Mantle circulation with partial shallow return flow: Effects on stresses in oceanic plates and topography of the sea floor
Fully two-dimensional analytic boundary layer solutions are used to model the thermodmechanical structure of the oceanic upper mantle when a shallow horizontal return flow helps balance the lithospheric transport of mass from ridge to trench. The following are all incorporated in the solutions: horizontal and vertical advection of heat, vertical heat conduction, viscous dissipation, adiabatic heating and cooling, buoyancy, and the pressure- and temperature-dependent nonlinear rheology of olivine. Depth profiles of horizontal and vertical velocities, temperature, and shear stress are calculated for several ages of ocean floor. Such solutions are used to construct accurate isotherm and streamline patterns within the rigid lithosphere and high-shear, return flow asthenosphere of the oceanic upper mantle boundary layer. Ocean floor topography is inferred from the thermal contraction of the cooling lithosphere and asthenosphere and from the adverse horizontal pressure gradient required by the dynamics to drive the shallow return flow.
- Research Organization:
- Department of Earth and Space Sciences, University of California, Los Angeles, California 90024
- OSTI ID:
- 5078953
- Journal Information:
- J. Geophys. Res.; (United States), Vol. 83:B2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
EARTH MANTLE
MASS TRANSFER
SEA BED
TOPOGRAPHY
ADIABATIC PROCESSES
BOUNDARY LAYERS
CONVECTION
OCEANOGRAPHY
OLIVINE
PRESSURE DEPENDENCE
STRESSES
TEMPERATURE DEPENDENCE
THERMAL CONDUCTION
TWO-DIMENSIONAL CALCULATIONS
VELOCITY
ENERGY TRANSFER
HEAT TRANSFER
LAYERS
580500* - Oceanography- (1980-1989)
580100 - Geology & Hydrology- (-1989)