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
History of the Falkland Islands the islands during the war. The purpose of the expecition was to assert Britain's claims on the continent, as well as gather scientific data. Operation Tabarin was later replaced by the Falkland Islands Dependencies Survey (FIDS), which was later renamed the British Antarctic Survey (BAS). In 1942, in response to the Japanese entry into the war, additional forces were sent to the islands to strengthen their defence against invasion. The largest component of these additional forces was a battalion of the West Yorkshire Regiment. In 1944, as a result of the reduced threat of invasion from Japan, the West Yorks