Textural Constraints on Pumice Formation and the Development of Permeability in Silicic Magmas

挥发性析出和气体膨胀的过程强烈地影响火山的喷发方式。因此，岩浆泡化的速率和机制一直是火山学的一个基本问题。浮石碎屑囊泡性、囊泡结构、渗透性与喷发方式的关系将通过(1)浮石碎屑的详细结构测量来确定；(2)开发测定浮石在固体和液体状态下渗透率的技术；(3)通过使用基于显微镜的加热台和录像机对气泡聚结速率进行实验测量。这项工作将提供重要的新数据，为快速发展的岩浆上升、火山喷发柱沉降和岩浆破碎模型提供必要的输入。

9418008 Cashman Processes of volatile exsolution and gas expansion strongly influence eruptive styles of volcanoes. For this reason, rates and mechanisms of magmatic vesiculation have long been a fundamental question in volcanology. The relationship between pumice clast vesicularity, vesicle structure, permeability, and eruptive style will be determined by (1) making detailed structural measurements of pumice clasts; (2) developing techniques for determination of pumice permeability in both the solid and the liquid state, and (3) making experimental measurements of rates of bubble coalescence through use of a microscope-based heating stage and video recorder. This work will provide critical new data that are necessary input to rapidly-developing models of magma ascent, fallout of tephra eruption columns and magmatic fragmentation.