Banc du Geyser

Banc du Geyser is a mostly submerged, oval-shaped reef in the northeastern Mozambique Channel, about 125 kilometers northeast of Mayotte, 112 kilometers southwest of the Glorioso Islands and 200 kilometers off the northwestern coast of Madagascar. It measures about 8 kilometers long and 5 kilometers wide and is exposed only at low tide, apart from rock outcroppings in its southern portion, the highest of which, South Rock, rises 8 meters above the water. The reef is uninhabited but hosts large seabird colonies and guano deposits on its small sandy cays, and it takes its name from the British vessel Geysir, which ran aground there in 1678. It is also the subject of a three-way territorial dispute, administered by France as part of the Glorioso Islands' exclusive economic zone but claimed by both the Comoros and Madagascar, the latter having announced its annexation in 1976 amid the prospect of offshore petroleum resources.