Geology of the British Indian Ocean Territory carbonates, which are present in the Seychelles for reasons that are not clear—hypothesized to include local storm erosion. The offshore waters around the archipelago contain deep-sea ferromanganese nodules, with globular, dendritic and laminated microstructures formed from iron-manganese oxide. Due to the US military presence on the island the US Geological Survey has conducted water resource analysis since 1984. Geology of the British Indian Ocean Territory The geology of the British Indian Ocean Territory comprises the Chagos Archipelago—the above water portion of the Chagos Bank. Formed from hotspot volcanism, the Chagos Bank was separated from the Nazareth Bank 36 million years
Geography of the British Indian Ocean Territory Australia). Diego Garcia lies at the southernmost tip of the Chagos-Laccadive Ridge — a vast submarine range in the Indian Ocean. The total area encompassed by the atoll is . At the entrance to the lagoon, there are three small islands, and these are East Island (), Middle Island (), and West Island (). In some areas, the atoll has both marshes and wetlands. The ecosystem consists of undisturbed tropical forests. The Peros Banhos Islands, which are the largest group on the Chagos Bank, consists of 27 islands scattered around the rim of an immense lagoon, which has a perimeter