Iceland is not a volcanic island formed from the atlantic and arctic rift, it is a continental island that is being torn apart by the rift zones, and will eventually be "engulfed" by the sea (more or less just merge into newly formed oceanic crust), which will (possible tomorrow, possibly millions of years from now) cause massive tsunamis and earthquakes.
Data: Continental crust beneath southeast Iceland (pnas.org, 2015)
http://www.pnas.org/content/112/15/E1818.full
So, iceland is a continental island, being torn apart. The earth's radius has been expanding since the archean earth, and all continents fit together on a smaller radius globe. The science which will supersede plate tectonics (as a proto-science) is one which, rather than trying to reconcile the data with a fixed radius, recognizes that it has been produced by an expanding radius earth.
The 21st century brings with it a number of scientific renaissances, one being the work of Dr. James Maxlow, who has spent 25 years producing content and models around expansion tectonics. Dr. Maxlow grew up in Australia, where it is natural to wonder about the Pacific ocean and how it relates to the earth's history.
