LKZ-1: A New Zircon Working Standard for the In Situ Determination of U–Pb Age, O–Hf Isotopes, and Trace Element Composition

• Published in: Minerals (Basel) 2019-05, Vol.9 (5), p.325
• Main Authors: Cheong, Albert Chang-sik, Jeong, Youn-Joong, Lee, Shinae, Yi, Keewook, Jo, Hui Je, Lee, Ho-Sun, Park, Changkun, Kim, Nak Kyu, Li, Xian-Hua, Kamo, Sandra L.
• Format: Article
• Language: English
• Subjects: Ablation; Age; Earth; Geology; Hf isotopes; Isotopes; Laboratories; Lasers; LKZ-1; Mass spectrometry; O isotopes; Radiometric dating; Ratios; Reference materials; Scientific imaging; Software; trace element; Trace elements; U–Pb age; working standard; Zircon
• ISSN: 2075-163X; 2075-163X
• DOI: 10.3390/min9050325

This study introduces a new zircon reference material, LKZ-1, for the in situ U–Pb dating and O–Hf isotopic and trace element analyses. The secondary ion mass spectrometric analyses for this gem-quality single-crystal zircon yielded a weighted mean 206Pb/238U age of 572.6 ± 2.0 Ma (2σ, n = 22, MSWD = 0.90), with moderately high U concentrations (619 ± 21 ppm, 1 SD), restricted Th/U ratios (0.146 ± 0.002, 1 SD), and negligible common Pb content (206Pbc < 0.2%). A comparable 206Pb/238U age (570.0 ± 2.5 Ma, 2σ) was produced by the isotope dilution-thermal ionization mass spectrometry. The secondary ion mass spectrometric and laser ablation-assisted multiple collector inductively coupled plasma mass spectrometer analyses respectively showed that LKZ-1 had little variation in O (δ18OV-SMOW = 10.65 ± 0.14‰; laser fluorination value = 10.72 ± 0.02‰; 1 SD) and Hf (176Hf/177Hf = 0.281794 ± 0.000016, 1 SD) isotopic compositions. LKZ-1 was also fairly homogeneous in its chemical composition (RSD of laser ablation ICPMS data ≤ 10%), displaying a relatively uniform chondrite-normalized rare earth element pattern ((Lu/Gd)N = 31 ± 3, Eu/Eu* = 0.43 ± 0.17, Ce/Ce* = 44 ± 32; 1 SD). These consistencies suggest that the LKZ-1 zircon is a suitable working standard for geochronological and geochemical analyses.