Volcanic activity / mountain ranges occur in front of the subducting zone / plate, and volcanic activity can also occur as a result of rifting apart.
If the North American plate bumps into Europe, something much more cataclysmic will be the cause. ;) As you know, my pet theory is a cyclic build of heat within earth (from tidal force and other), working its way up to the surface of the planet, and the increased geological activity worldwide, evidence. We had 75 volcanoes erupt in '12, we're already above 60 for '13.
The recent discovery of a larger than first determined hot spot in the Southern Pacific, and the magnetic pole drift picking up speed are other evidence.
I think the piece missing is how this new subduction area sets up. if it is subducting west to east then it will directly effect the atlantic ridge if it’s subducting say east to west I would think that would tend to cause the most havoc.