Study of ordinary chondrites by Moessbauer spectroscopy with high velocity resolution: identification of M1 and M2 sites in silicate phases

Study of ordinary chondrites by Moessbauer spectroscopy with high velocity resolution revealed for the first time two crystallographically nonequivalent octahedral sites M1 and M2 in the subspectra of olivine and pyroxene that were observed previously in pure natural or synthetic silicates only. Moessbauer hyperfine parameters and relative areas related to M1 and M2 sites in olivine and pyroxene determined from Moessbauer spectra of ordinary chondrites were analyzed and compared with parameters of pure natural and synthetic silicates. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)