這篇GEOG NEWS

I Think...( I don't know some of them too)
slabs (portions of plates that extend down into the Earth) drive convection in Earth's mantle, and ultimately the motion of the surface plates, but it hasn't been well established exactly how that happens---the ideas have been fairly vague," says Clinton Conrad, a postdoctoral fellow in the department of geological sciences.

There are two main ways these sinking slabs might influence plate motion. If a slab is attached to a plate, the slab can directly pull the plate toward the subduction zone.
A slab that is not well attached to a plate, can't pull directly on the plate. Instead, as it sinks, it sets up circulation patterns in the mantle that exert a sort of suction force, drawing nearby plates toward the subduction zone much as floating toys are drawn toward the outlet of a draining bathtub.

The model also explained an observation that has baffled geodynamicists for some time. "The way the observation was originally framed was that plates that have continents on them are slow, compared to plates that are only oceanic

2006-10-13 21:05:50 補充：
The main idea Suction and pull drive movement of Earth's plates

it is talk about the mainland and the moutain