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Lat: 45.4°N, Long: 173.4°W, Diam: 57 km, Depth: km, Rükl: (farside)
external image normal_guillaume-clem1.jpgexternal image normal_Guillaume-LO-V-053-h1&h2.jpg
Left: Clementine, Right: LO-V-053-h1&h2


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(LAC zone 33A2) USGS Digital Atlas PDF


This is an unusual old crater. Normally as craters age they are modified by seismic shaking (from subsequent impacts), blasted by ejecta from nearby and distant impacts, and sometimes flooded by lavas. These modifications produce a typical aged crater with smooth walls, filled in floor and buried central peaks - there are many craters in the nearside southern hemisphere that look like that. Guillaume is similar in that its terraces are gone and it has a wide flattish floor, but it also has a broad and low central mound. This looks like what happens when a crater relaxes isostatically - that is, the rock that it has formed in slowly deforms by flowage. The rounded rim of Guillaume supports this interpretation. How could this one crater be isostatically compensated when its neighbors aren't? Well, maybe it's not; perhaps its just an unusual modification pattern. But it could be because it is older than its neighbors. Perhaps it formed in a region of the crust that was warm enough to deform slowly. By the time the later craters formed the crust had cooled and become rigid. There may be other old craters that have been compensated but are harder to identify as craters. For example, if there were a few more craters like the cluster of craters on Guillaume's eastern rim (basin secondaries?) and the scattered craters on the western side, the crater would nearly disappear, and the rounded central mound would just be an accident of topography. - tychocrater Aug 11, 2007

Description: Wikipedia

This name is not printed on lunar farside maps such as Hallwag's or Antonin Rukl's.- DannyCaes Dec 4, 2011

Is it a rille? Or a fault? Or a scarp?

What sort of feature is running halfway between Guillaume and Guillaume D?
Is it a rille? Or a fault? Or perhaps a scarp? Or something else? See:


Charles Edouard; Swiss metallurgist; Nobel laureate (1861-1938).
Rima Guillaume (an unofficial name for the strange feature halfway between Guillaume and Guillaume D).

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