Cratering and obliteration history of Mars

The review presented is based mainly on the pre-Viking literature. Early interpretations of the Mariner 4 pictures of Martian craters are considered along with interpretations of Mariner 9 pictures. A description of cratering/obliteration models is presented and aspects of obliteration episode interpretation are discussed, taking into account large, intermediate, and small craters. Alternative interpretations of Martian cratering are also considered and questions of absolute chronology are investigated. The geomorphological processes described include exogenic, aeolian, and aqueous processes. The significance of the various processes and activities for the geomorphological evolution of Mars is evaluated.