Investigation of the subsurface features of the basement complex of northern Nigeria using 3D seismic reflection data

Abstract

3D seismic reflection survey was recently carried out within the Zaria area of the basement complex of northern Nigeria, in order to investigate the complexity of the subsurface features within the basement. The geology of the survey area was characterized by gneisses and low grade meta-sedimentary rocks that form the country rock into which the granitic batholith intruded. Measurements along individual 2D seismic profile lines spaced at 4 m interval, with an offset of 10 m each, and geophone spacing of 1 m along each line were carried out. From the result of the 3D seismic reflection survey, the contact between the overburden and the weathered basement was delineate, so also the topography of the fresh basement and the suspected sill within the subsurface. The 2D surfaces were combined to give a 3D picture of the subsurface within the survey area. The resulting 3D wire-frame representation showed that the topography of the basement rock, within the subsurface, changed over a very short distance. The result also showed that an attempt to predict the nature of the subsurface based on the outcrops within the vicinity without a detailed high resolution seismic survey could be very misleading.

Keyword: 3D seismic reflection, basement complex, geology, meta-sedimentary rocks, Nigeria

International Journal of Natural and Applied Sciences, 5(4): 379-384, 2009