Experimental Quantification of the Solubility of SiO2 and H2O in Clinopyroxene Versus Pressure

俯冲的大洋中脊玄武岩以榴辉岩的形式存在于地球的地幔中，这种岩石主要由石榴石和单斜辉石组成。虽然这两种矿物名义上都是无水的，但在许多因火山或构造作用而带到地球表面的榴辉岩中，已经发现了少量的水或氢氧化物。水对矿物的物理性质有很大影响。深入了解它的发生机制，将有助于我们更好地理解水在地幔中的输运，并有助于揭示地幔对流的动力学和陆壳的“循环”。本项目将通过一个专注于过量二氧化硅和羟基含量的实验计划来量化水取代的机理，特别是在4-12 Gpa的压力和900-1200oC的温度下，研究它们与单斜辉石中阳离子空位浓度的相关性。这项工作将扩展和完善以前对榴辉岩的温压解释，并确定水溶解度的上限。这项工作的更广泛影响包括对研究生和本科生进行高级分析技术教育。

Subducted mid-oceanic ridge basalt exists in the Earth's mantle as eclogite, a rock consisting mostly of the minerals garnet and clinopyroxene. Although both of these minerals are nominally anhydrous, a small amount of water or hydroxide has been identified in many eclogites brought to the Earth's surface by volcanic or tectonic processes. Water has major effects on the physical properties of minerals. Insight into the mechanisms of its occurrence will improve our understanding of the transport of water in the Earth's mantle, and cast light on the kinetics of mantle convection and the 'recycling' of the continental crust. This project will quantify the mechanisms for water substitution through an experimental program focused on excess SiO2 and OH contents, especially studying their correlation with cation vacancy concentrations in clinopyroxene at pressures of 4-12 GPa and temperatures of 900-1200oC. This work will extend and refine previous thermobarometric interpretations of eclogites and determine the upper limit of water solubility. The broader impacts of this work include education of graduate and undergraduate students in advanced analytical techniques.