Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.

Science 1 August 1997:
Vol. 277. no. 5326, pp. 670 - 673
DOI: 10.1126/science.277.5326.670
Prev | Table of Contents | Next

Reports

Seismic Evidence of Partial Melt Within a Possibly Ubiquitous Low-Velocity Layer at the Base of the Mantle

J. Revenaugh, * R. Meyer

Three source regions show evidence of a low-velocity layer that is less than 15 kilometers thick on top of the core-mantle boundary and require about a 3:1 ratio of shear-to-compressional velocity reduction, which is consistent with partial melt. Layer thickness is correlated with travel time residuals of the seismic phases that are most sensitive to the lowermost mantle velocity. These observations suggest that the layer is thinned beneath downwellings but is present everywhere along the core-mantle boundary. Low viscosity accompanying partial melt can localize the upwelling of warmed mantle, making the low-velocity layer a plausible source of mantle plumes.

J. Revenaugh, Institute of Tectonics, University of California, Santa Cruz, CA 95064, USA.
R. Meyer, Department of Geological Sciences, University of California, Santa Barbara, CA 93106, USA.
*   To whom correspondence should be addressed.

Read the Full Text


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Electronic and magnetic structures of the postperovskite-type Fe2O3 and implications for planetary magnetic records and deep interiors.
S.-H. Shim, A. Bengtson, D. Morgan, W. Sturhahn, K. Catalli, J. Zhao, M. Lerche, and V. Prakapenka (2009)
PNAS 106, 5508-5512
   Abstract »    Full Text »    PDF »
Implications of lower-mantle structural heterogeneity for the existence and nature of whole-mantle plumes.
E. J. Garnero, T. Lay, and A. McNamara (2007)
Geological Society of America Special Papers 430, 79-101
   Abstract »    Full Text »    PDF »
Seismic Detection of Rigid Zones at the Top of the Core.
S. Rost and J. Revenaugh (2001)
Science 294, 1911-1914
   Abstract »    Full Text »    PDF »
Sediments at the Top of Earth's Core.
B. A. Buffett, E. J. Garnero, and R. Jeanloz (2000)
Science 290, 1338-1342
   Abstract »    Full Text »
A Correlation Between Ultra-Low Basal Velocities in the Mantle and Hot Spots.
Q. Williams, J. Revenaugh, and E. Garnero (1998)
Science 281, 546-549
   Abstract »    Full Text »


To Advertise     Find Products

Science. ISSN 0036-8075 (print), 1095-9203 (online)