January 19, 2014
image by Christian VILADRICH
This is part of a beautiful, large mosaic, but I want to concentrate just on Copernicus, specifically its rim. The outline of the rim approximates a circle, but there are short straight segments and quite obviously a series (about 8?) of scallops or little bites out of the rim crest. Each is a where a small collapse of the rim crest occurred and usually there is a pile of crumpled debris at the bottom of the scarp - the material that moved downslope to cut the bite. A large semi-circular bite, 16 km wide, with the collapsed rim piece sitting as if in a bird's nest, is just on the southern part of the rim. The LRO NAC mosaic from QuickMap reveals horizontal layering. We can tell that this bite/collapse occurred during the formation of Copernicus and not later because there are impact melt ponds on top of it. Larger, elongate melt ponds are visible to the west of the bird's nest. The second remarkable rim feature is the tall, shadow-casting mountain rising above the east-southeast rim. This is the opposite of a bite, instead collapse has not pushed the rim away from the crater center quite as much as other places so the rim crest here is about 700 m higher than adjacent parts.
The image sent to me is labelled Copernic-C14-12dec2013.jpg
21st Century Atlas chart 17 & 22.
Yesterday's LPOD: Do You Have a Favorite Feature?
Tomorrow's LPOD: A Giant Hidden Hole?