Pit of Mariannes

See also: Marianne (homonymy)

The pit of Mariannes is the underwater Fosse deepest currently known, and the major place of the Earth's crust. It is located in the north-western part of the Pacific Ocean, in the east of the the Northern Marianna Islands to the coordinates, near the island of Guam. The point low is according to the statements between a little less: 11500 meters and a little more: 11000 meters of depth.

Origin and tectonic context

The pit is located on a border of tectonic plates, in a zone of Subduction where the Pacifique plate passes under the plate of Philippines. It is about a pit generated by spontaneous subduction in oceanic field: the subduction ocean-ocean is coupled with a basin back-arc in extension.

Exploration

The pit was studied for the first time in 1951 by the vessel of the Royal Navy Challenger II , which gave its name to the point low of the pit, Challenger Deep. Its depth was measured by echo survey, which gave like 10  result; 900 meters with the coordinates. Because the extreme different depth and Thermocline S crossed by the aural signal, thus disturbing the precision of the statement, the persons in charge of Royal Navy preferred to be careful at the time of their official press release, by declaring the depth of 10  863 meters.

In 1957, the vessel of the Soviet Union Vityaz , announces that the maximum depth of the pit is of 11  034 meters. This new bottom, called Mariana Hollow , forever been able to be redétecté and cannot thus be regarded as exact. In 1962, the Spencer F. Baird records 10  915 meters like maximum depth, followed in 1984 by Japan board on board the Takuyo , which raises a depth of 11  040,4. The most precise measurement is also of Japanese origin, thanks to the underwater probe Kaiko , which it March 24th 1995 raises a depth of 10  911 meters.

The January 23rd 1960, aboard bathyscaphe Trieste, the Swiss Jacques Piccard, wire of Auguste Piccard the inventor of the Bathyscaphe and the American lieutenant of U.S. Navy Gift Walsh, touch the bottom of the pit to 13:06, after a 4 hours descent 30 minutes. The instruments indicate a depth of 11  521 meters, number which will be re-examined thereafter with the fall with 10  916 meters. With this depth, where the pressure is extreme, the two men are surprised to see, in the middle of the circle of light drawn by their projectors, a genuine abyssal fish resembling a plate of approximately 30 centimetres, as well as Crevette S. As at ease as their cousins of the watery luminous world, these inhabitants of the abyssals zone are the proof that the life on Ground does not know in-depth limit.

With regard to the pressure exerted by the tons of water to the top, the instruments raise 1  086 bars, is more 1  000 times existing pressure with the Sea level.

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