Pacing Early Mars fluvial activity at Aeolis Dorsa: Implications for Mars Science Laboratory observations at Gale Crater and Aeolis Mons

TL;DR

This study estimates sedimentation rates and duration of early Mars fluvial activity at Aeolis Dorsa and Gale Crater, providing insights into the timeline of Martian geological processes during the Noachian-Hesperian transition.

Contribution

It introduces a method combining crater burial observations and impactor flux models to constrain sedimentation rates and durations of early Martian fluvial activity.

Findings

Sedimentation rate at Aeolis Dorsa is estimated between 20-300 μm/yr.

Fluvial activity around the Noachian-Hesperian transition lasted at least 1-15 million years.

Gale Crater's mound formation took at least 10-100 million years.

Abstract

The impactor flux early in Mars history was much higher than today, so sedimentary sequences include many buried craters. In combination with models for the impactor flux, observations of the number of buried craters can constrain sedimentation rates. Using the frequency of crater-river interactions, we find net sedimentation rate \lesssim 20-300 {\mu}m/yr at Aeolis Dorsa. This sets a lower bound of 1-15 Myr on the total interval spanned by fluvial activity around the Noachian-Hesperian transition. We predict that Gale Crater's mound (Aeolis Mons) took at least 10-100 Myr to accumulate, which is testable by the Mars Science Laboratory.