High-temperature equilibrium isotope fractionation of non-traditional stable isotopes: Experiments, theory, and applications
High-temperature equilibrium isotope fractionation of non-traditional stable isotopes: Experiments, theory, and applications
复制标题
DOI：
10.1016/j.chemgeo.2014.12.013
复制
发表时间：
2013-12
期刊：
影响因子：
3.9
通讯作者：
E. Young;C. Manning;E. Schauble;A. Shahar;C. Macris;C. Lazar;M. Jordan
中科院分区：
文献类型：
--
作者：
E. Young;C. Manning;E. Schauble;A. Shahar;C. Macris;C. Lazar;M. Jordan
镁、硅、铁、镍等岩石形成元素的稳定同位素的高温分配是地球化学和宇宙化学研究的新工具。了解平衡矿物间分馏的基本驱动力来自基本的晶体化学，对于解释自然系统的数据是非常宝贵的。电荷和配位数都是影响键长和键刚度的关键因素，因此矿物相的相对倾向性也就影响了重同位素或轻同位素的富集。大量新数据的定量解释依赖于平衡分馏因子的细化，通过晶体化学推理，从头算预测，实验和分析表征良好的自然样品之间的反馈。这种多方面的方法导致在高温系统中使用非传统稳定同位素的发现速度很快。例如，随着矿物间Mg和Fe同位素比例分配偏离平衡，地幔中的开放系统传质变得越来越明显，块状硅酸盐地球和陨石之间同位素比例的差异正在定量地阐明地球核心形成的条件。这些应用主要依赖于精确的平衡分馏因子。
High-temperature partitioning of the stable isotopes of rock-forming elements like Mg, Si, Fe, Ni and others are useful new tools in geochemistry and cosmochemistry. Understanding the fundamental driving forces for equilibrium inter-mineral fractionation comes from basic crystal chemistry and is invaluable for interpreting data from natural systems. Both charge and coordination number are key factors affecting bond length and bond stiffness and therefore the relative proclivity of a mineral phase for concentrating heavy or light isotopes. Quantitative interpretation of the plethora of new data relies on refinements of equilibrium fractionation factors through a feedback between crystal chemical reasoning, ab initio predictions, experiments, and analyses of well-characterized natural samples. This multifaceted approach is leading to a rapid rate of discovery using non-traditional stable isotopes in high temperature systems. For example, open-system mass transfer in the mantle is becoming increasingly evident from departures from equilibrium Mg and Fe isotope ratio partitioning between minerals, and differences in isotope ratios between bulk silicate Earth and meteorites are elucidating the conditions for Earth's core formation quantitatively. These applications rely critically on accurate equilibrium fractionation factors.