Geological Chronicle
Rima Oppolzer is a lunar rille situated along the southern edge of Sinus Medii, within one crater diameter of the origin of the selenographic coordinate system at 0° N, 0° W. The channel spans a length of 110 km, passing through the southern part of the floor of Oppolzer crater and continuing to the east and west.
The host feature Oppolzer is the remnant of an impact crater whose interior floor was resurfaced by basaltic lava. Its surviving structure consists of an irregular arc of mounts along the south and a ring of scattered ridges along the northern rim, with a wide gap to the northeast where no ridges survive. Attached to the surviving remnants of the southeast rim is the crater Réaumur, while the lava-flooded walled plain Flammarion lies to the west-southwest.