Mineral Geochemical Implications in the Thermo-Barometric Conditions and Petrogenesis of the Bougouni Plutonic Complex, in Southern Mali (Léo-Man Shield, West African Craton)

Abstract

The Bougouni Pegmatite Province is recognized as the largest in west Africa. It comprises lithium-bearing pegmatites, which are associated with Paleoproterozoic rock lithology of Bougouni unit. In west Africa, the Paleoproterozoic rocks show alternation between metasedimentary units, greenstone belt and intrusive plutons. Plutonic intrusions are well distributed across the Léo-Man Shield and essential for understanding the evolution of Paleoproterozoic crust. This study highlight new petrographic and minerals chemical data of Bougouni unit. In this Unit,the metasedimentary rocks comprise two main types of metasedimentary sequence: coarse-grained (metagreywacke, schist and conglomerate) and fine-grained (siltstones and argillites). The Bougouni plutonic complex comprises a wide variety of rocks, range from diorite to two-mica monzogranites. They contain calcic amphibole, magnesium-rich biotite, plagioclase (albite to labrador), alkali feldspar (perthite, microcline), quartz, primary muscovite, and accessory minerals (e.g., titanite, magnetite, epidote, apatite, zircon etc.) in varying proportions.