Nitrogen incorporation in silicates and metals: Results from SIMS, EPMA, FTIR, and laser-extraction mass spectrometry
Nitrogen incorporation in silicates and metals: Results from SIMS, EPMA, FTIR, and laser-extraction mass spectrometry
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硅酸盐和金属中的氮掺入：SIMS、EPMA、FTIR 和激光提取质谱的结果
DOI：
10.2138/am-2019-6533
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发表时间：
2019
影响因子：
3.1
通讯作者：
M. Hirschmann
中科院分区：
文献类型：
--
作者：
J. Mosenfelder;A. Handt;E. Füri;C. Dalou;R. Hervig;G. Rossman;M. Hirschmann
摘要 定量了解地球材料中的氮掺入对于限制行星体的挥发性演化非常重要。我们结合化学（SIMS、EPMA 和激光萃取质谱）和光谱 (FTIR) 观察来研究硅酸盐玻璃、金属合金和含氮硅酸盐矿物（透明质酸）中的氮含量和形态机制。通过所有四种方法研究了一套无铁玄武岩玻璃。通过 EPMA 测定的这些玻璃中的 N 浓度系统地高于通过激光提取测量的浓度，但在相互 2 秒的不确定性范围内一致，证明了 EPMA 方法的总体准确性。 SIMS 工作曲线基于 14N+ 和 14N16O- 的测量，作为由 EPMA（或激光提取）确定的 N 含量的函数，最适合指数函数，而不是最常应用于 SIMS 数据的线性回归。另一方面，对于贫碳、无铁玻璃，基于 12C14N- 的关系非常适合线性回归（r2 = 1，p < 0.001），这与之前对含氮量较低的玻璃的研究的预期形成鲜明对比。数据并不能证明与 Fe 或 H2O 含量相关的 SIMS 信号的基质效应是合理的，但含有 20 wt% BaO 的透明质的挥发性数据（N 和 H）揭示了可能由其高平均摩尔质量引起的基质效应。结合 FTIR 和化学数据，以及对文献的全面回顾，用于确定无铁玻璃中 N 的掺入机制。我们推断，在高压和高温的还原条件下，N 主要以 NH2−$\text{NH}_{2}^{-}$ 和 NH2– 的形式溶解在玄武岩熔体中，其中 N2 和/或氮化物 (X-N3–) 配合物 2 在低 fO2 条件下变得越来越重要，${{f}_{{{\text{O}}_{2}}}},$N 含量增加，H 含量减少。我们的结果对未来寻求通过 SIMS 精确测量 N 的研究以及与行星吸积和分化相关的高压下 N 分配的研究具有重要意义。
Abstract A quantitative understanding of nitrogen incorporation in Earth materials is important for constraining volatile evolution in planetary bodies. We used a combination of chemical (SIMS, EPMA, and laser-extraction mass spectrometry) and spectroscopic (FTIR) observations to study nitrogen contents and speciation mechanisms in silicate glasses, metal alloys, and an N-bearing silicate mineral (hyalophane). One suite of Fe-free basaltic glasses was studied by all four methods. Concentrations of N in these glasses determined by EPMA are systematically higher than those measured by laser extraction but agree within mutual 2s uncertainties, demonstrating the general veracity of the EPMA method. SIMS working curves based on measurement of 14N+ and 14N16O- as a function of N content determined by EPMA (or laser extraction) are best fit with exponential functions rather than the linear regressions that are most commonly applied to SIMS data. On the other hand, the relationship based on 12C14N- for C-poor, Fe-free glasses is exceptionally well fit to a linear regression (r2 = 1, p < 0.001), in contrast to expectations from previous work on glasses with lower N contents. Matrix effects on the SIMS signals associated with Fe or H2O content are not justified by the data, but volatile data (both N and H) for hyalophane, which contains 20 wt% BaO, reveal matrix effects possibly induced by its high average molar mass. A combination of FTIR and chemical data, together with a thorough review of the literature, was used to determine incorporation mechanisms for N in the Fe-free glasses. We infer that under reducing conditions at high pressure and temperature N is dissolved in basaltic melts chiefly as NH2−$\text{NH}_{2}^{-}$and NH2–, with N2 and/or nitride (X-N3–) complexes 2 becoming increasingly important at low fO2,${{f}_{{{\text{O}}_{2}}}},$increasing N content, and decreasing H content. Our results have implications for future studies seeking to accurately measure N by SIMS and for studies of N partitioning at high pressure relevant to planetary accretion and differentiation.
影响因子：
5.3
作者：
T. Yoshioka;M. Wiedenbeck;S. Shcheka;H. Keppler
通讯作者：
T. Yoshioka;M. Wiedenbeck;S. Shcheka;H. Keppler