Impedance spectra of hot, dry silicate minerals and rock; qualitative interpretation of spectra

Other| February 01, 1995 Impedance spectra of hot, dry silicate minerals and rock: Qualitative interpretation of spectra J. Stephen Huebner; J. Stephen Huebner U. S. Geological Survey, Reston, VA, United States Search for other works by this author on: GSW Google Scholar Roberta G. Dillenburg Roberta G. Dillenburg Search for other works by this author on: GSW Google Scholar Author and Article Information J. Stephen Huebner U. S. Geological Survey, Reston, VA, United States Roberta G. Dillenburg Publisher: Mineralogical Society of America First Online: 02 Mar 2017 Online ISSN: 1945-3027 Print ISSN: 0003-004X Copyright © 1995 by the Mineralogical Society of America American Mineralogist (1995) 80 (1-2): 46–64. https://doi.org/10.2138/am-1995-1-206 Article history First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation J. Stephen Huebner, Roberta G. Dillenburg; Impedance spectra of hot, dry silicate minerals and rock: Qualitative interpretation of spectra. American Mineralogist 1995;; 80 (1-2): 46–64. doi: https://doi.org/10.2138/am-1995-1-206 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyAmerican Mineralogist Search Advanced Search Abstract Impedance spectroscopy helps distinguish the contributions that grain interiors and grain boundaries make to electrical resistance of silicate minerals and rocks. The technique also distinguishes the low-frequency response due to the presence of instrument electrodes. We measured olivine, orthopyroxene, clinopyroxenes, and both natural and synthetic clinopyroxenite. Measurements were made at 1 bar, from 750 to 1150 °C, and over a frequency range from <10−4 to >106 Hz; some measurements were also made at 300–850 °C and 10–20 kbar. The grain-interior response lies at highest frequency, the sample-electrode response at low frequencies, and the grain boundary response at mid-frequencies. Grain interiors show as semicircular impedance arcs when plotted on the complex plane, and sample-electrode responses of hot single crystals and of hot dry rocks are exhibited as depressed arcs. In comparison, monofrequency measurements contain no information to identify the source of the response; at 1 kHz they detect only the resistance sum of grain interiors and grain boundaries and at low frequency (≤ 1 Hz) are likely to sense all three components. The major experimental problem is to find electrodes that make good contact with the sample and that are stable with time. The effect of pressure (10 kbar, 300–800 °C) is to diminish the resistance associated with grain boundaries and the sample-electrode interface, in the laboratory and presumably in nature. Monofrequency measurements at 1 bar may underestimate the conductivity of rocks at similar temperature but higher pressure.A network of electrical elements is presented for use in interpreting impedance spectra and conductive paths in hot or cold, wet or dry, minerals and rocks at any pressure. In dry rocks, a series network path predominates; in wet rocks, aqueous pore fluid and crystals both conduct. Finite resistance across the sample-electrode interface is evidence that electronic charge carriers are present at the surface, and presumably within, the silicate minerals and rocks measured. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.