Figure 1 . MOLA hillshade regional map of the southern Tharsis Rise and the South Tharsis Ridge Belt (white dotted outline). Also shown are ridges initially mapped by Schultz and Tanaka [1994] (black lines), centers of Tharsis-driven tectonism [Anderson et al., 2001], including Claritas (A—Stage 1) and Pavonis (B—Stage 3), the Memnonia-Sirenum map [Anderson et al., 2019b] (white box) labeled [C], and the Bathys Planum map region (yellow box).
Bathys Planum is a provisionally named region of Mars located on the southwest periphery of the Tharsis Rise (Figure 1). This region may have been associated with the earliest stages of development of Tharsis [Anderson et al., 2001, 2019a; Dohm et al., 2001, 2007, 2009a]. Graben associated with both the Noachian (Stage 1) Claritas and early Hesperian (Stage 3) Pavonis tectonic centers, as identified by Anderson et al. [2001], transect this map region. Graben associated with both trends distinctly exhibit an unusual stair-stepping pattern in the Bathys Planum region (Figure 2).