Palaeogene Sandstones of the Manika Plateau, DR Congo: Sedimentology, Geochemistry, and Tectonic Implications

Abstract

This study presents an analysis of Paleogene sandstones from the Manika Plateau in Kolwezi, Democratic Republic of Congo. These sandstones are classified in the “Grès polymorphes” group, which, together with the overlying “Sables ocre”, make up the Kalahari Supergroup. The sedimentological study of this sandstone was based on granulometric analysis by sieving, petrographic and morphoscopic analysis using an optical microscope and binocular loupe, and chemical analysis of major and trace elements by optical emission spectrometer (ICP-OES) and mass spectrometry respectively (ICP-MS). The results show that the sandstones are quartz arenites with a high degree of mineralogical, textural and chemical maturity. Sandstones are recycled deposits formed in an intracratonic sedimentary basin within a passive continental margin. They have been transported over long distances by fluvial processes. Initially, these sandstones were derived from intense alteration of felsic magmatic rocks, mainly tonalite-trondhjemite-granodiorite (TTG) complexes, under warm, humid paleoclimatic conditions and oxidizing environments.