Shear flow beneath oceanic plates: Local nonsimilarity boundary layers for olivine rheology
The principle of local similarity, which has been used to model the two-dimensional boundary layers in the oceanic upper mantle, permits calculation of the temperature, velocity, and stress fields with essentially analytic techniques. Finite difference numerical methods are hard pressed to resolve the detail required by the large variation of viscosity between the lithosphere and the asthenosphere. In this paper the local similarity approximation has been justified by quantitatively evaluating the effect of nonsimilarity due to viscous heating, nonlinear temperature- and pressure-dependent rheology, buoyancy, adiabatic cooling, etc. Nonsimilar effects produce only small modifications of the locally similar boundary layers; important geophysical observables such as surface heat flux and ocean floor topography are given to better than 10% by the locally similar solution. A posteriori evaluations of the term neglected in the boundary layer simplification of the complete equations have been conducted on the locally similar temperature and velocity profiles close to the spreading ridge. The boundary layer models are valid to depths of 100 km at 3 m.y. and 10 km at 0.3 m.y.
- Research Organization:
- Department of Earth and Space Sciences, University of California, Los Angeles, California 90024
- OSTI ID:
- 5088571
- Journal Information:
- J. Geophys. Res.; (United States), Vol. 83:B2
- Country of Publication:
- United States
- Language:
- English
Similar Records
Mantle circulation with partial shallow return flow
Crustal and uppermost mantle structure near the Gloria Fault, North Atlantic, from ocean bottom seismometer surface wave observations
Related Subjects
EARTH MANTLE
BOUNDARY LAYERS
SEA BED
ADIABATIC PROCESSES
CONVECTION
MASS TRANSFER
OCEANOGRAPHY
OLIVINE
PRESSURE DEPENDENCE
STRESSES
TEMPERATURE DEPENDENCE
TOPOGRAPHY
TWO-DIMENSIONAL CALCULATIONS
ENERGY TRANSFER
HEAT TRANSFER
LAYERS
580500* - Oceanography- (1980-1989)
580100 - Geology & Hydrology- (-1989)