Geological and structural interpretation of the Beposo area in the Ashanti region of Ghana, using aeromagnetic and radiometric data-sets

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April 2015
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Aeromagnetic and radiometric data-sets, acquired over the Beposo area in the Ashanti region of Ghana, were used to come out with an integrated geological and structural map, that will help in delineating possible gold mineralisation zones. Important new information on the extent of the lithology and structure which led to a more comprehensive understanding of areas of poor outcrop or under cover were obtained through the use of magnetic enhancement transforms such as analytical signal, first vertical derivative, horizontal derivative and tilt derivative on the magnetic dataset. The first vertical derivative and tilt derivative together with the horizontal derivative map helped in tracing out geological structures such as the Ashanti shear and faults which probably served as conduits for hydrothermal fluids and their resulting gold concentration. A rose diagram of the strike of geological structures in the area indicated that most of these structures are striking between 00 and 900 in the NE-SW direction and dipping to the NE. Granitoid intrusions which probably caused isoclinal folds in the Birimian were clearly defined by the aeromagnetic and radiometric data-sets. The radiometric dataset provided geochemical (K, eTh, eU) information that helped in interpreting surface lithology and possible hydrothermal alteration zones.
A thesis submitted to the Department of Physics, Kwame Nkrumah University of Science and Technology, in partial fulfilment of the requirements for the degree of Master of Philosophy(Geophysics) College of Science, 2015