Magnetic mineral exploration using ground magnetic survey data of Tajimi Area, Lokoja

Abstract

Ground magnetic survey is an essential geophysical method employed in locating subsurface magnetic materials for possible exploration. In geophysics, the  anomalous magnetization might be associated with local mineralization that is potentially of commercial interest. Hence a ground magnetic survey was carried out at a site in Tajimi area of Lokoja, Kogi State, Nigeria. The study is aimed at locating the position of iron deposited minerals within the study area. The study area lies within Latitude 800292ˈN to 800625ˈN and Longitude 605833ˈE to 606167ˈE in the basement complex of Southern Nigeria. A total of fifteen magnetic transverse lines were established in an E-W direction in the study area covering 140m by 75m. Data were taken and recorded using Proton Precession magnetometer; the data were presented in magnetic profiles, 2D contour map and 3D surface map which aided the qualitatively interpretation. The study area was characterized by  completely varying magnetic anomaly amplitudes across the field. The field data were quantitatively interpreted and the results gave values for the total component  measurements of the ground magnetic anomaly that varied between a minimum  negative peak value of about -23428.7nT and a maximum positive peak value of  about 5840.9nT. The residual anomalies obtained were plotted against distance  using Microsoft Excel and Analytic signal method was used to estimates the depth to the magnetic source body. The estimated depths of the magnetic source  body/rocks from the Earth surface fall in the interval of 1.28m to 13.57m, which  indicates the magnetic source body suspected to be magnetic mineral, are near surface features. Hence a careful analysis of the magnetic anomaly maps can give vital information about the magnetic distribution and mineral potential of the study
area at Tajimi.