Application of X-ray fluorescence mapping in turbiditic sandstones, Huai Bo Khong Formation of Nam Pat Group, Thailand

Abstract

Changes in hydraulic properties of the flow are reflected in the vertical and/or lateral variation in sedimentary structures. In turbiditic sandstones, common sedimentary structures are grain size grading, planar lamination, and cross-lamination. This research is aimed at applying the advances in non-destructive X-ray fluorescence (XRF) mapping technology to detect various sedimentary structures in sandstones. XRF micro-imaging is able to produce in situ elemental-distribution maps of rock samples. This research applied a statistical technique of discriminant analysis to reduce the dimensionality of the variables in order to determine the key element intensity that can be used as a proxy for the observation of sedimentary structures in turbiditic sandstones. The results suggest that principal component analysis can identify the elements and elemental ratios with high loadings that explain the multivariate data. The sedimentary structures are shown in spatial elemental distribution maps and elemental ratios. The methodology here could be applied to in situ μXRF scans where the observation of sedimentary structures or grain size measurements is inaccessible such as in boreholes.