The east rim of Hellas basin is a complex geologic region affected by volcanic, tectonic, channeling, and resurfacing processes. A regional geologic map of the area between 27.5-42.4 degrees S and 260-275 degrees W was compiled in order to establish general stratigraphic relationships between and among the geologic units exposed in the region. The southern one-third of the regional map, the area convered by three MGM 1:500,000 quadrangles -40272, -40267, and -40262, is to be mapped in more detail in this project. Outflow channel deposits were subdivided into three facies and interpreted. A geologic sketch map of the Hadriaca Patera region on the east rim of the Hellas basin is presented.
