Mineralogical and geochemical assessment of Adwa Axum clay deposits Northern Ethiopia industrial potential and genesis

Abstract The Adwa–Axum clay deposits in northern Ethiopia have been traditionally used for pottery, but a comprehensive assessment of their genesis and industrial potential has been lacking. This study examines the mineralogical and geochemical properties of Adwa–Axum clay deposits, central Tigray, northern Ethiopia, to assess their origin and suitability for industrial applications. The mineralogical composition of selected clay samples was determined using X-ray diffraction (XRD), and their chemical composition was analyzed using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES). The XRD analysis revealed a mineral assemblage including kaolinite, smectite, quartz, feldspars (plagioclase, K-feldspar), micas (muscovite, phengite), iron oxides (hematite), and polymorphs (nacrite, dickite). Geochemically, the clays are characterized by a depletion of transition elements, large-ion lithophile elements, and high-field-strength elements, alongside moderate Fe₂O₃, low loss on ignition (LOI), and low combined alkali (Na₂O + K₂O) contents. The integration of these mineralogical and geochemical signatures, as well as the discrimination on a Ce + Y + La vs. Ba + Sr plot, indicates that the deposits formed through a combination of supergene (in-situ weathering) and hypogene (hydrothermal alteration) processes. These properties suggest high potential for ceramics and refractories, and conditional suitability for paper and paint production. However, the relatively high iron oxide and feldspar contents are identified as impurities that could limit specific high-value applications. This study concludes that the Adwa–Axum clay deposits are a valuable industrial resource whose economic viability is enhanced through beneficiation to meet international material standards.