A preliminary case study of potential ceramic raw materials in the Aileu area of Timor Leste

The newly independent country of Timor Leste is located in the eastern half of Timor Island (Indonesian archipelago). Geological studies of the country’s mineral resources and extractive activities are practically non-existent. There is evidence of the exploitation of ceramic raw materials at outcrop level and two small brick kilns, nowadays inactive, in the Dili and Aileu areas. Near Aileu, there are light-coloured silt-rich deposits, interpreted as overbank deposits, interbedded with ancient river terraces (post-Pliocene) overlying metamorphic bedrock. These sediments are the subject of this study, which encompassed geological mapping and preliminary characterisation. Tectonically, the area is a graben, preserving alluvium and colluvium deposits. Five channel samples representative of the silt-rich deposits were collected. Semi-quantitative mineralogical analysis shows that the samples are made of illite, quartz and kaolinite clays, with accessory illite/vermiculite interstratified minerals and K-feldspar. The chemical data show agreement with the estimated mineralogical composition. The grain size distribution points to a silt-dominated assemblage. Most samples have a satisfactory extrudability but deficient moulding properties. After firing, the sampled raw materials form a final product with possible ceramic capability for whiteware production.