Oxygen Isotopic Exchange Between CO2 and Phosphoric Acid: Implications for the Measurement of Clumped Isotopes in Carbonates
Oxygen Isotopic Exchange Between CO2 and Phosphoric Acid: Implications for the Measurement of Clumped Isotopes in Carbonates
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DOI：
10.1029/2019gc008209
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发表时间：
2019-07
期刊：
影响因子：
3.7
通讯作者：
P. Swart;S. Murray;P. Staudigel;D. Hodell
中科院分区：
文献类型：
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作者：
P. Swart;S. Murray;P. Staudigel;D. Hodell
已经进行了实验，其中具有不同C和O同位素组成以及随机和非随机Δ47值的CO2气体被允许在25 ° C和90 °C的温度下在不同尺寸的反应容器中与两种浓度的磷酸平衡。CO2和磷酸之间的13C18O和18O交换速率随暴露时间、反应容器体积、酸强度以及CO2的初始Δ47和δ18O值与理论平衡值的差异而变化。加热的不锈钢表面也会改变Δ47值，例如在基尔器械和其他制备系统中发现的那些。这些结果已被用来解释不同工作者报告的方解石在25 ° C和90 °C之间的分馏差异的变化，以及温度和不同温度（25 ° C和90 °C）下反应样品产生的Δ47值之间的斜率差异。
Experiments have been conducted in which CO2 gases with varying C and O isotopic compositions and with stochastic and nonstochastic Δ47 values have been allowed to equilibrate with phosphoric acid of two concentrations in reaction vessels of varying dimensions at temperatures of 25 and 90 °C. Rates of 13C18O and 18O exchange between the CO2 and the phosphoric acid varied as a function of the length of exposure, volume of reaction vessel, acid strength, and difference of the initial Δ47 and δ18O values of the CO2 from theoretical equilibrium values. The Δ47 values were also altered by heated stainless steel surfaces such as those found within the Kiel device and other preparation systems. These results have been used to explain variations in the differences in the fractionation between 25 and 90 °C reported for calcite by different workers as well as differences in the slopes between temperature and Δ47 values produced by reacting samples at different temperatures (25 and 90 °C).