Raman, FTIR and XRD study of Icelandic tephra minerals: implications for Mars

Essential to the success of proposed planetary Raman spectroscopy missions will be the preparation of comprehensive libraries of spectra and a greater understanding of the current limitations of Raman spectroscopy. Seven samples of Icelandic tephra were analysed using X-ray diffraction (XRD), Raman spectroscopy and Fourier transform infrared (FTIR) as an analogue for Martian rocks. The results from these three spectroscopic techniques were compared with the success of mineral identification of each method differing. Some minerals such as ilmenite and flouroapatite were identified using XRD and not found in the Raman spectra. Olivine, hematite and anatase were detected by Raman spectroscopy but were not observed in the XRD patterns. The FTIR results gave essential information on the presence of H2O in the samples. The impact of fluorescence on Raman spectra of some minerals is still a major concern as this is the most likely reason for some of the diagnostic mineral peaks not showing in the Raman spectra. Copyright (c) 2015 John Wiley & Sons, Ltd.