Strontium–Neodymium isotopic compositions of eighteen geological Chinese reference materials measured on TIMS and MC-ICP-MS

Abstract

This study presents radiogenic Sr–Nd isotopic compositions of eighteen geological Chinese reference materials (RMs) measured on TIMS and MC-ICP-MS independently. These RMs include nine igneous rocks, six sedimentary rocks, two metamorphic rocks, and one fluvial sediment. Among the RMs, eight Nd isotopic ratios and three Sr isotopic ratios of them are first reported. Our results showed that the Sr and Nd isotopic ratios of these RMs measured on TIMS and MC-ICP-MS are consistent within the error range. We also observed that Rb interference can be dramatically reduced using filament burning technique during TIMS measurement, which is significant to achieve accurate Sr isotopic data especially for samples with high Rb content. To evaluate the homogeneity of RMs, Sr and Nd isotopic data reported from various laboratories were clustered together for comparative analysis. Overall, these RMs from various laboratories yielded relatively consistent ratios, except for some anomalies. We concluded that isobaric interference could be probably the main factor that induced the isotopic inconsistency. Therefore, we propose that these RMs are reliable candidates for Sr and Nd isotope analyses. The datasets will play a fundamental role in quality assurance and comparison for radiogenic Sr and Nd isotopic systems.