The maximum depth of the continental deep subduction: results from numerical simulation.

Two-dimensional numerical simulation for continental subduction by means of a finite element model of 8 visco-elastic material blocks with a given temperature field indicates that under the combined action of three kinds of dynamic load including the negative buoyancy, the push force of the mid-ocean ridge 10 similar to 30MPa from upper to lower and the drag force connected with mantle convection 100MPa, the actual vertical displacement of the subducted continental crust can reach 117km and its final subduction depth is 147km; the corresponding data for the subducted oceanic crust are 162km and 231km, respectively. Before the continental and oceanic crusts are subducted to a certain depth, their subduction speed basically keeps from varying, it is shown that their bottom displacement-time history curve is a straight line approximately; however, after subduction time is larger than 9Ma and the subduction depths of the continental and oceanic crusts reach 96km and 167km respectively, their subduction speed becomes gradually slower.