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Authigenic halloysite from El-Gideda iron ore, Bahria Oasis, Egypt: characterization and origin

Published online by Cambridge University Press:  09 July 2018

H. M. Baioumy  and
M. S. Hassan
H. M. Baioumy*
Affiliation:
Central Metallurgical R and D Institute, P.O. Box 87, Helwan, Cairo, Egypt
M. S. Hassan
Affiliation:
Central Metallurgical R and D Institute, P.O. Box 87, Helwan, Cairo, Egypt
*
*E-mail: [email protected]
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Abstract

Halloysite in El-Gideda iron mine occurs as very soft, light and white-to-pinkish white pockets and lenses ranging in diameter from 50 cm to 1 m within the iron ore. Highly hydrated halloysite is the main constituent of these pockets beside some kaolinite and alunite. The diffraction pattern of the clay fraction (<2 mm) shows a rather broad and diffuse 001 reflection spread between 10.3 and 13.6°2θ. Upon treatment, the 001 reflection of halloysite expands up to 10.94 Å and 11.9 Å corresponding to ethylene glycol and dimethyl formamide treatment, respectively. After these treatments, kaolinite appeared with its characteristic basal spacing (~7 Å). The percentage of halloysite in halloysite-intercalated kaolinite ranged between 80 and 90%. Heating to 350°C, produces a kaolinite-like structure (~7.1 Å) that developed to a metakaolinite-structure when heated to 550°C. Morphologically, halloysite appears as well developed tubes composed entirely of SiO2 and Al2O3, while kaolinite is characterized by very fine platelets arranged in book-like or rosette-like shapes. A differential thermal analysis curve of the studied halloysite showed an endothermic peak at ~138°C due to the dehydration of interlayer water of halloysite. The small shoulder at ~540°C and the endothermic peak at ~593°C is attributed to the dehydroxylation of halloysite, kaolinite and alunite. On the other hand the exothermic peak that appeared at 995°C is due to the formation of new phases such as mullite and/or spinel. The infrared vibrational spectrum is typical of highly disordered halloysite and kaolinite.

Halloysite was formed as a result of alteration of the overlying glauconite suggesting intensive chemical alteration during a humid wet period that prevailed in the Bahria Oasis during the late Eocene. Glauconite alteration releases K, Fe, silica and alumina. Iron forms at least part of the iron ore in the El-Gideda mine while alumina forms halloysite as well as alunite when interacted with silica in an acidic environment.

Keywords

El-GidedaBahria OasisEgypthalloysitekaolinitealuniteglauconitealterationiron
Type
Research Article
Information
Clay Minerals , Volume 39 , Issue 2 , June 2004 , pp. 207 - 217
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2004

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References

Abdel-Monem, A.M., Qorani, E.A. & Youssef, A.M. (2003) Occurrence and genesis of pyrite in El- Gideda iron mine, El-Bahria depression, Western Desert, Egypt. Sedimentology of Egypt, 11, 227–233.Google Scholar
Al-Boghdady, A.A. & Abu El-Hassan, M.M. (1999) Nature of occurrence and origin of the Barite at El- Gideda iron ore mines, Bahria Oasis, Egypt. Geochemistry International, 5, 536–548.Google Scholar
Bailey, S.W. (1989) Halloysite–a critical assessment: Proceedings of the 9th International Clay Conference, Strasbourg, pp. 89–98.Google Scholar
Brindley, G.W. (1980) Order-disorder in clay mineral structures: Pp. 125–195 in: Crystal Structures of Clay Minerals and their X-ray Identification (Brindley, G.W. and Brown, G., editors). Monograph 5, Mineralogical Society, London.Google Scholar
Chukhrov, F.V. & Zvyagin, B.B. (1966) Halloysite, a crystallochemically and mineralogically distinct species. Proceedings of the International Clay Conference, Jerusalem, pp. 11–25.Google Scholar
Churchman, G.J., Whitton, J.S. & Claridge, GGC. & Theng, B.K.G (1984) Intercalation method using formamide for differentiating halloysite from kaolinite. Clays and Clay Minerals, 32, 241–248.Google Scholar
El-Aref, M.M. & Lotfy, Z.H. (1987) Genetic karst significance of the iron ore deposits of Bahria Oasis, Western Desert, Egypt. Annals of the Geological Survey of Egypt, 15, 1 –30.Google Scholar
El-Aref, M.M., El-Sharkawi, M.A. & Khalil, M.A. (1999) The geology and genesis of the stratabound to stratiform Cretaceous-Eocene ore deposits of Bahria Region, Western Desert, Egypt. International Conference on the Geology of the Arab World, Cairo University, Egypt, pp. 450–475.Google Scholar
El-Sharkawi, M.A & Khalil, M.A. (1977) Glauconite, a possible source of iron for El-Gideda iron ore deposits, Bahria Oases, Egypt. Egyptian Journal of Geology, 21, 109–116.Google Scholar
Giese, R.F. Jr. (1988) Interlayer bonding in kaolinite, dickite and nacrite. Clays and Clay Minerals, 21, 145–149.Google Scholar
Hashimoto, I. & Jackson, M.I. (1960) Rapid dissolution of allophane and kaolinite-halloysite after dehydration. Proceedings of the 7th International Clay Conference, Oxford. Pergamon Press, Oxford, UK.Google Scholar
Hill, C.A. (2000) Overview of geologic history of cave development in the Guadalipe Mountains. Journal of Cave and Karst Studies, 62, 60–71.Google Scholar
Mesaed, A.A. (1990) Geological and mineralogical studies on the ferruginous sediments of El-Heiz area, Bahria Oasis, Western Desert, Egypt. M.Sc. thesis, Cairo University, 235 pp.Google Scholar
Mesaed, A.A. & Suror, A.A. (1999) Mineralogy and geochemistry of the Bartonian stratabound diagenetic and lateritic glauconitic ironstones of El-Gedida Mine, Bahria Oasis, Egypt. International Conference on the Geology of the Arab World, Cairo University, Egypt, pp. 509–540.Google Scholar
Moore, M.D. & Reynolds, R.C. Jr. (1989) X-ray Diffraction and the Identification and Analysis of Clay Minerals. Oxford University Press, Oxford, New York, 332 pp.Google Scholar
Noro, H. (1986) Hexagonal platy halloysite in an altered tuff bed, Komaki City, Aichi Prefecture Central Japan. Clay Minerals, 21, 401–415.Google Scholar
Polyak, V.J. & Güven, N. (1996) Alunite, natroalunite and hydrated halloysite in Carlsbad Cavern and Lechuguilla Cave, New Mexico. Clays and Clay Minerals, 44, 843–850.Google Scholar
Polyak, V.J., McIntosh, W.C., Güven, N. & Provenio, P. (1998) Age and origin of Carlsbad Cavern and related caves from 40Ar/39Ar of alunite. Science, 279, 1919–1922.Google Scholar
Polyak, V.J. & Güven, N. (2000) Clays in caves of the Guadalupe Mountains, New Mexico. Journal of Cave and Karst Studies, 62, 120–126.Google Scholar
Robertson, I.D.M. & Eggleton, R.A. (1991) Weathering of granitic muscovite to kaolinite and halloysite and of plagioclase-derived kaolinite to halloysite. Clays and Clay Minerals, 39, 113–126.CrossRefGoogle Scholar
Romero, R., Robert, M., Elsans, F. & Garcia, C. (1992) Abundance of halloysite neoformation in soils developed from crystalline rocks. Contribution of transmission electron microscopy. Clay Minerals, 27, 35–46.Google Scholar
Sehim, A.A. (1993) Cretaceous tectonics in Egypt. Journal of Geology, 37, 335–372.Google Scholar
Sudo, T. & Yotsumoto, H. (1977) The formation of halloysite tubes from spherulitic halloysite. Clays and Clay Minerals, 25, 155–159.Google Scholar
Tazaki, K. (1982) Analytical electron microscopic studies of halloysite formation processes, morphology and composition of halloysite. Proceedings of the International Clay Conference, Pavia, Bolonga, Italy, pp. 573–584.Google Scholar
Tomura, S., Shibasaki, Y. & Mizuta, H. (1985) Growth, conditions and genesis of spherical and platy halloysite. Clay Minerals, 33, 200–206.Google Scholar
Vaughan, R.G., Calvin, W.M., Hook, S.J. & Taranik, J.V. (2002) Mapping acid sulfate alteration of basaltic andesite with thermal infrared data. Lunar and Planetary Science, XXXIII, 1153–1154.Google Scholar
Wilson, M.J. (1999) The origin and formation of clay minerals in soils: past, present and future perspectives. Clay Minerals, 34, 7–25.CrossRefGoogle Scholar
Wolf, R.G. (1967) X-ray and chemical study of weathering glauconite. American Mineralogist, 52, 1129–1138.Google Scholar