Fe compounds in scoria as distributed in the south-western area of Jeju Island were investigatedusing X-ray fluorescence spectroscopy, X-ray diffractometry, and 57Fe Mössbauer spectroscopy. The sampleswere prepared from four parasite volcanoes. It was found that these samples are typical basalt comprised ofSiO2, Al2O3, Fe, and silicate minerals. The Mössbauer spectra showed doublets for olivine, pyroxene, andilmenite as well as sextets for hematite and magnetite. The valence state of Fe is chiefly a 3+ charge statewith a slight 2+ charge state. It is expected that these results will add to the body of information related tothe formation mechanisms of Jeju Island.

Based on the X-ray powder diffraction (XRD) and M ssbauer spectroscopy, the thermal behavior and phase transformations of two clays are investigated for raw and fired conditions, which are collected from Kwangryeongli and Ildo district in Cheju Island. M ssbauer spectra at room temperature and 20for two clays show that paramagnetic Fe3- is the structural iron of the layer silicate and ferrihydrite, and superparamagnetic goethite has about 50% of total iron contents. The XRD peaks of hematite for the fired clays appear from 800℃ in Kwangryeongli clay and from 600℃ in Ildo district clay, respectively. The structural Fe2+ was completely oxidized into Fe3- at 400℃ for Kwangryeongli clay and 500℃~600℃ for Ildo district clay, respectively. The structural Fe2+ was completely oxidized into Fe3- at 400℃. For the temperature ranging from 400℃ to 700℃~800℃, two fired clays exhibit the dehydroxylation of the clay mineral. A disintegration of the clay mineral structure is observed from 700℃~800℃ to 1100℃, followed by the onset and spread of vitrification process. It is also shown that well-crystallized hematite phase is formed at the temperature higher than 1100℃ and the relative absorption area decreases, which might be related to the recrystallization of alluminosilicate matrix.