An assessment of iron isotope fractionation during core formation
An assessment of iron isotope fractionation during core formation
复制标题
岩心形成过程中铁同位素分馏的评估
DOI：
10.1016/j.chemgeo.2020.119800
复制
发表时间：
2020
期刊：
影响因子：
3.9
通讯作者：
E. Young
中科院分区：
文献类型：
--
作者：
A. Shahar;E. Young
铁在地球和地外环境中是一种普遍存在的元素，可以为行星尺度过程发生的条件提供线索。这方面的一个例子是确定在岩石行星和行星体中伴随金属核形成的条件。至少二十年来，有一个不断增长的实验和自然数据数据库，旨在了解铁同位素在硅酸盐和金属分离过程中是否发生分馏。虽然有人争辩说，这些数据彼此并不一致，但很明显，一旦建立了证明样品平衡的标准，当作为金属成分的函数来看待时，不同的研究之间有很好的一致性。在这些类型的实验中，证明平衡性是至关重要的。建立平衡的三同位素实验技术在数学上和基本上都是可靠的。此外，很明显，金属和硅酸盐之间是否存在平衡的铁同位素分馏的问题并不简单，它可能会随着温度、压力、金属成分、氧逸度和硅酸盐成分的变化而显著变化。
Iron is a ubiquitous element in terrestrial and extra-terrestrial settings and can provide clues as to the conditions during which planetary scale processes occurred. One example of this is determining the conditions accompanying metal core formation in rocky planets and planetesimals. For at least two decades there has been a growing database of experimental and natural data aimed at understanding whether iron isotopes fractionate during the separation of silicate and metal. While it has been argued that the data are not in agreement with one another, it is apparent that once criteria are established that prove equilibrated samples, there is good agreement amongst the different studies when looked at as a function of the metallic composition. Proving equilibrium is critical in these types of experiments. The three-isotope experimental technique for establishing equilibrium is found to be both mathematically and fundamentally sound. Further it is clear that the question of whether there is an equilibrium iron isotope fractionation between metal and silicate is not straightforward and that it can vary significantly as a function of temperature, pressure, metallic composition, oxygen fugacity, and silicate composition.