Crustal rheology of the Himalaya and Southern Tibet inferred from magnetotelluric data


The Cenozoic collision between the Indian and Asian continents formed the Tibetan plateau, beginning about 70 million years ago. Since this time, at least 1,400 km of convergence has been accommodated1 by a combination of underthrusting of Indian2 and Asian lithosphere, crustal shortening3, horizontal extrusion4 and lithospheric delamination5. Rocks exposed in the Himalaya show evidence of crustal melting1,6 and are thought to have been exhumed by rapid erosion and climatically forced crustal flow7,8. Magnetotelluric data can be used to image subsurface electrical resistivity, a parameter sensitive to the presence of interconnected fluids in the host rock matrix, even at low volume fractions. Here we present magnetotelluric data from the Tibetan–Himalayan orogen from 77° E to 92° E, which show that low resistivity, interpreted as a partially molten layer, is present along at least 1,000 km of the southern margin of the Tibetan plateau. The inferred low viscosity of this layer is consistent with the development of climatically forced crustal flow in Southern Tibet.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Figure 1: Map of the Tibetan plateau showing the location of the MT profiles.
Figure 2: Resistivity models for the four profiles derived from inversions of the MT data.
Figure 3: Comparison of 100-line resistivity model and the INDEPTH common mid-point reflection profile. B1 and B2 are seismic bright spots that indicate zones with high fluid content.
Figure 4: Summary of laboratory measurements of the electrical resistivity and mechanical properties of a partially molten rock.


  1. 1

    Yin, A. & Harrison, T. M. Geologic evolution of the Himalayan-Tibetan orogen. Annu. Rev. Earth Planet. Sci. 28, 211–280 (2000)

  2. 2

    Argand, E. in Proceedings of the 13th International Geological Congress 170–372 (Brussels, 1924).

  3. 3

    Dewey, J. F. & Burke, K. A. Tibetan, Variscan and Precambrian Basement reactivation: products of continental collision. J. Geol. 81, 683 (1973)

  4. 4

    Tapponnier, P. et al. Oblique stepwise rise and growth of the Tibetan Plateau. Science 294, 1671–1677 (2001)

  5. 5

    Molnar, P., England, P. & Martinod, J. Mantle dynamics, uplift of the Tibetan Plateau and the Indian monsoon. Rev. Geophys. 31, 357–396 (1993)

  6. 6

    Le Fort, P. et al. Crustal generation of the Himalayan leucogranites. Tectonophysics 134, 39–57 (1987)

  7. 7

    Grujic, D., Hollister, L. S. & Parrish, R. R. Himalayan metamorphic sequence as an orogenic channel: insight from Bhutan. Earth Planet. Sci. Lett. 198, 177–191 (2002)

  8. 8

    Beaumont, C., Jamieson, R. A., Nguyen, M. H. & Lee, B. Himalayan tectonics explained by extrusion of a low-viscosity crustal channel coupled to focused surface denudation. Nature 414, 738–742 (2001)

  9. 9

    Lee, J. et al. Evolution of the Kangmar Dome, southern Tibet: Structural, petrologic, and thermochronologic constraints. Tectonics 19, 872–895 (2000)

  10. 10

    Owens, T. J. & Zandt, G. Implications of crustal property variations for models of Tibetan plateau evolution. Nature 387, 37–43 (1997)

  11. 11

    Nelson, K. D. et al. Partially molten middle crust beneath southern Tibet: synthesis of project INDEPTH results. Science 274, 1684–1687 (1996)

  12. 12

    Pham, V. N. et al. Partial melting zones in the crust in Southern Tibet from magnetotelluric results. Nature 319, 310–314 (1986)

  13. 13

    Francheteau, J. et al. High heat-flow in southern Tibet. Nature 307, 32–36 (1984)

  14. 14

    Wei, W. et al. Detection of widespread fluids in the Tibetan crust by magnetotelluric studies. Science 292, 716–718 (2001)

  15. 15

    Armijo, R., Tapponnier, P., Mercier, J. L. & Han, T. L. Quaternary extension in southern Tibet; field observations and tectonic implications. J. Geophys. Res. 91, 13803–13872 (1986)

  16. 16

    Jones, A. G., Chave, A. D., Auld, D., Bahr, K. & Egbert, G. A comparison of techniques for magnetotelluric response function estimation. J. Geophys. Res. 94, 14201–14213 (1989)

  17. 17

    Lemmonier, C. et al. Electrical structure of the Himalaya of Central Nepal: high conductivity around the mid-crustal ramp along the Main Himalayan Thrust. Geophys. Res. Lett. 26, 3261–3264 (1999)

  18. 18

    Gokarn, S. G., Gupta, G., Rao, C. K. & Selvaraj, C. Electrical structure across the Indus Tsangpo suture and Shyok suture zones in NW Himalaya using magnetotelluric studies. Geophys. Res. Lett. 29, 1–4 (2002)

  19. 19

    McNeice, G. M. & Jones, A. G. Multisite, multifrequency tensor decomposition of magnetotelluric data. Geophysics 66, 158–173 (2001)

  20. 20

    Rodi, W. & Mackie, R. L. Nonlinear conjugate gradients algorithm for 2-D magnetotelluric inversion. Geophysics 66, 174–187 (2001)

  21. 21

    Spratt, J., Jones, A. G., Nelson, K. D., Unsworth, M. J. & the INDEPTH MT team. Crustal structure of the India-Asia collision zone, southern Tibet, from INDEPTH MT investigations. Phys. Earth Planet. Inter. 150, 227–237 (2005)

  22. 22

    Makovsky, Y. & Klemperer, S. L. Measuring the seismic properties of Tibetan bright spots: Evidence for free aqueous fluids in the Tibetan middle crust. J. Geophys. Res. 104, 10795–10825 (1999)

  23. 23

    Li, S. et al. Partial melt or aqueous fluids in the Tibetan crust: constraints from INDEPTH magnetotelluric data. Geophys. J. Int. 153, 289–304 (2003)

  24. 24

    Gaillard, F., Scaillet, B. & Pichavant, M. Evidence for present-day leucogranite pluton growth in Tibet. Geology 32, 801–804 (2004)

  25. 25

    Schilling, F. R., Partzsch, G. M., Brasse, H. & Schwarz, G. Partial melting below the magmatic arc in the central Andes deduced from geoelectromagnetic field experiments and laboratory data. Phys. Earth Planet. Inter. 103, 17–31 (1997)

  26. 26

    Renner, J., Evans, B. & Hirth, G. On the rheologically critical melt fraction. Earth Planet. Sci. Lett. 181, 585–594 (2000)

  27. 27

    Rosenberg, C. & Handy, M. R. Experimental deformation of partially melted granite revisited: implications for the continental crust. J. Metamorph. Geol. 23, 19–28 (2005)

  28. 28

    Rutter, E. & Neumann, D. H. K. Experimental deformation of partially molten Westerly granite under fluid absent conditions with implications for the extraction of granitic magmas. J. Geophys. Res. 100, 15697–15715 (1995)

  29. 29

    Van der Molen, I. & Paterson, M. S. Experimental deformation of partially molten granite. Contrib. Mineral. Petrol. 70, 299–318 (1979)

  30. 30

    Clark, M. K. & Royden, L. H. Topographic ooze: Building the Eastern margin of Tibet by lower crustal flow. Geology 28, 703–706 (2000)

Download references


The MT data were collected and analysed with support from the US National Science Foundation, the Ministry of Land and Resources of China, the Ministry of Education of China, the National Science Foundation of China, NSERC (Canada) and the Alberta Ingenuity Fund. Data in India were collected with funding from the ESS Division, Department of Science and Technology, Government of India, under the Deep Continental Studies Program. Data acquisition in Nepal was supported by CNRS-INSU and by the French-Nepalese cooperation agreement. Discussions with M. Edwards, W. Kidd and D. Nelson are acknowledged. We dedicate this paper to the memory of Doug Nelson, who inspired us all.

Author information

Correspondence to M. J. Unsworth.

Ethics declarations

Competing interests

Reprints and permissions information is available at The authors declare no competing financial interests.

Supplementary information

Supplementary Figure 1

Detailed map of Southern Tibet showing the location of three INDEPTH MT profiles. Numbers refer to MT sites shown in Figure S2. ITS = Indus-Tsangpo suture. YGR = Yadong Gulu Rift. (PDF 5485 kb)

Supplementary Figure 2

This gives details of the fit of the MT data to the predicted fit of the models shown in Figure 2 of the main Letter. (PDF 252 kb)

Supplementary Figures Legends

This file contains captions for the two Supplementary Figures. (DOC 339 kb)

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Unsworth, M., Jones, A., Wei, W. et al. Crustal rheology of the Himalaya and Southern Tibet inferred from magnetotelluric data. Nature 438, 78–81 (2005) doi:10.1038/nature04154

Download citation

Further reading


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.