TITLE:
Paleoproterozoic Belt/Basins’s Plutonic Masses and Country Rocks: Implications on Lithostructurale Architecture of Kedougou Kenieba Inlier (South-East Senegal and South-West Mali)
AUTHORS:
Mame Codou Ndiaye, Mamadou Ndiaye, Papa Malick Ngom, Abdoulaye Landoure, Alain Nicaise Kouamelan, Andrea Moscariello, Antoine de Haller, Mababa Diagne, Rashid Ali Isdine Dao, Serigne Saliou Sylla, Matar Ndiaye
KEYWORDS:
Paleoproterozoic, Plutonic-Masses, Tectonomagmatic, Arcs, Basins, Belt
JOURNAL NAME:
Journal of Geoscience and Environment Protection,
Vol.13 No.10,
October
30,
2025
ABSTRACT: This study focuses on Paleoproterozoic plutonic masses and their host rocks located within the Mako belt and associated basins. The objective is to identify their implications for the lithological and tectonic structure of the Kedougou-Kenieba Inlier through an approach integrating geological mapping, petrography, structural analysis, geochemistry, geophysics and geochronology. Indeed, the lithostructural and geochemical characterization of the plutonic masses shows that Dioudioukounkou is a peralkaline calc-alkaline granite from a volcanic arc located in an oceanic context of an active compressive margin. The post-orogenic granite of Dioudioukounkou is 385 ppm enriched in light rare earth elements. The metaluminous Koulountou pluton and the peraluminous Tiguida pluton represent island arc granites. Tiguida is syncollisional and associated with a low percentage of light rare earth elements with a LaN/SmN ratio below the detection limit and a Na₂O + K₂O content of 6.89%, which is the highest alkaline content in Sesam. Koulountou is a post-collisional granite marked by an active compressive margin environment. It is enriched in light rare earth elements with a LaN/SmN ratio of 2.55. Tinkoto and Diabba are hosted in tholeiitic and calc-alkaline volcanics intersected by calc-alkaline plutonites. Dioudioukounkou shows a concordant U-Pb age of zircon of 2156.1 Ma ± 5.6 Ma. This age appears to correspond to the phase of major magmatic activity associated with early Eburnean deformation D1 comparable to CiscoW. Tinkoto and Koulountou formed at 2109.3 Ma ± 6.0 Ma and 2106.7 Ma ± 8.1 Ma, respectively. Tinkoto is older and linked to the main CiscoM shear corresponding to D2. Koulountou is linked to the second order structures of CiscoM. The geophysical signatures of high to medium magnetic intensities highlight a succession of tectonovolcanic arcs: the arc in context of an oceanic volcanic arc associated with CiscoW, the arc in context of an island arc associated with CiscoM, the arc in context of a back-arc basin associated with CiscoE or D3, and the arc in context of an intracontinental volcanic arc associated with the CiscoF shear contact of Faleme or D4. The basins are defined in low to medium magnetic zones and correspond to the Diale back-arc basin and the Kofi intracontinental basin. These formations are intersected by the volcanic arc granite of Dioudioukounkou, the island arc granites of Koulountou and Tiguida, the back-arc basin granites of Tinkoto and Saraya, and finally the pluton of the intracontinental basin of Gamaye. The latest lithostructural architecture of the Kedougou-Kenieba inlier highlights the tectonomagmatic complexes of Maco, Sesam, Diabba and Kofi, which constitute the regional substrate enclosing these plutonites. The geodynamic evolution of these complexes is linked to a single magmatic event associated with tectonomagmatic episodes. Diabba, which represents the back-arc basin, shows an overturned funnel-shaped geosynclinal architecture, while the intracontinental Kofi basin reveals an hemigraben configuration opened at the end of late orogenic phase behind the intracontinental Faleme collision arc.