MINERALOGICAL AND PETROGRAPHIC ANALYSIS OF KASIYA FLAKE GRAPHITE ORE

This study presents a comprehensive mineralogical and petrographic investigation of flake graphite from the Kasiya deposit, integrating thin section microscopy, X-ray fluorescence (XRF), Inductively coupled plasma-optical emission spectrometry (ICP-OES), and general chemical analysis. Petrographic analysis revealed a mineral assemblage dominated by graphite, quartz, feldspar, muscovite and chlorite, with graphite occurring as a disseminated flakes aligned along foliated planes. Textural features such as recrystallized quartz mosaics and chlorite overgrowths provide compelling evidence for metasomatic alteration. Elemental geochemical data highlight the presence of mobile ions such as Fe, Al, Na, Ca, and K, further confirming fluid-driven metasomatic processes. This study also established a correlation between graphite flake size and grade, with samples exhibiting large flakes corresponding to higher graphite concentrations. The origin of metasomatism is interpreted to be associated with CO2- and H2O-rich metamorphic fluids, possibly linked to regional tectonothermal events. These findings enhance the formation mechanism of graphite in high-grade metamorphic terranes and provides valuable insights for resource evaluation and beneficiation strategies.

This study presents a comprehensive mineralogical and petrographic investigation of flake graphite from the Kasiya deposit, integrating thin section microscopy, X-ray fluorescence (XRF), Inductively coupled plasma-optical emission spectrometry (ICP-OES), and general chemical analysis. Petrographic analysis revealed a mineral assemblage dominated by graphite, quartz, feldspar, muscovite and chlorite, with graphite occurring as a disseminated flakes aligned along foliated planes. Elemental geochemical data highlight the presence of mobile ions such as Fe, Al, Na, Ca, and K, further confirming fluid-driven metasomatic processes. This study also established a correlation between graphite flake size and grade, with samples exhibiting large flakes corresponding to higher graphite concentrations.

The geological framework of Lilongwe, Mchinji, and Upper Bua is primarily defined by the Precambrian Basement Complex, which consists of ancient metamorphic and igneous rocks that have undergone extensive deformation and weathering over millions of years (Bloomfield, 1965; Carter & Bennett, 1973). These regions form part of Malawi’s cratonic shield, characterized by deep-seated metamorphism and magmatic intrusions associated with prolonged tectonic activity. The dominant rock types include gneisses, schists, and granites, which reflect a complex geological history involving tectonic compression, high-grade metamorphism, and episodic magmatism. Over time, prolonged weathering under tropical conditions has contributed to the formation of extensive lateritic profiles, particularly in Lilongwe and Upper Bua, where iron-rich soils and potential bauxite deposits are present (Freyberg, 1966). Furthermore, the influence of fluvial activity along river valleys, such as the Bua River, has resulted in the deposition of alluvial sediments, modifying the geomorphology of the region.

Traditional authority: TA Chiseka

District: Lilongwe

Coordinates: -14.3432, 33.6234