Electrical Properties of Rocks
I have been interested in the electrical properties of rocks since my PhD with Prof. Fred Vine at the University of East Anglia. Initial work at UEA concentrated on measuring the electrical conductivity of saturated crustal rocks at lower crustal temperatures and pressures. Later work has examined the effect of triaxial deformation on the electrical properties of rocks and the formulation of theory to describe surface conduction and electrical conduction mixing models in porous rocks.
Electrical
conductivity of rocks at lower crustal conditions. The initial
work we were able to measure the electrical conductivity of major crustal
lithologies in a saturated condition. The maximum confining pressure was about
1 GPa, the maximum pore fluid pressure was about 0.2 GPa and the maximum temperature
1100 degrees Celsius. Newly developed techniques were required to make electrical
conductivity measurements under these conditions including metallic sleeving,
active guard-ring electrodes and niobium-cold isostatically pressed pure alumina
ceramic leadthroughs.
Two major outcomes of the research were:
The original 1 GPa nitrogen gas cell used at UEA.
The effect of triaxial deformation on the electrical properties of rocks. A move to University College London enabled me to build electrical conductivity measurement into their existing hydrostatic, uniaxial and triaxial deformation apparatuses. The measurement of the electrical properties of rocks during triaxial deformation until failure and beyond showed that
The apparent Hookean behaviour prior to failure in porous rocks is not due to true elastic behaviour. Rather it is due to the combined self-organised processes of micro-crack closure perpendicular to the major axis of compression and the formation of new micro-cracks parallel to the major axis of compression.[pdf] [pdf]
Servo-controlled
triaxial rock deformation and rock physics ensemble can operate at confining
pressures to 400 MPa and temperatures to 400ºC. It incorporates an independent
400 MPa pore fluid pressure intensifier/porosimeter/permeameter, and load
is applied through a 1500 kN servo-controlled actuator. Rock samples (40mm
in diameter by 100mm long) are enclosed in engineered polymer jackets with
12 transducer mounting points. This allows real-time monitoring of changes
in elastic wave velocities (both P and S), electrical conductivity and electrical
potential, and 3D location of acoustic emission events generated during crack
propagation.
Theoretical development of surface conduction. In 1993 I started work on the theoretical formulation of surface conductivity of rocks (ISCOM1). Up until then surface conduction had been described semi-quantatively by adding a term to Archie`s relationship. The initial ideas were very basic but were improved when the PhD student called André Revil realigned his PhD to work on the subject. His mathematical input produced a robust quantitative theory of surface conduction that was much more consistent with existing observations and theory [pdf], and which led to a series of further papers. The Revil and Glover theory remains the most complete general theory of surface conduction in porous rocks available.
Theoretical development of models of electrical conduction in rocks. Another aspect of theoretical development involves the use of Archie`s law. There are a large number of mixing laws for electrical conductivity in rocks (parallel, perpendicular, Waff, Hashin-Shtrikman bounds, brick layer models...) which have a quantitative basis but no flexibility in the sense that they contain no ability to take into account a phase that remains the same volume but becomes more (or less) connected. Archie`s law is not quantitative, but contains in its cementation exponent, the ability to represent different connectivities of the conducting phase. The disadvantage is that there is only one conducting phase possible - the other is assumed to be a perfect insulator.
We modified Archie`s law in such a way that its advantages remain, but the matrix could be conducting. [pdf] This Archie`s law for 2 conducting phases arose from our need to have a mixing law with a variable connectivity that was applicable to the deep crust, where the matrix was significantly conducting. This allowed us to model partial melting in the ancient sub-Pyrenean subduction slab. [pdf]
Work is on-going on the extension of this work to produce a general Archie`s law for any number of conductiung phases, and to reinterpret the cementation exponent as a differential parameter. [pdf]
Publications
Glover, P.W.J., F.J. Vine, R.G. Ross, & G. Turner, The measurement of electrical resistivity of rocks under simulated crustal conditions, In High Pressure Geosciences and Materials Synthesis, Ed. H. Vollstädt, Akademie Verlag, Berlin, 46 49, 1988.
Glover, P.W.J., Ross, R.G. & Jolly, H., The measurement of saturated rock electrical conductivity at lower crustal temperatures and high pressures, High Press. Res., 5, 705 707, 1990.
Glover, P.W.J., Vine, F.J. & Ross, R.G., Measurements of saturated basic and acidic rock electrical conductivities at lower crustal temperatures and high pressures, High Press. Res., 5, 735 737, 1990.
Glover, P.W.J., & Ross, R.G., A method of measuring the electric conductivity of saturated rocks in a high pressure cell subjected to high temperatures, High Temp. High Press., 22, 533 539, 1990.
Glover, P.W.J. & Vine, F.J., Electrical conductivity of carbon bearing granulite at raised temperatures and pressures, Nature, 360, 723 726, 1992. [pdf]
Glover, P.W.J. & Vine, F.J., Electrical conductivity of the continental crust, Geophys.Res.Lett., 21(22), 2357 2360, 1994.
Glover, P.W.J., Meredith, P.G., Sammonds, P.R. & Murrell, S.A.F., Ionic surface electrical conductivity in sandstone, J.Geophys.Res., 99(B11), 21635 21650, 1994.
Glover, P.W.J., P.G. Meredith, P.R. Sammonds, & S.A.F. Murrell, Measurements of complex electrical conductivity and fluid permeability in porous rocks at raised confining pressures, In Rock Mechanics in Petroleum Engineering, Proceedings of EUROCK '94, SPE/ISRM International Conference, Delft, The Netherlands, Balkema, Amsterdam, 29 36, 1994.
Glover, P.W.J. & Vine, F.J., Beyond KTB Electrical conductivity of the deep continental crust, Surveys in Geophysics, 16, 5 36, 1995.[pdf]
Glover, P.W.J., Baud, P., Darot, M. Meredith, P.G., LeRavalec, M., Zoussi, S., & Reuschlé, T., Alpha/beta phase transition in quartz monitored using acoustic emissions, Geophys.J.Int., 120, 775 782, 1995. [pdf]
Glover, P.W.J., Gomez, J.B., Meredith, P.G., Boon, S.A., Sammonds, P.R., & Murrell, S.A.F., Modelling the Stress/Strain Behaviour of Saturated Rocks Undergoing Triaxial Deformation using Complex Electrical Conductivity Measurements, In Integrated Experimental Measurements and Theoretical Modelling of Rock Transport Properties, ed. Glover, P.W.J., Surveys in Geophysics Spec. Vol., 17, 307-330, 1996. [pdf]
Glover, P.W.J., (Editor), Integrated Experimental Measurements and Theoretical Modelling of Rock Transport Properties, Surv. in Geophys., Spec. Vol., 17(3), Kluwer, Amsterdam, 1996.
Glover, P.W.J., Graphite and electrical conductivity in the lower continental crust: A review, Phys.Chem.Earth, 21(4), 279-287, 1996.[pdf]
Glover, P.W.J., J.B. Gomez, P.G. Meredith, K. Hayashi, P.R. Sammonds & S.A.F. Murrell, Damage of saturated rocks undergoing triaxial deformation using complex electrical conductivity measurements: Experimental results, Phys.Chem.Earth, 22(1-2), 57-61, 1997. [pdf]
Gomez, J.B., P.W.J. Glover & P.G. Meredith, Damage of saturated rocks undergoing triaxial deformation using complex electrical conductivity measurements: Mechanical modelling, Phys.Chem.Earth, 22(1-2), 63-68, 1997. [pdf]
Revil, A. & Glover, P.W.J., Theory of ionic surface electrical conduction in porous media, Phys.Rev.B, 55(3), 1757-1773, 1997. [pdf]
Revil, A. & Glover, P.W.J., Nature of surface electrical conductivity in natural sands, sandstones, and clays, Geophys.Res.Lett., 25(5), 691-694, 1998.
Revil, A., P. Pezard & P.W.J. Glover, Streaming potential in porous media. I. Theory of the zeta-potential, J. Geophys. Res., 104(B9), 20021-20031, 1999.
Glover, P.W.J., Gómez, J.B. & Meredith, P.G., Fracturing in saturated rocks undergoing triaxial deformation using complex electrical conductivity measurements: Experimental study, Earth Planet. Sci. Lett., 183(1-2), 201-213, 2000. [pdf]
Glover, P.W.J., Pous, J., Queralt, P., Muñoz, J.-A., Liesa, M. & Hole, M.J., Integrated two dimensional lithospheric conductivity modelling in the Pyrenees using field-scale and laboratory measurements, Earth Planet. Sci. Lett., 178(1-2), 59-72, 2000. [pdf]
Glover, P.W.J., Hole, M.J. & Pous, J., A modified Archie's Law for two conducting phases, Earth Planet. Sci. Lett., 180(3-4), 369-383, 2000. [pdf]
Einaudi, F., Pezard, P.A., Iledefonse, B. & Glover, P.W.J., Electrical properties of slow spreading ridge gabbros from ODP Hole 1105A, SW Indian Ridge, in Petrophysical Properties of Crystalline Rocks, eds., P.K. Harvey, T.S. Brewer, P.A. Pezard & V.A. Petrov, Geological Society Special Publication 240, 179-193, 2005.
Glover, P.W.J. & Adám, A., Correlation between crustal high conductivity zones and seismic activity and the role of carbon during shear deformation, 2008, J. Geophys. Res., 113, B12210, doi:10.1029/2008JB005804. [pdf]
Glover, P.W.J., A generalised Archie's law for n-phases, in preparation for Geophysics.
Gómez, J.B., Glover, P.W.J. & Meredith, P.G., Fracturing in saturated rocks undergoing triaxial deformation using complex electrical conductivity measurements: Damage models, in abeyance for J. Geophys. Res.
Glover, P.W.J., What is the cementation exponent? A new interpretation, 2009, The Leading Edge, January 2009, 82-85. [pdf]
Glover, P.W.J. & Walker, E., A grain size to effective pore size transformation derived from an electro-kinetic theory, Geophysics, 74(1), E17-E29, 2009. [pdf]
Presentations
Glover, P.W.J., F.J. Vine, R.G. Ross, & G. Turner, The measurement of electrical resistivity of rocks under simulated crustal conditions, 25th EHPRG International Conference on High Pressure Geosciences and Material Sciences, 25 27 August 1987, Potsdam, East Germany, 1987.
Glover, P.W.J., R.G. Ross, & H. Jolly, The measurement of saturated rock electrical conductivity at lower crustal temperatures and high pressures, 12th AIRAPT & 27th EHPRG International Conference on High Pressure Science and Technology, 17 21 July 1989, University of Paderborn, Germany, 1989.
Glover, P.W.J., F.J. Vine, & R.G. Ross, R.G., Measurements of saturated basic and acidic rock electrical conductivities at lower crustal temperatures and high pressures, 12th AIRAPT & 27th EHPRG International Conference on High Pressure Science and Technology, 17 21 July 1989, University of Paderborn, Germany, 1989.
Glover, P.W.J. & F.J. Vine, Electrical conductivity measurements made under hydrostatic pressure, High Pressure Technology Association one day discussion meeting on High Pressure Research in Earth Sciences, University College London, 5th July 1990, 1990.
Glover, P.W.J., P.G. Meredith & P.R. Sammonds, Complex electrical conductivity and fractal pore surfaces of rocks subjected to confining pressures, 18th General Assembly of the European Geophysical Society, 1993.
Glover, P.W.J., Electrical conductivity of graphite bearing lower crustal rocks at lower crustal temperatures and raised pressures, 18th General Assembly of the European Geophysical Society, 1993.
Glover, P.W.J., P.G. Meredith, P.R. Sammonds, & S.A.F. Murrell, Measurements of complex electrical conductivity and fluid permeability in porous rocks at raised confining pressures, EUROCK '94, SPE/ISRM International Conference on Rock Mechanics in Petroleum Engineering, Delft, The Netherlands, Balkema, Amsterdam, 29 36, 1994.
Glover, P.W.J., P.G. Meredith, P.R. Sammonds, & S.A.F. Murrell, A new theory of ionic adsorption on saturated mineral surfaces: Implications for ionic surface conduction in saturated rocks, 19th General Assembly of the European Geophysical Society, 1994.
Baud, P., P.W.J. Glover, M. Darot, M. LeRavalec, T. Reuschlé, S. Zoussi, & P.G. Meredith, Thermal cracking in quartz as a result of the Alpha/beta phase transition monitored using acoustic emissions, 19th General Assembly of the European Geophysical Society, 1994.
Glover, P.W.J., P.G. Meredith, P.R. Sammonds, S.A.F. Murrell, and S.A. Boon, Surface electrical conduction and the fractal nature of pore and crack surfaces in saturated rocks, International Symposium on Fractal Fracture Mechanics, solicited paper, 1st Nov., 1994, Tokyo, 1994.
Glover, P.W.J., P.G. Meredith, P.R. Sammonds, & S.A.F. Murrell, Complex electrical conductivity of saturated rocks undergoing triaxial deformation: Experimental data and mechanical modelling, 20th General Assembly of the European Geophysical Society, 1995.
Glover, P.W.J., P.G. Meredith, P.R. Sammonds, & S.A.F. Murrell, Complex electrical conductivity of saturated rocks undergoing triaxial deformation: Experimental data and mechanical modelling, XXII International Union of Geodesy and Geophysics, International Conference, Boulder Colorado, USA, 2-14 July 1995, 1995.
Glover, P.W.J., Graphite and electrical conductivity in the lower continental crust: A review, 13th IUGG Workshop on Electromagnetic Induction in the Earth, July 12-18 1996, Onuma, Hokkaido, Japan, 1996.
Glover, P.W.J., High Electrical Conductivity in the Earth`s Continental Crust, Symposium of the Assistant Professor`s Society of the University of Tohoku, University of Tohoku, Sendai, Japan, May 1996.
Glover, P.W.J., Graphite and electrical conductivity in the lower continental crust: A review, 21st General Assembly of the European Geophysical Society, 1996.
Glover, P.W.J., J.B. Gómez, P.G. Meredith, & K. Hayashi, Damage of saturated rocks undergoing triaxial deformation using complex electrical conductivity measurements: Experimental results, 21st General Assembly of the European Geophysical Society, 1996.
Gómez, J.B., P.W.J. Glover & P.G. Meredith, Damage of saturated rocks undergoing triaxial deformation using complex electrical conductivity measurements: Mechanical modelling, 21st General Assembly of the European Geophysical Society, 1996.
Glover, P.W.J., Causes of High Electrical Conductivity in the Continental Crust, Technical University of Berlin Seminar, Technical University of Berlin, Germany, May 1997.
Glover, P.W.J., Causes of High Electrical Conductivity in the Continental Crust, University of Göttingen Seminar, University of Göttingen, Germany, May 1997.
Glover, P.W.J., Causes of High Electrical Conductivity in the Continental Crust, Free University of Berlin Seminar, Free University of Berlin, Germany, May 1997.
Glover, P.W.J., Causes of High Electrical Conductivity in the Continental Crust, University of Frankfürt Seminar, University of Frankfürt , Germany, May 1997.
Glover, P.W.J., Electrical conductivity in the Earth`s crust; A review of data and mechanisms, Aberdeen Geological Society Seminar, April 1998.
Glover, P.W.J. & C. Taylor, A new triaxial rock deformation cell for real-time imaging of fracture development in rocks, 24th General Assembly of the European Geophysical Society, 1999.
Pous, J., P.W.J. Glover, J. Muñoz, P. Queralt, M. Liesa & M.J. Hole, Partial melt fraction determination in the Pyrenees using magnetotelluric and laboratory data, 24th General Assembly of the European Geophysical Society, 1999.
Glover, P.W.J., Hole, M. & Pous, J., A modified Archie's law for two conducting phases, 25th General Assembly of the European Geophysical Society Nice, France, 25-29th April, 2000. [pdf]
Glover, P.W.J., Pous, J., Muñoz, J., Queralt, P., Liesa, M. & Hole, M., Integrated lithospheric conductivity modelling in the Pyrenees using laboratory and field data, 25th General Assembly of the European Geophysical Society Nice, France, 25-29th April, 2000.[pdf]
Glover, P.W.J., The electrical properties of saturated crustal rocks: measurement and implications (présentation), ALIANCE/ISTEEM Seminar (solicited paper), University of Montpellier, Montpellier, France, 13th March, 2002. [pdf]
Glover, P.W.J., Déry, N. & Ransford, T.J., Modelling the complex electrical properties of porous media as a function of frequency, Accepted, Poster, EGU 2006, EGU06-A-10732, 2-7 April 2006. [pdf]
Glover, P.W.J., What is the cementation exponent? A new differential interpretation, Oral, EGU 2009, EGU2009-319, Vienna, 19-24 April 2009. [abstract] [presentation]
Glover, P.W.J., Ogilvie, S.R., Isakov, E., A new method for calculating the mean aperture of fractures in rocks: The dual mean, Poster, EGU 2009, EGU2009-325, Vienna, 19-24 April 2009. [abstract] [poster]
Glover, P.W.J., Measurements, modelling and applications of the electro-kinetic properties of rocks, Oral, Geodetic and Geophysical Research Institute, Hungarian Academy of Sciences, Sopron, Hungary, Invited Lecture as part of the GASTEM Lecture Tour 2009, 27 April 2009. [abstract] [presentation]
Glover, P.W.J., Measurements, modelling and applications of the electro-kinetic properties of rocks, Oral, University of Padua, Italy, Invited Lecture as part of the GASTEM Lecture Tour 2009, 29 April 2009. [abstract] [presentation]
Glover, P.W.J., Measurements, modelling and applications of the electro-kinetic properties of rocks, Oral, ETHZ, Zurich, Switzerland, Invited Lecture as part of the GASTEM Lecture Tour 2009, 12 or 13 May 2009. [abstract] [presentation]
Glover, P.W.J., Measurements, modelling and applications of the electro-kinetic properties of rocks, Oral, University of Strasbourg, France, Invited Lecture as part of the GASTEM Lecture Tour 2009, 11 May 2009. [abstract] [presentation]
Glover, P.W.J., Measurements, modelling and applications of the electro-kinetic properties of rocks, Oral, University of Paris II, France, Invited Lecture as part of the GASTEM Lecture Tour 2009, 19 May 2009. [abstract] [presentation]
Glover, P.W.J., Measurements, modelling and applications of the electro-kinetic properties of rocks, Oral, Imperial College of Science, Technology and Medicine, University of London, UK, Invited Lecture as part of the GASTEM Lecture Tour 2009, June/July 2009. [abstract] [presentation]
Glover, P.W.J., A differential interpretation of the cementation exponent, Oral, 2009 Joint Assembly, GA13, Toronto, 24-27 May 2009. [abstract] [presentation]
Glover, P.W.J. and Walker, E., How are grain size and pore size related? A transformation based on electro-kinetic theory, Poster, 2009 Joint Assembly, GA13, Toronto, 24-27 May 2009. [abstract] [poster]
© Copyright, Paul Glover 2008, 2009: Last updated 03/03/2009