Elastic Thickness and Heat Flux Estimates on Ganymede

Abstract

We identify sites of apparent flexural uplift associated with grooved terrain formation and rifting on Ganymede using Galileo stereo-derived topography from the G28 orbit. The estimated effective elastic thickness Te is found to be 0.2-0.6 km for a nominal Young's modulus of 1 GPa. Using a viscoelastic model of the ice lithosphere we find that the ratio of Te to conductive lid thickness is < 480 mW m-2, and probably close to 60 mW m-2. This value is an order of magnitude greater that the present-day radiogenic heat flux. Based on fault block topography, the stresses required to cause fault motion are consistent with estimates of these quantities during an episode of transient tidal heating in Ganymede's past.