A geophysically constrained litho-structural analysis of the Eburnean greenstone belts and associated granitoid domains, Burkina Faso, West Africa
Abstract
Interpretation of airborne geophysical data integrated with field structural and lithological observation was successfully employed in the creation of the litho-structural framework in a poorly exposed Paleoproterozoic granite-greenstone terrain of the West African Craton. The geophysical data portray with sufficient detail all of the lithological units and structural features present.
The results suggest that the granitoid domains are formed by numerous small to medium-sized plutons. The existence of several generations of magmatic episodes has a significant impact on the development of a regional tectonic model.
The magnetic data provided a better definition of the actual pluton shapes and several highly magnetic late-orogenic plutons were reliably identified. Relic F1 fold hinges were recognized in the Hounde and Boromo greenstone belts.
The D1 penetrative structures are generally affected by the D2 transcurrent shear zones, which often form as well the granite-greenstone belt boundaries. Previously unreported S2 shear zones including the Bossie shear zone, transecting the Sideradougou granitoid domain and abundant small-scale shear zones affecting all of the lithologies represent prospective areas for gold exploration.
Airborne gamma-ray spectrometry data aided in the mapping process in areas with less regolith cover including erosional ridges and parts of the Banfora greenstone belt. The magnetic data revealed at least three generations of doleritic dykes crosscutting the western Burkina Faso.