Bonin Islands Pacific Plate is subducting under the Philippine Sea Plate, which creates an oceanic trench to the east of the islands: the Bonin Trench. The crust of the Ogasawara Islands was formed by volcanic activity when subduction began 45–50 million years ago, and is composed mostly of an andesitic volcanic rock called boninite, which is rich in magnesium oxide, chromium, and silicon dioxide. The Ogasawara Islands may represent the exposed parts of an ophiolite that has not yet been emplaced on oceanic crust. The rocks of the Volcano Islands are much younger; Iwo Jima is a dormant volcano characterized by rapid
Islands of the Clyde etymology of Arran is no more clear—Haswell-Smith (2004) offers a Brythonic derivation and a meaning of "high place" although Watson (1926) suggests it may be pre-Celtic. Islands of the Clyde The Islands of the Firth of Clyde are the fifth largest of the major Scottish island groups after the Inner and Outer Hebrides, Orkney and Shetland. They are situated in the Firth of Clyde between Ayrshire and Argyll and Bute. There are about forty islands and skerries, of which only four are inhabited and only nine larger than . The largest and most populous are Arran and Bute, and Great