In geology (and sometimes in archaeology), a high island is an island of volcanic origin. The term can be used to distinguish such islands from low islands, whose origin is due to sedimentation or uplifting of coral reefs.
The Gambier Islands or Mangareva Islands (French: Îles Gambier or Archipel des Gambier) are a small group of islands in French Polynesia, located at the southeast terminus of the Tuamotu archipelago. They are generally considered a separate island group from Tuamotu both because their culture and language (Mangarevan) are much more closely related to those of the Marquesas Islands, and because, while the Tuamotus comprise several chains of coral atolls, the Gambiers are of volcanic origin. Because of their proximity, the Acteon Group, and the nearby atoll of Temoe ( ) are sometimes included among the Gambiers.