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. Author manuscript; available in PMC: 2021 Aug 20.
Published in final edited form as: J Geophys Res Planets. 2020 Mar 10;125(7):e2019JE006190. doi: 10.1029/2019je006190

Figure 18.

Figure 18.

(a) Centroid positions between 1 and 2 μm for a variety of materials. Dots show Fe/Mg-smectites of three different compositions from Fox et al. (2019) (navy), dunes from the study area (gray), Fe-bearing glasses from Cannon et al. (2017) (maroon), orthopyroxenes (OPX) from Klima et al. (2007) (magenta), low Ca-pyroxenes (LCP; red), and high Ca-pyroxenes (HCP; burnt orange) from Klima et al. (2011). Box plots show centroid of Blue Fractured Unit (BFU), LCP-bearing Plateaus Unit (LPU), and Mixed Lithology Plains Unit (MLPU) from two different CRISM scenes in NE Syrtis (FRT000161EF, Figure 12) and Nili Fossae (FRT00009D44, Figure 10). (b) Centroid positions of pyroxenes with different compositions from Klima et al. (2007, 2011) plotted in pyroxene quadrilateral. Note that an increase in Ca content generally causes a higher centroid position. (c) Mixing lines for pyroxenes of three different compositions (OPX, LCP, and HCP) with the three different Fe/Mg-smectites from Fox et al. (2019), a representative glass from Cannon et al. (2017), and representative dune composition. Smectite K, E, and J refers to smectite of compositions Ca0.23[Fe2.51Al0.26Mg0.12][Si3.51Al0.49]O10(OH)2, Ca0.40[FeIII1.06Mg0.93Al0.15][Si3.70Al0.30]O10(OH)2, and Ca0.37 [FeIII0.27Mg2.31Al0.08][Si3.60Al0.40]O10(OH)2 respectively. Boxplots of BFU, LPU, and MLPU are shown to the side for easy comparison. (d) Plots of centroid position and the D2300 band parameter from Pelkey et al. (2007) for pixels of BFU, altered BFU, LPU, and MLPU from the two different CRISM scenes.