Fig. 3
Comparison of europium isotopic signatures for the magnitude of Eu anomaly ([Eu]N/[Eu*]N). The blue line represents a correlation between the degree of δ153Eu and the magnitude of the Eu anomaly. The blue line was plotted including the Eu isotope ratio of rhyolite reported by Lee et al.4. The yellow band indicates the mean repeatability of Eu isotope ratio of NIST3117a Eu standard reagent within error range of ± 0.05‰ (2SD) during 2018–2024 (see Supplementary Table S3 and Fig. S7). Note the values of δ153Eu and positive Eu anomalies ([Eu]N/[Eu*]N > 1) from Ulleung Island mafic volcanic rocks. ([Eu]N/[Eu*]N = normalized values of Eu in the sample/interpolated value between the normalized value of Sm and Gd, i.e., [Eu]N. The REE concentration was normalized by the REE concentration of C-chondrite40. The147Sm-149Sm isotope pair in this work was used to perform bracketed mass bias correction (C-SSBIN) for determining and comparing Eu isotopic ratio (δ153Eu) in various kinds of geological materials7.
