Defining the Role of Mixed H2O-CO2 Fluids in the Petrogenesis of Subduction-related Lavas

这项研究将集中在混合挥发分(H2O和CO2)对原始弧型岩浆演化的影响。由于最近的证据表明，在弧岩浆中存在大量的CO2，并且这些组分的热力学行为似乎是非Henrian的，因此将对两种不同(但相关的)熔体成分进行高压和温度实验，以1)确定混合H2O-CO2流体在熔体相中的溶解度关系，以及2)确定混合流体成分对亚液相线相平衡的影响。一旦确定，这些参数将把对弧形火山岩捕获的熔体包裹体中挥发性和主要元素浓度的直接测量置于熔体生成、迁移和地幔楔形体内分离的背景下，极大地提高我们解开引起俯冲相关火山作用的岩石成因过程的能力。这个项目将是实验室密集型的，吸引本科生使用高压/高温实验仪器和随后的实验运行产品的分析。

This research will focus on the effect of mixed volatiles (H2O and CO2) on the evolution of primitive arc-related magmas. As recent evidence has shown the presence of significant amounts of CO2 in arc magmas, and that the thermodynamic behavior of these components appears to be non-Henrian, high pressure and temperature experiments will be conducted on two different (but related) melt compositions in order to 1) determine the solubility relations of mixed H2O-CO2 fluids in the melt phase, and 2) determine the effect of mixed fluid composition on the sub-liquidus phase equilibria. Once determined, these parameters will place the direct measurements of volatile and major-element concentrations in trapped melt inclusions from arc volcanics in a context of melt generation, migration, and segregation in the mantle wedge, greatly increasing our ability to unravel petrogenetic processes giving rise to subduction-related volcanism. This project will be laboratory intensive, engaging undergraduate students in the use of high pressure/temperature experimental apparatus and the subsequent analysis of experimental run products.