2 nd African Geosciences Student Conference, 20 – 24 May 2014, Kumasi Application of Magnetic Method and Electrical Resistivity Tomography for Imaging Archaeological Structures at Iyekere, Ile-Ife Southwestern Nigeria K. D. Oyeyemi 1 , M.A Oladunjoye 2 , A.I Olayinka 2 and A.P. Aizebeokhai 1 email: kdoyeyemi@yahoo.com 1 Department of Physics, College of Science and Tech., Covenant University, Nigeria 2 Department of Geology, University of Ibadan, Nigeria Summary Magnetic and electrical resistivity tomography geophysical techniques were integrated to locate subsurface archaeological materials. The magnetic survey comprises seven profiles in N-S and E-W direction with station interval of 0.5 m. [Orthogonal set of] 2D electrical resistivity tomography data consisting of four parallel and three perpendicular profiles were collected using Wenner array with electrode spacing ranging from 0.5 – 3.0 m. Trial pits carried out at regions of high total magnetic intensity and model resistivity yield burnt pipes “TUYERE”, iron slag, iron smelting, and pottery fragments. Introduction Archaeological and environmental impact assessments as part of planning applications often require geophysical surveys. The geophysical surveys are designed to detect and define archaeological structures and features that may be hidden beneath the soil. Assessments normally take place in advance of projects such as road or pipe corridors, the building of single houses or estates and the development of industrial zones or mineral extraction sites. In the case of research projects and monument delimiting surveys, where there are known or visible archaeological monuments, geophysical surveys can be used to assess their possible hidden sub-surface extension and preservation, preservation potential or to prospect for undiscovered monuments in the locality. Geophysical methods provide fast, efficient and non-destructive reconnaissance techniques often required by archeologists. Also, geophysical techniques offer rapid, uniform, reconnaissance of an entire site together with a synoptic view of the interrelationships within the site (Weymouth and Huggings, 1985). Geophysical methods has been used to map healths, klins, buried bricks, building foundations, middens (trash heaps), burial tombs, ditches and soils compacted or excavated by previous human activities (Weymouth, 1986; Loperte et al 2011). In this study, high resolution geophysical methods involving magnetic method and electrical resistivity tomography (ERT) imaging have been used in the search for archaeological materials (iron slag pottery materials, burnt pipes or tuyere). The locations and approximate depths of these archaeological materials were obtained from the resulting geophysical images; pitting were carried out at these locations to verify the accuracy of the geophysical results. The study area, Iyekere, is within the ancient city of Ile-Ife in southwestern Nigeria. It is boarded by latitudes 4 0 30ꞌ N and 4 0 33ꞌ N and longitudes 7 0 22ꞌ E and 7 0 25ꞌ E (Fig. 1.1). Other settlements around the study area include Isoya, Alapata and Toro among others (Fig.1a). The rock types are predominantly granite-gneiss and pegmatite of the Older-granite complex. Schist and epidiorite complex belonging to gneiss-schist complex of the basement complex are the dominant rock type in north-eastern part of the area (Oyawoye, 1972) (Fig. 1b).