Guidelines for reporting zircon Hf isotopic data by LA-MC-ICPMS and potential pitfalls in the interpretation of these data

Protocrustal evolution of the Nuvvuagittuq Supracrustal Belt as determined by high precision zircon Lu–Hf and U–Pb isotope data

“…Both of these aspects often hamper the validity of the interpretation of data obtained by LA-ICPMS analyses of zircon (e.g. Gerdes and Zeh, 2009;Lenting et al, 2010;Fisher et al, 2014;Guitreau and Blichert-Toft, 2014) and they result mainly from one or a combination of three methodological limitations. The first such limitation is that different volumes of zircon are consumed during the analyses of U-Pb and Lu-Hf thus necessitating assumptions regarding the homogeneity of the two analysed volumes, i.e.…”

“…The third limitation is that the precision and accuracy of LA-MC-ICP-MS Lu-Hf isotope data depend on making the appropriate corrections of large isobaric interferences of 176 Yb and 176 Lu on the low-abundance radiogenic 176 Hf isotope (see e.g. discussions in Griffin et al (2006), Corfu (2007), Blichert-Toft (2008), Guitreau et al (2012) and Fisher et al (2014)). For unknown samples where heterogeneities and differing REE concentrations may be present, corrections for isobaric interferences (that in particular are highly sensitive to mass bias corrections, see discussion in Blichert-Toft (2008)) may lead to a spread in data over several epsilon units that can lead to serious misinterpretation of data.…”

Cathodoluminescence guided zircon Hf isotope depth profiling: Mobilization of the Lu–Hf system during (U)HP rock exhumation in the Woodlark Rift, Papua New Guinea

“…The analytical approach taken in this study builds on the work of Woodhead et al (2004Woodhead et al ( , 2008 who investigated the feasibility of Hf isotope depth profiling in zircon standards and one natural sample via LA-MC-ICP-MS. Their ultimate conclusion was that 'distinct layers can be resolved for realistic ablation conditions', and thus that the technique has great promise. The zircon grains in the two quartzofeldspathic host gneisses from PNG represent an ideal case for Hf isotope depth profiling because they have been documented (Zirakparvar et al, 2014) to contain age and geochemical heterogeneity on a spatial scale well below the typical analytical volume (Fisher et al, 2014) of a single LA-MC-ICP-MS Hf isotope analysis.…”

Evolution of the Jura-Cretaceous North American Cordilleran margin: Insights from detrital-zircon U-Pb and Hf isotopes of sedimentary units of the North Cascades Range, Washington

“…Hafnium-isotope ratios were normalized relative to 176 Hf/ 177 Hf = 0.282482 for Plesovice (Sláma et al, 2008). Data reduction and interference corrections followed the methods outlined in Fisher et al (2011) andFisher et al (2014b Lu decay constant determination of Söderlund et al (2004). The results are shown in Figure 6 and Supplemental Table S2 (see footnote 1).…”

“…The laser fluence was ~7 J/cm 2 with a repetition rate of 10 Hz, ablating a 30-40 µm deep pit. The mass spectrometer gas-flow rates and Faraday-cup configurations for the mass spectrometer followed the param eters described in Fisher et al (2014b). Plesovice ( Hf values for the secondary standards were 0.282180 ± 65 (n = 29) and 0.282010 ± 35 (n = 32), respectively.…”