Acquisition of Electrical Impedance Analyzer for the ASU Geological Sciences Mineral and Rock Physics Laboratory

Arizona State University, Scottsdale AZ

Investigators

Abstract

0092412 Tyburczy This grant provides partial support for the costs of acquiring an electrochemical impedance analysis system for the Mineral and Rock Physics Laboratory at Arizona State University (ASU). The PI is Professor of Geology at Arizona State University and will utilize this equipment for studies of the electrical properties of earth materials. Magnetotellurics and geomagnetic depth sounding have revealed zones of anomalously high electrical conductivity in a variety of crustal and mantle environments. In order to properly invert and interpret magnetotelluric response functions, the electrical response of Earth materials over a suitable frequency range must be determined in the laboratory. The equipment purchased will consist of an impedance analysis system consisting of a frequency response analyzer (FRA), a potentiostat, a personal computer and specialized software for data acquisition/control and data analysis/modeling. The equipment will be interfaced with a high temperature gas mixing furnace, with a multiple anvil high pressure device, and with other types of furnaces and pressure vessels. Studies to be pursued with this equipment include 1) the influence of melt composition and texture at low melt fraction on the bulk electrical properties of partially molten systems 2) effects of combined pressure and temperature on electrical properties of anhydrous minerals and rocks of the crust and mantle, and 3) the influence of hydrogen in hydrous and nominally anhydrous minerals on electrical properties. The results will be interpreted in terms of equivalent electrical circuits that can be related to models of ionic processes. The results of these studies will be important for the interpretation and modeling of magnetotelluric data and will also shed new light on physical transport processes in a variety of geological environments. The ultimate benefits will be more detailed understanding of the temperature profile and physical state of matter at depth in the Earth's interior. ***