For what it's worth, I am fairly sure that shield, if implemented, would work like ME3's implementation of their own biotic shield.
You see it in many cutscenes and even certain stages with it completely blocking enemy fire. ME3 lets you actually use it in multiplayer and it creates a zone which grants increased defense, offense and other things, which is most likely how I see it working for us in that case they add it as well.
Which, given some uncertain and most probably wrong information I heard about, means it'd probable be an Arcanist spell (I hear arcanist were originally planend to use 'trap tiles' and stuff)