Ban‐1 Zircon: A New Natural Zircon Reference Material for LA‐MC‐ICP‐MS Zr and Hf Isotopic Determinations

Abstract

New zircon reference materials for in situ zircon radiogenic Hf isotope and stable Zr isotopic determinations made by laser ablation multi-collector inductively coupled plasma-mass spectrometry (LA-MC-ICP-MS) are required due to high data productivity and consequently high reference material consumption rate. This study examines a new natural zircon for Zr isotope ratios by double spike thermal ionisation mass spectrometry (TIMS), and for Hf isotopes by bulk solution nebuliser (SN)-MC-ICP-MS with both Zr and Hf determined by LA-MC-ICP-MS. A total of five zirconium isotope measurements from drilled zircons, determined by TIMS, yield a mean δ 94/90 Zr IPGP-Zr value of -0.09 AE 0.06‰ (2s). Five and eight hafnium isotope measurements for powders from the drilled zircons and Ban-1-4 by SN-MC-ICP-MS, yield mean 176 Hf/ 177 Hf ratios of 0.282985 AE 0.000011 (2s) and 0.282982 AE 0.000007 (2s), respectively. The mean δ 94/90 Zr IPGP-Zr value and 176 Hf/ 177 Hf ratio determined by LA-MC-ICP-MS analyses are -0.06 AE 0.09‰ (2s, n = 504) and 0.282985 AE 0.000035 (2s, n = 327), respectively. The isotopic homogeneities suggest that the Ban-1 zircon is a suitable reference material for microbeam Zr and Hf isotopic measurements.

A community-led calibration of the Zr isotope reference materials: NIST candidate RM 8299 and SRM 3169

“…Because of the rapid expansion of the Zr isotope system, multiple Zr isotope standards have been proposed, in particular for the characterization of mass-dependent effects, such as the SRM 3169 (ref. 26, 29–35), the candidate RM 8299 presented herein, 7–9,11,12,36–38 a single-element Zr solution from PlasmaCal (SCP Science) also known as the IPGP-Zr standard, 5,6,10,11,30,33,35,38–46 and the NRC ZIRC-1 (ref. 44, 47 and 48).…”

“…Because of the rapid expansion of the Zr isotope system, multiple Zr isotope standards have been proposed, in particular for the characterization of mass-dependent effects, such as the SRM 3169 (ref. 26,[29][30][31][32][33][34][35], the candidate RM 8299 presented herein, [7][8][9]11,12,[36][37][38] a single-element Zr solution from PlasmaCal (SCP Science) also known as the IPGP-Zr standard, 5,6,10,11,30,33,35,[38][39][40][41][42][43][44][45][46] and the NRC ZIRC-1 (ref. 44, 47 and 48).…”

Linking Significant Zr Isotopic Fractionation in Magmatic Zircons With Petrographic Textures

“…The lower α zircon‐melt is consistent with the expectation that isotopically light Zr favorably populates 8‐fold coordinated sites in zircon relative to silicate melts with lower coordination (Young et al., 2015). Besides, several natural zircon megacrysts (e.g., Mud Tank) display homogeneous Zr isotopes, implying that zircon crystallization could not drive Zr isotopic fractionation in special systems (e.g., He et al., 2021; Hu et al., 2021; Huang et al., 2021; Tompkins et al., 2020; Xie et al., 2022). These contrasting Zr isotopic fractionation behavior in different magmatic zircons is hard to explain by Rayleigh equilibrium fractionation.…”