keywords: Aeromagnetic, imaging, modeling, potent, residual, Nsukka, Udi
Aeromagnetic data analysis and interpretation of Udi sheet and that of Nsukka sheet in Enugu State, Anambra Basin was carried out. The data which were obtained by Nigeria Geological Survey Agency (NGSA) were interpreted qualitatively and quantitatively.Source Parameter Imaging and Forward and Inverse Modeling methods were employed to interpret the data quantitatively to obtain the intrusive bodies and their respective depth to basement. The depths to the magnetic bodies’ estimated using Source Parameter Imaging (SPI) method after some data processing like first order derivative ranges from 0.4723 km – 6.0518 km, In the forward and inverse modeling techniques seven profiles were taken on the residual map and were modeled, thus revealing some special features of the study area. These results show six intrusive bodies: pyrryhotite, ironstone, sandstone in some parts of Nsukka area and granite, gabbro or basalt, sandstone and olivine in some parts of Udi area with their respective depths and susceptibilities. The depths of the minerals obtained ranges from 0.835 km to 5.321 km.
Adetona AA & Abu M 2013. Investigating the structures within the Lower Benue and upper Anambra Basins, Nigeria, using first vertical derivative, analytical signal and (CET) Center for Exploration Targeting Plug in Earth Sci., 2(5): 104-112. Ajayi C.O & Ajakaiye DE 1981. The origin and peculiarities of the Nigeria Benue Trough: Another look from recent gravity data obtained from the Middle Benue Tectonophysics, 80: 285. Bahattacharrya BK 1966. Continuous spectrum of the total magnetic field anomaly due to rectangular prismatic body. Geophysics, 31: 97 – 121. Eze ID 2011. Forward and Inverse Modeling of aeromagnetic data for minerals and intrusive in Abakiliki area, Ebonyi State. Unpublished M.Sc. Thesis, University of Nigeria Nsukka. Ezema PO, Eze ID, Ugwu GZ & Abudullahi UA 2014. Hydrocarbon and mineral exploration in Abakiliki, Southeastern Nigeria. Int. J. Eng. Sci., 3(1): 24 - 30. Federal Republic of Nigeria Official Gazette 2007. Legal notice on Publication of the details of the breakdown of National and State provisional totals 2006 census No. 24 vol. 94. Geophysical Software Solutions 2010 Potent version 4, G.S.S., Australia, www.geoss.com.au, (Retrieved on 20th June 2015). Obi DA, Okereke CS, Obei BC & George AM 2010. Aeromagnetic modelling of subsurface intrusive and its implications on hydrocarbon evaluation of the Lower Benue Trough, Nigeria. European J. Sci. Res., 47(3): 347 – 361. Obiora DN, Mirianrita NO & Emmanuel O 2015. A case study of aeromagnetic data interpretation of Nsukka area, Enugu State, Nigeria for hydrocarbon exploration. Int. J. Physical Sci., 10(7): 503 – 519. Ofoegbu CO 1984. Interpretation of aeromagnetic anomalies over the lower and middle Benue Trough of Nigeria. Geophys. J.R. Astro. Soc., 79: 813-823. Ofoegbu CO 1985. A review of Geophysical Investigations in the Benue Trough, Nigeria. J. Afr. Earth Sci., 3: 283. Petters SW 1978. Stratigraphic evolution of Benue Trough and its implications for the Upper Cretaceous Paleogeography of West Africa. J. Min. Geol., 13(2): 20 – 27. Revees C 2005. Aeromagnetic Surveys: Principles, Practice and Interpretation, GEOSOFT, Netherlands. Richard SS, Jeffrey BT, Ting FD & Lan NM 1998. The improved source parameter imaging method. Geophysical Prospecting, 46: 141 – 151. Robinson ES & Coruh C 1998. Basic Exploration Geophysics, 1st Edition. John Wiley and Sons New York, p. 120. Salako KA 2014. Depth to basement detrmination using source parameter imaging (SPI) of aeromagnetic data: An application to upper Benue Trough Borno Basin, Northeast, Nigeria. Int. Res. J., 5(3): 74 – 86. Samuel OA, Olusola JO & Olabisi AA 2011. Stratigraphic evolution and petroleum potential of middle cretaceous sediments in the lower and middle Benue Trough, Nigeria: Insight from New Source Rock Facies Evaluation. Petroleum Techn. Devt. J., 1: 34 – 47. Telford WM, Geldart LP & Sheriff RE 1990. Applied Geophysics, second edition. Cambridge University Press, Cambridge. Thurston JB & Smith RS 1997. Authomatic conversion of magnetic data to depth, dip, and susceptibility contrast using 〖SPI〗^TM method. Geophysics, 59: 546 – 813. Ugwu GZ & Ezema PO 2012. Forward and inverse modeling of aeromagnetic anomalies over Abakaliki and Nkalagu areas of the Lower Benue Trough, Nigeria. Int. Res. J. Geol. Mining, 2(8): 222-229. Ugwu GZ, Ezema PO & Ezeh CC 2013. Interpretation of aeromagnetic data over Okigwe and Afikpo areas of lower Benue trough, Nigeria. Int. Res. J. Geol. Mining, 3(1): 1–8. Wright JB 1976, Origins of the Benue Trough – A Critical Review. In: Geology of Nigeria, Kogbe, CA (ed). Elizabethan Publ. Co. Lagos, pp. 309 – 318. Wright JB, Hastings D, Jones WB & Williams HR 1985. Geology and Mineral Resources of West Africa. George Allen and Urwin, London, pp. 90 – 120.