Variations of trace element (e.g. Mg, Sr, Ba, Fe, Zn etc.) concentrations along a speleothem's growth axis constitute
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 devises
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 (δ⁠13C andδ⁠18O) 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.
Original languageEnglish
Article number109460
Pages (from-to)1-18
Number of pages18
JournalPalaeogeography, Palaeoclimatology, Palaeoecology
Issue numberXXX
Publication statusPublished - 27 Nov 2019

ID: 48366387