Papua New Guinea
The islands of Papua New Guinea form part of the Pacific region known as Melanesia. Occupying the northwestern regions of Melanesia, the islands of Papua New Guinea can be split in to two broad regions: the islands of the northeast and the islands of the southeast.
The islands of the northeast
consist of two major volcanic arc systems that line the northern, eastern and southern sides of the Bismarck Sea.
Geographically, most of the islands (except those in the east) are grouped together into the Bismarck Archipelago. The
islands of the east are an extension of the Solomon Islands.The northern arc extends from
Bougainville Island (9,318 km²) in the southeast through Buka (611 km²),
New Ireland (7,405 km²) and Lavaongai (1,190 km²) to
the Admiralty Islands in the west. The arc includes active volcanoes on Bougainville: Balbi
(2,715 m), Bagana (1,750 m), Loloru (1,887 m) and Billy Mitchell (1,544 m). The western end of the arc includes the
many islands of the Admiralty Islands group, dominated by the island of Manus (1,940 km²).
Off the eastern coast of New Ireland, running parallel to the coast at a distance of 30-50 km, is a second arc comprising the
islands of the Green, Feni, Tanga,
Lihir, and Tabar groups. The northern arc also contains many low-lying
islands and reefs and major barrier reef structures occur around Manus.
The second arc system runs through the large island of
New Britain (37,810 km²), with a string of major volcanoes running along the northern
coast of the island from Tavui and Rabaul in the east, through the Cape Hoskins and Willaumez Peninsula volcanoes of the
centre, to Langila in the west. The highest volcanoes on New Britain include Bamus (2,248 m) and Ulawun (2,334 m). From the
western end of New Britain the arc continues to the west with a series of islands formed by emergent stratovolcanoes,
including Umboi, Long Island, Karkar,
Manam, and the small islands of the Schouten Islands group.
The second major island grouping is that of the Southern Islands or Papuan Islands. They are essentially a continuation
of the Central Cordillera mountain range that runs through central New Guinea. As the range passes through New Guinea it
becomes lower towards the southeast, eventually forming the Owen Stanley Range (Mount Victoria, 4,072 m), the Papuan Peninsula,
the islands of the D'Entrecasteaux group and the Louisiade Archipelago;
dividing the waters of the Coral Sea (on the south) from those of the Solomon Sea (on the north). These
islands are thus submerged sections of the New Guinea central mountain system. Major islands in this region include
Fergusson Island (1,437 km²), Normanby Island (1,040 km²),
Vanatinai (867 km²), Goodenough Island (687 km²),
Rossel (262 km²), and Misima (202 km²). The islands are reef-fringed
and mountainous, rising to 2,536 m above sea level at Mount Vineuo on Goodenough Island.
Also in this area are a profusion of smaller islands, large and small reef systems, shoals and banks. Major examples include the islands and reefs of the Conflict Group, Engineer Group and the Siriki Shoals region. The dominant reef features in the area are the large barrier reef structures around the islands of Vanatinai and Rossel, and the 125 km long Bramble Haven-Long Reef-Anchorage Reefs formation.
North from these mountainous islands, extending in to the waters of the Solomon Sea, are the many islands of the geologically complex Woodlark Basin region. Major islands here include the Woodlark Islands, the Trobriand Islands and the Marshall Bennett Islands. Located upon a subducting plate, the region features many raised islands and raised carbonate platforms, atolls, and major reef formations such as those of the Lusancay Reefs and Star Reefs.