EVALUATION OF DEPTH TO BASEMENT, HEAT FLOW, AND LEAD-ZINC MINERALIZATION FROM ANALYSIS OF AEROMAGNETIC DATA IN SOME PARTS OF SOUTHERN BENUE TROUGH

Abstract

The techniques of aeromagnetic data analysis were employed to elucidate depth to magnetic basement sources, lead-zinc (pb-zn) mineralisation and heat flow in parts of Southern Benue Trough. The study area covers an area extent of about 18,150 sq. Km, latitude 05 0 30’N - 06 0 30’N and longitude 007 0 30’E - 009 0 00’E. The digital aeromagnetic data consisting of Total Magnetic Intensity with geospatial attributes covering six (6) sheets 302 (Nkalagu), 303 (Abakaliki), 304 (Dangha), 313 (Afikpo), 314 (Ugep) and 315 (Ikom) were used in this study. Several magnetic digital filtering methods such as reduce to pole, low/high pass, etc were applied on the data before analysis for lineaments, mineralisation, and depth to magnetic sources. Zones of broad magnetic anomalies were found in the north eastern and south eastern part of the study area like Otam-Izekwe, Enyigba, Uburu, Abakaliki, Ndieze Izzi, Isiagu, Obubra, Oturekpe, Mkpani, Idomi, Enona, Ugep, etc. Depth estimates to the magnetic basement sources from spectral analysis range from 0.65km to 1.155 km, while depth estimate from source parameter imaging (SPI) stretches from 0.679km to 7.723km. The north western part of the study area is the deepest. Pb-zn mineralization within the study area is found to be structurally controlled trending in NE-SW and NW – SE directions. The heat flow values range from 0.65 – 1.95Wm -2 , pb-zn mineralization is within 0.9 – 1.4Wm -2 and Curie point depth range from 0.75km to 2.1km. Keywords: Depth to basement, Heat flow, Lead-Zinc, Mineralization, Aeromagnetic data DOI: 10.7176/JEES/13-2-06 Publication date: March 31 st 2023