Reply #46: As for the part about connection to tectonic plates

[14thColony]

If it's Iceland, then the answer is often 'yes' since what we call Iceland is just the largest part of the Mid-Atlantic Ridge that's managed to grow above sea level. The Azores are another above-water part. The Mid-Atlantic Ridge divides two massive tectonic plates, and is the point from which the Atlantic seafloor is expanding east and west, pushing Eurasia and North America apart.

But at the same time I seem to recall that Iceland may owe its particularly rapid growth (the island's not that old) to coincidentally also being on top of a deep-mantle magma plume, the same kind thought to be the engine behind the Yellowstone super-volcano. So in this case, tectonic activity vs. mantle plume...I suppose it could be either or both or one might compliment the other. I would think the chemical composition of the magma might tell them. IIRC deep-mantle magma is chemically different from stuff originating in the upper mantle.