Geophysical Interpretation of Possible Gold Mineralization Zones in Kyerano, South-Western Ghana Using Aeromagnetic and Radiometric Datasets

Abstract

Airborne magnetic and radiometric datasets are used to interpret the geology and geological structural patterns which serve as potential gold mineralization zones in the Kyerano area located at southwestern boundary of the prospective Sefwi Gold Belt and the Kumasi Basin in southwestern Ghana. The geophysical data processing approach adopted concentrated on mapping geological boundaries, geological structures and possible gold mineralization zones is link to hydrothermally altered zones. The application of the enhancement filtering algorithms such as the reduction to the pole and analytic signal to the magnetic data, as well as the ternary radiometric image aided in the mapping of the mafic metavolcanics, basin metasediments and the belt-type granitoid complexes. The first vertical derivative and tilt angle derivative filters helped to delineate fractures, folds, and the contact zones of the formations such as that of the metavolcanics-metasediments that host the main Bibiani Shear Zone. Lineament analysis of the structures using rose diagram, reveals two main tectonic episodes in the area. These are NE-SW and NNW-SSE trending regional structures which account for about 90% of the extracted structures and are associated with the D1 and D2 deformational episodes of the Birimian Formation respectively. These structures are major fracture systems and play a pivotal role in the localization of gold mineralization in the study area.

A review of the Birimian Supergroup- and Tarkwaian Group-hosted gold deposits of Ghana

“…Five lode gold case studies were presented, together with two on alluvial gold deposits. The interested reader will find Barning (1990) of use with regards to the conventional exploration techniques that are still important in modern exploration (Nude and Arhim, 2009;Arhim, 2013;Tisbaoh and Grant, 2009;Wemegah et al, 2015).…”

Interpretation of Geological Structures Hosting Potential Gold Deposits in the Konongo Gold Mine Using Airborne Magnetic, Electromagnetic and Radiometric Datasets

“…The "Galamsey" activity has led to the contamination of soils and river bodies in the area with traces of gold. Hence, the traditional method of exploring for gold through geochemical means becomes marred (Wemegah et al, 2015).…”

“…These are the main controlling features of the Birimian gold mineralization of Ghana. Various researchers have over the years adopted airborne geophysical methods namely magnetic, electromagnetic and radiometric methods in the delineation of potential mineralization zones (Morgan, 2012;Boadi, Wemegah, & Preko, 2013;Wemegah et al, 2015). The magnetic method uses the difference in units.…”

“…The magnetic method uses the difference in units. This has helped in the mapping of the geological and exploration for mineral deposits particularly in areas with limited outcrops (Jaques et al, 1997;Porwal, Carranza, & Hale, 2006;Allek & Hamoudi, 2008;Boadi, Wemegah, & Preko, 2013;Graham, Wemegah, & Preko, 2014;Wemegah et al, 2015;Rani et al, 2019). Boadi, Wemegah, & Preko (2013) interpreted airborne magnetic and radiometric data within the northeastern part of the Ashanti Greenstone Belt to delineate the geology and the associated structures in the area.…”

“…Generally, different geological environments including mineralized zones have different composition and distribution of these radioelements. This method, therefore, assists in locating mineral deposits using the differences in the composition of the three radioelements in association with the ore and the hosting rocks (Gunn & Dentith, 1997;Boadi, Wemegah, & Preko, 2013;Wemegah et al, 2015). It also determines near surface alteration which is associated with potassium enrichment or depletion in the hosting environment of the deposit (Morgan, 2012;Thomas et al, 2000).…”