Data to: Molybdenum and titanium isotopic signatures of arc-derived cumulates

Along with the isotope data, also bulk rock major and trace elements as well as in-situ microprobe data of individual minerals were measured. The cumulates and mafic enclaves exhibit Ti isotopic compositions ranging from that of arc-basalts/andesites to significantly lighter values (δ49Ti between −0.15 and + 0.08‰), which is in agreement with a Rayleigh distillation model.

The δ49Ti correlates negatively with the abundance of Fe-Ti oxides, suggesting that in samples which have δ49Ti signatures similar to those of arc-basalts, most of the Ti is hosted in pyroxene and amphibole. This indicates that the degree to which Ti isotopes are fractionated in a melt is controlled by the fraction of Ti incorporated into silicate phases versus that incorporated into Fe-Ti oxides. In contrast, the corresponding Mo isotopic compositions of the upper crustal magmatic cumulates and mafic enclaves are more dispersed (δ98MoNIST = −0.02 ± 0.22‰, 2 s.d.) and similar to average arc-basalts.