TY - CHAP
T1 - Deformation-induced mechanical instabilities at the core-mantle boundary
AU - Petford, Nick
AU - Rushmer, Tracy
AU - Yuen, David A.
PY - 2007
Y1 - 2007
N2 - 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.
AB - 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.
UR - http://www.mendeley.com/research/deformationinduced-mechanical-instabilities-coremantle-boundary
U2 - 10.1029/174GM18
DO - 10.1029/174GM18
M3 - Chapter
SN - 9781118666401
T3 - Geophysical Monograph Series
SP - 271
EP - 287
BT - Geophysical Monograph Series
PB - Blackwell Publishing Ltd
ER -