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

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

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.

Abdel Monem, H.M., & El-Afandy, A.H. (1997). Geochemistry of beneficiation studies of U-Th bearing minerals of Um Risha ring complex, Eastern Desert, Egypt. Egyptian Mineralogist, 9, 43-58.

Biscaye, P.E. (1965). Mineralogy and sedimentation of recent deep-sea clays in the Atlantic Ocean and adjacent seas and oceans. Geological Society of America Bulletin, 76, 803-832.

Cameron, M., Sueno, S., Prewitt, C.T., & Papike, J.J. (1973). High-temperature crystal chemistry of Acmite, diopside, hedenbergite, jadeite, spodumene, and ureyite. American Mineralogist, 58, 594-618.

De Grave, E., Van Alboom, A., & Eeckhout, S.G. (1998). Electronic and magnetic properties of a natural aegirine as observed from its Mössbauer spectra. Physics and Chemistry of Minerals, 25, 378-388.

Dollase, W.A., & Gustafson, W.I. (1982). Mössbauer spectral analysis of the sodic clinopyroxenes. American Mineralogist, 67, 311-327.

Dyar, M.D., McEnroe, S.A., Murad, E., Brown, L.L., & Schiellerup, H. (2004). The relationship between exsolution and magnetic properties in hemo-ilmenite: Insights from Mössbauer spectroscopy with implications for planetary magnetic anomalies. Geophysical Research Letters, 31, L04608. DOI: 10.1029/2003GL019076.

Hassan, K.M. (2005). Geochemical assessment of radioactive lava pockets in El-Seboah granite, Toshki area, south Western Desert, Egypt. Annals of the Geological Survey of Egypt, 28, 195-204.

Hassan, K.M. (2008). Characterization of granitic soil samples from Egypt by 57Fe Mössbauer spectroscopy. Isotope and Radiation Research, 40, 107-116.

Hassan, K.M. (2009a). Rhyolite-dacite-trachyandesite association: a Mössbauer spectroscopy study. Hyperfine Interactions, 192, 101-107.

Hassan, K.M. (2009b). Characterization of granites by 57Fe Mössbauer spectroscopy. Mineralogia, 40(1-4), 95-106.

Khalaf, I.M., Abdel Monem, A.A., Attawiya, Y.M., Ammar, S.E., & El-Sawey, E.H. (2000). Petrology, geochemistry and radioactivity of Abu Aqarib Alkali granite, Central-Eastern Desert, Egypt. Annals of the Geological Survey of Egypt, 38, 261-274.

Kuzmann, E., Nagy, S., & Vértes, A. (2003). Critical review of analytical applications of Mössbauer spectroscopy illustrated by mineralogical and geological examples. Pure Applied Chemistry, 75, 801-858.

List, F.K., El-Gaby, S., & Tehrani, R. (1989). The basement rocks in the Eastern and Western Deserts and Sinai. In M. Hermina, E., Klitzsch & S. List (Eds.), Stratigraphic lexicon and explanatory note to the geologic map of Egypt 1:500000 (pp. 33-56). Cairo, Egypt: Egyptian General Petroleum Corporation.

Marks, M., Vennemann, T., Siebel, W., & Markl, G. (2003). Quantification of magmatic and hydrothermal processes in a peralkaline syenite-alkali granite complex based on textures, phase equilibria, and stable and radiogenic isotopes. Journal of Petrology, 44, 1247-1280.

Mc Birney, A.R. (1984). Igneous petrology. California: Freeman Cooper & Company.

McCanta, C., Rutherford, M.D., Dyar, M.D., & Delaney, J.S. (2003). Fe3+/ΣFe ratios in pigeonite as a function of ƒO2: a preliminary investigation. Proceedings - 34th Lunar and Planetary Science Conference, 17-21 March 2003 (Abstract 1361). Lunar and Planetary Institute. League City, Texas, U.S.A.

McCanta, C., Rutherford, M.D., Dyar, M.D., & Delaney, J.S. (2004). The relationship between clinopyroxene Fe3+ content and oxygen fugacity. Proceedings - 35th Lunar and Planetary Science Conference, 15-19 March 2004 (Abstract 1198). Lunar and Planetary Institute. Houston, Texas, U.S.A.

McCarthy, A.C., Downs, R.T., Thompson, R.M., & Redhammer, G.J. (2008). In situ high-pressure single-crystal X-ray study of aegirine, NaFe3+Si2O6, and the role of M1 size in clinopyroxene compressibility. American Mineralogist, 93, 1829-1837.

Murad, E. (1982). The characterization of goethite by Mössbauer spectroscopy. American Mineralogist, 67, 1007-1011.

NMA (2000). Toshki project phase I. Maadi, Kattamyia, Cairo, Egypt: Nuclear Materials Authority.

Poppe, L.J., Paskevich, V.F., Hathaway, J.C., & Blackwood, D.S. (2001). U. S. Geological Survey Open-File Report 01-041 (A laboratory manual for x-ray powder diffraction) from http://pubs.usgs.gov/of/2001/of01-041/index.htm

Scott, W.W. (1958). Standard Methods of Chemical Analysis. New Jersey: D. Van Nostrand Company Inc.

Scott, W.W., & Furman, N.H. (1952). Standard methods of chemical analysis (5 ed.). New York: Van Nostrand Company Inc.

Secco, L., Guastoni, A., Nestola, F., Rehammer, G.J., & Negro, A.D. (2007). Crystal chemistry of aegirine as an indicator of P-T conditions. American Mineralogist, 71, 249-255.

Welcher, F.J. (1958). The analytical uses of ethylenediaminetetraacetic acid. New Jersey: D. Van Nostrand Company Inc.

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