amazonian

Abstract

Large alluvial fan deposits on Mars record relatively recent habitable surface conditions ($\lesssim$3.5 Ga, Late Hesperian - Amazonian). We find net sedimentation rate <(4-8) μm/yr in the alluvial-fan deposits, using the frequency of craters that are interbedded with alluvial-fan deposits as a fluvial-process chronometer. Considering only the observed interbedded craters sets a lower bound of >20 Myr on the total time interval spanned by alluvial-fan aggradation, >10^3-fold longer than previous lower limits. A more realistic approach that corrects for craters fully entombed in the fan deposits raises the lower bound to >(100-300) Myr. Several factors not included in our calculations would further increase the lower bound. The lower bound rules out fan-formation by a brief climate anomaly. Therefore, during the Late Hesperian - Amazonian on Mars, persistent or repeated processes permitted habitable surface conditions.

References in corpus (3)

• Stratigraphy of Aeolis Dorsa, Mars: stratigraphic context of the great river deposits
• Mars sedimentary rock erosion rates constrained using crater counts, with applications to organic matter preservation and to the global dust cycle
• Localized precipitation and runoff on Mars

Cited by in corpus (8)

• A warmer and wetter solution for early Mars and the challenges with transient warming
• Methane bursts as a trigger for intermittent lake-forming climates on post-Noachian Mars
• Voluminous silica precipitated from martian waters during late-stage aqueous alteration
• Albedos, Equilibrium Temperatures, and Surface Temperatures of Habitable Planets
• Changing spatial distribution of water flow charts major change in Mars' greenhouse effect
• Effect of Mars Atmospheric Loss on Snow Melt Potential in a 3.5-Gyr Mars Climate Evolution Model
• Climates of Warm Earth-Like Planets III: Fractional Habitability from a Water Cycle Perspective
• High and dry: billion-year trends in the aridity of river-forming climates on Mars