HR: 1340h
AN: T43B-1325 [Abstracts]
TI: A Reconstruction of Mantle Plume Evolution by Optimal Heat and Mass Transportation: Impact of Mantle
Diffusion and Viscosity
AU: * Ismail-Zadeh, A
EM: aismail@mitp.ru
AF: International Institute of Earthquake Prediction Theory and Mathematical Geophysics, Russian Academy of
Sciences, Warshavskoye sh. 79-2, Moscow, 117556
Russian Federation
AU: * Ismail-Zadeh, A
EM: aismail@mitp.ru
AF: Geophysical Institute,University of Karlsruhe, Hertzstr. 16, Karlsruhe, 76187
Germany
AU: Schubert, G
EM: schubert@ucla.edu
AF: Department of Earth and Space Sciences and Institute of Geophysics and Planetary Physics, University of
California, 3806 Geology Building, 595 Charles Young Drive East, Los Angeles, CA 90095-1567
United States
AU: Tsepelev, I
EM: tsepelev@imm.uran.ru
AF: Institute of Mathematics and Mechanics, Russian Academy of Sciences, S. Kovalevskaya 16, Yekaterinburg,
620219
Russian Federation
AU: Korotkii, A
EM: korotkii@imm.uran.ru
AF: Institute of Mathematics and Mechanics, Russian Academy of Sciences, S. Kovalevskaya 16, Yekaterinburg,
620219
Russian Federation
AB:
The ascent and evolution of mantle plumes depend on the properties of the source region and the viscosity and thermal
diffusivity of the ambient mantle. While mantle properties are relatively constant during a hundred Myr lifetime of most
plumes, source region properties can vary substantially with time as the thermal boundary layer feeding the plumes is
depleted of hot material. Complete local depletion of the boundary layer cuts the plumes off from their source. It is the
subsequent evolution of the plumes and the reconstruction of this evolution that interests us here. We study effects of the
heat diffusion on the evolution of mantle plumes at lower Rayleigh numbers ($Ra$). Numerical experiments show that a delay or
interruption in plume heat and mass transfer results in the diffusive disappearance of plume tails first and plume heads
later. This is the most likely explanation for the seismically detected mid-mantle plumes. We restore these diffused plumes
to their prominent states in the past and analyze the restoration errors for various $Ra$. Also we study the effect of the
lower viscosity of mantle plumes on their evolution and restoration.
DE: 8121 Dynamics, convection currents and mantle plumes
DE: 3210 Modeling
DE: 3230 Numerical solutions
DE: 3260 Inverse theory
SC: Tectonophysics [T]
MN: 2004 AGU Fall Meeting