Gypsum, a common mineral composed of calcium sulfate, lies
scattered in this newly-released image of the Olympia Undae
region of Mars. The picture was made by combining CRISM data
with HiRISE observations, and has the same resolution
characteristics of the Nili Fossae image. Made on October 1,
2006, the image covers about 12 square kilometers (7.5 sq. mi.).
Gypsum, used commonly on Earth as the substance in wallboard, is
a sulfate-rich mineral that forms by evaporation and requires
large amounts of water for its formation. In this image,
brighter areas contain more gypsum and darker areas less so. The
bottom views are enlargements of the central part of the two
versions of the image shown at top. Could this large gypsum
deposit be the dead mineral remains of a once mighty sea that
occupied this area of the Red Planet?