Hinchinbrook Island

Hinchinbrook

Hinchinbrook Island looking west (i-cubed Landsat 7).
Hinchinbrook
Geography
Location	Coral Sea
Coordinates	18°13′46″S 146°13′58″E / 18.22944°S 146.23278°E / -18.22944; 146.23278
Total islands	great barrier reef
Area	393 km2 (152 sq mi)
Length	52 km (32.3 mi)
Width	10 km (6 mi)
Highest elevation	1,121 m (3,678 ft)
Highest point	Mount Bowen
Administration
Australia
State	Queensland
LGA	Cassowary Coast Region

Hinchinbrook Island lies east of Cardwell and north of Lucinda, separated from the northern coast of Queensland, Australia by the narrow Hinchinbrook Channel. Hinchinbrook Island is part of the Great Barrier Reef Marine Park and wholly protected within the Hinchinbrook Island National Park, except for a small and abandoned resort. It is the largest island on the Great Barrier Reef. It is also the largest island national park in Australia.

Hinchinbrook Island is made up of late Palaeozoic igneous rocks. The main 16-kilometre-long (9.9-mile) pluton in the east of the island, the Hinchinbrook Granite, is composed of various hypersolvus granites and intrudes volcanics, granodiorites, and granites. The island and coastal ranges are thought to have been thrust up as blocks with subsidence between them to form the coastal plain with the summit level of the island being an older dissected surface that has been uplifted to approximately 1 kilometre (0.62 miles) or more above sea level. The Hinchinbrook Channel that separates the island from the mainland is considered to be fault controlled.

Since the last Ice Age 18,000 years ago sea level has risen. Once there was a significant rugged coastal range, now there is Hinchinbrook Island. To the west is the mangrove-fringed Hinchinbrook Channel with 164 km² of robust mangrove estuaries. The channel is the valley of the Herbert River flooded following the last glacial period. The island is only separated from the mainland at times of high sea-level such as the present and is thought to have had dry land connections to the mainland for most of the past few million years. Further west is the Cardwell Range Escarpment rainforest. East of Hinchinbrook Island lies the Coral Sea, Great Barrier Reef Lagoon and Great Barrier Reef.