Image: U.S. Geological Survey geologic maps of Mars: left, Greeley and Guest (1987) Map I-1802-B; right, Scott and Tanaka (1986) Map I-1802-A
Portions of global geologic maps of Mars derived from Viking data, with MFF units outlined in red. The equator of Mars runs through the middle of the image; each grid box corresponds to 10 by 10 degrees (roughly 590 by 590 km).
This image illustrates a paper by Smithsonian scientists James R. Zimbelman and Stephen P. Scheidt, “Hesperian age for western Medusae Fossae Formation, Mars” scheduled for publication in the June 29 issue of the journal Science.
