Water in Subduction Zones

EAR-0309292 Peslier水对岩石圈中硅酸盐矿物、流体和熔体的化学和物理性质有很大影响。通过熔体向地壳输送或脱气从地幔释放出来的水，可能在俯冲带循环回到地幔。俯冲过程可能会将大量的水重新注入地幔。因此，在下降板脱水过程中发生的反应、板保存的水和排出到上覆地幔楔体的水的量、水是如何储存在这些不同的组分中以及以什么形式释放的，都是了解地幔水平衡的重要因素。该项目建议估计下部板块和上覆地幔楔体的水分含量，以阐明俯冲带的水输运平衡。这项研究集中在地幔、橄榄石、辉石和石榴石的原生相。这些名义上无水的矿物可能是在俯冲板块和板块上方的地幔中储存水(或者更确切地说，氢)的重要场所，在那里含水矿物可能不稳定。样本将在休斯顿大学准备进行分析。水的分析将在德克萨斯州休斯敦的NASA约翰逊航天中心进行傅里叶变换红外光谱(FTIR)。将使用位于德国拜罗伊特的巴伐利亚研究所的穆斯堡尔设备进行Fe3+/Fe比率测量，以计算氧逸度。该项目的第一个更广泛的影响是，Anne Peslier将能够在与当地和国际合作伙伴的协作环境中工作。该项目还将为休斯顿大学的实验室设施提供基础设施支持。最后，这笔赠款将帮助支持职业生涯早期的女性PI保持积极的研究，因此将有助于增加妇女在科学事业中的代表性。

EAR-0309292 PeslierWater has a strong influence on the chemical and physical properties of silicate minerals, fluids, and melts in the lithosphere. Water released from the mantle via melt transport to the crust, or degassing, may be recycled back into the mantle in subduction zones. Subduction processes likely add significant quantities of water back into the mantle. The reactions occurring during the dehydration of a down-going slab, the quantity of water being kept by the slab and that expelled to the overlying mantle wedge, how water is stored in these various components, and in what form it can be released, are therefore important factors in understanding the water budget of the mantle. This project proposes to estimate the water content of the down-going slab and that of the overlying mantle wedge, in order to shed light on the water transport budget at subduction zones. This study focuses on the primary phases of the mantle, olivine, pyroxene and garnet. These nominally anhydrous minerals may represent an important site for storing water (or more exactly hydrogen) in subducted slabs and in the mantle above slabs at depths where hydrous minerals may not be stable. The samples will be prepared for analysis at the University of Houston. The analyses of water will be performed by Fourier transform infrared spectrometry (FTIR) at NASA Johnson Space Center in Houston, Texas. Fe3+/Fe ratio measurements from which oxygen fugacities will be calculated will be performed with Mossbauer equipment at the Bavarian Research Institute at Bayreuth, Germany. The first broader impact of this project is that Anne Peslier will be able to work in a collaborative setting with local and international partners. This project will also provide infrastructure support for the laboratory facilities at the University of Houston. Finally this grant will help support an early-career female PI to maintain active research and as such will help increase the representation of women in the science enterprise.