Mechanisms of Emplacement and Position in the Eburnean Orogeny of the Deou Alkaline Pluton (Northern Burkina Faso)

Abstract

The Deou granite belongs to the late granitoid group. Its structures are therefore important for interpreting the emplacement mechanisms and deducing the tectonic regime that prevailed at the end of the Eburnean orogeny. The aim of studying this pluton is to understand the mechanisms that prevailed at the end of the Eburnean orogeny. The petrographic and geochemical study reveals that the Deou granite is an alkaline granite belonging to the A-type. Magnetic susceptibility values show that the pluton is essentially ferromagnetic due to the presence of magnetite. Magnetic fabrications measured in the laboratory show foliations that are always steeply dipping and lineations that are steeply plunging in places. These steeply dipping lineation zones can be interpreted as the magma feed zones par excellence of the pluton. These fabrics are where the plutons are emplaced, since the microstructures observed are essentially magmatic. The fabrications of the Deou alkaline granite obtained from measurements of magnetic susceptibility anisotropy and the various geotectonic diagrams used show that the granite was emplaced in a diapiric context. This suggests anorogenic emplacement. These data confirm the post-orogenic nature of the Deou granite, which did not undergo any major reworking after emplacement.