Geography of New Caledonia - Composition

Composition

New Caledonia is made up of a main island, the Grande Terre, and several smaller islands, the Belep archipelago to the north of the Grande Terre, the Loyalty Islands to the east of the Grande Terre, the (Isle of Pines) to the south of the Grande Terre, the Chesterfield Islands and Bellona Reefs further to the west. Each of these four island groups has a different geological origin:

• The New Caledonia archipelago, which includes Grande Terre, Belep, and the Île des Pins was born as a series of folds of the earth's mantle between the Permian period (299-251 mya) and the Tertiary period (65-1.5 mya). This mantle obduction created large areas of peridotite and a bedrock rich in nickel.
• The Loyalty Islands, a hundred kilometers to the east, are coral and limestone islands built on top of ancient collapsed volcanoes originating due to subduction at the Vanuatu trench.
• The Chesterfield Islands, 550 km to the north-west, are reef outcroppings of the oceanic plateau.
• The Matthew and Hunter Islands, at 450 and 520 km east, respectively, are volcanic islands that form the southern end of the arc of the New Hebrides

The Grande Terre is by far the largest of the islands, and the only mountainous island. It has an area of 16,372 square kilometres (6,321 sq mi), and is elongated northwest-southeast, 350 kilometres (217 mi) in length and 50 to 70 kilometres (31–44 mi) wide. A mountain range runs the length of the island, with five peaks over 1,500 meters (4,900 ft). The highest point is Mont Panié at 1,628 meters (5,341 ft) elevation. The total area of New Caledonia is 19,060 km2 (7,360 sq mi), 18,575 km2 (7,172 sq mi) of those being land.

A territorial dispute exists with regard to the uninhabited Matthew and Hunter Islands, which are claimed by both France (as part of New Caledonia) and Vanuatu.