Hafnium isotope ratios

Thirlwall, M.F., and Walder, A.J. (1995) In situ hafnium isotope ratio analysis of zircon by inductively coupled plasma multiple collector mass spectrometry. Chem. Geol. 122, 241-247. 

In 2005, De Laeter discussed the role of isotope reference materials for the analysis of non-traditionaT stable isotopes. At present, no isotopically certified reference materials exist for a large number of elements, including Cu, Zn, Mo and Cd, and it is important that this situation be rectified as soon as practicable. Before the isotopically certified reference materials become available for selected elements, suitable reference materials can be created as a standard if sufficient and reliable isotope data have been obtained by interlaboratory comparisons. For example, the Hf/ Hf isotope ratio was measured using hafnium oxide from Johnson Matthey Chemicals, JMC-475, for hafnium isotope ratio measurements with different multi-collector mass spectrometers (ICP-MS and TIMS) as summarized in Table 8.1. However, no isotope SRM is certified for the element Mo either. Mo isotope analysis is relevant, for example, for studying the isotope fractionation of molybdenum during chemical processes or the isotope variation of molybdenum in nature as the result of the predicted double (3 decay of Zr or 18.26-28 spectroscopically pure sample from Johnson Mattey Specpure is proposed as a laboratory standard reference material if sufficient and reliable isotope data are collected via an interlaboratory comparison. 

Unlike. 208pb/204pb or 2 pb/204pb, which depend on Th/Pb and U/Pb, respectively, 208p 5 /206p]3 reflects the Th/U ratio integrated over the history of the Earth. The existence of global correlations between neodymium, strontium, and hafnium isotope ratios and, and the absence... 

Moreover, they are chemically similar. Both display very limited solubility in water, and differences in chemical behavior are mainly associated with atomic size. Lutetium and hafnium are also refractory elements during nebula condensation, and thus their relative abundance in the Earth are chondritic, however, at the time of writing the value of the bulk Earth Hf/ Hf ratio and the Lu decay constant are being debated (Table 1). Neodymium- and hafnium-isotope ratios in this paper will be expressed as parts per 10 deviations from the bulk Earth values, viz., as s d and sht- Eor example,... 

Xie, Q., and Kerrich, R. (1995). Optimization of operating conditions for improved precision of zirconium and hafnium isotope ratio measurement by inductively coupled plasma mass spectrometry.J. Anal. At. Speclrom. 10(2), 99. 

It has been recognized that the Lu-Hf isotopic system in zircon is a powerful tool for deciphering the evolution of the earth s crust and mantle. " Zircon normally contains 0.5-2 wt % Hf, which results in an extremely low Lu/Hf ratio (" Lu/" Hf < 0.002) and consequently a negligible radiogenic growth of Hf due to the decay of Lu. Therefore, the Hf/" Hf ratio of zircon can be regarded as the initial value at the time when it crystaUized. LA-ICP-MS with a multiple ion collector system has also been employed to study the hafnium isotopic composition of zircon and baddeleyite standards in U-Pb geochronology. °°... 

Isotope Ratios of Strontium, Neodymium, Hafnium, and Lead... 

Radiogenic isotope ratios of OIE are shown on Figure 15. These diagrams display remarkably similar topologies as the respective MORE data shown in Figures 4-6. Strontium isotope ratios are negatively correlated with neodymium and hafnium isotopes, and correlations between strontium, neodymium, and hafnium isotopes and lead... 

Another important observation is that, while strontium, neodymium, and hafnium isotopes all correlate with each other, they form poorer, but still significant, correlations with Pb/ °" Pb (or 20 p, /204p ratios in the Pacific and... 

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