Thermo-mechanical model of the mantle wedge in Central Mexican subduction zone and a blob tracing approach for the magma transport

Considering that the melting processes on and in the vicinity of the subducting plate surface generate the most of the volcanic material, a dynamic model for the blob tracers is developed using Stokes flow at infinite Prandtl number. The blobs of 0.2-10.0 km in diameter migrate along very different trajectories only at low wrapping viscosities (ηw = 1014-5 × 1017 Pa s). The modeling results show that the “fast” trajectories terminate at the same focus location at the base of the continental crust, while the arrival points of “slow” trajectories, which are common for the blobs of smaller size (∼0.4-0.5 km), are scattered away from the average focus location. This observation may give us a hint on a possible mechanism of strato and mono volcanoes genesis. The rise time, which the blob detached from the subducted plate, needs to reach the bottom of the continental crust, is from 0.001 up to 14 million years depending on the blob diameter and surrounding viscosity.