ABSTRACT
We have conducted the geological mapping of the region surrounding Ganaja in Lokoja Local Government Area of Kogi State. We identified five (5) predominant rock units: Augen gneiss, porphyritic granite, biotite gneiss, granite gneiss, and migmatitic gneiss. The minor rocks comprise quartzo-feldsparic intrusion and quartz vein. The region features several geological structures, including folds, fractures (faults, folds, and joints), and foliation, oriented in NW-SE and NE-SW directions, attributed to the imprints of the Pan-African Orogeny. The petrographic investigation indicates that the five rock types are of granitic origin, according to their elevated quartz and feldspar concentrations. The primary mineral constituents include quartz, plagioclase, microcline, biotite, and amphibole. SiO2 makes up 68.859% of the oxides, followed by Al2O3 at 12.706%, CaO at 5.747%, Na2O at 3.339%, K2O at 3.623 %, MgO at 2.864%, Fe2O3 at 1.779%, TiO2 at 0.294 %, MnO at 0.329 %, and P2O5 at 0.461 %. The results indicate that the rocks are calcic and exhibit high K-Calc alkaline characteristics. Except for sample L2, which is located in the sedimentary field, the majority of the rocks are located in the eugeosynclinal field. The majority of the rocks are classified as S-type peraluminous, with the exception of SA and L6, which are classified as theolithic and I-type peraluminous, respectively. They all plot in the granodioritic field.
References
[1] Akindele O. Oyinloye (2011): Geology and Geotectonic Setting of the Basement Complex Rock in South Western Nigeria: Implications on Provenance and Evolution, Earth and Environmental Sciences, Dr. Imran Ahmad Dar (Ed.), ISBN: 978-953-307-468-9.
[2] Onimisi M., Obaje N.G, and Daniel A. (2013). Field geologic occurrence and petrographic characteristics of Precambrian marble body in Itobe area, Central Nigeria. Advances in Applied Science Research. 4(5):58-71.
[3] Folorunsho, A.F., Ayolabi E.A., and Ariyo S.O. (2013): Geological mapping, petrology study and structural analysis of Precambrian basement complex rocks in part of Ago-Iwoye outhwestern Nigeria. (IRJGM (2276-6618) Vol. 3(1): 19-30.
[4] Olatunji J.A., Imasuen O.I., and Onyeobi T. (2013): Geological observations of basement rocks, around Ganaja, Kogi State, Nigeria. International Research Journal of Geology and Mining (IRJGM) 3(2):57-66.
[5] Adegbuyi, O., Ogunyele, A.C., and Akinyemi, O.M. (2018): Petrology and Geochemistry of Basement Gneissic Rocks around Oka-Akoko, Southwestern Nigeria. Malaysian Journal of Geosciences, 2(2):11-16.
[6] Gideon, Y.B., (2019): Petrography and Geochemical characterization of Basement rocks within Okene metropolis, North Central Nigeria. International Journal of Geology, Earth & Environmental Sciences. 9 (2):36-48.
[7] Adamu, L.M., Umaru, A.O., Aliyu, A.E., Ereosun, T.S., and Kitha, M. (2021): Geology, Geochemistry and Petrogenetic Studies of the Precambrian Basement Rocks around Jimgbe, North-central Nigeria, Journal of Mining and Geology, 57(2), 229-240.
[8] Adamu, L. M., Lekdukun, M.O., Adesina, D.A., Emmanuel, A.U., Ibrah, S.O. and Adamu, N. (2024): Geology, Petrology and Geochemistry of the Basement Rocks around Ihima, Southwestern Basement Complex, Nigeria. World Scientific News, 190(2):70-100.
[9] Ajibade, A.C, and Fitches, W.R. (1988): The Nigerian Precambrian and the Pan – African Orogeny, Precambrian Geology of Nigeria, 45-53.
[10] Rahaman, M.A (1988): Recent advances in the study of the basement complex of Nigeria.
Symposium on the Geology of Nigeria, Obafemi Awolowo University, Nigeria.
[11] Obaje, N.G. (2009): Geology and Mineral Resources of Nigeria (221 p) Berlin: Springer
[12] Rahaman M. A. (1973). The geology of the District around Iseyin, Western State, Nigeria. Ph.D. thesis, University Of Ibadan, pp 268
[13] Jones, H. A. & tlockey, R. D. 1964. Geology of parts of southwestern Nigeria. Bulletin of the Geological Survey of Nigeffa 41, 101 pp.
[14] Rahaman, M. A. (1981). Recent advances in the study of the Basement Complex of Nigeria. Abstract, 1 1st Symposium in the Precambrian Geology of Nigeria.
[15] McCurry, P. (1976). The geology of the Precambrian to Lower Palaeozoic rocks of Northern Nigeria. A review In: C.A. Kogbe, (Editor), Geology of Nigeria. Elizabethan Publication Company.
[16] Grant, N. K. (1970). Geochronology of Precambrian Basement rocks from Ibadan, Southwestern Nigeria: Earth and Planetary Sciences letter. 10, 29-38.
[17] Egbuniwe, E.G. (1982). Geotectonic evolution of the Maru Belt, N.W. Nigeria. Unpubl. PhD thesis, Univ. Wales, Aberstwyth.
[18] Harker, A, The Natural History of Igneous Rocks. Methuen, London. (1909).
[19] Garrel, R.M., and Mackenzie, F.T. (1971): Evolution of Sedimentary Rocks. W.W Norton and Co. Int. New York, 394 p.
[20] Pearce M., Gorman, B.E., and Birkett, T.C. (1975): The Relationship between Major Element Chemistry and Tectonic Environment of Basic and Intermediate Volcanic Rocks. Earth and Planetary Science Letters.
[21] Dombrowski, A., Henjes-Kunst, F., Hohndorf, A., Kroener, A., Okrusch, M., and Richter, P. (1995): Orthogneisses in the Sperssart Crystalline Complex, north-west Bavaria: Silurian granitoid magmatism at an active continental margin. Geol. Rundsch. 84, 399-411.
[22] Leyleroup, A., Duppy, C., and Andriambolona, R. (1977): Chemical composition and consequence of the evolution of the French Massif Central Precambrian crust. Contrib. Mineral Petrol. Vol. 62: 283-300.
[23] Middleton, E.V. (1960): Chemical Composition of Sandstone. Bull. Geol. Soc. of America, 71, 1011-1026.
[24] Irvine, T.N., and Baragar, W.R.A. (1971): A guide to the chemical classifications of the common volcanic rocks. Canada Journal Earth Science. Vol. 8, pp. 523-548:https://doi.org/10.1139/e71-055.
[25] Rickwood, P.C. (1989): Boundary lines within petrologic diagrams which use oxides of major and minor elements. Lithos, 22:247-263.
[26] Condie, K. C. (1967). Geochemistry of early Precambrian graywackes from Wyoming. Geochimica et Cosmochimica Acta, 31(11), 2135-2149.
[27] Maniar, P.D. and Piccoli, P.M. (1989): Tectonic discrimination of granitoids. Geol. Soc. Amer. Bull. 101, 635-643.
Download all article in PDF
