Mössbauer study of two hornblendes and greenalite
Noor, Harun Mohd
MetadataShow full item record
⁵⁷Fe Mössbauer spectra have been recorded at room temperature and liquid nitrogen temperature for greenalite from Gyr greenstone belts of Yilgran Block, Western Australia and two hornblendes from the Sierra Nevada Batholith, California. Measurements at more than one temperature are found to provide information of value in isolating the separate components of the complex spectra for these minerals and categorizing these iron ions according to charge (Fe²⁺ , Fe³⁺) and spin (high, low) state. The greenalite spectra have been resolved into three doublets due to Fe²⁺ ions. The quadrupole splittings of all three doublets in greenalite spectra are strongly dependent on temperature which indicates that the Fe²⁺ ions are in the high-spin state. The spectra of hornblende sample H9A have been resolved into four doublets due to Fe²⁺ ions in M₁, M₃, M₄ sites and two doublets due to Fe³⁺ ions. The spectra of hornblende sample G55C have been resolved into three doublets due to Fe²⁺ ions in M₁, M₃, M₄ sites and two doublets due to Fe³⁺ ions. The large temperature dependence of quadrupole splittings of Fe²⁺ doublets and the small temperature-independent quadrupole splittings of the Fe³⁺ doublets are indicative of the high-spin state of iron ions.