Ducie Island - Geography

Geography

Ducie lies 290 miles (470 km) east of Pitcairn Island and is claimed by some to be the southernmost atoll in the world at 24 degrees south latitude. However, Middleton Reef is at 29 degrees south latitude, so the assertion on behalf of Ducie Island is doubtful. Ducie Island's land area is 170 acres (1 km2) and its maximum elevation, occurring on the Westward islet, is 15 feet (4.6 m).

Ducie is located 620 miles (1,000 km) west of the edge of the Easter Plate. It was formed approximately 8 million years ago, after Oeno Island was formed by a hotspot that later caused a magma leak generated in the Oeno lineation. The leak spread over fracture zone FZ2, which was formed by the third movement of the Pacific Plate. The atoll is part of the Oeno-Henderson-Ducie-Crough seamount, speculated to be part of the southern Tuamotus.

The atoll consists of four islets: Acadia, Pandora, Westward and Edwards. The last three of these can be accessed on foot from Acadia at low tide. The islets were named by Harald Rehder and John Randall, who visited the atoll during an expedition by the Smithsonian Institution in 1975.

• Acadia Islet, along the atoll's north and east rim, is larger than the other three islets combined, measuring 140 acres (55 hectares). Very long and thin, the islet is largely forested and is composed of ridges of coral rubble. It is named after the Acadia, a ship that was wrecked on Ducie in 1881.
• Pandora Islet, in the south, is the second largest. It is composed of sand and coral rubble that borders the lagoon. It is named after HMS Pandora.
• Edwards Islet lies immediately to the east of Pandora Islet and has the same characteristics. It is named after Edward Edwards, captain of HMS Pandora.
• Westward Islet, west of Pandora Islet, is the smallest. It appears sandy from a distance, but the soil is composed of coral rubble and dead shells. Its highest point rises 15 feet (4.6 m) above average sea level. It is named after the Westward, the ship that carried the members of the National Geographic Society and the Oceanic Institute during their 1970–71 expedition.

The atoll has a central lagoon, accessible by boat only by way of a channel 100 yards (91 m) wide located in the southwest, between Pandora and Westward Islets. It has a maximum depth of 52 feet (16 m) and its bottom consists of sand and coral. Whirlpools in the lagoon are common, caused by tunnels that drain the water from the lagoon into the ocean.