GZ7 and GZ8 - Two Zircon Reference Materials for SIMS U-Pb Geochronology.

ABSTRACT: Here, we document a detailed characterisation of two zircon gemstones, GZ7 and GZ8. Both stones had the same mass at 19.2 carats (3.84 g) each; both came from placer deposits in the Ratnapura district, Sri Lanka. The U-Pb data are in both cases concordant within the uncertainties of decay constants and yield weighted mean ²⁰⁶Pb/²³⁸U ages (95% confidence uncertainty) of 530.26 Ma ± 0.05 Ma (GZ7) and 543.92 Ma ± 0.06 Ma (GZ8). Neither GZ7 nor GZ8 have been subjected to any gem enhancement by heating. Structure-related parameters correspond well with the calculated alpha doses of 1.48 × 10¹⁸ g^-1 (GZ7) and 2.53 × 10¹⁸ g^-1 (GZ8), respectively, and the (U-Th)/He ages of 438 Ma ± 3 Ma (2s) for GZ7 and 426 Ma ± 9 Ma (2s

SUBMITTER: Nasdala L 

PROVIDER: S-EPMC6334521 | biostudies-literature | 2018 Dec

REPOSITORIES: biostudies-literature