Multispectral studies of western limb and farside maria from Galileo Earth-Moon Encounter 1

Results indicate that (1) western limb mare deposits have less variability in titanium content (<2-7 wt% TiO₂) and age (2.79-3.86 Ga) than areally extensive maria on the nearside; (2) areally extensive basin-filling maria generally have higher titanium contents than smaller, crater-filling mare patches and ponds; (3) ancient maria covered by highland material (cryptomaria) may be present in the Mendel-Rydberg and South Pole-Aitken basins; and (4) maria with compositional and age variations occur in the Grimaldi, Cruger, Mendel-Rydberg, and Apollo regions. No extensive high-titanium (>6 wt% TiO₂) mare basalts were observed on the western limb and farside, which may reflect the inability of such denser magmas to penetrate the thicker farside crust. -from Authors