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 2 May 2008:
Vol. 320. no. 5876, pp. 626 - 628
DOI: 10.1126/science.1148028
Prev | Table of Contents | Next

Review

Structure and Dynamics of Earth's Lower Mantle

Edward J. Garnero* and Allen K. McNamara

Processes within the lowest several hundred kilometers of Earth's rocky mantle play a critical role in the evolution of the planet. Understanding Earth's lower mantle requires putting recent seismic and mineral physics discoveries into a self-consistent, geodynamically feasible context. Two nearly antipodal large low-shear-velocity provinces in the deep mantle likely represent chemically distinct and denser material. High-resolution seismological studies have revealed laterally varying seismic velocity discontinuities in the deepest few hundred kilometers, consistent with a phase transition from perovskite to post-perovskite. In the deepest tens of kilometers of the mantle, isolated pockets of ultralow seismic velocities may denote Earth's deepest magma chamber.

School of Earth and Space Exploration, Arizona State University, Box 871404, Tempe, AZ 85287, USA.

* To whom correspondence should be addressed. E-mail: garnero{at}asu.edu

Read the Full Text


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Shear viscosity and diffusion in liquid MgSiO3: Transport properties and implications for terrestrial planet magma oceans.
D. Nevins, F. J. Spera, and M. S. Ghiorso (2009)
American Mineralogist 94, 975-980
   Abstract »    Full Text »    PDF »
Tails of two plume types in one mantle.
A. Lenardic and A.M. Jellinek (2009)
Geology 37, 127-130
   Abstract »    Full Text »    PDF »


To Advertise     Find Products

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