Geological Chronicle
Situated on the western margin of Oceanus Procellarum, Cavalerius is an impact crater spanning 59.35 kilometers across that nearly touches the northern rim of the larger walled plain Hevelius to its south. The formation lies in the western hemisphere of the visible Moon, with the Reiner Gamma magnetic albedo feature positioned to the east-northeast. In 1966, the Soviet probe Luna 9 performed the first successful lunar soft landing northeast of Cavalerius at Planitia Descensus.
Geochronological estimates date the crater to 3.2±0.2 billion years ago, placing its formation within the Eratosthenian period on the lunar geologic timescale. Its perimeter is defined by a sharp rim rising to over 3 kilometers in places, marked by clefts along its northern and southern sections and terraced inner walls with slumping evident.
The interior floor mixes hummocky patches, low hills, and level areas around a low central peak flanked by ridges to the north and east. The crater floor appears rich in clinopyroxene and olivine, while the walls and rim display abundant indications of orthopyroxene.
Italian astronomer Giovanni B. Riccioli introduced the feature's name in 1651 to honor mathematician Buonaventura Cavalieri, and the designation gained official recognition when the International Astronomical Union adopted it in 1935.