LA-ICP-MS multi-pulse short time ablation method for ultra-thin rings of zircon
Zircon is a robust dating accessory mineral,and often develop thin ring(generally less than 5 μm),which poses challenges to obtaining accurate ages of this ring.This article conducted a series of comparative and experimental studies from three aspects:① sample preparation methods;② experimental conditions,and ③ data algorithms to evaluate the reliability of multi-pulse short time ablation method for LA-ICP-MS U-Pb dating of ultra-thin ring(～1 μm)in natural zircons.The results showed that although the double-sided adhesive sample prepara-tion method is fast,the sample observation under microscopic and laser system are poor.The resin-fixed prepara-tion method has high efficiency,is easy to observe with transmitted light and reflected light,and is conducive to sample surface focusing.For laser setting parameters,data results in 5 Hz/2 s ablation are more stable than those in 10 Hz/1s ablation.The peak integration method is superior to linear regression and mean value methods for data re-duction.Our results show that by using rapid erosion method for Plesovice and Qinghu zircon dating are consistent with the recommended values within the error range,but the data error is relatively large(～5％,1σ).The zircon standards Plesovice and Qinghu are improved by 3％and 2％respectively when the 50％～60％of each signal peak value peak integration method was used.The combination of resin-fixed sample preparation,peak integration data processing method and multi-pulse short time ablation method can get an acceptable age of ultra-thin zircon ring.This method can provide more age constraints for multi-age geological processes.
ultra-thin ring in zirconmulti-pulse short time ablation methodsample preparation methodpeak ar-ea integration methodU-Pb dating
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