Light Element Incorporation in Nominally Anhydrous Minerals

水不仅是生命所必需的，而且对火山喷发、岩浆融化和上升以及岩石变形等地质过程也是必不可少的。在地质界，水的主要储集层被困在地球深处的固体岩石中，在那里它与矿物化学结合。在这些矿物中，水既以H2O分子的形式存在，也以其前体的形式存在，即氢原子以氢氧化物的形式与氧原子结合。虽然浓度相对较低，通常不到百万分之几百，但这种岩石的体积很大。这些水中的很大一部分被结合到我们通常认为是无水的矿物中。这些名义上无水的矿物包括长石、石英、橄榄石、石榴石和辉石。几十年来，加州理工学院的实验室开发了第一代分析标准，用于使用各种分析工具来确定名义上无水矿物的“水”含量。这些标准在美国和国外得到了广泛的传播。这些标准最初是为红外光谱分析而开发的，但现在，另一种名为二次离子质谱仪的分析技术在较小的区域提供了类似或更好的灵敏度。这种新方法不是自我校准的，在一定程度上依赖于以前开发的红外光谱标准。在某些方面，考虑到新方法提供的改进的空间敏感性，第一代标准被证明不是最优的。这项拟议的研究将重新评估现有标准，并开发新的第二代标准，以优化新发现的分析能力。这项工作的一部分将涉及对长石的广泛表征，长石是少数几种仍需使用质谱学方法进行研究的主要成岩矿物之一。由于社区对从陆地和外星样品中测量长石中的氢特别感兴趣，这项工作尤其具有时代性。它还将研究矿物中的氟离子，目的是改进校准方案，同时系统地研究从地幔提取的样品，这些样品表明氢和氟之间存在耦合。这些研究对于水等重要挥发性成分在地球上的位置以及它们如何影响岩石和矿物的性质这一根本问题至关重要。它们解决了哪些相含有微量‘水’以及浓度是多少的问题。它们还有助于了解这些挥发物在整个地球上的空间分布。分析标准也被用来解决太阳系其他地方(如月球)是否存在关键挥发物的问题。在具有技术重要性的名义上无水的合成矿物和相关的合成固体中是否存在少量的“水”，对高功率电子电路的支架、用于数据通信和光纤的电光晶体以及用于计算机、手表和电信设备的计时电路等设备的运行成功起着重要作用。这项研究将扩大社区对微量氢和氟在这些矿物和材料中发挥的重要作用的了解，并将通过为这些元素制定新的标准和评估校准协议而使国际社会受益。这项工作还为培养成为专业科学家和工程师的学生提供了直接参与研究过程的机会。

Water is essential not only to life, but also to geological processes such as volcanic eruption, magma melting and rising, and rock deformation. In the geological world, a major reservoir of water is tied up in solid rock deep in the Earth where it is chemically bound to the minerals. In these minerals, water is present both as the H2O molecule, and also as its precursor, the hydrogen atom bound to oxygen atoms in the form of hydroxide groups. Although the concentrations are relatively low, usually less than a few hundred parts per million, the volume of this rock is great. A large proportion of this water is incorporated into minerals we normally think of as anhydrous. These nominally anhydrous minerals include feldspars, quartz, olivine, garnets, and pyroxenes. For a couple decades, the Caltech lab has developed the first generation of analytical standards for determining the 'water' content of nominally anhydrous minerals using a variety of analytical tools. These standards have seen wide distribution across the United States and abroad. The standards were originally developed for use with infrared spectroscopy, but now, another analytical technique known as secondary ion mass spectrometry offers comparable or better sensitivity on smaller areas. The new method is not self-calibrating and has relied, in part, on the standards previously developed for infrared spectroscopy. In some ways, the first generation of standards is proving less than optimal in view of the improved spatial sensitivity offered by the new methods. The proposed study will re-evaluate existing standards and develop new, second generation ones to optimize the new-found analytical capabilities. Part of this work will involve an extensive characterization of feldspars, one of the few major rock-forming minerals that still need to be investigated using the mass spectrometry methods. This effort is particularly topical due to interest from the community in measuring H in feldspars from both terrestrial and extraterrestrial samples. It will also study fluorine ion incorporation in minerals with the goal of improving calibration protocols while systematically studying samples derived from the Earth's mantle were indications of a coupling between hydrogen and fluorine have been previously suggested. These studies are critical to the ultimate fundamental question of where the important volatile components such as water reside in the earth and how they influence the properties of rocks and minerals. They address the questions of which phases contain trace 'water' and at what concentrations. They also contribute to understanding the spatial distribution of these volatiles throughout our planet. The analytical standards are also used to address questions about the existence of critical volatiles elsewhere in the solar system such as the moon. The presence or absence of small amounts of 'water' in nominally anhydrous synthetic minerals and related synthetic solids of technological importance plays an important role in operational success of devices such as supports for high power electronic circuits, electro-optic crystals used in data communication and fiber optics, and timing circuits used in computers, watches and telecommunication devices. This research will broaden the communities understanding of the important role that trace amounts of hydrogen and fluorine play in such minerals and materials, and will benefit the international community through the development of new standards and assessment of calibration protocols for these elements. This work also provides opportunities for direct participation in the research process by students training to be professional scientists and engineers.