August 31, 2004

Archimedes and his Mountains

Image Credit: K.C. Pau

Archimedes and his Mountains Archimedes is the largest crater inside the Imbrium Basin (Sinus Iridum is bigger but its on the rim rather than inside). But I don't think it is observed much because its floor lacks a central peak and its small pits, unlike Plato's, haven't become known as a test for seeing and optics. But south of Archimedes is an area that is even less often observed. The Archimedes Mountains are two crude arcs that run NE to SW, with a gentle curve inwards towards Imbrium. These mountains appear to be part of a 790 km wide inner ring of the Imbrium Basin, probably formed as a mega-terrace, as massive arcs of land slumped toward the hole created by the Imbrium impact. The mountains are in the midst of an area of low hills and small craters. This surface, lighter than nearby mare, is an area of KREEP volcanism called the Apennine Bench. This volcanic material was erupted onto the floor of the Imbrium basin and later was surrounded by normal mare basalts. — Chuck Wood Technical Details: Aug 7, 2004, 10" f/6 Newtonian + 5X Barlow + Phillips Toucam Pro, 3 image mosaic. KREEP = Potassium, rare-earth elements and phosphorus rich basalts unique to the Imbrium area. Related Links: Geology and Composition of the Apennine Mountains Lunar Orbiter IV View Yesterday's LPOD: Are Central Peaks Volcanoes? Tomorrow's LPOD: Hundred Year Old Hevelius

Author & Editor: Charles A. Wood COMMENTS? Register, Log in, and join in the comments.