Geophysical Imaging of Archaeological Materials at Iyekere, Ile-Ife Southwestern Nigeria

Abstract

Non-invasive geophysical methods are increasingly being used in archaeological studies. In this study, magnetic and electrical resistivity tomography geophysical techniques were integrated to locate subsurface archaeological materials. The survey consists of four parallel and three perpendicular profiles with station interval of 0.5 m for both magnetic and electrical resistivity tomography. Wenner array with electrode spacing ranging from 0.5 – 3.0 m was used to collect the electrical resistivity data. The results show that high total magnetic intensity anomalies correspond to high inverse model resistivities. The regions with high magnetic and resistivity anomalies were thought to be locations of archaeological materials; the corresponding depths to these materials were inferred from the resulting geophysical images. Test units conducted at the regions of high total magnetic intensity and inverse model resistivity yield archaeological materials including burnt pipes (Tuyere), iron slag, iron smelting, and pottery fragments at approximate depths inferred from the geophysical images.

Keywords: Archaeogeophysics, Artefacts, ERT, Magnetic methods, 2D imaging