The nature of the 660-kilometer discontinuity in Earth's mantle from global seismic observations of PP precursors

Deuss, A. and Redfern, S. A. T. and Chambers, K. and Woodhouse, J. H. (2006) The nature of the 660-kilometer discontinuity in Earth's mantle from global seismic observations of PP precursors. Science, 311 (5758). pp. 198-201. DOI 10.1126/science.1120020

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Abstract

The 660-kilometer discontinuity, which separates Earth's upper and lower mantle, has been detected routinely on a global scale in underside reflections of precursors to SS shear waves. Here, we report observations of this discontinuity in many different regions, using precursors to compressional PP waves. The apparent absence of such precursors in previous studies had posed major problems for models of mantle composition. We find a complicated structure, showing single and double reflections ranging in depth from 640 to 720 kilometers, that requires the existence of multiple phase transitions at the base of the transition zone. The results are consistent with a pyrolite mantle composition.

Item Type: Article
Uncontrolled Keywords: 2006 AREP IA49 IA50 2006 P
Subjects: 02 - Geodynamics, Geophysics and Tectonics
03 - Mineral Sciences
Divisions: 02 - Geodynamics, Geophysics and Tectonics
Journal or Publication Title: Science
Volume: 311
Page Range: pp. 198-201
Identification Number: 10.1126/science.1120020
Depositing User: Sarah Humbert
Date Deposited: 16 Feb 2009 13:02
Last Modified: 23 Jul 2013 10:06
URI: http://eprints.esc.cam.ac.uk/id/eprint/242

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