Two new photo mosaics, created with images from NASA's Mars Global Surveyor spacecraft now in orbit at Mars, may help scientists understand what materials make up the exotic, multi-layers of the South Pole.

The layered terrains of the polar regions of Mars are among the most exotic planetary landscapes in our Solar System. The layers exposed in the south polar residual cap, vividly shown in the top view, are thought to contain detailed records of Mars' climate history over the last 100 million years or so. The materials that comprise the south polar layers may include frozen carbon dioxide, water ice, and fine dust. The bottom picture shows complex erosional patterns that have developed on the south polar cap, perhaps by a combination of sublimation, wind erosion, and ground-collapse. Because the south polar terrains are so strange and new to human eyes, no one has yet entirely adequate explanations as to what is being seen. Photo: NASA/JPL/MSSS

Scientists theorize that the thickness and the composition of the layers in the south polar region could hold a record of climate change in a way that is similar to how years of drought and years of plentiful rain change the width of rings in a tree trunk on Earth. Because the south polar terrain is so strange and new to human eyes, no one as yet has an entirely adequate explanation as to what is being seen. The layers may be made up of frozen carbon dioxide, water ice and fine dusts that have been eroded over time.

These images were acquired by the Mars Orbiter Camera aboard the Mars Global Surveyor spacecraft during the southern spring season in October 1999. Each of these two pictures is a mosaic of many individual MOC images acquired at about 12 m/pixel scale that completely cover the highest latitude (87 degrees S) visible to MOC on each orbital pass over the polar region. Both mosaics cover areas of about 10 x 4 kilometers (6.2 x 2.5 miles) near 87 degrees S, 10 degrees W in the central region of the permanent -- or residual -- south polar cap. They show features at the scale of a small house. Sunlight illuminates each scene from the left.

The mosaics were produced by imaging team scientists at the U.S. Geological Survey, Flagstaff, AZ and the California Institute of Technology, Pasadena, CA.

Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.

Mars Global Surveyor is managed by the Jet Propulsion Laboratory for NASA's Office of Space Science, Washington, DC. JPL is a division of the California Institute of Technology in Pasadena.