2. Characterize the diversity and extent of different types of basaltic volcanism.
M3 target data of Lichtenberg Crater (20 km) and surrounding mare basalts. In this M3 color composite, younger basalts embaying topographic features south-east of Lichtenberg Crater are red due to a strong 1 m integrated band depth (IBD) and weak 2 μm ferrous band while older mare deposits to the southwest of Lichtenberg appear yellow due to strong ferrous absorptions at both 1 and 2 μms (red=1 μm IBD, green=2 μm IBD, blue= reflectance at 1.58 μm). This color composite has been overlaid on a M3 thermal channel at 2780 nm (as brightness) to show spectral variations in relation to the morphology of the crater and surrounding topography. Several small craters within the younger basalts appear to be excavating materials that are spectrally similar to older basalts to the west.
Basalts are the most common type of rock cooled from lava. Samples of basalts from the Moon's nearside, collected during Apollo and Luna missions, represent partial melts of the lunar mantle which occurred about 400-1000 million years after the crust and mantle separated into two distinct layers. However, remote sensing tells us that the basalts we have sampled represent only about a third of those on the lunar surface, and that there is great diversity in basalt composition and age, implying diversity in the mantle. The mineral character of basalts is best observed in the freshly exposed material surrounding small craters, which requires the kind of high spatial resolution of which M3 will be capable.
