Deformation-Induced Mechanical Instabilities at the Core-Mantle Boundary.

Petford, N., Rushmer, T. and Yuen, D.A., 2007. Deformation-Induced Mechanical Instabilities at the Core-Mantle Boundary. Geophysical monograph, 174, pp. 271-287.

Full text available as:

[img]
Preview
PDF
7MB

Official URL: http://cat.inist.fr/?aModele=afficheN&cpsidt=19974...

Abstract

Post-Perovskite: The Last Mantle Phase Transition 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 post-perovskite 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.

Item Type:Article
ISSN:0065-8448
Subjects:Science > Earth Sciences
Group:University Executive Team
ID Code:9246
Deposited By:INVALID USER
Deposited On:23 Jan 2009 17:58
Last Modified:07 Mar 2013 15:05

Document Downloads

More statistics for this item...
Repository Staff Only -
BU Staff Only -
Help Guide - Editing Your Items in BURO