|Lat: 68.1°S, Long: 146.9°W, Diam: 94 km, Depth: km, Rükl: (farside)|
Crommelin lies some 800 kilometres south-east from the main central region of the South-Pole Aitken Basin -- a 2500 kilometre-wide basin of the pre-Nectarian period (~ 4.6 to 3.92 bn years). The crater is barely perceptible amongst an amalgamation of impact craters of all sizes (most particularly of small craterlets) that have shapened nearly most of Crommelin's outer ramparts, its well-worn rim, and interior floor. Several of the major, younger impact events on the outer northern sectors of the crater, for example, Crommelin C to its north-east and Crommelin X to its north-west (and the smalller craters in between) have imparted material onto the floor of Crommelin. It looks like this material, too, has subsequently been covered over by later material from another series of impact events whose craters (craterlets) dominate the whole of the floor's history; making it hard to ditinguish features like the collapsed wall south-east of Crommelin X, the southern part of the large crater within the northern sector of Crommelin, and, of course, the central peak now barely recognisable. But where have all these young, destruct-like craters (craterlets) come from? Looking at both the inside and outside regions of Crommelin as a whole, perhaps we're looking at secondaries and tertiaries produced from the main impact-basin events nearby, like those, for example, of the Mendel-Rydberg Basin some 700 km east-north-east of the crater, or the Orientale Basin some 2000 km away in a north-easterly direction? Probably, a combination of both (and others in the region) is responsible, however, from the freshness of most of the craters (craterlets) seen in the region, not to mention the radial, chain direction of some, the most likely candidate is Orientale. - JohnMoore2
Andrew Claude De La Cherois; British astronomer (1865-1939).