Deformation-induced mechanical instabilities at the core-mantle boundary

Nick Petford, Tracy Rushmer, David A. Yuen

Research output: Chapter in Book/Report/Conference proceedingChapter

3 Citations (Scopus)

Abstract

Our understanding of the core-mantle boundary (CMB) region has improved significantly over the past several years due, in part, to the discovery of the postperovskite phase. Sesimic data suggest that the CMB region is highly heterogeneous, possibly reflecting chemical and physical interaction between outer core material and the lowermost mantle. In this contribution we present the results of a new mechanism of mass transfer across the CMB and comment on possible repercussions that include the initiation of deep, siderophile-enriched mantle plumes. We view the nature of core-mantle interaction, and the geodynamic and geochemical ramifications, as multiscale processes, both spatially and temporally. Three lengthscales are defined. On the microscale (1-50 km), we describe the effect of loading and subsequent shearing of the CMB region and show how this may drive local flow of outer core fluid upwards into D". We propose that larger scale processes operating on a mesoscale (50-300 km) and macroscale regimes (> 300 km) are linked to the microscale, and suggest ways in which these processes may impact on global mantle dynamics.

Original languageEnglish
Title of host publicationPost-perovskite
Subtitle of host publicationthe last mantle phase transition
EditorsKei Hirose, John Brodholt, Thorne Lay, David Yuen
Place of PublicationWashington, D.C.
PublisherAmerican Geophysical Union
Pages271-287
Number of pages17
ISBN (Electronic)9781118666401
ISBN (Print)9780875904399
DOIs
Publication statusPublished - 19 Mar 2007

Publication series

NameGeophysical Monograph Series
Volume174
ISSN (Print)0065-8448
ISSN (Electronic)2328-8779

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  • Cite this

    Petford, N., Rushmer, T., & Yuen, D. A. (2007). Deformation-induced mechanical instabilities at the core-mantle boundary. In K. Hirose, J. Brodholt, T. Lay, & D. Yuen (Eds.), Post-perovskite: the last mantle phase transition (pp. 271-287). (Geophysical Monograph Series; Vol. 174). Washington, D.C.: American Geophysical Union. https://doi.org/10.1029/174GM18