The exact time of the development of the Pacific oceans not known, but it may have developed around 250 million back after the breaking of Pangaea. It is the largest Ocean among the five oceans; area of the pacific ocean covers 1/3rd areas of the earth’s crust.

• The shape of the pacific ocean is triangular.
• It has the largest extensive Abyssal plains with average deep of 4500 meters.
• It has the largest number of Islands; around more than 2000 islands are found in the pacific ocean.
• The deepest trench is Mariana Trench which is around 11000 meters deep.
• The Pacific Ring of Fire which is the world’s largest area of volcanos and sources of earthquakes is a unique feature of the Pacific Ocean.

Continental Shelf

• The continental shelf surrounding the margin of the Pacific Ocean is controlled by the shape and structure of its coastline.
• On the eastern margin of this ocean the width of the shelf is rather narrow.
• Due to the presence of the Rockies and the Andes Mountains parallel to the west coasts of North and south Americas respectively the continental shelves have become very narrow.
• Their width is limited to only 80 km.
  However, on the western margin of this ocean, due to the absence of mountain chains or plateaus, the continental shelf is broad.
• The continental shelves adjoining the coasts of Australia, East Indies and East Asia are relatively much broader.
• Along these coasts the width of the shelves varies from 160 to 1600 km with their average depth hardly exceeding 1000 m.
• On these shelves are situated most of the islands and marginal seas.
  

Ridges

• Pacific Ocean has no central ridge.
• Only a few submarine ridges can be located here and there, mostly on the eastern margin of the ocean, and the submarine swells are found in the middle of the Pacific.
• One of the most important ridges known as the East Pacific ridge or Albatross Plateau (3000-4000 m. deep) is
  quite extensive.
• The north-east projection of the plateau is known as Cocos ridge and extends from the coast of Central America towards south-west.
• It is about 1600 km broad and bifurcates into two near 2◦ S lat.
• The eastern part is a narrow ridge named San Felix-Juan Fernandez ridge, less than 2000 m. deep and runs parallel to the Chilean coast.
• The western
  ridge moves to the south and forms a wide plateau between 20◦-40◦S lat., known as South Eastern Pacific plateau.
• The depth here is between 2000-4000m. Further south the same plateau narrows down in the form of a curved Pacific-Antarctic ridge where the depth is about 3500 m.

Ocean Basins

Many depressions and basins, separated by numerous swells, are also found in the Pacific Ocean.

1. Aleutian basin – north of the Aleutian island, this basin is 4000 m. deep.
2. Philippine basin – situated east of Philippine Islands, this basin extends up to 5◦ N. Its depth varies between 5000-6000 m. The western part of the basin is comparatively deeper than 6000m.
3. West Caroline basin. It is a 4000-5000 m. deep circular basin east of Philippine basin.
4. East Caroline basin – this basin is also 5000 m. deep.
5. Fiji basin – south of Fiji Island, Fiji basin is more than 4000 m.
6. East Australian basin – a 4000 m. deep basin, compact and circular in form, extends east of Australia with areas deeper than 5000 m. found in the north.
7. South Australian or Jeffrey’s basin – it is a 5000 m. longitudinal basin extending south of Australia.
8. South-western Pacific basin – it is a wide 6000 m. deep basin.
9. South-eastern Pacific basin – this 5000 m. deep and broad basin extends west of Peru and Chile with Baver deep of 5266 m. depth.
10. Pacific Antarctic basin. It extends south-west of Chile.

East Pacific Rise:

• The Pacific Ocean does not have central or mid- oceanic ridge like the Atlantic and the Indian Oceans, albeit there are a few scattered ridges having local importance.
• The East Pacific Rise or Ridge known as Albatross Plateau is 1600 km wide and it extends from north of New Zealand to the Californian coast.
• It sends off two branches between 23°S-35°S.
• The eastern branch merges with Chilean coast while the other branch moves southward in the name of Eastern Island Rise.

Deep Ocean

There are several trenches and deeps in the Pacific Ocean. These depressions are located either along the island arcs or mountain chains. It may be pointed out that the trenches are found mainly in the western Pacific Ocean.

FAQs related with Bottom Reliefs Of The Pacific Ocean

Ques 1. What are the bottom reliefs of the Pacific Ocean?

Answer: The bottom reliefs of the Pacific Ocean encompass a wide range of geological features on its seabed. These include oceanic trenches, volcanic island arcs, seamounts, abyssal plains, guyots, and oceanic plateaus, among others.

Ques 2. How are the bottom reliefs of the Pacific Ocean formed?

Answer: The formation of the bottom reliefs in the Pacific Ocean is influenced by various geological processes. Oceanic trenches, for example, are created by the convergence of tectonic plates, while volcanic island arcs result from subduction zones. Seamounts are formed by volcanic activity, and abyssal plains are shaped by sedimentation over time.

Ques 3. What is the significance of the bottom reliefs in the Pacific Ocean?

Answer: The bottom reliefs of the Pacific Ocean play crucial roles in the Earth’s geology, oceanography, and marine ecology. Oceanic trenches are associated with subduction zones and major earthquakes, making them important in understanding seismic activity. Volcanic island arcs contribute to the formation of new land masses. Seamounts and underwater plateaus provide essential habitats for various marine species and support unique ecosystems. Additionally, the exploration of these features helps us gain insights into the planet’s tectonic processes and the potential for resource exploration and conservation efforts in the deep-sea environments.

Read Also : Bottom Reliefs Of The Atlantic Ocean