Abstract
Quartz-diorite, gneissose granodiorites, two-mica granite and perthite leucogranie are the main rock units cropping out in the Wadi Ghadir area, South Eastern Desert of Egypt. Along the NNE-SSW mega-faults, a broad brittle shear zone is developed in the Ghadir two-mica granite. Brittle deformation is manifested by severe mylonitization and alteration of these granites. These sheared altered granites are characterized by the presence of radioactive mineralization, associated with alteration features such as silicification, hematization and kaolinitization.
Radioelement measurements revealed that the unaltered and altered two-mica granites are considered as uraniferous granites. The average uranium and thorium contents in the unaltered two-mica granites are 12.29×10−6 and 19.81×10−6, respectively, and the average Th/U ratio is 1.62. The altered granites exhibit higher concentrations of U (averaging 97.949), but have lower Th and Th/U ratios (13.83 and 0.16, respectively), which indicates uranium enrichment in the granites. Binary relations of eTh/eU against either eU or eTh and eU with eTh in the studied granites suggest that the distribution of radioactive elements not only magmatic (positive correlation between eU and eTh), but also due to hydrothermal redistribution of radioelements (weak correlation between eU and eTh/eU).
The magmatic U and Th are indicated by the presence of uraninite, thorite, zircon and monazite whereas the evidence of hydrothermal mineralization is the alteration of rock-forming minerals such as feldspar and the formation of secondary minerals such as uranophane and pyrite.
Microscopic, XRD and scanning electron microscopic studies revealed the presence of uraninite, uranophane, thorite, Ce-monazite and zircon, in addition to phlogopite-fluor mica in the studied altered granites of the Wadi Ghadir shear zone.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
Abu Dief A. (1985) Geology of Uranium Mineralization in Missikat, Qena-Safaga Road, Eastern Desert, Egypt [D]. pp.242. M.Sc. Thesis. Assiut University, Egypt (unpublished).
Assaf H.S., Mahdy M.A., and El Afandy A.H. (1997) Egyptian Younger Granites, an Approach to Define Parameters Favoring Formation of Uranium Deposits [M]. pp.409–420. 3rd Conference on Geochemistry, Alexandria University.
Assaf H.S., Shalaby M.H., Ibrahim M.E., and Rashed M.A. (1996) Ground Radiometric Survey, Shalatin-Halaib Area, Southeastern Desert, Egypt [R]. Internal Report, Nuclear Materials Authority, Egypt (unpublished).
Bea F. (1996) Residence of REE, Y, Th and U in granites and crustal protoliths, implications for the chemistry of crustal melts [J]. Journal of Petrology. 37, 521–552.
Cathelineau M. (1987) U-Th-REE mobility during albitization and quartz dissolution in granitoids: Evidence from southeast French Massif Central [J]. Bulletin Mineralogie. 110, 249–259.
Clark S.P.Jr., Peterman J.E., and Heier K.S. (1966) Abundance of uranium, thorium and potassium. In Handbook of Physical Contents (ed. Clark Jr. S.P.) [J]. Geol. Soc. Am. Mem. 97 (section 24), 521–541.
Cuney M. and Friedrich M. (1987) Physicochemical and crystal-chemical controls on accessory mineral paragenesis in granitoids: Implications for uranium metallogenesis [J]. Bulletin Mineralogie. 110, 235–247.
Cuney M., Le Fort P., and Wang Z.X. (1984) Uranium and thorium geochemistry and mineralogy in the Manaslu leucogranites (Himalaya, Nepal). In Geology of Granites and Their Metalogenic Relations [C]. pp.853–873. University Press, Beijing
Darnely A.G. (1982) “Hot granite”: Some general remarks. In: Uranium in Granites, Geological Survey of Canada (ed. Maurice Y.T.) [C]. pp.23–81, 1–10.
El-Feky M.G. (2000) Geology, Geochemistry and Radioactivity of Wadi Hangaliya Area, South Eastern Desert, Egypt [D]. pp.300. Ph.D Thesis. Cairo Univ., Egypt.
El-Galy M.M. (1998) Geology, Radioactivity, Geochemistry and Tectonic Setting of Selected Granitic Rocks, West Gulf of Aqaba, Sinai, Egypt [D]. pp.324. Ph.D Thesis. Tanta Univ., Egypt.
El-Sharkawy M.A. and El-Bayoumi R.M. (1979) The ophiolites of Wadi Ghadir area, Eastern Desert, Egypt [J]. Ann. Geol. Survey of Egypt. 9, 125–135.
Falkum T. and Rose-Hansen J. (1978) The application of radioelement studies in solving petrological problems of the Precambrian intrusive Homme granite in the Flekkefjord area, South Norway [J]. Chemical Geology. 23, 73–86.
Friedrich M. and Cuney M. (1989) Uranium Enrichment Processes in Peraluminous Magmatism [R]. pp.11–35. In Proceedings of IAEA meeting: Uranium Deposit in Magmatic and Metamorphic Rocks. Salamanca, Spain. IAEA-TC-571/2.
Forster H.J. (1998) The chemical composition of REE-Y-Th-U-rich accessory minerals in peraluminous granites of the Erzgebirge-Fichtelgebire region, Germany, Part I: The monazite-(Ce)-brabantite solid solution series [J]. American Mineralogist. 83, 259–272.
Gramaccioli C.M. and Segalstad T.V. (1978) A uranium- and thorium-rich monazite from a south-alpine pegmatite at Piona, Italy [J]. American Mineralogist. 63, 757–761.
Hinton R.W. and Paterson B.A. (1994) Crystallisation history of granitic magma: Evidence from trace element zoning [J]. Mineralogical Magazine. 58A, 416–417.
Hussein H.A. (1978) Lecture Course in Nuclear Geology [Z]. Ain Shams University (unpublished).
Ibrahim I.H. and Ali M.A. (2003) The granitic rocks in Wadi Ghadir area, South Eastern Desert, Egypt and occurrence of a secondary uranium mineral [J]. Egyptian Journal of Geology. 47(2), 671–687.
Ibrahim M.E., Saleh G.M., and Abd El-Naby H.H. (2001) Uranium mineralization in the two mica granite of Gabal Ribdab, South Eastern Desert, Egypt [J]. Appl. Radiat. Isot. 55(6), 123–134.
Ibrahim M.E. (1986) Geologic and Radiometric Studies on Um Ara Granite Pluton, South East Aswan, Egypt [D]. M.Sc. Thesis. Mansoura University, Egypt.
Jefferies N.L. (1985) The distribution of the rare earth elements within the Carnmenellis pluton, Cornwall [J]. Mineralogical Magazine. 49, 495–504.
Larsen E.S. and Gottfried D. (1960) Uranium and thorium in selected suites of igneous rocks [J]. Am. J. Sci. 258A, 151–169.
Mahdy A.I. (1998) Petrological and Geochemical Studies on the Younger Granites and Hammamat Sediments at Gattar-5, Uranium Occurrence, Wadi Balih, North Eastern Desert, Egypt [D]. pp.185. Ph. D. Thesis. Ain Shams Univ., Egypt.
Matolin M.M. (1991) “Construction and Use of Spectrometric Calibration Pads”, Laboratory of Gamma-ray Spectrometry, N.M.A., Egypt [R]. A report to the Government of the Arab Republic of Egypt. Project Egy. 4, 030-03, IAEA.
Montel J.M. (1986) Experimental determination of the solubility of Ce-monazite in SiO2-Al2O3-K2O-Na2O meets at 800°C, 2 kbar, under H2O-saturated conditions [J]. Geology. 14, 659–662.
Raslan M.F. (2004) On the Distinction Between Uranophane and Beta-uranophane from Some Uraniferous Granitoids in the Eastern Desert of Egypt [C]. pp.45–52. In Seventh International Conference on the Geology of the Arab World, Cairo University.
Raslan M.F. (2009) Occurrence of uraniferous iron grains at Gabal Gattar, El Missikat and El Erediya granites in Eastern Desert of Egypt [J]. Resource Geology. 59(1), 99–105.
Reeves R.D. and Brooks R.R. (1978) Trace Element Analyses of Geological Materials [M]. pp.421. John Wiley & Sons Inc., New York.
Rogers J.J.W. and Adams J.A.S. (1969) Uranium and thorium. In Handbook of Geochemistry (ed. Wedepohl K.H.) [C]. VII-3, 92-B-1 to 92-0-8, 90-B-1 to 90-0-5. Springer Verlag, Berlin.
Rogers J.J.W. and Rangland P.C. (1961) Variation of thorium and uranium in selected granitic rocks [J]. Geochim. et Cosmochim. Acta. 25, 99.
Roz M.E. (1994) Geology and Uranium Mineralization of Gabal Gattar Area, North Eastern Desert, Egypt [D]. pp.175. M.Sc. Thesis. Al Azhar Univ., Egypt (unpublished).
Sabet A.H., Tosogoev V.B., Bessonenko V.V., Baburin I.M., and Pokryshkin V.I. (1978) Some geological and tectonic peculiarities of the Central Eastern Desert of Egypt [J] Geol. Surv. Egypt. 6, 33–52.
Surour A.A., El-Bayoumi R.M., Attawiya M.Y., and El-Feky M.G. (2001) Geochemistry of wall rock alterations and radioactive mineralization in the vicinity of Hangaliya auriferous shear zone, Eastern Desert, Egypt [J]. Egyptian Journal of Geology. 45(1), 187–212.
Takla M.A., Basta F.F., Shenouda H.H., and El-Maghraby A.M. (1992) Geochemistry of geneisses and granitoids of Wadi Ghadir area, Eastern Desert, Egypt [J]. GAW. Cairo Univ. I, 477–489.
Whitfield J.M., Rogers J.J.W., and Adams J.A.S. (1959) [J].Geochimica et Cosmochimica Acta. 17, 248–271.
Yanting W., Mingyue F., and Zhuyong S. (1982) Uranium Geochemistry of the Granites in Eastern Guangdong Province [C]. pp.637–649. International symposium held at Nanjing.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Raslan, M.F., El-Feky, M.G. Radioactivity and mineralogy of the altered granites of the Wadi Ghadir shear zone, South Eastern Desert, Egypt. Chin. J. Geochem. 31, 30–40 (2012). https://doi.org/10.1007/s11631-012-0546-6
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11631-012-0546-6