Quantitative mass distribution models for Mare Orientale

Six theoretical models for the mass distribution of Mare Orientale were tested using five gravity profiles extracted from radio-tracking data of orbiting spacecraft. The models with surface mass and moho relief produced the best results. Although there is a mascon-type anomaly in the central maria region, Mare Orientale is a large negative gravity anomaly. This is produced primarily by the empty ring basin. Had the basin filled with maria material it seems likely that it would have produced a mascon such as those presently existing in flooded frontside circular basins.