INSET: USGS IMAP 1196: Geologic map of the Sinus Sabaeus quadrangle of the Mars

The area included in the Sinus Sabaeus quadrangle represents an ancient cratered surface that has been modified by a combination of impact cratering, fluvial, eolian, and, probably, volcanic processes. Impact cratering has been the dominant process. Cumulative frequencies of craters larger than 20 km for the entire quadrangle (fig. 4) are only about a factor of two below the idealized...