Ra. Dunlap et al., A MOSSBAUER-EFFECT INVESTIGATION OF CORRELATED HYPERFINE PARAMETERS IN NATURAL GLASSES (TEKTITES), Journal of non-crystalline solids, 223(1-2), 1998, pp. 141-146
Room temperature Fe-57 Mossbauer effect spectroscopy has been used to
investigate the Fe quadrupole splitting distribution in tektites from
strewn fields in the Czech Republic (Moldavite), Australasia (Rizalite
) and North America (Bediasite). In all cases the Mossbauer effect spe
ctra show a broadened, slightly asymmetric quadrupole split doublet. T
wo quadrupole distributions, corresponding to Fe2+ and Fe3+ sites, hav
e been used tb-fit the resulting spectra. The Fe2+ distribution shows
two components corresponding to Fe with octahedral coordination and Fe
with tetrahedral coordination. The Fe3+ distribution shows a single c
omponent centered near zero splitting. Fe3+/Fe2+ ratios and Fe2+ tetra
hedral/octahedral ratios have been determined from the relative areas
of the various spectral components. Variations in the hyperfine parame
ters between samples from different strewn fields seem to be more sign
ificant than variations within a strewn field. Fitted parameters may b
e correlated with mean quadrupole splitting values and are discussed i
n terms of possible differences in tektite formation conditions. (C) 1
998 Elsevier Science B.V.