Clumped Isotope Dataset for Experimental Phosphoric Acid and CO2 Exchange Paper

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).

本研究开展了一系列实验：将碳、氧同位素组成各异，且Δ47值呈随机与非随机分布的二氧化碳（CO₂）气体，与两种浓度的磷酸置于不同规格的反应容器中，于25℃与90℃条件下完成平衡反应。二氧化碳与磷酸之间的¹³C¹⁸O及¹⁸O同位素交换速率，随暴露时长、反应容器容积、酸浓度，以及CO₂初始Δ47、δ¹⁸O值与理论平衡值的差值而变化。此外，加热的不锈钢表面（如凯耳（Kiel）装置及其他样品前处理系统内的不锈钢表面）同样会改变Δ47值。上述实验结果可用于解释不同研究者报道的方解石在25℃与90℃下的同位素分馏差值差异，以及因样品在不同温度（25℃与90℃）下反应所得到的温度与Δ47值之间的斜率差异。