A study of the absorption spectra in the Fe K near-edge region of four mineral samples of the pumpellyite-group with different total Fe content was performed. The Fe-rich samples from low-grade metamorphic rocks (Keweenawan basalts, Michigan; porphyrites from Torrente Bulla, Italy) essentially contain all structural Fe in the octahedrally coordinated trivalent state, in contrast to the commonly used crystal-chemistry rules for the computation of the pumpellyite chemical formula. The Fe in an iron-poor sample from high pressure environment (glaucophane-lawsonite bearing rock from Hicks Ranch, California) is shown to be 6-coordinated divalent iron, in agreement with previous structural studies on Al-rich pumpellyites.
XANES studies of Fe in pumpellyite-group minerals
ARTIOLI, GILBERTO;
1991
Abstract
A study of the absorption spectra in the Fe K near-edge region of four mineral samples of the pumpellyite-group with different total Fe content was performed. The Fe-rich samples from low-grade metamorphic rocks (Keweenawan basalts, Michigan; porphyrites from Torrente Bulla, Italy) essentially contain all structural Fe in the octahedrally coordinated trivalent state, in contrast to the commonly used crystal-chemistry rules for the computation of the pumpellyite chemical formula. The Fe in an iron-poor sample from high pressure environment (glaucophane-lawsonite bearing rock from Hicks Ranch, California) is shown to be 6-coordinated divalent iron, in agreement with previous structural studies on Al-rich pumpellyites.Pubblicazioni consigliate
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