The lunar south polar region (60°S–90°S) is being mapped at 1:2,500,000 scale using spacecraft data (Lunar Reconnaissance Orbiter, Clementine, Lunar Prospector, and Lunar Orbiter) to characterize geologic units, recognize contacts and structures, and identify impact craters (diameter [D] >2 km) for age dating. Most of the map area is located within the South Pole–Aitken basin, the largest (~2600 km) and oldest basin known on the Moon. At 18 km deep, South Pole–Aitken basin is believed to have exposed materials from the Moon's lower crust or upper mantle. Several large impact basins, such as Schrödinger basin (D = 334 km), are superposed on the floor of South Pole–Aitken and may have excavated through the floor of the basin. Thus, the materials that form the primary basin structures (rim and peak-ring) of Schrödinger, as well as the materials that cover its floor, may be used as proxies for the ancient lunar crustal and/or upper-mantle materials. Characterization of the materials that constitute Schrödinger and geologic mapping of the basin have identified nine units within the Schrödinger assemblage organized into three groups: basin materials, the plains formation, and the volcanic formation. The volcanic and plains materials found on the floor of Schrödinger exhibit flat expanses with smooth to rough surfaces and are dissected by floor fractures. These materials are interpreted to consist of impact melt and/or were emplaced by effusive eruptions of mafic materials, and they are some of the youngest materials in the basin, ranging from early Imbrian to early Eratosthenian in age.