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Valences and site characteristics of iron in radioactive magmatic veins (Egypt): A Mössbauer and chemical study.
- Source :
-
Mineralogia . 2010, Vol. 41 Issue 1, p23-33. 11p. 1 Color Photograph, 4 Charts, 2 Graphs, 1 Map. - Publication Year :
- 2010
-
Abstract
- 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. [ABSTRACT FROM AUTHOR]
- Subjects :
- *IRON
*MAGMAS
*GRANITE
*AUGITE
*NONFERROUS metals
Subjects
Details
- Language :
- English
- ISSN :
- 18998291
- Volume :
- 41
- Issue :
- 1
- Database :
- Academic Search Index
- Journal :
- Mineralogia
- Publication Type :
- Academic Journal
- Accession number :
- 64133635
- Full Text :
- https://doi.org/10.2478/v10002-010-0003-2