Geologic map of the eastern equatorial region of Mars

The Mariner 9 mission in the early 1970’s provided the first comprehensive view of the geology of Mars (McCauley and others, 1972, Masursky, 1973) and led to the derivation of the first global geologic map (Carr and others, 1973). These preliminary studies were followed by more comprehensive mapping coordinated with the U.S. Geological Survey. Thirty quadrangles at a scale of 1:5,000,000 were produced in this map series, from which Scott and Carr (1978) compiled a single geologic map at a scale of 1:25,000,000. The reliability of these maps, however, is varied because of the uneven quality of the Mariner 9 data.