Characterization of Al-Si ordering state in an alkali feldspar using atom location by channeling-enhanced microanalysis (ALCHEMI)
Characterization of Al-Si ordering state in an alkali feldspar using atom location by channeling-enhanced microanalysis (ALCHEMI)
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DOI：
10.2138/am.2010.3355
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发表时间：
2010
影响因子：
3.1
通讯作者：
Jun Wu;D. Veblen
中科院分区：
文献类型：
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作者：
Jun Wu;D. Veblen
摘要 采用沟道增强微量分析（ALCHEMI）原子定位技术确定了碱长石 T1o 位点（t1o）中 Al 原子的占据情况。基于先前研究证明的方法，分析电子显微镜被证明是一种充分表征长石骨架中 Al-Si 有序状态的可行技术。我们将此方法应用于来自马达加斯加 Itrongay 的正长石及其加热对应物。我们的初步结果表明，原始正长石的 2t1 (=t1o + t1m) 和 t1o 分别为 0.74 和 0.37，而加热的正长石则分别为 0.54 和 0.28。已经进行了单晶 X 射线衍射实验，结果与我们的 ALCHEMI 测量结果一致。这种新方法有望帮助解决一些与排序路径相关的复杂问题，例如长石中的孪晶和斜长石中的域共生。
Abstract Atom location by channeling-enhanced microanalysis (ALCHEMI) was used to determine the occupancy of Al atoms in the T1o site (t1o) of alkali feldspar. Building on the method demonstrated by previous research, analytical electron microscopy proves to be a viable technique for fully characterizing the Al-Si ordering state in the feldspar framework. We applied this method to orthoclase from Itrongay, Madagascar, and to its heated counterpart. Our preliminary results give 0.74 and 0.37 as 2t1 (=t1o + t1m) and t1o, respectively, for the original orthoclase, vs. 0.54 and 0.28 for heated orthoclase. Single-crystal X-ray diffraction experiments have been performed, and the results agree with our ALCHEMI measurements. This new method promises to help resolve some complex issues relating ordering paths, for example, twinning in feldspars and domain intergrowth in plagioclase.