EVOLUTION OF THERMAL STRUCTURES BENEATH A SUBDUCTION ZONE

Thermal models of the subducting lithosphere and the surrounding mantle are investigated simultaneously. In the model, slab subduction is treated as a kinematic process. Subduction angle and subduction velocity are prescribed. The mantle is permitted to respond dynamically to subduction. Mantle flow is driven by both mechanical shearing and thermal buoyancy. Finite difference numerical techniques are utilized to model the subduction process. Results indicate that the descending lithosphere and the induced flow in the wedge area dictate the thermal structure beneath plate convergent regions. The temperature of a slab is found to be insensitive to the mantle condition prior to slab subduction. Viscous shear heating effects within the dynamic mantle are found to be important in maintaining a high temperature region immediately beneath the inter-arc basins. © 1979.