The Tharsis Montes Volcanoes

Volcanoes on Earth form due to plate tectonics causing the crust to move over upwelling magma plumes. However, Mars has no plate tectonics, and therefore its volcanoes should be extinct. Recent photos taken of Mars during the most recent missions have enough detail to allow scientists to theorize about a different method for the volcanoes to have formed. The type of shape and geology surrounding the volcanoes suggests that they may have been formed due to massive plasma discharges. These charges would have raised the topographically high volcanoes, and dug out the holes that created their calderas. The article asks if this should bring into question the plate tectonics theory on Earth?