Theory of the drift of asymmetrically-heated lithospheric plates

An approximate solution to the problem of the drift of a raft formed of two parallel wires, differentially heated, rigidly coupled and floating in a fluid of finite thickness and with linear viscosity, has been obtained and is shown to agree well with experiment up to a multiplicative constant. In addition, the solution to the problem of the drift of a solid raft with a suspended single-wire heater also shows good agreement with experiment up to a multiplicative constant. In both cases, the rafts drift with constant velocity. For small amounts of heat, the drift velocity is proportional to the first power of the heat input; for large amounts of heat, the drift velocity is proportional to the square root of the heat input. Within imponderable factors of an order of magnitude, the drift velocities are appropriate for drift of lithospheric plates containing both an oceanic and a continental part.