Experimental Study of Water Leakage from Melt Inclusions in Quartz During Laboratory Heating

捕获在火成岩矿物中的玻璃状硅酸盐熔体包裹体含有活火山下方岩浆室中存在的熔体样本。这些包裹体为确定岩浆中的水浓度提供了最好的工具之一，并已被用于确定岩浆中存在的挥发物。此外，由于水在硅酸盐熔体中的溶解度作为P、T和X的函数是众所周知的，因此可以根据水的含量来估计捕集压力。利用熔融包裹体了解岩浆室中的过程所需的一个基本假设是，包裹体在捕获后没有失去或获得成分。虽然这一假设通常适用于大多数熔体成分，但众所周知，水(或氢)很容易通过大多数矿物扩散，并可能在捕获后从包裹体中损失(或获得)。该项目涉及使用天然和合成硅酸盐熔体包裹体进行系统研究，以确定最有可能保持熔体包裹体原始水分的实验室加热技术。天然和合成硅酸盐熔体包裹体将在加热前进行表征，以确定其大小、形状和与晶体表面或断裂的距离，然后通过几种技术之一进行加热，然后对熔体进行拉曼分析以确定水分含量。这些结果将被用来开发一种选择和均化结晶硅酸盐熔体包裹体的方案，从而将水分损失降至最低。该项目的广泛影响包括对研究生和本科生进行现代实验和分析技术方面的培训。该项目的一个重要外展部分涉及建立罗德数字图书馆。该资料库将包括罗德博士在其68年的职业生涯中发表的所有流体包裹体的数字图像。这些图像将通过万维网供教育和研究使用，并成为在广泛的地球科学领域进行教学和研究的重要资源。

Glassy, silicate melt inclusions trapped in igneous minerals contain samples of the melt that was present in the magma chamber beneath an active volcano. These inclusions provide one of the best tools available for determining water concentrations in magmas, and have been used to determine the volatiles present in magmas. Moreover, because the solubility of water in silicate melts as a function of P, T and X is well known, the pressure at trapping may be estimated from the water content. A basic assumption required to use melt inclusions to understand processes in magma chambers is that the inclusions have not lost or gained components following trapping. While this assumption is generally valid for most melt components, it is known that water (or hydrogen) diffuses through most minerals very easily and can be lost from (or gained by) inclusions following entrapment.This project involves a systematic study using both natural and synthetic silicate melt inclusions to identify those laboratory heating techniques that are most likely to preserve the original water content of the melt inclusions. Natural and synthetic silicate melt inclusions will be characterized before heating to determine the size, shape, and distance from the crystal surface or fracture, and then heated by one of several techniques, followed by Raman analysis of the melt to determine the water content. These results will be used to develop a protocol for selecting and homogenizing crystallized silicate melt inclusions that will minimize water loss.Broader impacts of this project include the training of both graduate and undergraduate students in modern experimental and analytical techniques. An important outreach component of this project involves the establishment of the Roedder Digital Library. The library will include digital images of all the fluid inclusions that Dr. Roedder has published over his 68-year professional career. These images will be made available for educational and research usage through the worldwide web and become an important resource for those teaching and conducting research in a broad range of earth science areas.