A Preliminary Appraisal of Seven Natural Zircon Reference Materials for In Situ Hf Isotope Determination

Abstract

There is a growing need for new zircon reference materials for in situ Hf‐isotope analysis by laser ablation‐multicollector inductively coupled plasma‐mass spectrometry (LA‐MC‐ICP‐MS). In this contribution we document the results of a preliminary investigation of seven natural zircons, conducted in order to test their suitability in this regard. Solution MC‐ICP‐MS data on separated Lu and Hf fractions provided reference compositional data while the results of ca. 750 in situ LA‐MC‐ICP‐MS analyses allowed assessment of potential micrometre‐scale heterogeneity. On the basis of these analyses and additional relevant considerations such as availability, size and (Lu)Yb/Hf ratio, we suggest that, of the currently available zircons, Temora‐2 and Mud Tank are most likely to provide robust reference materials for Hf isotope determinations both at the present time and into the future. The former has the advantage of also being well‐characterised for U‐Th‐Pb systematics and suitable for in situ age determination, while the latter is the most readily available and is of very large grain size. Additional materials such as BR266, and 91500, although limited in supply, show more consistent Lu/Hf ratios and are thus of use in monitoring elemental fractionation during ICP‐MS analysis.

Zircon U-Pb and Hf isotopic constraints on the genesis of a post-kinematic S-type Variscan tin granite: the Logrosán cupola (Central Iberian Zone)

“…To evaluate the accuracy and precision of the laser ablation results we have repeatedly analyzed two zircon standards: 91500 and Mud Tank (MT). These reference zircons gave 176 Hf/ 177 Hf = 0.282310 ± 0.000049 (2σ) and 0.282502 ± 0.000044 (2σ), respectively, which are identical to average published values of 0.282306 ± 0.000008 for 91500 and 0.282507 ± 0.000006 for MT (Woodhead and Hergt, 2005 (Bouvier et al, 2008) and the depleted mantle The trace element zircon composition was obtained by laser ablation (LA-ICPMS) at the Natural History Museum of London (NHM, London, UK) using an Agilent 7500CS ICP- Flinter, 1971) allow classifying it as stanniferous granite. Ga and Hf data display trends where more fractionated samples show the lowest contents.…”

Did diamond-bearing orangeites originate from MARID-veined peridotites in the lithospheric mantle?

“…Raw data were reduced using the Iolite software package 64 . Isobaric interferences of 176 Yb and 176 Lu on 176 Hf were assessed and corrected following the procedure described by Woodhead et al 65 Plesovice zircon standard 66 was analysed to correct for instrumental drift, whereas Temora-2 and 91500 zircon references 67 Table 8). On the basis of the results for standards (this session and long term), analytical reproducibility (external precision) for 176 Hf/ 177 Hf is B ± 0.000050 (2 s.d.…”

Zircon U-Pb, Hf and O isotope constraints on growth versus reworking of continental crust in the subsurface Grenville orogen, Ohio, USA

“…Four zircon reference samples were used for data quality control, Plesovice (Sláma et al, 2008), R-33 (Black et al, 2004), FC-1 and Temora (Woodhead and Hergt, 2005;Fisher at al. 2011) …”