The origin of selected lunar geochemical anomalies Implications for early volcanism and the formation of light plains

The geochemical anomalies on the eastern limb and far side of the moon are presently identified and characterized, and their formation processes are investigated, in light of Apollo spacecraft geochemical and photogeologic remote sensing data sets. The results of recent spectral reflectance studies of dark-haloed impact craters, together with considerations of anomaly surface chemistry, indicate that the geochemical anomalies associated with light plains deposits displaying dark-haloed impact craters are due to basaltic units that are either covered by varying thicknesses of highland debris or have a surface contaminated by significant amounts of highland materials.