There was time when as the highest top of the world was considered the Everest (8848 m above sea level). But with expansion of our knowledge about a sea-bottom relief it was found out that a volcano of Mauna Kea on island Hawaii on 2300м above if to measure its height from an ocean floor.
That fact that the height of Mauna Kea together with an underwater part exceeds 10 000 m, - only one of many surprising opening made as a result of research of sea depths. Today by means of modern technologies cards of a bottom of the World ocean are made. They have helped scientists to prove that the oceanic bottom gradually extends. For example, a bottom of Atlantic ocean "Ёрёяюычрх=ё " in the parties from a median ridge with a speed of 2,5 sm a year.
Occurs spredints or raspolzanie a bottom, from other ridges even faster. So, on the East Pacific raising it reaches 12-16 sm a year. It does not mean that the ocean expands the possession for plates upon which its bottom is based, are gradually involved in deep a trench.
To One of the most amazing opening in studying of an underwater relief was that any stone which has fallen on an ocean floor or test of ground adjournment is not more senior 200 million has laid down. For comparison, the age of the most ancient continental breeds exceeds 3960 million years.
the Continental shelf
Smoothly going down part of underwater suburb of continent is called as a continental shelf. If at coast Chiles the shelf narrow enough - is no more 2 km - that in other places it occupies the huge areas. All North Sea represents a part of the European continental shelf, and the shelf along the Arctic coast of Siberia reaches at width more than 1 200 km.
On a continental shelf sea depths usually do not exceed 200 m. External edge, pli brovka, a shelf sharply breaks downwards to abissalnoj to plain, or an oceanic bottom. This continental slope is original border of continent.
Mostly absolutely flat abissalnaja the plain is deprived expressive relief forms. It lies on depth of 4000-5000 metres and is combined by the volcanic basalt breeds covered with a layer of ground adjournment. Ground adjournment consist of the rests of uncountable plants and animals. The majority of them - small, even the microscopic organisms living in thickness of water and named a plankton. Many representatives of a zooplankton have a limy skeleton or an armour from carbonic calcium, therefore the basis of ground adjournment is made by limy silt.
The plain Abissalnaja is dismembered by a number of the geological structures forming provinces of an oceanic bottom. In the central part of oceans underwater ridges where from cloak bowels it is pushed out upward lie and slowly the fused breed hardens. Here earth crust replenishes with a new material.
In due time scientists believed, what exactly this intruzija volcanic breeds has led to a divergence of plates of earth crust. Today we know that their movement occurs under the influence of other relief form of a sea-bottom - the deep trenches bordering edges of the next plates. Here plates are gradually involved back in bowels of a cloak for repeated absorption. On an ocean floor of such trenches it is a lot of, including along Pacific coast of the South America because of what and the shelf in these edges is very narrow.
Underwater mountains are formed in so-called "уюЁ ёш§ =юёър§" planets owing to eruptions of underwater volcanoes. The majority of islands of Silent and Atlantic oceans is their surface tops. One volcanoes have gone out for a long time, others - for example, Tristan da Cunha Islands and Canary Islands in Atlantic ocean. The Hawaiian and Philippine archipelagoes in Silent - actively operate or sleep.
sea-bottom Researches are conducted not one hundred years. Floating along coast, seamen measured depths by means of the lead weight adhered to a cable.
The Same method used and in a XIX-th century on British korvete "Охыыхэ-фцхЁ" which for 3,5 years of global cruise has collected weight of the scientific information on sea depths. Reports of this expedition have occupied 50 volumes.
In the pasha time a lot of the scientific information has been received thanks to work of a scientific vessel "+ыюьрЁ ОхыыхэфцхЁ" equipped with much more perfect equipment, than its well-known namesake. During the project of oceanic drilling begun in 1968 Dlomar ОхыыхэфцхЁ" has visited different corners of world ocean where buril chinks and selected for the analysis samples of breeds.
Sea-bottom Cards make by means of established onboard the ship deep-water eholotov which make gaugings of sea depths. More powerful signal low-frequency eholota is capable to get through the top layers of a ground ground and to give the information on the breeds located under them. The hydrolocators of the lateral review scanning district at an angle, distinguish structures of various layers of a sea-bottom. And, at last, by means of special deep-operating vehicles visual researches are conducted. Some devices work without crew, but are equipped by television cameras.