MAGNETIC RESPONSE ANALYSES IN PARTS OF SOUTHERN BENUE TROUGH: IMPLICATIONS FOR MINERAL PROSPECTING

Abstract

This study presents an analysis of high-resolution aeromagnetic data from parts of the Lower Benue Trough, specifically covering regions in Abia, Imo, Enugu, Anambra, Ebonyi, Cross River, and Benue States, situated between latitudes 05° 00ʹ N and 07° 00ʹ N and longitudes 07° 30ʹ E and 09° 00ʹ E. The data was obtained from nine aeromagnetic sheets (numbers 287, 288, 289, 301, 302, 303, 312, 313, and 314), which cover Nsukka, Igunmale, Ejekwe, Udi, Nkalagu, Abakaliki, Okigwe, Afikpo, and Ugep. The Total Magnetic Intensity (TMI) map of the study area revealed magnetic intensity values ranging from -47.3 nT to 151 nT, with the highest intensity observed in the northern part of the study area near Bende, where a prominent NE-SW trend was noted. The reduction to equator (RTE) showed a range of -34.84 nT to 135.26 nT, with significantly high-intensity anomalies observed around Okigwe, Isiukwuato, and Afikpo. The regional anomaly map revealed deeply seated rocks around Isuikwuato and Okigwe, marked by a prominent NE trend. Upward continuation of the data at heights of 50 m, 500 m, 5 km, and 10 km demonstrated a decrease in near-surface magnetic responses, confirming that as the upward continuation height increased, the regional magnetic anomaly became more pronounced. These findings indicate the presence of magnetic intrusions in the North-Eastern and South-Western parts of the study area, making it a viable region for mineral exploration. The results are consistent with previous studies in the region, further supporting the potential for mineral prospecting.