Interpretation of ground-based magnetic and gravity data for the delineation of potential gold mineralization zones in Subenso, Ghana

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October 27, 2015
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Data from integrated ground gravity and magnetic surveys were used to interpret the geology by delineating lithological units, geological structures as well as the delineation of potential gold mineralization zones within the Subenso South concession of Newmont Ghana Gold Limited. The two datasets were acquired along 3.6 km by 2.1 km block with 100 m profile line spacing and data was collected at 100 m station along the profile lines using L&R Gravimeter and Topcon DGPS for the ground gravity survey. Geometrics G856 and G858 were used in a continuous mode for the ground magnetic survey. Geosoft Oasis Montaj version 7.1 was used to process the data. Image enhancement techniques such as reduction to the pole and first vertical derivative aided in the delineation of geological structures like faults which are potential gold mineralization zones. A residual gravity map was produced from the gravity data which helped in enhancing the lithological contacts. The area is made up of predominantly metasedimentary units, mafic volcanic units and volcaniclastic units. The metasediments showed generally low magnetic and gravity responses. The mafic volcanic units showed high gravity and magnetic responses. Relatively intermediate gravity and magnetic responses were mapped as the volcaniclastic units. The superimposition of the Subenso South gold deposit on the gravity and magnetic results helped to establish a relationship between the mineralization zones in the area. The Subenso gold deposit was located on and along the contacts of the high gravity and magnetic anomalies. This relationship led to the delineation of unexplored potential gold mineralization zones in the study area.
A Thesis Submitted to the Department of Physics, Kwame Nkrumah University of Science and Technology in partial fulfillment of the requirements for the degree of Master of Philosophy,