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
Geography of the Marshall Islands famous World War II battle ground, is now used as a US missile test range; the island city of Ebeye is the second largest settlement in the Marshall Islands, after the capital of Majuro, and one of the most densely populated locations in the Pacific. This is a list of the extreme points of the Marshall Islands, the points that are farther north, south, east or west than any other location. Geography of the Marshall Islands The Marshalls consist of 29 atolls and five isolated islands, which form two parallel groups—the "Ratak" (sunrise) chain and the "Ralik" (sunset) chain. The