Geophysical Contributions to Gold Exploration in Western Mali According to Airborne Electromagnetic Data Interpretations

Abstract

The Birimian of West African Craton (WAC) is known for its gold potential. Among Birimian structures, N-S and NE-SW trends have been defined as controlling gold mineralizations in Kedougou-Kenieba Inlier (KKI), whereas some of these structures are not gold-bearing. To determine structures related to gold mineralization, airborne electromagnetic data collected during the “Système Minier” of Mali have been processed and interpreted. Identified lineaments have been followed in the ground to establish their link with gold showings in the Kenieba area. Geophysical interpretations show trends similarity for different orders of conductivity. They allowed for characterizing resistance and conductive structures with prevalent N-S and NE-SW directionalities. Conductive structures are qualified as good conductors and are strongly related to known Artisanal Mining Sites (AMS). They coincide with tourmaline sandstones and quartz-albite veins, which are both often artisanally recognized as indicators of gold mineralization in Western Mali. Field observations show that resistance structures correspond to felsic rocks. These structures can bear gold only when silicified and they have spatial relations with Artisanal Mining Sites (AMS) within the Kenieba area. This study shows the efficiency of electromagnetic methods to characterize Birimian structures in relation to the gold mineralization in Kedougou-Kenieba Inlier (KKI).

Keywords

• applied geophysics
• electromagnetic methods
• gold exploration
• Birimian structures
• West African Craton (WAC)
• Western Mali