Valences and site characteristics of iron in radioactive magmatic veins (Egypt): A Mössbauer and chemical study

• Autorzy: Hassan K. M.

Identyfikatory

DOI

10.2478/v10002-010-0003-2

• Języki publikacji: EN

Abstrakty

EN

Radioactive veins in shear zones of the El-Seboah granite in Egypt with anomalous concentrations of Nd, Ce, Zr, Y, Nb, Sm, Th and U were studied by petrographic microscopy, x-ray diffraction, 57Fe Mössbauer and wet chemical methods. The veins are composed essentially of quartz, aegirine-augite and minor K-feldspar ± α-iron oxide (hematite) ± γ-iron oxide hydroxide (goethite). They likely represent late-stage felsic melt that was quenched and devitrified at high temperature to yield crystals and crystallites, and then subjected to low temperature alteration during which most of the K feldspar transformed to kaolinite and opal. Mössbauer parameters of the samples indicate that the existing Fe-bearing minerals are primary, with appreciable ordering in the Fe sites. The bulk-sample iron (ΣFe) contents are extremely high (12.3-22.4%). The extent of oxidation of the Fe has been found to be 100% by Mössbauer spectroscopy and 95.36-99.69% by a chemical method. These conditions of Fe enrichment and strong oxidation suggest that the veins are extreme differentiates of granite magmas where high states of oxygen fugacity prevailed.

Słowa kluczowe

EN

Egypt; Mössbauer; peralkaline rocks; aegirine-augite; Fe-oxide phases; radioactive/rare metals

• Wydawca: Mineralogical Society of Poland
• Czasopismo: Mineralogia
• Rocznik: 2010
• Tom: Vol. 41, iss. 1/2
• Strony: 23--33
• Opis fizyczny: Bibliogr. 25 poz., rys., tab., wykr.

Twórcy

autor

Hassan K. M.

• Nuclear Materials Authority, P.O. Box 530, Maddi, Cairo, Egypt

Bibliografia

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