Fig. 3. Total Fe expressed as wt % FeO of the igneous samples shows a correlation with the calibrated emissivity at 0.86 μm.
Error bars represent leave-one-out cross-validation (LOO-CV) for linear regression. FeO contents to be derived for the Venera 9 and 10 landing sites based on their spectral measurements [reflectance converted to emissivity with associated error bars digitized from figure 8 of Ekonomov et al. (19): εVenera9 is ±0.04 and εVenera10 is ±0.02]. On the basis of this analysis, Venera 9 has 12.2 wt % FeOtotal and Venera 10 has 9.5 wt % FeOtotal. XRF, x-ray fluorescence.