Synthetic zircon doped with hafnium and rare earth elements: A reference material for in situ hafnium isotope analysis
Synthetic zircon doped with hafnium and rare earth elements: A reference material for in situ hafnium isotope analysis
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DOI：
10.1016/j.chemgeo.2011.04.013
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发表时间：
2011-06-26
期刊：
影响因子：
3.9
通讯作者：
Lam, Rebecca
中科院分区：
文献类型：
--
作者：
Fisher, Christopher M.;Hanchar, John M.;Lam, Rebecca
制备了一系列掺Hf和稀土元素（REE）的助熔剂法合成锆石晶体，并将其用作锆石Lu-Hf同位素原位激光烧蚀多接收电感耦合等离子体质谱（LA-MC-ICPMS）分析的参考物质。对合成锆石晶体进行掺杂，以产生大范围的REE/Hf，从而允许监测和校正有时大的Yb-176和Lu-176对天然锆石中低丰度Hf-176的同量异位素干扰以及来自Gd、Tb和Dy的潜在氧化物干扰的稳健手段。合成的锆石晶体具有均匀的Hf同位素组成，在晶粒内和晶粒之间，如通过溶液MC-ICPMS分析从来自三种不同合成的锆石的多个碎片中化学分离的Hf所记录的，以及在两个不同实验室中进行的321激光烧蚀MC-ICPMS分析。另外110个天然锆石晶体的原位分析揭示了相同的天然和合成锆石的Hf同位素分析过程中的激光烧蚀行为。因此，合成锆石晶体提供了在地质研究的常规同位素分析期间监测宽范围Yb和Lu干扰（在质量176处高达总信号强度的50%）的手段。它们也可能有助于开发改进的实验室协议，以准确的天然锆石的Lu-Hf同位素原位测量。本数据说明了Yb-176干扰校正对Hf-176的重要性，如果不适当地应用于具有可变且通常高Yb-176/Hf-177的天然样品，则可能导致大的偏差。这项研究明确表明，使用高稀土元素/铪合成锆石标准校准的Yb质量偏差校正比使用Yb掺杂的天然铪解决方案更准确。最后，本工作的结果表明，合成矿物可能被证明是有用的原位方法开发工具和同位素参考材料。(c)2011爱思唯尔有限公司版权所有。
A series of flux-grown synthetic zircon crystals doped with Hf and selected rare earth elements (REE) were produced for use as a potential reference material for Lu-Hf isotopic analysis of zircon by in situ laser ablation multi-collector inductively-coupled plasma mass spectrometry (LA-MC-ICPMS). The synthetic zircon crystals were doped such as to produce a large range of REE/Hf, allowing for a robust means of monitoring and correcting the sometimes large Yb-176 and Lu-176 isobaric interferences on the low-abundance Hf-176 in natural zircon, as well as potential oxide interferences from Gd, Tb, and Dy. The synthetic zircon crystals have a homogeneous Hf isotopic composition, both within and between grains, as documented by solution MC-ICPMS analyses of Hf chemically separated from multiple fragments of zircon from three different syntheses, and 321 laser ablation MC-ICPMS analyses done in two different laboratories. An additional 110 in situ analyses of natural zircon crystals reveal identical behavior of natural and synthetic zircon during Hf isotope analysis by laser ablation. Hence, the synthetic zircon crystals provide a means of monitoring a wide range of Yb and Lu interferences (up to 50% of the total signal intensity at mass 176) during routine isotopic analysis for geological studies. They also may be helpful in developing improved laboratory protocols for accurate in situ Lu-Hf isotopic measurement of natural zircon. The present data illustrate the importance of the Yb-176 interference correction on Hf-176, which can result in large biases if not properly applied to natural samples with their variable and often high Yb-176/Hf-177. This study definitively shows that use of high-REE/Hf synthetic zircon standards for calibrating the Yb mass bias correction is more accurate than use of Yb-doped natural Hf solutions. Finally, the results of the present work suggest that synthetic minerals may prove useful as both in situ method development tools and isotopic reference materials. (c) 2011 Elsevier B.V. All rights reserved.