Contents lists available at ScienceDirect Palaeogeography, Palaeoclimatology, Palaeoecology journal homepage: www.elsevier.com/locate/palaeo Benchtop μXRF as a tool for speleothem trace elemental analysis: Validation, limitations and application on an Eemian to early Weichselian (125–97 ka) stalagmite from Belgium Stef Vansteenberge a , Niels J. de Winter a, ⁎ , Matthias Sinnesael a,c , Zhao Xueqin b , Sophie Verheyden a , Philippe Claeys a a Department of Analytical Chemistry, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium b Institute of Environment and Resources, Southwest University of Science and Technology, 621010 Mianyang, China c Department of Geology, Ghent University, Ghent, Belgium ARTICLE INFO Keywords: X-ray fluorescence Speleothem Trace elements Paleoclimate Last interglacial ABSTRACT Variations of trace element (e.g. Mg, Sr, Ba, Fe, Zn etc.) concentrations along a speleothem's growth axis con- stitute important paleoclimate proxies. The use of laboratory micro X-ray fluorescence spectrometry as a fast and cheap alternative for conventional mass spectrometry techniques for trace element analysis on speleothems has been explored in the past and yielded satisfactory results. However, within the speleothem community there is need for an in-depth investigation of the full potential of this analytical technique. Compared to other types of paleoclimate archives, benchtop (μ)XRF analysis on speleothems is analytically more challenging because of the high-crystalline speleothem matrix and the low abundance of the elements of interest. In this study, several speleothem samples with differences in mineralogy (calcite versus aragonite) and composition are investigated. Various instrumental parameters are tested and recommendations are made for future studies applying (μ)XRF analysis to speleothems. Quantification based on a multiple standard calibration and an assessment of the error is carried out. Through validation with mass spectrometry techniques, it is confirmed that benchtop μXRF de- vises are able to generate speleothem trace element records. Successful results were obtained for Sr, Mg and Fe, while Zn and Ba were quantified in samples characterized by high concentrations. Nevertheless, caution has to be taken when interpreting the results, due to the presence of diffraction caused by the crystallinity of the samples. The elements which provide reliable results are sample specific and depend on the type of matrix and elemental abundance. These findings are applied on an Eemian to early Weichselian stalagmite from the Han- sur-Lesse Cave, Belgium. Time series were constructed for Mg and Sr, creating a multiproxy dataset together with previously obtained stable isotope (δ 13 C and δ 18 O) ratios, growth-rate and stalagmite morphology. It appears that Mg and Sr are not primarily controlled by prior calcite precipitation, but rather by changes in vegetation activity above the cave. 1. Introduction Speleothems constitute one of the most important continental pa- leoclimate archives and their use has been proven successful in nu- merous paleoclimate reconstructions (e.g. Bar-Matthews et al., 1999; Wang et al., 2001; Genty et al., 2003; Verheyden et al., 2008a; Boch et al., 2011, Van Rampelbergh et al., 2015; Vansteenberge et al., 2019a). Besides the well-established δ 13 C and δ 18 O stable isotope ratio proxies (McDermott, 2004; Lachniet, 2009; Wong and Breecker, 2015), variations in trace element concentrations along the speleothem growth axis also yield crucial information about diverse climate-controlled processes (Fairchild et al., 2000; Verheyden et al., 2000; Fairchild et al., 2006; Fairchild and Treble, 2009; Wynn et al., 2014). For instance, variations in bedrock-derived (alkaline earth) elements such as mag- nesium (Mg), strontium (Sr) and barium (Ba) have been attributed to changes in prior calcite precipitation (PCP). PCP is defined as the pre- cipitation of calcite upstream of the site of speleothem deposition. These changes are directed by drip water availability and therefore primarily reflect changes in the amount of local meteoric precipitation (Fairchild et al., 2000). This effect is even observed on a seasonal scale (Johnson et al., 2006; Jamieson et al., 2016; Vansteenberge et al., 2019b). Concentrations of other trace elements, for instance https://doi.org/10.1016/j.palaeo.2019.109460 Received 15 November 2017; Received in revised form 23 October 2019; Accepted 12 November 2019 ⁎ Corresponding author. E-mail addresses: stef.vansteenberge@vub.be (S. Vansteenberge), niels.de.winter@vub.be (N.J. de Winter). Palaeogeography, Palaeoclimatology, Palaeoecology 538 (2020) 109460 Available online 18 November 2019 0031-0182/ © 2019 Elsevier B.V. All rights reserved. T