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Laboratory measurements of the viscous anisotropy of olivine aggregates


A marked anisotropy in viscosity develops in Earth’s mantle as deformation strongly aligns the crystallographic axes of the individual grains that comprise the rocks. On the basis of geodynamic simulations, processes significantly affected by viscous anisotropy include post-glacial rebound1,2, foundering of lithosphere3 and melt production above subduction zones4. However, an estimate of the magnitude of viscous anisotropy based on the results of deformation experiments on single crystals5 differs by three orders of magnitude from that obtained by grain-scale numerical models of deforming aggregates with strong crystallographic alignment6,7,8. Complicating matters, recent experiments indicate that deformation of the uppermost mantle is dominated by dislocation-accommodated grain-boundary sliding9, a mechanism not activated in experiments on single crystals and not included in numerical models. Here, using direct measurements of the viscous anisotropy of highly deformed polycrystalline olivine, we demonstrate a significant directional dependence of viscosity. Specifically, shear viscosities measured in high-strain torsion experiments are 15 times smaller than normal viscosities measured in subsequent tension tests performed parallel to the torsion axis. This anisotropy is approximately an order of magnitude larger than that predicted by grain-scale simulations. These results indicate that dislocation-accommodated grain-boundary sliding produces an appreciable anisotropy in rock viscosity. We propose that crystallographic alignment imparts viscous anisotropy because the rate of deformation is limited by the movement of dislocations through the interiors of the crystallographically aligned grains. The maximum degree of anisotropy is reached at geologically low shear strain (of about ten) such that deforming regions of the upper mantle will exhibit significant viscous anisotropy.

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Figure 1: Overview of experiment design.
Figure 2: Mechanical and crystallographic data from entire data set.
Figure 3: Magnitude of viscous anisotropy, δ , as a function of strain and crystallographic-fabric strength.


  1. 1

    Christensen, U. R. Some geodynamical effects of anisotropic viscosity. Geophys. J. R. Astron. Soc. 91, 711–736 (1987)

    ADS  Article  Google Scholar 

  2. 2

    Han, D. & Wahr, J. An analysis of anisotropic mantle viscosity, and its possible effects on post-glacial rebound. Phys. Earth Planet. Inter. 102, 33–50 (1997)

    ADS  Article  Google Scholar 

  3. 3

    Lev, E. & Hager, B. H. Rayleigh-Taylor instabilities with anisotropic lithospheric viscosity. Geophys. J. Int. 173, 806–814 (2008)

    ADS  Article  Google Scholar 

  4. 4

    Lev, E. & Hager, B. H. Anisotropic viscosity changes subduction zone thermal structure. Geophys. Geochem. Geosyst. 12, Q04009 (2011)

    ADS  Article  Google Scholar 

  5. 5

    Durham, W. B. &. Goetze, C. Plastic flow of oriented single crystals of olivine 1. Mechanical data. J. Geophys. Res. 82, 5737–5753 (1977)

    ADS  CAS  Article  Google Scholar 

  6. 6

    Castelnau, O., Blackman, D. K., Lebensohn, R. & Castañeda, P. P. Micromechanical modeling of the viscoplastic behavior of olivine. J. Geophys. Res.. 113, B09202, (2008)

    ADS  Google Scholar 

  7. 7

    Knoll, M., Tommasi, A., Logé, R. E. & Signorelli, J. W. A multiscale approach to model the anisotropic deformation of lithospheric plates. Geochem. Geophys. Geosyst. 10, Q08009 (2009)

    ADS  Article  Google Scholar 

  8. 8

    Tommasi, A. et al. Structural reactivation in plate tectonics controlled by olivine crystal anisotropy. Nature Geosci. 2, 423–427 (2009)

    ADS  CAS  Article  Google Scholar 

  9. 9

    Hansen, L. N., Zimmerman, M. E. & Kohlstedt, D. L. The influence of microstructure on deformation of olivine in the grain-boundary sliding regime. J. Geophys. Res.. 117, B09201, (2012)

    ADS  Article  Google Scholar 

  10. 10

    Honda, S. Strong anisotropic flow in a finely layered asthenosphere. Geophys. Res. Lett. 13, 1454–1457 (1986)

    ADS  Article  Google Scholar 

  11. 11

    Vauchez, A., Tommasi, A. & Barruol, G. Rheological heterogeneity, mechanical anisotropy and deformation of the continental lithosphere. Tectonophysics 296, 61–86 (1998)

    ADS  Article  Google Scholar 

  12. 12

    Tommasi, A., Mainprice, D., Canova, G. & Chastel, Y. Viscoplastic self-consistent and equilibrium-based modeling of olivine lattice preferred orientations: implications for the upper mantle seismic anisotropy. J. Geophys. Res. 105, 7893–7908 (2000)

    ADS  CAS  Article  Google Scholar 

  13. 13

    Castelnau, O., Blackman, D. K. & Becker, T. W. Numerical simulations of texture development and associated rheological anisotropy in regions of complex mantle flow. Geophys. Res. Lett.. 36, L12304, (2009)

    ADS  Article  Google Scholar 

  14. 14

    Hansen, L. N., Zimmerman, M. E. & Kohlstedt, D. L. Grain-boundary sliding in San Carlos olivine: flow-law parameters and crystallographic-preferred orientation. J. Geophys. Res.. 116, B08201, (2011)

    ADS  Google Scholar 

  15. 15

    Zhang, S. & Karato, S. Lattice preferred orientation of olivine aggregates deformed in simple shear. Nature 375, 774–777 (1995)

    ADS  CAS  Article  Google Scholar 

  16. 16

    Bystricky, M., Kunze, K., Burlini, L. & Burg, J. P. High shear strain of olivine aggregates; rheological and seismic consequences. Science 290, 1564–1567 (2000)

    ADS  CAS  Article  Google Scholar 

  17. 17

    Paterson, M. S. & Olgaard, D. L. Rock deformation tests to large shear strains in torsion. J. Struct. Geol. 22, 1341–1358 (2000)

    ADS  Article  Google Scholar 

  18. 18

    Zhang, S., Karato, S., Fitzgerald, J., Faul, U. H. & Zhou, Y. Simple shear deformation of olivine aggregates. Tectonophysics 316, 133–152 (2000)

    ADS  CAS  Article  Google Scholar 

  19. 19

    Karato, S., Jung, H., Katayama, I. & Skemer, P. Geodynamic significance of seismic anisotropy of the upper mantle: new insights from laboratory studies. Annu. Rev. Earth Planet. Sci. 36, 59–95 (2008)

    ADS  CAS  Article  Google Scholar 

  20. 20

    Skemer, P., Katayama, I., Jiang, Z. & Karato, S. The misorientation index: development of a new method for calculating the strength of lattice-preferred orientation. Tectonophysics 411, 157–167 (2005)

    ADS  Article  Google Scholar 

  21. 21

    Launeau, P. & Cruden, A. R. Magmatic fabric acquisition mechanisms in a syenite; results of a combined anisotropy of magnetic susceptibility and image analysis study. J. Geophys. Res. 103, 5067–5089 (1998)

    ADS  CAS  Article  Google Scholar 

  22. 22

    Bricknell, R. H. & Edington, J. W. Mechanical anisotropy and deformation mechanisms in an Al-Cu-Zr superplastic alloy. Acta Metall. 27, 1313–1318 (1979)

    CAS  Article  Google Scholar 

  23. 23

    Barnett, M. R., Ghaderi, A., Sabirov, I. & Hutchinson, B. Role of grain boundary sliding in the anisotropy of magnesium alloys. Scr. Mater. 61, 277–280 (2009)

    CAS  Article  Google Scholar 

  24. 24

    Platt, J. P. & Behr, W. M. Grainsize evolution in ductile shear zones: implications for strain localization and the strength of the lithosphere. J. Struct. Geol. 33, 537–550 (2011)

    ADS  Article  Google Scholar 

  25. 25

    Podolefsky, N. S., Zhong, S. & McNamara, A. K. The anisotropic and rheological structure of the oceanic upper mantle from a simple model of plate shear. Geophys. J. Int. 158, 287–296 (2004)

    ADS  Article  Google Scholar 

  26. 26

    Behn, M. D., Hirth, G. & Elsenbeck, J. R. Implications of grain size evolution on the seismic structure of the oceanic upper mantle. Earth Planet. Sci. Lett. 282, 178–189 (2009)

    ADS  CAS  Article  Google Scholar 

  27. 27

    Cordier, P., Amodeo, J. & Carrez, P. Modelling the rheology of MgO under Earth’s mantle pressure, temperature and strain rates. Nature 481, 177–180 (2012)

    ADS  CAS  Article  Google Scholar 

  28. 28

    Becker, T. W. & Kawakatsu, H. On the role of anisotropic viscosity for plate-scale flow. Geophys. Res. Lett.. 38, L17307, (2011)

    ADS  Article  Google Scholar 

  29. 29

    Raterron, P., Girard, J. & Chen, J. Activities of olivine slip systems in the upper mantle. Phys. Earth Planet. Inter. 200–201, 105–112 (2012)

    ADS  Article  Google Scholar 

  30. 30

    Paterson, M. S. in The Brittle Ductile Transition in Rocks (eds Duba, A. G., Durham, W. B., Handin, J. W. & Wang, H. F. ) 187–194 (Geophys. Monogr. Ser. Vol. 56, American Geophysical Union, 1990)

    Book  Google Scholar 

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This work was supported by NSF grant EAR1214876. Parts of this work were carried out in the Institute of Technology Characterization Facility, University of Minnesota, which receives partial support from NSF through the NNIN programme. We thank T. Becker, B. Holtzman and A. Tommasi for discussions.

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All authors discussed experiment design. L.N.H. conducted sample preparation, deformation experiments, and microstructural and mechanical analyses. M.E.Z. aided in sample preparation and deformation experiments. L.N.H. wrote the initial draft of the manuscript. All authors discussed the results and commented on the manuscript.

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Correspondence to L. N. Hansen.

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The authors declare no competing financial interests.

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Hansen, L., Zimmerman, M. & Kohlstedt, D. Laboratory measurements of the viscous anisotropy of olivine aggregates. Nature 492, 415–418 (2012).

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