Impedance Spectroscopy and Grain Boundary Transport in Geological Materials

PI将检查晶粒尺寸、温度、氧逸度、体成分和熔体分数对晶界电响应的影响。特别重要的是将天然岩石与碾磨压实物进行比较，因为天然的晶界可能与实验室制备的材料的晶界大不相同。初始实验将在1巴的总压力下进行。随后的努力将把这项工作扩展到高温和高压的内部加热氩气压力容器和活塞气缸装置。这些结果将用与离子过程模型相关的等效电路来解释。这一研究结果对大地电磁资料的解释和建模具有重要意义，也将为研究不同地质环境下的晶界输运过程提供新的思路。

The PI will examine the influence of grain size, temperature, oxygen fugacity, bulk composition, and melt fraction on the grain boundary electrical response. Of particular importance will be the comparison of natural rocks with ground- and-pressed compacts because natural grain boundaries may be quite different than those in the laboratory-prepared materials. Initial experiments will be performed at 1-bar total pressure. Subsequent efforts will extend this work to elevated temperatures and pressures in internally-heated argon gas pressure vessels and piston cylinder devices. The results will be interpreted in terms of equivalent electrical circuits that can be related to models of ionic processes. This results of this study will be important for the interpretation and modeling of magnetotelluric data and will also shed new light on grain boundary transport processes in variety of geological environments.