Constraints on Mantle Fluids and Hydrous Phases from High Pressure Diamond Anvil Cell Experiments

该项目有一个研究计划，在高压和高温下使用光谱技术(特别是红外光谱)的组合来检查各种不纯水溶液的结构和形态。该小组的初步研究将重点放在压力接近10 Gpa、温度为600°C的含卤化物和碳酸盐的富水系统。这些条件与地球内部板岩-地幔界面有关的条件相一致，因此与俯冲洋壳和沉积物的脱水条件相一致。因此，这种流体代表了最终产生与弧形火山作用有关的水合熔融的流体。主要的科学目标是描述由于杂质和高压和温度的结果而在水本身内发生的结构变化-这些变化与高压下水溶液的化学行为的显著变化相关-并在可行的情况下表征杂质本身的局部成键环境。这些研究有望阐明俯冲过程中最鲜为人知的特征之一：流体的行为最终导致地球周围与俯冲相关的岩浆活动。

This project has a research plan to examine the structure and speciation of a variety of impure aqueous fluids using a combination of spectroscopic techniques (particularly infrared spectroscopy) at high pressures and temperatures. Initial studies by the team will focus on halide- and carbonate-bearing water-rich systems to pressures near 10 GPa and temperatures of 600°C. These conditions are compatible with those associated with the slab-mantle interface within the planet, and thus with the dehydration of subducted oceanic crust and sediments. Such fluids are thus representative of the fluids that ultimately generate the initiation of hydrous melting associated with arc volcanism. The main scientific goals are to characterize the structural changes taking place within the water itself as a consequence of both impurities and high pressures and temperatures - changes that have been associated with marked shifts in the chemical behavior of aqueous solutions at high pressures - and to, where feasible, characterize the local bonding environment of the impurity itself. These studies hold the prospect for illuminating one of the most poorly understand features of the subduction process: the behavior of the fluids that ultimately give rise to subduction-related magmatism around the planet.