Ancient mantle plume components constrained by tungsten isotope variability in arc lavas

Analytical techniques utilised in this study are based on W separation procedures described in earlier work (Willbold et al., 2011; Mei et al., 2018; Tusch et al., 2019). We further optimised the W separation procedure for larger sample sizes while maintaining measurement precision and accuracy. Therefore, we devised a new W separation procedure to process up to 6 g of sample material on a three-step ion exchange chromatography. We utilised the precipitation of a W-free fluoride phase during sample digestion, which removed the majority of matrix elements, while quantitatively retaining W. Sample preparation was carried out under metal-free clean laboratory conditions at the University of Göttingen.