Map of the concentration of iron in the Aristarchus plateau. Using the 750-nanometer and 950-nanometer images, Lucey et al. (1995) developed a technique to determine the concentration of iron in lunar soils. This image is color-coded in increments of 2 wt%, with black being 0–2 wt% ferrous oxide and white being >18 wt% ferrous oxide. Note the high iron content of the surrounding mare lavas and the dark mantling deposits of the plateau. In contrast, Aristarchus Crater has penetrated the high-iron geological units, exposing the low-iron highland material that underlies the whole region.