Perth Canyon is a

submarine canyon A submarine canyon is a steep-sided valley cut into the seabed of the continental slope, sometimes extending well onto the continental shelf, having nearly vertical walls, and occasionally having canyon wall heights of up to , from canyon flo ...

located on the edge of the

continental shelf A continental shelf is a portion of a continent that is submerged under an area of relatively shallow water, known as a shelf sea. Much of these shelves were exposed by drops in sea level during glacial periods. The shelf surrounding an islan ...

off the coast of

Perth, Western Australia Perth () is the list of Australian capital cities, capital city of Western Australia. It is the list of cities in Australia by population, fourth-most-populous city in Australia, with a population of over 2.3 million within Greater Perth . The ...

, approximately west of

Rottnest Island Rottnest Island (), often colloquially referred to as "Rotto", is a Islands of Perth, Western Australia, island off the coast of Western Australia, located west of Fremantle. A sandy, low-lying island formed on a base of aeolianite limestone, ...

. It was carved by the Swan River, likely before the

Tertiary Tertiary (from Latin, meaning 'third' or 'of the third degree/order..') may refer to: * Tertiary period, an obsolete geologic period spanning from 66 to 2.6 million years ago * Tertiary (chemistry), a term describing bonding patterns in organic ch ...

, when this part of the continental shelf was above sea level. It is an average of deep and across, making it similar in dimension to the

Grand Canyon The Grand Canyon is a steep-sided canyon carved by the Colorado River in Arizona, United States. The Grand Canyon is long, up to wide and attains a depth of over a mile (). The canyon and adjacent rim are contained within Grand Canyon Nati ...

. It occupies an area of and ranges in depth from . Within a few kilometres its depth drops from down to , and then it continues as a deep gully all the way out to the depth, which is about another further west. It contains the world's largest

plunge pool A plunge pool (or plunge basin or waterfall lake) is a deep depression in a stream bed at the base of a waterfall or Shut-in (river), shut-in. It is created by the erosion, erosional forces of cascading water on the rocks at the formation's bas ...

a depression in the canyon that is long, across, and deep. The canyon is considered "a perfect spot" for deep sea fishing. The Perth Canyon is a feeding ground for

pygmy blue whale The pygmy blue whale (''Balaenoptera musculus brevicauda'') is a subspecies of the blue whale (''Balaenoptera musculus'') found in the Indian Ocean and the Southern Pacific Ocean. Taxonomy The pygmy blue whale formed from a founder group of An ...

s, especially at the rims of the abyss. It is also a training ground for the

Royal Australian Navy Submarine Service The Royal Australian Navy Submarine Service is the submarine element of the Royal Australian Navy. The service currently forms the Navy's Submarine Force Element Group (FEG) and consists of six ''Collins'' class submarines. The Royal Australi ...

, stationed at a naval base at nearby

Garden Island A garden is a planned space, usually outdoors, set aside for the cultivation, display, and enjoyment of plants and other forms of nature. The single feature identifying even the wildest wild garden is ''control''. The garden can incorporate both ...

. In June 2006, the waters around the Perth Canyon were the site of an ocean

vortex In fluid dynamics, a vortex (: vortices or vortexes) is a region in a fluid in which the flow revolves around an axis line, which may be straight or curved. Vortices form in stirred fluids, and may be observed in smoke rings, whirlpools in th ...

in diameter and 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.

References

Landforms of Western Australia Submarine canyons of the Indian Ocean {{WesternAustralia-geo-stub

See also

References