The Thermo-Chemical Evolution of Europa: Constraints on Silicate Volcanism at Europa's Ocean Floor

Abstract

One of the key factors for Europa's habitability is the level of internal activity and its possible consequences, e.g. volcanism, at the ocean floor. Tidal dissipation in the silicate mantle would affect Europa's thermal state with consequences for the long-term existence of an ocean and -in case of volcanism- for ocean chemistry. In parameterized thermo-chemical evolution models we consider the thermal coupling between an iron-rich core, a silicate mantle and a water/ ice layer. The models further include tidal heating in both the silicate and the ice. Models without tidal heating already suggest that partial melt in the silicate mantle can be maintained up to a few billion years. In that case, tidal heating in the silicate shell will become important, prolonging the lifetime of partially molten reservoirs and associated ocean-floor volcanism. Heating of the silicate mantle would also affect the thermal state and thickness of the ice shell. Additionally, tidal heating in the mantle may impede the generation of a self-sustained magnetic field in Europa's core. We will discuss consequences of time-dependent orbital parameters due to the resonance locking with Io and Ganymede on Europa's thermal state.