 This part of the mid-ocean ridge is located above a mantle plume, causing Iceland to be subaerial (above the surface of the sea).The ridge marks the boundary between the Eurasian and North American Plates, and Iceland was created by rifting and accretion through volcanism along the ridge.Many fjords punctuate Iceland's 4,970-km-long (3,088-mi) coastline, which is also where most settlements are situated.