HR: 14:40h
AN: T13D-05 INVITED     [Abstracts]
TI: Evolution of plate tectonics, secular cooling of the Earth, and the global water cycle
AU: * Korenaga, J
EM: jun.korenaga@yale.edu
AF: Dept. of Geology and Geophysics, Yale University, PO Box 208109, New Haven, CT 06520 United States
AB: Plate tectonics is a surface manifestation of solid-state convection in the Earth's mantle. How plate tectonics has evolved through time is thus intimately connected to how the Earth has been cooled by mantle convection. The energetics of plate tecotnics is not simply that of thermal convection, because it is most likely affected by chemical differentiation processes associated with plate tectonics. Combined with the thermal history of the Earth, a recently-developed heat flow scaling law for plate tectonics indicates a gradual increase in the speed of global plate motion since the late Archean. This notion of more sluggish plate tectonics in the past appears to be consistent with the geological record of the Wilson cycle, and also has a potential to resolve several nagging issues in global geodynamics and geochemistry. In this presentation, I will also discuss an intriguing connection between the thermal evolution of the Earth and the history of ocean volume. The new evolution model of plate tectonics may provide a robust estimate on the long-term net water flux from the hydrosphere to the solid Earth.
DE: 8125 Evolution of the Earth
DE: 8130 Heat generation and transport
DE: 8162 Rheology--mantle
SC: Tectonophysics [T]
MN: 2004 AGU Fall Meeting