I can’t even remember how it happened (perhaps it was triggered by sending a postcard to the French Overseas Department Réunion, which is an island off the coast of Madagascar, two days ago?), but I suddenly, very much needed to know how Bermuda, which lies in very isolated waters off the eastern coast of the United States, came to exist.
Answer: it is volcanic.
The Bermuda Pedestal is an oval geological feature in the northern Atlantic Ocean containing the topographic highs of the Bermuda Platform, the Plantagenet (Argus) Bank, and the Challenger Bank. The pedestal is 50 km (31 mi) long and 25 km (16 mi) wide at the 100 fathom line (-185 m), while the base measures 130 km by 80 km at -4200 m.
I don’t think of the east coast of the US as volcanic generally, and while it is quite a distance from shore, it still feels like a surprise. A theory of a Bermuda Hotspot is uncertain.
I know our Pacific Ring of Fire isn’t the only site of tectonic plate volcanism, but outside of Iceland (which is quite wildly and unmistakably and actively volcanic), “Atlantic” and “volcanic” aren’t ideas that go together for me.
If Réunion did plant the conceptual seed of this need to know, it is likely because (yes) it is also volcanic, and the island has not one but TWO volcanoes: one dormant and the other quite active.
Piton de la Fournaise ( French for “Peak of the Furnace”) is a shield volcano on the eastern side of Réunion island (a French department) in the Indian Ocean. It is currently one of the most active volcanoes in the world, along with Kīlauea in the Hawaiian Islands, Stromboli and Etna in Italy and Mount Erebus in Antarctica.
(Until sending this Réunion bound mail off, my prior association with Réunion was that a confirmed piece of missing flight plane MH-370 washed up there. )