Penguin Island (South Australia)

Penguin Island

View of Penguin Island from Cape Martin, South Australia
Penguin Island
Geography
Location	Rivoli Bay
Coordinates	37°29′54″S 140°00′50″E / 37.49839°S 140.01376°E / -37.49839; 140.01376Coordinates: 37°29′54″S 140°00′50″E / 37.49839°S 140.01376°E / -37.49839; 140.01376
Area	2.02 ha (5.0 acres)
Highest elevation	16 m (52 ft)
Administration
Australia
Demographics
Population	0

Penguin Island is an island in the Australian state of South Australia located in Rivoli Bay on the state's south east coast of approximately 1.5 kilometres (0.93 miles) south of Beachport. From 1878 to 1960, it was the site of an operating lighthouse. Since at least 1972, it has been part of the Penguin Island Conservation Park.

Penguin Island is located about 1.5 kilometres (0.93 miles) south of Beachport and about 120 metres (390 feet) south-east of the headland known as Cape Martin. The island consists of two outcrops which are reported as being unofficially known as Outer Penguin Island and Inner Penguin Island. The latter outcrop came into existence in 1968 when a storm caused the collapse of a section of Cape Martin thereby creating a channel of about 40 metres (130 feet) in width between the remains of the headland and an isolated stack of remnant cliff now known as Inner Penguin Island. Both outcrops are surrounded by vertical cliffs that rise to between 10 metres (33 feet) to 15 metres (49 feet) in height above sea level, with exception to the south-western end of the outer island where the ground falls steeply to a rocky spit. A wave cut platform surrounds most of the island. The major outcrop along with minor outcrops and submerged strata form an island which is about 400 metres (1,300 feet) long and up to 150 metres (490 feet) wide. The island is partially covered with sand which itself has partially developed in a soil. The inner island was reported in 1994 as being accessible by foot at low water while the outer island was only be accessed by boat or by swimming.

Penguin Island was formed about 6000 years ago when sea levels rose at the start of the Holocene. The island is composed of Bridgewater Formation calcareous sandstone which is a remnant of now partially submerged Robe Range which was formed during the . The island which is located in relatively shallow water rises from a depth of 10 m (33 ft) within 1,000 m (3,300 ft) to its west, 200 m (660 ft) to its south and 300 m (980 ft) to its east.