Constraining ocean and ice shell thickness on Ariel from surface geologic structures and stress mapping

The Voyager 2 flyby of Ariel revealed this moon of Uranus to be a geologically complex world. Analysis of Voyager image data has revealed Ariel to host evidence of potentially cryovolcanic features and a system of fractures and basins which could be connected to geologic resurfacing in the past 1–2 Ga. A plausible stress source for this resurfacing is tidal stress from a higher orbital eccentricity in the geologically recent past due to chaotic orbital evolution during a past episode of mean-motion resonance with the other Uranian satellites. In this study, we compare stress modeling and geologic structures on Ariel's surface to constrain the interior structure and past orbital eccentricity which would be necessary to generate sufficient stress through eccentricity tides to result in geologic resurfacing at Ariel's surface. Our results suggest that an eccentricity of e ≥ 0.04 could generate stress sufficient to cause geological resurfacing at Ariel's surface, create a stress distribution consistent with the stress distribution inferred from Ariel's surface geology, and result in a ∼ 170 km thick subsurface ocean that existed within geologically recent (1–2 Ga) time.