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The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continents of Asia and Australia in the west and the Americas in the east.
- 4,280 m (14,040 ft)
- 165,250,000 km² (63,800,000 sq mi)
- 10,911 m (35,797 ft)
- 710,000,000 km³ (170,000,000 cu mi)
- Overview
- Relief
- Principal ridges and basins
- Bottom deposits
- Islands
- Geology
The Pacific Ocean is a body of salt water extending from the Antarctic region in the south to the Arctic in the north and lying between the continents of Asia and Australia on the west and North America and South America on the east.
How far from north to south does the Pacific Ocean extend?
The Pacific Ocean stretches from the Bering Strait near the Arctic Circle to the shores of Antarctica through 135° of latitude, some 9,600 miles (15,500 km). The mean depth of the Pacific (excluding adjacent seas) is 14,040 feet (4,280 metres), and its greatest known depth is 36,201 feet (11,034 metres).
What is the temperature of the deep zone of the Pacific Ocean?
The deep zone of the Pacific Ocean, which contains about 80 percent of the ocean’s volume, has relatively stable temperature and salinity patterns; its average temperature is 38.3 °F (3.5 °C).
What is the salinity of the Pacific Ocean?
The Pacific basin may conveniently be divided into three major physiographic regions: the eastern, western, and central Pacific regions.
To the east of longitude 150° W, the relief of the ocean floor is considerably less pronounced than it is to the west. In the eastern Pacific the Cocos Ridge extends southwestward from the Central American isthmus to the Galapagos Islands. To the south of the Galapagos lies the Peru Basin, which is separated by the extensive Sala y Gómez Ridge from the Southeast Pacific Basin, which in turn is separated from the Southwest Pacific Basin by the East Pacific Rise and indeterminate Pacific-Antarctic Ridge, which runs from the Sala y Gómez Ridge to Antarctica in the vicinity of 150° W.
Extending southward from the Tasman Basin (between New Zealand and eastern Australia) is the Macquarie Ridge, which forms a major boundary between the deep waters of the Pacific and Indian oceans. The Hawaiian Ridge extends westward from Hawaii to the 180° meridian.
Apart from the narrow coastal zone of the eastern region and the broad continental seas of the western region, the Pacific is floored with pelagic (oceanic) material derived from the remains of marine plants and animals that once inhabited the waters lying above. Red or brown radiolarian ooze is found along the zone of the Pacific North Equatorial Current, east of longitude 170° W, and on the floors of some deep Indonesian basins. A belt of diatom ooze occurs between latitudes 45° and 60° S and across the North Pacific, between Japan and Alaska. Calcareous globigerina ooze occurs in the shallower parts of the South Pacific, the dissolving power of the seawater at great depths being sufficient to dissolve calcareous material to such an extent that these oozes are not generally found at depths in excess of about 15,000 feet (4,600 metres). Silica-containing material, such as radiolarian and diatom ooze, is found at greater depths, but even these siliceous remains are dissolved at very great depths, where the characteristic deposit is red clay. Red clay, which covers no less than half of the Pacific floor, is believed to be formed of colloidal (extremely finely divided) clays derived essentially from the land.
On the abyssal plains, where sediments accumulate slowly, chemical and biological processes lead to the formation of metal-bearing coatings around objects such as the ear bones of fishes. The nodules so formed contain manganese, iron, nickel, copper, cobalt, and traces of other metals such as platinum. They cover large areas of the ocean floor in the Pacific. Similar processes form coatings, called manganese crusts, on the rock surfaces of seamounts.
The islands of the western region—including the Aleutians, the Kurils, the Ryukyus, Taiwan, the Malay Archipelago (including New Guinea), and New Zealand—are continental in character. Geologically, they consist partly of sedimentary rocks, and their structures are similar to those of the coastal mountain ranges of the adjacent continent.
A geologically important boundary between the continental, or “high,” islands and the numerous truly oceanic, or “low,” islands of the Pacific is the Andesite Line, a region of intense volcanic and seismic activity. In the northern and western Pacific the Andesite Line follows close to seaward the trend of the island arcs from the Aleutians southward to the Yap and Palau arcs, thence eastward through the Bismarck, Solomon, and Santa Cruz archipelagoes, and thence southward through the Samoa, Tonga, and Chatham groups and Macquarie Island to Antarctica. Islands to the west of the line are rich in andesite, a type of intrusive igneous rock; islands to the east (oceanic side) of it are essentially of basalt, an extrusive igneous rock.
The numerous oceanic islands of the Pacific are unevenly distributed. They lie, in the main, between the Tropics of Cancer and Capricorn and occur in great numbers in the western Pacific. The northernmost chain of oceanic islands is associated with the Hawaiian Ridge. The Hawaiian archipelago consists of about 2,000 islands, although the term Hawaiian Islands is usually applied to the small group that lies at the eastern end of the archipelago.
The numerous small islands of Micronesia lie mainly north of the Equator and to the west of the 180° meridian. Nearly all are coralline; the principal groups are the Marianas, the Marshalls, the Carolines, Kiribati (Gilbert Islands), and Tuvalu (Ellice Islands).
To the south of Micronesia lies Melanesia, which consists mostly of small coral islands. The region’s physiography is dominated by a group of large continental islands, however, including New Guinea. The principal Melanesian island groups are the Bismarck Archipelago, the Solomons, Vanuatu (New Hebrides), New Caledonia, and Fiji.
The immense area of Polynesia includes the Hawaiian Islands, the Phoenix Islands, Samoa, Tonga, the Cook Islands, the Society Islands, Tuamotu, and the Marquesas.
Evidence drawn from various geophysical fields—seismology, volcanology, gravimetry, and paleomagnetism (remanent magnetism)—points to the general validity of the theory of plate tectonics. All the major physical features in the Pacific are understood to originate in plate tectonics. The western Pacific arcs of volcanic islands and deep trenches are convergent zones where two plates are colliding, one being subducted (forced under the other). The East Pacific Rise is an active spreading centre where new crust is being created. The northeastern Pacific margin is the strike-slip zone where the American Plate and the Pacific Plate are gliding laterally past each other via the major San Andreas Fault system. In the southeastern Pacific, however, the Nazca Plate and the South American Plate are colliding to form the Andes Mountains along western South America and, a short distance offshore, the Peru-Chile Trench. The floor of the northeastern Pacific is remarkable for its several major fracture zones, which extend east and west and which, in some instances, are identifiable over distances of thousands of miles.
Of great geologic interest are the seamounts (submerged volcanoes), guyots (flat-topped seamounts), and oceanic islands of the Pacific. The numerous tropical islands of the Pacific are mainly coralline. The principal types of coral reefs—fringing, barrier, and atoll—as well as the guyots, which rise within the Pacific from the ocean floor in latitudes north and south of the tropics, are explained partially by the slow subsidence theory advanced by the English naturalist Charles Darwin during the 19th century and partially by the theory of plate tectonics.
Apr 9, 2024 · Introduction. Background. The Pacific Ocean is the largest of the world's five ocean basins (followed by the Atlantic Ocean, Indian Ocean, Southern Ocean, and Arctic Ocean). Strategically important access waterways include the La Perouse, Tsugaru, Tsushima, Taiwan, Singapore, and Torres Straits.
People also ask
Where is the Pacific Ocean located?
What does Pacific mean?
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Why is it called the Pacific Ocean?
The meaning of PACIFIC is tending to lessen conflict : conciliatory. How to use pacific in a sentence. tending to lessen conflict : conciliatory; rejecting the use of force as an instrument of policy; having a soothing appearance or effect…
- Birthing hurricanes. The Pacific Ocean stirs up some of the strongest hurricanes ever seen. For example, in 2018 the strongest storm of the year was Super Typhoon Mangkhut.
- The Ring of Fire. The Pacific basin is called the “Ring of Fire” because of the area of earthquake and volcanic activity around its edges. The resulting chain of volcanoes is roughly 25,000 miles long and springs to life where the Pacific tectonic plate slides against or collides into the other tectonic plates that circle it.
- The Mariana Trench. The Mariana Trench is one such deep ocean trench that sits along the Ring of Fire in the Mariana Archipelago east of the Philippines.
- Ocean acidification and ‘the blob’ Burning fossil fuels and releasing carbon dioxide into the air doesn't just alter the makeup of our atmosphere. Oceans, which absorb about 30 percent of the CO2 released into the atmosphere, are also highly susceptible to the changes taking place in a warming world.
Apr 11, 2024 · Pacific Islands, geographic region of the Pacific Ocean. It comprises three ethnogeographic groupings—Melanesia, Micronesia, and Polynesia—but conventionally excludes Australia, the Indonesian, Philippine, and Japanese archipelagoes, and the Ryukyu, Bonin, Volcano, and Kuril island arcs beyond Japan.
Pacific Ocean, Body of salt water extending from the Antarctic region in the south to the Arctic circle in the north and lying between the continents of Asia and Australia on the west and North and South America on the east.
