Experimental determination of the xenon isotopic fractionation during adsorption
Experimental determination of the xenon isotopic fractionation during adsorption
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吸附过程中氙同位素分馏的实验测定
DOI：
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
B. Marty
中科院分区：
文献类型：
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作者：
Y. Marrocchi;B. Marty
稀有气体在固体中的吸附通常被用来解释它们在陨石、陆地岩石和行星大气中的丰度模式。由于这些元素在地球化学储层中呈现同位素变化，我们通过实验测试了中性稀有气体吸附可能导致同位素分馏的可能性。我们的实验包括吸附/解吸过程的循环，其中氙通过干酪根和蒙脱土上的平衡吸附逐渐从储层中损失。然后，任何同位素分馏都会通过类瑞利蒸馏实验得到放大。对于干酪根和蒙脱石，分馏因子 α 分别外推为-0.18‰±0.08‰/u 和-0.22‰±0.07‰/u（均在 2σ 水平）。因此，仅靠中性稀有气体的吸附不能解释陨石中捕获的稀有气体的特定同位素组成，也不能解释陆地和火星大气中氙的同位素组成。
Adsorption of noble gases into solids is often posited to account for their abundance patterns in meteorites, terrestrial rocks, and planetary atmospheres. Since these elements present isotope variations among geochemical reservoirs, we have experimentally tested the possibility that adsorption of neutral noble gases could result in isotopic fractionation. Our experiment consists of a cycle of adsorption/desorption processes in which xenon is progressively lost from a reservoir by equilibrium adsorption on kerogen and on montmorillonite. Any isotopic fractionation would then be amplified by the Rayleigh‐like distillation experiment. The fractionation factors α are extrapolated to be −0.18‰ ± 0.08‰ per u and −0.22‰ ± 0.07‰ per u (both at the 2σ level) for kerogen and montmorillonite, respectively. Thus, adsorption of neutral noble gases alone cannot account for the specific isotopic composition of noble gases trapped in meteorites, nor for the isotopic composition of xenon in the terrestrial and martian atmospheres.