Comparison and correction of element measurements in lacustrine sediments using X-ray fluorescence core-scanning with ICP-OES method:A case study of Zigetang Co

Abstract

Using an X-ray Fluorescence(XRF) core scanner,chemistry features of bulk sediment can be measured directly which does not destruct sediment surface nor split sediment cores.This method has been potentially and widely applied to core sediment analysis,but little is known about the effects of sediment physical properties on XRF core scanner measurements.Comparison of intensities obtained by XRF and the chemical concentration measured by Inductively Coupled Plasma-Optical Emission Spectroscopy(ICP-OES),indicates effects of physical properties varied from different elements on elemental intensities in the lacustrine sediments of a core from Zigetang Co in the central Tibetan Plateau.Correlation among elements K,Ca,Ti,Cr,Mn,Fe and Sr between the two measurement methods of the XRF and the ICP-OES is high,but the correlation is low for element sulfur.This indicates that XRF measurements for non-metal elements such as sulfur,which has a multi-chemical valence,could be strongly affected by sediment properties.Comparing the ratios between element intensities and concentration,we found that the lower XRF element intensities were related to the amount of water.Using the intensity of Cl as an indicator of water content,the element intensities of K,Ca,Ti and Fe in the core samples were corrected.The correlation coefficients of each pairs of the two datasets among K,Ca,Ti and Fe were significantly raised.These data sets with highly correlations were used to produce a transfer function to relate XRF element intensity with element concentration.Calculated element concentrations from the intensities show only minor differences from concentrations obtained by ICP-OES,indicating XRF core scanners are a very useful tool for measuring element concentration in lacustrine sediments.