Pacific Ocean- the largest on the planet. It covers more than half of the entire water surface of the Earth and has an area of ​​178 ml. sq. km. and stretched from Japan to America. The average depth of the ocean is 4 km.

Discovery of the Pacific Ocean

It is believed that the first person to visit the Pacific Ocean on a ship was Magellan . In 1520, he circumnavigated South America and saw new expanses of water. Since during the entire journey Magellan’s team did not encounter a single storm, then new ocean called " Quiet«.

Victoria is the only returning ship of Magellan's expedition.

But even earlier, in 1513, the Spaniard Vasco Nunez de Balboa headed south from Colombia to a place where, as he was told, there was a rich country with a large sea. Having reached the ocean, the conquistador saw an endless expanse of water stretching to the west, and called it “ South Sea«.

Bottom relief

The bottom topography is extremely varied. Located in the eastEast Pacific Rise, where the terrain is relatively flat. In the center there are basins and deep-sea trenches. The average depth is 4,000 m, and in some places exceeding 7 km. The bottom of the center of the ocean is covered with products of volcanic activity with high contents of copper, nickel and cobalt. The thickness of such deposits in some areas can be 3 km. The age of these rocks begins with the Jurassic and Cretaceous periods.

At the bottom there are several long chains of seamounts formed as a result of the action of volcanoes: d ora of the Emperor, Louisville and the Hawaiian islands. There are about 25,000 islands in the Pacific Ocean. This is more than in all other oceans combined. Most of them are located south of the equator.

Islands are classified into 4 types:

1. Continental Islands. Very closely related to the continents. Includes New Guinea, the islands of New Zealand and the Philippines;
2. High Islands. Appeared as a result of underwater volcanic eruptions. Many of the modern high islands have active volcanoes. For example Bougainville, Hawaii and Solomon Islands;
3. Coral reefs;
4. Coral raised platforms;

The last two types of islands are huge colonies of coral polyps that form coral reefs and islands.

Climate

The large extent of the ocean from north to south quite logically explains the diversity of climatic zones - from equatorial to Antarctic. The most extensive zone is the equatorial one. Throughout the year, the temperature here does not drop below 20 degrees. Temperature fluctuations throughout the year are so small that we can safely say that it is always +25 there. There is a lot of precipitation, more than 3,000 mm. per year. Very frequent cyclones are typical.

Seasonal phenomenon in the Pacific Ocean - cyclones

The amount of precipitation is greater than the amount of water evaporating. Rivers, which bring more than 30 thousand m³ of fresh water into the ocean annually, make surface water less saline than in other oceans.

Inhabitants of the Pacific Ocean

The ocean is famous for its rich flora and fauna. It is home to about 100 thousand species of animals. Such diversity is not found in any other ocean. For example, the second largest ocean, the Atlantic, is inhabited by “only” 30 thousand species of animals.

There are several places in the Pacific Ocean where the depth exceeds 10 km. These are the famous Mariana Trench, the Philippine Trench and the Kermadec and Tonga trenches. Scientists were able to describe 20 species of animals living at such great depths.

Half of all seafood consumed by humans is caught in the Pacific Ocean. Among the 3 thousand species of fish, industrial-scale fishing is open for herring, anchovies, mackerel, sardines, etc.

• This ocean is so huge that its maximum width is equal to half the earth's equator, i.e. more than 17 thousand km.
• The fauna is large and diverse. Even now, new ones are regularly discovered there, unknown to science animals. So, in 2005, a group of scientists discovered about 1000 species of decapod cancer, two and a half thousand mollusks and more than a hundred crustaceans.
• The deepest point on the planet is in the Pacific Ocean in the Mariana Trench. Its depth exceeds 11 km.
• The most high mountain in the world is located in the Hawaiian Islands. It's called Muana Kea and is an extinct volcano. The height from base to top is about 10,000 m.
• Located on the ocean floor Pacific Volcanic Ring of Fire, which is a chain of volcanoes located along the perimeter of the entire ocean.

The Pacific Ocean was named after Ferdinand Magellan, who crossed the Pacific Ocean from the west coast in 1521 South America to the coast of South Asia, and never encountered a storm, which is why he called the ocean “Pacific”.

Later, the second after Magellan, the Pacific Ocean was crossed by the English navigator Francis Drake (1540-1596), whose journey was accompanied by very unfavorable weather, and who declared that a more appropriate name for this ocean was “Mad Ocean.” Nowadays, the Pacific Ocean is often called the Great Ocean.

The Pacific Ocean is called the Great Ocean for its size (see Fig. 1). This is the largest body of water on Earth. This is the deepest and warmest ocean in the surface layer. The highest wind waves and the most destructive tropical hurricanes form here. It ranks first in the number of islands and is distinguished by a variety of natural conditions.

The ocean is located on both sides of the equator and the 180th meridian. It occupies almost half the area of ​​the entire World Ocean and washes the shores of five continents of the Earth.

Rice. 1. Pacific Ocean

Geographical position of the ocean

The Pacific Ocean covers more than 30% of the Earth's surface and is larger in area than all continents. From north to south it stretches for 16,000 km, and from west to east – more than 19,000 km (see Fig. 2).

· From the north, the Pacific Ocean is limited by the entrance to the Bering Strait.

· In the west, its border runs along the shores of Asia to the Strait of Malacca, along the islands of Sumatra, Java, Timor, New Guinea, through the Torres Strait, along the east coast of Australia and the island of Tasmania, then along 1470 E. to Antarctica.

· The southern border of the Pacific Ocean is the shores of Antarctica.

· The eastern border of the Pacific Ocean is the shores of North and South America, the Drake Passage, and the Antarctic Peninsula of Antarctica.

Rice. 2. Physical card Pacific Ocean

Geology of the Pacific

The Pacific Ocean occupies a single ancient Pacific lithospheric plate, which interacts with other plates at its boundaries.

The edges of this lithospheric plate are subducted under the lithospheric plates surrounding the Pacific Ocean, and therefore many deep-sea trenches and narrow, deep basins have formed around the Pacific Ocean. These are the deepest places in the ocean and on the whole Earth. Deep-sea trenches and island arcs are areas of active earth's crust. Earthquakes and sometimes tsunamis occur here regularly.

Volcanoes are much more widespread at the bottom of the Pacific Ocean. When underwater volcanoes erupt, islands are sometimes formed, many of which are short-lived and washed away by water.

If you look closely at the map, you will notice that along each deep-sea trench there is a chain of islands. These islands created active and dormant underwater volcanoes along the boundaries of lithospheric plates. They ring the Pacific Ocean and form the famous Pacific “Ring of Fire” (see Fig. 3).

Rice. 3. Pacific "Ring of Fire"

Relief of the ocean floor

The underwater relief of the vast ocean is diverse (see Fig. 4). At the bottom of the Pacific Ocean there are vast basins, individual mountains, hills, and in the southern part two rises that form the mid-ocean ridge.

Mid-ocean ridges stretch for 11,700 km. Unlike other oceans, they do not occupy a middle position, but are strongly shifted to the southeast, where the boundaries of lithospheric plates pass.

The Pacific Ocean floor is characterized by isolated rises and entire chains of seamounts. The tops of many underwater ridges and rises form islands, of which there are more than 10 thousand in the ocean, with a total area of ​​36 million sq. km. The largest of the islands are Hawaiian.

Rice. 4. Relief of the Pacific Ocean floor

At the bottom there are many volcanic mountains called guyots (named after the discoverer, American geographer and geologist Arnold Guyot) (see Fig. 5).

Rice. 5. Guyot

They have flat tops topped with coral structures. Due to the subsidence of the earth's crust, the guyots are submerged by 2 - 2.5 km, and around some of them small coral islands - atolls - are formed.

Numerous islands of the central part of the ocean are united under the general name Oceania.

Climate

The ocean climate is varied and varies from equatorial to subarctic in the north and Antarctic in the south.

The widest part is located in hot zones. Therefore, the average temperature in the surface layer is 2 degrees. higher than in the Atlantic and Indian oceans.

The average salinity of the ocean is 34.5 ppm - this is lower than in other oceans, since more fresh water enters it with precipitation and rivers than evaporates (see Fig. 6).

Rice. 6. Climate map of the Pacific Ocean

The stretch of the ocean from the northern to the southern polar latitudes determines the climatic diversity in its spaces:

The western part of the ocean is characterized by monsoons

Moderate latitudes are characterized by winds that are relatively unstable in direction and quite frequent recurrence of storm winds with a speed of more than 16 m/sec, and their maximum speed at times reaches 45 m/sec

In tropical latitudes - trade winds

In the tropics, typhoons often form (from the Chinese “tai feng” - big wind) - a tropical cyclone, within which hurricane-force winds blow at speeds of up to 100 km/h.

Pacific Currents

Constant winds - trade winds and westerly winds of temperate latitudes, sweeping over the expanses of water in the Pacific Ocean, create powerful currents. Currents in the Pacific Ocean form two complete circles: in the northern and southern hemispheres.

Let's trace the formation of the main currents of the Pacific Ocean on the map (see Fig. 7).

Rice. 7. Diagram of Pacific Ocean currents

Trade winds pick up the upper layer of water and drive it along the equator to the west, forming trade wind currents. So much water flows to the west that the ocean level would be skewed, so between these currents an inter-trade wind is formed, and the water flows back to the eastern part of the ocean. When trade wind currents approach the coasts of continents, water is pushed away from the coast and moves away from the equator along the coasts, forming the Kuroshio and East Australian currents. Once in temperate latitudes, the water streams are picked up by westerly winds, which pull them east. In the northern hemisphere, the North Pacific Current is formed, and in the southern hemisphere, water flows into the Western Wind Current. At the eastern edges of the ocean, part of the water along the coasts of the continents returns back to the equator, forming the cold Peruvian and California currents. Near the equator, the water is picked up again by the trade wind.

This is how complete circles of the main ocean currents are formed.

Organic world

The organic world of the Pacific Ocean is rich and diverse. It is the richest in the number of species of living organisms. In general, about 100 thousand species of animals live in the ocean. Plant plankton alone has about 1,300 species. It accounts for half of the total mass of living organisms in the World Ocean.

Brown algae is abundant in the cold and temperate waters of the Pacific Ocean. IN Southern Hemisphere in these latitudes grows a giant from the world of algae 200 m long.

Coral reefs are one of the wonders of the tropical seas. Coral structures of various colors and shapes create a magical world underwater. Among the purple, green, orange, yellow branches of coral buildings, light silhouettes of fish flash; shellfish, starfish and algae live here.

Coral reefs are created by living organisms - coral polyps living in colonies (see Fig. 8). A branched coral colony has been growing for many years, the growth rate is 10-20 cm per year. 


Rice. 8. Coral

For the development of corals, sea water with a salinity of 27-40‰ and a temperature of at least +20 ºС is required. 


Corals live only in the upper 50-meter layer of clean, transparent water.


The Pacific Ocean is called the Great Ocean for its size. This is the largest body of water on Earth.

In size it is comparable to the Ural Range.

Ocean in people's lives

About half of the world's population lives along the shores of the Pacific Ocean. The lives of many of them are inextricably linked with the ocean and depend on it.

The longest sea ​​routes run across this ocean, connecting port cities of different continents. However economic activity people has led to a serious problem of pollution of the Great Ocean. Entire islands of garbage have accumulated in its waters.

References

MainI

1. Geography. Land and people. 7th grade: Textbook for general education. uch. / A.P. Kuznetsov, L.E. Savelyeva, V.P. Dronov, series “Spheres”. – M.: Education, 2011.

2. Geography. Land and people. 7th grade: atlas, “Spheres” series.

Additional

1. N.A. Maksimov. Behind the pages of a geography textbook. – M.: Enlightenment.

1. Encyclopedia Around the World ().

2. Russian Geographical Society ().

4. Tutorial in geography ().

5. Gazetteer ().

6. Fascinating journey on water ().

PACIFIC OCEAN

REGIONAL OVERVIEW

The Pacific and Indian oceans have in their nature a lot common features. The biogeographical Indo-Pacific tropical region covers the corresponding

warring areas of both oceans. The border between the oceans in their southern parts is purely arbitrary.

The Pacific Ocean is the largest of the oceans. He ranks 49.5 % in area and 53.0% by volume of water in the World Ocean, more than 1/3 of the entire earth's surface. The ocean extends more than 19 thousand km from east to west and 16 thousand km from north to south. It divides (and together It connects five continents, which determines its enormous overall physical-geographical and economic-geographical significance.

Underwater continental margins. For

underwater continental margins occupying less than 10 % area of ​​the Pacific Ocean bottom (Fig. 90), almost all relief features and geological structure, typical of the underwater margins of continents in general. In the relief of the shelf, if it occupies relatively large areas, transgressive plains with sub-aerial relict relief (for example, underwater river valleys on the Java shelf and on the Bering Sea shelf). Common on the Korean shelf and East China Sea ridge landforms^ formed by tidal currents. In equatorial-tropical waters, various coral buildings. The Antarctic shelf has unique features. Most of it lies at depths of more than 200 m, the surface of the shelf is very dissected, along with underwater tectonic rises there are deep depressions - grabens. Continental slope in Ti-

home ocean is heavily dissected underwater canyons. The largest group of submarine canyons on the continental slope of North America has been studied most thoroughly. The continental slope is very clearly defined off the coast of Australia and New Zealand, where it is also dissected by submarine canyons. Large submarine canyons are known on the continental slope in the Bering Sea. The structure of the continental slope to the west of the state of California (USA) is peculiar. The bottom topography is large-block, typical “borderland”. This is a special type of morphostructure, characterized by a combination of horst underwater hills and depression-grabens between them. The continental slope of Antarctica is distinguished by its large width, varied relief, and dissected by submarine canyons.

The continental foothills are most fully expressed on the North American submarine margin. It is distinguished by very large cones of turbidity flows, merging into a single inclined plain, bordering the continental slope with a wide strip.

The underwater margin of New Zealand represents a unique continental structure. Its area is 10 times larger than the area of ​​the New Zealand islands. This is the underwater New Zealand plateau, consisting of two flat-topped rises (Campbell And Chatham) and the depressions between them (Bounty). On all sides it is limited by the continental slope, bordered on the outer side by the continental foot. This underwater macrostructure should also include the Late Mesozoic underwater Lord Howe Ridge.

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According to the relief features, the Pacific Ocean bed is divided into: 1) northern and central parts; 2) southern and 3) southeastern parts. General plan The location of the main orographic elements of the northern and central parts of the Pacific Ocean floor is formed from a system of giant arcs, convex in plan to the northeast. These are the arcs:

1) Hawaiian ridge;

2) the Marcus-Necker – Line – Tuamotu ridge systems;

3) Marshall Islands and Gilbert Islands - Tuvalu;

4) the Caroline Islands and the Ka-pingamarangi shaft;

5) Vala Euriapic.

This plan undoubtedly reflects an important feature of the structure of the floor of the Pacific Ocean, which is still unknown to us. The previously noted bends of linear magnetic anomalies, as well as the outlines of parts of the oceanic crust of different ages, although the determination of their age is arbitrary and controversial, generally correspond to this general pattern of the orographic framework of the northern and central parts of the Pacific Ocean.

Several mountain systems (the underwater foundations of the Society Islands, Tubuai, and the Southern Cook Islands) are not included in the systems mentioned above and are located parallel to them. Some underwater ridges and hills have a completely different extent (Imperial Mountains, Shatsky, Hess and Magellan hills, Marquesas Islands and Phoenix Islands). The Manihiki Plateau with the Northern Cook Islands located on its elevated periphery stands out sharply.

The most important orographic and tectonic elements of the Pacific Ocean floor are fault zones of enormous length and predominantly latitudinal and sublatitudinal strike. Most of them are confined to the largest Northeast basin of the Pacific Ocean: approximately parallel to each other (from north to south) are the Chinook, Surveyor, Mendo-sino, Pioneer, Murray, Molokai, Clarion, Clipperton, Galapagos, Marquesas fault zones, islands. They are clearly expressed in relief in the form of complexes of specific positive and negative relief forms. The isobath pattern is specific. They seem to form a staircase descending in a series of giant steps from the Marquesas fault to the Murray fault. Mountain uplifts divide the northern and central parts of the Pacific Ocean into a series of basins. The largest, the Northeastern one, is bounded in the west and southwest by the Imperial Mountains, the Hawaiian and Line Tuamotu ridges, and in the southeast by the East Pacific Rise. To the west of the Imperial Mountains lies the Northwestern Basin, in the middle part of which the Shatsky Upland is located. From the south, the basin is limited by the Markus-Necker Mountains. Both basins are characterized by predominantly hilly terrain. In the northern part of the North-Eastern Basin, significant areas are occupied by the Aleutian, Alaskan and Taft flat abyssal plains, there are many guyots, and several fault zones are distinguished that do not coincide along the strike with latitudinal faults (the Imperial Fracture Zone and the meridional faults Amlia and Adak). Both basins are included in the number of the deepest basins in the World Ocean: the maximum depth of the North-Eastern basin is 6741 m, the North-Western basin is 6671 m.

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At the bottom of the Pacific Ocean, three morphostructural regions can be distinguished: 1) western geosynclinal, 2) central platform, 3) eastern region. The first of them is characterized by the collapse of Meso-Cenozoic folded land formations, in the place of which modern geosynclinal seas appeared. The most elevated parts of the collapse area with preserved folded structures represent islands and island arcs, while the most deeply sunken parts of the former landmass correspond to sea depressions (Figure 8).

From south to north, the subsidence becomes increasingly younger. If the Australanesian avalanche belt between New Zealand and New Guinea is characterized by fragmentation and subsidence in the Paleogene and early Neogene, then in the Indonesian archipelago subsidence developed in the Pliocene-Quaternary time, further to the north (part of the Bering Sea and other seas Far East) subsidences become even younger - from Quaternary to Holocene. An important feature of the morphological structure of the region under consideration is expressed by young troughs in the form of modern abyssal trenches.

The modern bottom of the central part of the ocean was formed on the submerged foundation of the Pacific Platform, which in some parts is of unequal age. A characteristic morphostructural feature here is diagonal system oceanic faults NW--SE, WNW--ESE directions.

Figure 8 Brief overview main elements of the Pacific Ocean

In the northern part of the region under consideration, along with a system of diagonal lines of morphostructure associated, as indicated, with faults, lines of latitudinal and meridional directions are also distinguished. They are clearly expressed by uplifts of the ocean floor with a northwestern strike, and in the northern part by the Hawaiian Ridge. The combination of a system of orthogonal and diagonal fault lines further convinces that the central part of the Pacific Ocean belongs to a platform morphostructure.

In the eastern morphostructural region of the ocean, the northern and southern parts are distinguished. The first of them is distinguished by a system of faults that extend almost parallel to the shores North America to the Hawaiian and median ranges. It is characterized by: complex topography, sharply dissected along fault lines and the spread of young Quaternary volcanoes (guyots - Figure 10).

The nature of the morphostructure of the bottom of the southern half of the considered part of the ocean is significantly different. No planetary oceanic rifts are known south of the equator, general character the morphostructure becomes very similar to the Atlantic. Indeed, the South Pacific underwater ridge stretches across the southeastern part of the ocean, giving way to the East Pacific ridge in the north. The northernmost link of this oceanic mountain chain is the underwater Cocos Ridge.

Oceanic basins are located symmetrically in relation to the named underwater ridges of the southeastern part of the ocean and, moreover, are separated by spurs of the median ridge, which greatly increases the similarity with the bottom Atlantic Ocean. Like the North Atlantic, here the median ridge ends in the north with the vast oceanic underwater plateau Albatross.

With a sharp increase in the thickness of the crust in the southeastern part of the ocean, the morphological similarity of this part of the Pacific Ocean with the Atlantic is enhanced by the difference in the deep structure of the crust in this part of the ocean from its other parts. Thus, we can now quite reasonably speak about the Atlantic type of morphostructure of the southeastern part of the Pacific Ocean. This morphostructure is probably associated with the fragmentation and subsidence of younger platform structures. It is possible that the platform structures of the southeastern Pacific Ocean are younger than those in the Atlantic.

The underwater continental margins occupy 10% of the Pacific Ocean. The shelf topography displays the features of transgressive plains with subaerial relict topography. Such forms are characteristic of underwater river valleys on the Java shelf and the Bering Sea shelf. On the Korean shelf and the shelf of the East China Sea, ridge landforms formed tidal currents. Various coral structures are common on the shelf of equatorial-tropical waters. Most of the Antarctic shelf lies at depths of more than 200 m, the surface is very dissected, underwater tectonic elevations alternate with deep depressions - grabens. The continental slope of North America is heavily dissected by submarine canyons. Large submarine canyons are known on the continental slope of the Bering Sea. The continental slope of Antarctica is distinguished by its wide width, diversity and dissected relief. Along North America, the continental foot is distinguished by very large cones of turbidity flows, merging into a single inclined plain, bordering the continental slope with a wide strip.

The underwater margin of New Zealand has a peculiar continental structure. Its area is 10 times larger than the area of ​​the islands themselves. This underwater New Zealand plateau consists of the flat-topped Campbell and Chatham rises and the Bunkie depression between them. On all sides it is limited by the continental slope, bordered by the continental foot. This also includes the Late Mesozoic underwater Lord Howe Ridge.

Several mountain systems (the underwater foundations of the Society Islands, Tubuai, and the Southern Cook Islands) are not included in the systems mentioned above and are located parallel to them. Some underwater ridges and hills have a completely different strike. The Manihiki Plateau with the Northern Cook Islands located on its elevated periphery stands out sharply.

The most important orographic and tectonic elements of the Pacific Ocean floor are fault zones of enormous length and predominantly latitudinal and sublatitudinal strike. Most of them are confined to the largest Northeast basin of the Pacific Ocean: approximately parallel to each other (from north to south) are the Chinook, Surveyor, Mendo-Sino, Pioneer fault zones, the Marquesas fault zone, and the Marquesas Islands. They are clearly expressed in the relief in the form of complexes of specific positive and negative relief forms (Figure 8). Mountain uplifts divide the northern and central parts of the Pacific Ocean into a series of basins. The largest, the Northeastern one, is bounded in the west and southwest by the Imperial Mountains, the Hawaiian and Line Tuamotu ridges, and in the southeast by the East Pacific Rise. To the west of the Imperial Mountains lies the Northwestern Basin, in the middle part of which the Shatsky Upland is located. From the south, the basin is limited by the Markus-Necker Mountains. Both basins are characterized by predominantly hilly terrain. In the northern part of the North-Eastern Basin, significant areas are occupied by the Aleutian, Alaskan and Taft flat abyssal plains, there are many guyots, and several fault zones are distinguished that do not coincide along the strike with the latitudinal faults (the Imperial fault zone and the meridional faults Amlia and Adak). Both basins are among the deepest basins in the World Ocean: the maximum depth of the North-Eastern basin is 6741 m, the North-Western basin is 6671 m.

Figure 9 Map of the Pacific Ocean floor

In the southwestern sector of the described part of the Pacific Ocean there are: the East Mariana Basin, bounded by the Marcus Necker Mountains, the Marshall and Caroline Islands with a maximum depth of 6770 m; to the south follow the West Carolina basins (5650 m); East Caroline, within which the deep Mussau trough (7021 m) is located; Melanesian (5634 m), in the middle part of which rises the previously described mountain (raised atoll) Nauru; The central basin, in which numerous oceanic rises are located - the Magellan Rise, the underwater foundations of the Phoenix and Takelau islands, the Manihiki Plateau; in the middle part, the basin is crossed by the Nova Canton fault zone; the maximum depth of the basin is confined to one of the troughs of the zone (7600 m).

The southern floor of the Pacific Ocean is divided into two parts by the South Pacific Mid-Ocean Ridge. To the north of it is the South Pacific Basin. The maximum depths of the basin are in its northern part, near the Tonga Trench (6090 m). In the middle part, the basin is divided by a ridge of seamounts associated with the Eltanin fault zone.

To the south of the South Pacific Rise lies the vast Bellingshausen Basin (5020 m), in which, due to the intensive accumulation of iceberg material, a vast area is occupied by flat abyssal plains. Between the New Zealand landmass, the Lord Howe Rise and Australia is the Tasman Basin with numerous guyots. Guyot is a seamount in the ocean, which is an extinct volcano with a flat top, formed under the influence of long-term wave abrasion. (Figure 10).

Figure 10 Basic landforms of the ocean floor

A special region of the Pacific Ocean floor - the southeast - is located east of the East Pacific Ridge. It is separated from the Bellingshausen Basin by the Chilean Uplift. Apparently, this is a branch of the middle ridge. The blocky ridges of Sala y Gomez and Nazca divide this part of the ocean floor into two basins: the Chilean (depth 5000 m) and the Peruvian (4525 m). In the western part of the Peruvian Basin there is a poorly studied Galapagos uplift, which separates the small Bauer Basin (5126 m) from the Peruvian Basin. To the north of the Galapagos fault is the Guatemala Basin with a maximum depth of 4199 m. All basins are characterized by the relief of abyssal hills and extremely slow sedimentation. This is due to the fact that they are separated from the adjacent continents by deep-sea trenches, which serve as traps for terrigenous material entering the ocean from the continents.

The geodynamics of the Pacific Ocean floor is determined by the lateral movements of several large lithospheric plates - Pacific, North American, Antarctic, Peruvian-Chilean - and smaller ones - Panama, Guatemala, Tehuantepec (Figure 11).

Figure 11 Earth's lithospheric plates