Geological Chronicle
Lyman is a lunar impact crater spanning 83.25 kilometers in diameter in the southern hemisphere on the far side of the Moon. Located south of the huge walled plain Poincaré and northeast of Schrödinger, the feature honors American physicist Theodore Lyman.
Dating to the Late Imbrian epoch, Lyman has not been significantly worn and retains a well-defined edge and interior features uneroded by impacts. Its perimeter is roughly circular with outward bulges along the southern and eastern edges where slumping has occurred, while collapsed material forms a ring-shaped pile around the edge of the interior floor alongside inner-wall terraces.
The interior floor is relatively level, marked by minor ridges, small craterlets, and a central peak with attached foothills to the north and northeast. Spectral data for this orthopyroxene-rich peak fits a gabbroic norite mineralogy originating from a depth of 8.4 to 13.3 kilometers.