Cosmogenic burial dating
The reason for this is because the plates themselves are not internally strong enough for forces along their edges to be transmitted across the entire plate.In other words, pulling or pushing forces would crush or fracture the crust before the forces could be transmitted to the rest of the plate.The existence of deep continental roots and the absence of a continuous, global asthenosphere to "lubricate" plate motions, have rendered the classical model of plate movements untenable.There is no consensus on the thickness of the "plates" and no certainty as to the forces responsible for their supposed movement.
As it turns out, the plates are not really solid, intact, plates at all, but are instead composed of broken-up pieces of various shapes, sizes, structure, and strength.
This might seem like an obvious expectation, except for the fact that it is not observed in real life.
The ocean trenches do not have enough sediment in them if subduction has truly occurred in these areas over the course of millions of years.
Based on this problem Pavlenkova concludes: "This means that the movement of lithospheric plates over long distances, as single rigid bodies, is hardly possible.
Moreover, if we take into account the absence of the asthenosphere as a single continuous zone, then this movement seems utterly impossible." She states that this is further confirmed by the strong evidence that regional geological features, too, are connected with deep (more than 400 km) inhomogeneities and that these connections remain stable during long periods of geologic time; considerable movement between the lithosphere and asthenosphere would detach near-surface structures from their deep mantle roots." The very process or "driving force" of plate movement is also coming under fire.
Of course, subduction does not happen for the edges of plates that are largely continental because continental crust cannot be subducted due to its relatively low density.