Christmas Island - Geography

Geography

Located at 10°30′S 105°40′E / 10.5°S 105.667°E / -10.5; 105.667, the island is a quadrilateral with hollowed sides, about 19 kilometres (12 mi) in greatest length and 14.5 km (9.0 mi) in extreme breadth. The total land area is 135 square kilometres (52 sq mi), with 138.9 km (86.3 mi) of coastline. The island is the flat summit of a submarine mountain more than 4,500 metres (14,800 ft) high, the depth of the platform from which it rises being about 4,200 m (13,780 ft) and its height above the sea being upwards of 300 m (984 ft). The mountain was originally a volcano, and some basalt is exposed in places such as The Dales and Dolly Beach, but most of the surface rock is limestone accumulated from the growth of coral over millions of years. "The summit of this mountain peak is formed of a succession of tertiary limestones ranging in age from the Eocene (or Oligocene) up to recent reef-deposits, with intercalations in the older beds of volcanic rocks."

Steep cliffs along much of the coast rise abruptly to a central plateau. Elevation ranges from sea level to 361 m (1,184 ft) at Murray Hill. The island is mainly tropical rainforest, of which 63% is National Park.

The narrow fringing reef surrounding the island can be a maritime hazard.

It is 2,600 kilometres (1,600 mi) northwest of Perth, Western Australia, 500 km (310 mi) south of Indonesia, 975 km (606 mi) ENE of the Cocos (Keeling) Islands, and 2,748 km (1,708 mi) west of Darwin, Northern Territory. Its closest point to the Australian mainland is 1560 km from the town of Exmouth, Western Australia.

The climate is tropical, with heat and humidity moderated by trade winds.