Linked from
The 16 pages that link to Island arc, each with the reason it gives.
Continental crustRelated: Arc magmatism produces material that can be added to growing continents.
Mariana TrenchRelated: The Mariana Islands are the volcanic arc paired with the trench.
Greenstone beltRelated: Arc volcanism is one proposed source of some belt rocks.
Superior CratonRelated: Arc volcanism produced rocks later incorporated into Superior crust.