Light-toned layered deposits in Crater Terby and the Greater Hellas Region, Mars
Mars today is cold and dry and liquid water is not stable at the surface. There are several landforms that suggest the climate on Mars was once warmer and wetter - similar to Earth. Scientists have been intrigued by the discovery of layered deposits on Mars since they were recognized by Mariner 9 and Viking orbiters in the 1970s. Many of the layered deposits on Mars are light-toned, occur in crater interiors, and are characterized by thick, laterally continuous, repetitive sequences. There are many ways in which layered deposits can form on Mars, including volcanic, wind or water-related processes. The physical and chemical nature of the light-toned layered deposits in Terby crater and other craters around the great Hellas impact basin are consistent with deposition of material in a large, standing body of water much earlier in Mars' history.