Examination of the Pan-African Orogeny: Implications on the Architecture of Basement Rocks in Igarra, Southwestern Nigeria

Eseroghene Martin Udi; Okpeseyi Isaac Imasuen; Enivwenaye Oghenero Avwenagha; Ovie Odokuma-Alonge

Eseroghene Martin Udi Department of Geology, University of Benin, Benin-City, Nigeria
Okpeseyi Isaac Imasuen Department of Geology, University of Benin, Benin-City, Nigeria
Enivwenaye Oghenero Avwenagha Department of Earth Sciences, Arthur Jarvis University, Calabar, Nigeria
Ovie Odokuma-Alonge Department of Geology, University of Benin, Benin-City, Nigeria

Keywords: Pan-African Orogeny, Igarra, Fault zone, Breccia, Schist Belt, Evolution

Abstract

Investigation of basement rocks around Igarra, Southwestern Basement Complex of Nigeria was carried out to assess the impact of the Pan African Orogeny on the architecture and evolution of rocks in the study area. The area spans approximately 40km2 covering Igarra town and environs in Akoko-Edo Local Government Area of Edo State, Nigeria. The investigation includes systematic mapping and interpretations of structural elements in the rocks using standard geological techniques. The granites and metasediments were dissected by a network of quartzo-feldspathic dykes and veins of various dimensions. The Pan-African orogeny had been documented as the most pervasive of all the tectonic events that affected the Nigeria Basement rocks. Field mapping of the area revealed that the Pan-African granites are structurally controlled intrusions in the host metasedimentary rock sequence. The syn to late tectonic emplacements of the Pan-African granitoids during the neoproterozoic period (600 Ma ± 150 Ma) has affected the evolution of the rocks. The granite intruded the folded metasediments in N-S direction and their emplacements reactivated the E-W fault zone in the country rocks with injection of magmatic materials into dilation zones in the metasediments and fault breccias within Igarra and environ.

References

Ajibade, A.C., Woakes, M., Rahaman, M.A., 1989. Proterozoic Crustal Development in The Pan African Regime of Nigeria. In: Kogbe, C. A. (Editor) Geology of Nigeria. Rock View, Jos, 57-69.

Akintola, O.F., Adekeye, J.I.D., 2008. Mineralization Controls and Petrogenesis of the Rare Metal Pegmatites of Nasarawa Area, Central Nigeria. Earth Sciences Research Journal 12 (1), 44-61.

Annor, A.E., Freeth, S.J., 1985. Thermotectonic evolution of the Basement Complex around Okene, Nigeria, with special reference to deformation mechanism. Precambrian Research 28, 269-281.

Annor, A.E., Olasehinde, P.I., Pal, P.C., 1990. Basement fracture patterns in the control of water channels – An example from Central Nigeria. Journal Mining and Geology, 26 (1), 5-12.

Danbatta, U.A., 2010. On the Evolution of the Kazaure Schist Belt of NW Nigeria: A Re-Interpretation. Global Journal of Geological Sciences 8 (2) 207-216.

Jones, H.A., Hockey, R.D., 1964. The geology of part of South-Western, Nigeria. In: Rahaman, M. O., 1988. Recent Advances in the study of the Basement Complex of Nigeria. In: Oluyide, P. O., Mbonu, W. C., Ogezi, A. E., Egbuniwe, I. G., Ajibade, A. C. and Umeji, A. C., (Eds). Precambrian Geology of Nigeria, Geological Survey of Nigeria Publication, Kaduna, 11-41.

MacDonald, A.M., Cobbing, J., Davies J., 2005. Developing groundwater for rural water supply in Nigeria. British Geological Survey Commissioned Report CR/05/219N.

Obiadi, I.I., Obiadi, C.M., Ajaegwu, N.E., Anakwuba, E.K., Onuigbo, E.N., Maduewesi, V., Chinenye, O., Ezim, O.E., 2015. Structural evidence for Pan-African event in The South West basement block of Nigeria: The Igarra Example. Journal of Basic and Applied Research International 3 (2), 66-74.

Oden, M.I., Udinmwen, E., 2014. Fracture characterization, mineral vein evolution and the tectonic pattern of Igarra syn- tectonic granite, Southwestern Nigeria. British Journal of Applied Science and Technology 4 (17), 2417-2429.

Odeyemi, I.B., 1976. Preliminary report in the relationships of the Basement complex rocks around Igarra, Mid-west. In: Geology of Nigeria, Kogbe, C. A. (Editor). Elizabethan Publishers, Lagos 59-63.

Odeyemi, I.B., 1988. Lithostratigraphic and Structural Relationships of the Upper Precambrian Metasediments in Igarra area, Western Nigeria. In: Oluyide, P.O., Mbonu, W.C., Ogezi, A.E., Egbuniwe, I.G., Ajibade, A.C., Umeji, A. C., (Eds), Precambrian Geology of Nigeria. A Publication of Geological Survey of Nigeria, Kaduna, 111-125.

Ogbe, O.B., Olobaniyi, S.B., Ejeh, O.I., Omo-Irabor, O.O., Osokpor, J., Ocheli, A., Overare, B., 2018. Petrological and Structural Investigation of rocks around Igarra, Southwestern Nigeria. Ife Journal of Science 20 (3), 663-677. https://dx.doi.org/10.4314/ijs.v20i3.19.

Ogunyele, A.C., Obaje, S.O., Akingboye, A.S., 2018. Lithostructural Relationships and Petrogenetic Affinities of the Basement Complex Rocks around Okpella, Southwestern Nigeria. Earth Sciences Malaysia 2 (1), 29-36.

Oluyide, P.O., 1998. Structural Trends in the Nigerian Basement Complex. In: Oluyide, P.O., Mbonu, W. C., Ogezi, A. E., Egbuniwe, I. G., Ajibade, A. C., and Umeji, A. C. (Eds). Precambrian Geology of Nigeria. Geological Survey of Nigeria Publication, Kaduna, 93-98.

Oyawoye, M.O., 1972. The basement complex of Nigeria. In: Dessauvagie, T. F. and Whiteman, A. J. (eds). African Geology. Ibadan, Geology Department, University of Ibadan, 42-98.

Rahaman, M.O., 1988. Recent Advances in the study of the Basement Complex of Nigeria. In: Oluyide, P. O., Mbonu, W. C., Ogezi, A. E., Egbuniwe, I. G., Ajibade, A. C. and Umeji, A. C., (eds). Precambrian Geology of Nigeria, Geological Survey of Nigeria Publication, Kaduna, 11-41.

Turner, D.C., 1983. Upper Proterozoic Schist Belts in the Nigerian Sector of the Pan-African Province of West-Africa. In: Kogbe, C. A. (Editor) Geology of Nigeria, Rock View, Jos. 93-109.

Udinmwen, E., Oden, M.I., Ayuba, R., Asinya E.A., 2016. Structural Control on Mineral Vein Geometry in the Igarra Schist Belt, Southwestern Nigeria. Journal of Earth and Atmospheric Sciences (1), 10-21.

Woakes, M., Rahaman, M.A., Ajibade, A.C., 1987. Some Metallogenetic features of the Nigerian Basement. Journal. of African. Earth Sciences 6, 164-655.

Woodcock, N.H., Mort, K., 2008. Classification of Fault Breccias and related fault rocks. Geological Magazine 145 (3), 435-440.