Abstract
AT the base of the Earth's mantle is a region, called D″, which serves as a thermal and chemical boundary layer between the silicate mantle and the liquid-iron outer core1,2. Tomographic models of mantle compressional-wave velocity (vp) have their worst resolution in D″, owing to limited ray sampling3–5, but have hinted at large-scale lateral variations there. Here I use a new technique, which has its greatest resolution within D″, to produce a map of the large-scale vp variations within D″. The technique compares the arrival times of waves that have been refracted across and diffracted around the core–mantle boundary (CMB). The diffracted waves travel a long way in D″, making them excellent probes of this layer, and the differential technique removes many effects arising from ray paths outside of D″ (ref. 6). The new map provides an image of the continent-sized variations at the CMB that is complementary to existing shear-wave data7,8, and similarities between the map and projections of ancient subducted lithosphere9 verify previous suggestions10 of a strong coupling between surface plate tectonics and the base of the mantle.
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
Loper, D. E. & Lay, T. J. geophys. Res. 100, 6397–6420 (1995).
Lay, T. Eos 70, 49, 54–55, 58–59 (1989).
Inoue, H., Fukao, Y., Tanabe, K. & Ogata, Y. Phys. Earth planet. Inter. 59, 294–328 (1990).
Pulliam, R. J., Vasco, D. W. & Johnson, L. R. J. geophys. Res. 98, 699–734 (1993).
Vasco, D. W., Johnson, L. R., Pulliam, R. J. & Earle, P. S. J. geophys. Res. 99, 13727–13755 (1994).
Wysession, M. E., Valenzuela, R. W., Bartkó, L. & Zhu, A.-N. Phys. Earth planet. Inter. 92, 67–84 (1995).
Su, W., Woodward, R. L. & Dziewonski, A. M. J. geophys. Res. 99, 6945–6981 (1994).
Liu, X.-F., Su, W.-J. & Dziewonski, A. M. Eos (Spring mtg suppl.) 75 (16), 232 (1994).
Ricard, Y., Richards, M., Lithgow-Bertelloni, C. & Le Stunff, Y. J. geophys. Res. 98, 21895–21909 (1993).
Davies, G. F. J. geophys. Res. 89, 6017–6040 (1984).
Revenaugh, J. & Jordan, T. H. J. geophys. Res. 96, 19811–19824 (1991).
Houard, S. & Nataf, H.-C. Phys. Earth planet. Inter. 72, 264–275 (1992).
Vidale, J. E. & Benz, H. M. Nature 361, 529–532 (1993).
Kendall, J. M. & Shearer, P. M. J. geophys. Res. 99, 11575–11590 (1994).
Gamero, E. J. & Helmberger, D. V. Geophys. Res. Lett. 23, 977–980 (1996).
Maupin, V. Phys. Earth planet. Inter. 87, 1–32 (1994).
Kendall, J.-M. & Silver, P. G. Nature 381, 409–412 (1996).
Wysession, M. E., Okal, E. A. & Bina, C. R. J. geophys. Res. 97, 8749–8764 (1992).
Souriau, A. & Poupinet, G. Phys. Earth planet Inter. 84, 227–234 (1994).
Woodward, R. L. & Masters, G. Nature 352, 231–233 (1991).
Wysession, M. E., Bartkó, L. & Wilson, J. J. geophys. Res. 100, 8351 (1995).
Grand, S. P. J. geophys. Res. 99, 11591–11622 (1994).
Silver, P. G. & Bina, C. R. Geophys. Res. Lett. 20, 1135–1138 (1993).
Garnero, E. J. & Helmberger, D. V. J. geophys. Res. 98, 8225–8241 (1993).
Kennett, B. L. N. Seismic Wave Propagation in Stratified Media (Cambridge Univ. Press, Cambridge, 1983).
Dziewonski, A. M. & Anderson, D. L. Phys. Earth planet Inter. 25, 297–356 (1981).
Song, X. & Helmberger, D. V. Geophys. Res. Lett. 20, 2591–2594 (1993).
Menke, W. Geophysical Data Analysis: Discrete Inverse Theory 54–55 (Academic, San Diego, 1989).
Robertson, G. S. & Woodhouse, J. H. Eos (Fall mtg suppl.) 76 (46), 385 (1995).
Lay, T. A. Rev. Earth planet. Sci. 22, 33–61 (1994).
Van der Hilst, R. D. Nature 374, 154–157 (1995).
Dziewonski, A. M., Forte, A. M., Su, W.-J. & Woodward, R. L. in Relating Geophysical Structures and Processes: The Jeffreys Volume (eds Aki, K. & Dmowska, R.) 67–105 (Am. Geophys. Union, Washington DC, 1993).
Olson, P., Schubert, G. & Anderson, C. Nature 327, 409–413 (1987).
Zandt, G. & Ammon, C. J. Nature 374, 152–154 (1995).
Bloxham, J. & Jackson, A. Geophys. Res. Let. 17, 1997–2000 (1990).
Tackley, P. J., Stevenson, D. J., Glatzmaier, G. A. & Schubert, G. Nature 361, 699–704 (1993).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Wysession, M. Large-scale structure at the core–mantle boundary from diffracted waves. Nature 382, 244–248 (1996). https://doi.org/10.1038/382244a0
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1038/382244a0
This article is cited by
-
A tree of Indo-African mantle plumes imaged by seismic tomography
Nature Geoscience (2021)
-
Ultra-low velocity zone heterogeneities at the core–mantle boundary from diffracted PKKPab waves
Earth, Planets and Space (2017)
-
Strong, Multi-Scale Heterogeneity in Earth’s Lowermost Mantle
Scientific Reports (2015)
-
The influence of a chemical boundary layer on the fixity, spacing and lifetime of mantle plumes
Nature (2002)
-
The core–mantle boundary layer and deep Earth dynamics
Nature (1998)
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.
