Structurally Controlled Prospectivity Map of the Sefwi Volcanic Orogenic Belt of Ghana

Fareed Majeed, Isaac Dadzie, Gordon Foli, Kwaku Tekyi Kyeremeh


In this study, datasets obtained from ground magnetic and electrical geophysical surveys were integrated with existing solid geology, structural lineaments to map out structures in the Sefwi Belt of Southern Ghana. The prospecting and exploration stages of mining involve long periods of investment with a high risk of failure. In view of that, prospecting for gold needs to be optimised and that requires choosing the right techniques that will enhance the success of the exploration projects. It is for this reason that this paper exploits the integration of geological, geophysical (magnetic and electrical) and structural dataset to produce a prospective map of the study area. Elrec Iris 10 channel Induced receiver and Geometrics 859 magnetometer were used for Induced Polarisation (IP) and Resistivity and Magnetic data acquisition respectively. The magnetic data obtained were corrected and enhanced using Reduced to pole (RTP), 1 vertical derivative and analytical signal filters. The outcome of the electrical resistivity and IP inversions indicated that depths ranging from 50 to 200 m suggest conductive and chargeable bodies. The low-resistivity zones coincided with sheared and altered acidic meta-sediments. The geophysical signatures obtained from the enhanced magnetic data and the electrical data showed that the study area is structurally complex with a few of the structures corresponding to D1 deformation and most structures corresponding to D2 deformation. The study resulted in better illuminating geological structures and lithological boundaries, and thus has demonstrated the worth of geophysical data as an enhancement tool in mapping possible geological structures that host hydrothermal gold mineralisation within the Sefwi volcanic orogenic gold belt of Ghana. Seven diamond drill holes were intuitively planned to test the hypothesised model and determine the depth of the resistive-chargeable anomalous units as well as litho-structural boundaries.


Volcanoclastic, Birimian, Metavolcanic, Auriferous, Pole-dipole, Reduce-to-pole

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