Ore Microscopy of the Pegmatites of Keffi Area, North Central Nigeria


  •   I. Y. Tanko

  •   K. Dzigbodi-Adjimah


Investigation of the pegmatites of Keffi area was carried out in reflected light microscopy to determine the texture, elemental composition, and the semi-quantitative analysis of the ore minerals from the three groups of pegmatites identified in Keffi area: the non-mineralised, the intermediate and the mineralised pegmatites. Backscattered Electron (BSE) images and Wavelength Dispersive Spectrometry (WDS) were used. Petrographically the portion which is characterised by profuse albitisation, sericitisation and silicification is also associated with the development of cleavelandite, lepidolite, coloured tourmaline and high concentrations of cassiterite and columbite-tantalite (coltan).The order of crystallisation in the pegmatites is from microcline to quartz followed by (plagioclases) oligoclase to albite and by mica (from biotite to muscovite) then by accessory minerals such as black tourmaline, garnet, beryl and lastly oxides of Sn-Nb-Ta. Sphene, rutile, zircon, apatite, ilmenite, and magnetite appeared to be earliest minerals whilst garnet pyrite and chalcopyrite may be syn-metamorphic. Beryl and coloured tourmaline appear to be of hydrothermal phase.

Keywords: Microscopy, mineralization, Ore, Pegmatites


R. Jacobson and J. S. Webb, “The Pegmatite of Central Nigeria”, Geological Survey of Nigeria Bulletin, Vol. 17, pp. 61, 1946.

D. Kuster “Rare-Metal Pegmatites of Wamba, Central Nigeria-their Formation in Relationship to Late Pan-African Granites”, Mineral Deposita, Vol. 25, pp. 25-33, 1990.

A. I., Ginsburg, I. N. Timofeyev, and L. G. Feldman, Principles of Geology of the Granitic Pegmatites, Nedra, Moscow, Russia, pp. 296, 1979.

P. Cerny Petrogenesis of Granitic Pegmatites, In Mineralogical Association of Canada, Short Course Handbook, No. 8, Granitic Pegmatites in Science and Industry, 1982, pp. 405-461.

R. A., Crouse, P. Cerny, D. L. Trueman, and R. O. Burt, “The Tanco Pegmatite, Southeastern Manitoba”, In CIM Special, Vol. 29, The Geology of Industrial Minerals in Canada, pp. 169-176, 1984.

G. B. Morgan VI., D. London, “Alteration of Amphibolitic Wall rocks Aroundthe Tanco Rare-Element Pegmatite”, Bernic Lake Manitoba, Am. Mineral., Vol. 72, pp. 1097-1121, 1987.

P. Cerny, “Rare-Element Granitc Pegmatites, Part I: Anatomy and Internal Evolution of Pegmatite Deposits”, Geoscience Can., Vol. 18, pp. 49-67, 1991.

D. London, “The Application of Experimental Petrology to the Genesis and Crystallisation of Granitic Pegmatites”, Can. Mineral, Vol. 30, pp. 499-540, 1992.

P. Cerny and T. S. Ercit and P. T Vanstone, “Petrology and Mineralisation of the Tanco Rare-Element Pegmatite, South-eastern Manitoba-Field Trip Guidebook A4, Geol. Ass. Can. Annual Meeting, Winnipeg Manitoba, 63 pp, 1996.

R. Black. “Precambrian of West Africa”, Episodes, No. 4, pp. 3, 1980,

H. A. Jones, and R. D. Hockey (1964), “The Geology of Part of South Western Nigeria”, Geol. Surv. Nigeria Bull. No. 31, pp. 101, 1980.

M. A. Rahaman, “Review of Basement Geology of Southern Nigeria, In Kogbe”, C. A. (Eds.), Geol. Nigeria Elizabethan press, Lagos, Nigeria, 1976, pp. 41-58.

A. C. Ajibade, M. Woakes, and M. A. Rahaman, “Proterozoic Crustal Development in the Pan-African Regime of Nigeria”, In C. A. Kogbe (Eds.), Geol. Nigeria, 2nd Revised Eds., Elizabethan Publ., Lagos, 1989, pp. 57-69.

S. S. Dada, “Proterozoic Evolution of Nigeria”, In: The Basement Complex of Nigeria and its Mineral Resources (Oshin O. ed.), A Symposium organized to mark the 60th birthday of Prof. M. A. O. Rahaman, held at the Conference Centre, Obafemi Awolowo University, Ile – Ife, Nigeria, May 6th 2006, pp. 29-44.

K. C. Burke and J. F. Dewey, “Orogeny in Africa.” In: Dessauvagie, T.F.J. and Whiteman, A. J. (Eds.), African Geology, University of Ibadan Press, Ibadan, 1972, pp. 583-608.

R., Caby, J. M. L Brand and R Black, Pan-African Ocean Closure and continental Collision in the Hoggar Iforas Segment, Central Sahara”, in Precambrian Tectonics”, Edited by a Kroner, Elsevier Amsterdam, 1981, pp. 407-434.

P. McCurry, “The Geology of the Precambrian to Lower Paleozoic Rocks of Northern Nigeria - A Review”, Geology of Nigeria., Elizabethan Publ. Co., Lagos, 1976, pp.15-40.

J. B. Wright, “Fracture Systems in Nigeria and Initiation of Fracture Zones in the South Atlantic”, Tectonophysics, Vol. 34, pp. 743-747, 1976.

M. A. Rahaman, “Recent Advances in the Study of the Basement Complex of Nigeria”, Precambrian Geol. Nigeria, Geol. Surv. Nig. Pub., 1988, pp. 324-327.

E. Ferre, R., Caby, J. J., Peucatt, R Capdevila, and P. Monie, Pan-Africa post collisional ferro-potassic granite and quartz-monzonite plutons of Eastern Nigeria. Lithos, 45, pp. 255-278, 1998.

A. O. Oyinloye, Geology and Geotectonic Setting of the Basement Complex rocks in southwestern Nigeria: Implications on Provenance and Evolution.Earth and Environmental Sciences, pp. 45-78, 2011.

B. N. Ekwueme, ’Regional metamorphism of pelitic rocks, south-east of Lokoja, Nigeria.Nigerian journal of Min. Geol. Vol. 20, pp. 17-24, 1983.

J. A. Kinnaird, “Contrasting Styles of Sn-Nb-Ta-Zn Mineralisation in Nigeria” Journal of African Earth. Science Vol. 2, No. 2, pp. 81-90, 1984.

I.Y. Tanko, M. Adam and P.D. Dambring, “Field Features and Mode of Emplacement of Pegmatites of Keffi Area, North Central Nigeria”. International Journal of Scientific & Technology Research Vol. 4, pp. 214-229, 2015.


How to Cite
Tanko, I. Y., & Dzigbodi-Adjimah, K. (2021). Ore Microscopy of the Pegmatites of Keffi Area, North Central Nigeria. European Journal of Environment and Earth Sciences, 2(5), 34-40. https://doi.org/10.24018/ejgeo.2021.2.5.174