Application of hand-held X-ray fluorescence spectrometry in the core analysis of Paleogene lacustrine shales in the Jiyang Depression

Lacustrine sedimentary facies vary rapidly in rift basins in China, exhibiting significant heterogeneity in shale fabric and chemical composition. In order to characterize the heterogeneity effectively, the analysis of closely spaced geological samples is required to obtain such data as element geochemistry. We employed the technique of X-ray fluorescence spectral analysis (XRF) to study core samples systematically collected from the mudstone/shale section of the third and fourth members of the Eocene Shahejie Formation in the Jiyang Depression, and optimized the experiment conditions of core testing conducted using a hand-held X-ray fluorescence spectrometer. Subsequently, this method was tested with selected shale and sandstone samples to determine the XRF response of diverse lithologies. Through the closely spaced XRF testing on cores, we determined the element composition and petrologic characteristics of cores. Preliminary applications showed the effectiveness of the technique for determining shale lithology and lithofacies, and thus provided a diagnostic tool for shale heterogeneity characterization.