A New LA‐ICP‐MS Method for Ti in Quartz: Implications and Application to High Pressure Rutile‐Quartz Veins from the Czech Erzgebirge
A New LA‐ICP‐MS Method for Ti in Quartz: Implications and Application to High Pressure Rutile‐Quartz Veins from the Czech Erzgebirge
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DOI：
10.1111/ggr.12132
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发表时间：
2017-03
影响因子：
3.8
通讯作者：
A. Cruz‐Uribe;R. Mertz‐Kraus;T. Zack;M. Feineman;G. Woods;Dorrit E. Jacob-
中科院分区：
文献类型：
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作者：
A. Cruz‐Uribe;R. Mertz‐Kraus;T. Zack;M. Feineman;G. Woods;Dorrit E. Jacob-
通过实验确定压力和温度对石英中Ti溶解度的控制，为石英中Ti（TitaniQ）地质温度计提供了适用于高达~ 20 kbar地质条件的校准。我们提出了一种新的方法，用于测定石英中的48 Ti质量分数的LA-ICP-MS在1 μg g-1的水平，相关的石英在HP-LT晶体。我们认为，天然石英，如Bishop凝灰岩石英的低CL边缘（通过EPMA测定; 41 ± 2 μg g−1 Ti，2s）比NIST参考玻璃更适合作为低Ti质量分数的参考材料，因为基质效应有限，避免了Ca同量异位素干扰，并且质量48处的多原子干扰不显著，因此允许使用48 Ti作为归一化质量。来自捷克厄尔士山脉的低温石英的33次分析的平均钛质量分数为0.9 ± 0.2 μg g−1（2s），使用48 Ti作为标准化质量，Bishop Tuff石英边缘作为参考材料。48 Ti单个分析的2s平均分析不确定度为8%（50 μm点）和7%（100 μm点），这比使用49 Ti作为分析物产生的21-41%不确定度（2s）提供了更高的准确度。
Experimental determination of the pressure and temperature controls on Ti solubility in quartz provides a calibration of the Ti‐in‐quartz (TitaniQ) geothermometer applicable to geological conditions up to ~ 20 kbar. We present a new method for determining 48Ti mass fractions in quartz by LA‐ICP‐MS at the 1 μg g−1 level, relevant to quartz in HP‐LT terranes. We suggest that natural quartz such as the low‐CL rims of the Bishop Tuff quartz (determined by EPMA; 41 ± 2 μg g−1 Ti, 2s) is more suitable than NIST reference glasses as a reference material for low Ti mass fractions because matrix effects are limited, Ca isobaric interferences are avoided, and polyatomic interferences at mass 48 are insignificant, thus allowing for the use of 48Ti as a normalising mass. Average titanium mass fraction from thirty‐three analyses of low temperature quartz from the Czech Erzgebirge is 0.9 ± 0.2 μg g−1 (2s) using 48Ti as a normalising mass and Bishop Tuff quartz rims as a reference material. The 2s average analytical uncertainty for individual analyses of 48Ti is 8% for 50 μm spots and 7% for 100 μm spots, which offers much greater accuracy than the 21–41% uncertainty (2s) incurred from using 49Ti as an analyte.