HR: 12:05h
AN: S11G-08    [PDF]
TI: D'' Layer Activation via Tidal Dissipation: A Link Between Non-Hydrostatic Ellipticity, Non-Chondritic Heat Flux, and Non-Plume Head Generation of Flood Basalts
AU: * Hager, B H
EM: bhhager@mit.edu
AF: Massachusetts Institute of Technology, 54-622 MIT, Cambridge, MA 02139
AU: Mazarico, E
EM: mazarico@mit.edu
AF: Massachusetts Institute of Technology, 54-622 MIT, Cambridge, MA 02139
AU: Touma, J
EM: jt00@aub.edu.lb
AF: American University of Beirut, P.O. Box 11-0236, Beirut, 11026 Lebanon
AU: Wisdom, J
EM: wisdom@mit.edu
AF: Massachusetts Institute of Technology, 54-622 MIT, Cambridge, MA 02139
AB: Quantitative understanding of Earth's heat budget has eluded a list of distinguished physicists and geochemists ranging from Lord Kelvin to Don L Anderson. The global heat flux is substantially greater than that generated by the estimated inventory of radioactive heat sources, so simple energy balance considerations demand an additional heat source. Secular cooling is commonly invoked to balance Earth's energy budget, but the required cooling rates are difficult to reconcile with both traditional convection calculations and petrologic estimates of ancient upper mantle temperatures. A non-geochemical heat source seems plausible. Indeed, Tuoma and Wisdom (Astron. J., 122, 2001) showed that tidal dissipation of rotational energy associated with resonant coupling could provide a substantial heat pulse to the CMB. D'' Layer Activation (DLA) by dumping of rotational energy could have important geodynamical consequences that we explore here. DLA could lead to a sudden (but modest) increase in the temperature of preexisting plumes, leading to a sudden increase in melt volume without the need for a troublesome plume head. The dissipation depends on non-hydrostatic CMB ellipticity, which itself is a result of mantle convection, leading to the possibility of an important feedback mechanism - DLA would lead to an increase in CMB ellipticity, further increasing the geodynamic importance of DLA.
DE: 1239 Rotational variations
DE: 5418 Heat flow
DE: 5450 Orbital and rotational dynamics
DE: 8115 Core processes (1507)
DE: 8130 Heat generation and transport
SC: Seismology [S]
MN: 2003 Fall Meeting