Rapid and simultaneous determination of multi-element abundances and U-Pb age for zircon crystal using UV laser ablation ICP-MS technique: critical evaluation of the technique with 91500 zircon standard

Abstract

A new analytical technique for simultaneous determinations of REE, U, Th, Pb abundances and U-Pb age from a single analysis spot of zircon crystal is presented in this paper. It uses ultra-violet (UV)-laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). Coupling of multi-element abundance data and U-Pb age data can provide piercing information for petrogenetic studies of igneous rocks and for provenance studies of sedimentary and metamorphic rocks. The REE, U, Th and Pb abundances and ²⁰⁷Pb/²⁰⁶Pb and ²⁰⁶Pb/²³⁸U ratios for a 91500 zircon standard were simultaneously analyzed in order to test the accuracy of the measurement and to evaluate a homogeneity within a grain of the standard sample. The resulted abundance data for almost of all rare earth elements (REE) show good agreement with those obtained by the secondary ion mass spectrometry (SIMS) and with LA-ICP-MS data. The data obtained in this study fell in the range of published data. Only exception is the abundance data for Er, Lu, Pb and U. These elements are differed largely from the published data beyond the precision of our measurements (∼10% in SD). The large discrepancy between present results and previous authors’ data can be explained by heterogeneity among different grains of the zircon standard. In the case of U-Pb age, resulted ²³⁸U-²⁰⁶Pb and ²⁰⁷Pb-²⁰⁶Pb ages were 1131±152 Ma (2SD) and 1156±132 Ma (2SD), respectively, showing an excellent agreement with the TIMS data within analytical uncertainties achieved in this study (∼20%, 2SD). The abundance data for REE, U, Th and Pb, together with U-Pb isotopic ones demonstrate clearly that the present LA-ICPMS technique can provide a rapid and versatile tool for the multi-element abundances and U-Pb age determinations.