Figure 10.

Modeled variation of (a) subsurface H₂O and (b) chlorine content of near‐surface materials along the Curiosity traverse, derived from neutron measurements by the DAN instrument. The units in Figure 10a are reported water‐equivalent hydrogen; no discrimination between H₂O and OH is implied. The units in Figure 10b are indicative of the Cl wt % present, but very large variations in other neutron absorbers like Fe, Ti, and Mn could modify chlorine‐equivalent concentrations from the true concentration of chlorine by 5–10% (relative; formally, the axis is ξCl as in Mitrafanov et al. [2014] and Litvak et al., 2016]).