High-precision laser ablation U-Pb geochronology using a Neptune PLUS equipped with two 1013 Ω amplifiers: Age mapping of Jack Hills detrital zircon

An all-Faraday laser ablation U-Pb geochronology method using a Neptune PLUS MC-ICPMS and utilizing two 10 13 Ω amplifiers is presented. Using laser conditions and sample volumes similar to those of single collector studies, we measure accurate (~0.1%) and precise (<0.1 to 0.2%) 207 Pb/ 206 Pb dates in ancient zircon, while 206 Pb/ 238 U offers accuracy and precision of better than 1.5% in the Phanerozoic and Neoproterozoic zircon analyzed here. This approach negates the need for the complicated detector-cross calibrations of previous LA-MC-ICPMS methods, as well as deadtime corrections associated with secondary electron multipliers, while still taking advantage of substantial improvement in precision offered by multi-collection. The updated LA-MC-ICPMS approach is applied to both mapping and spot analyses of Hadean detrital zircon from the Jack Hills metaconglomerate (Western Australia). The results demonstrate the advantages of the significant improvements in precision offered by 10 13 Ω amplifiers and highlight the complex behavior of U-Pb isotope systematics resulting from multiple episodes of Pb-loss in this highly significant archive of Earth's earliest history. This approach is expected to provide a significant advance in the precision and accuracy of in-situ measurement of ancient mineral geochronometers like zircon, baddeleyite, monazite, cassiterite, xenotime, titanite, and apatite.