October 28, 2013

The Real Fracastorius

image by Damian Peach, U.K.

The well-known rille that crosses the center of the floor of Fracastorius crater is well shown, as are a variety of less frequently imaged rilles roughly perpendicular to the main one. Better seen than on any other terrestrial image I've found is the narrow rille that almost hugs the eastern floor of the crater, nearly in contact with the eastern wall. According to measurements from the LRO QuickMap this rille is only about 400 m wide. The southern (bottom) half of the floor of Fracastorius has a slightly swirled surface reminiscent of impact melt, but melt is unlikely to be visible in such an old crater that is so shallow. Melt should have veneered the original crater floor which must be buried beneath hundreds of meters of later fill of ejecta from other craters and basins.

Chuck Wood

Technical Details
September 24, 2013. C14.

Related Links
21st Century Atlas chart 6.
A synoptic view

Yesterday's LPOD: Ancient Fracastorius

Tomorrow's LPOD: 50 Years Later - not Forgotten, not Confirmed

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