Open AccessThe Influence of the Boundary Conditions and Rotation on Convection in the Earth's Mantle *
Author(s) -
McKenzie D. P.
Publication year - 1968
Publication title -
geophysical journal of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0016-8009
DOI - 10.1111/j.1365-246x.1968.tb00203.x
Subject(s) - convection , geophysics , mantle convection , mantle (geology) , mechanics , geology , physics , nonlinear system , earth's rotation , zonal flow (plasma) , classical mechanics , convection cell , combined forced and natural convection , natural convection , geodesy , lithosphere , tectonics , paleontology , plasma , quantum mechanics , tokamak
Summary The external nonhydrostatic gravity field must be maintained by flow within the mantle. An analysis of axisymmetric poloidal circulation in a rotating compressible sphere shows it to be more important than was previously believed. However, such flow is probably unable to produce the observed nonhydrostatic equatorial bulge. The basic equations are nonlinear, but can be solved if the viscosity is sufficiently large. The conditions which must be satisfied before this approximation is valid are examined in some detail because of their relevance to convection in the mantle. The horizontal temperature differences between oceans and continents must also drive convection currents, though such flow can only be of local importance at present. Two‐dimensional convection driven by horizontal temperature variations can successfully account for most of the phenomena which are believed to be the surface expressions of flow in the mantle. The only exception is the gravity anomaly over the rising current, which is positive in the model. Though this linear theory is not self consistent, it does show that convection of heat is the only important nonlinear term. Further understanding of the problem will require numerical analysis.