This THEMIS image of rounded hills and ridges in Arcadia Planitia shows a very intriguing geomorphic feature that may be attributed to the presence of an icy-rock mixture of material. Smooth aprons of material are observed to be preferentially located on the cold, north facing slopes of hills and extend further and beyond the deposits located on other sides. These smooth deposits are in stark contrast to the more rough surfaces that dominate the scene and it has been suggested that they represent a preserved mixture of ice and rock. How exactly this deposit forms still remains a mystery. They may have been ?pasted? onto the slopes and preserved on the cold facing sides or they may represent the result of downslope motion of material that is enhanced by the presence of ground ice. In either case, this interesting observation suggests that ground ice may still play an important role in the formation and preservation of martian surface features.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.