Geochemistry of the Precambrian Basement of the Bamenda massif of southeastern Nigeria: petrogenesis and tectonic setting

Authors

DOI:

https://doi.org/10.1344/GeologicaActa2020.18.19

Keywords:

crustal anatexis, Petrogenesis, Fractionation, Tectonism, LREE enrichment.

Abstract

Trace and Rare-Earth element geochemical study of twenty samples of migmatitic banded gneisses, garnet biotite schists, dolerites, granites and rhyolites was carried out in a bid to determine their petrogenetic and tectonic significance in the evolution of the southeastern Basement complex of Nigeria. The data shows that partial melting (crustal anatexis) of migmatitic gneisses and schists played a significant role in the evolution of the granitic intrusions. This is supported by the high incompatible (Rb/Sr = 0.16 to 1.31 and Ba/Sr = 0.75 to 6.21) elements ratio in the granitic intrusions than that of the migmatitic gneisses and schists (Rb/Sr, 0.051 to 0.824; Ba/Sr, 0.7 to 5). High ratios of Ba/Sr and Rb/Sr and lesser values of Ba/Rb ratios in some granitic intrusions than in others suggests increasing fractionation during the anatexis. The role of partial melting is also evident in the smooth REE patterns shown by most of these rocks and the negative Eu anomaly as indicated by the values of Eu/Eu* (0.097 to 0.7). LREE enrichment is evident in the high values of Ce/YbN (12.08-174.5), La/YbN (15.2-228.4) and La/SmN (2.6-7.2) in the granitic intrusions. Tectonic discrimination diagrams of the rocks indicate that the basement rocks were most probably formed in a post-collision orogenic setting while the dolerite and the rhyolite were formed in within-plate anorogenic setting.

Author Biography

C.U. Ibe, University of Nigeria, 410001 Nsukka.

Lecturer II Department of Geology University of Nigeria, Nsukka. Orcid: 0000-0002-6708-3520

References

Anike, O.L., Umeji, A.C., Orajaka, I.P., 1993. Geology of Precambrian Banded Iron formation from Muro Hill, Nigeria. Economic Geology, 88, 1237-124.

Brown, M., 1994. The generation, segregation, ascent and emplacement of granite magma: the Migmatite-to-crustallyderived granite connection in thickened orogens. Earth Science Reviews, 36, 83-130.

Castro, A., Moreno-Ventas, I., De la Rosa, J.D., 1991. H-type (hybrid) granitoids: a proposed revisión of the granite type classification and nomenclature. Earth-science reviews, 31(3-4), 237-253.

Chappell, B.W., 1996. Magma mixing and the production of compositional variation within granite suites: evidence from the granites of southeastern Austrailia. Journal of Petrology, 37(3), 449-470.

Clemens, J.D., 1990. The granulite-granite connection. In: Vielzeuf, D., Vidal, Ph. (eds.). Granulites and crustal evolution. Dordrecht, Kluwer, 25-36.

Cordani, U.G., Pimentel, M.M., Ganade de Araújo, C.E., Basei, M.A.S., Fuck, R.A., Girardi, V.A.V., 2013. Was there an Ediacaran Clymene ocean in central South America? American Journal of Science, 313, 517-539.

Emmermann, R., Daieva, L., Schneider, J., 1975. Petrologic significance of rare earths distribution in granites. Contributions to Mineralogy and Petrology, 52, 267-283.

Floyd, P.A., Winchester, J.A., 1975. Magma type and tectonic setting discrimination using immobile elements. Earth and planetary science letters, 27, 211-218.

Fourcade, S., Allergre, C.J., 1981. Trace elements behaviour in granite genesis: a case study. The calc-alkaline plutonic association from the Quergut Complex (Pyrénées, France). Contributions to Mineralogy and Petrology, 76, 177-195.

Frost, T., Mahood, G.A., 1987. Field, chemical and physical constraints on mafic-felsic magma interaction in the Lamarck

Granodiorite, Sierra Nevada, California. Geological Society of America Bulletin, 99(2), 272-291

Harris, N.B.W, Pearce, J.A., Tindle, A.G., 1986. Geochemical characteristics of collision-zone magmatism. Geological Society, London, 19 (1, special publications), 67-81.

Haskin, L.A., Haskin, M.A., Frey, F.A., Wildman, T.R., 1968. Relative and absolute terrestrial abundances of the rare-earths. In: Ahrens, L.A. (ed.). Origin and distribution of elements. Oxford, Pergamon, 1, 889-911.

Hers, N., Dutra, C.V., 1960. Minor element abundance in a part of the Brazillian Shield. Geochimica et Cosmochimica Acta, 21, 81-98.

Ibe, C.U., Obiora, S.C., 2019. Geochemical characterization of Granitoids in Katchuan Irruan area: further evidence for peraluminous and shoshonitic compositions and postcollisional setting of granitic rocks in the Precambrian Basement Complex of Nigeria. Acta Geochimica, 38(5), 734-752.

Ibe, C.U., 2020. Geochemical characterization of the gneisses and schists in Ekumtak area: further evidence for a metasedimentary protolith and moderate weathering intensity for the Precambrian Basement complex of Nigeria. Serie

Correlación Geológica, 35(2), 17-36.

Lambert, I.B., Heier, K.S., 1968. Geochemical investigations of deep-seated rocks in the Austrailian shield. Lithos, 1, 30-53.

Malomo, S., 2004. Geological Map of Nigeria, 1:2,000,000. Published by the Nigeria Geological Survey Agency.

Neves, S.P., Vauchez, A., 1995. Successive mixing and mingling of magmas in a plutonic complex of Northeast Brazil. Lithos,

, 275-299.

Nockolds, S.R., Allen, R., 1953. The geochemistry of some igneous rock series. Geochimica et Cosmochimica Acta, 4, 105-142.

Obiora, S.C., Umeji, A.C., 1997. An appraisal of the use of discrimination diagrams in the tectonomagmatic classification of Igneous Rocks in Nigeria. Jos 1997, Annual International Conference of the Nigeria Mining and Geoscience Society, 33 (abstracts), 47.

Obiora, S.C., 2005. Field Description of Hard Rocks, with examples from the Nigeria Basement Complex. Enugu (Nigeria), SNAAP Press Ltd., 44pp.

Obiora, S.C., 2006. Petrology and geotectonic setting of Basement Complex rocks around Ogoja, southeastern Nigeria. Ghana Journal of Science, 46, 13-25.

Obiora, S.C., Ukaegbu, V.U., 2009. Petrology and Geochemistry Characteristics of Precambrian granite Basement Complex rocks in the southernmost part of North Central Nigeria. Chinese Journal of Geochemistry, 28(4), 377-385.

Obiora, S.C., 2012. Chemical characterization and tectonic evolution of Hornblende-Biotite granitoids from the Precambrian basement complex around Ityowanye and Katsina-Ala, Southeastern Nigeria. Journal of mining and Geology, 48, 13-29.

Olarewaju, V.O., 1987. Charnockite – granite association in SW, Nigeria: Rapakivi granite type and charnockitic plutonism in

Nigeria? Journal of African Earth Sciences, 6(1), 67-77.

Onyeagocha, A.C., 1986. Geochemistry of basement granitic rock from northcentral Nigeria. Journal of African Earth Sciences, 5(6), 651-657.

Oyawoye, M.O., 1964. The geology of the Nigerian Basement Complex- A survey of our present knowledge of them. Nigerian Mining, Geological and Metallurgical Society, 1, 87-102.

Oyawoye, M.O., 1972. The Basement Complex of Nigeria. In: Dessauvagie, T.F.J., Whiteman, A.J. (eds.). Ibadan, African Geology. Ibadan University Press, 67-99.

Pearce, J., Cann, J.R., 1973. Tectonic setting of basic volcanic rocks determined using trace element analysis. Earth and Planetary Science Letters, 19, 290-300.

Pearce, J.A., Norry, M.J, 1979. Petrogenetic implications of Ti, Zr, Y and Nb variations in volcanic rocks. Contributions to Mineralogy and Petrology, 69, 33-47.

Pearce, J.A., Harris, N.B.W., Tindle, A.G., 1984. Trace element discrimination diagram for the tectonic interpretation of granitic rocks. Journal of Petrology, 25(4), 956-983.

Pearce, J., 1996. Sources and settings of granitic rocks. Episodes, 19(4), 120-125.

Price, C., Mueke, G.K., 1980. Rare-earth geochemistry of the Scourian complex N.W Scotland–Evidence for the granitegranulite link. Contributions to Mineralogy and Petrology, 73, 403-412.

Rahman, A.M.S., Ekwere, S.J., Azmatullah, M., Ukpong, E.E., 1988. Petrology and geochemistry of granitic intrusive rocks from the western part of Oban Massif, Southeastern Nigeria. Journal of African Earth Sciences, 7, 149-157.

Rajesh, H.M., 2007. The petrogenetic characterization of intermediate and silicic charnockites in high-grade terrains: A case study from southern India. Contributions to Mineralogy and Petrology, 154, 591-606.

Rollinson, H.R., 1993. Using geochemical data: Evaluation, Presentation and Interpretation. United Kingdom (UK), Longman, 352pp.

Sawyer, E.W., 1996. Melt segregation and magma flow in migmatites: implications for the generation of granite magmas. Transactions of the Royal Society of Edinburgh: Earth Sciences, 87, 85-94.

Sawyer, E.W., 1998. Formation and evolution of granite magmas during crustal reworking: the significance of diatexites. Journal of Petrology, 39, 1147-1167.

Singh, A.K., Singh, R.K.B, Vallinayagam, G., 2006. Anorogenic acid volcanic rocks in the Kundal area of the Malani Igneous

suite, Northwestern India: Geochemical and Petrogenetic studies. Journal of Asian Earth Sciences, 27(4), 544-557.

Sun, S.S., McDonough, W.F., 1991. Chemical and isotopic systematic of oceanic basalts: implication for mantle composition and processes. In: Sunders, A.D., Norry, M.J. (eds.). Magmatic in Oceanic Basins. Geology Society of London, 42 (Special Publications), 313-345.

Taylor, S.R., 1965. The application of trace element data to problems in petrology. Physics and Chemistry of the Earth, 6, 133-213.

Thompson, R.N., 1982. British Tertiary volcanic province. Scottish Journal of Geology, 18, 49-67.

Ugwuonah, E.N., Tsunogae, T., Obiora, S.C., 2017. Metamorphic P-T evolution of garnet staurolite-biotite pelitic schist and amphibolites from Keffi, north central Nigeria: Geothermobarometry, mineral equilibrium modeling and P-T path. Journal of African Earth Sciences, 129, 1-16.

Ukaegbu, V.U., Ekwueme, B.N, 2006. Petrogenesis and geotectonic setting of the Pan African basement rocks in Bamenda massif, Obudu, southeastern Nigeria: Evidence from trace element geochemistry. Chinese Journal of Geochemistry, 25(2), 122-135.

Vielzeuf, D., Clemens, J.D., Pin, C., Moinet, E., 1990. Granites, Granulites and crustal differentiation. In: Vielzeuf, D., Vidal, Ph. (eds.). Granulites and crustal evolution. Dordrecht, Kluwer, 59-85.

Wang, X., Zhou, J., Qui, J and Gao, J. 2004. Geochemistry of Meso-to Neoproterozoic basic to acid rocks from Hunan Province, South China: implications for the evolution of the western Jiangnan orogeny. Precambrian Research. 135. 79-103

Winchester, J.A., Floyd P.A., Chocyk, M., Horbowy, K., Kozdroj, W. 1995. Geochemistry and tectonic environment of Ordovician meta-Igneous rocks in the Rudawy Janowickie Complex, SW Poland. Journal of the Geological Society of London. 152, 105-115.

Wood, D.A., 1980. The application of a Th-Hf-Ta diagram to problems of tectonomagmatic classification and to establishing the nature of crustal contamination of basaltic lavas of the British Tertiary Volcanic Province. Earth and Planetary Science Letters, 50, 11-30.

Wright, J.B., 1985. Geology and Mineral Resources of West Africa. London, George Allen and Unwin, 87pp.

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2020-12-07

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