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arXiv · 1703.06386

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

Edwin S. Kite·Jonathan Sneed·David P. Mayer·Sharon A. Wilson
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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.

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Edwin S. Kite, Jonathan Sneed, David P. Mayer, Sharon A. Wilson. 2018-11-22. Persistent or repeated surface habitability on Mars during the Late Hesperian - Amazonian. https://doi.org/10.1002/2017gl072660

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