Last updated on April 19, 2014 at 8:45 EDT
Archimedes - Mare Flooded Crater
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Archimedes - Mare Flooded Crater!

December 6, 2012
Archimedes is an 83 km diameter crater located in east Imbrium basin (29.7° N, 4.0° W). Archimedes is notable for its smooth floor, but unlike other craters with smooth floors, Archimedes is flooded with mare basalt. Craters with flooded floors are geologically important as they can establish relative ages of features thanks to the geologic law of superposition. Because both Archimedes and Imbrium basin are flooded by mare basalt, their formations must be older than the volcanic activity. Furthermore, because Archimedes is located within Imbrium basin, Archimedes must be younger than Imbrium. Just by studying relationships between features, scientists can piece together their history! Contact between Archimedes crater wall (bottom left) and floor (upper right). The floor is smooth and relatively flat compared to the sloped and rough elephant skin textured crater wall. LROC NAC M119883761, image width is 800 m [NASA/GSFC/Arizona State University].