Geology of the Smythii and Marginis region of the Moon: Using integrated remotely sensed data

We characterized the diverse and complex geology of the eastern limb region of the Moon using a trio of remote-sensing data sets: Clementine, Lunar Pr ospector, and Apollo. On the basis of Clementine-derived iron and titanium maps we classify the highlands into low-iron (3-6 wt % FeO) and high-iron ( 6-9 wt % FeO) units. The association of the latter with basalt deposits wes t of Smythii basin suggests that the highland chemical variation is the res ult of mixing between basalt and highland lithologies. Mare Smythii and Mar e Marginis soils are compositionally similar, containing moderate iron(15-1 8 wt % FeO) and titanium (2.5-3.5 wt % TiO2). Smythii basin, in addition to the basalt deposits, contains an older, moderate-albedo plains unit. Our i nvestigation reveals that the dark basin plains unit has a distinct albedo, chemistry, and surface texture and formed as a result of impact-mixing bet ween highland and mare lithologies in approximately equal proportions. Clem entine iron and maturity maps show that swirls along the northern margin of Mare Marginis have the same iron composition as the surrounding nonswirl m aterial and indicate that the swirl material is bright because of its low a gglutinate content. Gravity data for the eastern limb show high, positive B ouguer gravity anomalies for areas of thin basalt cover (e.g., Smythii basi n and complex craters Joliot, Lomonosov, and Neper). We deduce that the upl ift of dense mantle material is the primary (and mare basaltic fill the sec ondary) source for generating the concentration of mass beneath large crate rs and basins.