Measuring timespans recorded in river deposits is a key goal in better understanding ancient environments on Earth and Mars (Paola et al., 2018). On Mars, using river deposits is particularly useful because most geochronological methods to constrain depositional timespans are unavailable. Moreover, it is unclear whether early Mars had a long-lived, stable hydrological cycle or multiple intermittent, short-lived, river-forming episodes (e.g.,