Geological and Geochemical Characteristics of Quartz-Feldspar Pegmatites in Southern Ethiopia

The Kenticha pegmatite field, located within the Neoproterozoic Adola Belt of Southern Ethiopia, represents one of the most significant rare-element mineral provinces in the East African Orogeny. Tantalum was exploited from weathered regolith before and also produced the huge reserves of feldspar, quartz and lithium from underlying hard-rock bodies. This study presents the geology properties and evaluating economic potential of five major veins (No. 1-5) through a multi-disciplinary approach including field geological mapping, core logging, and geochemical characterization. Major and trace element concentrations were determined using X-ray Fluorescence (XRF) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS), while mineralization phases were defined by X-ray Diffraction (XRD). Geochemical analysis demonstrates that the pegmatites are classified as the Lithium-Cesium-Tantalum (LCT) family and the spodumene subtype, and characterized by extreme magmatic fractionation. Fractionation indices, notably the K/Rb ratio, exhibit a systematic decline from approximately 36 in the granitic wall zones to 19–20 in the highly evolved spodumene-rich upper intermediate zones. Quantitative assessments of industrial mineral quality reveal SiO<sub>2</sub> averages of 67.3% and Al<sub>2</sub>O<sub>3</sub> contents of 17.2%, with subsurface Fe<sub>2</sub>O<sub>3</sub> levels consistently below 0.1%. These values comply with ISO 13006 Group BIa standards for the international glass and porcelain industries. Economic reserve estimations, calculated based on the 1:5000 geological map and strike tracing, assumption 2.7 million tons of high-grade feldspar and 7.2 million tons of quartz. Additionally, the discovery of 87.7 million tonnes of lithium ore at 0.78% Li<sub>2</sub>O underscores the deposit's strategic importance. The report concludes with recommendations for an integrated multi-mineral extraction strategy to drive Ethiopia’s industrialization and green energy supply chain.