Figure 15.

Principal component analysis biplots of ChemCam of Namib Dune targets (excluding the nighttime data from GB_A) with oxides contributing to each factor indicated for (a) principal components 1 and 2 and (b) principal components 3 and 4. Methodology is the same as in Figure 9. Sands are color coded for undisturbed (Dwyka), disturbed (Doros, Husab, Gosser_Scuff), the fine fraction of sieved materials (<150 um; GB_A), and the coarse fractions of sieved materials (GB_B, GB_C, GB_D). “Diff_from_100” is the difference in the oxide weight percent totals from 100%, a proxy for volatiles and/or minor elements.