What Can We Learn From X‐Ray Fluorescence Core Scanning Data? A Paleomonsoon Case Study

Abstract

X‐ray fluorescence (XRF) core scanning of marine and lake sediments has been extensively used to study changes in past environmental and climatic processes over a range of timescales. The interpretation of XRF‐derived element ratios in paleoclimatic and paleoceanographic studies primarily considers differences in the relative abundances of particular elements. Here we present new XRF core scanning data from two long sediment cores in the Andaman Sea in the northern Indian Ocean and show that sea level related processes influence terrigenous inputs based proxies such as Ti/Ca, Fe/Ca, and elemental concentrations of the transition metals (e.g., Mn). Zr/Rb ratios are mainly a function of changes in median grain size of lithogenic particles and often covary with changes in Ca concentrations that reflect changes in biogenic calcium carbonate production. This suggests that a common process (i.e., sea level) influences both records. The interpretation of lighter element data (e.g., Si and Al) based on low XRF counts is complicated as variations in mean grain size and water content result in systematic artifacts and signal intensities not related to the Al or Si content of the sediments. This highlights the need for calibration of XRF core scanning data based on discrete sample analyses and careful examination of sediment properties such as porosity/water content for reliably disentangling environmental signals from other physical properties. In the case of the Andaman Sea, reliable extraction of a monsoon signal requires accounting for the sea level influence on the XRF data.

Isolating Detrital and Diagenetic Signals in Magnetic Susceptibility Records From Methane‐Bearing Marine Sediments

“…We utilize Zr/Rb elemental ratios from XRF core scanning as a proxy for the detrital heavy mineral content of the sediments, which is highly correlated with κ along the eastern margin of peninsular India (Phillips, Johnson, Giosan, & Rose, 2014). Zr/Rb has been used as a grain size proxy (e.g., Chen et al., 2006; Dypvik & Harris, 2001; Gebregiorgis et al., 2020; Toyos et al., 2020) due to the enrichment of Zr in sediment coarse fractions. However, the relationships between Zr/Rb and grain size is not always consistent in marine sediments, especially in fine‐grained sediments with limited coarse, detrital fraction (Phillips, Johnson, Giosan, & Rose, 2014; Wu et al., 2020).…”

Factors driving sediment compositional change in the distal area of the Ria de Vigo (NW Spain): oceanographic processes vs. paleopollution

“…6 (II)) and the correlations presented in Appendix 7 show that Y-EF is associated with the enrichment of several other chemical elements (La-EF, Ce-EF, Pr-EF, Th-EF, Y-EF, Rb-EF, Nd-EF, Sm-EF, Zr-EF, Na-EF, Ti-EF, Gd-EF, K-EF, Hf-EF, Mg-EF, Ta-EF, U-EF, Tb-EF, Dy-EF, Nb-EF, Er-EF, Lu-EF, Cs-EF, Yb-EF, Cd-EF, Eu-EF, Mo-EF, Ho-EF, Be-EF, Ba-EF, Sn-EF, P-EF, Mn-EF, W-EF), as well as the ratios La/Sc, Th/Sc, and Th/Co. Therefore, the ratios Ti/Ca, Fe/Ca, and Mg/Ca can be considered good tracers of the lithogenic influx relative to the biogenic influx (Gebregiorgis et al 2020;Nace et al 2014).…”

Integrated Methodological Approach for the Documentation of Marine Priority Habitats and Submerged Antiquities: Examples from the Saronic Gulf, Greece

“…This can be achieved by using X-ray fluorescence (XRF) core scanning. XRF counts the major and trace elements, and by calculating the ratios of different elements, it is possible to understand the paleoclimatic factors that affected the environment over a great timescale [107].…”