Hostname: page-component-cd9895bd7-jn8rn Total loading time: 0 Render date: 2024-12-27T08:32:46.688Z Has data issue: false hasContentIssue false
  • English
  • Français

Chemistry of columbite-tantalite minerals in rare metal granitoids, Eastern Desert, Egypt

Published online by Cambridge University Press:  05 July 2018

H. M. Abdalla ,
H. A. Helba  and
F. H. Mohamed
H. M. Abdalla
Affiliation:
Nuclear Materials Authority, Cairo, Egypt
H. A. Helba
Affiliation:
Geology Department, Alexandria University, Alexandria, Egypt
F. H. Mohamed
Affiliation:
Geology Department, Alexandria University, Alexandria, Egypt
Get access Rights & Permissions [Opens in a new window]

Abstract

Paragenetic, textural, and chemical characteristics of columbite-tantalite minerals are examined as steps towards identifying the metallogenetic processes of their host granitoids. Columbite-tantalite-bearing granitoids of the Eastern Desert province of Egypt can be categorized into: (i) metaluminous alkali granites; (ii) peraluminous Li-albite granites; and (iii) metasomatized biotite and/or muscovite granite (i.e. apogranites).

Columbite of the alkali granite is of FeNb2O6 composition and associated with annite. The low F and Li contents of the associated mica precludes the important role of these volatile elements during the late stage of evolution of the alkali granites, thus delaying fractionation of Mn over Fe and Ta over Nb.

Compositionally, columbite-tantalite of the Li-albite granites is constrained between MnNb2O6 and MnTa2O6 (the Ta/(Nb+Ta)atom. ratio ranges between 0.10 and 0.80). This low to high ratio and the association of columbite-tantalite with topaz, fluorite and lithian micas (in the series zinnwaldite-white mica) indicate a higher solubility for Ta-fluoride complex compounds and their more stabilized state at lower temperatures in Li- and F-rich sodic melts. The columbite-tantalite commonly exhibits a mottled or patchy zoned texture with the rims consistently higher in Ta than the cores, reflecting the later effect of a corrosive supercritical vapour phase.

The columbites of metasomatized granites range in composition between FeNb2O6 and MnNb2O6. They are characterized by high Ti and U, and low Ta contents (the Ta/(Nb+Ta)atom. ranges between 0.01 and 0.15), indicating deposition from alkaline (K+ Na+ -rich), and relatively high-temperature interacting fluids. However, the Mn-enriched columbites are commonly encountered in the apical parts of the apogranites and formed in response to high μKF and μLiF required for stabilizing the associated Li-siderophyllite or zinnwaldite. Columbites of the apogranites commonly exhibit progressive (either normal or reverse) zoning which can be attributed to the disequilibrium conditions (e.g. sudden change in the pH) between the growing crystal and the solutions.

Keywords

columbitetantalitegranitoidsEastern DesertEgypt
Type
Research Article
Information
Mineralogical Magazine , Volume 62 , Issue 6 , December 1998 , pp. 821 - 836
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1998

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Abdalla, H.M. and Helba, H. (in prep.) Petrographical and geochemical characterization of Sn, Nb, and Ta-bearing granitoids, Eastern Desert, Egypt: 1- Metallogenetic and exploration aspects.Google Scholar
Abdalla, H.M., Matsueda, H., Ishihara, S. and Miura, H. (1994) Mineral chemistry of albite-enriched granitoids at Um Ara, Southeastern Desert, Egypt. Internat. Geol. Rev., 36, 1067–77.CrossRefGoogle Scholar
Abdalla, H.M., Ishihara, S., Matsueda, H. and Abdel-Monem, A.A. (1996) On the albite-enriched granitoids at Um Ara area, Southeastern Desert, Egypt. I) Geochemical, ore potentiality and fluid inclusion studies. J. Geochem. Explor., 58, 127–38.CrossRefGoogle Scholar
Alexandrov, I.V., Krasov, A.M. and Kochnova, L.N. (1985) The effects of K, Na and F on rock-forming mineral assemblages and the formation of tantaloniobate mineralisation in rare-element granite pegmatites. Geochem. Internat., 22, 85–92.Google Scholar
Beus, A.A. and Zalashkova, N.Ye. (1964) Postmagmatic high temperature metasomatic processes in granitic rocks. Internat. Geol. Rev., 6, 668–81.CrossRefGoogle Scholar
Beus, A.A., Severov, E.A., Sitnin, A.A. and Subbotin, K.D. (1962) Albitized and Greisenized Granites (apogranites). Academy Science Press, Moscow. 196 pp. (In Russian).Google Scholar
Černý, P. (1991) Fertile granites of Precambrian rare-element pegmatite fields: is geochemistry controlled by tectonic setting or source lithologies?. Precamb. Res., 51, 429–68.CrossRefGoogle Scholar
Černý, P. and Ercit, T.S. (1985) Some recent advances in the mineralogy and geochemistry of Nb and Ta in rare-element granitic pegmatites. Bull. Mineral., 108, 499–532.Google Scholar
Černý, P. and Ercit, T.S. (1989) Mineralogy of niobium and tantalum: crystal chemical relationships, paragenetic aspects and their economic implications. In Lanthanides, Tantalum and Niobium (Moller., P. Černý, P. and Saupe, F., eds.), pp. 27–79. Springer, Berlin.CrossRefGoogle Scholar
Černý, P. and Nemec, D. (1995) Pristine vs. contaminated trends in Nb, Ta-oxide minerals of the Jihlava pegmatite district, Czech Republic. Mineral. Petrol., 55, 117–29.CrossRefGoogle Scholar
Černý, P., Goad, B.E., Hawthorne, F.C. and Chapman, R. (1986) Fractionation trends of the Nb-and Ta-bearing oxide minerals in the Greer Lake pegmatitic granite and its pegmatite aureole, Southern Manitoba. Amer. Mineral., 71, 501–17.Google Scholar
Černý, P., Meintzer, R.E. and Anderson, A.J. (1985 a) Extreme fractionation in rare-element granitic pegmatites: selected examples of data and mechanisms. Canad. Mineral., 23, 381–421.Google Scholar
Černý, P., Roberts, W.L., Ercit, T.S. and Chapman, R. (1985 b) Wodginite and associated minerals from the Peerless pegmatite, Pennington County, South Dakota. Amer. Mineral., 70, 1044–9.Google Scholar
Christiansen, E.H., Sheridan, M.F. and Burt, D.M. (1986) The geology and geochemistry of Cenozoic topaz rhyolites from the western United States. Geol. Soc. Amer., Spec. Pap., 205, 82 pp.Google Scholar
Cuney, M., Autran, A. and Burnol, L. (1985) Premiers resultats par le sondage GPF de 900 m realise sur le granite sodo-lithique et fluore a mineralisation disseminee de Beauvoir. Chron. Rech. Mineral., 481, 59–63.Google Scholar
De Kun, N. (1962) The economic geology of columbium (niobium) and tantalum. Econ. Geol., 54, 377–404.CrossRefGoogle Scholar
Garson, M.S. and Krs, M. (1976) Geophysical and geological evidence of the relationship of Red Sea traverse tectonics to ancient fractures. Bull. Geol. Soc. Amer., 87, 169–81.2.0.CO;2>CrossRefGoogle Scholar
Geological Map of Egypt. (1978) Egypt. Geol. Surv., Cairo.Google Scholar
Hannah, J.L. and Stein, H.J. (1990) Magmatic and hydrothermal processes in ore-bearing systems. In Ore-bearing Granite Systems; Petrogenesis and Mineralizing Processes (Stein, H. and Hannah, J., eds). Geol. Soc. Amer. Spec. Paper. pp. 1–11.Google Scholar
Hassan, M.A. and Hashad, A. (1990) Precambrian of Egypt. In The Geology of Egypt (Said, R., ed.). A. A. Balkema-Rotterdam and Brookfield Pub. pp. 201–45.Google Scholar
Heinrich, E.Wm. (1962) Radioactive columbite. Amer. Mineral., 47, 1363–79.Google Scholar
Helba, H. (1994) Geochemical prospecting in Nuweibi area, Eastern Desert, Egypt. PhD. Thesis, Fac. Sci., Alexandria University. 156 pp.Google Scholar
Helba, H., Trumbull, R.B., Morteani, G., Khalil, S.O. and Arslan, A. (1997) Geochemical and petrographical studies of Ta mineralization in the Nuweibi albite granite complex, Eastern Desert, Egypt. Mineral. Deposita, 32, 164–79.CrossRefGoogle Scholar
Hildreth, W. (1979) The Bishop Tuff: evidence for the origin of compositional zonation in silicic magma chambers. Geol. Soc. Amer., Spec. Pap., 180, 43–75.Google Scholar
Hildreth, W. (1981) Gradients in silicic magma chambers: Implications for lithospheric magmatism. J. Geophys. Res., 86, 10153–92.CrossRefGoogle Scholar
Hu, S., Sun, M., Yan, Z., Xu, J., Cao, X. and Ye, Y. (1984) An important metallogenetic model for W, Sn and rare granitophile element ore deposits related to metasomatically altered granites. In Geology of Granites and their Metallogenetic Relations(Keqin, X. and Guangchi, T., eds. ), Science Press, Beijing, pp. 519–37.Google Scholar
Kanisawa, S. (1978) Fluorine determination in silicate rocks using a specific ion electrode. J. Japan. Assoc. Mineral. Petrol. Econ. Geol., 73, 26–9.CrossRefGoogle Scholar
Keppler, H. (1993) Influence of fluorine on the enrichment of high field strength trace elements in granitic rocks. Contrib. Mineral. Petrol., 114, 479–88.CrossRefGoogle Scholar
Kovalenko, V.I. and Kovalenko, N.I. (1984) Problems of the origin, ore-bearing and evolution of rare-metal granites. Physics Earth Planet. Interiors, 35, 51–62.CrossRefGoogle Scholar
Kovalenko, V.I., Kuzmin, M.I., Antipin, V.S. and Petrov, L.L. (1971) Topaz-bearing keratophyre (ongonite), a new variety of subvolcanic igneous vein rock. Dokl. Acad. Sci. USSR Earth Sci. Sect., 199, 132–5.Google Scholar
Lahti, S.I. (1987) Zoning in columbite-tantalite crystals from the granitic pegmatites of the Erajarvi area, Southern Finland. Geochim. Cosmochim. Acta, 51, 509–17.CrossRefGoogle Scholar
Mackenzie, D.E., Black, L.P. and Sun, S. (1988) Origin of alkali-feldspar granites: an example from the Poimena, northe astern Tasmania, Australia. Geochim. Cosmochim. Acta, 52, 2507–24.CrossRefGoogle Scholar
Manning, D.A.C. (1981) The effect of fluorine on liquidus phase relationships in the system Qz-Ab-Or with exess water at 1 kb. Contrib. Mineral. Petrol., 76, 206–15.CrossRefGoogle Scholar
Martin, J.S. (1983) An experimental study of the effects of lithium on the granite system. Proc. Ussher Soc., 5, 417–20.Google Scholar
Mason, B. (1963) Principles of Geochemistry. John Wiley and Sons. New York.Google Scholar
Mohamed, F.H. (1989) Geochemical prospecting in Nugrus area, Southern Eastern Desert, Egypt. PhD. Thesis, Alexandria Univ., 200 pp.Google Scholar
Mohamed, F.H. (1993) Rare metal-bearing and barren granites, Eastern Desert of Egypt: geochemical characterization and metallogenetic aspects. J. Afr. Earth Sci., 17, 525–39.CrossRefGoogle Scholar
Mohamed, F.H. and Abdalla, H.M. (in prep.) Chemistry of micas of rare metal granitoids and associating rocks, Eastern Desert, Egypt.Google Scholar
Mohamed, F.H. and Kanisawa, S. (in press) The Pan-African intrusive complex of Ghorabat area, Southern Egypt: geochemical and mineralogical constraints on arc-related and anorogenic magmatism. Chemie der Erde. Google Scholar
Morsey, M.A. and Mohamed, F.H. (1992) Geochemical chracteristics and petrogenetic aspects of Muelha tinspecialized granite, Eastern Desert, Egypt. Bull. Fac. Sci., Alexandria University, 32A, 502–15.Google Scholar
Neiva, A.M.R. (1996) Geochemistry of cassiterite and its inclusions and exsolution products from tin and tungsten deposits in Portugal. Canad. Mineral., 34, 745–68.Google Scholar
Pichavant, M. (1983) (Na, K) exchange between alkali feldspars and aqueous solutions containing borate and fluoride anions, experimental results at p=1 kbar. 3rd NATO Adv. Stu. Inst. Feldspars and feldspathoids Rennes, 102 pp.Google Scholar
Pitcher, W.S. (1983) Granite: typology, geological environment and melting relationships. In Migmatites, Melting and Metamorphism (Atherton, M.P. and Gribble, C.D., eds), Shiva Publishing, UK, pp. 277–85.Google Scholar
Pollard, P.J. (1983) Magmatic and postmagmatic processes in the formation of rocks associated with rare-element deposits. Trans. Inst. Min. Metall. (Section B, Applied Earth Science), 92, 1–9.Google Scholar
Pollard, P.J. (1989) Geochemistry of granites associated with tantalum and niobium mineralization. In Lanthanides, Tantalum and Niobium (Moller, P.,Černý, P. and Saupe, F., eds), Springer, Berlin, pp. 145–68.CrossRefGoogle Scholar
Raimbault, L., Charoy, B., Cuney, M. and Pollard, P. (1991) Comparative geochemistry of Ta-bearing granites. In Source, Transport and Deposition of Metals (Pagel, M. andLeroy, J., eds), Balkema, Rotterdam, pp. 793–6.Google Scholar
Schwartz, M.O. (1992) Geochemical criteria for distinguishing magmatic and metasomatic albiteenrichment in granitoids-examples from the Ta-Li granite Yichun (China) and the Sn-W deposit Tikus (Indonesia). Mineral. Deposita, 27, 101–8.CrossRefGoogle Scholar
Smirnov, V.I., Ginzburg, A.I., Grigoriev, V.M. and Yakovlev, G.F. (1983) Studies of Mineral Deposits. Mir Pub., Moscow.Google Scholar
Tischendorf, G. (1977) Geochemical and petrographic characteristics of silicic magmatic rocks associated with rare-element mineralization. In Metallization Associated with Acid Magmatism (Stemprok, M., Burnol, L. and Tischendorf, G., eds). Czechoslovakia Geol. Surv., Prague, pp. 41–98.Google Scholar
von Knorring, O. and Fadipe, A. (1981) On the mineralogy and geochemistry of niobium and tantalum in some granite pegmatites and alkali granites of Africa. Bull. Mineral., 104, 496–507.Google Scholar
von Knorring, O. and Condliffe, E. (1984) On the occurrence of niobium, tantalum, and other rare element minerals in Meldon aplite, Devonshire. Mineral. Mag., 48, 443–8.CrossRefGoogle Scholar
Wang, Y., Jitian, L. and Fan, W. (1982) Geochemical mechanism of Nb-Ta mineralization during the late stage of granite crystallizat ion. Geochemistry (Beijing), 1, 175–85.Google Scholar
Whalen, J.B., Currie, K.L. and Chappell, B.W. (1987) A-type granites: geochemical characteristics, discrimination and petrogenesis. Contrib. Mineral. Petrol., 95, 407–19.CrossRefGoogle Scholar