Elastic thickness and heat flux estimates on Ganymede

Abstract

We identify sites of apparentflexural uplift at rift zone boundaries on Ganymede using Galileo stereo-derived topography. The estimated effective elastic thickness Te is 0.2-0.6 km for a nominal Young's modulus of 1GPa. Using a viscoelastic model of the ice crust we find that the ratio of Te to conductive lid thickness is <0.5. The inferred local heat flux during deformation is less than 480mWm^-2, an probably close to60mWm^-2. This value is an order of magnitude greater that the present-day radiogenic heat flux. The stresses required to cause fault motions are around 1MPa. Both the high heat flux and the higher stresses are consistent with estimates of these quantities during an episode of transient tidal heating in Ganymede's past.