Perth Canyon
Encyclopedia
Perth Canyon is a submarine canyon
located on the edge of the continental shelf
off the coast of Fremantle, Western Australia
, approximately 22 kilometres (13.7 mi) west of Rottnest Island
. It was carved by the Swan River
, probably before the Tertiary
, when this part of the continental shelf was above sea level. It is an average of 1.5 kilometres (4,921.3 ft) deep and 15 kilometres (9.3 mi) across, making it similar in dimension to the Grand Canyon
.
It occupies an area of 2900 square kilometres (1,119.7 sq mi) and ranges in depth from 700 to 4000 m (2,296.6 to 13,123.4 ft). Within a few kilometres its depth drops from 200 metres (656.2 ft) down to 1000 metres (3,280.8 ft), and then it continues as a deep gully all the way out to the 4,000-metre depth, which is about another 30 kilometres (18.6 mi) farther west. It contains the world’s largest plunge pool
– a depression in the canyon which is 2 kilometres (1.2 mi) long, 6 kilometres (3.7 mi) across, and 300 metres (984.3 ft) deep.
The Perth Canyon is a feeding ground for pygmy blue whale
s, especially at the rims of the abyss. It is also a training ground for the Royal Australian Navy Submarine Service
, stationed at a naval base at nearby Garden Island
.
In June 2006 the waters around the Perth Canyon were the site of an ocean vortex
200 kilometres (124.3 mi) in diameter and 1000 metres (3,280.8 ft) deep. It was visible from space, and scientists claimed at the time that it had the potential to affect the local climate and the climate further abroad. The vortex was described by scientists as a marine "death trap", as it sucked in fish larvae.
Submarine canyon
A submarine canyon is a steep-sided valley on the sea floor of the continental slope. Many submarine canyons are found as extensions to large rivers; however there are some that have no such association. Canyons cutting the continental slopes have been found at depths greater than 2 km below sea...
located on the edge of the continental shelf
Continental shelf
The continental shelf is the extended perimeter of each continent and associated coastal plain. Much of the shelf was exposed during glacial periods, but is now submerged under relatively shallow seas and gulfs, and was similarly submerged during other interglacial periods. The continental margin,...
off the coast of Fremantle, Western Australia
Fremantle, Western Australia
Fremantle is a city in Western Australia, located at the mouth of the Swan River. Fremantle Harbour serves as the port of Perth, the state capital. Fremantle was the first area settled by the Swan River colonists in 1829...
, approximately 22 kilometres (13.7 mi) west of Rottnest Island
Rottnest Island
Rottnest Island is located off the coast of Western Australia, near Fremantle. It is called Wadjemup by the Noongar people, meaning "place across the water". The island is long, and at its widest point with a total land area of . It is classified as an A Class Reserve and is managed by the...
. It was carved by the Swan River
Swan River (Western Australia)
The Swan River estuary flows through the city of Perth, in the south west of Western Australia. Its lower reaches are relatively wide and deep, with few constrictions, while the upper reaches are usually quite narrow and shallow....
, probably before the Tertiary
Tertiary
The Tertiary is a deprecated term for a geologic period 65 million to 2.6 million years ago. The Tertiary covered the time span between the superseded Secondary period and the Quaternary...
, when this part of the continental shelf was above sea level. It is an average of 1.5 kilometres (4,921.3 ft) deep and 15 kilometres (9.3 mi) across, making it similar in dimension to the Grand Canyon
Grand Canyon
The Grand Canyon is a steep-sided canyon carved by the Colorado River in the United States in the state of Arizona. It is largely contained within the Grand Canyon National Park, the 15th national park in the United States...
.
It occupies an area of 2900 square kilometres (1,119.7 sq mi) and ranges in depth from 700 to 4000 m (2,296.6 to 13,123.4 ft). Within a few kilometres its depth drops from 200 metres (656.2 ft) down to 1000 metres (3,280.8 ft), and then it continues as a deep gully all the way out to the 4,000-metre depth, which is about another 30 kilometres (18.6 mi) farther west. It contains the world’s largest plunge pool
Plunge pool
A plunge pool can be a natural hydrologic fluvial landform feature or a constructed recreational garden feature...
– a depression in the canyon which is 2 kilometres (1.2 mi) long, 6 kilometres (3.7 mi) across, and 300 metres (984.3 ft) deep.
The Perth Canyon is a feeding ground for pygmy blue whale
Pygmy Blue Whale
The pygmy blue whale is a subspecies of the blue whale found in the Indian Ocean and the southern Pacific Ocean....
s, especially at the rims of the abyss. It is also a training ground for the Royal Australian Navy Submarine Service
Royal Australian Navy Submarine Service
The Royal Australian Navy Submarine Service is the collective name of the submarine element of the Royal Australian Navy. The service currently forms the Navy's Submarine Force Element Group and consists of six Collins class submarines....
, stationed at a naval base at nearby Garden Island
Garden Island (Western Australia)
Garden Island is a slender island about ten kilometres long and one and a half kilometres wide, lying about off the Western Australian coast, to which it is now linked by a man-made causeway....
.
In June 2006 the waters around the Perth Canyon were the site of an ocean vortex
Vortex
A vortex is a spinning, often turbulent,flow of fluid. Any spiral motion with closed streamlines is vortex flow. The motion of the fluid swirling rapidly around a center is called a vortex...
200 kilometres (124.3 mi) in diameter and 1000 metres (3,280.8 ft) deep. It was visible from space, and scientists claimed at the time that it had the potential to affect the local climate and the climate further abroad. The vortex was described by scientists as a marine "death trap", as it sucked in fish larvae.