Quantitative analysis of shales by KBr-FTIR and micro-FTIR

Fine-grained texture, complex mineralogical composition, and diverse organic matter types cause large heterogeneity of shale, and the resulting analytical challenge can only be met with high-resolution techniques. Quantitative determination of clay minerals, quartz and carbonates, as well as organic matter in shale on a micrometer-scale is demonstrated by traditional KBr-Fourier transform infrared (FTIR) spectroscopy and novel reflectance micro-FTIR techniques, respectively, the latter allowing characterization and mapping of areas as small as 20 × 20 μm. Advantages and limitations of FTIR techniques are discussed mainly with reference to the study of shale, but are relevant also for other fine-grained materials.