Figure 4. Retrieval model results for the laboratory spectrum of sample K13. (A) Fit using the four library endmembers (Microcline, Oligoclase, Quartz, Clay+Magnetite). (B) The residual error (measured-modeled) shows the regions of poor fit over the large absorption bands. These errors approach 2% at 1050 cm-1 (9.5 microns) and 500 cm-1 (20 microns) and are due to unmodeled feldspar features. The average RMS error for this deconvolution iteration was 0.63% indicating a good fit [Ramsey, et al., 1999].