Three years ago, I became very interested in Dr. James Maxlows' ideas and work around expansion tectonics.

Within Dr. James Maxlows' expansion tectonics, as I've understood it, the continental shelf formed from during early expansion of the earth, breaking apart the globe, with early oceanic basins formed, where the ocean floor was the continental shelf.

For an introduction to Dr. Maxlows' work, have a look at his PhD thesis from 2001, Quantification of an Archaean to Recent Earth Expansion Process Using Global Geological and Geophysical Data Sets.

The oceanic crust, the atlantic and pacific ocean, where formed later (Wikipedia), during the mesozoic and cenozoic era (250 mya - present) and so the continental shelf fits together on a smaller earth, as does the continents themselves.

Why is Iceland surrounded by continental shelf?

Iceland is surrounded by continental shelf, which suggests that it was around before the oceanic crust formed. The atlantic rift, and the rift zone north of Iceland, may then be two separate rifting zones, where the Greenland, Iceland, Europe continental crust and shelf is strong enough to separate the two rift zones.

There would still be a strong pull on Iceland, and volcanic activity, but the origin of the crust itself (at least below the magmatic, younger crust) would be older.

Could Iceland be "swallowed" if the rift zone broke through?

If Iceland is actually a part of the continent and not formed by volcanism, could it then be "swallowed" by the rift zone, if it were to break through the continental island?

Looking at the legend of Atlantis, which Plato in Timaeus described as a continent west of the Strait of Gibraltar that sank into the sea, the Azore Plateu is also positioned between multiple rift zones. Could Atlantis perhaps have been a continental island, surrounded by continental shelf, that originally separated these rift zones much like Iceland does today, and that was then torn apart and "swallowed" quite literally, only to leave some remains of the continent and the shelf, and volcanic islands?

Synapses

Deeply buried continental crust under Iceland - ScienceNordic.com

Fragment of continental crust found under southeast Iceland - phys.org