Lihir Island
Papua New Guinea · Oceania
About
Lihir Island (a.k.a. Niolam Island) is the largest island in the Lihir group of islands, 22 km (14 mi) long and 14.5 km (9.0 mi) wide, in Papua New Guinea's New Ireland Province. It consists of a complex of several overlapping basaltic stratovolcanoes rising 700 m (2,300 ft) above sea level. While the volcanoes are not currently active, geothermal activity is still present. The island is in what was the forearc basin associated with the subduction of the Pacific Plate beneath the North Bismarck Plate. Subduction stopped about 10 million years ago with the collision of the Ontong Java Plateau with the subduction zone.
The name Lihir comes from the Patpatar language, cognate of the native name Lir. Niolam, also spelled Nualam or Nuolam, means "big island" (nua "island" + lam "big").
The island is located 900 km (560 mi) north east of Port Moresby. Annual rainfall averages 4,800 mm (190 in); temperature ranges between 19 and 35 °C (66 and 95 °F). The population of the Lihir Group increased from 12,570 in 2000 to an estimated 25,608 in 2011. Residents are of Melanesian descent and have predominantly a subsistence lifestyle.
Lihirians follow traditional belief systems, although official census records indicate that 99% of the PNG population are Christians, with Catholicism being the largest denomination. Most villages are located on the coastal fringe, although it is thought that originally some villages were located inland but were moved to the coast at the encouragement of missionaries.
The economic focal point of the island is the Lihir Gold Mine. Lihir represents one of the largest epithermal gold deposits in the world and it is hosted by high-potassic igneous rocks. The mine is operated by Newmont. The mine holds one of the world's largest gold resources (46 million ounces (1.3 billion grams)). Grab samples from the submarine Conical Seamount, located about 8 km (5.0 mi) south of Lihir Island, contain high gold concentrations of up to 250 g/t (9.0 oz/long ton) Au (avg. 26 g/t (0.93 oz/long ton), n=40) that are hosted by high-potassic trachybasalts.
Adapted from Wikipedia (CC BY-SA)。Photography via Wikimedia Commons.