Abstract
Mixed-layer kaolinite/smectite minerals constitute the principal clay assemblage in the Quaternary alluvium type red-burning clay resource in Liloan, Cebu, Philippines, based on analytical testworks employing x-ray diffraction (XRD), differential thermal analysis (DTA), thermogravimetry (TG), infrared (IR) absorption spectroscopy, scanning electron microscopy (SEM), and energy dispersive x-ray (EDX) performed on several clay samples obtained from the area. Careful examination of diffraction curves indicate that the main constituent mineral is randomly interstratified kaolinite/smectite. Computer-simulated x-ray diffractograms of the mixed-layer kaolinite/smectite show good agreement with the observed x-ray diagrams in (001) and (002) basal reflections. Calculated values derived from simulation, moreover, illustrate the ratio of kaolinite to smectite to be generally higher at surface horizon but gradually becomes of almost equal proportion at depth. The slight variability in ratio may be linked to the effect or degree of differential weathering. Quartz and feldspar are ubiquitous accessory minerals detected in the non-clay fraction.
