Abstract
It is well known that water (as a source of hydrogen) affects the physical and chemical properties of minerals—for example, plastic deformation1,2,3 and melting temperature4—and accordingly plays an important role in the dynamics and geochemical evolution of the Earth. Estimating the water content of the Earth’s mantle by direct sampling provides only a limited data set from shallow regions (<200 km depth)5. Geophysical observations such as electrical conductivity are considered to be sensitive to water content6, but there has been no experimental study to determine the effect of water on the electrical conductivity of olivine, the most abundant mineral in the Earth’s mantle. Here we report a laboratory study of the dependence of the electrical conductivity of olivine aggregates on water content at high temperature and pressure. The electrical conductivity of synthetic polycrystalline olivine was determined from a.c. impedance measurements at a pressure of 4 GPa for a temperature range of 873–1,273 K for water contents of 0.01–0.08 wt%. The results show that the electrical conductivity is strongly dependent on water content but depends only modestly on temperature. The water content dependence of conductivity is best explained by a model in which electrical conduction is due to the motion of free protons. A comparison of the laboratory data with geophysical observations7,8,9,10 suggests that the typical oceanic asthenosphere contains ∼10-2 wt% water, whereas the water content in the continental upper mantle is less than ∼10-3 wt%.
This is a preview of subscription content, access via your institution
Access options
Subscribe to this journal
Receive 51 print issues and online access
$199.00 per year
only $3.90 per issue
Buy this article
- Purchase on Springer Link
- Instant access to full article PDF
Prices may be subject to local taxes which are calculated during checkout
Similar content being viewed by others
References
Karato, S. & Jung, H. Effects of pressure on high-temperature dislocation creep in olivine polycrystals. Phil. Mag. A 83, 401–414 (2003)
Karato, S., Paterson, M. S. & Fitz Gerald, J. D. Rheology of synthetic olivine aggregates: influence of grain-size and water. J. Geophys. Res. 91, 8151–8176 (1986)
Mei, S. & Kohlstedt, D. L. Influence of water on plastic deformation of olivine aggregates, 1. Diffusion creep regime. J. Geophys. Res. 105, 21457–21469 (2000)
Kushiro, I., Syono, Y. & Akimoto, S. Melting of a peridotite nodule at high pressures and high water pressures. J. Geophys. Res. 73, 6023–6029 (1968)
Bell, D. R. & Rossman, G. R. Water in Earth’s mantle: The role of nominally anhydrous minerals. Science 255, 1391–1397 (1992)
Karato, S. The role of hydrogen in the electrical conductivity of the upper mantle. Nature 347, 272–273 (1990)
Olsen, N. Long-period (30 days - 1 year) electromagnetic sounding and the electrical conductivity of the lower mantle beneath Europe. Geophys. J. Int. 138, 179–187 (1999)
Tarits, P., Hautot, S. & Perrier, F. Water in the mantle: Results from electrical conductivity beneath the French Alps. Geophys. Res. Lett. 31 doi: 10.1029/2003GL019277 (2004)
Evans, R. L. et al. Geophysical evidence from the MELT area for compositional control on oceanic plates. Nature 437, 249–252 (2005)
Lizarrale, D., Chave, A., Hirth, G. & Schultz, A. Northeastern Pacific mantle conductivity profile from long-period magnetotelluric sounding using Hawaii-to-California cable data. J. Geophys. Res. 100, 17837–17854 (1995)
Baba, K., Chave, A. D., Evans, R. L., Hirth, G. & Randall, L. Mantle dynamics beneath the East Pacific Rise at 17°S: Insights from the Mantle Electromagnetic and Tomography (MELT) experiments. J. Geophys. Res. 111 doi: 10.1029/2004JB003598 (2006)
Simpson, F. & Tommasi, A. Hydrogen diffusivity and electrical anisotropy of a peridotite mantle. Geophys. J. Int. 160, 1092–1102 (2005)
Hirth, G., Evans, R. L. & Chave, A. D. Comparison of continental and oceanic mantle electrical conductivity: Is Archean lithosphere dry?. Geochem. Geophys. Geosyst. 1 doi: 10.1029/2000GC000048 (2000)
Huang, X., Xu, Y. & Karato, S. Water content of the mantle transition zone from the electrical conductivity of wadsleyite and ringwoodite. Nature 434, 746–749 (2005)
Paterson, M. S. The determination of hydroxyl by infrared absorption in quartz, silicate glass and similar materials. Bull. Mineral. 105, 20–29 (1982)
Xu, Y., Poe, B. T., Shankland, T. J. & Rubie, D. C. Electrical conductivity of olivine, wadsleyite, and ringwoodite under upper-mantle conditions. Science 280, 1415–1418 (1998)
Wang, D. Studies on Electrical Properties of Minerals and Rocks Under Defined Thermodynamic Conditions. Ph.D. thesis, Chinese Acad. Sci. (2004)
Karato, S. Lattice Defects and Transport Properties of Olivine. M.Sc. thesis, Univ. Tokyo. (1974)
Schock, R. N., Duba, A. G. & Shankland, T. J. Electrical conduction in olivine. J. Geophys. Res. 94, 5829–5839 (1989)
Constable, S., Shankland, T. G. & Duba, A. The electrical conductivity of an isotropic olivine mantle. J. Geophys. Res. 97, 3397–3404 (1992)
Xu, Y., Shankland, T. J. & Duba, A. G. Pressure effect on electrical conductivity of mantle olivine. Phys. Earth Planet. Inter. 118, 149–161 (2000)
Kohlstedt, D. L. & Mackwell, S. J. Diffusion of hydrogen and intrinsic point defects in olivine. Z. Phys. Chem. 207, 147–162 (1998)
Hashin, Z. & Shtrikman, S. A variational approach to the theory of effective magnetic permeability of multiphase materials. J. Appl. Phys. 33, 3125–3131 (1962)
Hier-Majumder, S., Anderson, I. M. & Kohlstedt, D. L. Influence of protons on Fe-Mg interdiffusion in olivine. J. Geophys. Res. 110 doi: 10.1029/2004JB003292 (2005)
Bolfan-Casanova, N. Water in the Earth’s mantle. Mineral. Mag. 69, 229–257 (2005)
Simpson, F. Intensity and direction of lattice-preferred orientation of olivine: are electrical and seismic anisotropies of the Australian mantle reconcilable?. Earth Planet. Sci. Lett. 203, 535–547 (2002)
Gatzemeier, A. & Moorkamp, M. 3D modelling of electrical anisotropy from electromagnetic array data: hypothesis testing for different upper mantle conduction mechanisms. Phys. Earth Planet. Inter. 149, 225–242 (2005)
Stolper, E. M. Speciation of water in silicate melts. Geochim. Cosmochim. Acta 46, 2609–2620 (1982)
Kohlstedt, D. L., Keppler, H. & Rubie, D. C. Solubility of water in the α, β and γ phases of (Mg,Fe)2SiO4 . Contrib. Mineral. Petrol. 123, 345–357 (1996)
Ichiki, M. et al. Upper mantle conductivity structure of the back-arc region beneath northeastern China. Geophys. Res. Lett. 28, 3773–3776 (2001)
Acknowledgements
Z. Jing, Z. Jiang and I. Katayama provided the technical assistance that made this research possible. T. Kawazoe was most helpful with the error estimates. This work was supported by the NSF of China and the NSF of the United States. Author Contributions S.-i.K. supervised the whole project and completed the paper. The experimental measurements of conductivity and the data analysis were made largely by D.W. and M.M. in collaboration with Y.X.
Author information
Authors and Affiliations
Corresponding author
Ethics declarations
Competing interests
Reprints and permissions information is available at www.nature.com/reprints. The authors declare no competing financial interests.
Supplementary information
Supplementary Notes 1
A summary of experimental results. All experiments were conducted at 4 GPa. is water content, T is temperature and σ is electrical conductivity. (DOC 47 kb)
Supplementary Notes 2
A broad peak at ~3,400 cm-1 from the original spectrum is used to estimate the water content in the grains in each sample. (PDF 75 kb)
Rights and permissions
About this article
Cite this article
Wang, D., Mookherjee, M., Xu, Y. et al. The effect of water on the electrical conductivity of olivine. Nature 443, 977–980 (2006). https://doi.org/10.1038/nature05256
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1038/nature05256
Comments
By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.